// File: contracts/SMOLNftRewards.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import '@openzeppelin/contracts/access/Ownable.sol';
import '@openzeppelin/contracts/token/ERC721/IERC721.sol';
import './interfaces/ISMOLNftRewards.sol';
import './interfaces/ISmoltingInu.sol';

contract SMOLNftRewards is ISMOLNftRewards, Ownable {
  struct Reward {
    uint256 totalExcluded; // excluded reward
    uint256 totalRealised;
    uint256 lastClaim; // used for boosting logic
  }

  struct Share {
    uint256 amount;
    uint256 stakedTime;
  }

  IERC721 shareholderNFT;
  ISmoltingInu smol = ISmoltingInu(0x2bf6267c4997548d8de56087E5d48bDCCb877E77);
  uint256 public totalStakedUsers;
  uint256 public totalSharesDeposited; // will only be actual deposited tokens without handling any reflections or otherwise

  // amount of shares a user has
  mapping(address => Share) shares;
  // reward information per user
  mapping(address => Reward) public rewards;

  uint256 public totalRewards;
  uint256 public totalDistributed;
  uint256 public rewardsPerShare;

  uint256 private constant ACC_FACTOR = 10**36;

  event ClaimReward(address user);
  event DistributeReward(address indexed user);
  event DepositRewards(address indexed user, uint256 amountTokens);

  modifier onlyToken() {
    require(msg.sender == address(shareholderNFT), 'must be token contract');
    _;
  }

  constructor(address _shareholderNFT) {
    shareholderNFT = IERC721(_shareholderNFT);
  }

  function setShare(address shareholder, uint256 newBalance)
    external
    onlyToken
  {
    // _addShares and _removeShares takes the amount to add or remove respectively,
    // so we should handle the diff from the new balance when passing in the amounts
    // to these functions
    if (shares[shareholder].amount > newBalance) {
      _removeShares(shareholder, shares[shareholder].amount - newBalance);
    } else if (shares[shareholder].amount < newBalance) {
      _addShares(shareholder, newBalance - shares[shareholder].amount);
    }
  }

  function _addShares(address shareholder, uint256 amount) private {
    if (shares[shareholder].amount > 0) {
      _distributeReward(shareholder);
    }

    uint256 sharesBefore = shares[shareholder].amount;

    totalSharesDeposited += amount;
    shares[shareholder].amount += amount;
    shares[shareholder].stakedTime = block.timestamp;
    if (sharesBefore == 0 && shares[shareholder].amount > 0) {
      totalStakedUsers++;
    }
    rewards[shareholder].totalExcluded = getCumulativeRewards(
      shares[shareholder].amount
    );
  }

  function _removeShares(address shareholder, uint256 amount) private {
    require(
      shares[shareholder].amount > 0 &&
        (amount == 0 || amount <= shares[shareholder].amount),
      'you can only unstake if you have some staked'
    );
    _distributeReward(shareholder);

    uint256 removeAmount = amount == 0 ? shares[shareholder].amount : amount;

    totalSharesDeposited -= removeAmount;
    shares[shareholder].amount -= removeAmount;
    rewards[shareholder].totalExcluded = getCumulativeRewards(
      shares[shareholder].amount
    );
  }

  function depositRewards(uint256 _amount) external override onlyOwner {
    require(
      totalSharesDeposited > 0,
      'must be shares deposited to be rewarded rewards'
    );

    totalRewards += _amount;
    rewardsPerShare += (ACC_FACTOR * _amount) / totalSharesDeposited;
    smol.gameMint(address(this), _amount);
    emit DepositRewards(msg.sender, _amount);
  }

  function _distributeReward(address shareholder) internal {
    if (shares[shareholder].amount == 0) {
      return;
    }

    uint256 amount = getUnpaid(shareholder);

    rewards[shareholder].totalRealised += amount;
    rewards[shareholder].totalExcluded = getCumulativeRewards(
      shares[shareholder].amount
    );
    rewards[shareholder].lastClaim = block.timestamp;

    if (amount > 0) {
      totalDistributed += amount;
      smol.transfer(shareholder, amount);
      emit DistributeReward(shareholder);
    }
  }

  function claimReward() external override {
    _distributeReward(msg.sender);
    emit ClaimReward(msg.sender);
  }

  // returns the unpaid rewards
  function getUnpaid(address shareholder) public view returns (uint256) {
    if (shares[shareholder].amount == 0) {
      return 0;
    }

    uint256 earnedRewards = getCumulativeRewards(shares[shareholder].amount);
    uint256 rewardsExcluded = rewards[shareholder].totalExcluded;
    if (earnedRewards <= rewardsExcluded) {
      return 0;
    }

    return earnedRewards - rewardsExcluded;
  }

  function getCumulativeRewards(uint256 share) internal view returns (uint256) {
    return (share * rewardsPerShare) / ACC_FACTOR;
  }

  function getShares(address user) external view override returns (uint256) {
    return shares[user].amount;
  }

  function getShareholderNFT() external view returns (address) {
    return address(shareholderNFT);
  }

  function getSmolToken() external view returns (address) {
    return address(smol);
  }

  function setShareholderNFT(address _nft) external onlyOwner {
    shareholderNFT = IERC721(_nft);
  }

  function setSmolToken(address _token) external onlyOwner {
    smol = ISmoltingInu(_token);
  }
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^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() {
        _transferOwnership(_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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}

// File: contracts/interfaces/ISMOLNftRewards.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

interface ISMOLNftRewards {
  function claimReward() external;

  function depositRewards(uint256 _amount) external;

  function getShares(address wallet) external view returns (uint256);
}

// File: contracts/interfaces/ISmoltingInu.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import '@openzeppelin/contracts/interfaces/IERC20.sol';

/**
 * @dev SmoltingInu token interface
 */

interface ISmoltingInu is IERC20 {
  function gameMint(address _user, uint256 _amount) external;

  function gameBurn(address _user, uint256 _amount) external;

  function addPlayThrough(address _user, uint256 _amountWagered) external;
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^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 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) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

// File: @openzeppelin/contracts/interfaces/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (interfaces/IERC20.sol)

pragma solidity ^0.8.0;

import "../token/ERC20/IERC20.sol";

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)

pragma solidity ^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 `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, 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 `from` to `to` 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 from,
        address to,
        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);
}