pragma solidity ^0.4.18;

// ----------------------------------------------------------------------------
// Safe maths
// ----------------------------------------------------------------------------
library SafeMath {
    function add(uint a, uint b) internal pure returns (uint c) {
        c = a + b;
        require(c >= a);
    }
    function sub(uint a, uint b) internal pure returns (uint c) {
        require(b <= a);
        c = a - b;
    }
    function mul(uint a, uint b) internal pure returns (uint c) {
        c = a * b;
        require(a == 0 || c / a == b);
    }
    function div(uint a, uint b) internal pure returns (uint c) {
        require(b > 0);
        c = a / b;
    }
}


// ----------------------------------------------------------------------------
// ERC Token Standard #20 Interface
// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md
// ----------------------------------------------------------------------------
contract ERC20Interface {
    function totalSupply() public constant returns (uint);
    function balanceOf(address tokenOwner) public constant returns (uint balance);
    function allowance(address tokenOwner, address spender) public constant returns (uint remaining);
    function transfer(address to, uint tokens) public returns (bool success);
    function approve(address spender, uint tokens) public returns (bool success);
    function transferFrom(address from, address to, uint tokens) public returns (bool success);

    event Transfer(address indexed from, address indexed to, uint tokens);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}

// ----------------------------------------------------------------------------
// Owned contract
// ----------------------------------------------------------------------------
contract Owned {
    address public owner;
    address public newOwner;

    event OwnershipTransferred(address indexed _from, address indexed _to);

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

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

    function transferOwnership(address _newOwner) public onlyOwner {
        newOwner = _newOwner;
    }
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        OwnershipTransferred(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}

// 低碳未来Token
// Symbol      : LCT
// Name        : Lowcarbon Token
// Total supply: 1000000000   初始发行10亿，最大不超过110亿，剩余100亿通过增加接口增发（挖矿）。
// Decimals    : 1  1位小数位
// ----------------------------------------------------------------------------
contract LowcarbonToken is ERC20Interface, Owned {
    using SafeMath for uint;

    string public symbol;
    string public  name;
    uint8 public decimals;
    uint public _totalSupply; //总供应量
    uint public hourlyProduction; //每小时产量
    uint public accumulatedHours; //累计小时数
    uint public last_mint; //上次挖矿时间

    mapping(address => uint) balances;
    mapping(address => mapping(address => uint)) allowed;

    event Mint(address indexed to, uint256 amount);

    // ------------------------------------------------------------------------
    // Constructor
    // ------------------------------------------------------------------------
    function LowcarbonToken() public {
        symbol = "LCT";
        name = "Low Carbon Token";
        decimals = 1;
        last_mint = 0;
        hourlyProduction = 114155; //放大10倍值
        accumulatedHours = 0;
        _totalSupply = 1000000000 * 10**uint(decimals); //初始发行
        balances[owner] = _totalSupply;
        Transfer(address(0), owner, _totalSupply);
    }


    // ------------------------------------------------------------------------
    // Total supply
    // ------------------------------------------------------------------------
    function totalSupply() public constant returns (uint) {
        return _totalSupply  - balances[address(0)];
    }


    // ------------------------------------------------------------------------
    // Get the token balance for account `tokenOwner`
    // ------------------------------------------------------------------------
    function balanceOf(address tokenOwner) public constant returns (uint balance) {
        return balances[tokenOwner];
    }


    // ------------------------------------------------------------------------
    // Transfer the balance from token owner's account to `to` account
    // - Owner's account must have sufficient balance to transfer
    // - 0 value transfers are allowed
    // ------------------------------------------------------------------------
    function transfer(address to, uint tokens) public returns (bool success) {
        balances[msg.sender] = balances[msg.sender].sub(tokens);
        balances[to] = balances[to].add(tokens);
        Transfer(msg.sender, to, tokens);
        return true;
    }


    // ------------------------------------------------------------------------
    // Token owner can approve for `spender` to transferFrom(...) `tokens`
    // from the token owner's account
    //
    // https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md
    // recommends that there are no checks for the approval double-spend attack
    // as this should be implemented in user interfaces 
    // ------------------------------------------------------------------------
    function approve(address spender, uint tokens) public returns (bool success) {
        allowed[msg.sender][spender] = tokens;
        Approval(msg.sender, spender, tokens);
        return true;
    }


    // ------------------------------------------------------------------------
    // Transfer `tokens` from the `from` account to the `to` account
    // 
    // The calling account must already have sufficient tokens approve(...)-d
    // for spending from the `from` account and
    // - From account must have sufficient balance to transfer
    // - Spender must have sufficient allowance to transfer
    // - 0 value transfers are allowed
    // ------------------------------------------------------------------------
    function transferFrom(address from, address to, uint tokens) public returns (bool success) {
        balances[from] = balances[from].sub(tokens);
        allowed[from][msg.sender] = allowed[from][msg.sender].sub(tokens);
        balances[to] = balances[to].add(tokens);
        Transfer(from, to, tokens);
        return true;
    }


    // ------------------------------------------------------------------------
    // Returns the amount of tokens approved by the owner that can be
    // transferred to the spender's account
    // ------------------------------------------------------------------------
    function allowance(address tokenOwner, address spender) public constant returns (uint remaining) {
        return allowed[tokenOwner][spender];
    }

    // ------------------------------------------------------------------------
    // Don't accept ETH
    // ------------------------------------------------------------------------
    function () public payable {
        revert();
    }

    // ------------------------------------------------------------------------
    // Owner can transfer out any accidentally sent ERC20 tokens
    // ------------------------------------------------------------------------
    function transferAnyERC20Token(address tokenAddress, uint tokens) public onlyOwner returns (bool success) {
        return ERC20Interface(tokenAddress).transfer(owner, tokens);
    }

    /**
   * @dev Function to mint tokens
   * @return A boolean that indicates if the operation was successful.
   */
    function mint() onlyOwner public returns (bool) {
        if(last_mint == 0){  //首次调用，不挖矿
            last_mint = now;
            return true;
        }

        if(hourlyProduction < 1){
            revert(); //每小时产值小0.1不能再发行
        }
        uint diffHours = (now - last_mint)/3600; //计算小时数
        if(diffHours == 0){
            revert(); //小于1小时不能挖矿
        }
        
        uint _amount;
        if((accumulatedHours + diffHours) > 8760 ){
            _amount = hourlyProduction * (8760 - accumulatedHours);  //调整前部分产值计算
            hourlyProduction = hourlyProduction*9/10; //调整生产率
            accumulatedHours = accumulatedHours + diffHours - 8760; //初始化累计值
            _amount += hourlyProduction*accumulatedHours;  //调整后部分产值计算
        }
        else{
            _amount = hourlyProduction * diffHours;
            accumulatedHours += diffHours; //增加累计小时数
        }
        _totalSupply = _totalSupply.add(_amount);
        balances[owner] = balances[owner].add(_amount);
        last_mint = now;
        Mint(owner, _amount);
        return true;
    }
}