import { describe, it, expect, beforeEach, vi } from 'vitest';

/**
 * Unit tests for auth.client.ts plugin
 *
 * This plugin is responsible for initializing the auth state when the app mounts.
 * It calls useAuth().initAuth() which:
 * 1. Syncs user from Pocketbase authStore (session restoration)
 * 2. Sets up cross-tab sync listener via pb.authStore.onChange()
 *
 * Tests written FIRST (TDD Red phase) - Implementation does not exist yet.
 * Expected: ALL TESTS WILL FAIL until T004 is implemented.
 *
 * Story Mapping:
 * - US4 (Session Persistence): Plugin enables session restoration on page load
 * - US5 (Cross-Tab Sync): Plugin sets up onChange listener for cross-tab synchronization
 */

// Mock useAuth composable
const mockInitAuth = vi.fn();
const mockUseAuth = vi.fn(() => ({
  initAuth: mockInitAuth,
  user: { value: null },
  isAuthenticated: { value: false },
  loading: { value: false },
  error: { value: null },
  login: vi.fn(),
  logout: vi.fn(),
  handleOAuthCallback: vi.fn(),
  refreshAuth: vi.fn(),
  authProviders: vi.fn(),
}));

// Mock the useAuth composable
vi.mock('../../composables/useAuth', () => ({
  useAuth: mockUseAuth,
}));

// Mock defineNuxtPlugin
const mockDefineNuxtPlugin = vi.fn((callback: Function) => {
  // Store the callback so we can invoke it in tests
  return { callback };
});

vi.mock('#app', () => ({
  defineNuxtPlugin: mockDefineNuxtPlugin,
}));

describe('auth.client plugin', () => {
  beforeEach(() => {
    vi.clearAllMocks();
  });

  describe('Plugin Initialization', () => {
    it('should call initAuth() exactly once when plugin executes', async () => {
      // Import the plugin (this will execute it)
      const plugin = await import('../auth.client');

      // The plugin should have called defineNuxtPlugin
      expect(mockDefineNuxtPlugin).toHaveBeenCalledTimes(1);

      // Get the plugin callback
      const pluginCallback = mockDefineNuxtPlugin.mock.results[0]?.value?.callback;
      expect(pluginCallback).toBeDefined();
      expect(typeof pluginCallback).toBe('function');

      // Execute the plugin callback
      pluginCallback();

      // Verify useAuth was called
      expect(mockUseAuth).toHaveBeenCalledTimes(1);

      // Verify initAuth was called exactly once
      expect(mockInitAuth).toHaveBeenCalledTimes(1);
      expect(mockInitAuth).toHaveBeenCalledWith();
    });

    it('should call useAuth composable to get auth methods', async () => {
      // Import the plugin
      const plugin = await import('../auth.client');

      // Get and execute the plugin callback
      const pluginCallback = mockDefineNuxtPlugin.mock.results[0]?.value?.callback;
      pluginCallback();

      // Verify useAuth was called
      expect(mockUseAuth).toHaveBeenCalled();
    });
  });

  describe('Plugin Execution Order', () => {
    it('should execute synchronously (not async)', async () => {
      // Import the plugin
      const plugin = await import('../auth.client');

      // Get the plugin callback
      const pluginCallback = mockDefineNuxtPlugin.mock.results[0]?.value?.callback;

      // The callback should not return a Promise
      const result = pluginCallback();
      expect(result).toBeUndefined();
    });

    it('should not call any other auth methods besides initAuth', async () => {
      // Create a mock with spy methods
      const spyLogin = vi.fn();
      const spyLogout = vi.fn();
      const spyHandleOAuthCallback = vi.fn();
      const spyRefreshAuth = vi.fn();

      mockUseAuth.mockReturnValue({
        initAuth: mockInitAuth,
        user: { value: null },
        isAuthenticated: { value: false },
        loading: { value: false },
        error: { value: null },
        login: spyLogin,
        logout: spyLogout,
        handleOAuthCallback: spyHandleOAuthCallback,
        refreshAuth: spyRefreshAuth,
        authProviders: vi.fn(),
      });

      // Import and execute the plugin
      const plugin = await import('../auth.client');
      const pluginCallback = mockDefineNuxtPlugin.mock.results[0]?.value?.callback;
      pluginCallback();

      // Verify only initAuth was called
      expect(mockInitAuth).toHaveBeenCalled();
      expect(spyLogin).not.toHaveBeenCalled();
      expect(spyLogout).not.toHaveBeenCalled();
      expect(spyHandleOAuthCallback).not.toHaveBeenCalled();
      expect(spyRefreshAuth).not.toHaveBeenCalled();
    });
  });

  describe('Client-Side Only Execution', () => {
    it('should be a client-side plugin (file named auth.client.ts)', async () => {
      // This test verifies the naming convention
      // Plugin files ending in .client.ts are automatically client-side only in Nuxt
      // We can't directly test this in unit tests, but we document the requirement

      // The file MUST be named auth.client.ts (not auth.ts)
      // This ensures it only runs in the browser, not during SSR

      const filename = 'auth.client.ts';
      expect(filename).toMatch(/\.client\.ts$/);
    });
  });

  describe('Integration with useAuth', () => {
    it('should enable session restoration via initAuth', async () => {
      // This test documents the expected behavior:
      // When initAuth() is called, it should:
      // 1. Sync user from pb.authStore.record
      // 2. Set up onChange listener for cross-tab sync

      const plugin = await import('../auth.client');
      const pluginCallback = mockDefineNuxtPlugin.mock.results[0]?.value?.callback;
      pluginCallback();

      // Verify initAuth was called (the actual restoration logic is tested in useAuth.test.ts)
      expect(mockInitAuth).toHaveBeenCalled();
    });
  });
});