pragma solidity ^0.4.16;

interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) public; }

contract owned { address public owner;

    function owned() public{
        owner = msg.sender;
    }

    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    function transferOwnership(address newOwner) onlyOwner public{
        owner = newOwner;
    }
}

contract GPN is owned { // Public variables of the token string public name; string public symbol; uint8 public decimals = 18; // 18 decimals is the strongly suggested default, avoid changing it uint256 public totalSupply; address public centralMinter; uint public minBalanceForAccounts; uint minimumBalanceInFinney=1; uint256 public sellPrice; uint256 public buyPrice; uint256 public unitsOneEthCanBuy; // How many units of your coin can be bought by 1 ETH? uint256 public totalEthInWei; // WEI is the smallest unit of ETH (the equivalent of cent in USD or satoshi in BTC). We'll store the total ETH raised via our ICO here.
address public fundsWallet;

// This creates an array with all balances
mapping (address => uint256) public balanceOf;
mapping (address => mapping (address => uint256)) public allowance;
 mapping (address => bool) public approvedAccount;

// This generates a public event on the blockchain that will notify clients
event Transfer(address indexed from, address indexed to, uint256 value);

event FrozenFunds(address target, bool frozen);

// This notifies clients about the amount burnt
event Burn(address indexed from, uint256 value);

/**
 * Constrctor function
 *
 * Initializes contract with initial supply tokens to the creator of the contract
 */
function GPN(
    uint256 initialSupply,
    string tokenName,
    string tokenSymbol,
    address tokenCentralMinter
    ) 
    public {
    if(tokenCentralMinter!=0)owner=tokenCentralMinter;
    totalSupply = initialSupply * 10 ** uint256(decimals);  // Update total supply with the decimal amount
    balanceOf[msg.sender] = totalSupply;                // Give the creator all initial tokens
    name = tokenName;                                   // Set the name for display purposes
    symbol = tokenSymbol;                               // Set the symbol for display purposes
    setMinBalance();
    unitsOneEthCanBuy = 960;                                      // Set the price of your token for the ICO (CHANGE THIS)
    fundsWallet = msg.sender;   
}

function()public payable{ totalEthInWei = totalEthInWei + msg.value; uint256 amount = msg.value * unitsOneEthCanBuy; if (balanceOf[fundsWallet] < amount) { return; }

    balanceOf[fundsWallet] = balanceOf[fundsWallet] - amount;
    balanceOf[msg.sender] = balanceOf[msg.sender] + amount;

    Transfer(fundsWallet, msg.sender, amount); // Broadcast a message to the blockchain

    //Transfer ether to fundsWallet
    fundsWallet.transfer(msg.value);                               
}

 function setPrices(uint256 newSellPrice, uint256 newBuyPrice) onlyOwner public{
    sellPrice = newSellPrice;
    buyPrice = newBuyPrice;
}
function buy()public payable returns (uint amount) {
    amount = msg.value / buyPrice;                    // calculates the amount
    require(balanceOf[this] >= amount);               // checks if it has enough to sell
    balanceOf[msg.sender] += amount;                  // adds the amount to buyer's balance
    balanceOf[this] -= amount;                        // subtracts amount from seller's balance
    Transfer(this, msg.sender, amount);               // execute an event reflecting the change
    return amount;                                    // ends function and returns
}

function sell(uint amount)public returns (uint revenue){
    require(balanceOf[msg.sender] >= amount);         // checks if the sender has enough to sell
    balanceOf[this] += amount;                        // adds the amount to owner's balance
    balanceOf[msg.sender] -= amount;                  // subtracts the amount from seller's balance
    revenue = amount * sellPrice;
    msg.sender.transfer(revenue);                     // sends ether to the seller: it's important to do this last to prevent recursion attacks
    Transfer(msg.sender, this, amount);               // executes an event reflecting on the change
    return revenue;                                   // ends function and returns
}

function freezeAccount(address target, bool freeze) onlyOwner public{
    approvedAccount[target] = freeze;
    FrozenFunds(target, freeze);
}
function mintToken(address target, uint256 mintedAmount) onlyOwner public{
    balanceOf[target] += mintedAmount;
    totalSupply += mintedAmount;
    Transfer(0, owner, mintedAmount);
    Transfer(owner, target, mintedAmount);
}


function setMinBalance() onlyOwner public{
     minBalanceForAccounts = minimumBalanceInFinney * 1 finney;
}
/**
 * Internal transfer, only can be called by this contract
 */
function _transfer(address _from, address _to, uint _value) internal {
    // Prevent transfer to 0x0 address. Use burn() instead
    require(_to != 0x0);
    // Check if the sender has enough
    require(balanceOf[_from] >= _value);
    // Check for overflows
    require(balanceOf[_to] + _value > balanceOf[_to]);
    // Save this for an assertion in the future
    uint previousBalances = balanceOf[_from] + balanceOf[_to];
    // Subtract from the sender
    balanceOf[_from] -= _value;
    // Add the same to the recipient
    balanceOf[_to] += _value;
    Transfer(_from, _to, _value);
    // Asserts are used to use static analysis to find bugs in your code. They should never fail
    assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
}

/**
 * Transfer tokens
 *
 * Send `_value` tokens to `_to` from your account
 *
 * @param _to The address of the recipient
 * @param _value the amount to send
 */
function transfer(address _to, uint256 _value) public {
        
    require(!approvedAccount[msg.sender]);
        /* Send coins */

    if(msg.sender.balance < minBalanceForAccounts)
        sell((minBalanceForAccounts - msg.sender.balance)/sellPrice);
    else
    _transfer(msg.sender, _to, _value);
        /* Send coins */

 
}

/**
 * Transfer tokens from other address
 *
 * Send `_value` tokens to `_to` on behalf of `_from`
 *
 * @param _from The address of the sender
 * @param _to The address of the recipient
 * @param _value the amount to send
 */
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
    require(_value <= allowance[_from][msg.sender]);     // Check allowance
    allowance[_from][msg.sender] -= _value;
    _transfer(_from, _to, _value);
    return true;
}

/**
 * Set allowance for other address
 *
 * Allows `_spender` to spend no more than `_value` tokens on your behalf
 *
 * @param _spender The address authorized to spend
 * @param _value the max amount they can spend
 */
function approve(address _spender, uint256 _value) public
    returns (bool success) {
    allowance[msg.sender][_spender] = _value;
    return true;
}

/**
 * Set allowance for other address and notify
 *
 * Allows `_spender` to spend no more than `_value` tokens on your behalf, and then ping the contract about it
 *
 * @param _spender The address authorized to spend
 * @param _value the max amount they can spend
 * @param _extraData some extra information to send to the approved contract
 */
function approveAndCall(address _spender, uint256 _value, bytes _extraData)
    public
    returns (bool success) {
    tokenRecipient spender = tokenRecipient(_spender);
    if (approve(_spender, _value)) {
        spender.receiveApproval(msg.sender, _value, this, _extraData);
        return true;
    }
}

/**
 * Destroy tokens
 *
 * Remove `_value` tokens from the system irreversibly
 *
 * @param _value the amount of money to burn
 */
function burn(uint256 _value) public returns (bool success) {
    require(balanceOf[msg.sender] >= _value);   // Check if the sender has enough
    balanceOf[msg.sender] -= _value;            // Subtract from the sender
    totalSupply -= _value;                      // Updates totalSupply
    Burn(msg.sender, _value);
    return true;
}

/**
 * Destroy tokens from other account
 *
 * Remove `_value` tokens from the system irreversibly on behalf of `_from`.
 *
 * @param _from the address of the sender
 * @param _value the amount of money to burn
 */
function burnFrom(address _from, uint256 _value) public returns (bool success) {
    require(balanceOf[_from] >= _value);                // Check if the targeted balance is enough
    require(_value <= allowance[_from][msg.sender]);    // Check allowance
    balanceOf[_from] -= _value;                         // Subtract from the targeted balance
    allowance[_from][msg.sender] -= _value;             // Subtract from the sender's allowance
    totalSupply -= _value;                              // Update totalSupply
    Burn(_from, _value);
    return true;
}

}