// SPDX-License-Identifier: MIT
// File: @openzeppelin/contracts/utils/Context.sol


// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol


// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^0.8.0;


/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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);

    /**
     * @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 `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, 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 `from` to `to` 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 from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: IERC20Child.sol


pragma solidity ^0.8.0;

//Remix style import


//Brownie style import
//import { IERC20 } from "OpenZeppelin/openzeppelin-contracts@4.0.0/contracts/token/ERC20/IERC20.sol";

/// @dev Interface of the child ERC20 token, for use on sidechains and L2 networks.
interface IERC20Child is IERC20 {
  /**
   * @notice called by bridge gateway when tokens are deposited on root chain
   * Should handle deposits by minting the required amount for the recipient
   *
   * @param recipient an address for whom minting is being done
   * @param amount total amount to mint
   */
  function mint(
    address recipient,
    uint256 amount
  )
    external;

  /**
   * @notice called by bridge gateway when tokens are withdrawn back to root chain
   * @dev Should burn recipient's tokens.
   *
   * @param amount total amount to burn
   */
  function burn(
    uint256 amount
  )
    external;
}


// File: ethbridge.sol


pragma solidity ^0.8.0;




//ETH
contract BBLBridge is Ownable {

    event BridgeInitialized(uint indexed timestamp);
    event TokensBridged(address indexed requester, bytes32 indexed mainDepositHash, uint amount, uint timestamp);
    event TokensReturned(address indexed requester, bytes32 indexed sideDepositHash, uint amount, uint timestamp);
    
    IERC20Child private token;
    bool bridgeInitState;
    address gateway;
    uint256 public txFee = 1; //0.1%
    address public txFeeReceiver = msg.sender;

    constructor (address _gateway) {
        gateway = _gateway;
    }

    function initializeBridge(address _token) onlyOwner external {
        token = IERC20Child(_token);
        bridgeInitState = true;
    }

    function transferFromBSC(address _requester, uint _bridgedAmount, bytes32 _mainDepositHash) verifyInitialization onlyGateway  external {
        uint256 tokensForReceiver = _bridgedAmount * txFee / 1000;

        token.mint(_requester, _bridgedAmount - tokensForReceiver);
        if(txFee > 0) {
          token.mint(txFeeReceiver, tokensForReceiver);
        }

        emit TokensBridged(_requester, _mainDepositHash, _bridgedAmount, block.timestamp);
    }

    function transferToBSC(address _requester, uint _bridgedAmount, bytes32 _sideDepositHash) verifyInitialization onlyGateway external {
        token.burn(_bridgedAmount);
        emit TokensReturned(_requester, _sideDepositHash, _bridgedAmount, block.timestamp);
    }

    function setTxFee(uint256 _txFee) onlyOwner external {
        require(_txFee <= 50, "Fee is too high!");
        txFee = _txFee;
    }

    function setTxFeeReceiver(address _txFeeReceiver) onlyOwner external {
        txFeeReceiver = _txFeeReceiver;
    }

    modifier verifyInitialization {
      require(bridgeInitState, "Bridge has not been initialized!");
      _;
    }
    
    modifier onlyGateway {
      require(msg.sender == gateway, "Only gateway can execute this function!");
      _;
    }
}