// SPDX-License-Identifier: BSD
pragma solidity ^0.8.4;

/// @title Clone
/// @author zefram.eth
/// @notice Provides helper functions for reading immutable args from calldata
contract Clone {
    /// @notice Reads an immutable arg with type address
    /// @param argOffset The offset of the arg in the packed data
    /// @return arg The arg value
    function _getArgAddress(uint256 argOffset) internal pure returns (address arg) {
        uint256 offset = _getImmutableArgsOffset();
        // solhint-disable-next-line no-inline-assembly
        assembly ("memory-safe") {
            arg := shr(0x60, calldataload(add(offset, argOffset)))
        }
    }

    /// @notice Reads an immutable arg with type uint256
    /// @param argOffset The offset of the arg in the packed data
    /// @return arg The arg value
    function _getArgUint256(uint256 argOffset) internal pure returns (uint256 arg) {
        uint256 offset = _getImmutableArgsOffset();
        // solhint-disable-next-line no-inline-assembly
        assembly ("memory-safe") {
            arg := calldataload(add(offset, argOffset))
        }
    }

    /// @notice Reads a uint256 array stored in the immutable args.
    /// @param argOffset The offset of the arg in the packed data
    /// @param arrLen Number of elements in the array
    /// @return arr The array
    function _getArgUint256Array(uint256 argOffset, uint64 arrLen) internal pure returns (uint256[] memory arr) {
        uint256 offset = _getImmutableArgsOffset();
        uint256 el;
        arr = new uint256[](arrLen);
        for (uint64 i = 0; i < arrLen; i++) {
            // solhint-disable-next-line no-inline-assembly
            assembly ("memory-safe") {
                el := calldataload(add(add(offset, argOffset), mul(i, 32)))
            }
            arr[i] = el;
        }
        return arr;
    }

    /// @notice Reads an immutable arg with type uint88
    /// @param argOffset The offset of the arg in the packed data
    /// @return arg The arg value
    function _getArgUint88(uint256 argOffset) internal pure returns (uint88 arg) {
        uint256 offset = _getImmutableArgsOffset();
        // solhint-disable-next-line no-inline-assembly
        assembly ("memory-safe") {
            arg := shr(0xa8, calldataload(add(offset, argOffset)))
        }
    }

    /// @notice Reads an immutable arg with type uint8
    /// @param argOffset The offset of the arg in the packed data
    /// @return arg The arg value
    function _getArgUint8(uint256 argOffset) internal pure returns (uint8 arg) {
        uint256 offset = _getImmutableArgsOffset();
        // solhint-disable-next-line no-inline-assembly
        assembly ("memory-safe") {
            arg := shr(0xf8, calldataload(add(offset, argOffset)))
        }
    }

    /// @notice Reads an immutable arg with type bool
    /// @param argOffset The offset of the arg in the packed data
    /// @return arg The arg value
    function _getArgBool(uint256 argOffset) internal pure returns (bool arg) {
        uint256 offset = _getImmutableArgsOffset();
        // solhint-disable-next-line no-inline-assembly
        assembly ("memory-safe") {
            arg := shr(0xf8, calldataload(add(offset, argOffset)))
        }
    }

    /// @return offset The offset of the packed immutable args in calldata
    function _getImmutableArgsOffset() internal pure returns (uint256 offset) {
        // solhint-disable-next-line no-inline-assembly
        assembly ("memory-safe") {
            offset := sub(calldatasize(), add(shr(240, calldataload(sub(calldatasize(), 2))), 2))
        }
    }
}