wallet.cpp

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "wallet/wallet.h"

#include "checkpoints.h"
#include "coincontrol.h"
#include "consensus/upgrades.h"
#include "consensus/validation.h"
#include "consensus/consensus.h"
#include "init.h"
#include "key_io.h"
#include "main.h"
#include "net.h"
#include "script/script.h"
#include "script/sign.h"
#include "timedata.h"
#include "utilmoneystr.h"
#include "zcash/Note.hpp"
#include "crypter.h"

#include <assert.h>

#include <boost/algorithm/string/replace.hpp>
#include <boost/filesystem.hpp>
#include <boost/thread.hpp>

using namespace std;
using namespace libzcash;

/**
 * Settings
 */
CFeeRate payTxFee(DEFAULT_TRANSACTION_FEE);
CAmount maxTxFee = DEFAULT_TRANSACTION_MAXFEE;
unsigned int nTxConfirmTarget = DEFAULT_TX_CONFIRM_TARGET;
bool bSpendZeroConfChange = true;
bool fSendFreeTransactions = false;
bool fPayAtLeastCustomFee = true;

/**
 * Fees smaller than this (in satoshi) are considered zero fee (for transaction creation)
 * Override with -mintxfee
 */
CFeeRate CWallet::minTxFee = CFeeRate(1000);

/** @defgroup mapWallet
 *
 * @{
 */

struct CompareValueOnly
{
    bool operator()(const pair<CAmount, pair<const CWalletTx*, unsigned int> >& t1,
                    const pair<CAmount, pair<const CWalletTx*, unsigned int> >& t2) const
    {
        return t1.first < t2.first;
    }
};

std::string JSOutPoint::ToString() const
{
    return strprintf("JSOutPoint(%s, %d, %d)", hash.ToString().substr(0,10), js, n);
}

std::string COutput::ToString() const
{
    return strprintf("COutput(%s, %d, %d) [%s]", tx->GetHash().ToString(), i, nDepth, FormatMoney(tx->vout[i].nValue));
}

const CWalletTx* CWallet::GetWalletTx(const uint256& hash) const
{
    LOCK(cs_wallet);
    std::map<uint256, CWalletTx>::const_iterator it = mapWallet.find(hash);
    if (it == mapWallet.end())
        return NULL;
    return &(it->second);
}

// Generate a new spending key and return its public payment address
libzcash::PaymentAddress CWallet::GenerateNewZKey()
{
    AssertLockHeld(cs_wallet); // mapZKeyMetadata
    // TODO: Add Sapling support
    auto k = SproutSpendingKey::random();
    auto addr = k.address();

    // Check for collision, even though it is unlikely to ever occur
    if (CCryptoKeyStore::HaveSproutSpendingKey(addr))
        throw std::runtime_error("CWallet::GenerateNewZKey(): Collision detected");

    // Create new metadata
    int64_t nCreationTime = GetTime();
    mapZKeyMetadata[addr] = CKeyMetadata(nCreationTime);

    if (!AddZKey(k))
        throw std::runtime_error("CWallet::GenerateNewZKey(): AddZKey failed");
    return addr;
}

// Generate a new Sapling spending key and return its public payment address
SaplingPaymentAddress CWallet::GenerateNewSaplingZKey()
{
    AssertLockHeld(cs_wallet); // mapSaplingZKeyMetadata
    
    auto sk = SaplingSpendingKey::random();
    auto fvk = sk.full_viewing_key();
    auto addr = sk.default_address();
    
    // Check for collision, even though it is unlikely to ever occur
    if (CCryptoKeyStore::HaveSaplingSpendingKey(fvk)) {
        throw std::runtime_error("CWallet::GenerateNewSaplingZKey(): Collision detected");
    }
    
    // Create new metadata
    int64_t nCreationTime = GetTime();
    mapSaplingZKeyMetadata[addr] = CKeyMetadata(nCreationTime);
    
    if (!AddSaplingZKey(sk, addr)) {
        throw std::runtime_error("CWallet::GenerateNewSaplingZKey(): AddSaplingZKey failed");
    }
    // return default sapling payment address.
    return addr;
}

// Add spending key to keystore 
bool CWallet::AddSaplingZKey(
    const libzcash::SaplingSpendingKey &sk,
    const boost::optional<libzcash::SaplingPaymentAddress> &defaultAddr)
{
    AssertLockHeld(cs_wallet); // mapSaplingZKeyMetadata

    if (!CCryptoKeyStore::AddSaplingSpendingKey(sk, defaultAddr)) {
        return false;
    }
    
    if (!fFileBacked) {
        return true;
    }

    // TODO: Persist to disk
    
    return true;
}


// Add spending key to keystore and persist to disk
bool CWallet::AddZKey(const libzcash::SproutSpendingKey &key)
{
    AssertLockHeld(cs_wallet); // mapZKeyMetadata
    auto addr = key.address();

    if (!CCryptoKeyStore::AddSproutSpendingKey(key))
        return false;

    // check if we need to remove from viewing keys
    if (HaveSproutViewingKey(addr))
        RemoveSproutViewingKey(key.viewing_key());

    if (!fFileBacked)
        return true;

    if (!IsCrypted()) {
        return CWalletDB(strWalletFile).WriteZKey(addr,
                                                  key,
                                                  mapZKeyMetadata[addr]);
    }
    return true;
}

CPubKey CWallet::GenerateNewKey()
{
    AssertLockHeld(cs_wallet); // mapKeyMetadata
    bool fCompressed = CanSupportFeature(FEATURE_COMPRPUBKEY); // default to compressed public keys if we want 0.6.0 wallets

    CKey secret;
    secret.MakeNewKey(fCompressed);

    // Compressed public keys were introduced in version 0.6.0
    if (fCompressed)
        SetMinVersion(FEATURE_COMPRPUBKEY);

    CPubKey pubkey = secret.GetPubKey();
    assert(secret.VerifyPubKey(pubkey));

    // Create new metadata
    int64_t nCreationTime = GetTime();
    mapKeyMetadata[pubkey.GetID()] = CKeyMetadata(nCreationTime);
    if (!nTimeFirstKey || nCreationTime < nTimeFirstKey)
        nTimeFirstKey = nCreationTime;

    if (!AddKeyPubKey(secret, pubkey))
        throw std::runtime_error("CWallet::GenerateNewKey(): AddKey failed");
    return pubkey;
}

bool CWallet::AddKeyPubKey(const CKey& secret, const CPubKey &pubkey)
{
    AssertLockHeld(cs_wallet); // mapKeyMetadata
    if (!CCryptoKeyStore::AddKeyPubKey(secret, pubkey))
        return false;

    // check if we need to remove from watch-only
    CScript script;
    script = GetScriptForDestination(pubkey.GetID());
    if (HaveWatchOnly(script))
        RemoveWatchOnly(script);

    if (!fFileBacked)
        return true;
    if (!IsCrypted()) {
        return CWalletDB(strWalletFile).WriteKey(pubkey,
                                                 secret.GetPrivKey(),
                                                 mapKeyMetadata[pubkey.GetID()]);
    }
    return true;
}

bool CWallet::AddCryptedKey(const CPubKey &vchPubKey,
                            const vector<unsigned char> &vchCryptedSecret)
{

    if (!CCryptoKeyStore::AddCryptedKey(vchPubKey, vchCryptedSecret))
        return false;
    if (!fFileBacked)
        return true;
    {
        LOCK(cs_wallet);
        if (pwalletdbEncryption)
            return pwalletdbEncryption->WriteCryptedKey(vchPubKey,
                                                        vchCryptedSecret,
                                                        mapKeyMetadata[vchPubKey.GetID()]);
        else
            return CWalletDB(strWalletFile).WriteCryptedKey(vchPubKey,
                                                            vchCryptedSecret,
                                                            mapKeyMetadata[vchPubKey.GetID()]);
    }
    return false;
}


bool CWallet::AddCryptedSproutSpendingKey(
    const libzcash::SproutPaymentAddress &address,
    const libzcash::ReceivingKey &rk,
    const std::vector<unsigned char> &vchCryptedSecret)
{
    if (!CCryptoKeyStore::AddCryptedSproutSpendingKey(address, rk, vchCryptedSecret))
        return false;
    if (!fFileBacked)
        return true;
    {
        LOCK(cs_wallet);
        if (pwalletdbEncryption) {
            return pwalletdbEncryption->WriteCryptedZKey(address,
                                                         rk,
                                                         vchCryptedSecret,
                                                         mapZKeyMetadata[address]);
        } else {
            return CWalletDB(strWalletFile).WriteCryptedZKey(address,
                                                             rk,
                                                             vchCryptedSecret,
                                                             mapZKeyMetadata[address]);
        }
    }
    return false;
}

bool CWallet::AddCryptedSaplingSpendingKey(const libzcash::SaplingFullViewingKey &fvk,
                                           const std::vector<unsigned char> &vchCryptedSecret,
                                           const boost::optional<libzcash::SaplingPaymentAddress> &defaultAddr)
{
    if (!CCryptoKeyStore::AddCryptedSaplingSpendingKey(fvk, vchCryptedSecret, defaultAddr))
        return false;
    if (!fFileBacked)
        return true;
    {
        // TODO: Sapling - Write to disk
    }
    return false;
}

bool CWallet::LoadKeyMetadata(const CPubKey &pubkey, const CKeyMetadata &meta)
{
    AssertLockHeld(cs_wallet); // mapKeyMetadata
    if (meta.nCreateTime && (!nTimeFirstKey || meta.nCreateTime < nTimeFirstKey))
        nTimeFirstKey = meta.nCreateTime;

    mapKeyMetadata[pubkey.GetID()] = meta;
    return true;
}

bool CWallet::LoadZKeyMetadata(const SproutPaymentAddress &addr, const CKeyMetadata &meta)
{
    AssertLockHeld(cs_wallet); // mapZKeyMetadata
    mapZKeyMetadata[addr] = meta;
    return true;
}

bool CWallet::LoadCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret)
{
    return CCryptoKeyStore::AddCryptedKey(vchPubKey, vchCryptedSecret);
}

bool CWallet::LoadCryptedZKey(const libzcash::SproutPaymentAddress &addr, const libzcash::ReceivingKey &rk, const std::vector<unsigned char> &vchCryptedSecret)
{
    return CCryptoKeyStore::AddCryptedSproutSpendingKey(addr, rk, vchCryptedSecret);
}

bool CWallet::LoadZKey(const libzcash::SproutSpendingKey &key)
{
    return CCryptoKeyStore::AddSproutSpendingKey(key);
}

bool CWallet::AddSproutViewingKey(const libzcash::SproutViewingKey &vk)
{
    if (!CCryptoKeyStore::AddSproutViewingKey(vk)) {
        return false;
    }
    nTimeFirstKey = 1; // No birthday information for viewing keys.
    if (!fFileBacked) {
        return true;
    }
    return CWalletDB(strWalletFile).WriteSproutViewingKey(vk);
}

bool CWallet::RemoveSproutViewingKey(const libzcash::SproutViewingKey &vk)
{
    AssertLockHeld(cs_wallet);
    if (!CCryptoKeyStore::RemoveSproutViewingKey(vk)) {
        return false;
    }
    if (fFileBacked) {
        if (!CWalletDB(strWalletFile).EraseSproutViewingKey(vk)) {
            return false;
        }
    }

    return true;
}

bool CWallet::LoadSproutViewingKey(const libzcash::SproutViewingKey &vk)
{
    return CCryptoKeyStore::AddSproutViewingKey(vk);
}

bool CWallet::AddCScript(const CScript& redeemScript)
{
    if (!CCryptoKeyStore::AddCScript(redeemScript))
        return false;
    if (!fFileBacked)
        return true;
    return CWalletDB(strWalletFile).WriteCScript(Hash160(redeemScript), redeemScript);
}

bool CWallet::LoadCScript(const CScript& redeemScript)
{
    /* A sanity check was added in pull #3843 to avoid adding redeemScripts
     * that never can be redeemed. However, old wallets may still contain
     * these. Do not add them to the wallet and warn. */
    if (redeemScript.size() > MAX_SCRIPT_ELEMENT_SIZE)
    {
        std::string strAddr = EncodeDestination(CScriptID(redeemScript));
        LogPrintf("%s: Warning: This wallet contains a redeemScript of size %i which exceeds maximum size %i thus can never be redeemed. Do not use address %s.\n",
            __func__, redeemScript.size(), MAX_SCRIPT_ELEMENT_SIZE, strAddr);
        return true;
    }

    return CCryptoKeyStore::AddCScript(redeemScript);
}

bool CWallet::AddWatchOnly(const CScript &dest)
{
    if (!CCryptoKeyStore::AddWatchOnly(dest))
        return false;
    nTimeFirstKey = 1; // No birthday information for watch-only keys.
    NotifyWatchonlyChanged(true);
    if (!fFileBacked)
        return true;
    return CWalletDB(strWalletFile).WriteWatchOnly(dest);
}

bool CWallet::RemoveWatchOnly(const CScript &dest)
{
    AssertLockHeld(cs_wallet);
    if (!CCryptoKeyStore::RemoveWatchOnly(dest))
        return false;
    if (!HaveWatchOnly())
        NotifyWatchonlyChanged(false);
    if (fFileBacked)
        if (!CWalletDB(strWalletFile).EraseWatchOnly(dest))
            return false;

    return true;
}

bool CWallet::LoadWatchOnly(const CScript &dest)
{
    return CCryptoKeyStore::AddWatchOnly(dest);
}

bool CWallet::Unlock(const SecureString& strWalletPassphrase)
{
    CCrypter crypter;
    CKeyingMaterial vMasterKey;

    {
        LOCK(cs_wallet);
        BOOST_FOREACH(const MasterKeyMap::value_type& pMasterKey, mapMasterKeys)
        {
            if(!crypter.SetKeyFromPassphrase(strWalletPassphrase, pMasterKey.second.vchSalt, pMasterKey.second.nDeriveIterations, pMasterKey.second.nDerivationMethod))
                return false;
            if (!crypter.Decrypt(pMasterKey.second.vchCryptedKey, vMasterKey))
                continue; // try another master key
            if (CCryptoKeyStore::Unlock(vMasterKey))
                return true;
        }
    }
    return false;
}

bool CWallet::ChangeWalletPassphrase(const SecureString& strOldWalletPassphrase, const SecureString& strNewWalletPassphrase)
{
    bool fWasLocked = IsLocked();

    {
        LOCK(cs_wallet);
        Lock();

        CCrypter crypter;
        CKeyingMaterial vMasterKey;
        BOOST_FOREACH(MasterKeyMap::value_type& pMasterKey, mapMasterKeys)
        {
            if(!crypter.SetKeyFromPassphrase(strOldWalletPassphrase, pMasterKey.second.vchSalt, pMasterKey.second.nDeriveIterations, pMasterKey.second.nDerivationMethod))
                return false;
            if (!crypter.Decrypt(pMasterKey.second.vchCryptedKey, vMasterKey))
                return false;
            if (CCryptoKeyStore::Unlock(vMasterKey))
            {
                int64_t nStartTime = GetTimeMillis();
                crypter.SetKeyFromPassphrase(strNewWalletPassphrase, pMasterKey.second.vchSalt, pMasterKey.second.nDeriveIterations, pMasterKey.second.nDerivationMethod);
                pMasterKey.second.nDeriveIterations = pMasterKey.second.nDeriveIterations * (100 / ((double)(GetTimeMillis() - nStartTime)));

                nStartTime = GetTimeMillis();
                crypter.SetKeyFromPassphrase(strNewWalletPassphrase, pMasterKey.second.vchSalt, pMasterKey.second.nDeriveIterations, pMasterKey.second.nDerivationMethod);
                pMasterKey.second.nDeriveIterations = (pMasterKey.second.nDeriveIterations + pMasterKey.second.nDeriveIterations * 100 / ((double)(GetTimeMillis() - nStartTime))) / 2;

                if (pMasterKey.second.nDeriveIterations < 25000)
                    pMasterKey.second.nDeriveIterations = 25000;

                LogPrintf("Wallet passphrase changed to an nDeriveIterations of %i\n", pMasterKey.second.nDeriveIterations);

                if (!crypter.SetKeyFromPassphrase(strNewWalletPassphrase, pMasterKey.second.vchSalt, pMasterKey.second.nDeriveIterations, pMasterKey.second.nDerivationMethod))
                    return false;
                if (!crypter.Encrypt(vMasterKey, pMasterKey.second.vchCryptedKey))
                    return false;
                CWalletDB(strWalletFile).WriteMasterKey(pMasterKey.first, pMasterKey.second);
                if (fWasLocked)
                    Lock();
                return true;
            }
        }
    }

    return false;
}

void CWallet::ChainTip(const CBlockIndex *pindex, 
                       const CBlock *pblock,
                       SproutMerkleTree sproutTree,
                       SaplingMerkleTree saplingTree, 
                       bool added)
{
    if (added) {
        IncrementNoteWitnesses(pindex, pblock, sproutTree, saplingTree);
    } else {
        DecrementNoteWitnesses(pindex);
    }
}

void CWallet::SetBestChain(const CBlockLocator& loc)
{
    CWalletDB walletdb(strWalletFile);
    SetBestChainINTERNAL(walletdb, loc);
}

std::set<std::pair<libzcash::PaymentAddress, uint256>> CWallet::GetNullifiersForAddresses(const std::set<libzcash::PaymentAddress> & addresses)
{
    std::set<std::pair<libzcash::PaymentAddress, uint256>> nullifierSet;
    for (const auto & txPair : mapWallet) {
        for (const auto & noteDataPair : txPair.second.mapSproutNoteData) {
            if (noteDataPair.second.nullifier && addresses.count(noteDataPair.second.address)) {
                nullifierSet.insert(std::make_pair(noteDataPair.second.address, noteDataPair.second.nullifier.get()));
            }
        }
    }
    return nullifierSet;
}

bool CWallet::IsNoteChange(const std::set<std::pair<libzcash::PaymentAddress, uint256>> & nullifierSet, const PaymentAddress & address, const JSOutPoint & jsop)
{
    // A Note is marked as "change" if the address that received it
    // also spent Notes in the same transaction. This will catch,
    // for instance:
    // - Change created by spending fractions of Notes (because
    //   z_sendmany sends change to the originating z-address).
    // - "Chaining Notes" used to connect JoinSplits together.
    // - Notes created by consolidation transactions (e.g. using
    //   z_mergetoaddress).
    // - Notes sent from one address to itself.
    for (const JSDescription & jsd : mapWallet[jsop.hash].vjoinsplit) {
        for (const uint256 & nullifier : jsd.nullifiers) {
            if (nullifierSet.count(std::make_pair(address, nullifier))) {
                return true;
            }
        }
    }
    return false;
}

bool CWallet::SetMinVersion(enum WalletFeature nVersion, CWalletDB* pwalletdbIn, bool fExplicit)
{
    LOCK(cs_wallet); // nWalletVersion
    if (nWalletVersion >= nVersion)
        return true;

    // when doing an explicit upgrade, if we pass the max version permitted, upgrade all the way
    if (fExplicit && nVersion > nWalletMaxVersion)
            nVersion = FEATURE_LATEST;

    nWalletVersion = nVersion;

    if (nVersion > nWalletMaxVersion)
        nWalletMaxVersion = nVersion;

    if (fFileBacked)
    {
        CWalletDB* pwalletdb = pwalletdbIn ? pwalletdbIn : new CWalletDB(strWalletFile);
        if (nWalletVersion > 40000)
            pwalletdb->WriteMinVersion(nWalletVersion);
        if (!pwalletdbIn)
            delete pwalletdb;
    }

    return true;
}

bool CWallet::SetMaxVersion(int nVersion)
{
    LOCK(cs_wallet); // nWalletVersion, nWalletMaxVersion
    // cannot downgrade below current version
    if (nWalletVersion > nVersion)
        return false;

    nWalletMaxVersion = nVersion;

    return true;
}

set<uint256> CWallet::GetConflicts(const uint256& txid) const
{
    set<uint256> result;
    AssertLockHeld(cs_wallet);

    std::map<uint256, CWalletTx>::const_iterator it = mapWallet.find(txid);
    if (it == mapWallet.end())
        return result;
    const CWalletTx& wtx = it->second;

    std::pair<TxSpends::const_iterator, TxSpends::const_iterator> range;

    BOOST_FOREACH(const CTxIn& txin, wtx.vin)
    {
        if (mapTxSpends.count(txin.prevout) <= 1)
            continue;  // No conflict if zero or one spends
        range = mapTxSpends.equal_range(txin.prevout);
        for (TxSpends::const_iterator it = range.first; it != range.second; ++it)
            result.insert(it->second);
    }

    std::pair<TxNullifiers::const_iterator, TxNullifiers::const_iterator> range_n;

    for (const JSDescription& jsdesc : wtx.vjoinsplit) {
        for (const uint256& nullifier : jsdesc.nullifiers) {
            if (mapTxSproutNullifiers.count(nullifier) <= 1) {
                continue;  // No conflict if zero or one spends
            }
            range_n = mapTxSproutNullifiers.equal_range(nullifier);
            for (TxNullifiers::const_iterator it = range_n.first; it != range_n.second; ++it) {
                result.insert(it->second);
            }
        }
    }
    return result;
}

void CWallet::Flush(bool shutdown)
{
    bitdb.Flush(shutdown);
}

bool CWallet::Verify(const string& walletFile, string& warningString, string& errorString)
{
    if (!bitdb.Open(GetDataDir()))
    {
        // try moving the database env out of the way
        boost::filesystem::path pathDatabase = GetDataDir() / "database";
        boost::filesystem::path pathDatabaseBak = GetDataDir() / strprintf("database.%d.bak", GetTime());
        try {
            boost::filesystem::rename(pathDatabase, pathDatabaseBak);
            LogPrintf("Moved old %s to %s. Retrying.\n", pathDatabase.string(), pathDatabaseBak.string());
        } catch (const boost::filesystem::filesystem_error&) {
            // failure is ok (well, not really, but it's not worse than what we started with)
        }

        // try again
        if (!bitdb.Open(GetDataDir())) {
            // if it still fails, it probably means we can't even create the database env
            string msg = strprintf(_("Error initializing wallet database environment %s!"), GetDataDir());
            errorString += msg;
            return true;
        }
    }

    if (GetBoolArg("-salvagewallet", false))
    {
        // Recover readable keypairs:
        if (!CWalletDB::Recover(bitdb, walletFile, true))
            return false;
    }

    if (boost::filesystem::exists(GetDataDir() / walletFile))
    {
        CDBEnv::VerifyResult r = bitdb.Verify(walletFile, CWalletDB::Recover);
        if (r == CDBEnv::RECOVER_OK)
        {
            warningString += strprintf(_("Warning: wallet.dat corrupt, data salvaged!"
                                     " Original wallet.dat saved as wallet.{timestamp}.bak in %s; if"
                                     " your balance or transactions are incorrect you should"
                                     " restore from a backup."), GetDataDir());
        }
        if (r == CDBEnv::RECOVER_FAIL)
            errorString += _("wallet.dat corrupt, salvage failed");
    }

    return true;
}

template <class T>
void CWallet::SyncMetaData(pair<typename TxSpendMap<T>::iterator, typename TxSpendMap<T>::iterator> range)
{
    // We want all the wallet transactions in range to have the same metadata as
    // the oldest (smallest nOrderPos).
    // So: find smallest nOrderPos:

    int nMinOrderPos = std::numeric_limits<int>::max();
    const CWalletTx* copyFrom = NULL;
    for (typename TxSpendMap<T>::iterator it = range.first; it != range.second; ++it)
    {
        const uint256& hash = it->second;
        int n = mapWallet[hash].nOrderPos;
        if (n < nMinOrderPos)
        {
            nMinOrderPos = n;
            copyFrom = &mapWallet[hash];
        }
    }
    // Now copy data from copyFrom to rest:
    for (typename TxSpendMap<T>::iterator it = range.first; it != range.second; ++it)
    {
        const uint256& hash = it->second;
        CWalletTx* copyTo = &mapWallet[hash];
        if (copyFrom == copyTo) continue;
        copyTo->mapValue = copyFrom->mapValue;
        // mapSproutNoteData not copied on purpose
        // (it is always set correctly for each CWalletTx)
        copyTo->vOrderForm = copyFrom->vOrderForm;
        // fTimeReceivedIsTxTime not copied on purpose
        // nTimeReceived not copied on purpose
        copyTo->nTimeSmart = copyFrom->nTimeSmart;
        copyTo->fFromMe = copyFrom->fFromMe;
        copyTo->strFromAccount = copyFrom->strFromAccount;
        // nOrderPos not copied on purpose
        // cached members not copied on purpose
    }
}

/**
 * Outpoint is spent if any non-conflicted transaction
 * spends it:
 */
bool CWallet::IsSpent(const uint256& hash, unsigned int n) const
{
    const COutPoint outpoint(hash, n);
    pair<TxSpends::const_iterator, TxSpends::const_iterator> range;
    range = mapTxSpends.equal_range(outpoint);

    for (TxSpends::const_iterator it = range.first; it != range.second; ++it)
    {
        const uint256& wtxid = it->second;
        std::map<uint256, CWalletTx>::const_iterator mit = mapWallet.find(wtxid);
        if (mit != mapWallet.end() && mit->second.GetDepthInMainChain() >= 0)
            return true; // Spent
    }
    return false;
}

/**
 * Note is spent if any non-conflicted transaction
 * spends it:
 */
bool CWallet::IsSpent(const uint256& nullifier) const
{
    pair<TxNullifiers::const_iterator, TxNullifiers::const_iterator> range;
    range = mapTxSproutNullifiers.equal_range(nullifier);

    for (TxNullifiers::const_iterator it = range.first; it != range.second; ++it) {
        const uint256& wtxid = it->second;
        std::map<uint256, CWalletTx>::const_iterator mit = mapWallet.find(wtxid);
        if (mit != mapWallet.end() && mit->second.GetDepthInMainChain() >= 0) {
            return true; // Spent
        }
    }
    return false;
}

void CWallet::AddToTransparentSpends(const COutPoint& outpoint, const uint256& wtxid)
{
    mapTxSpends.insert(make_pair(outpoint, wtxid));

    pair<TxSpends::iterator, TxSpends::iterator> range;
    range = mapTxSpends.equal_range(outpoint);
    SyncMetaData<COutPoint>(range);
}

void CWallet::AddToSproutSpends(const uint256& nullifier, const uint256& wtxid)
{
    mapTxSproutNullifiers.insert(make_pair(nullifier, wtxid));

    pair<TxNullifiers::iterator, TxNullifiers::iterator> range;
    range = mapTxSproutNullifiers.equal_range(nullifier);
    SyncMetaData<uint256>(range);
}

void CWallet::AddToSpends(const uint256& wtxid)
{
    assert(mapWallet.count(wtxid));
    CWalletTx& thisTx = mapWallet[wtxid];
    if (thisTx.IsCoinBase()) // Coinbases don't spend anything!
        return;

    for (const CTxIn& txin : thisTx.vin) {
        AddToTransparentSpends(txin.prevout, wtxid);
    }
    for (const JSDescription& jsdesc : thisTx.vjoinsplit) {
        for (const uint256& nullifier : jsdesc.nullifiers) {
            AddToSproutSpends(nullifier, wtxid);
        }
    }
    for (const SpendDescription &spend : thisTx.vShieldedSpend) {
        AddToSaplingSpends(spend.nullifier, wtxid);
    }
}

void CWallet::AddToSaplingSpends(const uint256& nullifier, const uint256& wtxid)
{
    mapTxSaplingNullifiers.insert(make_pair(nullifier, wtxid));

    pair<TxNullifiers::iterator, TxNullifiers::iterator> range;
    range = mapTxSaplingNullifiers.equal_range(nullifier);
    SyncMetaData<uint256>(range);
}

void CWallet::ClearNoteWitnessCache()
{
    LOCK(cs_wallet);
    for (std::pair<const uint256, CWalletTx>& wtxItem : mapWallet) {
        for (mapSproutNoteData_t::value_type& item : wtxItem.second.mapSproutNoteData) {
            item.second.witnesses.clear();
            item.second.witnessHeight = -1;
        }
        for (mapSaplingNoteData_t::value_type& item : wtxItem.second.mapSaplingNoteData) {
            item.second.witnesses.clear();
            item.second.witnessHeight = -1;
        }
    }
    nWitnessCacheSize = 0;
}

template<typename NoteDataMap>
void CopyPreviousWitnesses(NoteDataMap& noteDataMap, int indexHeight, int64_t nWitnessCacheSize)
{
    for (auto& item : noteDataMap) {
        auto* nd = &(item.second);
        // Only increment witnesses that are behind the current height
        if (nd->witnessHeight < indexHeight) {
            // Check the validity of the cache
            // The only time a note witnessed above the current height
            // would be invalid here is during a reindex when blocks
            // have been decremented, and we are incrementing the blocks
            // immediately after.
            assert(nWitnessCacheSize >= nd->witnesses.size());
            // Witnesses being incremented should always be either -1
            // (never incremented or decremented) or one below indexHeight
            assert((nd->witnessHeight == -1) || (nd->witnessHeight == indexHeight - 1));
            // Copy the witness for the previous block if we have one
            if (nd->witnesses.size() > 0) {
                nd->witnesses.push_front(nd->witnesses.front());
            }
            if (nd->witnesses.size() > WITNESS_CACHE_SIZE) {
                nd->witnesses.pop_back();
            }
        }
    }
}

template<typename NoteDataMap>
void AppendNoteCommitment(NoteDataMap& noteDataMap, int indexHeight, int64_t nWitnessCacheSize, const uint256& note_commitment)
{
    for (auto& item : noteDataMap) {
        auto* nd = &(item.second);
        if (nd->witnessHeight < indexHeight && nd->witnesses.size() > 0) {
            // Check the validity of the cache
            // See comment in CopyPreviousWitnesses about validity.
            assert(nWitnessCacheSize >= nd->witnesses.size());
            nd->witnesses.front().append(note_commitment);
        }
    }
}

template<typename OutPoint, typename NoteData, typename Witness>
void WitnessNoteIfMine(std::map<OutPoint, NoteData>& noteDataMap, int indexHeight, int64_t nWitnessCacheSize, const OutPoint& key, const Witness& witness)
{
    if (noteDataMap.count(key) && noteDataMap[key].witnessHeight < indexHeight) {
        auto* nd = &(noteDataMap[key]);
        if (nd->witnesses.size() > 0) {
            // We think this can happen because we write out the
            // witness cache state after every block increment or
            // decrement, but the block index itself is written in
            // batches. So if the node crashes in between these two
            // operations, it is possible for IncrementNoteWitnesses
            // to be called again on previously-cached blocks. This
            // doesn't affect existing cached notes because of the
            // NoteData::witnessHeight checks. See #1378 for details.
            LogPrintf("Inconsistent witness cache state found for %s\n- Cache size: %d\n- Top (height %d): %s\n- New (height %d): %s\n",
                        key.ToString(), nd->witnesses.size(),
                        nd->witnessHeight,
                        nd->witnesses.front().root().GetHex(),
                        indexHeight,
                        witness.root().GetHex());
            nd->witnesses.clear();
        }
        nd->witnesses.push_front(witness);
        // Set height to one less than pindex so it gets incremented
        nd->witnessHeight = indexHeight - 1;
        // Check the validity of the cache
        assert(nWitnessCacheSize >= nd->witnesses.size());
    }
}


template<typename NoteDataMap>
void UpdateWitnessHeights(NoteDataMap& noteDataMap, int indexHeight, int64_t nWitnessCacheSize)
{
    for (auto& item : noteDataMap) {
        auto* nd = &(item.second);
        if (nd->witnessHeight < indexHeight) {
            nd->witnessHeight = indexHeight;
            // Check the validity of the cache
            // See comment in CopyPreviousWitnesses about validity.
            assert(nWitnessCacheSize >= nd->witnesses.size());
        }
    }
}

void CWallet::IncrementNoteWitnesses(const CBlockIndex* pindex,
                                     const CBlock* pblockIn,
                                     SproutMerkleTree& sproutTree,
                                     SaplingMerkleTree& saplingTree)
{
    LOCK(cs_wallet);
    for (std::pair<const uint256, CWalletTx>& wtxItem : mapWallet) {
       ::CopyPreviousWitnesses(wtxItem.second.mapSproutNoteData, pindex->nHeight, nWitnessCacheSize);
       ::CopyPreviousWitnesses(wtxItem.second.mapSaplingNoteData, pindex->nHeight, nWitnessCacheSize);
    }

    if (nWitnessCacheSize < WITNESS_CACHE_SIZE) {
        nWitnessCacheSize += 1;
    }

    const CBlock* pblock {pblockIn};
    CBlock block;
    if (!pblock) {
        ReadBlockFromDisk(block, pindex);
        pblock = &block;
    }

    for (const CTransaction& tx : pblock->vtx) {
        auto hash = tx.GetHash();
        bool txIsOurs = mapWallet.count(hash);
        // Sprout
        for (size_t i = 0; i < tx.vjoinsplit.size(); i++) {
            const JSDescription& jsdesc = tx.vjoinsplit[i];
            for (uint8_t j = 0; j < jsdesc.commitments.size(); j++) {
                const uint256& note_commitment = jsdesc.commitments[j];
                sproutTree.append(note_commitment);

                // Increment existing witnesses
                for (std::pair<const uint256, CWalletTx>& wtxItem : mapWallet) {
                    ::AppendNoteCommitment(wtxItem.second.mapSproutNoteData, pindex->nHeight, nWitnessCacheSize, note_commitment);
                }

                // If this is our note, witness it
                if (txIsOurs) {
                    JSOutPoint jsoutpt {hash, i, j};
                    ::WitnessNoteIfMine(mapWallet[hash].mapSproutNoteData, pindex->nHeight, nWitnessCacheSize, jsoutpt, sproutTree.witness());
                }
            }
        }
        // Sapling
        for (uint32_t i = 0; i < tx.vShieldedOutput.size(); i++) {
            const uint256& note_commitment = tx.vShieldedOutput[i].cm;
            saplingTree.append(note_commitment);

            // Increment existing witnesses
            for (std::pair<const uint256, CWalletTx>& wtxItem : mapWallet) {
                ::AppendNoteCommitment(wtxItem.second.mapSaplingNoteData, pindex->nHeight, nWitnessCacheSize, note_commitment);
            }

            // If this is our note, witness it
            if (txIsOurs) {
                SaplingOutPoint outPoint {hash, i};
                ::WitnessNoteIfMine(mapWallet[hash].mapSaplingNoteData, pindex->nHeight, nWitnessCacheSize, outPoint, saplingTree.witness());
            }
        }
    }

    // Update witness heights
    for (std::pair<const uint256, CWalletTx>& wtxItem : mapWallet) {
        ::UpdateWitnessHeights(wtxItem.second.mapSproutNoteData, pindex->nHeight, nWitnessCacheSize);
        ::UpdateWitnessHeights(wtxItem.second.mapSaplingNoteData, pindex->nHeight, nWitnessCacheSize);
    }

    // For performance reasons, we write out the witness cache in
    // CWallet::SetBestChain() (which also ensures that overall consistency
    // of the wallet.dat is maintained).
}

template<typename NoteDataMap>
void DecrementNoteWitnesses(NoteDataMap& noteDataMap, int indexHeight, int64_t nWitnessCacheSize)
{
    for (auto& item : noteDataMap) {
        auto* nd = &(item.second);
        // Only decrement witnesses that are not above the current height
        if (nd->witnessHeight <= indexHeight) {
            // Check the validity of the cache
            // See comment below (this would be invalid if there were a
            // prior decrement).
            assert(nWitnessCacheSize >= nd->witnesses.size());
            // Witnesses being decremented should always be either -1
            // (never incremented or decremented) or equal to the height
            // of the block being removed (indexHeight)
            assert((nd->witnessHeight == -1) || (nd->witnessHeight == indexHeight));
            if (nd->witnesses.size() > 0) {
                nd->witnesses.pop_front();
            }
            // indexHeight is the height of the block being removed, so 
            // the new witness cache height is one below it.
            nd->witnessHeight = indexHeight - 1;
        }
        // Check the validity of the cache
        // Technically if there are notes witnessed above the current
        // height, their cache will now be invalid (relative to the new
        // value of nWitnessCacheSize). However, this would only occur
        // during a reindex, and by the time the reindex reaches the tip
        // of the chain again, the existing witness caches will be valid
        // again.
        // We don't set nWitnessCacheSize to zero at the start of the
        // reindex because the on-disk blocks had already resulted in a
        // chain that didn't trigger the assertion below.
        if (nd->witnessHeight < indexHeight) {
            // Subtract 1 to compare to what nWitnessCacheSize will be after
            // decrementing.
            assert((nWitnessCacheSize - 1) >= nd->witnesses.size());
        }
    }
}

void CWallet::DecrementNoteWitnesses(const CBlockIndex* pindex)
{
    LOCK(cs_wallet);
    for (std::pair<const uint256, CWalletTx>& wtxItem : mapWallet) {
        ::DecrementNoteWitnesses(wtxItem.second.mapSproutNoteData, pindex->nHeight, nWitnessCacheSize);
        ::DecrementNoteWitnesses(wtxItem.second.mapSaplingNoteData, pindex->nHeight, nWitnessCacheSize);
    }
    nWitnessCacheSize -= 1;
    // TODO: If nWitnessCache is zero, we need to regenerate the caches (#1302)
    assert(nWitnessCacheSize > 0);

    // For performance reasons, we write out the witness cache in
    // CWallet::SetBestChain() (which also ensures that overall consistency
    // of the wallet.dat is maintained).
}

bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
{
    if (IsCrypted())
        return false;

    CKeyingMaterial vMasterKey;

    vMasterKey.resize(WALLET_CRYPTO_KEY_SIZE);
    GetRandBytes(&vMasterKey[0], WALLET_CRYPTO_KEY_SIZE);

    CMasterKey kMasterKey;

    kMasterKey.vchSalt.resize(WALLET_CRYPTO_SALT_SIZE);
    GetRandBytes(&kMasterKey.vchSalt[0], WALLET_CRYPTO_SALT_SIZE);

    CCrypter crypter;
    int64_t nStartTime = GetTimeMillis();
    crypter.SetKeyFromPassphrase(strWalletPassphrase, kMasterKey.vchSalt, 25000, kMasterKey.nDerivationMethod);
    kMasterKey.nDeriveIterations = 2500000 / ((double)(GetTimeMillis() - nStartTime));

    nStartTime = GetTimeMillis();
    crypter.SetKeyFromPassphrase(strWalletPassphrase, kMasterKey.vchSalt, kMasterKey.nDeriveIterations, kMasterKey.nDerivationMethod);
    kMasterKey.nDeriveIterations = (kMasterKey.nDeriveIterations + kMasterKey.nDeriveIterations * 100 / ((double)(GetTimeMillis() - nStartTime))) / 2;

    if (kMasterKey.nDeriveIterations < 25000)
        kMasterKey.nDeriveIterations = 25000;

    LogPrintf("Encrypting Wallet with an nDeriveIterations of %i\n", kMasterKey.nDeriveIterations);

    if (!crypter.SetKeyFromPassphrase(strWalletPassphrase, kMasterKey.vchSalt, kMasterKey.nDeriveIterations, kMasterKey.nDerivationMethod))
        return false;
    if (!crypter.Encrypt(vMasterKey, kMasterKey.vchCryptedKey))
        return false;

    {
        LOCK(cs_wallet);
        mapMasterKeys[++nMasterKeyMaxID] = kMasterKey;
        if (fFileBacked)
        {
            assert(!pwalletdbEncryption);
            pwalletdbEncryption = new CWalletDB(strWalletFile);
            if (!pwalletdbEncryption->TxnBegin()) {
                delete pwalletdbEncryption;
                pwalletdbEncryption = NULL;
                return false;
            }
            pwalletdbEncryption->WriteMasterKey(nMasterKeyMaxID, kMasterKey);
        }

        if (!EncryptKeys(vMasterKey))
        {
            if (fFileBacked) {
                pwalletdbEncryption->TxnAbort();
                delete pwalletdbEncryption;
            }
            // We now probably have half of our keys encrypted in memory, and half not...
            // die and let the user reload the unencrypted wallet.
            assert(false);
        }

        // Encryption was introduced in version 0.4.0
        SetMinVersion(FEATURE_WALLETCRYPT, pwalletdbEncryption, true);

        if (fFileBacked)
        {
            if (!pwalletdbEncryption->TxnCommit()) {
                delete pwalletdbEncryption;
                // We now have keys encrypted in memory, but not on disk...
                // die to avoid confusion and let the user reload the unencrypted wallet.
                assert(false);
            }

            delete pwalletdbEncryption;
            pwalletdbEncryption = NULL;
        }

        Lock();
        Unlock(strWalletPassphrase);
        NewKeyPool();
        Lock();

        // Need to completely rewrite the wallet file; if we don't, bdb might keep
        // bits of the unencrypted private key in slack space in the database file.
        CDB::Rewrite(strWalletFile);

    }
    NotifyStatusChanged(this);

    return true;
}

int64_t CWallet::IncOrderPosNext(CWalletDB *pwalletdb)
{
    AssertLockHeld(cs_wallet); // nOrderPosNext
    int64_t nRet = nOrderPosNext++;
    if (pwalletdb) {
        pwalletdb->WriteOrderPosNext(nOrderPosNext);
    } else {
        CWalletDB(strWalletFile).WriteOrderPosNext(nOrderPosNext);
    }
    return nRet;
}

CWallet::TxItems CWallet::OrderedTxItems(std::list<CAccountingEntry>& acentries, std::string strAccount)
{
    AssertLockHeld(cs_wallet); // mapWallet
    CWalletDB walletdb(strWalletFile);

    // First: get all CWalletTx and CAccountingEntry into a sorted-by-order multimap.
    TxItems txOrdered;

    // Note: maintaining indices in the database of (account,time) --> txid and (account, time) --> acentry
    // would make this much faster for applications that do this a lot.
    for (map<uint256, CWalletTx>::iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
    {
        CWalletTx* wtx = &((*it).second);
        txOrdered.insert(make_pair(wtx->nOrderPos, TxPair(wtx, (CAccountingEntry*)0)));
    }
    acentries.clear();
    walletdb.ListAccountCreditDebit(strAccount, acentries);
    BOOST_FOREACH(CAccountingEntry& entry, acentries)
    {
        txOrdered.insert(make_pair(entry.nOrderPos, TxPair((CWalletTx*)0, &entry)));
    }

    return txOrdered;
}

void CWallet::MarkDirty()
{
    {
        LOCK(cs_wallet);
        BOOST_FOREACH(PAIRTYPE(const uint256, CWalletTx)& item, mapWallet)
            item.second.MarkDirty();
    }
}

/**
 * Ensure that every note in the wallet (for which we possess a spending key)
 * has a cached nullifier.
 */
bool CWallet::UpdateNullifierNoteMap()
{
    {
        LOCK(cs_wallet);

        if (IsLocked())
            return false;

        ZCNoteDecryption dec;
        for (std::pair<const uint256, CWalletTx>& wtxItem : mapWallet) {
            for (mapSproutNoteData_t::value_type& item : wtxItem.second.mapSproutNoteData) {
                if (!item.second.nullifier) {
                    if (GetNoteDecryptor(item.second.address, dec)) {
                        auto i = item.first.js;
                        auto hSig = wtxItem.second.vjoinsplit[i].h_sig(
                            *pzcashParams, wtxItem.second.joinSplitPubKey);
                        item.second.nullifier = GetSproutNoteNullifier(
                            wtxItem.second.vjoinsplit[i],
                            item.second.address,
                            dec,
                            hSig,
                            item.first.n);
                    }
                }
            }
            UpdateNullifierNoteMapWithTx(wtxItem.second);
        }
    }
    return true;
}

/**
 * Update mapSproutNullifiersToNotes with the cached nullifiers in this tx.
 */
void CWallet::UpdateNullifierNoteMapWithTx(const CWalletTx& wtx)
{
    {
        LOCK(cs_wallet);
        for (const mapSproutNoteData_t::value_type& item : wtx.mapSproutNoteData) {
            if (item.second.nullifier) {
                mapSproutNullifiersToNotes[*item.second.nullifier] = item.first;
            }
        }
    }
}

bool CWallet::AddToWallet(const CWalletTx& wtxIn, bool fFromLoadWallet, CWalletDB* pwalletdb)
{
    uint256 hash = wtxIn.GetHash();

    if (fFromLoadWallet)
    {
        mapWallet[hash] = wtxIn;
        mapWallet[hash].BindWallet(this);
        UpdateNullifierNoteMapWithTx(mapWallet[hash]);
        AddToSpends(hash);
    }
    else
    {
        LOCK(cs_wallet);
        // Inserts only if not already there, returns tx inserted or tx found
        pair<map<uint256, CWalletTx>::iterator, bool> ret = mapWallet.insert(make_pair(hash, wtxIn));
        CWalletTx& wtx = (*ret.first).second;
        wtx.BindWallet(this);
        UpdateNullifierNoteMapWithTx(wtx);
        bool fInsertedNew = ret.second;
        if (fInsertedNew)
        {
            wtx.nTimeReceived = GetAdjustedTime();
            wtx.nOrderPos = IncOrderPosNext(pwalletdb);

            wtx.nTimeSmart = wtx.nTimeReceived;
            if (!wtxIn.hashBlock.IsNull())
            {
                if (mapBlockIndex.count(wtxIn.hashBlock))
                {
                    int64_t latestNow = wtx.nTimeReceived;
                    int64_t latestEntry = 0;
                    {
                        // Tolerate times up to the last timestamp in the wallet not more than 5 minutes into the future
                        int64_t latestTolerated = latestNow + 300;
                        std::list<CAccountingEntry> acentries;
                        TxItems txOrdered = OrderedTxItems(acentries);
                        for (TxItems::reverse_iterator it = txOrdered.rbegin(); it != txOrdered.rend(); ++it)
                        {
                            CWalletTx *const pwtx = (*it).second.first;
                            if (pwtx == &wtx)
                                continue;
                            CAccountingEntry *const pacentry = (*it).second.second;
                            int64_t nSmartTime;
                            if (pwtx)
                            {
                                nSmartTime = pwtx->nTimeSmart;
                                if (!nSmartTime)
                                    nSmartTime = pwtx->nTimeReceived;
                            }
                            else
                                nSmartTime = pacentry->nTime;
                            if (nSmartTime <= latestTolerated)
                            {
                                latestEntry = nSmartTime;
                                if (nSmartTime > latestNow)
                                    latestNow = nSmartTime;
                                break;
                            }
                        }
                    }

                    int64_t blocktime = mapBlockIndex[wtxIn.hashBlock]->GetBlockTime();
                    wtx.nTimeSmart = std::max(latestEntry, std::min(blocktime, latestNow));
                }
                else
                    LogPrintf("AddToWallet(): found %s in block %s not in index\n",
                             wtxIn.GetHash().ToString(),
                             wtxIn.hashBlock.ToString());
            }
            AddToSpends(hash);
        }

        bool fUpdated = false;
        if (!fInsertedNew)
        {
            // Merge
            if (!wtxIn.hashBlock.IsNull() && wtxIn.hashBlock != wtx.hashBlock)
            {
                wtx.hashBlock = wtxIn.hashBlock;
                fUpdated = true;
            }
            if (wtxIn.nIndex != -1 && (wtxIn.vMerkleBranch != wtx.vMerkleBranch || wtxIn.nIndex != wtx.nIndex))
            {
                wtx.vMerkleBranch = wtxIn.vMerkleBranch;
                wtx.nIndex = wtxIn.nIndex;
                fUpdated = true;
            }
            if (UpdatedNoteData(wtxIn, wtx)) {
                fUpdated = true;
            }
            if (wtxIn.fFromMe && wtxIn.fFromMe != wtx.fFromMe)
            {
                wtx.fFromMe = wtxIn.fFromMe;
                fUpdated = true;
            }
        }

        //// debug print
        LogPrintf("AddToWallet %s  %s%s\n", wtxIn.GetHash().ToString(), (fInsertedNew ? "new" : ""), (fUpdated ? "update" : ""));

        // Write to disk
        if (fInsertedNew || fUpdated)
            if (!wtx.WriteToDisk(pwalletdb))
                return false;

        // Break debit/credit balance caches:
        wtx.MarkDirty();

        // Notify UI of new or updated transaction
        NotifyTransactionChanged(this, hash, fInsertedNew ? CT_NEW : CT_UPDATED);

        // notify an external script when a wallet transaction comes in or is updated
        std::string strCmd = GetArg("-walletnotify", "");

        if ( !strCmd.empty())
        {
            boost::replace_all(strCmd, "%s", wtxIn.GetHash().GetHex());
            boost::thread t(runCommand, strCmd); // thread runs free
        }

    }
    return true;
}

bool CWallet::UpdatedNoteData(const CWalletTx& wtxIn, CWalletTx& wtx)
{
    bool unchangedSproutFlag = (wtxIn.mapSproutNoteData.empty() || wtxIn.mapSproutNoteData == wtx.mapSproutNoteData);
    if (!unchangedSproutFlag) {
        auto tmp = wtxIn.mapSproutNoteData;
        // Ensure we keep any cached witnesses we may already have
        for (const std::pair <JSOutPoint, SproutNoteData> nd : wtx.mapSproutNoteData) {
            if (tmp.count(nd.first) && nd.second.witnesses.size() > 0) {
                tmp.at(nd.first).witnesses.assign(
                        nd.second.witnesses.cbegin(), nd.second.witnesses.cend());
            }
            tmp.at(nd.first).witnessHeight = nd.second.witnessHeight;
        }
        // Now copy over the updated note data
        wtx.mapSproutNoteData = tmp;
    }

    bool unchangedSaplingFlag = (wtxIn.mapSaplingNoteData.empty() || wtxIn.mapSaplingNoteData == wtx.mapSaplingNoteData);
    if (!unchangedSaplingFlag) {
        auto tmp = wtxIn.mapSaplingNoteData;
        // Ensure we keep any cached witnesses we may already have

        for (const std::pair <SaplingOutPoint, SaplingNoteData> nd : wtx.mapSaplingNoteData) {
            if (tmp.count(nd.first) && nd.second.witnesses.size() > 0) {
                tmp.at(nd.first).witnesses.assign(
                        nd.second.witnesses.cbegin(), nd.second.witnesses.cend());
            }
            tmp.at(nd.first).witnessHeight = nd.second.witnessHeight;
        }

        // Now copy over the updated note data
        wtx.mapSaplingNoteData = tmp;
    }

    return !unchangedSproutFlag || !unchangedSaplingFlag;
}

/**
 * Add a transaction to the wallet, or update it.
 * pblock is optional, but should be provided if the transaction is known to be in a block.
 * If fUpdate is true, existing transactions will be updated.
 */
bool CWallet::AddToWalletIfInvolvingMe(const CTransaction& tx, const CBlock* pblock, bool fUpdate)
{
    {
        AssertLockHeld(cs_wallet);
        bool fExisted = mapWallet.count(tx.GetHash()) != 0;
        if (fExisted && !fUpdate) return false;
        auto sproutNoteData = FindMySproutNotes(tx);
        auto saplingNoteData = FindMySaplingNotes(tx);
        if (fExisted || IsMine(tx) || IsFromMe(tx) || sproutNoteData.size() > 0 || saplingNoteData.size() > 0)
        {
            CWalletTx wtx(this,tx);

            if (sproutNoteData.size() > 0) {
                wtx.SetSproutNoteData(sproutNoteData);
            }

            if (saplingNoteData.size() > 0) {
                wtx.SetSaplingNoteData(saplingNoteData);
            }

            // Get merkle branch if transaction was found in a block
            if (pblock)
                wtx.SetMerkleBranch(*pblock);

            // Do not flush the wallet here for performance reasons
            // this is safe, as in case of a crash, we rescan the necessary blocks on startup through our SetBestChain-mechanism
            CWalletDB walletdb(strWalletFile, "r+", false);

            return AddToWallet(wtx, false, &walletdb);
        }
    }
    return false;
}

void CWallet::SyncTransaction(const CTransaction& tx, const CBlock* pblock)
{
    LOCK2(cs_main, cs_wallet);
    if (!AddToWalletIfInvolvingMe(tx, pblock, true))
        return; // Not one of ours

    MarkAffectedTransactionsDirty(tx);
}

void CWallet::MarkAffectedTransactionsDirty(const CTransaction& tx)
{
    // If a transaction changes 'conflicted' state, that changes the balance
    // available of the outputs it spends. So force those to be
    // recomputed, also:
    BOOST_FOREACH(const CTxIn& txin, tx.vin)
    {
        if (mapWallet.count(txin.prevout.hash))
            mapWallet[txin.prevout.hash].MarkDirty();
    }
    for (const JSDescription& jsdesc : tx.vjoinsplit) {
        for (const uint256& nullifier : jsdesc.nullifiers) {
            if (mapSproutNullifiersToNotes.count(nullifier) &&
                mapWallet.count(mapSproutNullifiersToNotes[nullifier].hash)) {
                mapWallet[mapSproutNullifiersToNotes[nullifier].hash].MarkDirty();
            }
        }
    }

    for (const SpendDescription &spend : tx.vShieldedSpend) {
        uint256 nullifier = spend.nullifier;
        if (mapSaplingNullifiersToNotes.count(nullifier) &&
            mapWallet.count(mapSaplingNullifiersToNotes[nullifier].hash)) {
            mapWallet[mapSaplingNullifiersToNotes[nullifier].hash].MarkDirty();
        }
    }
}

void CWallet::EraseFromWallet(const uint256 &hash)
{
    if (!fFileBacked)
        return;
    {
        LOCK(cs_wallet);
        if (mapWallet.erase(hash))
            CWalletDB(strWalletFile).EraseTx(hash);
    }
    return;
}


/**
 * Returns a nullifier if the SpendingKey is available
 * Throws std::runtime_error if the decryptor doesn't match this note
 */
boost::optional<uint256> CWallet::GetSproutNoteNullifier(const JSDescription &jsdesc,
                                                         const libzcash::SproutPaymentAddress &address,
                                                         const ZCNoteDecryption &dec,
                                                         const uint256 &hSig,
                                                         uint8_t n) const
{
    boost::optional<uint256> ret;
    auto note_pt = libzcash::SproutNotePlaintext::decrypt(
        dec,
        jsdesc.ciphertexts[n],
        jsdesc.ephemeralKey,
        hSig,
        (unsigned char) n);
    auto note = note_pt.note(address);
    // SpendingKeys are only available if:
    // - We have them (this isn't a viewing key)
    // - The wallet is unlocked
    libzcash::SproutSpendingKey key;
    if (GetSproutSpendingKey(address, key)) {
        ret = note.nullifier(key);
    }
    return ret;
}

/**
 * Finds all output notes in the given transaction that have been sent to
 * PaymentAddresses in this wallet.
 *
 * It should never be necessary to call this method with a CWalletTx, because
 * the result of FindMySproutNotes (for the addresses available at the time) will
 * already have been cached in CWalletTx.mapSproutNoteData.
 */
mapSproutNoteData_t CWallet::FindMySproutNotes(const CTransaction &tx) const
{
    LOCK(cs_SpendingKeyStore);
    uint256 hash = tx.GetHash();

    mapSproutNoteData_t noteData;
    for (size_t i = 0; i < tx.vjoinsplit.size(); i++) {
        auto hSig = tx.vjoinsplit[i].h_sig(*pzcashParams, tx.joinSplitPubKey);
        for (uint8_t j = 0; j < tx.vjoinsplit[i].ciphertexts.size(); j++) {
            for (const NoteDecryptorMap::value_type& item : mapNoteDecryptors) {
                try {
                    auto address = item.first;
                    JSOutPoint jsoutpt {hash, i, j};
                    auto nullifier = GetSproutNoteNullifier(
                        tx.vjoinsplit[i],
                        address,
                        item.second,
                        hSig, j);
                    if (nullifier) {
                        SproutNoteData nd {address, *nullifier};
                        noteData.insert(std::make_pair(jsoutpt, nd));
                    } else {
                        SproutNoteData nd {address};
                        noteData.insert(std::make_pair(jsoutpt, nd));
                    }
                    break;
                } catch (const note_decryption_failed &err) {
                    // Couldn't decrypt with this decryptor
                } catch (const std::exception &exc) {
                    // Unexpected failure
                    LogPrintf("FindMySproutNotes(): Unexpected error while testing decrypt:\n");
                    LogPrintf("%s\n", exc.what());
                }
            }
        }
    }
    return noteData;
}


/**
 * Finds all output notes in the given transaction that have been sent to
 * SaplingPaymentAddresses in this wallet.
 *
 * It should never be necessary to call this method with a CWalletTx, because
 * the result of FindMySaplingNotes (for the addresses available at the time) will
 * already have been cached in CWalletTx.mapSaplingNoteData.
 */
mapSaplingNoteData_t CWallet::FindMySaplingNotes(const CTransaction &tx) const
{
    LOCK(cs_SpendingKeyStore);
    uint256 hash = tx.GetHash();

    mapSaplingNoteData_t noteData;

    // Protocol Spec: 4.19 Block Chain Scanning (Sapling)
    for (uint32_t i = 0; i < tx.vShieldedOutput.size(); ++i) {
        const OutputDescription output = tx.vShieldedOutput[i];
        for (auto it = mapSaplingIncomingViewingKeys.begin(); it != mapSaplingIncomingViewingKeys.end(); ++it) {
            SaplingIncomingViewingKey ivk = it->second;
            auto result = SaplingNotePlaintext::decrypt(output.encCiphertext, ivk, output.ephemeralKey, output.cm);
            if (!result) {
                continue;
            }
            // We don't cache the nullifier here as computing it requires knowledge of the note position
            // in the commitment tree, which can only be determined when the transaction has been mined.
            SaplingOutPoint op {hash, i};
            SaplingNoteData nd;
            nd.ivk = ivk;
            noteData.insert(std::make_pair(op, nd));
            break;
        }
    }

    return noteData;
}

bool CWallet::IsSproutNullifierFromMe(const uint256& nullifier) const
{
    {
        LOCK(cs_wallet);
        if (mapSproutNullifiersToNotes.count(nullifier) &&
                mapWallet.count(mapSproutNullifiersToNotes.at(nullifier).hash)) {
            return true;
        }
    }
    return false;
}

void CWallet::GetSproutNoteWitnesses(std::vector<JSOutPoint> notes,
                                     std::vector<boost::optional<SproutWitness>>& witnesses,
                                     uint256 &final_anchor)
{
    LOCK(cs_wallet);
    witnesses.resize(notes.size());
    boost::optional<uint256> rt;
    int i = 0;
    for (JSOutPoint note : notes) {
        if (mapWallet.count(note.hash) &&
                mapWallet[note.hash].mapSproutNoteData.count(note) &&
                mapWallet[note.hash].mapSproutNoteData[note].witnesses.size() > 0) {
            witnesses[i] = mapWallet[note.hash].mapSproutNoteData[note].witnesses.front();
            if (!rt) {
                rt = witnesses[i]->root();
            } else {
                assert(*rt == witnesses[i]->root());
            }
        }
        i++;
    }
    // All returned witnesses have the same anchor
    if (rt) {
        final_anchor = *rt;
    }
}

void CWallet::GetSaplingNoteWitnesses(std::vector<SaplingOutPoint> notes,
                                      std::vector<boost::optional<SaplingWitness>>& witnesses,
                                      uint256 &final_anchor)
{
    LOCK(cs_wallet);
    witnesses.resize(notes.size());
    boost::optional<uint256> rt;
    int i = 0;
    for (SaplingOutPoint note : notes) {
        if (mapWallet.count(note.hash) &&
                mapWallet[note.hash].mapSaplingNoteData.count(note) &&
                mapWallet[note.hash].mapSaplingNoteData[note].witnesses.size() > 0) {
            witnesses[i] = mapWallet[note.hash].mapSaplingNoteData[note].witnesses.front();
            if (!rt) {
                rt = witnesses[i]->root();
            } else {
                assert(*rt == witnesses[i]->root());
            }
        }
        i++;
    }
    // All returned witnesses have the same anchor
    if (rt) {
        final_anchor = *rt;
    }
}

isminetype CWallet::IsMine(const CTxIn &txin) const
{
    {
        LOCK(cs_wallet);
        map<uint256, CWalletTx>::const_iterator mi = mapWallet.find(txin.prevout.hash);
        if (mi != mapWallet.end())
        {
            const CWalletTx& prev = (*mi).second;
            if (txin.prevout.n < prev.vout.size())
                return IsMine(prev.vout[txin.prevout.n]);
        }
    }
    return ISMINE_NO;
}

CAmount CWallet::GetDebit(const CTxIn &txin, const isminefilter& filter) const
{
    {
        LOCK(cs_wallet);
        map<uint256, CWalletTx>::const_iterator mi = mapWallet.find(txin.prevout.hash);
        if (mi != mapWallet.end())
        {
            const CWalletTx& prev = (*mi).second;
            if (txin.prevout.n < prev.vout.size())
                if (IsMine(prev.vout[txin.prevout.n]) & filter)
                    return prev.vout[txin.prevout.n].nValue;
        }
    }
    return 0;
}

isminetype CWallet::IsMine(const CTxOut& txout) const
{
    return ::IsMine(*this, txout.scriptPubKey);
}

CAmount CWallet::GetCredit(const CTxOut& txout, const isminefilter& filter) const
{
    if (!MoneyRange(txout.nValue))
        throw std::runtime_error("CWallet::GetCredit(): value out of range");
    return ((IsMine(txout) & filter) ? txout.nValue : 0);
}

bool CWallet::IsChange(const CTxOut& txout) const
{
    // TODO: fix handling of 'change' outputs. The assumption is that any
    // payment to a script that is ours, but is not in the address book
    // is change. That assumption is likely to break when we implement multisignature
    // wallets that return change back into a multi-signature-protected address;
    // a better way of identifying which outputs are 'the send' and which are
    // 'the change' will need to be implemented (maybe extend CWalletTx to remember
    // which output, if any, was change).
    if (::IsMine(*this, txout.scriptPubKey))
    {
        CTxDestination address;
        if (!ExtractDestination(txout.scriptPubKey, address))
            return true;

        LOCK(cs_wallet);
        if (!mapAddressBook.count(address))
            return true;
    }
    return false;
}

CAmount CWallet::GetChange(const CTxOut& txout) const
{
    if (!MoneyRange(txout.nValue))
        throw std::runtime_error("CWallet::GetChange(): value out of range");
    return (IsChange(txout) ? txout.nValue : 0);
}

bool CWallet::IsMine(const CTransaction& tx) const
{
    BOOST_FOREACH(const CTxOut& txout, tx.vout)
        if (IsMine(txout))
            return true;
    return false;
}

bool CWallet::IsFromMe(const CTransaction& tx) const
{
    if (GetDebit(tx, ISMINE_ALL) > 0) {
        return true;
    }
    for (const JSDescription& jsdesc : tx.vjoinsplit) {
        for (const uint256& nullifier : jsdesc.nullifiers) {
            if (IsSproutNullifierFromMe(nullifier)) {
                return true;
            }
        }
    }
    return false;
}

CAmount CWallet::GetDebit(const CTransaction& tx, const isminefilter& filter) const
{
    CAmount nDebit = 0;
    BOOST_FOREACH(const CTxIn& txin, tx.vin)
    {
        nDebit += GetDebit(txin, filter);
        if (!MoneyRange(nDebit))
            throw std::runtime_error("CWallet::GetDebit(): value out of range");
    }
    return nDebit;
}

CAmount CWallet::GetCredit(const CTransaction& tx, const isminefilter& filter) const
{
    CAmount nCredit = 0;
    BOOST_FOREACH(const CTxOut& txout, tx.vout)
    {
        nCredit += GetCredit(txout, filter);
        if (!MoneyRange(nCredit))
            throw std::runtime_error("CWallet::GetCredit(): value out of range");
    }
    return nCredit;
}

CAmount CWallet::GetChange(const CTransaction& tx) const
{
    CAmount nChange = 0;
    BOOST_FOREACH(const CTxOut& txout, tx.vout)
    {
        nChange += GetChange(txout);
        if (!MoneyRange(nChange))
            throw std::runtime_error("CWallet::GetChange(): value out of range");
    }
    return nChange;
}

void CWalletTx::SetSproutNoteData(mapSproutNoteData_t &noteData)
{
    mapSproutNoteData.clear();
    for (const std::pair<JSOutPoint, SproutNoteData> nd : noteData) {
        if (nd.first.js < vjoinsplit.size() &&
                nd.first.n < vjoinsplit[nd.first.js].ciphertexts.size()) {
            // Store the address and nullifier for the Note
            mapSproutNoteData[nd.first] = nd.second;
        } else {
            // If FindMySproutNotes() was used to obtain noteData,
            // this should never happen
            throw std::logic_error("CWalletTx::SetSproutNoteData(): Invalid note");
        }
    }
}

void CWalletTx::SetSaplingNoteData(mapSaplingNoteData_t &noteData)
{
    mapSaplingNoteData.clear();
    for (const std::pair<SaplingOutPoint, SaplingNoteData> nd : noteData) {
        if (nd.first.n < vShieldedOutput.size()) {
            mapSaplingNoteData[nd.first] = nd.second;
        } else {
            throw std::logic_error("CWalletTx::SetSaplingNoteData(): Invalid note");
        }
    }
}

int64_t CWalletTx::GetTxTime() const
{
    int64_t n = nTimeSmart;
    return n ? n : nTimeReceived;
}

int CWalletTx::GetRequestCount() const
{
    // Returns -1 if it wasn't being tracked
    int nRequests = -1;
    {
        LOCK(pwallet->cs_wallet);
        if (IsCoinBase())
        {
            // Generated block
            if (!hashBlock.IsNull())
            {
                map<uint256, int>::const_iterator mi = pwallet->mapRequestCount.find(hashBlock);
                if (mi != pwallet->mapRequestCount.end())
                    nRequests = (*mi).second;
            }
        }
        else
        {
            // Did anyone request this transaction?
            map<uint256, int>::const_iterator mi = pwallet->mapRequestCount.find(GetHash());
            if (mi != pwallet->mapRequestCount.end())
            {
                nRequests = (*mi).second;

                // How about the block it's in?
                if (nRequests == 0 && !hashBlock.IsNull())
                {
                    map<uint256, int>::const_iterator mi = pwallet->mapRequestCount.find(hashBlock);
                    if (mi != pwallet->mapRequestCount.end())
                        nRequests = (*mi).second;
                    else
                        nRequests = 1; // If it's in someone else's block it must have got out
                }
            }
        }
    }
    return nRequests;
}

// GetAmounts will determine the transparent debits and credits for a given wallet tx.
void CWalletTx::GetAmounts(list<COutputEntry>& listReceived,
                           list<COutputEntry>& listSent, CAmount& nFee, string& strSentAccount, const isminefilter& filter) const
{
    nFee = 0;
    listReceived.clear();
    listSent.clear();
    strSentAccount = strFromAccount;

    // Is this tx sent/signed by me?
    CAmount nDebit = GetDebit(filter);
    bool isFromMyTaddr = nDebit > 0; // debit>0 means we signed/sent this transaction

    // Does this tx spend my notes?
    bool isFromMyZaddr = false;
    for (const JSDescription& js : vjoinsplit) {
        for (const uint256& nullifier : js.nullifiers) {
            if (pwallet->IsSproutNullifierFromMe(nullifier)) {
                isFromMyZaddr = true;
                break;
            }
        }
        if (isFromMyZaddr) {
            break;
        }
    }

    // Compute fee if we sent this transaction.
    if (isFromMyTaddr) {
        CAmount nValueOut = GetValueOut();  // transparent outputs plus all vpub_old
        CAmount nValueIn = 0;
        nValueIn += GetShieldedValueIn();
        nFee = nDebit - nValueOut + nValueIn;
    }

    // Create output entry for vpub_old/new, if we sent utxos from this transaction
    if (isFromMyTaddr) {
        CAmount myVpubOld = 0;
        CAmount myVpubNew = 0;
        for (const JSDescription& js : vjoinsplit) {
            bool fMyJSDesc = false;

            // Check input side
            for (const uint256& nullifier : js.nullifiers) {
                if (pwallet->IsSproutNullifierFromMe(nullifier)) {
                    fMyJSDesc = true;
                    break;
                }
            }

            // Check output side
            if (!fMyJSDesc) {
                for (const std::pair<JSOutPoint, SproutNoteData> nd : this->mapSproutNoteData) {
                    if (nd.first.js < vjoinsplit.size() && nd.first.n < vjoinsplit[nd.first.js].ciphertexts.size()) {
                        fMyJSDesc = true;
                        break;
                    }
                }
            }

            if (fMyJSDesc) {
                myVpubOld += js.vpub_old;
                myVpubNew += js.vpub_new;
            }

            if (!MoneyRange(js.vpub_old) || !MoneyRange(js.vpub_new) || !MoneyRange(myVpubOld) || !MoneyRange(myVpubNew)) {
                 throw std::runtime_error("CWalletTx::GetAmounts: value out of range");
            }
        }

        // Create an output for the value taken from or added to the transparent value pool by JoinSplits
        if (myVpubOld > myVpubNew) {
            COutputEntry output = {CNoDestination(), myVpubOld - myVpubNew, (int)vout.size()};
            listSent.push_back(output);
        } else if (myVpubNew > myVpubOld) {
            COutputEntry output = {CNoDestination(), myVpubNew - myVpubOld, (int)vout.size()};
            listReceived.push_back(output);
        }
    }

    // Sent/received.
    for (unsigned int i = 0; i < vout.size(); ++i)
    {
        const CTxOut& txout = vout[i];
        isminetype fIsMine = pwallet->IsMine(txout);
        // Only need to handle txouts if AT LEAST one of these is true:
        //   1) they debit from us (sent)
        //   2) the output is to us (received)
        if (nDebit > 0)
        {
            // Don't report 'change' txouts
            if (pwallet->IsChange(txout))
                continue;
        }
        else if (!(fIsMine & filter))
            continue;

        // In either case, we need to get the destination address
        CTxDestination address;
        if (!ExtractDestination(txout.scriptPubKey, address))
        {
            LogPrintf("CWalletTx::GetAmounts: Unknown transaction type found, txid %s\n",
                     this->GetHash().ToString());
            address = CNoDestination();
        }

        COutputEntry output = {address, txout.nValue, (int)i};

        // If we are debited by the transaction, add the output as a "sent" entry
        if (nDebit > 0)
            listSent.push_back(output);

        // If we are receiving the output, add it as a "received" entry
        if (fIsMine & filter)
            listReceived.push_back(output);
    }

}

void CWalletTx::GetAccountAmounts(const string& strAccount, CAmount& nReceived,
                                  CAmount& nSent, CAmount& nFee, const isminefilter& filter) const
{
    nReceived = nSent = nFee = 0;

    CAmount allFee;
    string strSentAccount;
    list<COutputEntry> listReceived;
    list<COutputEntry> listSent;
    GetAmounts(listReceived, listSent, allFee, strSentAccount, filter);

    if (strAccount == strSentAccount)
    {
        BOOST_FOREACH(const COutputEntry& s, listSent)
            nSent += s.amount;
        nFee = allFee;
    }
    {
        LOCK(pwallet->cs_wallet);
        BOOST_FOREACH(const COutputEntry& r, listReceived)
        {
            if (pwallet->mapAddressBook.count(r.destination))
            {
                map<CTxDestination, CAddressBookData>::const_iterator mi = pwallet->mapAddressBook.find(r.destination);
                if (mi != pwallet->mapAddressBook.end() && (*mi).second.name == strAccount)
                    nReceived += r.amount;
            }
            else if (strAccount.empty())
            {
                nReceived += r.amount;
            }
        }
    }
}


bool CWalletTx::WriteToDisk(CWalletDB *pwalletdb)
{
    return pwalletdb->WriteTx(GetHash(), *this);
}

void CWallet::WitnessNoteCommitment(std::vector<uint256> commitments,
                                    std::vector<boost::optional<SproutWitness>>& witnesses,
                                    uint256 &final_anchor)
{
    witnesses.resize(commitments.size());
    CBlockIndex* pindex = chainActive.Genesis();
    SproutMerkleTree tree;

    while (pindex) {
        CBlock block;
        ReadBlockFromDisk(block, pindex);

        BOOST_FOREACH(const CTransaction& tx, block.vtx)
        {
            BOOST_FOREACH(const JSDescription& jsdesc, tx.vjoinsplit)
            {
                BOOST_FOREACH(const uint256 &note_commitment, jsdesc.commitments)
                {
                    tree.append(note_commitment);

                    BOOST_FOREACH(boost::optional<SproutWitness>& wit, witnesses) {
                        if (wit) {
                            wit->append(note_commitment);
                        }
                    }

                    size_t i = 0;
                    BOOST_FOREACH(uint256& commitment, commitments) {
                        if (note_commitment == commitment) {
                            witnesses.at(i) = tree.witness();
                        }
                        i++;
                    }
                }
            }
        }

        uint256 current_anchor = tree.root();

        // Consistency check: we should be able to find the current tree
        // in our CCoins view.
        SproutMerkleTree dummy_tree;
        assert(pcoinsTip->GetSproutAnchorAt(current_anchor, dummy_tree));

        pindex = chainActive.Next(pindex);
    }

    // TODO: #93; Select a root via some heuristic.
    final_anchor = tree.root();

    BOOST_FOREACH(boost::optional<SproutWitness>& wit, witnesses) {
        if (wit) {
            assert(final_anchor == wit->root());
        }
    }
}

/**
 * Scan the block chain (starting in pindexStart) for transactions
 * from or to us. If fUpdate is true, found transactions that already
 * exist in the wallet will be updated.
 */
int CWallet::ScanForWalletTransactions(CBlockIndex* pindexStart, bool fUpdate)
{
    int ret = 0;
    int64_t nNow = GetTime();
    const CChainParams& chainParams = Params();

    CBlockIndex* pindex = pindexStart;
    {
        LOCK2(cs_main, cs_wallet);

        // no need to read and scan block, if block was created before
        // our wallet birthday (as adjusted for block time variability)
        while (pindex && nTimeFirstKey && (pindex->GetBlockTime() < (nTimeFirstKey - 7200)))
            pindex = chainActive.Next(pindex);

        ShowProgress(_("Rescanning..."), 0); // show rescan progress in GUI as dialog or on splashscreen, if -rescan on startup
        double dProgressStart = Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), pindex, false);
        double dProgressTip = Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), chainActive.Tip(), false);
        while (pindex)
        {
            if (pindex->nHeight % 100 == 0 && dProgressTip - dProgressStart > 0.0)
                ShowProgress(_("Rescanning..."), std::max(1, std::min(99, (int)((Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), pindex, false) - dProgressStart) / (dProgressTip - dProgressStart) * 100))));

            CBlock block;
            ReadBlockFromDisk(block, pindex);
            BOOST_FOREACH(CTransaction& tx, block.vtx)
            {
                if (AddToWalletIfInvolvingMe(tx, &block, fUpdate))
                    ret++;
            }

            SproutMerkleTree sproutTree;
            SaplingMerkleTree saplingTree;
            // This should never fail: we should always be able to get the tree
            // state on the path to the tip of our chain
            assert(pcoinsTip->GetSproutAnchorAt(pindex->hashSproutAnchor, sproutTree));
            if (pindex->pprev) {
                if (NetworkUpgradeActive(pindex->pprev->nHeight, Params().GetConsensus(), Consensus::UPGRADE_SAPLING)) {
                    assert(pcoinsTip->GetSaplingAnchorAt(pindex->pprev->hashFinalSaplingRoot, saplingTree));
                }
            }
            // Increment note witness caches
            IncrementNoteWitnesses(pindex, &block, sproutTree, saplingTree);

            pindex = chainActive.Next(pindex);
            if (GetTime() >= nNow + 60) {
                nNow = GetTime();
                LogPrintf("Still rescanning. At block %d. Progress=%f\n", pindex->nHeight, Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), pindex));
            }
        }
        ShowProgress(_("Rescanning..."), 100); // hide progress dialog in GUI
    }
    return ret;
}

void CWallet::ReacceptWalletTransactions()
{
    // If transactions aren't being broadcasted, don't let them into local mempool either
    if (!fBroadcastTransactions)
        return;
    LOCK2(cs_main, cs_wallet);
    std::map<int64_t, CWalletTx*> mapSorted;

    // Sort pending wallet transactions based on their initial wallet insertion order
    BOOST_FOREACH(PAIRTYPE(const uint256, CWalletTx)& item, mapWallet)
    {
        const uint256& wtxid = item.first;
        CWalletTx& wtx = item.second;
        assert(wtx.GetHash() == wtxid);

        int nDepth = wtx.GetDepthInMainChain();

        if (!wtx.IsCoinBase() && nDepth < 0) {
            mapSorted.insert(std::make_pair(wtx.nOrderPos, &wtx));
        }
    }

    // Try to add wallet transactions to memory pool
    BOOST_FOREACH(PAIRTYPE(const int64_t, CWalletTx*)& item, mapSorted)
    {
        CWalletTx& wtx = *(item.second);

        LOCK(mempool.cs);
        wtx.AcceptToMemoryPool(false);
    }
}

bool CWalletTx::RelayWalletTransaction()
{
    assert(pwallet->GetBroadcastTransactions());
    if (!IsCoinBase())
    {
        if (GetDepthInMainChain() == 0) {
            LogPrintf("Relaying wtx %s\n", GetHash().ToString());
            RelayTransaction((CTransaction)*this);
            return true;
        }
    }
    return false;
}

set<uint256> CWalletTx::GetConflicts() const
{
    set<uint256> result;
    if (pwallet != NULL)
    {
        uint256 myHash = GetHash();
        result = pwallet->GetConflicts(myHash);
        result.erase(myHash);
    }
    return result;
}

CAmount CWalletTx::GetDebit(const isminefilter& filter) const
{
    if (vin.empty())
        return 0;

    CAmount debit = 0;
    if(filter & ISMINE_SPENDABLE)
    {
        if (fDebitCached)
            debit += nDebitCached;
        else
        {
            nDebitCached = pwallet->GetDebit(*this, ISMINE_SPENDABLE);
            fDebitCached = true;
            debit += nDebitCached;
        }
    }
    if(filter & ISMINE_WATCH_ONLY)
    {
        if(fWatchDebitCached)
            debit += nWatchDebitCached;
        else
        {
            nWatchDebitCached = pwallet->GetDebit(*this, ISMINE_WATCH_ONLY);
            fWatchDebitCached = true;
            debit += nWatchDebitCached;
        }
    }
    return debit;
}

CAmount CWalletTx::GetCredit(const isminefilter& filter) const
{
    // Must wait until coinbase is safely deep enough in the chain before valuing it
    if (IsCoinBase() && GetBlocksToMaturity() > 0)
        return 0;

    int64_t credit = 0;
    if (filter & ISMINE_SPENDABLE)
    {
        // GetBalance can assume transactions in mapWallet won't change
        if (fCreditCached)
            credit += nCreditCached;
        else
        {
            nCreditCached = pwallet->GetCredit(*this, ISMINE_SPENDABLE);
            fCreditCached = true;
            credit += nCreditCached;
        }
    }
    if (filter & ISMINE_WATCH_ONLY)
    {
        if (fWatchCreditCached)
            credit += nWatchCreditCached;
        else
        {
            nWatchCreditCached = pwallet->GetCredit(*this, ISMINE_WATCH_ONLY);
            fWatchCreditCached = true;
            credit += nWatchCreditCached;
        }
    }
    return credit;
}

CAmount CWalletTx::GetImmatureCredit(bool fUseCache) const
{
    if (IsCoinBase() && GetBlocksToMaturity() > 0 && IsInMainChain())
    {
        if (fUseCache && fImmatureCreditCached)
            return nImmatureCreditCached;
        nImmatureCreditCached = pwallet->GetCredit(*this, ISMINE_SPENDABLE);
        fImmatureCreditCached = true;
        return nImmatureCreditCached;
    }

    return 0;
}

CAmount CWalletTx::GetAvailableCredit(bool fUseCache) const
{
    if (pwallet == 0)
        return 0;

    // Must wait until coinbase is safely deep enough in the chain before valuing it
    if (IsCoinBase() && GetBlocksToMaturity() > 0)
        return 0;

    if (fUseCache && fAvailableCreditCached)
        return nAvailableCreditCached;

    CAmount nCredit = 0;
    uint256 hashTx = GetHash();
    for (unsigned int i = 0; i < vout.size(); i++)
    {
        if (!pwallet->IsSpent(hashTx, i))
        {
            const CTxOut &txout = vout[i];
            nCredit += pwallet->GetCredit(txout, ISMINE_SPENDABLE);
            if (!MoneyRange(nCredit))
                throw std::runtime_error("CWalletTx::GetAvailableCredit() : value out of range");
        }
    }

    nAvailableCreditCached = nCredit;
    fAvailableCreditCached = true;
    return nCredit;
}

CAmount CWalletTx::GetImmatureWatchOnlyCredit(const bool& fUseCache) const
{
    if (IsCoinBase() && GetBlocksToMaturity() > 0 && IsInMainChain())
    {
        if (fUseCache && fImmatureWatchCreditCached)
            return nImmatureWatchCreditCached;
        nImmatureWatchCreditCached = pwallet->GetCredit(*this, ISMINE_WATCH_ONLY);
        fImmatureWatchCreditCached = true;
        return nImmatureWatchCreditCached;
    }

    return 0;
}

CAmount CWalletTx::GetAvailableWatchOnlyCredit(const bool& fUseCache) const
{
    if (pwallet == 0)
        return 0;

    // Must wait until coinbase is safely deep enough in the chain before valuing it
    if (IsCoinBase() && GetBlocksToMaturity() > 0)
        return 0;

    if (fUseCache && fAvailableWatchCreditCached)
        return nAvailableWatchCreditCached;

    CAmount nCredit = 0;
    for (unsigned int i = 0; i < vout.size(); i++)
    {
        if (!pwallet->IsSpent(GetHash(), i))
        {
            const CTxOut &txout = vout[i];
            nCredit += pwallet->GetCredit(txout, ISMINE_WATCH_ONLY);
            if (!MoneyRange(nCredit))
                throw std::runtime_error("CWalletTx::GetAvailableCredit() : value out of range");
        }
    }

    nAvailableWatchCreditCached = nCredit;
    fAvailableWatchCreditCached = true;
    return nCredit;
}

CAmount CWalletTx::GetChange() const
{
    if (fChangeCached)
        return nChangeCached;
    nChangeCached = pwallet->GetChange(*this);
    fChangeCached = true;
    return nChangeCached;
}

bool CWalletTx::IsTrusted() const
{
    // Quick answer in most cases
    if (!CheckFinalTx(*this))
        return false;
    int nDepth = GetDepthInMainChain();
    if (nDepth >= 1)
        return true;
    if (nDepth < 0)
        return false;
    if (!bSpendZeroConfChange || !IsFromMe(ISMINE_ALL)) // using wtx's cached debit
        return false;

    // Trusted if all inputs are from us and are in the mempool:
    BOOST_FOREACH(const CTxIn& txin, vin)
    {
        // Transactions not sent by us: not trusted
        const CWalletTx* parent = pwallet->GetWalletTx(txin.prevout.hash);
        if (parent == NULL)
            return false;
        const CTxOut& parentOut = parent->vout[txin.prevout.n];
        if (pwallet->IsMine(parentOut) != ISMINE_SPENDABLE)
            return false;
    }
    return true;
}

std::vector<uint256> CWallet::ResendWalletTransactionsBefore(int64_t nTime)
{
    std::vector<uint256> result;

    LOCK(cs_wallet);
    // Sort them in chronological order
    multimap<unsigned int, CWalletTx*> mapSorted;
    BOOST_FOREACH(PAIRTYPE(const uint256, CWalletTx)& item, mapWallet)
    {
        CWalletTx& wtx = item.second;
        // Don't rebroadcast if newer than nTime:
        if (wtx.nTimeReceived > nTime)
            continue;
        mapSorted.insert(make_pair(wtx.nTimeReceived, &wtx));
    }
    BOOST_FOREACH(PAIRTYPE(const unsigned int, CWalletTx*)& item, mapSorted)
    {
        CWalletTx& wtx = *item.second;
        if (wtx.RelayWalletTransaction())
            result.push_back(wtx.GetHash());
    }
    return result;
}

void CWallet::ResendWalletTransactions(int64_t nBestBlockTime)
{
    // Do this infrequently and randomly to avoid giving away
    // that these are our transactions.
    if (GetTime() < nNextResend || !fBroadcastTransactions)
        return;
    bool fFirst = (nNextResend == 0);
    nNextResend = GetTime() + GetRand(30 * 60);
    if (fFirst)
        return;

    // Only do it if there's been a new block since last time
    if (nBestBlockTime < nLastResend)
        return;
    nLastResend = GetTime();

    // Rebroadcast unconfirmed txes older than 5 minutes before the last
    // block was found:
    std::vector<uint256> relayed = ResendWalletTransactionsBefore(nBestBlockTime-5*60);
    if (!relayed.empty())
        LogPrintf("%s: rebroadcast %u unconfirmed transactions\n", __func__, relayed.size());
}

/** @} */ // end of mapWallet




/** @defgroup Actions
 *
 * @{
 */


CAmount CWallet::GetBalance() const
{
    CAmount nTotal = 0;
    {
        LOCK2(cs_main, cs_wallet);
        for (map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
        {
            const CWalletTx* pcoin = &(*it).second;
            if (pcoin->IsTrusted())
                nTotal += pcoin->GetAvailableCredit();
        }
    }

    return nTotal;
}

CAmount CWallet::GetUnconfirmedBalance() const
{
    CAmount nTotal = 0;
    {
        LOCK2(cs_main, cs_wallet);
        for (map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
        {
            const CWalletTx* pcoin = &(*it).second;
            if (!CheckFinalTx(*pcoin) || (!pcoin->IsTrusted() && pcoin->GetDepthInMainChain() == 0))
                nTotal += pcoin->GetAvailableCredit();
        }
    }
    return nTotal;
}

CAmount CWallet::GetImmatureBalance() const
{
    CAmount nTotal = 0;
    {
        LOCK2(cs_main, cs_wallet);
        for (map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
        {
            const CWalletTx* pcoin = &(*it).second;
            nTotal += pcoin->GetImmatureCredit();
        }
    }
    return nTotal;
}

CAmount CWallet::GetWatchOnlyBalance() const
{
    CAmount nTotal = 0;
    {
        LOCK2(cs_main, cs_wallet);
        for (map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
        {
            const CWalletTx* pcoin = &(*it).second;
            if (pcoin->IsTrusted())
                nTotal += pcoin->GetAvailableWatchOnlyCredit();
        }
    }

    return nTotal;
}

CAmount CWallet::GetUnconfirmedWatchOnlyBalance() const
{
    CAmount nTotal = 0;
    {
        LOCK2(cs_main, cs_wallet);
        for (map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
        {
            const CWalletTx* pcoin = &(*it).second;
            if (!CheckFinalTx(*pcoin) || (!pcoin->IsTrusted() && pcoin->GetDepthInMainChain() == 0))
                nTotal += pcoin->GetAvailableWatchOnlyCredit();
        }
    }
    return nTotal;
}

CAmount CWallet::GetImmatureWatchOnlyBalance() const
{
    CAmount nTotal = 0;
    {
        LOCK2(cs_main, cs_wallet);
        for (map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
        {
            const CWalletTx* pcoin = &(*it).second;
            nTotal += pcoin->GetImmatureWatchOnlyCredit();
        }
    }
    return nTotal;
}

/**
 * populate vCoins with vector of available COutputs.
 */
void CWallet::AvailableCoins(vector<COutput>& vCoins, bool fOnlyConfirmed, const CCoinControl *coinControl, bool fIncludeZeroValue, bool fIncludeCoinBase) const
{
    vCoins.clear();

    {
        LOCK2(cs_main, cs_wallet);
        for (map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
        {
            const uint256& wtxid = it->first;
            const CWalletTx* pcoin = &(*it).second;

            if (!CheckFinalTx(*pcoin))
                continue;

            if (fOnlyConfirmed && !pcoin->IsTrusted())
                continue;

            if (pcoin->IsCoinBase() && !fIncludeCoinBase)
                continue;

            if (pcoin->IsCoinBase() && pcoin->GetBlocksToMaturity() > 0)
                continue;

            int nDepth = pcoin->GetDepthInMainChain();
            if (nDepth < 0)
                continue;

            for (unsigned int i = 0; i < pcoin->vout.size(); i++) {
                isminetype mine = IsMine(pcoin->vout[i]);
                if (!(IsSpent(wtxid, i)) && mine != ISMINE_NO &&
                    !IsLockedCoin((*it).first, i) && (pcoin->vout[i].nValue > 0 || fIncludeZeroValue) &&
                    (!coinControl || !coinControl->HasSelected() || coinControl->fAllowOtherInputs || coinControl->IsSelected((*it).first, i)))
                        vCoins.push_back(COutput(pcoin, i, nDepth, (mine & ISMINE_SPENDABLE) != ISMINE_NO));
            }
        }
    }
}

static void ApproximateBestSubset(vector<pair<CAmount, pair<const CWalletTx*,unsigned int> > >vValue, const CAmount& nTotalLower, const CAmount& nTargetValue,
                                  vector<char>& vfBest, CAmount& nBest, int iterations = 1000)
{
    vector<char> vfIncluded;

    vfBest.assign(vValue.size(), true);
    nBest = nTotalLower;

    seed_insecure_rand();

    for (int nRep = 0; nRep < iterations && nBest != nTargetValue; nRep++)
    {
        vfIncluded.assign(vValue.size(), false);
        CAmount nTotal = 0;
        bool fReachedTarget = false;
        for (int nPass = 0; nPass < 2 && !fReachedTarget; nPass++)
        {
            for (unsigned int i = 0; i < vValue.size(); i++)
            {
                //The solver here uses a randomized algorithm,
                //the randomness serves no real security purpose but is just
                //needed to prevent degenerate behavior and it is important
                //that the rng is fast. We do not use a constant random sequence,
                //because there may be some privacy improvement by making
                //the selection random.
                if (nPass == 0 ? insecure_rand()&1 : !vfIncluded[i])
                {
                    nTotal += vValue[i].first;
                    vfIncluded[i] = true;
                    if (nTotal >= nTargetValue)
                    {
                        fReachedTarget = true;
                        if (nTotal < nBest)
                        {
                            nBest = nTotal;
                            vfBest = vfIncluded;
                        }
                        nTotal -= vValue[i].first;
                        vfIncluded[i] = false;
                    }
                }
            }
        }
    }
}

bool CWallet::SelectCoinsMinConf(const CAmount& nTargetValue, int nConfMine, int nConfTheirs, vector<COutput> vCoins,
                                 set<pair<const CWalletTx*,unsigned int> >& setCoinsRet, CAmount& nValueRet) const
{
    setCoinsRet.clear();
    nValueRet = 0;

    // List of values less than target
    pair<CAmount, pair<const CWalletTx*,unsigned int> > coinLowestLarger;
    coinLowestLarger.first = std::numeric_limits<CAmount>::max();
    coinLowestLarger.second.first = NULL;
    vector<pair<CAmount, pair<const CWalletTx*,unsigned int> > > vValue;
    CAmount nTotalLower = 0;

    random_shuffle(vCoins.begin(), vCoins.end(), GetRandInt);

    BOOST_FOREACH(const COutput &output, vCoins)
    {
        if (!output.fSpendable)
            continue;

        const CWalletTx *pcoin = output.tx;

        if (output.nDepth < (pcoin->IsFromMe(ISMINE_ALL) ? nConfMine : nConfTheirs))
            continue;

        int i = output.i;
        CAmount n = pcoin->vout[i].nValue;

        pair<CAmount,pair<const CWalletTx*,unsigned int> > coin = make_pair(n,make_pair(pcoin, i));

        if (n == nTargetValue)
        {
            setCoinsRet.insert(coin.second);
            nValueRet += coin.first;
            return true;
        }
        else if (n < nTargetValue + CENT)
        {
            vValue.push_back(coin);
            nTotalLower += n;
        }
        else if (n < coinLowestLarger.first)
        {
            coinLowestLarger = coin;
        }
    }

    if (nTotalLower == nTargetValue)
    {
        for (unsigned int i = 0; i < vValue.size(); ++i)
        {
            setCoinsRet.insert(vValue[i].second);
            nValueRet += vValue[i].first;
        }
        return true;
    }

    if (nTotalLower < nTargetValue)
    {
        if (coinLowestLarger.second.first == NULL)
            return false;
        setCoinsRet.insert(coinLowestLarger.second);
        nValueRet += coinLowestLarger.first;
        return true;
    }

    // Solve subset sum by stochastic approximation
    sort(vValue.rbegin(), vValue.rend(), CompareValueOnly());
    vector<char> vfBest;
    CAmount nBest;

    ApproximateBestSubset(vValue, nTotalLower, nTargetValue, vfBest, nBest, 1000);
    if (nBest != nTargetValue && nTotalLower >= nTargetValue + CENT)
        ApproximateBestSubset(vValue, nTotalLower, nTargetValue + CENT, vfBest, nBest, 1000);

    // If we have a bigger coin and (either the stochastic approximation didn't find a good solution,
    //                                   or the next bigger coin is closer), return the bigger coin
    if (coinLowestLarger.second.first &&
        ((nBest != nTargetValue && nBest < nTargetValue + CENT) || coinLowestLarger.first <= nBest))
    {
        setCoinsRet.insert(coinLowestLarger.second);
        nValueRet += coinLowestLarger.first;
    }
    else {
        for (unsigned int i = 0; i < vValue.size(); i++)
            if (vfBest[i])
            {
                setCoinsRet.insert(vValue[i].second);
                nValueRet += vValue[i].first;
            }

        LogPrint("selectcoins", "SelectCoins() best subset: ");
        for (unsigned int i = 0; i < vValue.size(); i++)
            if (vfBest[i])
                LogPrint("selectcoins", "%s ", FormatMoney(vValue[i].first));
        LogPrint("selectcoins", "total %s\n", FormatMoney(nBest));
    }

    return true;
}

bool CWallet::SelectCoins(const CAmount& nTargetValue, set<pair<const CWalletTx*,unsigned int> >& setCoinsRet, CAmount& nValueRet,  bool& fOnlyCoinbaseCoinsRet, bool& fNeedCoinbaseCoinsRet, const CCoinControl* coinControl) const
{
    // Output parameter fOnlyCoinbaseCoinsRet is set to true when the only available coins are coinbase utxos.
    vector<COutput> vCoinsNoCoinbase, vCoinsWithCoinbase;
    AvailableCoins(vCoinsNoCoinbase, true, coinControl, false, false);
    AvailableCoins(vCoinsWithCoinbase, true, coinControl, false, true);
    fOnlyCoinbaseCoinsRet = vCoinsNoCoinbase.size() == 0 && vCoinsWithCoinbase.size() > 0;

    // If coinbase utxos can only be sent to zaddrs, exclude any coinbase utxos from coin selection.
    bool fProtectCoinbase = Params().GetConsensus().fCoinbaseMustBeProtected;
    vector<COutput> vCoins = (fProtectCoinbase) ? vCoinsNoCoinbase : vCoinsWithCoinbase;

    // Output parameter fNeedCoinbaseCoinsRet is set to true if coinbase utxos need to be spent to meet target amount
    if (fProtectCoinbase && vCoinsWithCoinbase.size() > vCoinsNoCoinbase.size()) {
        CAmount value = 0;
        for (const COutput& out : vCoinsNoCoinbase) {
            if (!out.fSpendable) {
                continue;
            }
            value += out.tx->vout[out.i].nValue;
        }
        if (value <= nTargetValue) {
            CAmount valueWithCoinbase = 0;
            for (const COutput& out : vCoinsWithCoinbase) {
                if (!out.fSpendable) {
                    continue;
                }
                valueWithCoinbase += out.tx->vout[out.i].nValue;
            }
            fNeedCoinbaseCoinsRet = (valueWithCoinbase >= nTargetValue);
        }
    }

    // coin control -> return all selected outputs (we want all selected to go into the transaction for sure)
    if (coinControl && coinControl->HasSelected() && !coinControl->fAllowOtherInputs)
    {
        BOOST_FOREACH(const COutput& out, vCoins)
        {
            if (!out.fSpendable)
                 continue;
            nValueRet += out.tx->vout[out.i].nValue;
            setCoinsRet.insert(make_pair(out.tx, out.i));
        }
        return (nValueRet >= nTargetValue);
    }

    // calculate value from preset inputs and store them
    set<pair<const CWalletTx*, uint32_t> > setPresetCoins;
    CAmount nValueFromPresetInputs = 0;

    std::vector<COutPoint> vPresetInputs;
    if (coinControl)
        coinControl->ListSelected(vPresetInputs);
    BOOST_FOREACH(const COutPoint& outpoint, vPresetInputs)
    {
        map<uint256, CWalletTx>::const_iterator it = mapWallet.find(outpoint.hash);
        if (it != mapWallet.end())
        {
            const CWalletTx* pcoin = &it->second;
            // Clearly invalid input, fail
            if (pcoin->vout.size() <= outpoint.n)
                return false;
            nValueFromPresetInputs += pcoin->vout[outpoint.n].nValue;
            setPresetCoins.insert(make_pair(pcoin, outpoint.n));
        } else
            return false; // TODO: Allow non-wallet inputs
    }

    // remove preset inputs from vCoins
    for (vector<COutput>::iterator it = vCoins.begin(); it != vCoins.end() && coinControl && coinControl->HasSelected();)
    {
        if (setPresetCoins.count(make_pair(it->tx, it->i)))
            it = vCoins.erase(it);
        else
            ++it;
    }

    bool res = nTargetValue <= nValueFromPresetInputs ||
        SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 1, 6, vCoins, setCoinsRet, nValueRet) ||
        SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 1, 1, vCoins, setCoinsRet, nValueRet) ||
        (bSpendZeroConfChange && SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 0, 1, vCoins, setCoinsRet, nValueRet));

    // because SelectCoinsMinConf clears the setCoinsRet, we now add the possible inputs to the coinset
    setCoinsRet.insert(setPresetCoins.begin(), setPresetCoins.end());

    // add preset inputs to the total value selected
    nValueRet += nValueFromPresetInputs;

    return res;
}

bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount &nFeeRet, int& nChangePosRet, std::string& strFailReason)
{
    vector<CRecipient> vecSend;

    // Turn the txout set into a CRecipient vector
    BOOST_FOREACH(const CTxOut& txOut, tx.vout)
    {
        CRecipient recipient = {txOut.scriptPubKey, txOut.nValue, false};
        vecSend.push_back(recipient);
    }

    CCoinControl coinControl;
    coinControl.fAllowOtherInputs = true;
    BOOST_FOREACH(const CTxIn& txin, tx.vin)
        coinControl.Select(txin.prevout);

    CReserveKey reservekey(this);
    CWalletTx wtx;

    if (!CreateTransaction(vecSend, wtx, reservekey, nFeeRet, nChangePosRet, strFailReason, &coinControl, false))
        return false;

    if (nChangePosRet != -1)
        tx.vout.insert(tx.vout.begin() + nChangePosRet, wtx.vout[nChangePosRet]);

    // Add new txins (keeping original txin scriptSig/order)
    BOOST_FOREACH(const CTxIn& txin, wtx.vin)
    {
        bool found = false;
        BOOST_FOREACH(const CTxIn& origTxIn, tx.vin)
        {
            if (txin.prevout.hash == origTxIn.prevout.hash && txin.prevout.n == origTxIn.prevout.n)
            {
                found = true;
                break;
            }
        }
        if (!found)
            tx.vin.push_back(txin);
    }

    return true;
}

bool CWallet::CreateTransaction(const vector<CRecipient>& vecSend, CWalletTx& wtxNew, CReserveKey& reservekey, CAmount& nFeeRet,
                                int& nChangePosRet, std::string& strFailReason, const CCoinControl* coinControl, bool sign)
{
    CAmount nValue = 0;
    unsigned int nSubtractFeeFromAmount = 0;
    BOOST_FOREACH (const CRecipient& recipient, vecSend)
    {
        if (nValue < 0 || recipient.nAmount < 0)
        {
            strFailReason = _("Transaction amounts must be positive");
            return false;
        }
        nValue += recipient.nAmount;

        if (recipient.fSubtractFeeFromAmount)
            nSubtractFeeFromAmount++;
    }
    if (vecSend.empty() || nValue < 0)
    {
        strFailReason = _("Transaction amounts must be positive");
        return false;
    }

    wtxNew.fTimeReceivedIsTxTime = true;
    wtxNew.BindWallet(this);
    int nextBlockHeight = chainActive.Height() + 1;
    CMutableTransaction txNew = CreateNewContextualCMutableTransaction(
        Params().GetConsensus(), nextBlockHeight);

    // Activates after Overwinter network upgrade
    if (NetworkUpgradeActive(nextBlockHeight, Params().GetConsensus(), Consensus::UPGRADE_OVERWINTER)) {
        if (txNew.nExpiryHeight >= TX_EXPIRY_HEIGHT_THRESHOLD){
            strFailReason = _("nExpiryHeight must be less than TX_EXPIRY_HEIGHT_THRESHOLD.");
            return false;
        }
    }

    unsigned int max_tx_size = MAX_TX_SIZE_AFTER_SAPLING;
    if (!NetworkUpgradeActive(nextBlockHeight, Params().GetConsensus(), Consensus::UPGRADE_SAPLING)) {
        max_tx_size = MAX_TX_SIZE_BEFORE_SAPLING;
    }

    // Discourage fee sniping.
    //
    // However because of a off-by-one-error in previous versions we need to
    // neuter it by setting nLockTime to at least one less than nBestHeight.
    // Secondly currently propagation of transactions created for block heights
    // corresponding to blocks that were just mined may be iffy - transactions
    // aren't re-accepted into the mempool - we additionally neuter the code by
    // going ten blocks back. Doesn't yet do anything for sniping, but does act
    // to shake out wallet bugs like not showing nLockTime'd transactions at
    // all.
    txNew.nLockTime = std::max(0, chainActive.Height() - 10);

    // Secondly occasionally randomly pick a nLockTime even further back, so
    // that transactions that are delayed after signing for whatever reason,
    // e.g. high-latency mix networks and some CoinJoin implementations, have
    // better privacy.
    if (GetRandInt(10) == 0)
        txNew.nLockTime = std::max(0, (int)txNew.nLockTime - GetRandInt(100));

    assert(txNew.nLockTime <= (unsigned int)chainActive.Height());
    assert(txNew.nLockTime < LOCKTIME_THRESHOLD);

    {
        LOCK2(cs_main, cs_wallet);
        {
            nFeeRet = 0;
            while (true)
            {
                txNew.vin.clear();
                txNew.vout.clear();
                wtxNew.fFromMe = true;
                nChangePosRet = -1;
                bool fFirst = true;

                CAmount nTotalValue = nValue;
                if (nSubtractFeeFromAmount == 0)
                    nTotalValue += nFeeRet;
                double dPriority = 0;
                // vouts to the payees
                BOOST_FOREACH (const CRecipient& recipient, vecSend)
                {
                    CTxOut txout(recipient.nAmount, recipient.scriptPubKey);

                    if (recipient.fSubtractFeeFromAmount)
                    {
                        txout.nValue -= nFeeRet / nSubtractFeeFromAmount; // Subtract fee equally from each selected recipient

                        if (fFirst) // first receiver pays the remainder not divisible by output count
                        {
                            fFirst = false;
                            txout.nValue -= nFeeRet % nSubtractFeeFromAmount;
                        }
                    }

                    if (txout.IsDust(::minRelayTxFee))
                    {
                        if (recipient.fSubtractFeeFromAmount && nFeeRet > 0)
                        {
                            if (txout.nValue < 0)
                                strFailReason = _("The transaction amount is too small to pay the fee");
                            else
                                strFailReason = _("The transaction amount is too small to send after the fee has been deducted");
                        }
                        else
                            strFailReason = _("Transaction amount too small");
                        return false;
                    }
                    txNew.vout.push_back(txout);
                }

                // Choose coins to use
                set<pair<const CWalletTx*,unsigned int> > setCoins;
                CAmount nValueIn = 0;
                bool fOnlyCoinbaseCoins = false;
                bool fNeedCoinbaseCoins = false;
                if (!SelectCoins(nTotalValue, setCoins, nValueIn, fOnlyCoinbaseCoins, fNeedCoinbaseCoins, coinControl))
                {
                    if (fOnlyCoinbaseCoins && Params().GetConsensus().fCoinbaseMustBeProtected) {
                        strFailReason = _("Coinbase funds can only be sent to a zaddr");
                    } else if (fNeedCoinbaseCoins) {
                        strFailReason = _("Insufficient funds, coinbase funds can only be spent after they have been sent to a zaddr");
                    } else {
                        strFailReason = _("Insufficient funds");
                    }
                    return false;
                }
                BOOST_FOREACH(PAIRTYPE(const CWalletTx*, unsigned int) pcoin, setCoins)
                {
                    CAmount nCredit = pcoin.first->vout[pcoin.second].nValue;
                    //The coin age after the next block (depth+1) is used instead of the current,
                    //reflecting an assumption the user would accept a bit more delay for
                    //a chance at a free transaction.
                    //But mempool inputs might still be in the mempool, so their age stays 0
                    int age = pcoin.first->GetDepthInMainChain();
                    if (age != 0)
                        age += 1;
                    dPriority += (double)nCredit * age;
                }

                CAmount nChange = nValueIn - nValue;
                if (nSubtractFeeFromAmount == 0)
                    nChange -= nFeeRet;

                if (nChange > 0)
                {
                    // Fill a vout to ourself
                    // TODO: pass in scriptChange instead of reservekey so
                    // change transaction isn't always pay-to-bitcoin-address
                    CScript scriptChange;

                    // coin control: send change to custom address
                    if (coinControl && !boost::get<CNoDestination>(&coinControl->destChange))
                        scriptChange = GetScriptForDestination(coinControl->destChange);

                    // no coin control: send change to newly generated address
                    else
                    {
                        // Note: We use a new key here to keep it from being obvious which side is the change.
                        //  The drawback is that by not reusing a previous key, the change may be lost if a
                        //  backup is restored, if the backup doesn't have the new private key for the change.
                        //  If we reused the old key, it would be possible to add code to look for and
                        //  rediscover unknown transactions that were written with keys of ours to recover
                        //  post-backup change.

                        // Reserve a new key pair from key pool
                        CPubKey vchPubKey;
                        bool ret;
                        ret = reservekey.GetReservedKey(vchPubKey);
                        assert(ret); // should never fail, as we just unlocked

                        scriptChange = GetScriptForDestination(vchPubKey.GetID());
                    }

                    CTxOut newTxOut(nChange, scriptChange);

                    // We do not move dust-change to fees, because the sender would end up paying more than requested.
                    // This would be against the purpose of the all-inclusive feature.
                    // So instead we raise the change and deduct from the recipient.
                    if (nSubtractFeeFromAmount > 0 && newTxOut.IsDust(::minRelayTxFee))
                    {
                        CAmount nDust = newTxOut.GetDustThreshold(::minRelayTxFee) - newTxOut.nValue;
                        newTxOut.nValue += nDust; // raise change until no more dust
                        for (unsigned int i = 0; i < vecSend.size(); i++) // subtract from first recipient
                        {
                            if (vecSend[i].fSubtractFeeFromAmount)
                            {
                                txNew.vout[i].nValue -= nDust;
                                if (txNew.vout[i].IsDust(::minRelayTxFee))
                                {
                                    strFailReason = _("The transaction amount is too small to send after the fee has been deducted");
                                    return false;
                                }
                                break;
                            }
                        }
                    }

                    // Never create dust outputs; if we would, just
                    // add the dust to the fee.
                    if (newTxOut.IsDust(::minRelayTxFee))
                    {
                        nFeeRet += nChange;
                        reservekey.ReturnKey();
                    }
                    else
                    {
                        // Insert change txn at random position:
                        nChangePosRet = GetRandInt(txNew.vout.size()+1);
                        vector<CTxOut>::iterator position = txNew.vout.begin()+nChangePosRet;
                        txNew.vout.insert(position, newTxOut);
                    }
                }
                else
                    reservekey.ReturnKey();

                // Fill vin
                //
                // Note how the sequence number is set to max()-1 so that the
                // nLockTime set above actually works.
                BOOST_FOREACH(const PAIRTYPE(const CWalletTx*,unsigned int)& coin, setCoins)
                    txNew.vin.push_back(CTxIn(coin.first->GetHash(),coin.second,CScript(),
                                              std::numeric_limits<unsigned int>::max()-1));

                // Check mempooltxinputlimit to avoid creating a transaction which the local mempool rejects
                size_t limit = (size_t)GetArg("-mempooltxinputlimit", 0);
                {
                    LOCK(cs_main);
                    if (NetworkUpgradeActive(chainActive.Height() + 1, Params().GetConsensus(), Consensus::UPGRADE_OVERWINTER)) {
                        limit = 0;
                    }
                }
                if (limit > 0) {
                    size_t n = txNew.vin.size();
                    if (n > limit) {
                        strFailReason = _(strprintf("Too many transparent inputs %zu > limit %zu", n, limit).c_str());
                        return false;
                    }
                }

                // Grab the current consensus branch ID
                auto consensusBranchId = CurrentEpochBranchId(chainActive.Height() + 1, Params().GetConsensus());

                // Sign
                int nIn = 0;
                CTransaction txNewConst(txNew);
                BOOST_FOREACH(const PAIRTYPE(const CWalletTx*,unsigned int)& coin, setCoins)
                {
                    bool signSuccess;
                    const CScript& scriptPubKey = coin.first->vout[coin.second].scriptPubKey;
                    SignatureData sigdata;
                    if (sign)
                        signSuccess = ProduceSignature(TransactionSignatureCreator(this, &txNewConst, nIn, coin.first->vout[coin.second].nValue, SIGHASH_ALL), scriptPubKey, sigdata, consensusBranchId);
                    else
                        signSuccess = ProduceSignature(DummySignatureCreator(this), scriptPubKey, sigdata, consensusBranchId);

                    if (!signSuccess)
                    {
                        strFailReason = _("Signing transaction failed");
                        return false;
                    } else {
                        UpdateTransaction(txNew, nIn, sigdata);
                    }

                    nIn++;
                }

                unsigned int nBytes = ::GetSerializeSize(txNew, SER_NETWORK, PROTOCOL_VERSION);

                // Remove scriptSigs if we used dummy signatures for fee calculation
                if (!sign) {
                    BOOST_FOREACH (CTxIn& vin, txNew.vin)
                        vin.scriptSig = CScript();
                }

                // Embed the constructed transaction data in wtxNew.
                *static_cast<CTransaction*>(&wtxNew) = CTransaction(txNew);

                // Limit size
                if (nBytes >= max_tx_size)
                {
                    strFailReason = _("Transaction too large");
                    return false;
                }

                dPriority = wtxNew.ComputePriority(dPriority, nBytes);

                // Can we complete this as a free transaction?
                if (fSendFreeTransactions && nBytes <= MAX_FREE_TRANSACTION_CREATE_SIZE)
                {
                    // Not enough fee: enough priority?
                    double dPriorityNeeded = mempool.estimatePriority(nTxConfirmTarget);
                    // Not enough mempool history to estimate: use hard-coded AllowFree.
                    if (dPriorityNeeded <= 0 && AllowFree(dPriority))
                        break;

                    // Small enough, and priority high enough, to send for free
                    if (dPriorityNeeded > 0 && dPriority >= dPriorityNeeded)
                        break;
                }

                CAmount nFeeNeeded = GetMinimumFee(nBytes, nTxConfirmTarget, mempool);

                // If we made it here and we aren't even able to meet the relay fee on the next pass, give up
                // because we must be at the maximum allowed fee.
                if (nFeeNeeded < ::minRelayTxFee.GetFee(nBytes))
                {
                    strFailReason = _("Transaction too large for fee policy");
                    return false;
                }

                if (nFeeRet >= nFeeNeeded)
                    break; // Done, enough fee included.

                // Include more fee and try again.
                nFeeRet = nFeeNeeded;
                continue;
            }
        }
    }

    return true;
}

/**
 * Call after CreateTransaction unless you want to abort
 */
bool CWallet::CommitTransaction(CWalletTx& wtxNew, CReserveKey& reservekey)
{
    {
        LOCK2(cs_main, cs_wallet);
        LogPrintf("CommitTransaction:\n%s", wtxNew.ToString());
        {
            // This is only to keep the database open to defeat the auto-flush for the
            // duration of this scope.  This is the only place where this optimization
            // maybe makes sense; please don't do it anywhere else.
            CWalletDB* pwalletdb = fFileBacked ? new CWalletDB(strWalletFile,"r+") : NULL;

            // Take key pair from key pool so it won't be used again
            reservekey.KeepKey();

            // Add tx to wallet, because if it has change it's also ours,
            // otherwise just for transaction history.
            AddToWallet(wtxNew, false, pwalletdb);

            // Notify that old coins are spent
            set<CWalletTx*> setCoins;
            BOOST_FOREACH(const CTxIn& txin, wtxNew.vin)
            {
                CWalletTx &coin = mapWallet[txin.prevout.hash];
                coin.BindWallet(this);
                NotifyTransactionChanged(this, coin.GetHash(), CT_UPDATED);
            }

            if (fFileBacked)
                delete pwalletdb;
        }

        // Track how many getdata requests our transaction gets
        mapRequestCount[wtxNew.GetHash()] = 0;

        if (fBroadcastTransactions)
        {
            // Broadcast
            if (!wtxNew.AcceptToMemoryPool(false))
            {
                // This must not fail. The transaction has already been signed and recorded.
                LogPrintf("CommitTransaction(): Error: Transaction not valid\n");
                return false;
            }
            wtxNew.RelayWalletTransaction();
        }
    }
    return true;
}

CAmount CWallet::GetMinimumFee(unsigned int nTxBytes, unsigned int nConfirmTarget, const CTxMemPool& pool)
{
    // payTxFee is user-set "I want to pay this much"
    CAmount nFeeNeeded = payTxFee.GetFee(nTxBytes);
    // user selected total at least (default=true)
    if (fPayAtLeastCustomFee && nFeeNeeded > 0 && nFeeNeeded < payTxFee.GetFeePerK())
        nFeeNeeded = payTxFee.GetFeePerK();
    // User didn't set: use -txconfirmtarget to estimate...
    if (nFeeNeeded == 0)
        nFeeNeeded = pool.estimateFee(nConfirmTarget).GetFee(nTxBytes);
    // ... unless we don't have enough mempool data, in which case fall
    // back to a hard-coded fee
    if (nFeeNeeded == 0)
        nFeeNeeded = minTxFee.GetFee(nTxBytes);
    // prevent user from paying a non-sense fee (like 1 satoshi): 0 < fee < minRelayFee
    if (nFeeNeeded < ::minRelayTxFee.GetFee(nTxBytes))
        nFeeNeeded = ::minRelayTxFee.GetFee(nTxBytes);
    // But always obey the maximum
    if (nFeeNeeded > maxTxFee)
        nFeeNeeded = maxTxFee;
    return nFeeNeeded;
}




DBErrors CWallet::LoadWallet(bool& fFirstRunRet)
{
    if (!fFileBacked)
        return DB_LOAD_OK;
    fFirstRunRet = false;
    DBErrors nLoadWalletRet = CWalletDB(strWalletFile,"cr+").LoadWallet(this);
    if (nLoadWalletRet == DB_NEED_REWRITE)
    {
        if (CDB::Rewrite(strWalletFile, "\x04pool"))
        {
            LOCK(cs_wallet);
            setKeyPool.clear();
            // Note: can't top-up keypool here, because wallet is locked.
            // User will be prompted to unlock wallet the next operation
            // that requires a new key.
        }
    }

    if (nLoadWalletRet != DB_LOAD_OK)
        return nLoadWalletRet;
    fFirstRunRet = !vchDefaultKey.IsValid();

    uiInterface.LoadWallet(this);

    return DB_LOAD_OK;
}


DBErrors CWallet::ZapWalletTx(std::vector<CWalletTx>& vWtx)
{
    if (!fFileBacked)
        return DB_LOAD_OK;
    DBErrors nZapWalletTxRet = CWalletDB(strWalletFile,"cr+").ZapWalletTx(this, vWtx);
    if (nZapWalletTxRet == DB_NEED_REWRITE)
    {
        if (CDB::Rewrite(strWalletFile, "\x04pool"))
        {
            LOCK(cs_wallet);
            setKeyPool.clear();
            // Note: can't top-up keypool here, because wallet is locked.
            // User will be prompted to unlock wallet the next operation
            // that requires a new key.
        }
    }

    if (nZapWalletTxRet != DB_LOAD_OK)
        return nZapWalletTxRet;

    return DB_LOAD_OK;
}


bool CWallet::SetAddressBook(const CTxDestination& address, const string& strName, const string& strPurpose)
{
    bool fUpdated = false;
    {
        LOCK(cs_wallet); // mapAddressBook
        std::map<CTxDestination, CAddressBookData>::iterator mi = mapAddressBook.find(address);
        fUpdated = mi != mapAddressBook.end();
        mapAddressBook[address].name = strName;
        if (!strPurpose.empty()) /* update purpose only if requested */
            mapAddressBook[address].purpose = strPurpose;
    }
    NotifyAddressBookChanged(this, address, strName, ::IsMine(*this, address) != ISMINE_NO,
                             strPurpose, (fUpdated ? CT_UPDATED : CT_NEW) );
    if (!fFileBacked)
        return false;
    if (!strPurpose.empty() && !CWalletDB(strWalletFile).WritePurpose(EncodeDestination(address), strPurpose))
        return false;
    return CWalletDB(strWalletFile).WriteName(EncodeDestination(address), strName);
}

bool CWallet::DelAddressBook(const CTxDestination& address)
{
    {
        LOCK(cs_wallet); // mapAddressBook

        if(fFileBacked)
        {
            // Delete destdata tuples associated with address
            std::string strAddress = EncodeDestination(address);
            BOOST_FOREACH(const PAIRTYPE(string, string) &item, mapAddressBook[address].destdata)
            {
                CWalletDB(strWalletFile).EraseDestData(strAddress, item.first);
            }
        }
        mapAddressBook.erase(address);
    }

    NotifyAddressBookChanged(this, address, "", ::IsMine(*this, address) != ISMINE_NO, "", CT_DELETED);

    if (!fFileBacked)
        return false;
    CWalletDB(strWalletFile).ErasePurpose(EncodeDestination(address));
    return CWalletDB(strWalletFile).EraseName(EncodeDestination(address));
}

bool CWallet::SetDefaultKey(const CPubKey &vchPubKey)
{
    if (fFileBacked)
    {
        if (!CWalletDB(strWalletFile).WriteDefaultKey(vchPubKey))
            return false;
    }
    vchDefaultKey = vchPubKey;
    return true;
}

/**
 * Mark old keypool keys as used,
 * and generate all new keys
 */
bool CWallet::NewKeyPool()
{
    {
        LOCK(cs_wallet);
        CWalletDB walletdb(strWalletFile);
        BOOST_FOREACH(int64_t nIndex, setKeyPool)
            walletdb.ErasePool(nIndex);
        setKeyPool.clear();

        if (IsLocked())
            return false;

        int64_t nKeys = max(GetArg("-keypool", 100), (int64_t)0);
        for (int i = 0; i < nKeys; i++)
        {
            int64_t nIndex = i+1;
            walletdb.WritePool(nIndex, CKeyPool(GenerateNewKey()));
            setKeyPool.insert(nIndex);
        }
        LogPrintf("CWallet::NewKeyPool wrote %d new keys\n", nKeys);
    }
    return true;
}

bool CWallet::TopUpKeyPool(unsigned int kpSize)
{
    {
        LOCK(cs_wallet);

        if (IsLocked())
            return false;

        CWalletDB walletdb(strWalletFile);

        // Top up key pool
        unsigned int nTargetSize;
        if (kpSize > 0)
            nTargetSize = kpSize;
        else
            nTargetSize = max(GetArg("-keypool", 100), (int64_t) 0);

        while (setKeyPool.size() < (nTargetSize + 1))
        {
            int64_t nEnd = 1;
            if (!setKeyPool.empty())
                nEnd = *(--setKeyPool.end()) + 1;
            if (!walletdb.WritePool(nEnd, CKeyPool(GenerateNewKey())))
                throw runtime_error("TopUpKeyPool(): writing generated key failed");
            setKeyPool.insert(nEnd);
            LogPrintf("keypool added key %d, size=%u\n", nEnd, setKeyPool.size());
        }
    }
    return true;
}

void CWallet::ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool)
{
    nIndex = -1;
    keypool.vchPubKey = CPubKey();
    {
        LOCK(cs_wallet);

        if (!IsLocked())
            TopUpKeyPool();

        // Get the oldest key
        if(setKeyPool.empty())
            return;

        CWalletDB walletdb(strWalletFile);

        nIndex = *(setKeyPool.begin());
        setKeyPool.erase(setKeyPool.begin());
        if (!walletdb.ReadPool(nIndex, keypool))
            throw runtime_error("ReserveKeyFromKeyPool(): read failed");
        if (!HaveKey(keypool.vchPubKey.GetID()))
            throw runtime_error("ReserveKeyFromKeyPool(): unknown key in key pool");
        assert(keypool.vchPubKey.IsValid());
        LogPrintf("keypool reserve %d\n", nIndex);
    }
}

void CWallet::KeepKey(int64_t nIndex)
{
    // Remove from key pool
    if (fFileBacked)
    {
        CWalletDB walletdb(strWalletFile);
        walletdb.ErasePool(nIndex);
    }
    LogPrintf("keypool keep %d\n", nIndex);
}

void CWallet::ReturnKey(int64_t nIndex)
{
    // Return to key pool
    {
        LOCK(cs_wallet);
        setKeyPool.insert(nIndex);
    }
    LogPrintf("keypool return %d\n", nIndex);
}

bool CWallet::GetKeyFromPool(CPubKey& result)
{
    int64_t nIndex = 0;
    CKeyPool keypool;
    {
        LOCK(cs_wallet);
        ReserveKeyFromKeyPool(nIndex, keypool);
        if (nIndex == -1)
        {
            if (IsLocked()) return false;
            result = GenerateNewKey();
            return true;
        }
        KeepKey(nIndex);
        result = keypool.vchPubKey;
    }
    return true;
}

int64_t CWallet::GetOldestKeyPoolTime()
{
    int64_t nIndex = 0;
    CKeyPool keypool;
    ReserveKeyFromKeyPool(nIndex, keypool);
    if (nIndex == -1)
        return GetTime();
    ReturnKey(nIndex);
    return keypool.nTime;
}

std::map<CTxDestination, CAmount> CWallet::GetAddressBalances()
{
    map<CTxDestination, CAmount> balances;

    {
        LOCK(cs_wallet);
        BOOST_FOREACH(PAIRTYPE(uint256, CWalletTx) walletEntry, mapWallet)
        {
            CWalletTx *pcoin = &walletEntry.second;

            if (!CheckFinalTx(*pcoin) || !pcoin->IsTrusted())
                continue;

            if (pcoin->IsCoinBase() && pcoin->GetBlocksToMaturity() > 0)
                continue;

            int nDepth = pcoin->GetDepthInMainChain();
            if (nDepth < (pcoin->IsFromMe(ISMINE_ALL) ? 0 : 1))
                continue;

            for (unsigned int i = 0; i < pcoin->vout.size(); i++)
            {
                CTxDestination addr;
                if (!IsMine(pcoin->vout[i]))
                    continue;
                if(!ExtractDestination(pcoin->vout[i].scriptPubKey, addr))
                    continue;

                CAmount n = IsSpent(walletEntry.first, i) ? 0 : pcoin->vout[i].nValue;

                if (!balances.count(addr))
                    balances[addr] = 0;
                balances[addr] += n;
            }
        }
    }

    return balances;
}

set< set<CTxDestination> > CWallet::GetAddressGroupings()
{
    AssertLockHeld(cs_wallet); // mapWallet
    set< set<CTxDestination> > groupings;
    set<CTxDestination> grouping;

    BOOST_FOREACH(PAIRTYPE(uint256, CWalletTx) walletEntry, mapWallet)
    {
        CWalletTx *pcoin = &walletEntry.second;

        if (pcoin->vin.size() > 0)
        {
            bool any_mine = false;
            // group all input addresses with each other
            BOOST_FOREACH(CTxIn txin, pcoin->vin)
            {
                CTxDestination address;
                if(!IsMine(txin)) /* If this input isn't mine, ignore it */
                    continue;
                if(!ExtractDestination(mapWallet[txin.prevout.hash].vout[txin.prevout.n].scriptPubKey, address))
                    continue;
                grouping.insert(address);
                any_mine = true;
            }

            // group change with input addresses
            if (any_mine)
            {
               BOOST_FOREACH(CTxOut txout, pcoin->vout)
                   if (IsChange(txout))
                   {
                       CTxDestination txoutAddr;
                       if(!ExtractDestination(txout.scriptPubKey, txoutAddr))
                           continue;
                       grouping.insert(txoutAddr);
                   }
            }
            if (grouping.size() > 0)
            {
                groupings.insert(grouping);
                grouping.clear();
            }
        }

        // group lone addrs by themselves
        for (unsigned int i = 0; i < pcoin->vout.size(); i++)
            if (IsMine(pcoin->vout[i]))
            {
                CTxDestination address;
                if(!ExtractDestination(pcoin->vout[i].scriptPubKey, address))
                    continue;
                grouping.insert(address);
                groupings.insert(grouping);
                grouping.clear();
            }
    }

    set< set<CTxDestination>* > uniqueGroupings; // a set of pointers to groups of addresses
    map< CTxDestination, set<CTxDestination>* > setmap;  // map addresses to the unique group containing it
    BOOST_FOREACH(set<CTxDestination> grouping, groupings)
    {
        // make a set of all the groups hit by this new group
        set< set<CTxDestination>* > hits;
        map< CTxDestination, set<CTxDestination>* >::iterator it;
        BOOST_FOREACH(CTxDestination address, grouping)
            if ((it = setmap.find(address)) != setmap.end())
                hits.insert((*it).second);

        // merge all hit groups into a new single group and delete old groups
        set<CTxDestination>* merged = new set<CTxDestination>(grouping);
        BOOST_FOREACH(set<CTxDestination>* hit, hits)
        {
            merged->insert(hit->begin(), hit->end());
            uniqueGroupings.erase(hit);
            delete hit;
        }
        uniqueGroupings.insert(merged);

        // update setmap
        BOOST_FOREACH(CTxDestination element, *merged)
            setmap[element] = merged;
    }

    set< set<CTxDestination> > ret;
    BOOST_FOREACH(set<CTxDestination>* uniqueGrouping, uniqueGroupings)
    {
        ret.insert(*uniqueGrouping);
        delete uniqueGrouping;
    }

    return ret;
}

std::set<CTxDestination> CWallet::GetAccountAddresses(const std::string& strAccount) const
{
    LOCK(cs_wallet);
    set<CTxDestination> result;
    BOOST_FOREACH(const PAIRTYPE(CTxDestination, CAddressBookData)& item, mapAddressBook)
    {
        const CTxDestination& address = item.first;
        const string& strName = item.second.name;
        if (strName == strAccount)
            result.insert(address);
    }
    return result;
}

bool CReserveKey::GetReservedKey(CPubKey& pubkey)
{
    if (nIndex == -1)
    {
        CKeyPool keypool;
        pwallet->ReserveKeyFromKeyPool(nIndex, keypool);
        if (nIndex != -1)
            vchPubKey = keypool.vchPubKey;
        else {
            return false;
        }
    }
    assert(vchPubKey.IsValid());
    pubkey = vchPubKey;
    return true;
}

void CReserveKey::KeepKey()
{
    if (nIndex != -1)
        pwallet->KeepKey(nIndex);
    nIndex = -1;
    vchPubKey = CPubKey();
}

void CReserveKey::ReturnKey()
{
    if (nIndex != -1)
        pwallet->ReturnKey(nIndex);
    nIndex = -1;
    vchPubKey = CPubKey();
}

void CWallet::GetAllReserveKeys(set<CKeyID>& setAddress) const
{
    setAddress.clear();

    CWalletDB walletdb(strWalletFile);

    LOCK2(cs_main, cs_wallet);
    BOOST_FOREACH(const int64_t& id, setKeyPool)
    {
        CKeyPool keypool;
        if (!walletdb.ReadPool(id, keypool))
            throw runtime_error("GetAllReserveKeyHashes(): read failed");
        assert(keypool.vchPubKey.IsValid());
        CKeyID keyID = keypool.vchPubKey.GetID();
        if (!HaveKey(keyID))
            throw runtime_error("GetAllReserveKeyHashes(): unknown key in key pool");
        setAddress.insert(keyID);
    }
}

void CWallet::UpdatedTransaction(const uint256 &hashTx)
{
    {
        LOCK(cs_wallet);
        // Only notify UI if this transaction is in this wallet
        map<uint256, CWalletTx>::const_iterator mi = mapWallet.find(hashTx);
        if (mi != mapWallet.end())
            NotifyTransactionChanged(this, hashTx, CT_UPDATED);
    }
}

void CWallet::LockCoin(COutPoint& output)
{
    AssertLockHeld(cs_wallet); // setLockedCoins
    setLockedCoins.insert(output);
}

void CWallet::UnlockCoin(COutPoint& output)
{
    AssertLockHeld(cs_wallet); // setLockedCoins
    setLockedCoins.erase(output);
}

void CWallet::UnlockAllCoins()
{
    AssertLockHeld(cs_wallet); // setLockedCoins
    setLockedCoins.clear();
}

bool CWallet::IsLockedCoin(uint256 hash, unsigned int n) const
{
    AssertLockHeld(cs_wallet); // setLockedCoins
    COutPoint outpt(hash, n);

    return (setLockedCoins.count(outpt) > 0);
}

void CWallet::ListLockedCoins(std::vector<COutPoint>& vOutpts)
{
    AssertLockHeld(cs_wallet); // setLockedCoins
    for (std::set<COutPoint>::iterator it = setLockedCoins.begin();
         it != setLockedCoins.end(); it++) {
        COutPoint outpt = (*it);
        vOutpts.push_back(outpt);
    }
}


// Note Locking Operations

void CWallet::LockNote(const JSOutPoint& output)
{
    AssertLockHeld(cs_wallet); // setLockedNotes
    setLockedNotes.insert(output);
}

void CWallet::UnlockNote(const JSOutPoint& output)
{
    AssertLockHeld(cs_wallet); // setLockedNotes
    setLockedNotes.erase(output);
}

void CWallet::UnlockAllNotes()
{
    AssertLockHeld(cs_wallet); // setLockedNotes
    setLockedNotes.clear();
}

bool CWallet::IsLockedNote(const JSOutPoint& outpt) const
{
    AssertLockHeld(cs_wallet); // setLockedNotes

    return (setLockedNotes.count(outpt) > 0);
}

std::vector<JSOutPoint> CWallet::ListLockedNotes()
{
    AssertLockHeld(cs_wallet); // setLockedNotes
    std::vector<JSOutPoint> vOutpts(setLockedNotes.begin(), setLockedNotes.end());
    return vOutpts;
}

/** @} */ // end of Actions

class CAffectedKeysVisitor : public boost::static_visitor<void> {
private:
    const CKeyStore &keystore;
    std::vector<CKeyID> &vKeys;

public:
    CAffectedKeysVisitor(const CKeyStore &keystoreIn, std::vector<CKeyID> &vKeysIn) : keystore(keystoreIn), vKeys(vKeysIn) {}

    void Process(const CScript &script) {
        txnouttype type;
        std::vector<CTxDestination> vDest;
        int nRequired;
        if (ExtractDestinations(script, type, vDest, nRequired)) {
            BOOST_FOREACH(const CTxDestination &dest, vDest)
                boost::apply_visitor(*this, dest);
        }
    }

    void operator()(const CKeyID &keyId) {
        if (keystore.HaveKey(keyId))
            vKeys.push_back(keyId);
    }

    void operator()(const CScriptID &scriptId) {
        CScript script;
        if (keystore.GetCScript(scriptId, script))
            Process(script);
    }

    void operator()(const CNoDestination &none) {}
};

void CWallet::GetKeyBirthTimes(std::map<CKeyID, int64_t> &mapKeyBirth) const {
    AssertLockHeld(cs_wallet); // mapKeyMetadata
    mapKeyBirth.clear();

    // get birth times for keys with metadata
    for (std::map<CKeyID, CKeyMetadata>::const_iterator it = mapKeyMetadata.begin(); it != mapKeyMetadata.end(); it++)
        if (it->second.nCreateTime)
            mapKeyBirth[it->first] = it->second.nCreateTime;

    // map in which we'll infer heights of other keys
    CBlockIndex *pindexMax = chainActive[std::max(0, chainActive.Height() - 144)]; // the tip can be reorganised; use a 144-block safety margin
    std::map<CKeyID, CBlockIndex*> mapKeyFirstBlock;
    std::set<CKeyID> setKeys;
    GetKeys(setKeys);
    BOOST_FOREACH(const CKeyID &keyid, setKeys) {
        if (mapKeyBirth.count(keyid) == 0)
            mapKeyFirstBlock[keyid] = pindexMax;
    }
    setKeys.clear();

    // if there are no such keys, we're done
    if (mapKeyFirstBlock.empty())
        return;

    // find first block that affects those keys, if there are any left
    std::vector<CKeyID> vAffected;
    for (std::map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); it++) {
        // iterate over all wallet transactions...
        const CWalletTx &wtx = (*it).second;
        BlockMap::const_iterator blit = mapBlockIndex.find(wtx.hashBlock);
        if (blit != mapBlockIndex.end() && chainActive.Contains(blit->second)) {
            // ... which are already in a block
            int nHeight = blit->second->nHeight;
            BOOST_FOREACH(const CTxOut &txout, wtx.vout) {
                // iterate over all their outputs
                CAffectedKeysVisitor(*this, vAffected).Process(txout.scriptPubKey);
                BOOST_FOREACH(const CKeyID &keyid, vAffected) {
                    // ... and all their affected keys
                    std::map<CKeyID, CBlockIndex*>::iterator rit = mapKeyFirstBlock.find(keyid);
                    if (rit != mapKeyFirstBlock.end() && nHeight < rit->second->nHeight)
                        rit->second = blit->second;
                }
                vAffected.clear();
            }
        }
    }

    // Extract block timestamps for those keys
    for (std::map<CKeyID, CBlockIndex*>::const_iterator it = mapKeyFirstBlock.begin(); it != mapKeyFirstBlock.end(); it++)
        mapKeyBirth[it->first] = it->second->GetBlockTime() - 7200; // block times can be 2h off
}

bool CWallet::AddDestData(const CTxDestination &dest, const std::string &key, const std::string &value)
{
    if (boost::get<CNoDestination>(&dest))
        return false;

    mapAddressBook[dest].destdata.insert(std::make_pair(key, value));
    if (!fFileBacked)
        return true;
    return CWalletDB(strWalletFile).WriteDestData(EncodeDestination(dest), key, value);
}

bool CWallet::EraseDestData(const CTxDestination &dest, const std::string &key)
{
    if (!mapAddressBook[dest].destdata.erase(key))
        return false;
    if (!fFileBacked)
        return true;
    return CWalletDB(strWalletFile).EraseDestData(EncodeDestination(dest), key);
}

bool CWallet::LoadDestData(const CTxDestination &dest, const std::string &key, const std::string &value)
{
    mapAddressBook[dest].destdata.insert(std::make_pair(key, value));
    return true;
}

bool CWallet::GetDestData(const CTxDestination &dest, const std::string &key, std::string *value) const
{
    std::map<CTxDestination, CAddressBookData>::const_iterator i = mapAddressBook.find(dest);
    if(i != mapAddressBook.end())
    {
        CAddressBookData::StringMap::const_iterator j = i->second.destdata.find(key);
        if(j != i->second.destdata.end())
        {
            if(value)
                *value = j->second;
            return true;
        }
    }
    return false;
}

CKeyPool::CKeyPool()
{
    nTime = GetTime();
}

CKeyPool::CKeyPool(const CPubKey& vchPubKeyIn)
{
    nTime = GetTime();
    vchPubKey = vchPubKeyIn;
}

CWalletKey::CWalletKey(int64_t nExpires)
{
    nTimeCreated = (nExpires ? GetTime() : 0);
    nTimeExpires = nExpires;
}

int CMerkleTx::SetMerkleBranch(const CBlock& block)
{
    AssertLockHeld(cs_main);
    CBlock blockTmp;

    // Update the tx's hashBlock
    hashBlock = block.GetHash();

    // Locate the transaction
    for (nIndex = 0; nIndex < (int)block.vtx.size(); nIndex++)
        if (block.vtx[nIndex] == *(CTransaction*)this)
            break;
    if (nIndex == (int)block.vtx.size())
    {
        vMerkleBranch.clear();
        nIndex = -1;
        LogPrintf("ERROR: SetMerkleBranch(): couldn't find tx in block\n");
        return 0;
    }

    // Fill in merkle branch
    vMerkleBranch = block.GetMerkleBranch(nIndex);

    // Is the tx in a block that's in the main chain
    BlockMap::iterator mi = mapBlockIndex.find(hashBlock);
    if (mi == mapBlockIndex.end())
        return 0;
    const CBlockIndex* pindex = (*mi).second;
    if (!pindex || !chainActive.Contains(pindex))
        return 0;

    return chainActive.Height() - pindex->nHeight + 1;
}

int CMerkleTx::GetDepthInMainChainINTERNAL(const CBlockIndex* &pindexRet) const
{
    if (hashBlock.IsNull() || nIndex == -1)
        return 0;
    AssertLockHeld(cs_main);

    // Find the block it claims to be in
    BlockMap::iterator mi = mapBlockIndex.find(hashBlock);
    if (mi == mapBlockIndex.end())
        return 0;
    CBlockIndex* pindex = (*mi).second;
    if (!pindex || !chainActive.Contains(pindex))
        return 0;

    // Make sure the merkle branch connects to this block
    if (!fMerkleVerified)
    {
        if (CBlock::CheckMerkleBranch(GetHash(), vMerkleBranch, nIndex) != pindex->hashMerkleRoot)
            return 0;
        fMerkleVerified = true;
    }

    pindexRet = pindex;
    return chainActive.Height() - pindex->nHeight + 1;
}

int CMerkleTx::GetDepthInMainChain(const CBlockIndex* &pindexRet) const
{
    AssertLockHeld(cs_main);
    int nResult = GetDepthInMainChainINTERNAL(pindexRet);
    if (nResult == 0 && !mempool.exists(GetHash()))
        return -1; // Not in chain, not in mempool

    return nResult;
}

int CMerkleTx::GetBlocksToMaturity() const
{
    if (!IsCoinBase())
        return 0;
    return max(0, (COINBASE_MATURITY+1) - GetDepthInMainChain());
}


bool CMerkleTx::AcceptToMemoryPool(bool fLimitFree, bool fRejectAbsurdFee)
{
    CValidationState state;
    return ::AcceptToMemoryPool(mempool, state, *this, fLimitFree, NULL, fRejectAbsurdFee);
}

/**
 * Find notes in the wallet filtered by payment address, min depth and ability to spend.
 * These notes are decrypted and added to the output parameter vector, outEntries.
 */
void CWallet::GetFilteredNotes(std::vector<CSproutNotePlaintextEntry> & outEntries, std::string address, int minDepth, bool ignoreSpent, bool ignoreUnspendable)
{
    std::set<PaymentAddress> filterAddresses;

    if (address.length() > 0) {
        filterAddresses.insert(DecodePaymentAddress(address));
    }

    GetFilteredNotes(outEntries, filterAddresses, minDepth, ignoreSpent, ignoreUnspendable);
}

/**
 * Find notes in the wallet filtered by payment addresses, min depth and ability to spend.
 * These notes are decrypted and added to the output parameter vector, outEntries.
 */
void CWallet::GetFilteredNotes(
    std::vector<CSproutNotePlaintextEntry>& outEntries,
    std::set<PaymentAddress>& filterAddresses,
    int minDepth,
    bool ignoreSpent,
    bool ignoreUnspendable)
{
    LOCK2(cs_main, cs_wallet);

    for (auto & p : mapWallet) {
        CWalletTx wtx = p.second;

        // Filter the transactions before checking for notes
        if (!CheckFinalTx(wtx) || wtx.GetBlocksToMaturity() > 0 || wtx.GetDepthInMainChain() < minDepth) {
            continue;
        }

        if (wtx.mapSproutNoteData.size() == 0) {
            continue;
        }

        for (auto & pair : wtx.mapSproutNoteData) {
            JSOutPoint jsop = pair.first;
            SproutNoteData nd = pair.second;
            SproutPaymentAddress pa = nd.address;

            // skip notes which belong to a different payment address in the wallet
            if (!(filterAddresses.empty() || filterAddresses.count(pa))) {
                continue;
            }

            // skip note which has been spent
            if (ignoreSpent && nd.nullifier && IsSpent(*nd.nullifier)) {
                continue;
            }

            // skip notes which cannot be spent
            if (ignoreUnspendable && !HaveSproutSpendingKey(pa)) {
                continue;
            }

            // skip locked notes
            if (IsLockedNote(jsop)) {
                continue;
            }

            int i = jsop.js; // Index into CTransaction.vjoinsplit
            int j = jsop.n; // Index into JSDescription.ciphertexts

            // Get cached decryptor
            ZCNoteDecryption decryptor;
            if (!GetNoteDecryptor(pa, decryptor)) {
                // Note decryptors are created when the wallet is loaded, so it should always exist
                throw std::runtime_error(strprintf("Could not find note decryptor for payment address %s", EncodePaymentAddress(pa)));
            }

            // determine amount of funds in the note
            auto hSig = wtx.vjoinsplit[i].h_sig(*pzcashParams, wtx.joinSplitPubKey);
            try {
                SproutNotePlaintext plaintext = SproutNotePlaintext::decrypt(
                        decryptor,
                        wtx.vjoinsplit[i].ciphertexts[j],
                        wtx.vjoinsplit[i].ephemeralKey,
                        hSig,
                        (unsigned char) j);

                outEntries.push_back(CSproutNotePlaintextEntry{jsop, pa, plaintext});

            } catch (const note_decryption_failed &err) {
                // Couldn't decrypt with this spending key
                throw std::runtime_error(strprintf("Could not decrypt note for payment address %s", EncodePaymentAddress(pa)));
            } catch (const std::exception &exc) {
                // Unexpected failure
                throw std::runtime_error(strprintf("Error while decrypting note for payment address %s: %s", EncodePaymentAddress(pa), exc.what()));
            }
        }
    }
}


/* Find unspent notes filtered by payment address, min depth and max depth */
void CWallet::GetUnspentFilteredNotes(
    std::vector<CUnspentSproutNotePlaintextEntry>& outEntries,
    std::set<PaymentAddress>& filterAddresses,
    int minDepth,
    int maxDepth,
    bool requireSpendingKey)
{
    LOCK2(cs_main, cs_wallet);

    for (auto & p : mapWallet) {
        CWalletTx wtx = p.second;

        // Filter the transactions before checking for notes
        if (!CheckFinalTx(wtx) || wtx.GetBlocksToMaturity() > 0 || wtx.GetDepthInMainChain() < minDepth || wtx.GetDepthInMainChain() > maxDepth) {
            continue;
        }

        if (wtx.mapSproutNoteData.size() == 0) {
            continue;
        }

        for (auto & pair : wtx.mapSproutNoteData) {
            JSOutPoint jsop = pair.first;
            SproutNoteData nd = pair.second;
            SproutPaymentAddress pa = nd.address;

            // skip notes which belong to a different payment address in the wallet
            if (!(filterAddresses.empty() || filterAddresses.count(pa))) {
                continue;
            }

            // skip note which has been spent
            if (nd.nullifier && IsSpent(*nd.nullifier)) {
                continue;
            }

            // skip notes where the spending key is not available
            if (requireSpendingKey && !HaveSproutSpendingKey(pa)) {
                continue;
            }

            int i = jsop.js; // Index into CTransaction.vjoinsplit
            int j = jsop.n; // Index into JSDescription.ciphertexts

            // Get cached decryptor
            ZCNoteDecryption decryptor;
            if (!GetNoteDecryptor(pa, decryptor)) {
                // Note decryptors are created when the wallet is loaded, so it should always exist
                throw std::runtime_error(strprintf("Could not find note decryptor for payment address %s", EncodePaymentAddress(pa)));
            }

            // determine amount of funds in the note
            auto hSig = wtx.vjoinsplit[i].h_sig(*pzcashParams, wtx.joinSplitPubKey);
            try {
                SproutNotePlaintext plaintext = SproutNotePlaintext::decrypt(
                        decryptor,
                        wtx.vjoinsplit[i].ciphertexts[j],
                        wtx.vjoinsplit[i].ephemeralKey,
                        hSig,
                        (unsigned char) j);

                outEntries.push_back(CUnspentSproutNotePlaintextEntry{jsop, pa, plaintext, wtx.GetDepthInMainChain()});

            } catch (const note_decryption_failed &err) {
                // Couldn't decrypt with this spending key
                throw std::runtime_error(strprintf("Could not decrypt note for payment address %s", EncodePaymentAddress(pa)));
            } catch (const std::exception &exc) {
                // Unexpected failure
                throw std::runtime_error(strprintf("Error while decrypting note for payment address %s: %s", EncodePaymentAddress(pa), exc.what()));
            }
        }
    }
}