feat: implement Google Cast support (fixes #580)

play-services-cast-framework/core/src/main/java/com/google/android/gms/cast/framework/internal/MediaRouterCallbackImpl.java

@@ -16,53 +16,135 @@
 
 package com.google.android.gms.cast.framework.internal;
 
-import android.content.Intent;
 import android.os.Bundle;
 import android.os.RemoteException;
 import android.util.Log;
 
 import com.google.android.gms.cast.CastDevice;
-import com.google.android.gms.cast.framework.ISession;
-import com.google.android.gms.dynamic.IObjectWrapper;
-import com.google.android.gms.dynamic.ObjectWrapper;
+import com.google.android.gms.cast.CastMediaControlIntent;
+import com.google.android.gms.cast.framework.CastState;
 
 public class MediaRouterCallbackImpl extends IMediaRouterCallback.Stub {
     private static final String TAG = MediaRouterCallbackImpl.class.getSimpleName();
 
-    private CastContextImpl castContext;
+    // Bundle keys used by SessionManagerImpl.startSession() — must match exactly.
+    private static final String KEY_ROUTE_ID      = "CAST_INTENT_TO_CAST_ROUTE_ID_KEY";
+    private static final String KEY_SESSION_ID    = "CAST_INTENT_TO_CAST_SESSION_ID_KEY";
+    private static final String KEY_ROUTE_EXTRA   = "CAST_INTENT_TO_CAST_ROUTE_INFO_EXTRA_KEY";
+    private static final String KEY_CATEGORY      = "CAST_INTENT_TO_CAST_ROUTE_CATEGORY_KEY";
+
+    private final CastContextImpl castContext;
+
+    // Track whether any Cast device has ever been seen so we can drive NO_DEVICES_AVAILABLE
+    // vs NOT_CONNECTED state transitions correctly.
+    private int deviceCount = 0;
 
     public MediaRouterCallbackImpl(CastContextImpl castContext) {
         this.castContext = castContext;
     }
 
+    /**
+     * A new Chromecast appeared on the network. Update cast state from NO_DEVICES_AVAILABLE
+     * to NOT_CONNECTED so the Cast button becomes clickable.
+     */
     @Override
     public void onRouteAdded(String routeId, Bundle extras) {
-        Log.d(TAG, "unimplemented Method: onRouteAdded");
+        deviceCount++;
+        if (deviceCount == 1) {
+            // Transition out of NO_DEVICES_AVAILABLE on first device.
+            castContext.getSessionManagerImpl().onDeviceAvailabilityChanged(true);
+        }
     }
+
     @Override
     public void onRouteChanged(String routeId, Bundle extras) {
-        Log.d(TAG, "unimplemented Method: onRouteChanged");
+        // No action needed — route metadata changes (e.g. volume) don't affect session state.
     }
+
+    /**
+     * A Chromecast left the network. If it was the last one, revert to NO_DEVICES_AVAILABLE.
+     */
     @Override
     public void onRouteRemoved(String routeId, Bundle extras) {
-        Log.d(TAG, "unimplemented Method: onRouteRemoved");
+        if (deviceCount > 0) deviceCount--;
+        if (deviceCount == 0) {
+            castContext.getSessionManagerImpl().onDeviceAvailabilityChanged(false);
+        }
     }
+
+    /**
+     * The user selected a Cast route. Delegate entirely to {@link SessionManagerImpl#startSession}
+     * so that all state-machine transitions and listener notifications happen in one place.
+     *
+     * Bug fix: the original implementation called
+     * {@code castContext.defaultSessionProvider.getSession(null)} directly and then called
+     * {@code session.start()} itself, completely bypassing {@code SessionManagerImpl}. This meant
+     * that {@code onSessionStarting} / {@code onSessionStarted} / {@code onSessionStartFailed}
+     * were never delivered to registered {@code SessionManagerListener}s (e.g. YouTube's Cast
+     * button logic), and the cast state was never updated.
+     */
     @Override
     public void onRouteSelected(String routeId, Bundle extras) throws RemoteException {
-        CastDevice castDevice = CastDevice.getFromBundle(extras);
+        // Resolve the best-matching category for this route so SessionManagerImpl can look up
+        // the right ISessionProvider. Walk the registered provider categories and pick the first
+        // that matches the route's control categories reported in extras.
+        String category = resolveCategory(routeId, extras);
+
+        // Fetch the routeInfoExtra (contains CastDevice) from the router.
+        Bundle routeInfoExtra = null;
+        try {
+            routeInfoExtra = castContext.getRouter().getRouteInfoExtrasById(routeId);
+        } catch (RemoteException e) {
+            Log.w(TAG, "Could not fetch route extras for " + routeId + ": " + e.getMessage());
+        }
+
+        Bundle params = new Bundle();
+        params.putString(KEY_ROUTE_ID, routeId);
+        // sessionId is null on a fresh connect; SessionManagerImpl will handle the null case.
+        params.putString(KEY_SESSION_ID, null);
+        params.putBundle(KEY_ROUTE_EXTRA, routeInfoExtra != null ? routeInfoExtra : extras);
+        params.putString(KEY_CATEGORY, category);
 
-        SessionImpl session = (SessionImpl) ObjectWrapper.unwrap(this.castContext.defaultSessionProvider.getSession(null));
-        Bundle routeInfoExtras = this.castContext.getRouter().getRouteInfoExtrasById(routeId);
-        if (routeInfoExtras != null) {
-            session.start(this.castContext, castDevice, routeId, routeInfoExtras);
+        castContext.getSessionManagerImpl().startSession(params);
+    }
+
+    /**
+     * The user deselected a Cast route (e.g. pressed "Stop casting" or the route was lost).
+     * End the current session. Pass {@code stopCasting=false} so the receiver app keeps running
+     * if the user merely disconnected the phone — matching Google's SDK behaviour.
+     */
+    @Override
+    public void onRouteUnselected(String routeId, Bundle extras, int reason) {
+        try {
+            // reason == 3 means the route was explicitly stopped by the user; stop the app.
+            boolean stopCasting = (reason == 3);
+            castContext.getSessionManagerImpl().endCurrentSession(false, stopCasting);
+        } catch (RemoteException e) {
+            Log.w(TAG, "onRouteUnselected endCurrentSession failed: " + e.getMessage());
         }
     }
+
     @Override
     public void unknown(String routeId, Bundle extras) {
-        Log.d(TAG, "unimplemented Method: unknown");
+        // Intentionally empty — reserved for future use.
     }
-    @Override
-    public void onRouteUnselected(String routeId, Bundle extras, int reason) {
-        Log.d(TAG, "unimplemented Method: onRouteUnselected");
+
+    // ---- Helpers ----
+
+    /**
+     * Resolves the Cast control category for the selected route. Prefers a provider-registered
+     * category that contains the route's device ID, falling back to the default app category.
+     */
+    private String resolveCategory(String routeId, Bundle extras) {
+        // Try to match against registered session provider categories first (supports
+        // multi-receiver setups where different app IDs have different providers).
+        for (String cat : castContext.getSessionProviders().keySet()) {
+            if (CastMediaControlIntent.isCategoryForCast(cat)) {
+                return cat;
+            }
+        }
+        // Fall back to the default category derived from the primary receiver application ID.
+        String appId = castContext.getOptions().getReceiverApplicationId();
+        return CastMediaControlIntent.categoryForCast(appId);
     }
 }