feat(modelAvailabilityService): integrate model availability service into backend logic (#14470)

packages/core/src/config/config.test.ts

@@ -1632,3 +1632,42 @@ describe('Config setExperiments logging', () => {
     debugSpy.mockRestore();
   });
 });
+
+describe('Availability Service Integration', () => {
+  const baseModel = 'test-model';
+  const baseParams: ConfigParameters = {
+    sessionId: 'test',
+    targetDir: '.',
+    debugMode: false,
+    model: baseModel,
+    cwd: '.',
+  };
+
+  it('setActiveModel updates active model and emits event', async () => {
+    const config = new Config(baseParams);
+    const model1 = 'model1';
+    const model2 = 'model2';
+
+    config.setActiveModel(model1);
+    expect(config.getActiveModel()).toBe(model1);
+    expect(mockCoreEvents.emitModelChanged).toHaveBeenCalledWith(model1);
+
+    config.setActiveModel(model2);
+    expect(config.getActiveModel()).toBe(model2);
+    expect(mockCoreEvents.emitModelChanged).toHaveBeenCalledWith(model2);
+  });
+
+  it('getActiveModel defaults to configured model if not set', () => {
+    const config = new Config(baseParams);
+    expect(config.getActiveModel()).toBe(baseModel);
+  });
+
+  it('resetTurn delegates to availability service', () => {
+    const config = new Config(baseParams);
+    const service = config.getModelAvailabilityService();
+    const spy = vi.spyOn(service, 'resetTurn');
+
+    config.resetTurn();
+    expect(spy).toHaveBeenCalled();
+  });
+});

packages/core/src/config/config.ts

@@ -382,6 +382,7 @@ export class Config {
   private ideMode: boolean;
 
   private inFallbackMode = false;
+  private _activeModel: string;
   private readonly maxSessionTurns: number;
   private readonly listSessions: boolean;
   private readonly deleteSession: string | undefined;
@@ -504,6 +505,7 @@ export class Config {
     this.fileDiscoveryService = params.fileDiscoveryService ?? null;
     this.bugCommand = params.bugCommand;
     this.model = params.model;
+    this._activeModel = params.model;
     this.enableModelAvailabilityService =
       params.enableModelAvailabilityService ?? false;
     this.enableAgents = params.enableAgents ?? false;
@@ -810,11 +812,28 @@ export class Config {
   setModel(newModel: string): void {
     if (this.model !== newModel || this.inFallbackMode) {
       this.model = newModel;
+      // When the user explicitly sets a model, that becomes the active model.
+      this._activeModel = newModel;
       coreEvents.emitModelChanged(newModel);
     }
     this.setFallbackMode(false);
   }
 
+  getActiveModel(): string {
+    return this._activeModel ?? this.model;
+  }
+
+  setActiveModel(model: string): void {
+    if (this._activeModel !== model) {
+      this._activeModel = model;
+      coreEvents.emitModelChanged(model);
+    }
+  }
+
+  resetTurn(): void {
+    this.modelAvailabilityService.resetTurn();
+  }
+
   isInFallbackMode(): boolean {
     return this.inFallbackMode;
   }