// SPDX-FileCopyrightText: © 2023 Dai Foundation <www.daifoundation.org>
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

pragma solidity ^0.8.21;

interface VatLike {
    function hope(address) external;
}

interface GemLike {
    function balanceOf(address) external view returns (uint256);
    function approve(address, uint256) external;
    function transfer(address, uint256) external;
}

interface StakingRewardsLike {
    function rewardsToken() external view returns (GemLike);
    function stake(uint256, uint16) external;
    function withdraw(uint256) external;
    function getReward() external;
}

contract LockstakeUrn {
    // --- immutables ---

    address immutable public engine;
    GemLike immutable public lsmkr;
    VatLike immutable public vat;

    // --- modifiers ---

    modifier isEngine {
        require(msg.sender == engine, "LockstakeUrn/not-engine");
        _;
    }

    // --- constructor & init ---

    constructor(address vat_, address lsmkr_) {
        engine = msg.sender;
        vat = VatLike(vat_);
        lsmkr = GemLike(lsmkr_);
    }

    function init() external isEngine {
        vat.hope(msg.sender);
        lsmkr.approve(msg.sender, type(uint256).max);
    }

    // --- staking functions ---

    function stake(address farm, uint256 wad, uint16 ref) external isEngine {
        lsmkr.approve(farm, wad);
        StakingRewardsLike(farm).stake(wad, ref);
    }

    function withdraw(address farm, uint256 wad) external isEngine {
        StakingRewardsLike(farm).withdraw(wad);
    }

    function getReward(address farm, address to) external isEngine returns (uint256 amt) {
        StakingRewardsLike(farm).getReward();
        GemLike rewardsToken = StakingRewardsLike(farm).rewardsToken();
        amt = rewardsToken.balanceOf(address(this));
        rewardsToken.transfer(to, amt);
    }
}

{
  "remappings": [
    "dss-interfaces/=lib/token-tests/lib/dss-test/lib/dss-interfaces/src/",
    "dss-test/=lib/token-tests/lib/dss-test/src/",
    "forge-std/=lib/token-tests/lib/dss-test/lib/forge-std/src/",
    "token-tests/=lib/token-tests/src/"
  ],
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "metadata": {
    "useLiteralContent": false,
    "bytecodeHash": "ipfs",
    "appendCBOR": true
  },
  "outputSelection": {
    "*": {
      "*": [
        "evm.bytecode",
        "evm.deployedBytecode",
        "devdoc",
        "userdoc",
        "metadata",
        "abi"
      ]
    }
  },
  "evmVersion": "paris",
  "viaIR": false,
  "libraries": {}
}

[{"inputs":[{"internalType":"address","name":"vat_","type":"address"},{"internalType":"address","name":"lsmkr_","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"engine","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"farm","type":"address"},{"internalType":"address","name":"to","type":"address"}],"name":"getReward","outputs":[{"internalType":"uint256","name":"amt","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"init","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"lsmkr","outputs":[{"internalType":"contract GemLike","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"farm","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"},{"internalType":"uint16","name":"ref","type":"uint16"}],"name":"stake","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"vat","outputs":[{"internalType":"contract VatLike","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"farm","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"withdraw","outputs":[],"stateMutability":"nonpayable","type":"function"}]