rpcblockchain.go

package rpc

import (
	"bytes"
	"encoding/hex"
	"fmt"
	"math"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/copernet/copernicus/conf"
	"github.com/copernet/copernicus/log"
	"github.com/copernet/copernicus/logic/lchain"
	"github.com/copernet/copernicus/logic/lmempool"
	"github.com/copernet/copernicus/model"
	"github.com/copernet/copernicus/model/block"
	"github.com/copernet/copernicus/model/blockindex"
	"github.com/copernet/copernicus/model/chain"
	"github.com/copernet/copernicus/model/consensus"
	"github.com/copernet/copernicus/model/mempool"
	"github.com/copernet/copernicus/model/outpoint"
	"github.com/copernet/copernicus/model/tx"
	"github.com/copernet/copernicus/model/utxo"
	"github.com/copernet/copernicus/model/versionbits"
	"github.com/copernet/copernicus/persist"
	"github.com/copernet/copernicus/persist/disk"
	"github.com/copernet/copernicus/rpc/btcjson"
	"github.com/copernet/copernicus/util"
	"gopkg.in/fatih/set.v0"
)

var blockchainHandlers = map[string]commandHandler{
	"getblockchaininfo":     handleGetBlockChainInfo,
	"getbestblockhash":      handleGetBestBlockHash,      // complete
	"getblockcount":         handleGetBlockCount,         // complete
	"getblock":              handleGetBlock,              // complete
	"getblockhash":          handleGetBlockHash,          // complete
	"getblockheader":        handleGetBlockHeader,        // complete
	"getchaintips":          handleGetChainTips,          // partial complete
	"getdifficulty":         handleGetDifficulty,         //complete
	"getchaintxstats":       handleGetChainTxStats,       // complete
	"getmempoolancestors":   handleGetMempoolAncestors,   // complete
	"getmempooldescendants": handleGetMempoolDescendants, //complete
	"getmempoolentry":       handleGetMempoolEntry,       // complete
	"getmempoolinfo":        handleGetMempoolInfo,        // complete
	"getrawmempool":         handleGetRawMempool,         // complete
	"gettxout":              handleGetTxOut,              // complete
	"gettxoutsetinfo":       handleGetTxoutSetInfo,
	"pruneblockchain":       handlePruneBlockChain, //complete
	"verifychain":           handleVerifyChain,     //complete
	"preciousblock":         handlePreciousblock,   //complete

	/*not shown in help*/
	"invalidateblock":    handleInvalidateBlock, //complete
	"reconsiderblock":    handleReconsiderBlock, //complete
	"waitfornewblock":    handleWaitForNewBlock,
	"waitforblock":       handleWaitForBlock,
	"waitforblockheight": handleWaitForBlockHeight,
}

func handleGetBlockChainInfo(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	gChain := chain.GetInstance()
	params := gChain.GetParams()
	tip := gChain.Tip()

	chainInfo := &btcjson.GetBlockChainInfoResult{
		Chain:                params.Name,
		Blocks:               gChain.Height(),
		Headers:              gChain.Height(), // TODO: NOT support header-first yet
		BestBlockHash:        tip.GetBlockHash().String(),
		Difficulty:           getDifficulty(tip),
		MedianTime:           tip.GetMedianTimePast(),
		VerificationProgress: lchain.GuessVerificationProgress(params.TxData(), tip),
		ChainWork:            fmt.Sprintf("%064x", &tip.ChainWork),
		Pruned:               false,
		Bip9SoftForks:        make(map[string]*btcjson.Bip9SoftForkDescription),
	}

	// Next, populate the response with information describing the current
	// status of soft-forks deployed via the super-majority block
	// signalling mechanism.

	height := tip.Height
	chainInfo.SoftForks = version234Status(height, params)

	// Finally, query the BIP0009 version bits state for all currently
	// defined BIP0009 soft-fork deployments.
	for i := 0; i < int(consensus.MaxVersionBitsDeployments); i++ {
		pos := consensus.DeploymentPos(i)
		state := versionbits.VersionBitsState(tip, params, pos, versionbits.VBCache)
		forkName := getVbName(pos)

		// Attempt to convert the current deployment status into a
		// human readable string. If the status is unrecognized, then a
		// non-nil error is returned.
		statusString, err := softForkStatus(state)
		if err != nil {
			return nil, &btcjson.RPCError{
				Code: btcjson.ErrRPCInternal.Code,
				Message: fmt.Sprintf("unknown deployment status: %v",
					state),
			}
		}

		// Finally, populate the soft-fork description with all the
		// information gathered above.
		deploymentDetails := &params.Deployments[pos]
		chainInfo.Bip9SoftForks[forkName] = &btcjson.Bip9SoftForkDescription{
			Status:    strings.ToLower(statusString),
			Bit:       uint8(deploymentDetails.Bit),
			StartTime: deploymentDetails.StartTime,
			Timeout:   deploymentDetails.Timeout,
			Since:     int32(versionbits.VersionBitsStateSinceHeight(tip, params, pos, versionbits.VBCache)),
		}
	}

	return chainInfo, nil
}

func version234Status(height int32, params *model.BitcoinParams) []*btcjson.SoftForkDescription {
	return []*btcjson.SoftForkDescription{
		{
			ID:      "bip34",
			Version: 2,
			Reject: struct {
				Status bool `json:"status"`
			}{
				Status: height >= params.BIP34Height,
			},
		},
		{
			ID:      "bip66",
			Version: 3,
			Reject: struct {
				Status bool `json:"status"`
			}{
				Status: height >= params.BIP66Height,
			},
		},
		{
			ID:      "bip65",
			Version: 4,
			Reject: struct {
				Status bool `json:"status"`
			}{
				Status: height >= params.BIP65Height,
			},
		},
		{
			ID:      "csv",
			Version: 5,
			Reject: struct {
				Status bool `json:"status"`
			}{
				Status: height >= params.CSVHeight,
			},
		},
	}
}

// softForkStatus converts a ThresholdState state into a human readable string
// corresponding to the particular state.
func softForkStatus(state versionbits.ThresholdState) (string, error) {
	switch state {
	case versionbits.ThresholdDefined:
		return "defined", nil
	case versionbits.ThresholdStarted:
		return "started", nil
	case versionbits.ThresholdLockedIn:
		return "locked_in", nil
	case versionbits.ThresholdActive:
		return "active", nil
	case versionbits.ThresholdFailed:
		return "failed", nil
	default:
		return "", fmt.Errorf("unknown deployment state: %v", state)
	}
}

func handleGetBestBlockHash(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	return chain.GetInstance().Tip().GetBlockHash().String(), nil
}

func handleGetBlockCount(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	return chain.GetInstance().Height(), nil
}

func handleGetBlock(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c := cmd.(*btcjson.GetBlockCmd)

	// Load the raw block bytes from the database.
	hash, err := util.GetHashFromStr(c.Hash)
	if err != nil {
		return nil, rpcDecodeHexError(c.Hash)
	}

	blockIndex := chain.GetInstance().FindBlockIndex(*hash)
	if blockIndex == nil {
		return false, &btcjson.RPCError{
			Code:    btcjson.ErrRPCInvalidAddressOrKey,
			Message: "Block not found",
		}
	}

	pruneState := disk.GetPruneState()
	if pruneState.HavePruned && !blockIndex.HasData() && blockIndex.TxCount > 0 {
		return false, &btcjson.RPCError{
			Code:    btcjson.ErrRPCMisc,
			Message: "Block not available (pruned data)",
		}
	}

	blk, ret := disk.ReadBlockFromDisk(blockIndex, chain.GetInstance().GetParams())
	if !ret {
		return false, &btcjson.RPCError{
			Code:    btcjson.ErrRPCMisc,
			Message: "Block not found on disk",
		}
	}

	if c.Verbose != nil && !*c.Verbose {
		blkBuf := bytes.NewBuffer(nil)
		blk.Serialize(blkBuf)
		strHex := hex.EncodeToString(blkBuf.Bytes())
		return strHex, nil
	}

	blockReply := blockToJSON(blk, blockIndex)

	return blockReply, nil
}

func blockToJSON(blk *block.Block, blockIndex *blockindex.BlockIndex) *btcjson.GetBlockVerboseResult {
	confirmations := int32(-1)
	// Only report confirmations if the block is on the main chain
	if chain.GetInstance().Contains(blockIndex) {
		confirmations = chain.GetInstance().TipHeight() - blockIndex.Height + 1
	}

	var previousHash string
	if blockIndex.Prev != nil {
		previousHash = blockIndex.Prev.GetBlockHash().String()
	}

	var nextHash string
	next := chain.GetInstance().Next(blockIndex)
	if next != nil {
		nextHash = next.GetBlockHash().String()
	}

	blockHeader := &blk.Header
	blockReply := &btcjson.GetBlockVerboseResult{
		Hash:          blockIndex.GetBlockHash().String(),
		Confirmations: confirmations,
		Size:          blk.SerializeSize(),
		Height:        blockIndex.Height,
		Version:       blockHeader.Version,
		VersionHex:    fmt.Sprintf("%08x", blockHeader.Version),
		MerkleRoot:    blockHeader.MerkleRoot.String(),
		Tx:            make([]string, len(blk.Txs)),
		Time:          int64(blockHeader.Time),
		Mediantime:    blockIndex.GetMedianTimePast(),
		Nonce:         blockHeader.Nonce,
		Bits:          fmt.Sprintf("%08x", blockHeader.Bits),
		Difficulty:    getDifficulty(blockIndex),
		ChainWork:     fmt.Sprintf("%064x", &blockIndex.ChainWork),
		PreviousHash:  previousHash,
		NextHash:      nextHash,
	}

	for i, tx := range blk.Txs {
		txHash := tx.GetHash()
		blockReply.Tx[i] = txHash.String()
	}
	return blockReply
}

func handleGetBlockHash(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c := cmd.(*btcjson.GetBlockHashCmd)

	blockIndex := chain.GetInstance().GetIndex(c.Height)
	if blockIndex == nil {
		return nil, &btcjson.RPCError{
			Code:    btcjson.ErrRPCOutOfRange,
			Message: "Block height out of range",
		}
	}
	return blockIndex.GetBlockHash().String(), nil
}

func handleGetBlockHeader(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c := cmd.(*btcjson.GetBlockHeaderCmd)

	// Fetch the header from chain.
	hash, err := util.GetHashFromStr(c.Hash)
	if err != nil {
		return nil, &btcjson.RPCError{
			Code:    btcjson.ErrRPCBlockNotFound,
			Message: "Block not found",
		}
	}
	blockIndex := chain.GetInstance().FindBlockIndex(*hash)

	if blockIndex == nil {
		return nil, &btcjson.RPCError{
			Code:    btcjson.ErrRPCBlockNotFound,
			Message: "Block not found",
		}
	}

	// When the verbose flag is set false
	if c.Verbose != nil && !*c.Verbose {
		var headerBuf bytes.Buffer
		err := blockIndex.Header.Serialize(&headerBuf)
		if err != nil {
			context := "Failed to serialize block header"
			return nil, internalRPCError(err.Error(), context)
		}
		return hex.EncodeToString(headerBuf.Bytes()), nil
	}

	confirmations := int32(-1)
	// Only report confirmations if the block is on the main chain
	if chain.GetInstance().Contains(blockIndex) {
		confirmations = chain.GetInstance().TipHeight() - blockIndex.Height + 1
	}

	var previousblockhash string
	if blockIndex.Prev != nil {
		previousblockhash = blockIndex.Prev.GetBlockHash().String()
	}

	var nextblockhash string
	next := chain.GetInstance().Next(blockIndex)
	if next != nil {
		nextblockhash = next.GetBlockHash().String()
	}

	blockHeaderReply := &btcjson.GetBlockHeaderVerboseResult{
		Hash:          c.Hash,
		Confirmations: uint64(confirmations),
		Height:        blockIndex.Height,
		Version:       blockIndex.Header.Version,
		VersionHex:    fmt.Sprintf("%08x", blockIndex.Header.Version),
		MerkleRoot:    blockIndex.Header.MerkleRoot.String(),
		Time:          blockIndex.Header.Time,
		Mediantime:    blockIndex.GetMedianTimePast(),
		Nonce:         uint64(blockIndex.Header.Nonce),
		Bits:          fmt.Sprintf("%08x", blockIndex.Header.Bits),
		Difficulty:    getDifficulty(blockIndex),
		Chainwork:     fmt.Sprintf("%064x", &blockIndex.ChainWork),
		PreviousHash:  previousblockhash,
		NextHash:      nextblockhash,
	}
	return blockHeaderReply, nil
}

func handleGetChainTips(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	// Idea:  the set of chain tips is chainActive.tip, plus orphan blocks which
	// do not have another orphan building off of them.
	// Algorithm:
	//	- Make one pass through mapBlockIndex, picking out the orphan blocks,
	//	  and also storing a set of the orphan block's pprev pointers.
	//  - Iterate through the orphan blocks. If the block isn't pointed to by
	//	  another orphan, it is a chain tip.
	//	- add chainActive.Tip()
	setTips := set.New() // element type:
	gchain := chain.GetInstance()

	setTips = gchain.GetChainTips()

	tips := make([]btcjson.ChainTipsInfo, 0, setTips.Size())

	setTips.Each(func(item interface{}) bool {
		bindex := item.(*blockindex.BlockIndex)
		tipInfo := btcjson.ChainTipsInfo{
			Height:    bindex.Height,
			Hash:      bindex.GetBlockHash().String(),
			BranchLen: bindex.Height - chain.GetInstance().FindFork(bindex).Height,
		}

		var status string
		if chain.GetInstance().Contains(bindex) {
			// This block is part of the currently active chain.
			status = "active"
		} else if bindex.IsInvalid() {
			// This block or one of its ancestors is invalid.
			status = "invalid"
		} else if bindex.ChainTxCount == 0 {
			// This block cannot be connected because full block data for it or
			// one of its parents is missing.
			status = "headers-only"
		} else if bindex.IsValid(blockindex.BlockValidScripts) {
			// This block is fully validated, but no longer part of the active
			// chain. It was probably the active block once, but was
			// reorganized.
			status = "valid-fork"
		} else if bindex.IsValid(blockindex.BlockValidTree) {
			// The headers for this block are valid, but it has not been
			// validated. It was probably never part of the most-work chain.
			status = "valid-headers"
		} else {
			// No clue
			status = "unknown"
		}
		tipInfo.Status = status

		tips = append(tips, tipInfo)

		return true
	})

	sort.Slice(tips, func(i, j int) bool {
		if tips[i].Height != tips[j].Height {
			return tips[i].Height > tips[j].Height
		}

		return i < j
	})

	return tips, nil
}

func getDifficulty(bi *blockindex.BlockIndex) float64 {
	if bi == nil {
		return 1.0
	}
	return getDifficultyFromBits(bi.GetBlockHeader().Bits)
}

// getDifficultyRatio returns the proof-of-work difficulty as a multiple of the
// minimum difficulty using the passed bits field from the header of a block.
func getDifficultyFromBits(bits uint32) float64 {
	shift := (bits >> 24) & 0xff
	diff := float64(0x0000ffff) / float64(bits&0x00ffffff)
	const factor = float64(256.0)

	for shift < 29 {
		diff *= factor
		shift++
	}

	for shift > 29 {
		diff /= factor
		shift--
	}

	return diff
}

func handleGetDifficulty(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	best := chain.GetInstance().Tip()
	return getDifficulty(best), nil
}

func handleGetChainTxStats(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c := cmd.(*btcjson.GetChainTxStatsCmd)

	gChan := chain.GetInstance()
	blockIndex := gChan.Tip()
	if c.BlockHash != nil {
		blockHash, err := util.GetHashFromStr(*c.BlockHash)
		if err != nil {
			return nil, rpcDecodeHexError(*c.BlockHash)
		}
		blockIndex = gChan.FindBlockIndex(*blockHash)
		if blockIndex == nil {
			return false, &btcjson.RPCError{
				Code:    btcjson.ErrRPCBlockNotFound,
				Message: "Block not found",
			}
		}
		if !gChan.Contains(blockIndex) {
			return false, &btcjson.RPCError{
				Code:    btcjson.ErrRPCInvalidParameter,
				Message: "Block is not in main chain",
			}
		}
	}

	var blockCount int32
	maxCount := util.MaxI32(0, blockIndex.Height-1)
	if c.Blocks != nil {
		blockCount = *c.Blocks
		if blockCount < 0 || blockCount > maxCount {
			return false, &btcjson.RPCError{
				Code:    btcjson.ErrRPCInvalidParameter,
				Message: "Invalid block count: should be between 0 and the block's height - 1",
			}
		}
	} else {
		// By default: 1 month
		blockCount = int32(30 * 24 * 60 * 60 / chain.GetInstance().GetParams().TargetTimePerBlock)
		blockCount = util.MinI32(blockCount, maxCount)
	}

	chainTxStatsReply := &btcjson.GetChainTxStatsResult{
		FinalTime:  blockIndex.GetBlockTime(),
		TxCount:    blockIndex.ChainTxCount,
		BlockCount: blockCount,
	}
	if blockCount > 0 {
		indexPast := blockIndex.GetAncestor(blockIndex.Height - blockCount)
		txDiff := blockIndex.ChainTxCount - indexPast.ChainTxCount
		timeDiff := blockIndex.GetMedianTimePast() - indexPast.GetMedianTimePast()
		chainTxStatsReply.WindowTxCount = txDiff
		chainTxStatsReply.WindowInterval = timeDiff
		if timeDiff > 0 {
			txRate := float64(txDiff) / float64(timeDiff)
			chainTxStatsReply.TxRate = txRate
		}
	}
	return chainTxStatsReply, nil
}

func handleGetMempoolAncestors(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c := cmd.(*btcjson.GetMempoolAncestorsCmd)
	hash, err := util.GetHashFromStr(c.TxID)
	if err != nil {
		return nil, btcjson.RPCError{
			Code:    btcjson.ErrRPCInvalidParameter,
			Message: "the string " + c.TxID + " is not a standard hash",
		}
	}
	entry := mempool.GetInstance().FindTx(*hash)
	if entry == nil {
		return nil, btcjson.RPCError{
			Code:    btcjson.RPCInvalidAddressOrKey,
			Message: "Transaction not in mempool",
		}
	}

	h := entry.Tx.GetHash()
	txSet := mempool.GetInstance().CalculateMemPoolAncestorsWithLock(&h)

	if c.Verbose == nil || !*c.Verbose {
		s := make([]string, len(txSet))
		i := 0
		for index := range txSet {
			hash := index.Tx.GetHash()
			s[i] = hash.String()
			i++
		}
		return s, nil
	}

	infos := make(map[string]*btcjson.GetMempoolEntryRelativeInfoVerbose)
	for index := range txSet {
		hash := index.Tx.GetHash()
		infos[hash.String()] = entryToJSON(index)
	}
	return infos, nil
}

func entryToJSON(entry *mempool.TxEntry) *btcjson.GetMempoolEntryRelativeInfoVerbose {
	result := btcjson.GetMempoolEntryRelativeInfoVerbose{}
	result.Size = entry.TxSize
	result.Fee = valueFromAmount(entry.TxFee)
	result.ModifiedFee = valueFromAmount(entry.SumTxFeeWithAncestors) // todo check: GetModifiedFee() is equal to SumFeeWithAncestors
	result.Time = entry.GetTime()
	result.Height = entry.TxHeight
	// remove priority at current version
	result.StartingPriority = 0
	result.CurrentPriority = 0
	result.DescendantCount = entry.SumTxCountWithDescendants
	result.DescendantSize = entry.SumTxSizeWithDescendants
	result.DescendantFees = entry.SumTxFeeWithDescendants
	result.AncestorCount = entry.SumTxCountWithAncestors
	result.AncestorSize = entry.SumTxSizeWitAncestors
	result.AncestorFees = entry.SumTxFeeWithAncestors

	setDepends := make([]string, 0)
	for _, in := range entry.Tx.GetIns() {
		if txItem := mempool.GetInstance().FindTx(in.PreviousOutPoint.Hash); txItem != nil {
			setDepends = append(setDepends, in.PreviousOutPoint.Hash.String())
		}
	}
	result.Depends = setDepends

	return &result
}

func handleGetMempoolDescendants(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c := cmd.(*btcjson.GetMempoolDescendantsCmd)

	hash, err := util.GetHashFromStr(c.TxID)
	if err != nil {
		return nil, rpcDecodeHexError(c.TxID)
	}

	entry := mempool.GetInstance().FindTx(*hash)
	if entry == nil {
		return nil, btcjson.RPCError{
			Code:    btcjson.RPCInvalidAddressOrKey,
			Message: "Transaction not in mempool",
		}
	}

	descendants := mempool.GetInstance().CalculateDescendantsWithLock(hash)
	// CTxMemPool::CalculateDescendants will include the given tx
	delete(descendants, entry)

	if c.Verbose == nil || !*c.Verbose {
		des := make([]string, 0)
		for item := range descendants {
			hash := item.Tx.GetHash()
			des = append(des, hash.String())
		}
		return des, nil
	}

	infos := make(map[string]*btcjson.GetMempoolEntryRelativeInfoVerbose, len(descendants))
	for item := range descendants {
		h := item.Tx.GetHash()
		infos[h.String()] = entryToJSON(item)
	}
	return infos, nil
}

func handleGetMempoolEntry(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c := cmd.(*btcjson.GetMempoolEntryCmd)

	hash, err := util.GetHashFromStr(c.TxID)
	if err != nil {
		return nil, rpcDecodeHexError(c.TxID)
	}

	entry := mempool.GetInstance().FindTx(*hash)
	if entry == nil {
		return nil, btcjson.RPCError{
			Code:    btcjson.ErrRPCInvalidAddressOrKey,
			Message: "Transaction not in mempool",
		}
	}

	return entryToJSON(entry), nil
}

func handleGetMempoolInfo(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	pool := mempool.GetInstance()
	ret := &btcjson.GetMempoolInfoResult{
		Size:          pool.Size(),
		Bytes:         pool.GetPoolAllTxSize(true),
		Usage:         pool.GetPoolUsage(),
		MaxMempool:    int(conf.Cfg.Mempool.MaxPoolSize),
		MempoolMinFee: valueFromAmount(pool.GetMinFeeRate().SataoshisPerK),
	}
	return ret, nil
}

func valueFromAmount(sizeLimit int64) float64 {
	var nAbs int64
	var strFormat string
	if sizeLimit < 0 {
		nAbs = -sizeLimit
		strFormat = "-%d.%08d"
	} else {
		nAbs = sizeLimit
		strFormat = "%d.%08d"
	}

	quotient := nAbs / util.COIN
	remainder := nAbs % util.COIN
	strValue := fmt.Sprintf(strFormat, quotient, remainder)

	result, err := strconv.ParseFloat(strValue, 64)
	if err != nil {
		return 0
	}
	return result
}

func handleGetRawMempool(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c := cmd.(*btcjson.GetRawMempoolCmd)

	pool := mempool.GetInstance()

	if c.Verbose != nil && *c.Verbose {
		infos := make(map[string]*btcjson.GetMempoolEntryRelativeInfoVerbose)
		for hash, entry := range pool.GetAllTxEntry() {
			infos[hash.String()] = entryToJSON(entry)
		}
		return infos, nil
	}

	// The response is simply an array of the transaction hashes if the verbose flag is not set.
	txAll := pool.TxInfoAll()
	txIds := make([]string, 0, len(txAll))
	for _, txInfo := range txAll {
		txHash := txInfo.Tx.GetHash()
		txIds = append(txIds, txHash.String())
	}

	return txIds, nil
}

func handleGetTxOut(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c := cmd.(*btcjson.GetTxOutCmd)

	// Convert the provided transaction hash hex to a Hash.
	hash, err := util.GetHashFromStr(c.Txid)
	if err != nil {
		return nil, rpcDecodeHexError(c.Txid)
	}

	outPoint := outpoint.NewOutPoint(*hash, c.Vout)
	coinView := utxo.GetUtxoCacheInstance()

	coin := coinView.GetCoin(outPoint)
	if coin == nil {
		if c.IncludeMempool == nil || *c.IncludeMempool {
			coin = mempool.GetInstance().GetCoin(outPoint)
			if coin == nil || mempool.GetInstance().HasSpentOut(outPoint) {
				return nil, nil
			}
		} else {
			return nil, nil
		}
	}

	bestHash, err := coinView.GetBestBlock()
	if err != nil {
		return nil, &btcjson.RPCError{
			Code:    btcjson.ErrRPCNoNewestBlockInfo,
			Message: "Cannot get best block",
		}
	}
	index := chain.GetInstance().FindBlockIndex(bestHash)

	confirmations := int32(0)
	if !coin.IsMempoolCoin() {
		confirmations = index.Height - coin.GetHeight() + 1
	}

	amountValue := valueFromAmount(int64(coin.GetAmount()))
	scriptPubKeyJSON := ScriptPubKeyToJSON(coin.GetScriptPubKey(), true)
	txOutReply := &btcjson.GetTxOutResult{
		BestBlock:     index.GetBlockHash().String(),
		Confirmations: confirmations,
		Value:         strconv.FormatFloat(amountValue, 'f', -1, 64),
		ScriptPubKey:  *scriptPubKeyJSON,
		Coinbase:      coin.IsCoinBase(),
	}

	return txOutReply, nil
}

func handleGetTxoutSetInfo(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	// Write the chain state to disk, if necessary.
	if err := disk.FlushStateToDisk(disk.FlushStateAlways, 0); err != nil {
		return nil, err
	}

	cdb := utxo.GetUtxoCacheInstance().(*utxo.CoinsLruCache).GetCoinsDB()
	stat, err := lchain.GetUTXOStats(cdb)
	if err != nil {
		return nil, err
	}

	reply := &btcjson.GetTxOutSetInfoResult{
		Height:         stat.Height,
		BestBlock:      stat.BestBlock.String(),
		Transactions:   stat.TxCount,
		TxOuts:         stat.TxOutsCount,
		BogoSize:       stat.BogoSize,
		HashSerialized: stat.HashSerialized.String(),
		DiskSize:       stat.DiskSize,
		TotalAmount:    valueFromAmount(stat.Amount),
	}
	return reply, nil
}

func getPrunMode() (bool, error) {
	/*	pruneArg := util.GetArg("-prune", 0)
		if pruneArg < 0 {
			return false, errors.New("Prune cannot be configured with a negative value")
		}*/ // todo open
	return true, nil
}

func handlePruneBlockChain(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	/*	pruneMode, err := getPrunMode()

		if err != nil && !pruneMode {
			return false, &btcjson.RPCError{
				Code:    btcjson.ErrRPCType,
				Message: fmt.Sprintf("Cannot prune blocks because node is not in prune mode."),
			}
		}

		c := cmd.(*btcjson.PruneBlockChainCmd)
		height := c.Height
		if *height < 0 {
			return false, &btcjson.RPCError{
				Code:    btcjson.ErrRPCType,
				Message: fmt.Sprintf("Negative block height."),
			}
		}

		if *height > 1000000000 {
			index := chain.GetInstance().FindEarliestAtLeast(int64(*height - 72000))
			if index != nil {
				return false, &btcjson.RPCError{
					Code:    btcjson.ErrRPCType,
					Message: fmt.Sprintf("Could not find block with at least the specified timestamp."),
				}
			}
			height = &index.Height
		}

		h := *height
		chainHeight := chain.GetInstance().Height()
		if chainHeight < consensus.ActiveNetParams.PruneAfterHeight {
			return false, &btcjson.RPCError{
				Code:    btcjson.ErrRPCMisc,
				Message: fmt.Sprintf("Blockchain is too short for pruning."),
			}
		} else if h > chainHeight {
			return false, &btcjson.RPCError{
				Code:    btcjson.ErrRPCInvalidParameter,
				Message: fmt.Sprintf("Blockchain is shorter than the attempted prune height."),
			}
		} /*else if h > chainHeight - MIN_BLOCKS_TO_KEEP {
			h = chainHeight - MIN_BLOCKS_TO_KEEP
		}

		chain.PruneBlockFilesManual(*height)
		return uint64(*height), nil*/ // todo realise

	return nil, nil
}

// handleVerifyChain implements the verifychain command.
func handleVerifyChain(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	/*	c := cmd.(*btcjson.VerifyChainCmd)

		var checkLevel, checkDepth int32
		if c.CheckLevel != nil {
			checkLevel = *c.CheckLevel
		}
		if c.CheckDepth != nil {
			checkDepth = *c.CheckDepth
		}

		return VerifyDB(consensus.ActiveNetParams, utxo.GetUtxoCacheInstance(), checkLevel, checkDepth), nil*/ // todo open
	return nil, nil
}

func handlePreciousblock(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	/*	c := cmd.(*btcjson.PreciousBlockCmd)
		hash, err := util.GetHashFromStr(c.BlockHash)
		if err != nil {
			return nil, err
		}
		blockIndex := chain.GetInstance().FindBlockIndex(*hash)
		if blockIndex == nil {
			return nil, &btcjson.RPCError{
				Code:    btcjson.ErrRPCBlockNotFound,
				Message: "Block not found",
			}
		}
		state := valistate.ValidationState{}
		chain.PreciousBlock(consensus.ActiveNetParams, &state, blockIndex)
		if !state.IsValid() {

		}*/ // todo open
	return nil, nil
}

func handleInvalidateBlock(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c, ok := cmd.(*btcjson.InvalidateBlockCmd)
	bkHash, err := util.GetHashFromStr(c.BlockHash)
	if !ok || err != nil {
		return nil, btcjson.NewRPCError(btcjson.RPCInvalidParameter, "malformed request")
	}

	persist.CsMain.Lock()
	defer persist.CsMain.Unlock()

	log.Debug("InvalidateBlock start: " + chainStatus(bkHash))

	gchain := chain.GetInstance()
	bi := gchain.FindBlockIndex(*bkHash)
	if bi == nil {
		log.Error("InvalidateBlock failed, target block not found. " + chainStatus(bkHash))
		return nil, btcjson.NewRPCError(btcjson.RPCInvalidAddressOrKey, "Block not found")
	}

	for gchain.FindHashInActive(*bkHash) != nil {
		lchain.InvalidBlockParentFound(gchain.Tip())

		if err = lchain.DisconnectTip(false); err != nil {
			log.Error("InvalidateBlock failed during DisconnectTip, " + chainStatus(bkHash))
			return nil, btcjson.NewRPCError(btcjson.RPCDatabaseError, "disconnect failed")
		}
	}

	lchain.InvalidBlockFound(bi)

	if err = lchain.ActivateBestChain(nil); err != nil {
		log.Error("InvalidateBlock failed during ActivateBestChain, " + chainStatus(bkHash))
		return nil, btcjson.NewRPCError(btcjson.RPCDatabaseError, "failed with err:"+err.Error())
	}
	lmempool.RemoveForReorg(chain.GetInstance().Tip().Height+1, int(tx.StandardLockTimeVerifyFlags))
	log.Debug("InvalidateBlock end: " + chainStatus(bkHash))
	return nil, nil
}

func handleReconsiderBlock(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	c, ok := cmd.(*btcjson.ReconsiderBlockCmd)
	bkHash, err := util.GetHashFromStr(c.BlockHash)
	if !ok || err != nil {
		return nil, btcjson.NewRPCError(btcjson.RPCInvalidParameter, "malformed request")
	}

	persist.CsMain.Lock()
	defer persist.CsMain.Unlock()

	gchain := chain.GetInstance()
	targetBI := gchain.FindBlockIndex(*bkHash)
	if targetBI == nil {
		log.Error("ReconsiderBlock failed, target block not found. " + chainStatus(bkHash))
		return nil, btcjson.NewRPCError(btcjson.RPCInvalidAddressOrKey, "Block not found")
	}

	log.Debug("ReconsiderBlock start: " + chainStatus(bkHash))
	targetBI.SubStatus(blockindex.BlockInvalidMask)
	gchain.ResetBlockFailureFlags(targetBI)

	if err = lchain.ActivateBestChain(nil); err != nil {
		log.Error("ReconsiderBlock failed, " + chainStatus(bkHash))
		return nil, btcjson.NewRPCError(btcjson.RPCDatabaseError, "failed with err:"+err.Error())
	}

	log.Debug("ReconsiderBlock end: " + chainStatus(bkHash))
	return nil, nil
}

func chainStatus(targetHash *util.Hash) string {
	gchain := chain.GetInstance()
	return fmt.Sprintf("target hash: %s, current tip: %+v", targetHash, gchain.Tip())
}

func handleWaitForNewBlock(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	return nil, nil
}

func handleWaitForBlock(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	return nil, nil
}

func handleWaitForBlockHeight(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
	//TODO notify tipchange
	c := cmd.(*btcjson.WaitForBlockHeightCmd)
	height := c.Height
	timeout := *c.Timeout

	if timeout == 0 {
		//0 indicates no timeout.
		timeout = math.MaxInt32
	}

	timeEnd := time.Now().Add(time.Duration(timeout) * time.Millisecond)
	gchain := chain.GetInstance()
	ret := &btcjson.WaitForBlockHeightResult{}

	if height <= gchain.TipHeight() {
		ret = &btcjson.WaitForBlockHeightResult{
			Hash:   gchain.Tip().GetBlockHash().String(),
			Height: gchain.TipHeight(),
		}
		return ret, nil
	}

	for {
		if height <= gchain.TipHeight() {
			ret.Hash = gchain.GetIndex(height).GetBlockHash().String()
			ret.Height = height
			return ret, nil
		}
		if time.Now().After(timeEnd) {
			if height <= gchain.TipHeight() {
				ret.Hash = gchain.GetIndex(height).GetBlockHash().String()
				ret.Height = height
				return ret, nil
			}
			ret.Hash = gchain.Tip().GetBlockHash().String()
			ret.Height = gchain.TipHeight()
			return ret, nil
		}
		time.Sleep(time.Second)
	}
}

func registerBlockchainRPCCommands() {
	for name, handler := range blockchainHandlers {
		appendCommand(name, handler)
	}
}