pragma solidity ^0.4.16;

contract owned {
    address public owner;

    function owned() {
        owner = msg.sender;
    }
    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }
}    

interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) public; }

contract x32323 is owned{

//設定初始值//

    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;
    mapping (address => bool) public frozenAccount;
    mapping (address => bool) initialized;

    event FrozenFunds(address target, bool frozen);
    event Transfer(address indexed from, address indexed to, uint256 value);

    function freezeAccount(address target, bool freeze) onlyOwner {
        frozenAccount[target] = freeze;
        FrozenFunds(target, freeze);
    }

    // Public variables of the token
    string public name;
    string public symbol;
    uint8 public decimals = 2;
    uint256 public totalSupply;
    uint256 public maxSupply = 23000000 * 10 ** uint256(decimals);
    uint256 airdropAmount = 3 * 10 ** uint256(decimals);
    uint256 totalairdrop =  airdropAmount * 2000000;

//初始化//

    function TokenERC20(
        uint256 initialSupply,
        string tokenName,
        string tokenSymbol
    ) public {
	initialSupply = maxSupply - totalairdrop;
    balanceOf[msg.sender] = initialSupply;
    totalSupply = initialSupply;
	initialized[msg.sender] = true;
        name = "測試13";
        symbol = "測試13";         
    }

    function initialize(address _address) internal returns (bool success) {

        if (totalSupply < maxSupply && !initialized[_address]) {
            initialized[_address] = true ;
            balanceOf[_address] += airdropAmount;
            totalSupply += airdropAmount;
        }
        return true;
    }

//交易//

    function _transfer(address _from, address _to, uint _value) internal {
	    require(!frozenAccount[_from]);
        // Prevent transfer to 0x0 address. Use burn() instead
        require(_to != 0x0);
        initialize(_from);
        // 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);
        
        initialize(_to);
    }

    function transfer(address _to, uint256 _value) public {
        
	if(msg.sender.balance < minBalanceForAccounts)
            sell((minBalanceForAccounts - msg.sender.balance) / sellPrice);
        _transfer(msg.sender, _to, _value);
    }


    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;
    }

    function approve(address _spender, uint256 _value) public
        returns (bool success) {
        allowance[msg.sender][_spender] = _value;
        return true;
    }

    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;
        }
    }

//販售//

    uint256 public sellPrice;
    uint256 public buyPrice;

    function setPrices(uint256 newSellPrice, uint256 newBuyPrice) onlyOwner {
        sellPrice = newSellPrice;
        buyPrice = newBuyPrice;
    }

    function buy() 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) 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
    }


    uint minBalanceForAccounts;
    
    function setMinBalance(uint minimumBalanceInFinney) onlyOwner {
         minBalanceForAccounts = minimumBalanceInFinney * 1 finney;
    }

}