pragma solidity ^0.4.7;

contract Ownable {
  address public owner;

  constructor() public {
    owner = msg.sender;
  }

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

contract Simple_DAICO is Ownable {

    address receiver;
    uint block_allowance;
    uint available_to_withdraw = 0;
    uint last_update_block;

    modifier onlyReceiver() {
        require(msg.sender == receiver);
        _;
    }

    constructor(address receiver_addr, uint starting_allowance) payable {
        super();
        block_allowance = starting_allowance;
        last_update_block = block.number;
        receiver = receiver_addr;
    }

    function setAllowance(uint new_allowance) public onlyOwner {
        available_to_withdraw += block_allowance * (block.number - last_update_block);
        block_allowance = new_allowance;
        last_update_block = block.number;
    }

    function destroyContract() public onlyOwner {
        suicide(owner);
    }

    function withdraw() public onlyReceiver {
        available_to_withdraw += block_allowance * (block.number - last_update_block);
        receiver.transfer(available_to_withdraw);
        available_to_withdraw = 0;
        last_update_block = block.number;
    }

}