// File: contracts/Randomizer.sol



// SPDX-License-Identifier: MIT
// An example of a consumer contract that also owns and manages the subscription
pragma solidity ^0.8.7;
pragma abicoder v2;

import "@chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol";
import "@chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol";
import "@chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "./interfaces/IUniswapV2Router.sol";
import "./interfaces/IWETH.sol";

contract Randomizer is VRFConsumerBaseV2 {
  VRFCoordinatorV2Interface COORDINATOR;
  LinkTokenInterface LINKTOKEN;

  address vrfCoordinator = 0x271682DEB8C4E0901D1a1550aD2e64D568E69909;
  address link_token_contract = 0x514910771AF9Ca656af840dff83E8264EcF986CA;
  bytes32 keyHash = 0x8af398995b04c28e9951adb9721ef74c74f93e6a478f39e7e0777be13527e7ef;
  uint32 callbackGasLimit = 2500000;
  uint16 requestConfirmations = 3;
  uint32 numWords =  100;

  // Storage parameters
  uint256[] private s_randomWords;
  uint256 public s_requestId;
  uint64 public s_subscriptionId;
  address s_owner;

  mapping(address => bool) gameContracts;

  uint256 wordsThreshold = 25;
  bool requestPending;
  
  address private constant UNISWAP_V2_ROUTER = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
  address private constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
  address public constant LINK = 0x514910771AF9Ca656af840dff83E8264EcF986CA;
  uint256 public swapThreshold = 10000000000000000;

  constructor() VRFConsumerBaseV2(vrfCoordinator) {
    COORDINATOR = VRFCoordinatorV2Interface(vrfCoordinator);
    LINKTOKEN = LinkTokenInterface(link_token_contract);
    s_owner = msg.sender;
    //Create a new subscription when you deploy the contract.
    createNewSubscription();
    gameContracts[address(this)] = true;
  }

  receive() external payable {}

  modifier onlyGames() {
    require(gameContracts[msg.sender], "only game contracts allowed");
    _;
  }

  // Assumes the subscription is funded sufficiently.
  function requestRandomWords() public onlyGames {
    // Will revert if subscription is not set and funded.
    s_requestId = COORDINATOR.requestRandomWords(
      keyHash,
      s_subscriptionId,
      requestConfirmations,
      callbackGasLimit,
      numWords
    );
  }

  function fulfillRandomWords(
    uint256, /* requestId */
    uint256[] memory randomWords
  ) internal override {
    s_randomWords = randomWords;
    requestPending = false;
  }

  function getRandomWords(uint256 number) external onlyGames returns (uint256[] memory ranWords) {
    ranWords = new uint256[](number);
    for (uint i = 0; i < number; i++) {
      uint256 curIndex = s_randomWords.length-1;
      ranWords[i] = s_randomWords[curIndex];
      s_randomWords.pop();
    }

    uint256 remainingWords = s_randomWords.length;
    if(remainingWords < wordsThreshold && !requestPending) {
      swapAndTopLink(); 
      requestRandomWords(); 
      requestPending = true;
    }
  }

  function getRemainingWords() external view onlyGames returns (uint256) {
    return s_randomWords.length;
  }

  // Create a new subscription when the contract is initially deployed.
  function createNewSubscription() private onlyOwner {
    s_subscriptionId = COORDINATOR.createSubscription();
    // Add this contract as a consumer of its own subscription.
    COORDINATOR.addConsumer(s_subscriptionId, address(this));
  }

  function swapAndTopLink() public onlyGames {
    uint256 amountIn = address(this).balance;
    if(amountIn < swapThreshold) {
      return;
    }

    IWETH(WETH).deposit{value: amountIn}();
    swap(WETH, LINK, amountIn, 0, address(this));

    uint256 amountOut = LINKTOKEN.balanceOf(address(this));
    LINKTOKEN.transferAndCall(address(COORDINATOR), amountOut, abi.encode(s_subscriptionId));
  }

  function swap(address _tokenIn, address _tokenOut, uint256 _amountIn, uint256 _amountOutMin, address _to) internal {
    IERC20(WETH).approve(UNISWAP_V2_ROUTER, _amountIn);

    address[] memory path;
    path = new address[](2);
    path[0] = _tokenIn;
    path[1] = _tokenOut;

    IUniswapV2Router(UNISWAP_V2_ROUTER).swapExactTokensForTokens(_amountIn, _amountOutMin, path, _to, block.timestamp);
  }

  // Assumes this contract owns link.
  // 1000000000000000000 = 1 LINK
  function topUpSubscription(uint256 amount) external onlyOwner {
    LINKTOKEN.transferAndCall(address(COORDINATOR), amount, abi.encode(s_subscriptionId));
  }

  function addConsumer(address consumerAddress) external onlyOwner {
    // Add a consumer contract to the subscription.
    COORDINATOR.addConsumer(s_subscriptionId, consumerAddress);
  }

  function removeConsumer(address consumerAddress) external onlyOwner {
    // Remove a consumer contract from the subscription.
    COORDINATOR.removeConsumer(s_subscriptionId, consumerAddress);
  }

  function cancelSubscription(address receivingWallet) external onlyOwner {
    // Cancel the subscription and send the remaining LINK to a wallet address.
    COORDINATOR.cancelSubscription(s_subscriptionId, receivingWallet);
    s_subscriptionId = 0;
  }

  // Transfer this contract's funds to an address.
  // 1000000000000000000 = 1 LINK
  function withdraw(uint256 amount, address to) external onlyOwner {
    LINKTOKEN.transfer(to, amount);
  }

  function rescueETH() external onlyOwner {
    uint256 amount = address(this).balance;
    payable(s_owner).transfer(amount);
  }

  function rescueToken(address _token) external onlyOwner {
    uint256 amount = IERC20(_token).balanceOf(address(this));
    IERC20(_token).transfer(s_owner, amount);
  }

  function setGameContract(address _contract, bool flag)external onlyOwner {
    gameContracts[_contract] = flag;
  }

  function setCallbackGas(uint32 _gas) external onlyOwner {
    callbackGasLimit = _gas;
  }

  function setNumWords(uint32 _numWords) external onlyOwner {
    numWords = _numWords;
  }

  function setSwapThreshold(uint256 _threshold) external onlyOwner {
    swapThreshold = _threshold;
  }

  function setWordsThreshold(uint256 _threshold) external onlyOwner {
    wordsThreshold = _threshold;
  }

  modifier onlyOwner() {
    require(msg.sender == s_owner);
    _;
  }
}


// File: contracts/interfaces/IWETH.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.16;

interface IWETH {
    function deposit() external payable;
    function transfer(address to, uint value) external returns (bool);
    function withdraw(uint) external;
}
// File: contracts/interfaces/IUniswapV2Router.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;

interface IUniswapV2Router {
  function getAmountsOut(uint256 amountIn, address[] memory path)
    external
    view
    returns (uint256[] memory amounts);
  
  function swapExactTokensForTokens(
  
    //amount of tokens we are sending in
    uint256 amountIn,
    //the minimum amount of tokens we want out of the trade
    uint256 amountOutMin,
    //list of token addresses we are going to trade in.  this is necessary to calculate amounts
    address[] calldata path,
    //this is the address we are going to send the output tokens to
    address to,
    //the last time that the trade is valid for
    uint256 deadline
  ) external returns (uint256[] memory amounts);
}


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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 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);
}

// File: @chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol



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

/** ****************************************************************************
 * @notice Interface for contracts using VRF randomness
 * *****************************************************************************
 * @dev PURPOSE
 *
 * @dev Reggie the Random Oracle (not his real job) wants to provide randomness
 * @dev to Vera the verifier in such a way that Vera can be sure he's not
 * @dev making his output up to suit himself. Reggie provides Vera a public key
 * @dev to which he knows the secret key. Each time Vera provides a seed to
 * @dev Reggie, he gives back a value which is computed completely
 * @dev deterministically from the seed and the secret key.
 *
 * @dev Reggie provides a proof by which Vera can verify that the output was
 * @dev correctly computed once Reggie tells it to her, but without that proof,
 * @dev the output is indistinguishable to her from a uniform random sample
 * @dev from the output space.
 *
 * @dev The purpose of this contract is to make it easy for unrelated contracts
 * @dev to talk to Vera the verifier about the work Reggie is doing, to provide
 * @dev simple access to a verifiable source of randomness. It ensures 2 things:
 * @dev 1. The fulfillment came from the VRFCoordinator
 * @dev 2. The consumer contract implements fulfillRandomWords.
 * *****************************************************************************
 * @dev USAGE
 *
 * @dev Calling contracts must inherit from VRFConsumerBase, and can
 * @dev initialize VRFConsumerBase's attributes in their constructor as
 * @dev shown:
 *
 * @dev   contract VRFConsumer {
 * @dev     constructor(<other arguments>, address _vrfCoordinator, address _link)
 * @dev       VRFConsumerBase(_vrfCoordinator) public {
 * @dev         <initialization with other arguments goes here>
 * @dev       }
 * @dev   }
 *
 * @dev The oracle will have given you an ID for the VRF keypair they have
 * @dev committed to (let's call it keyHash). Create subscription, fund it
 * @dev and your consumer contract as a consumer of it (see VRFCoordinatorInterface
 * @dev subscription management functions).
 * @dev Call requestRandomWords(keyHash, subId, minimumRequestConfirmations,
 * @dev callbackGasLimit, numWords),
 * @dev see (VRFCoordinatorInterface for a description of the arguments).
 *
 * @dev Once the VRFCoordinator has received and validated the oracle's response
 * @dev to your request, it will call your contract's fulfillRandomWords method.
 *
 * @dev The randomness argument to fulfillRandomWords is a set of random words
 * @dev generated from your requestId and the blockHash of the request.
 *
 * @dev If your contract could have concurrent requests open, you can use the
 * @dev requestId returned from requestRandomWords to track which response is associated
 * @dev with which randomness request.
 * @dev See "SECURITY CONSIDERATIONS" for principles to keep in mind,
 * @dev if your contract could have multiple requests in flight simultaneously.
 *
 * @dev Colliding `requestId`s are cryptographically impossible as long as seeds
 * @dev differ.
 *
 * *****************************************************************************
 * @dev SECURITY CONSIDERATIONS
 *
 * @dev A method with the ability to call your fulfillRandomness method directly
 * @dev could spoof a VRF response with any random value, so it's critical that
 * @dev it cannot be directly called by anything other than this base contract
 * @dev (specifically, by the VRFConsumerBase.rawFulfillRandomness method).
 *
 * @dev For your users to trust that your contract's random behavior is free
 * @dev from malicious interference, it's best if you can write it so that all
 * @dev behaviors implied by a VRF response are executed *during* your
 * @dev fulfillRandomness method. If your contract must store the response (or
 * @dev anything derived from it) and use it later, you must ensure that any
 * @dev user-significant behavior which depends on that stored value cannot be
 * @dev manipulated by a subsequent VRF request.
 *
 * @dev Similarly, both miners and the VRF oracle itself have some influence
 * @dev over the order in which VRF responses appear on the blockchain, so if
 * @dev your contract could have multiple VRF requests in flight simultaneously,
 * @dev you must ensure that the order in which the VRF responses arrive cannot
 * @dev be used to manipulate your contract's user-significant behavior.
 *
 * @dev Since the block hash of the block which contains the requestRandomness
 * @dev call is mixed into the input to the VRF *last*, a sufficiently powerful
 * @dev miner could, in principle, fork the blockchain to evict the block
 * @dev containing the request, forcing the request to be included in a
 * @dev different block with a different hash, and therefore a different input
 * @dev to the VRF. However, such an attack would incur a substantial economic
 * @dev cost. This cost scales with the number of blocks the VRF oracle waits
 * @dev until it calls responds to a request. It is for this reason that
 * @dev that you can signal to an oracle you'd like them to wait longer before
 * @dev responding to the request (however this is not enforced in the contract
 * @dev and so remains effective only in the case of unmodified oracle software).
 */
abstract contract VRFConsumerBaseV2 {
  error OnlyCoordinatorCanFulfill(address have, address want);
  address private immutable vrfCoordinator;

  /**
   * @param _vrfCoordinator address of VRFCoordinator contract
   */
  constructor(address _vrfCoordinator) {
    vrfCoordinator = _vrfCoordinator;
  }

  /**
   * @notice fulfillRandomness handles the VRF response. Your contract must
   * @notice implement it. See "SECURITY CONSIDERATIONS" above for important
   * @notice principles to keep in mind when implementing your fulfillRandomness
   * @notice method.
   *
   * @dev VRFConsumerBaseV2 expects its subcontracts to have a method with this
   * @dev signature, and will call it once it has verified the proof
   * @dev associated with the randomness. (It is triggered via a call to
   * @dev rawFulfillRandomness, below.)
   *
   * @param requestId The Id initially returned by requestRandomness
   * @param randomWords the VRF output expanded to the requested number of words
   */
  function fulfillRandomWords(uint256 requestId, uint256[] memory randomWords) internal virtual;

  // rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF
  // proof. rawFulfillRandomness then calls fulfillRandomness, after validating
  // the origin of the call
  function rawFulfillRandomWords(uint256 requestId, uint256[] memory randomWords) external {
    if (msg.sender != vrfCoordinator) {
      revert OnlyCoordinatorCanFulfill(msg.sender, vrfCoordinator);
    }
    fulfillRandomWords(requestId, randomWords);
  }
}

// File: @chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface VRFCoordinatorV2Interface {
  /**
   * @notice Get configuration relevant for making requests
   * @return minimumRequestConfirmations global min for request confirmations
   * @return maxGasLimit global max for request gas limit
   * @return s_provingKeyHashes list of registered key hashes
   */
  function getRequestConfig()
    external
    view
    returns (
      uint16,
      uint32,
      bytes32[] memory
    );

  /**
   * @notice Request a set of random words.
   * @param keyHash - Corresponds to a particular oracle job which uses
   * that key for generating the VRF proof. Different keyHash's have different gas price
   * ceilings, so you can select a specific one to bound your maximum per request cost.
   * @param subId  - The ID of the VRF subscription. Must be funded
   * with the minimum subscription balance required for the selected keyHash.
   * @param minimumRequestConfirmations - How many blocks you'd like the
   * oracle to wait before responding to the request. See SECURITY CONSIDERATIONS
   * for why you may want to request more. The acceptable range is
   * [minimumRequestBlockConfirmations, 200].
   * @param callbackGasLimit - How much gas you'd like to receive in your
   * fulfillRandomWords callback. Note that gasleft() inside fulfillRandomWords
   * may be slightly less than this amount because of gas used calling the function
   * (argument decoding etc.), so you may need to request slightly more than you expect
   * to have inside fulfillRandomWords. The acceptable range is
   * [0, maxGasLimit]
   * @param numWords - The number of uint256 random values you'd like to receive
   * in your fulfillRandomWords callback. Note these numbers are expanded in a
   * secure way by the VRFCoordinator from a single random value supplied by the oracle.
   * @return requestId - A unique identifier of the request. Can be used to match
   * a request to a response in fulfillRandomWords.
   */
  function requestRandomWords(
    bytes32 keyHash,
    uint64 subId,
    uint16 minimumRequestConfirmations,
    uint32 callbackGasLimit,
    uint32 numWords
  ) external returns (uint256 requestId);

  /**
   * @notice Create a VRF subscription.
   * @return subId - A unique subscription id.
   * @dev You can manage the consumer set dynamically with addConsumer/removeConsumer.
   * @dev Note to fund the subscription, use transferAndCall. For example
   * @dev  LINKTOKEN.transferAndCall(
   * @dev    address(COORDINATOR),
   * @dev    amount,
   * @dev    abi.encode(subId));
   */
  function createSubscription() external returns (uint64 subId);

  /**
   * @notice Get a VRF subscription.
   * @param subId - ID of the subscription
   * @return balance - LINK balance of the subscription in juels.
   * @return reqCount - number of requests for this subscription, determines fee tier.
   * @return owner - owner of the subscription.
   * @return consumers - list of consumer address which are able to use this subscription.
   */
  function getSubscription(uint64 subId)
    external
    view
    returns (
      uint96 balance,
      uint64 reqCount,
      address owner,
      address[] memory consumers
    );

  /**
   * @notice Request subscription owner transfer.
   * @param subId - ID of the subscription
   * @param newOwner - proposed new owner of the subscription
   */
  function requestSubscriptionOwnerTransfer(uint64 subId, address newOwner) external;

  /**
   * @notice Request subscription owner transfer.
   * @param subId - ID of the subscription
   * @dev will revert if original owner of subId has
   * not requested that msg.sender become the new owner.
   */
  function acceptSubscriptionOwnerTransfer(uint64 subId) external;

  /**
   * @notice Add a consumer to a VRF subscription.
   * @param subId - ID of the subscription
   * @param consumer - New consumer which can use the subscription
   */
  function addConsumer(uint64 subId, address consumer) external;

  /**
   * @notice Remove a consumer from a VRF subscription.
   * @param subId - ID of the subscription
   * @param consumer - Consumer to remove from the subscription
   */
  function removeConsumer(uint64 subId, address consumer) external;

  /**
   * @notice Cancel a subscription
   * @param subId - ID of the subscription
   * @param to - Where to send the remaining LINK to
   */
  function cancelSubscription(uint64 subId, address to) external;
}

// File: @chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface LinkTokenInterface {
  function allowance(address owner, address spender) external view returns (uint256 remaining);

  function approve(address spender, uint256 value) external returns (bool success);

  function balanceOf(address owner) external view returns (uint256 balance);

  function decimals() external view returns (uint8 decimalPlaces);

  function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);

  function increaseApproval(address spender, uint256 subtractedValue) external;

  function name() external view returns (string memory tokenName);

  function symbol() external view returns (string memory tokenSymbol);

  function totalSupply() external view returns (uint256 totalTokensIssued);

  function transfer(address to, uint256 value) external returns (bool success);

  function transferAndCall(
    address to,
    uint256 value,
    bytes calldata data
  ) external returns (bool success);

  function transferFrom(
    address from,
    address to,
    uint256 value
  ) external returns (bool success);
}