Feature/improve docs

README.md

@@ -31,7 +31,17 @@ Navigate to each directory and follow the instructions in their respective READM
 
 ## Solution Overview
 
-<img src="./solution-diagram.png" alt="Solution" width="100%"/>
+<img src="./solution-diagram.png" alt="Solution" width="100%"/><br>
+
+Code references:
+
+1. Predict game result: [PredictionGame.sol#L116](./contracts/contracts/SportsPredictionGame.sol#L116)
+2. Check for finished games: [PredictionGame.sol#379](./contracts/contracts/SportsPredictionGame.sol#L379)
+3. Request game result: [ResultsConsumer.sol#L65](./contracts/contracts/ResultsConsumer.sol#L65)
+4. Fetch game result: [sports-api.js#L63](./contracts/sports-api.js#L63)
+5. Fulfill game result request [ResultsConsumer.sol#L105](./contracts/contracts/ResultsConsumer.sol#L105)
+6. Claim winnings [SportsPredictionGame.sol#L151](./contracts/contracts/SportsPredictionGame.sol#L151)<br>
+   6.1 Transfer winnings [NativeTokenSender.sol#L66](./contracts/contracts/ccip/NativeTokenSender.sol#L66)
 
 ## Resources
 

contracts/contracts/ResultsConsumer.sol

@@ -63,11 +63,14 @@ abstract contract ResultsConsumer is FunctionsClient {
   /// @param externalId The ID of the game on the external sports API
   /// @return requestId The Chainlink Functions request ID
   function _requestResult(uint256 sportId, uint256 externalId) internal returns (bytes32 requestId) {
+    // Prepare the arguments for the Chainlink Functions request
     string[] memory args = new string[](2);
     args[0] = Strings.toString(sportId);
     args[1] = Strings.toString(externalId);
+    // Send the Chainlink Functions request
     requestId = _executeRequest(args);
 
+    // Store the request and the associated data for the callback
     pending[requestId] = PendingRequest({sportId: sportId, externalId: externalId});
     emit RequestedResult(sportId, externalId, requestId);
   }
@@ -101,17 +104,20 @@ abstract contract ResultsConsumer is FunctionsClient {
   /// @dev This function is called by the oracle
   function fulfillRequest(bytes32 requestId, bytes memory response, bytes memory err) internal override {
     PendingRequest memory request = pending[requestId];
+    // Check if there is a sent request
     if (request.sportId == 0) {
       emit NoPendingRequest();
       return;
     }
     delete pending[requestId];
+    // Check if the Functions script failed
     if (err.length > 0) {
       emit RequestFailed(err);
       return;
     }
     emit ResultReceived(requestId, response);
 
+    // Call the child contract to process the result
     _processResult(request.sportId, request.externalId, response);
   }
 }

contracts/contracts/SportsPredictionGame.sol

@@ -117,16 +117,19 @@ contract SportsPredictionGame is ResultsConsumer, NativeTokenSender, AutomationC
     Game memory game = games[gameId];
     uint256 wagerAmount = msg.value;
 
+    // Check if the prediction is valid
     if (game.externalId == 0) revert GameNotRegistered();
     if (game.resolved) revert GameIsResolved();
     if (game.timestamp < block.timestamp) revert GameAlreadyStarted();
     if (wagerAmount < MIN_WAGER) revert InsufficientValue();
     if (wagerAmount > MAX_WAGER) revert ValueTooHigh();
 
+    // Update the game pool amounts
     if (result == Result.Home) games[gameId].homeWagerAmount += wagerAmount;
     else if (result == Result.Away) games[gameId].awayWagerAmount += wagerAmount;
     else revert InvalidResult();
 
+    // Add the prediction to the user's list of predictions
     predictions[msg.sender][gameId].push(Prediction(gameId, result, wagerAmount, false));
     emit Predicted(msg.sender, gameId, result, wagerAmount);
   }
@@ -151,14 +154,18 @@ contract SportsPredictionGame is ResultsConsumer, NativeTokenSender, AutomationC
 
     if (!game.resolved) revert GameNotResolved();
 
+    // Calculate the total winnings and mark the predictions as claimed
     uint256 totalWinnings = 0;
     Prediction[] memory userPredictions = predictions[user][gameId];
     for (uint256 i = 0; i < userPredictions.length; i++) {
       Prediction memory prediction = userPredictions[i];
+      // Skip if the prediction has already been claimed
       if (prediction.claimed) continue;
       if (game.result == Result.None) {
+        // For a draw, the user gets their tokens back
         totalWinnings += prediction.amount;
       } else if (prediction.result == game.result) {
+        // Calculate the winnings for correct predictions
         uint256 winnings = calculateWinnings(gameId, prediction.amount, prediction.result);
         totalWinnings += winnings;
       }
@@ -167,9 +174,12 @@ contract SportsPredictionGame is ResultsConsumer, NativeTokenSender, AutomationC
 
     if (totalWinnings == 0) revert NothingToClaim();
 
+    // Claim winnings depending on the transfer parameter
     if (transfer) {
+      // Transfer the winnings to the user on the another chain
       _sendTransferRequest(user, totalWinnings);
     } else {
+      // Transfer the winnings to the user on the same chain
       payable(user).transfer(totalWinnings);
     }
 
@@ -186,10 +196,13 @@ contract SportsPredictionGame is ResultsConsumer, NativeTokenSender, AutomationC
   function _registerGame(uint256 sportId, uint256 externalId, uint256 timestamp) internal returns (uint256 gameId) {
     gameId = getGameId(sportId, externalId);
 
+    // Check if the game can be registered
     if (games[gameId].externalId != 0) revert GameAlreadyRegistered();
     if (timestamp < block.timestamp) revert TimestampInPast();
 
+    // Store the game data
     games[gameId] = Game(sportId, externalId, timestamp, 0, 0, false, Result.None);
+    // Add the game to the active games list
     activeGames.push(gameId);
 
     emit GameRegistered(gameId);
@@ -201,11 +214,14 @@ contract SportsPredictionGame is ResultsConsumer, NativeTokenSender, AutomationC
   function _requestResolve(uint256 gameId) internal {
     Game memory game = games[gameId];
 
+    // Check if the game can be resolved
     if (pendingRequests[gameId] != 0) revert ResolveAlreadyRequested();
     if (game.externalId == 0) revert GameNotRegistered();
     if (game.resolved) revert GameIsResolved();
     if (!readyToResolve(gameId)) revert GameNotReadyToResolve();
 
+    // Request the result of the game via ResultsConsumer contract
+    // Store the Chainlink Functions request ID to prevent duplicate requests
     pendingRequests[gameId] = _requestResult(game.sportId, game.externalId);
   }
 
@@ -225,9 +241,11 @@ contract SportsPredictionGame is ResultsConsumer, NativeTokenSender, AutomationC
   /// @param result The result of the game
   /// @dev Removes the game from the active games list
   function _resolveGame(uint256 gameId, Result result) internal {
+    // Store the game result and mark the game as finished
     games[gameId].result = result;
     games[gameId].resolved = true;
 
+    // Add the game to the finished games list
     resolvedGames.push(gameId);
     _removeFromActiveGames(gameId);
 
@@ -338,7 +356,9 @@ contract SportsPredictionGame is ResultsConsumer, NativeTokenSender, AutomationC
   /// @dev The game must be registered
   function calculateWinnings(uint256 gameId, uint256 wager, Result result) public view returns (uint256) {
     Game memory game = games[gameId];
+    // Calculate the total amount of tokens wagered on the game
     uint256 totalWager = game.homeWagerAmount + game.awayWagerAmount;
+    // Calculate the winnings based on the result and the total amount of tokens wagered
     uint256 winnings = (wager * totalWager) / (result == Result.Home ? game.homeWagerAmount : game.awayWagerAmount);
     return winnings;
   }
@@ -357,10 +377,13 @@ contract SportsPredictionGame is ResultsConsumer, NativeTokenSender, AutomationC
   /// @notice Check if any games are ready to be resolved
   /// @dev Called by Chainlink Automation to determine if a game result should be requested
   function checkUpkeep(bytes memory) public view override returns (bool, bytes memory) {
+    // Get all games that can be resolved
     Game[] memory activeGamesArray = getActiveGames();
+    // Check if any game is ready to be resolved and have not already been requested
     for (uint256 i = 0; i < activeGamesArray.length; i++) {
       uint256 gameId = getGameId(activeGamesArray[i].sportId, activeGamesArray[i].externalId);
       if (readyToResolve(gameId) && pendingRequests[gameId] == 0) {
+        // Signal that a game is ready to be resolved to Chainlink Automation
         return (true, abi.encodePacked(gameId));
       }
     }

contracts/contracts/ccip/NativeTokenReceiver.sol

@@ -64,9 +64,11 @@ contract NativeTokenReceiver is ProgrammableTokenReceiver {
   function _onTokenReceived(bytes32, bytes memory data, address tokenAddress, uint256 tokenAmount) internal override {
     if (tokenAddress != exchangeToken) revert InvalidTokenAddress(tokenAddress);
 
+    // Swap exchange token to native token
     address tokenRecipient = abi.decode(data, (address));
     uint256 nativeTokenAmount = _swapExchangeTokenToNative(tokenAmount);
 
+    // Transfer native token to the recipient
     (bool success, ) = tokenRecipient.call{value: nativeTokenAmount}("");
     if (!success) revert FailedToTransferNativeToken(tokenRecipient);
 
@@ -77,7 +79,9 @@ contract NativeTokenReceiver is ProgrammableTokenReceiver {
   /// @param _exchangeTokenAmount The amount of exchange token to swap
   /// @return nativeTokenAmount The amount of native token received
   function _swapExchangeTokenToNative(uint256 _exchangeTokenAmount) internal returns (uint256 nativeTokenAmount) {
+    // Approve the Uniswap V3 router to spend the exchange token
     TransferHelper.safeApprove(exchangeToken, uniswapV3Router, _exchangeTokenAmount);
+    // Swap the exchange token to wrapped native token
     ISwapRouter.ExactInputSingleParams memory params = ISwapRouter.ExactInputSingleParams({
       tokenIn: exchangeToken,
       tokenOut: weth9Token,
@@ -89,6 +93,7 @@ contract NativeTokenReceiver is ProgrammableTokenReceiver {
       sqrtPriceLimitX96: 0
     });
     nativeTokenAmount = ISwapRouter(uniswapV3Router).exactInputSingle(params);
+    // Swap the wrapped native token to native token
     IWETH9(weth9Token).withdraw(nativeTokenAmount);
   }
 

contracts/contracts/ccip/NativeTokenSender.sol

@@ -65,7 +65,9 @@ abstract contract NativeTokenSender is ProgrammableTokenSender {
   /// @return requestId The ID of the CCIP message that was sent
   function _sendTransferRequest(address _to, uint256 _amount) internal returns (bytes32 requestId) {
     if (destinationContractReceiver == address(0)) revert NoDestinationContractReceiver();
+    // Swap native token to exchange token
     uint256 exchangeTokenAmount = _swapNativeToExchangeToken(_amount);
+    // Send the transfer request to CCIP
     requestId = _sendMessagePayLINK(
       destinationChainSelector,
       destinationContractReceiver,