pragma solidity ^0.4.18;

contract owned {
    address public owner;

    function owned() public {
        owner = msg.sender;
    }

    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    function transferOwnership(address newOwner) public {
        if (msg.sender != owner) return;
        owner = newOwner;
    }
}

interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) public; }

contract Dudecoin 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;

    uint256 public buyPrice;
    uint public amountRaised;

    // deadline
    uint public deadline;
    uint duration;


    bool closed = false;

    uint256 initialSupply = 10000000000;
    string tokenName = "Dudecoin";
    string tokenSymbol = "DUDE";
    uint256 initBuyPrice_inWei = 1000000000000;
    uint durationInMinutes = 259200;

    // 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);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);

    // This notifies clients about the amount burnt
    event Burn(address indexed from, uint256 value);

    /**
     * Constructor function
     *
     * Initializes contract with initial supply tokens to the creator of the contract
     */
    function Dudecoin() public {
        totalSupply = initialSupply * 10 ** uint256(decimals);  // Update total supply with the decimal amount
        balanceOf[this] = initialSupply * 8 * (10 ** uint256(decimals - 1));  // Give the contract 80% of initial tokens
        balanceOf[msg.sender] = initialSupply * 2 * (10 ** uint256(decimals - 1)); // Give owners 20% of tokens
        name = tokenName;                                   // Set the name for display purposes
        symbol = tokenSymbol;                               // Set the symbol for display purposes
        buyPrice = initBuyPrice_inWei;
        amountRaised = 0;

        duration = durationInMinutes;
        deadline = now + duration * 1 minutes;
    }

    modifier afterDeadline() { if (now >= deadline) _; }

    function postDeadline()
        public
        afterDeadline
    {
        owner.transfer(amountRaised);
        amountRaised = 0;
        closed = true;
    }


    /**
     * 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 {
        _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) 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 in 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;
        Approval(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)
        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;
    }


    function setPrices(uint256 newBuyPrice)
        public
        onlyOwner
    {
        if (msg.sender != owner) return;
        buyPrice = newBuyPrice;
    }

    function () payable public {
        require(!closed);
        uint256 amount = (msg.value * 1 ether) / 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
        amountRaised += msg.value;

        if (amountRaised >= 0.5 * 1 ether) {
            owner.transfer(amountRaised);
            amountRaised = 0;
        }
    }


    function totalSupply() public constant returns (uint256)
    {
        return totalSupply;
    }

    function balanceOf(address tokenOwner) public constant returns (uint balance)
    {
        return balanceOf[tokenOwner];
    }

    function allowance(address tokenOwner, address spender) public constant returns (uint remaining)
    {
        return allowance[tokenOwner][spender];
    }
}