// 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);
    }
}

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

pragma solidity ^0.8.0;

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

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor() {
        _paused = false;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        require(!paused(), "Pausable: paused");
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        require(paused(), "Pausable: not paused");
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}

// SPDX-License-Identifier: MIT
// 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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/IERC20Permit.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// 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;
    }
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Callback for IUniswapV3PoolActions#swap
/// @notice Any contract that calls IUniswapV3PoolActions#swap must implement this interface
interface IUniswapV3SwapCallback {
    /// @notice Called to `msg.sender` after executing a swap via IUniswapV3Pool#swap.
    /// @dev In the implementation you must pay the pool tokens owed for the swap.
    /// The caller of this method must be checked to be a UniswapV3Pool deployed by the canonical UniswapV3Factory.
    /// amount0Delta and amount1Delta can both be 0 if no tokens were swapped.
    /// @param amount0Delta The amount of token0 that was sent (negative) or must be received (positive) by the pool by
    /// the end of the swap. If positive, the callback must send that amount of token0 to the pool.
    /// @param amount1Delta The amount of token1 that was sent (negative) or must be received (positive) by the pool by
    /// the end of the swap. If positive, the callback must send that amount of token1 to the pool.
    /// @param data Any data passed through by the caller via the IUniswapV3PoolActions#swap call
    function uniswapV3SwapCallback(
        int256 amount0Delta,
        int256 amount1Delta,
        bytes calldata data
    ) external;
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.7.5;
pragma abicoder v2;

import '@uniswap/v3-core/contracts/interfaces/callback/IUniswapV3SwapCallback.sol';

/// @title Router token swapping functionality
/// @notice Functions for swapping tokens via Uniswap V3
interface ISwapRouter is IUniswapV3SwapCallback {
    struct ExactInputSingleParams {
        address tokenIn;
        address tokenOut;
        uint24 fee;
        address recipient;
        uint256 deadline;
        uint256 amountIn;
        uint256 amountOutMinimum;
        uint160 sqrtPriceLimitX96;
    }

    /// @notice Swaps `amountIn` of one token for as much as possible of another token
    /// @param params The parameters necessary for the swap, encoded as `ExactInputSingleParams` in calldata
    /// @return amountOut The amount of the received token
    function exactInputSingle(ExactInputSingleParams calldata params) external payable returns (uint256 amountOut);

    struct ExactInputParams {
        bytes path;
        address recipient;
        uint256 deadline;
        uint256 amountIn;
        uint256 amountOutMinimum;
    }

    /// @notice Swaps `amountIn` of one token for as much as possible of another along the specified path
    /// @param params The parameters necessary for the multi-hop swap, encoded as `ExactInputParams` in calldata
    /// @return amountOut The amount of the received token
    function exactInput(ExactInputParams calldata params) external payable returns (uint256 amountOut);

    struct ExactOutputSingleParams {
        address tokenIn;
        address tokenOut;
        uint24 fee;
        address recipient;
        uint256 deadline;
        uint256 amountOut;
        uint256 amountInMaximum;
        uint160 sqrtPriceLimitX96;
    }

    /// @notice Swaps as little as possible of one token for `amountOut` of another token
    /// @param params The parameters necessary for the swap, encoded as `ExactOutputSingleParams` in calldata
    /// @return amountIn The amount of the input token
    function exactOutputSingle(ExactOutputSingleParams calldata params) external payable returns (uint256 amountIn);

    struct ExactOutputParams {
        bytes path;
        address recipient;
        uint256 deadline;
        uint256 amountOut;
        uint256 amountInMaximum;
    }

    /// @notice Swaps as little as possible of one token for `amountOut` of another along the specified path (reversed)
    /// @param params The parameters necessary for the multi-hop swap, encoded as `ExactOutputParams` in calldata
    /// @return amountIn The amount of the input token
    function exactOutput(ExactOutputParams calldata params) external payable returns (uint256 amountIn);
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

/// @title KyotoPay
/// Version 1.0 

import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
import {Pausable} from "@openzeppelin/contracts/security/Pausable.sol";
import {ISwapRouter} from "@uniswap/v3-periphery/contracts/interfaces/ISwapRouter.sol";
import {IKyotoPay} from "./interfaces/IKyotoPay.sol";
import {IWETH9} from "./interfaces/IWETH9.sol";

contract KyotoPay is Ownable, Pausable, IKyotoPay {
    using SafeERC20 for IERC20;

    uint256 public constant DECIMALS = 10_000;

    // MAX_ADMIN_FEE is denominated in DECIMALs.  I.e. 500 = 5%
    uint256 public constant MAX_ADMIN_FEE = 500;

    address public immutable uniswapSwapRouterAddress;
    address public immutable wethAddress;

    // adminFee is denominated in DECIMALS.  For example, a value for fee of 200 = 2%
    uint256 public adminFee;

    // mapping for prferences
    mapping(address => Preferences) public recipientPreferences;
    mapping(address => bool) public whitelistedInputTokens;
    mapping(address => bool) public whitelistedOutputTokens;

    constructor(uint256 _adminFee, address _uniswapSwapRouterAddress, address _wethAddress) {
        if (_adminFee > MAX_ADMIN_FEE) revert InvalidAdminFee();
        if (_uniswapSwapRouterAddress == address(0)) revert ZeroAddress();
        if (_wethAddress == address(0)) revert ZeroAddress();

        adminFee = _adminFee;
        uniswapSwapRouterAddress = _uniswapSwapRouterAddress;
        wethAddress = _wethAddress;
    }

    /**
     * @notice sets the sender's receiving preferences. 
     * @param _preferences the sender's given preferences
     * Note: slippageAllowed is inversed. For example, 9_900 is 1% slippage
     * Requirements:
     *  - '_preferences.slippageAllowed' is not 0% (i.e. >= 10,000) or 100% (i.e. 0)
     *  - '_preferences.tokenAddress' is a valid output token found in whitelistedOutputTokens
     */
    function setPreferences(Preferences calldata _preferences) external whenNotPaused {
        if ((_preferences.slippageAllowed == 0) || (_preferences.slippageAllowed >= DECIMALS)) {
            revert InvalidRecipientSlippage();
        }
        if (!(whitelistedOutputTokens[_preferences.tokenAddress])) revert InvalidRecipientToken();

        recipientPreferences[msg.sender] = _preferences;
    }

    /**
     * @notice pays a recipient in their preferred token from a given input token
     * @param _recipient the recipient to pay
     * @param _tokenIn the token to send
     * @param _amountIn the amount of tokens to send 
     * @param _amountOut estimate of the Uniswap output of recipient's preferred token. Calculated on the frontend
     * @param _uniFee a Uniswap fee for a given pool
     * @param _data data about the transaction to be indexed
     * Requirements: 
     *  - '_recipient' != address(0)
     *  - '_tokenIn' is a valid input token
     *  - '_amountIn' != 0 
     *  - 'amountOut' != 0
     *  - '_uniFee' is a valid Uniswap pool fee
     *  - The executed swap will send the recipient more tokens than their slippageAllowed * '_amountOut'
     *  - The user's token balance > '_amountIn'
     *  - The user has approve the contract to transfer their tokens
     */ 
    function pay(
        address _recipient,
        address _tokenIn,
        uint256 _amountIn,
        uint256 _amountOut,
        uint24 _uniFee,
        bytes32 _data
    ) external whenNotPaused {
        _validateInputParams(_recipient, _tokenIn, _amountIn, _amountOut, _uniFee);

        // transfer the amount to this contract (should fail if the contract will not allow it)
        _getSenderFunds(_tokenIn, _amountIn);

        _pay(_recipient, _tokenIn, _amountIn, _amountOut, _uniFee, _data);
    }

    /**
     * @notice pays a recipient in their preferred token from the given ether
     * @param _recipient the recipient to pay
     * @param _amountOut estimate of the Uniswap output of recipient's preferred token. Calculated on the frontend
     * @param _uniFee a Uniswap fee for a given pool
     * @param _data data about the transaction to be indexed
     * Note: if the user has not set their preferences, they will receive WETH and not ETH
     * Requirements: 
     *  - '_recipient' != address(0)
     *  -  WETH is a whitelisted input
     *  -  msg.value > 0
     *  - 'amountOut' != 0
     *  - '_uniFee' is a valid Uniswap pool fee
     *  - The executed swap will send the recipient more tokens than their slippageAllowed * '_amountOut'
     */

    function payEth(address _recipient, uint256 _amountOut, uint24 _uniFee, bytes32 _data) external payable whenNotPaused {
        // Cache vars
        uint256 _msgValue = msg.value;
        address _wethAddress = wethAddress;

        _validateInputParams(_recipient, _wethAddress, _msgValue, _amountOut, _uniFee);

        IWETH9(_wethAddress).deposit{value: _msgValue}();

        _pay(_recipient, wethAddress, _msgValue, _amountOut, _uniFee, _data);
    }

    /*******************************
     *
     *       Internal functions
     *
     ******************************/

     /**
      * @dev validates preferences, gets recipient funds, executes the UNI swap, sends funds to recipient
      * Does not execute a UNI swap if the input token is the same as the output token or if the recipient has not set preferences
      * Instead, _pay will send the user funds directly to the recipient after a fee
      */
    function _pay(
        address _recipient,
        address _tokenIn,
        uint256 _amountIn,
        uint256 _amountOut,
        uint24 _uniFee,
        bytes32 _data
    ) internal {
        // Cache the recipient's preferences
        Preferences memory _preferences = recipientPreferences[_recipient];
        bool areValidPreferences = _validatePreferences(_preferences);

        // If the sender's token is the recipient's preferred token or recipient's preferences haven't been set, transfer directly and stop execution
        if ((_tokenIn == _preferences.tokenAddress) || !(areValidPreferences)) {
            _sendRecipientFunds(_tokenIn, _recipient, _amountIn);
            emit Payment(_recipient, _tokenIn, _amountIn, _data);

            return;
        }

        uint256 swapOutput = _executeSwap(
            _tokenIn, _preferences.tokenAddress, _amountIn, _amountOut, _uniFee, _preferences.slippageAllowed
        );

        // transfer funds to recipient (will pay the owners here too)
        _sendRecipientFunds(_preferences.tokenAddress, _recipient, swapOutput);

        // emit any data for end user use
        emit Payment(_recipient, _tokenIn, _amountIn, _data);
    }
    /**
     * @dev internal function to execute a swap using the Uniswap Swap Router
     * Uses the recipient's set slippage for amountOut
     */
    function _executeSwap(
        address _tokenIn,
        address _tokenOut,
        uint256 _amountIn,
        uint256 _amountOut,
        uint24 _uniFee,
        uint96 _slippageAllowed
    ) internal returns (uint256) {
        IERC20(_tokenIn).safeApprove(uniswapSwapRouterAddress, _amountIn);

        // create the input params
        ISwapRouter.ExactInputSingleParams memory params = ISwapRouter.ExactInputSingleParams({
            tokenIn: _tokenIn,
            tokenOut: _tokenOut,
            fee: _uniFee, // e.g. fee for a pool at 0.3% tier is 3000
            recipient: address(this), // this contract will be doing the distribution of funds
            deadline: block.timestamp,
            amountIn: _amountIn,
            amountOutMinimum: ((_amountOut * uint256(_slippageAllowed)) / DECIMALS),
            sqrtPriceLimitX96: 0 // sets a limit for the price that the swap will push to the pool (setting to 0 makes it inactive) --> will require more research
        });

        // swap currency on uniswap
        return ISwapRouter(uniswapSwapRouterAddress).exactInputSingle(params);
    }
    /**
     * @dev Internal function to validate input parameters. Reverts if given invalid input params.
     * Note: Uniswap fees for pools are 0.01%, 0.05%, 0.30%, and 1.00%
     * They are represented in hundredths of basis points.  I.e. 100 = 0.01%, 500 = 0.05%, etc.
     */

    function _validateInputParams(
        address _recipient,
        address _tokenIn,
        uint256 _amountIn,
        uint256 _amountOut,
        uint24 _uniFee
    ) internal view {
        require(((_uniFee == 100) || (_uniFee == 500) || (_uniFee == 3000) || (_uniFee == 10_000)), "Invalid Uni Fee");
        if (!(whitelistedInputTokens[_tokenIn])) revert InvalidToken();
        if (_recipient == address(0)) revert ZeroAddress();
        if (_amountIn == 0 || _amountOut == 0) revert InvalidAmount();
    }

    /**
     * @dev validates recipient's preferences.  Does not revert.
     * @return true when valid preferences, false when invalid
     */
    function _validatePreferences(Preferences memory _preferences) internal view returns (bool) {
        return ((_preferences.slippageAllowed != 0) && (whitelistedOutputTokens[_preferences.tokenAddress]));
    }

    /**
     * @dev safe transfers funds from the user to address(this)
     */
    function _getSenderFunds(address _tokenAddress, uint256 _amountIn) internal {
        IERC20(_tokenAddress).safeTransferFrom(msg.sender, address(this), _amountIn);
    }

    /**
     * @dev safeTransfer tokens to a given recipient given a ERC20 token address and amount to send
     */ 
    function _sendRecipientFunds(address _tokenAddress, address _recipient, uint256 _amount) internal {
        // calculate the owner payment, this amount will stay in the contract and can be withdrawn at will (no reason to make superfluous transfers)
        uint256 ownerPayment = (_amount * adminFee) / DECIMALS;

        // pay the recipient the excess
        IERC20(_tokenAddress).safeTransfer(_recipient, _amount - ownerPayment);
    }

    /*******************************
     *
     *       Admin functions
     *
     ******************************/

    /**
     * @dev Admin function to set the fee
     * @param _adminFee the new fee amount
     * Requirements:
     *  - 'adminFee" <= 'MAX_ADMIN_FEE'
     *  - msg.sender is the owner
     */
    function setAdminFee(uint256 _adminFee) external onlyOwner {
        if (_adminFee > MAX_ADMIN_FEE) revert InvalidAdminFee();
        adminFee = _adminFee;
    }

    /**
     * @dev Admin function to add a token to the input whitelist
     * @param _token the address of the token
     * Requirements:
     *  - '_token" != address(0)
     *  - msg.sender is the owner
     */
    function addToInputWhitelist(address _token) external onlyOwner {
        if (_token == address(0)) revert ZeroAddress();
        whitelistedInputTokens[_token] = true;
    }

    /**
     * @dev Admin function to revoke a token from the input whitelist
     * @param _token the address of the token
     * Requirements:
     *  - '_token" != address(0)
     *  - msg.sender is the owner
     */
    function revokeFromInputWhitelist(address _token) external onlyOwner {
        if (_token == address(0)) revert ZeroAddress();
        delete whitelistedInputTokens[_token];
    }

    /**
     * @dev Admin function to add a token to the output whitelist
     * @param _token the address of the token
     * Requirements:
     *  - '_token" != address(0)
     *  - msg.sender is the owner
     */
    function addToOutputWhitelist(address _token) external onlyOwner {
        if (_token == address(0)) revert ZeroAddress();
        whitelistedOutputTokens[_token] = true;
    }

    /**
     * @dev Admin function to revoke a token from the output whitelist
     * @param _token the address of the token
     * Requirements:
     *  - '_token" != address(0)
     *  - msg.sender is the owner
     */
    function revokeFromOutputWhitelist(address _token) external onlyOwner {
        if (_token == address(0)) revert ZeroAddress();
        delete whitelistedOutputTokens[_token];
    }

    /**
     * @dev Admin function to withdraw tokens from a given token address
     * Note: '_token' is not validated before passing it in as an argument
     * '_token' must always be verified manually before being called by the admin
     * @param _token the address of the token to withdraw
     * @param _amount the amount of token to withdraw
     * Requirements: 
     * Requirements:
     *  - '_token" != address(0)
     *  - msg.sender is the owner
     *  - Token balance of address(this) > 0
     */
    function withdraw(address _token, uint256 _amount) external onlyOwner {
        if (IERC20(_token).balanceOf(address(this)) == 0) revert ZeroBalance();
        IERC20(_token).safeTransfer(msg.sender, _amount);
    }

    /**
     * @dev Admin function to pause payments
     */
    function pause() external onlyOwner {
        _pause();
    }

    /**
     * @dev Admin function to unpause payments
     */
    function unpause() external onlyOwner {
        _unpause();
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

/// @title Interface for KyotoPay
/// Version 1.0

interface IKyotoPay {

    struct Preferences {
        address tokenAddress;
        uint96 slippageAllowed;
    }

    /**
     *  Invalid value(s) for arguments 'amountIn' or '_amountOut'.  '_amountIn' is zero or '_amountOut' is zero
     */
    error InvalidAmount();

    /**
     *  Argument '_fee' in setFee cannot be greater than MAX_FEE
     */
    error InvalidAdminFee();

    /**
     *  Argument '_tokenIn' is not a valid input token
     */
    error InvalidToken();

    /**
     *  Argument '_preferences.slippageAllowed' is invalid: it is zero or greater than the decimal values
     */
    error InvalidRecipientSlippage();

    /**
     * Argument '_preferences.tokenAddress' is not a valid whitelisted output token found in 'whitelistedOutputTokens'
     */
    error InvalidRecipientToken();

    /**
     * Passed in address is address(0)
     */
    error ZeroAddress();

    /**
     * address(this) has a token balance of 0 for the passed in '_tokenAddress"
     */
    error ZeroBalance();

    /**
     * Emitted to pass data from payment function
     */
    event Payment(address recipient, address indexed tokenAddress, uint256 indexed amountIn, bytes32 indexed data);

    /**
     * Sets the sender's receiving preferences. 
     * Note: slippageAllowed is inversed. For example, 9_900 is 1% slippage
     * Requirements:
     *  - '_preferences.slippageAllowed' is not 0% (i.e. >= 10,000) or 100% (i.e. 0)
     *  - '_preferences.tokenAddress' is a valid output token found in whitelistedOutputTokens
     */
    function setPreferences(Preferences calldata _preferences) external;

    /**
     * Pays a recipient in their preferred token from a given input token
     * Requirements: 
     *  - '_recipient' != address(0)
     *  - '_tokenIn' is a valid input token
     *  - '_amountIn' != 0 
     *  - 'amountOut' != 0
     *  - '_uniFee' is a valid Uniswap pool fee
     *  - The executed swap will send the recipient more tokens than their slippageAllowed * '_amountOut'
     *  - The user's token balance > '_amountIn'
     *  - The user has approve the contract to transfer their tokens
     */ 
    function pay( address _recipient, address _tokenIn, uint256 _amountIn, uint256 _amountOut, uint24 _uniFee, bytes32 _data) external;

    /**
     * Pays a recipient in their preferred token from the given ether
     * Note: if the user has not set their preferences, they will receive WETH and not ETH
     * Requirements: 
     *  - '_recipient' != address(0)
     *  -  WETH is a whitelisted input
     *  -  msg.value > 0
     *  - 'amountOut' != 0
     *  - '_uniFee' is a valid Uniswap pool fee
     *  - The executed swap will send the recipient more tokens than their slippageAllowed * '_amountOut'
     */

    function payEth(address _recipient, uint256 _amountOut, uint24 _uniFee, bytes32 _data) external payable;
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

/// @title Interface for WETH9
interface IWETH9 is IERC20 {
    // Deposit ether to get wrapped ether
    function deposit() external payable;

    // Withdraw wrapped ether to get ether
    function withdraw(uint256) external;
}