From 11c597e4ba5a7384f6100ff5c5beccbae8ab38a7 Mon Sep 17 00:00:00 2001
From: Abhishek <punhaniabhishek17@gmsil.com>
Date: Sat, 22 Jun 2024 13:31:45 +0530
Subject: [PATCH] Added Event Handler

Handles different events and updates the game state accordingly

Also Integrated with GameProvider to handle these events
---
 frontend/src/clientDispatch.ts        | 123 ++++++++++++++++++++++++++
 frontend/src/contexts/GameContext.tsx |  37 ++++----
 2 files changed, 140 insertions(+), 20 deletions(-)
 create mode 100644 frontend/src/clientDispatch.ts

diff --git a/frontend/src/clientDispatch.ts b/frontend/src/clientDispatch.ts
new file mode 100644
index 0000000..095fbc0
--- /dev/null
+++ b/frontend/src/clientDispatch.ts
@@ -0,0 +1,123 @@
+import { GameEvent, GameEventTypes } from '../../backend/src/types';
+import { GameState } from './contexts/GameContext';
+import { triggerEvent } from './channel';
+
+export const clientDispatch = (
+    gameState: GameState,
+    event: GameEvent
+): GameState => {
+    let newGameState: GameState;
+
+    switch (event.type) {
+        case GameEventTypes.JOIN_GAME:
+            newGameState = handleJoinGame(gameState, event);
+            break;
+        case GameEventTypes.LEAVE_GAME:
+            newGameState = handleLeaveGame(gameState, event);
+            break;
+        case GameEventTypes.DRAW_CARD:
+            newGameState = handleDrawCard(gameState, event);
+            break;
+        case GameEventTypes.THROW_CARD:
+            newGameState = handleThrowCard(gameState, event);
+            break;
+        case GameEventTypes.STATE_SYNC:
+            newGameState = handleStateSync(gameState, event);
+            break;
+        default:
+            throw new Error(`Unhandled event type: ${event}`);
+    }
+
+    // Trigger the event to the server
+    triggerEvent(event);
+
+    return newGameState;
+};
+
+const handleJoinGame = (gameState: GameState, event: GameEvent): GameState => {
+    if (event.type !== GameEventTypes.JOIN_GAME) {
+        throw new Error(`Invalid event type for handleJoinGame: ${event.type}`);
+    }
+    const { playerId } = event;
+    return {
+        ...gameState,
+        players: [...gameState.players, { id: playerId, cards: [] }],
+    };
+};
+
+const handleLeaveGame = (gameState: GameState, event: GameEvent): GameState => {
+    if (event.type !== GameEventTypes.LEAVE_GAME) {
+        throw new Error(
+            `Invalid event type for handleLeaveGame: ${event.type}`
+        );
+    }
+    const { playerId } = event;
+    return {
+        ...gameState,
+        players: gameState.players.filter((player) => player.id !== playerId),
+    };
+};
+
+const handleDrawCard = (gameState: GameState, event: GameEvent): GameState => {
+    if (event.type !== GameEventTypes.DRAW_CARD) {
+        throw new Error(`Invalid event type for handleDrawCard: ${event.type}`);
+    }
+
+    const { playerId } = event;
+
+    // Find the player who drew the card
+    const updatedPlayers = gameState.players.map((player) => {
+        if (player.id === playerId) {
+            // Assume the last card in the player's deck is the drawn card
+            const drawnCardId = player.cards[player.cards.length - 1]; // Last drawn card
+            const updatedCards = [...player.cards, drawnCardId];
+            return { ...player, cards: updatedCards };
+        }
+        return player;
+    });
+
+    return {
+        ...gameState,
+        players: updatedPlayers,
+    };
+};
+
+const handleThrowCard = (gameState: GameState, event: GameEvent): GameState => {
+    if (event.type !== GameEventTypes.THROW_CARD) {
+        throw new Error(
+            `Invalid event type for handleThrowCard: ${event.type}`
+        );
+    }
+    const { playerId, data } = event;
+    const { cardId } = data;
+    return {
+        ...gameState,
+        players: gameState.players.map((player) =>
+            player.id === playerId
+                ? { ...player, cards: player.cards.filter((c) => c !== cardId) }
+                : player
+        ),
+        lastThrownCard: cardId,
+    };
+};
+
+const handleStateSync = (gameState: GameState, event: GameEvent): GameState => {
+    if (event.type !== GameEventTypes.STATE_SYNC) {
+        throw new Error(
+            `Invalid event type for handleStateSync: ${event.type}`
+        );
+    }
+    const { data } = event;
+    const mappedPlayers = data.players.map((player) => ({
+        id: player.id,
+        cards: player.cards.map((card) => card.id),
+    }));
+
+    return {
+        ...gameState,
+        players: mappedPlayers,
+        cards: data.cards.map((card) => card.id),
+        currentTurn: data.currentTurn,
+        lastThrownCard: data.lastThrownCard,
+    };
+};
diff --git a/frontend/src/contexts/GameContext.tsx b/frontend/src/contexts/GameContext.tsx
index 223736a..83adf00 100644
--- a/frontend/src/contexts/GameContext.tsx
+++ b/frontend/src/contexts/GameContext.tsx
@@ -5,8 +5,10 @@ import { useLocation, useNavigate } from 'react-router-dom';
 import { useAuth } from './AuthContext';
 import { useToast } from '../library/toast/toast-context';
 import * as channel from '../channel';
+import { clientDispatch } from '../clientDispatch';
+import { GameEvent } from '../../../backend/src/types';
 
-interface GameState {
+export interface GameState {
     players: { id: string; cards: string[] }[];
     cards: string[];
     currentTurn: number;
@@ -40,7 +42,11 @@ export const GameProvider = () => {
     const toast = useToast();
     const auth = useAuth();
     const backendUrl = process.env.REACT_APP_BACKEND_URL;
-
+    const dispatchGameEvent = (event: GameEvent) => {
+        setGameState((prevState) =>
+            clientDispatch(prevState as GameState, event)
+        );
+    };
     useEffect(() => {
         if (!auth.isLoggedIn()) {
             navigate('/');
@@ -109,25 +115,16 @@ export const GameProvider = () => {
 
     // polling
     useEffect(() => {
-        // add event listener to listen for the game state changes
-        channel.setGameEventsDispatcher((event) => {
-            // todo: this callback will be replaced by the event dispatcher
-            console.log('Handling event:', event);
-            if (event.type === 'STATE_SYNC') {
-                setGameState({
-                    players: event.data.players.map((player) => {
-                        return {
-                            id: player.id,
-                            cards: player.cards.map((card) => card.id),
-                        };
-                    }),
-                    cards: event.data.cards.map((card) => card.id),
-                    currentTurn: event.data.currentTurn,
-                    lastThrownCard: event.data.lastThrownCard,
-                });
-            }
+        channel.setGameEventsDispatcher((event: GameEvent) => {
+            dispatchGameEvent(event);
         });
-    }, [gameState]);
+
+        channel.startPolling();
+
+        return () => {
+            channel.stopPolling();
+        };
+    }, []);
 
     return (
         <GameContext.Provider value={{ gameState, setGameState }}>