pragma solidity ^0.4.11;

interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData); }

contract owned {
    address public owner;

    function owned() {
        owner = msg.sender;
    }

    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    function transferOwnership(address _newOwner) onlyOwner {
        owner = _newOwner;
    }
}

contract PopeCoin is owned {
    // Public variables of the token
    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 public totalSupply;

    // This creates an array with all balances
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;

    // This generates a public event on the blockchain that will notify clients
    event Transfer(address indexed from, address indexed to, uint256 value);

    // This notifies clients about the amount burnt
    event Burn(address indexed from, uint256 value);

    /**
     * Constrctor function
     *require
     * Initializes contract with initial supply tokens to the creator of the contract
     */
    function PopeCoin(
        uint256 initialSupply,
        string tokenName,
        uint8 decimalUnits,
        string tokenSymbol,
        address centralMinter
    ) {
        balanceOf[msg.sender] = initialSupply;              // Give the creator all initial tokens
        totalSupply = initialSupply;                        // Update total supply
        name = tokenName;                                   // Set the name for display purposes
        symbol = tokenSymbol;                               // Set the symbol for display purposes
        decimals = decimalUnits;                            // Amount of decimals for display purposes
        
        if (centralMinter != 0x00) {
            owner = centralMinter;
        }
    }

    /**
     * Internal transfer, only can be called by this contract
     */
    function _transfer(address _from, address _to, uint _value) internal {
        require(_to != 0x0);                               // Prevent transfer to 0x0 address. Use burn() instead
        require(balanceOf[_from] >= _value);                // Check if the sender has enough
        require(balanceOf[_to] + _value > balanceOf[_to]); // Check for overflows
        
        balanceOf[_from] -= _value;                         // Subtract from the sender
        balanceOf[_to] += _value;                           // Add the same to the recipient
        
        // Notify
        Transfer(_from, _to, _value);
    }

    /**
     * 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) {
        _transfer(msg.sender, _to, _value);
    }

    /**
     * Transfer tokens from other address
     *
     * Send `_value` tokens to `_to` in 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) 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 in your behalf
     *
     * @param _spender The address authorized to spend
     * @param _value the max amount they can spend
     */
    function approve(address _spender, uint256 _value)
        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 in 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)
        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) 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
        
        // Notify
        Burn(msg.sender, _value);
        
        return true;
    }

    /**
     * Destroy tokens from other ccount
     *
     * 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) 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
        
        // Notify
        Burn(_from, _value);
        
        return true;
    }
    
    /**
     * Creates more tokens
     * 
     * @param _to the address ofwho will get newly minted tokens
     * @param _value the amount of money to create
     */
    function mintToken(address _to, uint256 _value) onlyOwner {
        require(totalSupply + _value > totalSupply); // Check for overflows
        
        balanceOf[_to] += _value;
        totalSupply += _value;
        
        // Notify 
        Transfer(0, owner, _value);
        
        if (owner != _to) {
            Transfer(owner, _to, _value);
        }
    }
}