/**
 * Source Code first verified at https://etherscan.io on Thursday, April 4, 2019
 (UTC) */

pragma solidity ^0.5.4;

// File: node_modules/openzeppelin-solidity/contracts/token/ERC20/IERC20.sol

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
interface IERC20 {
    function transfer(address to, uint256 value) external returns (bool);

    function approve(address spender, uint256 value) external returns (bool);

    function transferFrom(address from, address to, uint256 value) external returns (bool);

    function totalSupply() external view returns (uint256);

    function balanceOf(address who) external view returns (uint256);

    function allowance(address owner, address spender) external view returns (uint256);

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: node_modules/openzeppelin-solidity/contracts/math/SafeMath.sol

/**
 * @title SafeMath
 * @dev Unsigned math operations with safety checks that revert on error
 */
library SafeMath {
    /**
    * @dev Multiplies two unsigned integers, reverts on overflow.
    */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
    * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
    */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
    * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
    * @dev Adds two unsigned integers, reverts on overflow.
    */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
    * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
    * reverts when dividing by zero.
    */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}

// File: node_modules/openzeppelin-solidity/contracts/token/ERC20/ERC20.sol

/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
 * Originally based on code by FirstBlood:
 * https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 *
 * This implementation emits additional Approval events, allowing applications to reconstruct the allowance status for
 * all accounts just by listening to said events. Note that this isn't required by the specification, and other
 * compliant implementations may not do it.
 */
contract ERC20 is IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) internal _balances;

    mapping (address => mapping (address => uint256)) private _allowed;

    uint256 private _totalSupply;

    /**
    * @dev Total number of tokens in existence
    */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param owner The address to query the balance of.
    * @return An uint256 representing the amount owned by the passed address.
    */
    function balanceOf(address owner) public view returns (uint256) {
        return _balances[owner];
    }

    /**
     * @dev Function to check the amount of tokens that an owner allowed to a spender.
     * @param owner address The address which owns the funds.
     * @param spender address The address which will spend the funds.
     * @return A uint256 specifying the amount of tokens still available for the spender.
     */
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowed[owner][spender];
    }

    /**
    * @dev Transfer token for a specified address
    * @param to The address to transfer to.
    * @param value The amount to be transferred.
    */
    function transfer(address to, uint256 value) public returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    /**
     * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
     * Beware that changing an allowance with this method brings the risk that someone may use both the old
     * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
     * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     */
    function approve(address spender, uint256 value) public returns (bool) {
        require(spender != address(0));

        _allowed[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }

    /**
     * @dev Transfer tokens from one address to another.
     * Note that while this function emits an Approval event, this is not required as per the specification,
     * and other compliant implementations may not emit the event.
     * @param from address The address which you want to send tokens from
     * @param to address The address which you want to transfer to
     * @param value uint256 the amount of tokens to be transferred
     */
    function transferFrom(address from, address to, uint256 value) public returns (bool) {
        _allowed[from][msg.sender] = _allowed[from][msg.sender].sub(value);
        _transfer(from, to, value);
        emit Approval(from, msg.sender, _allowed[from][msg.sender]);
        return true;
    }

    /**
     * @dev Increase the amount of tokens that an owner allowed to a spender.
     * approve should be called when allowed_[_spender] == 0. To increment
     * allowed value is better to use this function to avoid 2 calls (and wait until
     * the first transaction is mined)
     * From MonolithDAO Token.sol
     * Emits an Approval event.
     * @param spender The address which will spend the funds.
     * @param addedValue The amount of tokens to increase the allowance by.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        require(spender != address(0));

        _allowed[msg.sender][spender] = _allowed[msg.sender][spender].add(addedValue);
        emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
        return true;
    }

    /**
     * @dev Decrease the amount of tokens that an owner allowed to a spender.
     * approve should be called when allowed_[_spender] == 0. To decrement
     * allowed value is better to use this function to avoid 2 calls (and wait until
     * the first transaction is mined)
     * From MonolithDAO Token.sol
     * Emits an Approval event.
     * @param spender The address which will spend the funds.
     * @param subtractedValue The amount of tokens to decrease the allowance by.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        require(spender != address(0));

        _allowed[msg.sender][spender] = _allowed[msg.sender][spender].sub(subtractedValue);
        emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
        return true;
    }

    /**
    * @dev Transfer token for a specified addresses
    * @param from The address to transfer from.
    * @param to The address to transfer to.
    * @param value The amount to be transferred.
    */
    function _transfer(address from, address to, uint256 value) internal {
        require(to != address(0));

        _balances[from] = _balances[from].sub(value);
        _balances[to] = _balances[to].add(value);
        emit Transfer(from, to, value);
    }

    /**
     * @dev Internal function that mints an amount of the token and assigns it to
     * an account. This encapsulates the modification of balances such that the
     * proper events are emitted.
     * @param account The account that will receive the created tokens.
     * @param value The amount that will be created.
     */
    function _mint(address account, uint256 value) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.add(value);
        _balances[account] = _balances[account].add(value);
        emit Transfer(address(0), account, value);
    }

    /**
     * @dev Internal function that burns an amount of the token of a given
     * account.
     * @param account The account whose tokens will be burnt.
     * @param value The amount that will be burnt.
     */
    function _burn(address account, uint256 value) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.sub(value);
        _balances[account] = _balances[account].sub(value);
        emit Transfer(account, address(0), value);
    }

    /**
     * @dev Internal function that burns an amount of the token of a given
     * account, deducting from the sender's allowance for said account. Uses the
     * internal burn function.
     * Emits an Approval event (reflecting the reduced allowance).
     * @param account The account whose tokens will be burnt.
     * @param value The amount that will be burnt.
     */
    function _burnFrom(address account, uint256 value) internal {
        _allowed[account][msg.sender] = _allowed[account][msg.sender].sub(value);
        _burn(account, value);
        emit Approval(account, msg.sender, _allowed[account][msg.sender]);
    }
}

// File: contracts\MeetToken.sol

contract MeetToken is ERC20 {
    string public constant name = "MeetToken"; // solium-disable-line uppercase
    string public constant symbol = "MTT"; // solium-disable-line uppercase
    uint8 public constant decimals = 18; // solium-disable-line uppercase
    uint256 public constant initialSupply = 3000000000 * (10 ** uint256(decimals));
    
    constructor() public {
        super._mint(msg.sender, initialSupply);
        owner = msg.sender;
    }

    //ownership
    address public owner;

    event OwnershipRenounced(address indexed previousOwner);
    event OwnershipTransferred(
    address indexed previousOwner,
    address indexed newOwner
    );

    modifier onlyOwner() {
        require(msg.sender == owner, "Not owner");
        _;
    }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   * @notice Renouncing to ownership will leave the contract without an owner.
   * It will not be possible to call the functions with the `onlyOwner`
   * modifier anymore.
   */
    function renounceOwnership() public onlyOwner {
        emit OwnershipRenounced(owner);
        owner = address(0);
    }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param _newOwner The address to transfer ownership to.
   */
    function transferOwnership(address _newOwner) public onlyOwner {
        _transferOwnership(_newOwner);
    }

  /**
   * @dev Transfers control of the contract to a newOwner.
   * @param _newOwner The address to transfer ownership to.
   */
    function _transferOwnership(address _newOwner) internal {
        require(_newOwner != address(0), "Already owner");
        emit OwnershipTransferred(owner, _newOwner);
        owner = _newOwner;
    }

    //pausable
    event Pause();
    event Unpause();

    bool public paused = false;
    
    /**
    * @dev Modifier to make a function callable only when the contract is not paused.
    */
    modifier whenNotPaused() {
        require(!paused, "Paused by owner");
        _;
    }

    /**
    * @dev Modifier to make a function callable only when the contract is paused.
    */
    modifier whenPaused() {
        require(paused, "Not paused now");
        _;
    }

    /**
    * @dev called by the owner to pause, triggers stopped state
    */
    function pause() public onlyOwner whenNotPaused {
        paused = true;
        emit Pause();
    }

    /**
    * @dev called by the owner to unpause, returns to normal state
    */
    function unpause() public onlyOwner whenPaused {
        paused = false;
        emit Unpause();
    }

    //freezable
    event Frozen(address target);
    event Unfrozen(address target);

    mapping(address => bool) internal freezes;

    modifier whenNotFrozen() {
        require(!freezes[msg.sender], "Sender account is locked.");
        _;
    }

    function freeze(address _target) public onlyOwner {
        freezes[_target] = true;
        emit Frozen(_target);
    }

    function unfreeze(address _target) public onlyOwner {
        freezes[_target] = false;
        emit Unfrozen(_target);
    }

    function isFrozen(address _target) public view returns (bool) {
        return freezes[_target];
    }

    function transfer(
        address _to,
        uint256 _value
    )
      public
      whenNotFrozen
      whenNotPaused
      returns (bool)
    {
        releaseLock(msg.sender);
        return super.transfer(_to, _value);
    }

    function transferFrom(
        address _from,
        address _to,
        uint256 _value
    )
      public
      whenNotPaused
      returns (bool)
    {
        require(!freezes[_from], "From account is locked.");
        releaseLock(_from);
        return super.transferFrom(_from, _to, _value);
    }

    //mintable
    event Mint(address indexed to, uint256 amount);

    function mint(
        address _to,
        uint256 _amount
    )
      public
      onlyOwner
      returns (bool)
    {
        super._mint(_to, _amount);
        emit Mint(_to, _amount);
        return true;
    }

    //burnable
    event Burn(address indexed burner, uint256 value);

    function burn(address _who, uint256 _value) public onlyOwner {
        require(_value <= super.balanceOf(_who), "Balance is too small.");

        _burn(_who, _value);
        emit Burn(_who, _value);
    }

    //lockable
    struct LockInfo {
        uint256 releaseTime;
        uint256 balance;
    }
    mapping(address => LockInfo[]) internal lockInfo;

    event Lock(address indexed holder, uint256 value, uint256 releaseTime);
    event Unlock(address indexed holder, uint256 value);

    function balanceOf(address _holder) public view returns (uint256 balance) {
        uint256 lockedBalance = 0;
        for(uint256 i = 0; i < lockInfo[_holder].length ; i++ ) {
            lockedBalance = lockedBalance.add(lockInfo[_holder][i].balance);
        }
        return super.balanceOf(_holder).add(lockedBalance);
    }

    function releaseLock(address _holder) internal {

        for(uint256 i = 0; i < lockInfo[_holder].length ; i++ ) {
            if (lockInfo[_holder][i].releaseTime <= now) {
                _balances[_holder] = _balances[_holder].add(lockInfo[_holder][i].balance);
                emit Unlock(_holder, lockInfo[_holder][i].balance);
                lockInfo[_holder][i].balance = 0;

                if (i != lockInfo[_holder].length - 1) {
                    lockInfo[_holder][i] = lockInfo[_holder][lockInfo[_holder].length - 1];
                    i--;
                }
                lockInfo[_holder].length--;

            }
        }
    }
    function lockCount(address _holder) public view returns (uint256) {
        return lockInfo[_holder].length;
    }
    function lockState(address _holder, uint256 _idx) public view returns (uint256, uint256) {
        return (lockInfo[_holder][_idx].releaseTime, lockInfo[_holder][_idx].balance);
    }

    function lock(address _holder, uint256 _amount, uint256 _releaseTime) public onlyOwner {
        require(super.balanceOf(_holder) >= _amount, "Balance is too small.");
        _balances[_holder] = _balances[_holder].sub(_amount);
        lockInfo[_holder].push(
            LockInfo(_releaseTime, _amount)
        );
        emit Lock(_holder, _amount, _releaseTime);
    }

    function lockAfter(address _holder, uint256 _amount, uint256 _afterTime) public onlyOwner {
        require(super.balanceOf(_holder) >= _amount, "Balance is too small.");
        _balances[_holder] = _balances[_holder].sub(_amount);
        lockInfo[_holder].push(
            LockInfo(now + _afterTime, _amount)
        );
        emit Lock(_holder, _amount, now + _afterTime);
    }

    function unlock(address _holder, uint256 i) public onlyOwner {
        require(i < lockInfo[_holder].length, "No lock information.");

        _balances[_holder] = _balances[_holder].add(lockInfo[_holder][i].balance);
        emit Unlock(_holder, lockInfo[_holder][i].balance);
        lockInfo[_holder][i].balance = 0;

        if (i != lockInfo[_holder].length - 1) {
            lockInfo[_holder][i] = lockInfo[_holder][lockInfo[_holder].length - 1];
        }
        lockInfo[_holder].length--;
    }

    function transferWithLock(address _to, uint256 _value, uint256 _releaseTime) public onlyOwner returns (bool) {
        require(_to != address(0), "wrong address");
        require(_value <= super.balanceOf(owner), "Not enough balance");

        _balances[owner] = _balances[owner].sub(_value);
        lockInfo[_to].push(
            LockInfo(_releaseTime, _value)
        );
        emit Transfer(owner, _to, _value);
        emit Lock(_to, _value, _releaseTime);

        return true;
    }

    function transferWithLockAfter(address _to, uint256 _value, uint256 _afterTime) public onlyOwner returns (bool) {
        require(_to != address(0), "wrong address");
        require(_value <= super.balanceOf(owner), "Not enough balance");

        _balances[owner] = _balances[owner].sub(_value);
        lockInfo[_to].push(
            LockInfo(now + _afterTime, _value)
        );
        emit Transfer(owner, _to, _value);
        emit Lock(_to, _value, now + _afterTime);

        return true;
    }

    function currentTime() public view returns (uint256) {
        return now;
    }

    function afterTime(uint256 _value) public view returns (uint256) {
        return now + _value;
    }
}