pragma solidity ^0.5.0;


library SafeMath {
    
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        uint256 c = a - b;

        return c;
    }

    
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        
        
        
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        
        require(b > 0, "SafeMath: division by zero");
        uint256 c = a / b;
        

        return c;
    }

    
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, "SafeMath: modulo by zero");
        return a % b;
    }
}

contract Ownable {
    address private _owner;

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

    
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    
    function owner() public view returns (address) {
        return _owner;
    }

    
    modifier onlyOwner() {
        require(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

interface IERC20 {
    
    function totalSupply() external view returns (uint256);

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

    
    function transfer(address recipient, uint256 amount) external returns (bool);

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

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

    
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

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

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

contract ERC20 is IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

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

    uint256 private _totalSupply;

    
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    
    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    
    function transfer(address recipient, uint256 amount) public returns (bool) {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowances[owner][spender];
    }

    
    function approve(address spender, uint256 value) public returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    
    function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, msg.sender, _allowances[sender][msg.sender].sub(amount));
        return true;
    }

    
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _approve(msg.sender, spender, _allowances[msg.sender][spender].add(addedValue));
        return true;
    }

    
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        _approve(msg.sender, spender, _allowances[msg.sender][spender].sub(subtractedValue));
        return true;
    }

    
    function _transfer(address sender, address recipient, uint256 amount) internal {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _balances[sender] = _balances[sender].sub(amount);
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    
    function _mint(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: mint to the zero address");

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

     
    function _burn(address account, uint256 value) internal {
        require(account != address(0), "ERC20: burn from the zero address");

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

    
    function _approve(address owner, address spender, uint256 value) internal {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    
    function _burnFrom(address account, uint256 amount) internal {
        _burn(account, amount);
        _approve(account, msg.sender, _allowances[account][msg.sender].sub(amount));
    }
}

library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    
    function add(Role storage role, address account) internal {
        require(!has(role, account), "Roles: account already has role");
        role.bearer[account] = true;
    }

    
    function remove(Role storage role, address account) internal {
        require(has(role, account), "Roles: account does not have role");
        role.bearer[account] = false;
    }

    
    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0), "Roles: account is the zero address");
        return role.bearer[account];
    }
}

contract MinterRole {
    using Roles for Roles.Role;

    event MinterAdded(address indexed account);
    event MinterRemoved(address indexed account);

    Roles.Role private _minters;

    constructor () internal {
        _addMinter(msg.sender);
    }

    modifier onlyMinter() {
        require(isMinter(msg.sender), "MinterRole: caller does not have the Minter role");
        _;
    }

    function isMinter(address account) public view returns (bool) {
        return _minters.has(account);
    }

    function addMinter(address account) public onlyMinter {
        _addMinter(account);
    }

    function renounceMinter() public {
        _removeMinter(msg.sender);
    }

    function _addMinter(address account) internal {
        _minters.add(account);
        emit MinterAdded(account);
    }

    function _removeMinter(address account) internal {
        _minters.remove(account);
        emit MinterRemoved(account);
    }
}

contract ERC20Mintable is ERC20, MinterRole {
    
    function mint(address account, uint256 amount) public onlyMinter returns (bool) {
        _mint(account, amount);
        return true;
    }
}

contract KRTDistribution is Ownable {
    using SafeMath for uint256;
    uint256 private constant decimalFactor = 10**uint256(18);
    uint256 public grandTotalClaimed = 0;
    uint256 public startTime;
    address public token_address;

    enum AllocationType {AIRDROP}

    
    struct Allocation {
        uint8 AllocationType; 
        uint256 allocation;  
        bool delivered;
    }
    
    mapping (address => Allocation) public allocations;

    
    mapping (address => bool) public airdropAdmins;

    
    mapping (address => bool) public airdrops;

    modifier onlyOwnerOrAdmin() {
        require(msg.sender == owner() || airdropAdmins[msg.sender]);
        _;
    }

    event LogkrtClaimed(address indexed _recipient, uint256  _allocation, uint256 _totalAllocated, uint256 _grandTotalClaimed);

    constructor (uint256 _startTime,address _token_address) public {
         require(_startTime >= now);
         startTime = _startTime;
         token_address=_token_address;
    }

    
    function setAirdropAdmin(address _admin, bool _isAdmin) public onlyOwner {
        airdropAdmins[_admin] = _isAdmin;
    }

    
    function setAllocation (address _recipient, uint256 _totalAllocated) onlyOwner public {
         require(_recipient != address(0));
         allocations[_recipient] = Allocation(uint8(AllocationType.AIRDROP), _totalAllocated,false);
    }

    function massAllocations(address[] memory _recipients, uint256[] memory  _allocations) onlyOwner public {
        for (uint256 index = 0; index < _recipients.length; index++) {
            address _recipient=_recipients[index];
            if(_recipient != address(0)){
                allocations[_recipient] = Allocation(uint8(AllocationType.AIRDROP), _allocations[index],false);
            }
        }
    }

    
    function airdropTokens(address[] memory _recipient) public onlyOwnerOrAdmin {
        require(now >= startTime);
        for(uint256 i = 0; i< _recipient.length; i++){
             if (!airdrops[_recipient[i]] && allocations[_recipient[i]].delivered==false) {
                airdrops[_recipient[i]] = true;
                transferTokens(_recipient[i]);
            }
        }
    }

    
    function transferTokens (address _recipient) private{
        require(now >= startTime);
        uint256 tokensToTransfer = allocations[_recipient].allocation;
        require(ERC20Mintable(token_address).mint(_recipient, tokensToTransfer * decimalFactor));
        allocations[_recipient].delivered=true;
        grandTotalClaimed = grandTotalClaimed.add(tokensToTransfer);
        emit LogkrtClaimed(_recipient, allocations[_recipient].allocation, tokensToTransfer, grandTotalClaimed);
    }


}