/*

    Copyright 2020 DODO ZOO.
    SPDX-License-Identifier: Apache-2.0

*/

pragma solidity 0.8.16;

import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {IERC20Metadata} from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import {GSPTrader} from "./GSPTrader.sol";
import {GSPFunding} from "./GSPFunding.sol";
import {GSPVault} from "./GSPVault.sol";

/**
 * @title DODO GasSavingPool
 * @author DODO Breeder
 *
 * @notice DODO GasSavingPool initialization
 */
contract GSP is GSPTrader, GSPFunding {
    /**
     * @notice Function will be called in factory, init risk should not be included.
     * @param maintainer The dodo's address, who can claim mtFee and own this pool
     * @param admin oracle owner address, who can set price.
     * @param baseTokenAddress The base token address
     * @param quoteTokenAddress The quote token address
     * @param lpFeeRate The rate of lp fee, with 18 decimal
     * @param mtFeeRate The rate of mt fee, with 18 decimal
     * @param i The oracle price, possible to be changed only by maintainer
     * @param k The swap curve parameter
     * @param priceLimit The limit of the setting range of the I
     * @param isOpenTWAP Useless, always false, just for compatible with old version pool
     */
    function init(
        address maintainer,
        address admin,
        address baseTokenAddress,
        address quoteTokenAddress,
        uint256 lpFeeRate,
        uint256 mtFeeRate,
        uint256 i,
        uint256 k,
        uint256 priceLimit,
        bool isOpenTWAP
    ) external {
        // GSP can only be initialized once
        require(!_GSP_INITIALIZED_, "GSP_INITIALIZED");
        // _GSP_INITIALIZED_ is set to true after initialization
        _GSP_INITIALIZED_ = true;
        // baseTokenAddress and quoteTokenAddress should not be the same
        require(baseTokenAddress != quoteTokenAddress, "BASE_QUOTE_CAN_NOT_BE_SAME");
        // _BASE_TOKEN_ and _QUOTE_TOKEN_ should be valid ERC20 tokens
        _BASE_TOKEN_ = IERC20(baseTokenAddress);
        _QUOTE_TOKEN_ = IERC20(quoteTokenAddress);

        // i should be greater than 0 and less than 10**36
        require(i > 0 && i <= 10**36);
        _I_ = i;
        // k should be greater than 0 and less than 10**18
        require(k <= 10**18);
        _K_ = k;

        // _LP_FEE_RATE_ is set when initialization
        _LP_FEE_RATE_ = lpFeeRate;
        // _MT_FEE_RATE_ is set when initialization
        _MT_FEE_RATE_ = mtFeeRate;
        // _MAINTAINER_ is set when initialization, the address receives the fee
        _MAINTAINER_ = maintainer;
        _ADMIN_ = admin;

        _PRICE_LIMIT_ = priceLimit;
        // _IS_OPEN_TWAP_ is always false
        _IS_OPEN_TWAP_ = false;


        string memory connect = "_";
        string memory suffix = "GSP";
        // name of the shares is the combination of suffix, connect and string of the GSP
        name = string(abi.encodePacked(suffix, connect, addressToShortString(address(this))));
        // symbol of the shares is GLP
        symbol = "GLP";
        // decimals of the shares is the same as the base token decimals
        decimals = IERC20Metadata(baseTokenAddress).decimals();
        // initialize DOMAIN_SEPARATOR
        buildDomainSeparator();
        // ==========================================================================
    }

    // ============================== Permit ====================================
    /**
     * @notice DOMAIN_SEPARATOR is used for approve by signature
     */
    function buildDomainSeparator() public returns (bytes32){
        string memory connect = "_";
        string memory suffix = "GSP";
        // name of the shares is the combination of suffix, connect and string of the GSP
        string memory name = string(abi.encodePacked(suffix, connect, addressToShortString(address(this))));

        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                // keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                0x8b73c3c69bb8fe3d512ecc4cf759cc79239f7b179b0ffacaa9a75d522b39400f,
                keccak256(bytes(name)),
                keccak256(bytes("1")),
                block.chainid,
                address(this)
            )
        );
        return DOMAIN_SEPARATOR;
    }

    /**
     * @notice Convert the address to a shorter string
     * @param _addr The address to convert
     * @return A string representation of _addr in hexadecimal
     */
    function addressToShortString(address _addr) public pure returns (string memory) {
        bytes32 value = bytes32(uint256(uint160(_addr)));
        bytes memory alphabet = "0123456789abcdef";

        bytes memory str = new bytes(8);
        for (uint256 i = 0; i < 4; i++) {
            str[i * 2] = alphabet[uint8(value[i + 12] >> 4)];
            str[1 + i * 2] = alphabet[uint8(value[i + 12] & 0x0f)];
        }
        return string(str);
    }

    // ============ Version Control ============
    /**
     * @notice Return the version of DODOGasSavingPool
     * @return The current version is 1.0.1
     */
    function version() external pure returns (string memory) {
        return "GSP 1.0.1";
    }
}