// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity =0.7.6;
pragma abicoder v2;

// TODO: change to import from @airdao/astra-cl-core
import '@airdao/astra-cl-core/contracts/libraries/LowGasSafeMath.sol';
// TODO: change to import from @airdao/astradex
import './interfaces/classic/IAstraPair.sol';

import './interfaces/INonfungiblePositionManager.sol';

import './libraries/TransferHelper.sol';

import './interfaces/ICLMigrator.sol';
import './base/PeripheryImmutableState.sol';
import './base/Multicall.sol';
import './base/SelfPermit.sol';
import './interfaces/external/ISAMB.sol';
import './base/PoolInitializer.sol';

/// @title AstraDEX CL Migrator
contract CLMigrator is ICLMigrator, PeripheryImmutableState, PoolInitializer, Multicall, SelfPermit {
    using LowGasSafeMath for uint256;

    address public immutable nonfungiblePositionManager;

    constructor(
        address _factory,
        address _SAMB,
        address _nonfungiblePositionManager
    ) PeripheryImmutableState(_factory, _SAMB) {
        nonfungiblePositionManager = _nonfungiblePositionManager;
    }

    receive() external payable {
        require(msg.sender == SAMB, 'Not SAMB');
    }

    function migrate(MigrateParams calldata params) external override {
        require(params.percentageToMigrate > 0, 'Percentage too small');
        require(params.percentageToMigrate <= 100, 'Percentage too large');

        // burn classic liquidity to this address
        IAstraPair(params.pair).transferFrom(msg.sender, params.pair, params.liquidityToMigrate);
        (uint256 amount0Classic, uint256 amount1Classic) = IAstraPair(params.pair).burn(address(this));

        // calculate the amounts to migrate to CL
        uint256 amount0ClassicToMigrate = amount0Classic.mul(params.percentageToMigrate) / 100;
        uint256 amount1ClassicToMigrate = amount1Classic.mul(params.percentageToMigrate) / 100;

        // approve the position manager up to the maximum token amounts
        TransferHelper.safeApprove(params.token0, nonfungiblePositionManager, amount0ClassicToMigrate);
        TransferHelper.safeApprove(params.token1, nonfungiblePositionManager, amount1ClassicToMigrate);

        // mint CL position
        (, , uint256 amount0CL, uint256 amount1CL) = INonfungiblePositionManager(nonfungiblePositionManager).mint(
            INonfungiblePositionManager.MintParams({
                token0: params.token0,
                token1: params.token1,
                fee: params.fee,
                tickLower: params.tickLower,
                tickUpper: params.tickUpper,
                amount0Desired: amount0ClassicToMigrate,
                amount1Desired: amount1ClassicToMigrate,
                amount0Min: params.amount0Min,
                amount1Min: params.amount1Min,
                recipient: params.recipient,
                deadline: params.deadline
            })
        );

        // if necessary, clear allowance and refund dust
        if (amount0CL < amount0Classic) {
            if (amount0CL < amount0ClassicToMigrate) {
                TransferHelper.safeApprove(params.token0, nonfungiblePositionManager, 0);
            }

            uint256 refund0 = amount0Classic - amount0CL;
            if (params.refundAsAMB && params.token0 == SAMB) {
                ISAMB(SAMB).withdraw(refund0);
                TransferHelper.safeTransferAMB(msg.sender, refund0);
            } else {
                TransferHelper.safeTransfer(params.token0, msg.sender, refund0);
            }
        }
        if (amount1CL < amount1Classic) {
            if (amount1CL < amount1ClassicToMigrate) {
                TransferHelper.safeApprove(params.token1, nonfungiblePositionManager, 0);
            }

            uint256 refund1 = amount1Classic - amount1CL;
            if (params.refundAsAMB && params.token1 == SAMB) {
                ISAMB(SAMB).withdraw(refund1);
                TransferHelper.safeTransferAMB(msg.sender, refund1);
            } else {
                TransferHelper.safeTransfer(params.token1, msg.sender, refund1);
            }
        }
    }
}