DyDxAdapter.sol

// Copyright (C) 2020 Zerion Inc. <https://zerion.io>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
//
// SPDX-License-Identifier: LGPL-3.0-only

pragma solidity 0.7.3;
pragma experimental ABIEncoderV2;

import { Info, Wei, SoloMargin } from "../../interfaces/SoloMargin.sol";
import { ProtocolAdapter } from "../ProtocolAdapter.sol";

/**
 * @dev dYdX adapter abstract contract.
 * @dev Base contract for dYdX adapters.
 * @author Igor Sobolev <sobolev@zerion.io>
 */
abstract contract DyDxAdapter is ProtocolAdapter {
    address internal constant SOLO = 0x1E0447b19BB6EcFdAe1e4AE1694b0C3659614e4e;

    address internal constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    address internal constant SAI = 0x89d24A6b4CcB1B6fAA2625fE562bDD9a23260359;
    address internal constant USDC = 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48;
    address internal constant DAI = 0x6B175474E89094C44Da98b954EedeAC495271d0F;

    function getBalance(address token, address account) public override returns (int256) {
        Wei memory accountWei = SoloMargin(SOLO).getAccountWei(
            Info(account, 0),
            getMarketId(token)
        );

        return accountWei.sign ? int256(accountWei.value) : int256(-accountWei.value);
    }

    function getMarketId(address token) internal pure returns (uint256) {
        if (token == WETH) {
            return uint256(0);
        } else if (token == SAI) {
            return uint256(1);
        } else if (token == USDC) {
            return uint256(2);
        } else if (token == DAI) {
            return uint256(3);
        } else {
            return type(uint256).max;
        }
    }
}