// File: contracts/StakingPoolMigrator.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.6.12;

import '@openzeppelin/contracts/access/Ownable.sol';
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "./interfaces/IStakingPoolMigrator.sol";
import "./interfaces/ISwapPair.sol";
import "./interfaces/ISwapFactory.sol";

contract StakingPoolMigrator is IStakingPoolMigrator, Ownable {

    address public migrateFromFactory;
    address public migrateToFactory;
    address public stakingPools;
    address public txOrigin;
    uint256 public desiredLiquidity = uint256(-1);

    constructor(
        address _migrateFromFactory,
        address _migrateToFactory,
        address _stakingPools
    ) public {
        migrateFromFactory = _migrateFromFactory;
        migrateToFactory = _migrateToFactory;
        stakingPools = _stakingPools;
    }

    function setTxOrigin(address _txOrigin) external onlyOwner {
        txOrigin = _txOrigin;
    }

    function migrate(
        uint256 poolId,
        address oldToken,
        uint256 amount
    ) external override returns (address){
        require(tx.origin == txOrigin, "StakingPoolMigrator: Not from txOrigin defined.");
        require(amount > 0, "StakingPoolMigrator: Zero amount to migrate");
        address _stakingPools = stakingPools;

        require(msg.sender == _stakingPools, "StakingPoolMigrator: Not from StakingPools");
        ISwapPair oldPair = ISwapPair(oldToken);
        require(oldPair.factory() == migrateFromFactory, "StakingPoolMigrator: Not migrating from Uniswap Factory");

        address token0 = oldPair.token0();
        address token1 = oldPair.token1();

        ISwapFactory newFactory = ISwapFactory(migrateToFactory);
        ISwapPair newPair = ISwapPair(newFactory.getPair(token0, token1));
        require(newPair != ISwapPair(address(0)), "StakingPoolMigrator: Convergence pool hasn't been created");
        require(newPair.totalSupply() == 0, "StakingPoolMigrator: Not migrating to a fresh pool");
        require(newFactory.migrator() == address(this), "StakingPoolMigrator: new factory migrator not correct");
        require(amount == oldPair.balanceOf(_stakingPools), "StakingPoolMigrator: Not migrating all amounts from StakingPools");

        desiredLiquidity = amount;
        oldPair.transferFrom(_stakingPools, address(oldPair), amount);
        oldPair.burn(address(newPair));

        uint256 token0AmountMigrated = IERC20(token0).balanceOf(address(newPair));
        uint256 token1AmountMigrated = IERC20(token1).balanceOf(address(newPair));
        newPair.mint(_stakingPools);
        (uint112 reserve0, uint112 reserve1,) = newPair.getReserves();
        require(token0AmountMigrated == reserve0, "StakingPoolMigrator: migrated token0 amount not match with reserve0");
        require(token1AmountMigrated == reserve1, "StakingPoolMigrator: migrated token1 amount not match with reserve1");

        desiredLiquidity = uint256(-1);
        require(amount == newPair.balanceOf(address(_stakingPools)), "StakingPoolMigrator: migrated lp token balance must match");
        require(0 == oldPair.balanceOf(_stakingPools), "StakingPoolMigrator: There is remaining balance for old lp token in StakingPools");

        return address(newPair);
    }


}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../utils/Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: contracts/interfaces/IStakingPoolMigrator.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.6.12;

interface IStakingPoolMigrator {
    function migrate(
        uint256 poolId,
        address oldToken,
        uint256 amount
    ) external returns (address);
}

// File: contracts/interfaces/ISwapPair.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;

interface ISwapPair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}
// File: contracts/interfaces/ISwapFactory.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;

interface ISwapFactory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);
    function freezerSetter() external view returns (address);
    function migrator() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
    function setFreezerSetter(address) external;
    function setMigrator(address) external;
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}