pragma solidity ^0.4.24;


/**
* @title SafeMath
* @dev Math operations with safety checks that throw on error
*/

library SafeMath {
/**
* @dev Multiplies two numbers, throws on overflow.
*/

    function mul(uint256 _a, uint256 _b) internal pure returns (uint256) {
    if (_a == 0) {
    return 0;
    }
    uint256 c = _a * _b;
    assert(c / _a == _b);
    return c;
    }
    
    
    /**
    * @dev Integer division of two numbers, truncating the quotient.
    */
    function div(uint256 _a, uint256 _b) internal pure returns (uint256) {
    // assert(_b > 0); // Solidity automatically throws when dividing by 0
    uint256 c = _a / _b;
    // assert(_a == _b * c + _a % _b); // There is no case in which this doesn't hold
    return c;
    }
    
     
    
    /**
    * @dev Substracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 _a, uint256 _b) internal pure returns (uint256) {
    assert(_b <= _a);
    return _a - _b;
    }
    
    /**
    * @dev Adds two numbers, throws on overflow.
    */
    function add(uint256 _a, uint256 _b) internal pure returns (uint256) {
    uint256 c = _a + _b;
    assert(c >= _a);
    return c;
    }
}

 

contract Ownable {
    address public owner;
    address public newOwner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor() public {
    owner = msg.sender;
    newOwner = address(0);
    }

    modifier onlyOwner() {
    require(msg.sender == owner);
    _;
    }

    modifier onlyNewOwner() {
    require(msg.sender != address(0));
    require(msg.sender == newOwner);
    _;
    }

    function transferOwnership(address _newOwner) public onlyOwner {
    require(_newOwner != address(0));
    newOwner = _newOwner;
    }
    
    function acceptOwnership() public onlyNewOwner returns(bool) {
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
    }
}


contract Pausable is Ownable {
    event Pause();
    event Unpause();
    bool public paused = false;
    
    modifier whenNotPaused() {
    require(!paused);
    _;
    }
    modifier whenPaused() {
    require(paused);
    _;
    }

    
    function pause() onlyOwner whenNotPaused public {
    paused = true;
    emit Pause();
    }
    
    
    function unpause() onlyOwner whenPaused public {
    paused = false;
    emit Unpause();
    }

}

 

contract ERC20 {
    function totalSupply() public view returns (uint256);
    function balanceOf(address who) public view returns (uint256);
    function allowance(address owner, address spender) public view returns (uint256);
    function transfer(address to, uint256 value) public returns (bool);
    function transferFrom(address from, address to, uint256 value) public returns (bool);
    function approve(address spender, uint256 value) public returns (bool);
    event Approval(address indexed owner, address indexed spender, uint256 value);
    event Transfer(address indexed from, address indexed to, uint256 value);
}

 

interface TokenRecipient {
 function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external;
}

 

contract DooDooCoin is ERC20, Ownable, Pausable {
    uint128 internal MONTH = 30 * 24 * 3600; // 1 month
    using SafeMath for uint256;
    
    
    struct LockupInfo {
    uint256 releaseTime;
    uint256 termOfRound;
    uint256 unlockAmountPerRound;
    uint256 lockupBalance;
    }
    
    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 internal initialSupply;
    uint256 internal totalSupply_;
    
    mapping(address => uint256) internal balances;
    mapping(address => bool) internal locks;
    mapping(address => bool) public frozen;
    mapping(address => mapping(address => uint256)) internal allowed;
    mapping(address => LockupInfo) internal lockupInfo;
    
    event Unlock(address indexed holder, uint256 value);
    event Lock(address indexed holder, uint256 value);
    event Burn(address indexed owner, uint256 value);
    event Mint(uint256 value);
    event Freeze(address indexed holder);
    event Unfreeze(address indexed holder);
    
    modifier notFrozen(address _holder) {
    require(!frozen[_holder]);
    _;
    }

    constructor() public {
    name = "DooDooCoin";
    symbol = "DDC";
    decimals = 0;
    initialSupply = 10000000;
    totalSupply_ = 10000000;
    balances[owner] = totalSupply_;
    emit Transfer(address(0), owner, totalSupply_);
    }

    function () public payable {
    revert();
    }

    function totalSupply() public view returns (uint256) {
    return totalSupply_;
    }

 

/**
     * 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 != address(0));
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);
    
       balances[_from] = balances[_from].sub(_value);
       balances[_to] = balances[_to].add(_value);
      allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
      emit Transfer(_from, _to, _value);
    }
    
    function transfer(address _to, uint256 _value) public whenNotPaused notFrozen(msg.sender) returns (bool) {
    
    if (locks[msg.sender]) {
    autoUnlock(msg.sender);
    }
    
    require(_to != address(0));
    require(_value <= balances[msg.sender]);
    
    // SafeMath.sub will throw if there is not enough balance.
    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit Transfer(msg.sender, _to, _value);
    return true;
    }


    function balanceOf(address _holder) public view returns (uint256 balance) {
    return balances[_holder] + lockupInfo[_holder].lockupBalance;
    }
    
    function send (address _from, address _to, uint256 _value) public whenNotPaused notFrozen(_from) returns (bool) {
        if(locks[_from]){
            autoUnlock(_from);
        }
        require(_to != address(0));
        require(_value <= balances[_from]);
        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        emit Transfer(_from, _to, _value);
    }
     
    function transferFrom(address _from, address _to, uint256 _value) public whenNotPaused notFrozen(_from)returns (bool) {

        if (locks[_from]) {
        autoUnlock(_from);
        }
    
    require(_to != address(0));
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);

    _transfer(_from, _to, _value);
    
    return true;
    }
    
    

    function approve(address _spender, uint256 _value) public whenNotPaused returns (bool) {
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
    }
    
    function approveAndCall(address _spender, uint256 _value, bytes _extraData) public returns (bool success) {
    require(isContract(_spender));
    TokenRecipient spender = TokenRecipient(_spender);
    
        if (approve(_spender, _value)) {
        spender.receiveApproval(msg.sender, _value, this, _extraData);
        return true;
        }
    
    }

 

    function allowance(address _holder, address _spender) public view returns (uint256) {
    return allowed[_holder][_spender];
    }

 

    function lock(address _holder, uint256 _amount, uint256 _releaseStart, uint256 _termOfRound, uint256 _releaseRate) public onlyOwner returns (bool) {
    require(locks[_holder] == false);
    require(balances[_holder] >= _amount);
    balances[_holder] = balances[_holder].sub(_amount);
    lockupInfo[_holder] = LockupInfo(_releaseStart, _termOfRound, _amount.div(100).mul(_releaseRate), _amount);
    
    locks[_holder] = true;
    emit Lock(_holder, _amount);
    return true;
    }

 

    function unlock(address _holder) public onlyOwner returns (bool) {
    require(locks[_holder] == true);
    uint256 releaseAmount = lockupInfo[_holder].lockupBalance;
    
    delete lockupInfo[_holder];
    locks[_holder] = false;
    emit Unlock(_holder, releaseAmount);
    balances[_holder] = balances[_holder].add(releaseAmount);
    return true;
    
    }

 
    function freezeAccount(address _holder) public onlyOwner returns (bool) {
    require(!frozen[_holder]);
    frozen[_holder] = true;
    emit Freeze(_holder);
    return true;
    }

 

    function unfreezeAccount(address _holder) public onlyOwner returns (bool) {
    require(frozen[_holder]);
    frozen[_holder] = false;
    emit Unfreeze(_holder);
    return true;
    }

 

    function getNowTime() public view returns(uint256) {
    return now;
    }


    function showLockState(address _holder) public view returns (bool, uint256, uint256, uint256, uint256) {
    return (locks[_holder], lockupInfo[_holder].lockupBalance, lockupInfo[_holder].releaseTime, lockupInfo[_holder].termOfRound, lockupInfo[_holder].unlockAmountPerRound);
    }
    
    
   function burn(uint256 _value) public onlyOwner returns (bool success) {
    require(_value <= balances[msg.sender]);
    address burner = msg.sender;
    balances[burner] = balances[burner].sub(_value);
    totalSupply_ = totalSupply_.sub(_value);
    emit Burn(burner, _value);
    return true;
    }

 
    function mint( uint256 _amount) onlyOwner public returns (bool) {
    totalSupply_ = totalSupply_.add(_amount);
    balances[owner] = balances[owner].add(_amount);
    
    emit Transfer(address(0), owner, _amount);
    return true;
    }

    function isContract(address addr) internal view returns (bool) {
    uint size;
    assembly{size := extcodesize(addr)}
    return size > 0;
    }

    function autoUnlock(address _holder) internal returns (bool) {
        if (lockupInfo[_holder].releaseTime <= now) {
        return releaseTimeLock(_holder);
        }
    
    return false;
    }


    function releaseTimeLock(address _holder) internal returns(bool) {
    require(locks[_holder]);
    uint256 releaseAmount = 0;
    
     
    // If lock status of holder is finished, delete lockup info.
    for( ; lockupInfo[_holder].releaseTime <= now ; )
    {
    if (lockupInfo[_holder].lockupBalance <= lockupInfo[_holder].unlockAmountPerRound) {
    releaseAmount = releaseAmount.add(lockupInfo[_holder].lockupBalance);
    delete lockupInfo[_holder];
    locks[_holder] = false;
    break;
    } else {
    releaseAmount = releaseAmount.add(lockupInfo[_holder].unlockAmountPerRound);
    lockupInfo[_holder].lockupBalance = lockupInfo[_holder].lockupBalance.sub(lockupInfo[_holder].unlockAmountPerRound);
    lockupInfo[_holder].releaseTime = lockupInfo[_holder].releaseTime.add(lockupInfo[_holder].termOfRound);
    }
    
    }
    
    emit Unlock(_holder, releaseAmount);
    balances[_holder] = balances[_holder].add(releaseAmount);
    return true;
    }
}