// File: CoinBank.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.0;

import "./IERC20.sol";

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a + b;
        require(c >= a);
    }
    function div(uint256 a, uint256 b) internal pure returns (uint256 c) {
        require(b > 0);
        c = a / b;
    }
    function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a * b;
        require(a == 0 || c / a == b);
    }
    function sub(uint256 a, uint256 b) internal pure returns (uint256 c) {
        require(b <= a);
        c = a - b;
    }
}

//----------------------------------------------------------------------------------

contract CoinBank{
    using SafeMath for uint256;

    address payable public owner;
    address coin;
    uint256 priceForMCoins;
    
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor (address coinAddress) {
        coin = coinAddress;
        owner = payable(msg.sender);
   }
    
    function buy1000000x(uint256 amount) public payable{
        require(IERC20(coin).balanceOf(address(this)) >= SafeMath.mul(amount,1000000));
        require(msg.value >= SafeMath.mul(amount, priceForMCoins));
        require(priceForMCoins > 0);
        IERC20(coin).transfer(msg.sender, SafeMath.mul(amount,1000000));
    }
    
    function mCoinPrice() public view returns (uint256 price){
        return priceForMCoins;
    }
    
    function payout() public {
        require(msg.sender == owner);
        owner.transfer(address(this).balance);
    }
    
    function reclaimCoins() public {
        require(msg.sender == owner);
        IERC20(coin).transfer(msg.sender, totalSupply());
    }
    
    function setPriceFor1M(uint256 price) public {
        require(owner == msg.sender);
        priceForMCoins = price;
    }
    
    function totalSupply() public view returns (uint256 supply){
        return IERC20(coin).balanceOf(address(this));
    }
    
    function transferOwnership(address newOwner) public {    
        require(owner == msg.sender, "Only owner");
        require(newOwner != address(0), "Zero address");
        emit OwnershipTransferred(owner, newOwner);
        owner.transfer(address(this).balance);
        owner = payable(newOwner);
    }
}
// File: IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: 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
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}