// Contract: YFTEFarming_TetherswapLP
// Target function: function transferAnyERC20Tokens(
en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.0.0, only sets of type `address` (`AddressSet`) and `uint256`
 * (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            bytes32 lastvalue = set._values[lastIndex];

            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value)
        private
        view
        returns (bool)
    {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function _at(Set storage set, uint256 index)
        private
        view
        returns (bytes32)
    {
        require(
            set._values.length > index,
            "EnumerableSet: index out of bounds"
        );
        return set._values[index];
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value)
        internal
        returns (bool)
    {
        return _add(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value)
        internal
        returns (bool)
    {
        return _remove(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value)
        internal
        view
        returns (bool)
    {
        return _contains(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressSet storage set, uint256 index)
        internal
        view
        returns (address)
    {
        return address(uint256(_at(set._inner, index)));
    }

    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value)
        internal
        returns (bool)
    {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value)
        internal
        view
        returns (bool)
    {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintSet storage set, uint256 index)
        internal
        view
        returns (uint256)
    {
        return uint256(_at(set._inner, index));
    }
}

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address public owner;

    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor() {
        owner = msg.sender;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        require(newOwner != address(0));
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;
    }
}

interface Token {
    function transferFrom(
        address,
        address,
        uint256
    ) external returns (bool);

    function transfer(address, uint256) external returns (bool);
}

contract YFTEFarming_TetherswapLP is Ownable {
    using SafeMath for uint256;
    using EnumerableSet for EnumerableSet.AddressSet;

    event RewardsTransferred(address holder, uint256 amount);
    event RewardsDisbursed(uint256 amount);

    // Tetherswap ETH/YFTE LP token contract address
    address public constant LPtokenAddress =
        0x31b71356290289806CcBa638B0A6c79121a965E9;
    //YFTether token address
    address public constant tokenAddress =
        0x94F31aC896c9823D81cf9C2C93feCEeD4923218f;
    uint256 public constant withdrawFeePercentX100 = 50;
    uint256 public constant disburseAmount = 50e18;
    uint256 public constant disburseDuration = 7 days;

    uint256 public disbursePercentX100 = 10000;

    uint256 public lastDisburseTime;

    constructor() {
        lastDisburseTime = block.timestamp;
    }

    uint256 public totalClaimedRewards = 0;

    EnumerableSet.AddressSet private holders;

    mapping(address => uint256) public depositedTokens;
    mapping(address => uint256) public depositTime;
    mapping(address => uint256) public lastClaimedTime;
    mapping(address => uint256) public totalEarnedTokens;
    mapping(address => uint256) public lastDivPoints;

    uint256 public totalTokensDisbursed = 0;
    uint256 public contractBalance = 0;

    uint256 public totalDivPoints = 0;
    uint256 public totalTokens = 0;

    uint256 internal pointMultiplier = 1e18;

    function addContractBalance(uint256 amount) public onlyOwner {
        require(
            Token(tokenAddress).transferFrom(msg.sender, address(this), amount),
            "Cannot add balance!"
        );
        contractBalance = contractBalance.add(amount);
    }

    function updateAccount(address account) private {
        uint256 pendingDivs = getPendingDivs(account);
        if (pendingDivs > 0) {
            require(
                Token(tokenAddress).transfer(account, pendingDivs),
                "Could not transfer tokens."
            );
            totalEarnedTokens[account] = totalEarnedTokens[account].add(
                pendingDivs
            );
            totalClaimedRewards = totalClaimedRewards.add(pendingDivs);
            emit RewardsTransferred(account, pendingDivs);
        }
        lastClaimedTime[account] = block.timestamp;
        lastDivPoints[account] = totalDivPoints;
    }

    function getPendingDivs(address _holder) public view returns (uint256) {
        if (!holders.contains(_holder)) return 0;
        if (depositedTokens[_holder] == 0) return 0;

        uint256 newDivPoints = totalDivPoints.sub(lastDivPoints[_holder]);

        uint256 depositedAmount = depositedTokens[_holder];

        uint256 pendingDivs =
            depositedAmount.mul(newDivPoints).div(pointMultiplier);

        return pendingDivs;
    }

    function getNumberOfHolders() public view returns (uint256) {
        return holders.length();
    }

    function deposit(uint256 amountToDeposit) public {
        require(amountToDeposit > 0, "Cannot deposit 0 Tokens");

        updateAccount(msg.sender);

        require(
            Token(LPtokenAddress).transferFrom(
                msg.sender,
                address(this),
                amountToDeposit
            ),
            "Insufficient Token Allowance"
        );

        depositedTokens[msg.sender] = depositedTokens[msg.sender].add(
            amountToDeposit
        );
        totalTokens = totalTokens.add(amountToDeposit);

        if (!holders.contains(msg.sender)) {
            holders.add(msg.sender);
            depositTime[msg.sender] = block.timestamp;
        }
    }

    function withdraw(uint256 amountToWithdraw) public {
        require(
            depositedTokens[msg.sender] >= amountToWithdraw,
            "Invalid amount to withdraw"
        );

        updateAccount(msg.sender);

        uint256 fee = amountToWithdraw.mul(withdrawFeePercentX100).div(1e4);
        uint256 amountAfterFee = amountToWithdraw.sub(fee);

        require(
            Token(LPtokenAddress).transfer(owner, fee),
            "Could not transfer fee!"
        );

        require(
            Token(LPtokenAddress).transfer(msg.sender, amountAfterFee),
            "Could not transfer tokens."
        );

        depositedTokens[msg.sender] = depositedTokens[msg.sender].sub(
            amountToWithdraw
        );
        totalTokens = totalTokens.sub(amountToWithdraw);

        if (holders.contains(msg.sender) && depositedTokens[msg.sender] == 0) {
            holders.remove(msg.sender);
        }
    }

    function emergencyWithdraw(uint256 amountToWithdraw) public {
        require(
            depositedTokens[msg.sender] >= amountToWithdraw,
            "Invalid amount to withdraw"
        );

        lastClaimedTime[msg.sender] = block.timestamp;
        lastDivPoints[msg.sender] = totalDivPoints;

        uint256 fee = amountToWithdraw.mul(withdrawFeePercentX100).div(1e4);
        uint256 amountAfterFee = amountToWithdraw.sub(fee);

        require(
            Token(LPtokenAddress).transfer(owner, fee),
            "Could not transfer fee!"
        );

        require(
            Token(LPtokenAddress).transfer(msg.sender, amountAfterFee),
            "Could not transfer tokens."
        );

        depositedTokens[msg.sender] = depositedTokens[msg.sender].sub(
            amountToWithdraw
        );
        totalTokens = totalTokens.sub(amountToWithdraw);

        if (holders.contains(msg.sender) && depositedTokens[msg.sender] == 0) {
            holders.remove(msg.sender);
        }
    }

    function claim() public {
        updateAccount(msg.sender);
    }

    function distributeDivs(uint256 amount) private {
        if (totalTokens == 0) return;
        totalDivPoints = totalDivPoints.add(
            amount.mul(pointMultiplier).div(totalTokens)
        );
        emit RewardsDisbursed(amount);
    }

    function disburseTokens() public onlyOwner {
        uint256 amount = getPendingDisbursement();

        // uint contractBalance = Token(tokenAddress).balanceOf(address(this));

        if (contractBalance < amount) {
            amount = contractBalance;
        }
        if (amount == 0) return;
        distributeDivs(amount);
        contractBalance = contractBalance.sub(amount);
        lastDisburseTime = block.timestamp;
    }

    function getPendingDisbursement() public view returns (uint256) {
        uint256 timeDiff = block.timestamp.sub(lastDisburseTime);
        uint256 pendingDisburse =
            disburseAmount
                .mul(disbursePercentX100)
                .mul(timeDiff)
                .div(disburseDuration)
                .div(10000);
        return pendingDisburse;
    }

    function getDepositorsList(uint256 startIndex, uint256 endIndex)
        public
        view
        returns (
            address[] memory stakers,
            uint256[] memory stakingTimestamps,
            uint256[] memory lastClaimedTimeStamps,
            uint256[] memory stakedTokens
        )
    {
        require(startIndex < endIndex);

        uint256 length = endIndex.sub(startIndex);
        address[] memory _stakers = new address[](length);
        uint256[] memory _stakingTimestamps = new uint256[](length);
        uint256[] memory _lastClaimedTimeStamps = new uint256[](length);
        uint256[] memory _stakedTokens = new uint256[](length);

        for (uint256 i = startIndex; i < endIndex; i = i.add(1)) {
            address staker = holders.at(i);
            uint256 listIndex = i.sub(startIndex);
            _stakers[listIndex] = staker;
            _stakingTimestamps[listIndex] = depositTime[staker];
            _lastClaimedTimeStamps[listIndex] = lastClaimedTime[staker];
            _stakedTokens[listIndex] = depositedTokens[staker];
        }

        return (
            _stakers,
            _stakingTimestamps,
            _lastClaimedTimeStamps,
            _stakedTokens
        );
    }