// File: Farm01.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

// Ideally this contract should not be interacted with directly. Use our front end Dapp to create a farm
// to ensure the most effeicient amount of tokens are sent to the contract

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);
}


/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies in extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return _functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}


/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// helper methods for interacting with ERC20 tokens that do not consistently return true/false
library TransferHelper {
    function safeApprove(address token, address to, uint value) internal {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: APPROVE_FAILED');
    }

    function safeTransfer(address token, address to, uint value) internal {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FAILED');
    }

    function safeTransferFrom(address token, address from, address to, uint value) internal {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FROM_FAILED');
    }

}

interface IFarmFactory {
    function userEnteredFarm (address _user) external;
    function userLeftFarm (address _user) external;
}

contract Farm01 {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    /// @notice information stuct on each user than stakes LP tokens.
    struct UserInfo {
        uint256 amount;     // How many LP tokens the user has provided.
        uint256 rewardDebt; // Reward debt.
    }
    
    /// @notice all the settings for this farm in one struct
    struct FarmInfo {
        IERC20 lpToken;
        IERC20 rewardToken;
        uint256 startBlock;
        uint256 blockReward;
        uint256 bonusEndBlock;
        uint256 bonus;
        uint256 endBlock;
        uint256 lastRewardBlock;  // Last block number that reward distribution occurs.
        uint256 accRewardPerShare; // Accumulated Rewards per share, times 1e12
        uint256 farmableSupply; // set in init, total amount of tokens farmable
        uint256 numFarmers;
    }
    
    /// @notice farm type id. Useful for back-end systems to know how to read the contract (ABI) as we plan to launch multiple farm types
    uint256 public farmType = 1;

    IFarmFactory public factory;
    address public farmGenerator;

    FarmInfo public farmInfo;
    
    /// @notice information on each user than stakes LP tokens
    mapping (address => UserInfo) public userInfo;

    event Deposit(address indexed user, uint256 amount);
    event Withdraw(address indexed user, uint256 amount);
    event EmergencyWithdraw(address indexed user, uint256 amount);

    constructor(address _factory, address _farmGenerator) public {
        factory = IFarmFactory(_factory);
        farmGenerator = _farmGenerator;
    }
    
    /**
     * @notice initialize the farming contract. This is called only once upon farm creation and the FarmGenerator ensures the farm has the correct paramaters
     */
    function init (IERC20 _rewardToken, uint256 _amount, IERC20 _lpToken, uint256 _blockReward, uint256 _startBlock, uint256 _endBlock, uint256 _bonusEndBlock, uint256 _bonus) public {
        require(msg.sender == address(farmGenerator), 'FORBIDDEN');

        TransferHelper.safeTransferFrom(address(_rewardToken), msg.sender, address(this), _amount);
        farmInfo.rewardToken = _rewardToken;
        
        farmInfo.startBlock = _startBlock;
        farmInfo.blockReward = _blockReward;
        farmInfo.bonusEndBlock = _bonusEndBlock;
        farmInfo.bonus = _bonus;
        
        uint256 lastRewardBlock = block.number > _startBlock ? block.number : _startBlock;
        farmInfo.lpToken = _lpToken;
        farmInfo.lastRewardBlock = lastRewardBlock;
        farmInfo.accRewardPerShare = 0;
        
        farmInfo.endBlock = _endBlock;
        farmInfo.farmableSupply = _amount;
    }

    /**
     * @notice Gets the reward multiplier over the given _from_block until _to block
     * @param _from_block the start of the period to measure rewards for
     * @param _to the end of the period to measure rewards for
     * @return The weighted multiplier for the given period
     */
    function getMultiplier(uint256 _from_block, uint256 _to) public view returns (uint256) {
        uint256 _from = _from_block >= farmInfo.startBlock ? _from_block : farmInfo.startBlock;
        uint256 to = farmInfo.endBlock > _to ? _to : farmInfo.endBlock;
        if (to <= farmInfo.bonusEndBlock) {
            return to.sub(_from).mul(farmInfo.bonus);
        } else if (_from >= farmInfo.bonusEndBlock) {
            return to.sub(_from);
        } else {
            return farmInfo.bonusEndBlock.sub(_from).mul(farmInfo.bonus).add(
                to.sub(farmInfo.bonusEndBlock)
            );
        }
    }

    /**
     * @notice function to see accumulated balance of reward token for specified user
     * @param _user the user for whom unclaimed tokens will be shown
     * @return total amount of withdrawable reward tokens
     */
    function pendingReward(address _user) external view returns (uint256) {
        UserInfo storage user = userInfo[_user];
        uint256 accRewardPerShare = farmInfo.accRewardPerShare;
        uint256 lpSupply = farmInfo.lpToken.balanceOf(address(this));
        if (block.number > farmInfo.lastRewardBlock && lpSupply != 0) {
            uint256 multiplier = getMultiplier(farmInfo.lastRewardBlock, block.number);
            uint256 tokenReward = multiplier.mul(farmInfo.blockReward);
            accRewardPerShare = accRewardPerShare.add(tokenReward.mul(1e12).div(lpSupply));
        }
        return user.amount.mul(accRewardPerShare).div(1e12).sub(user.rewardDebt);
    }

    /**
     * @notice updates pool information to be up to date to the current block
     */
    function updatePool() public {
        if (block.number <= farmInfo.lastRewardBlock) {
            return;
        }
        uint256 lpSupply = farmInfo.lpToken.balanceOf(address(this));
        if (lpSupply == 0) {
            farmInfo.lastRewardBlock = block.number < farmInfo.endBlock ? block.number : farmInfo.endBlock;
            return;
        }
        uint256 multiplier = getMultiplier(farmInfo.lastRewardBlock, block.number);
        uint256 tokenReward = multiplier.mul(farmInfo.blockReward);
        farmInfo.accRewardPerShare = farmInfo.accRewardPerShare.add(tokenReward.mul(1e12).div(lpSupply));
        farmInfo.lastRewardBlock = block.number < farmInfo.endBlock ? block.number : farmInfo.endBlock;
    }
    
    /**
     * @notice deposit LP token function for msg.sender
     * @param _amount the total deposit amount
     */
    function deposit(uint256 _amount) public {
        UserInfo storage user = userInfo[msg.sender];
        updatePool();
        if (user.amount > 0) {
            uint256 pending = user.amount.mul(farmInfo.accRewardPerShare).div(1e12).sub(user.rewardDebt);
            safeRewardTransfer(msg.sender, pending);
        }
        if (user.amount == 0 && _amount > 0) {
            factory.userEnteredFarm(msg.sender);
            farmInfo.numFarmers++;
        }
        farmInfo.lpToken.safeTransferFrom(address(msg.sender), address(this), _amount);
        user.amount = user.amount.add(_amount);
        user.rewardDebt = user.amount.mul(farmInfo.accRewardPerShare).div(1e12);
        emit Deposit(msg.sender, _amount);
    }

    /**
     * @notice withdraw LP token function for msg.sender
     * @param _amount the total withdrawable amount
     */
    function withdraw(uint256 _amount) public {
        UserInfo storage user = userInfo[msg.sender];
        require(user.amount >= _amount, "INSUFFICIENT");
        updatePool();
        if (user.amount == _amount && _amount > 0) {
            factory.userLeftFarm(msg.sender);
            farmInfo.numFarmers--;
        }
        uint256 pending = user.amount.mul(farmInfo.accRewardPerShare).div(1e12).sub(user.rewardDebt);
        safeRewardTransfer(msg.sender, pending);
        user.amount = user.amount.sub(_amount);
        user.rewardDebt = user.amount.mul(farmInfo.accRewardPerShare).div(1e12);
        farmInfo.lpToken.safeTransfer(address(msg.sender), _amount);
        emit Withdraw(msg.sender, _amount);
    }

    /**
     * @notice emergency functoin to withdraw LP tokens and forego harvest rewards. Important to protect users LP tokens
     */
    function emergencyWithdraw() public {
        UserInfo storage user = userInfo[msg.sender];
        farmInfo.lpToken.safeTransfer(address(msg.sender), user.amount);
        emit EmergencyWithdraw(msg.sender, user.amount);
        if (user.amount > 0) {
            factory.userLeftFarm(msg.sender);
            farmInfo.numFarmers--;
        }
        user.amount = 0;
        user.rewardDebt = 0;
    }

    /**
     * @notice Safe reward transfer function, just in case a rounding error causes pool to not have enough reward tokens
     * @param _to the user address to transfer tokens to
     * @param _amount the total amount of tokens to transfer
     */
    function safeRewardTransfer(address _to, uint256 _amount) internal {
        uint256 rewardBal = farmInfo.rewardToken.balanceOf(address(this));
        if (_amount > rewardBal) {
            farmInfo.rewardToken.transfer(_to, rewardBal);
        } else {
            farmInfo.rewardToken.transfer(_to, _amount);
        }
    }
}
// File: FarmGenerator.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "./Farm01.sol";

/*
 * @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;
    }
}

/**
 * @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.
 */
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 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;
    }
}

interface IERCBurn {
    function burn(uint256 _amount) external;
    function approve(address spender, uint256 amount) external returns (bool);
    function allowance(address owner, address spender) external returns (uint256);
}

interface FarmFactory {
    function registerFarm (address _farmAddress) external;
}

interface IUniFactory {
    function getPair(address tokenA, address tokenB) external view returns (address);
}

interface IUniswapV2Pair {
    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;
}

contract FarmGenerator01 is Ownable {
    using SafeMath for uint256;
    
    FarmFactory public factory;
    
    struct FarmParameters {
        uint256 bonusBlocks;
        uint256 totalBonusReward;
        uint256 numBlocks;
        uint256 endBlock;
        uint256 requiredAmount;
    }
    
    constructor(FarmFactory _factory) public {
        factory = _factory;
    }
    
    /**
     * @notice Determine the endBlock based on inputs. Used on the front end to show the exact settings the Farm contract will be deployed with
     */
    function determineEndBlock (uint256 _amount, uint256 _blockReward, uint256 _startBlock, uint256 _bonusEndBlock, uint256 _bonus) public pure returns (uint256, uint256) {
        FarmParameters memory params;
        params.bonusBlocks = _bonusEndBlock.sub(_startBlock);
        params.totalBonusReward = params.bonusBlocks.mul(_bonus).mul(_blockReward);
        params.numBlocks = _amount.sub(params.totalBonusReward).div(_blockReward);
        params.endBlock = params.numBlocks.add(params.bonusBlocks).add(_startBlock);
        
        uint256 nonBonusBlocks = params.endBlock.sub(_bonusEndBlock);
        uint256 effectiveBlocks = params.bonusBlocks.mul(_bonus).add(nonBonusBlocks);
        uint256 requiredAmount = _blockReward.mul(effectiveBlocks);
        return (params.endBlock, requiredAmount);
    }
    
    /**
     * @notice Determine the blockReward based on inputs specifying an end date. Used on the front end to show the exact settings the Farm contract will be deployed with
     */
    function determineBlockReward (uint256 _amount, uint256 _startBlock, uint256 _bonusEndBlock, uint256 _bonus, uint256 _endBlock) public pure returns (uint256, uint256) {
        uint256 bonusBlocks = _bonusEndBlock.sub(_startBlock);
        uint256 nonBonusBlocks = _endBlock.sub(_bonusEndBlock);
        uint256 effectiveBlocks = bonusBlocks.mul(_bonus).add(nonBonusBlocks);
        uint256 blockReward = _amount.div(effectiveBlocks);
        uint256 requiredAmount = blockReward.mul(effectiveBlocks);
        return (blockReward, requiredAmount);
    }
    
    /**
     * @notice Creates a new Farm contract and registers it in the 
     * .sol. All farming rewards are locked in the Farm Contract
     */
    function createFarm (IERC20 _rewardToken, uint256 _amount, IERC20 _lpToken,IUniFactory _swapFactory, uint256 _blockReward, uint256 _startBlock, uint256 _bonusEndBlock, uint256 _bonus) public onlyOwner returns (address){
        require(_startBlock > block.number, 'START'); // ideally at least 24 hours more to give farmers time
        require(_bonus > 0, 'BONUS');
        require(address(_rewardToken) != address(0), 'TOKEN');
        require(_blockReward > 1000, 'BR'); // minimum 1000 divisibility per block reward
        IUniFactory swapFactory = _swapFactory;
        // ensure this pair is on swapFactory by querying the factory
        IUniswapV2Pair lpair = IUniswapV2Pair(address(_lpToken));
        address factoryPairAddress = swapFactory.getPair(lpair.token0(), lpair.token1());
        require(factoryPairAddress == address(_lpToken), 'This pair is not on _swapFactory exchange');
        
        FarmParameters memory params;
        (params.endBlock, params.requiredAmount) = determineEndBlock(_amount, _blockReward, _startBlock, _bonusEndBlock, _bonus);
        
        TransferHelper.safeTransferFrom(address(_rewardToken), address(msg.sender), address(this), params.requiredAmount);
        Farm01 newFarm = new Farm01(address(factory), address(this));
        TransferHelper.safeApprove(address(_rewardToken), address(newFarm), params.requiredAmount);
        newFarm.init(_rewardToken, params.requiredAmount, _lpToken, _blockReward, _startBlock, params.endBlock, _bonusEndBlock, _bonus);
        
        factory.registerFarm(address(newFarm));
        return (address(newFarm));
    }
    
}