// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

type TakerTraits is uint256;

/**
 * @title TakerTraitsLib
 * @notice This library to manage and check TakerTraits, which are used to encode the taker's preferences for an order in a single uint256.
 * @dev The TakerTraits are structured as follows:
 * High bits are used for flags
 * 255 bit `_MAKER_AMOUNT_FLAG`           - If set, the taking amount is calculated based on making amount, otherwise making amount is calculated based on taking amount.
 * 254 bit `_UNWRAP_WETH_FLAG`            - If set, the WETH will be unwrapped into ETH before sending to taker.
 * 253 bit `_SKIP_ORDER_PERMIT_FLAG`      - If set, the order skips maker's permit execution.
 * 252 bit `_USE_PERMIT2_FLAG`            - If set, the order uses the permit2 function for authorization.
 * 251 bit `_ARGS_HAS_TARGET`             - If set, then first 20 bytes of args are treated as target address for maker’s funds transfer.
 * 224-247 bits `ARGS_EXTENSION_LENGTH`   - The length of the extension calldata in the args.
 * 200-223 bits `ARGS_INTERACTION_LENGTH` - The length of the interaction calldata in the args.
 * 0-184 bits                             - The threshold amount (the maximum amount a taker agrees to give in exchange for a making amount).
 */
library TakerTraitsLib {
    uint256 private constant _MAKER_AMOUNT_FLAG = 1 << 255;
    uint256 private constant _UNWRAP_WETH_FLAG = 1 << 254;
    uint256 private constant _SKIP_ORDER_PERMIT_FLAG = 1 << 253;
    uint256 private constant _USE_PERMIT2_FLAG = 1 << 252;
    uint256 private constant _ARGS_HAS_TARGET = 1 << 251;

    uint256 private constant _ARGS_EXTENSION_LENGTH_OFFSET = 224;
    uint256 private constant _ARGS_EXTENSION_LENGTH_MASK = 0xffffff;
    uint256 private constant _ARGS_INTERACTION_LENGTH_OFFSET = 200;
    uint256 private constant _ARGS_INTERACTION_LENGTH_MASK = 0xffffff;

    uint256 private constant _AMOUNT_MASK = 0x000000000000000000ffffffffffffffffffffffffffffffffffffffffffffff;

    /**
     * @notice Checks if the args should contain target address.
     * @param takerTraits The traits of the taker.
     * @return result A boolean indicating whether the args should contain target address.
     */
    function argsHasTarget(TakerTraits takerTraits) internal pure returns (bool) {
        return (TakerTraits.unwrap(takerTraits) & _ARGS_HAS_TARGET) != 0;
    }

    /**
     * @notice Retrieves the length of the extension calldata from the takerTraits.
     * @param takerTraits The traits of the taker.
     * @return result The length of the extension calldata encoded in the takerTraits.
     */
    function argsExtensionLength(TakerTraits takerTraits) internal pure returns (uint256) {
        return (TakerTraits.unwrap(takerTraits) >> _ARGS_EXTENSION_LENGTH_OFFSET) & _ARGS_EXTENSION_LENGTH_MASK;
    }

    /**
     * @notice Retrieves the length of the interaction calldata from the takerTraits.
     * @param takerTraits The traits of the taker.
     * @return result The length of the interaction calldata encoded in the takerTraits.
     */
    function argsInteractionLength(TakerTraits takerTraits) internal pure returns (uint256) {
        return (TakerTraits.unwrap(takerTraits) >> _ARGS_INTERACTION_LENGTH_OFFSET) & _ARGS_INTERACTION_LENGTH_MASK;
    }

    /**
     * @notice Checks if the taking amount should be calculated based on making amount.
     * @param takerTraits The traits of the taker.
     * @return result A boolean indicating whether the taking amount should be calculated based on making amount.
     */
    function isMakingAmount(TakerTraits takerTraits) internal pure returns (bool) {
        return (TakerTraits.unwrap(takerTraits) & _MAKER_AMOUNT_FLAG) != 0;
    }

    /**
     * @notice Checks if the order should unwrap WETH and send ETH to taker.
     * @param takerTraits The traits of the taker.
     * @return result A boolean indicating whether the order should unwrap WETH.
     */
    function unwrapWeth(TakerTraits takerTraits) internal pure returns (bool) {
        return (TakerTraits.unwrap(takerTraits) & _UNWRAP_WETH_FLAG) != 0;
    }

    /**
     * @notice Checks if the order should skip maker's permit execution.
     * @param takerTraits The traits of the taker.
     * @return result A boolean indicating whether the order don't apply permit.
     */
    function skipMakerPermit(TakerTraits takerTraits) internal pure returns (bool) {
        return (TakerTraits.unwrap(takerTraits) & _SKIP_ORDER_PERMIT_FLAG) != 0;
    }

    /**
     * @notice Checks if the order uses the permit2 instead of permit.
     * @param takerTraits The traits of the taker.
     * @return result A boolean indicating whether the order uses the permit2.
     */
    function usePermit2(TakerTraits takerTraits) internal pure returns (bool) {
        return (TakerTraits.unwrap(takerTraits) & _USE_PERMIT2_FLAG) != 0;
    }

    /**
     * @notice Retrieves the threshold amount from the takerTraits.
     * The maximum amount a taker agrees to give in exchange for a making amount.
     * @param takerTraits The traits of the taker.
     * @return result The threshold amount encoded in the takerTraits.
     */
    function threshold(TakerTraits takerTraits) internal pure returns (uint256) {
        return TakerTraits.unwrap(takerTraits) & _AMOUNT_MASK;
    }
}