// File: /contracts/BoxBuyer.sol



// SPDX-License-Identifier: GPL-3.0
// solhint-disable-next-line
pragma solidity 0.8.12;

import "@openzeppelin/contracts/access/Ownable.sol";
import "./interface/IMasterContract.sol";

/// @title Bulls and Apes Project - Buy Special LootBoxes
/// @author BAP Dev Team
/// @notice Helper Contract to buy special LootBoxes
contract BoxBuyer is Ownable {    
    /// @notice Address of the signer wallet
    address public secret;

    // @notice mapping for used signatures
    mapping(bytes => bool) public isSignatureUsed;

    /// @notice Event emitted when lootbox is bought
    event BoxBought(uint256 amount, uint256 boxType, address recipient, address operator);   

    /// @notice Deploys the contract
    /// @param _secret Address of the signer wallet
    constructor(address _secret) {     
        secret = _secret;
    }

    /// @notice Helper function to buy a special lootbox
    /// @param amount Amount of boxes to buy
    /// @param boxType Type of the lootbox to buy
    /// @param price Price to be paid for the lootbox (in ETH)
    /// @param timeOut Timestamp for signature expiration
    /// @param recipient Address to send the lootbox to
    /// @param signature Signature to verify above parameters
    function buyLootbox(uint256 amount, uint256 boxType, uint256 price, uint256 timeOut, address recipient, bytes memory signature) external payable {
        require(timeOut > block.timestamp, "buyLootbox: Seed is no longer valid");
        require(price > 0, "buyLootbox: amount is not valid");
        require(msg.value >= price, "buyLootbox: not enough ETH to buy");
        // check signature
        require(!isSignatureUsed[signature], "buyLootbox: Signature is already used");
        require(_verifyHashSignature(keccak256(abi.encode(amount, boxType, price, timeOut, recipient)), signature), "buyLootbox: Signature is invalid");

        isSignatureUsed[signature] = true;

        if (msg.value > price) {
            (bool success, ) = msg.sender.call{value: msg.value - price}("");
            require(success, "buyLootbox: Unable to send refund eth");
        }

        emit BoxBought(amount, boxType, recipient, msg.sender);
    }    

    /// @notice Change the signer address
    /// @param _secret new signer for encrypted signatures
    /// @dev Can only be called by the contract owner
    function setSecret(address _secret) external onlyOwner {
        secret = _secret;
    }

    function _verifyHashSignature(
        bytes32 freshHash,
        bytes memory signature
    ) internal view returns (bool) {
        bytes32 hash = keccak256(
            abi.encodePacked("\x19Ethereum Signed Message:\n32", freshHash)
        );

        bytes32 r;
        bytes32 s;
        uint8 v;

        if (signature.length != 65) {
            return false;
        }
        assembly {
            r := mload(add(signature, 32))
            s := mload(add(signature, 64))
            v := byte(0, mload(add(signature, 96)))
        }

        if (v < 27) {
            v += 27;
        }

        address signer = address(0);
        if (v == 27 || v == 28) {
            // solium-disable-next-line arg-overflow
            signer = ecrecover(hash, v, r, s);
        }
        return secret == signer;
    }
}

// File: /contracts/interface/IMasterContract.sol



// SPDX-License-Identifier: GPL-3.0
// solhint-disable-next-line
pragma solidity 0.8.12;

interface IMasterContract {
    // METH functions

    function claim(address to, uint256 amount) external;

    function pay(uint256 payment, uint256 fee) external;

    // Teens functions

    function airdrop(address to, uint256 amount) external;

    function burnTeenBull(uint256 tokenId) external;

    // Utilities functions

    function burn(uint256 id, uint256 amount) external;

    function airdrop(
        address to,
        uint256 amount,
        uint256 id
    ) external;
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// 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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @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 Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        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);
    }
}