// File: contracts/Proxy.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/access/Ownable.sol";

contract Proxy is Ownable{
    bytes32 private constant implementationPosition =
        keccak256("implementation.contract.frac:2022");
    bytes32 private constant proxyOwnerPosition =
        keccak256("owner.contract.frac:2022");

    event Upgraded(address indexed implementation);
    event ProxyOwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    constructor() {
        _setUpgradeabilityOwner(msg.sender);
    }

    modifier onlyProxyOwner() {
        require(msg.sender == proxyOwner());
        _;
    }

    /**
     * @dev To get the address of the proxy contract's owner
     */
    function proxyOwner() public view returns (address owner) {
        bytes32 position = proxyOwnerPosition;
        assembly {
            owner := sload(position)
        }
    }

    /**
     * @dev To get the address of the proxy contract
     */
    function implementation() public view returns (address impl) {
        bytes32 position = implementationPosition;
        assembly {
            impl := sload(position)
        }
    }

    /**
     * @dev  To get the address of the proxy contract
     */
    function transferProxyOwnership(address _newOwner) public onlyProxyOwner {
        require(
            _newOwner != address(0),
            "Transfer proxy ownership to zero address"
        );
        require(
            _newOwner != proxyOwner(),
            "Transfer proxy ownership to current owner"
        );
        emit ProxyOwnershipTransferred(proxyOwner(), _newOwner);
        _setUpgradeabilityOwner(_newOwner);
    }

    /**
     * @dev To upgrade the logic contract to new one
     */
    function upgradeTo(address _newImplementation) public onlyProxyOwner {
        address currentImplementation = implementation();
        require(currentImplementation != _newImplementation);
        _setImplementation(_newImplementation);
        emit Upgraded(_newImplementation);
    }

    function _setImplementation(address _newImplementation) internal {
        bytes32 position = implementationPosition;
        assembly {
            sstore(position, _newImplementation)
        }
    }

    function _setUpgradeabilityOwner(address _newProxyOwner) internal {
        bytes32 position = proxyOwnerPosition;
        assembly {
            sstore(position, _newProxyOwner)
        }
    }

    function _delegatecall() internal {
        address _impl = implementation();
        require(_impl != address(0), "Impl address is 0");

        assembly {
            let ptr := mload(0x40)
            calldatacopy(ptr, 0, calldatasize())
            let result := delegatecall(
                sub(gas(), 10000),
                _impl,
                ptr,
                calldatasize(),
                0,
                0
            )
            let size := returndatasize()
            returndatacopy(ptr, 0, size)

            switch result
            case 0 {
                revert(ptr, size)
            }
            default {
                return(ptr, size)
            }
        }
    }

    fallback() external payable {
        _delegatecall();
    }

    receive() external payable {}
}

// 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);
    }
}

// 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;
    }
}