/*******************************************************************************
 *   (c) 2022 Zondax AG
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 ********************************************************************************/
// THIS CODE WAS SECURITY REVIEWED BY KUDELSKI SECURITY, BUT NOT FORMALLY AUDITED

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.17;

import "../types/CommonTypes.sol";

/// @title Library containing miscellaneous functions used on the project
/// @author Zondax AG
library Misc {
    /// @notice the codec received is not valid
    error InvalidCodec(uint64);

    /// @notice filecoin method not handled
    error MethodNotHandled(uint64);

    uint64 constant DAG_CBOR_CODEC = 0x71;
    uint64 constant CBOR_CODEC = 0x51;
    uint64 constant NONE_CODEC = 0x00;

    // Code taken from Openzeppelin repo
    // Link: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/0320a718e8e07b1d932f5acb8ad9cec9d9eed99b/contracts/utils/math/SignedMath.sol#L37-L42
    /// @notice get the abs from a signed number
    /// @param n number to get abs from
    /// @return unsigned number
    function abs(int256 n) internal pure returns (uint256) {
        unchecked {
            // must be unchecked in order to support `n = type(int256).min`
            return uint256(n >= 0 ? n : -n);
        }
    }

    /// @notice validate if an address exists or not
    /// @dev read this article for more information https://blog.finxter.com/how-to-find-out-if-an-ethereum-address-is-a-contract/
    /// @param addr address to check
    /// @return whether the address exists or not
    function addressExists(address addr) internal view returns (bool) {
        bytes32 codehash;
        assembly {
            codehash := extcodehash(addr)
        }
        return codehash != 0x0;
    }

    /// Returns the data size required by CBOR.writeFixedNumeric
    function getPrefixSize(uint256 data_size) internal pure returns (uint256) {
        if (data_size <= 23) {
            return 1;
        } else if (data_size <= 0xFF) {
            return 2;
        } else if (data_size <= 0xFFFF) {
            return 3;
        } else if (data_size <= 0xFFFFFFFF) {
            return 5;
        }
        return 9;
    }

    function getBytesSize(bytes memory value) internal pure returns (uint256) {
        return getPrefixSize(value.length) + value.length;
    }

    function getCidSize(bytes memory value) internal pure returns (uint256) {
        return getPrefixSize(2) + value.length;
    }

    function getFilActorIdSize(CommonTypes.FilActorId value) internal pure returns (uint256) {
        uint64 val = CommonTypes.FilActorId.unwrap(value);
        return getPrefixSize(uint256(val));
    }

    function getChainEpochSize(CommonTypes.ChainEpoch value) internal pure returns (uint256) {
        int64 val = CommonTypes.ChainEpoch.unwrap(value);
        if (val >= 0) {
            return getPrefixSize(uint256(uint64(val)));
        } else {
            return getPrefixSize(uint256(uint64(-1 - val)));
        }
    }

    function getBoolSize() internal pure returns (uint256) {
        return getPrefixSize(1);
    }
}