import { CommonModule } from '@angular/common';
import {
  ChangeDetectionStrategy,
  Component,
  computed,
  DestroyRef,
  effect,
  inject,
  ViewChild,
} from '@angular/core';
import { Router, RouterLink, RouterOutlet, NavigationEnd, TitleStrategy } from '@angular/router';
import { takeUntilDestroyed, toSignal } from '@angular/core/rxjs-interop';
import { filter, map, startWith, take } from 'rxjs/operators';

import { AuthorityAuthService } from './core/auth/authority-auth.service';
import { AuthSessionStore } from './core/auth/auth-session.store';
import { ConsoleSessionStore } from './core/console/console-session.store';
import { DoctorTrendService } from './core/doctor/doctor-trend.service';
import { DoctorNotificationService } from './core/doctor/doctor-notification.service';
import { NavigationMenuComponent } from './shared/components/navigation-menu/navigation-menu.component';
import { UserMenuComponent } from './shared/components/user-menu/user-menu.component';
import { CommandPaletteComponent } from './shared/components/command-palette/command-palette.component';
import { ToastContainerComponent } from './shared/components/toast/toast-container.component';
import { BreadcrumbComponent } from './shared/components/breadcrumb/breadcrumb.component';
import { KeyboardShortcutsComponent } from './shared/components/keyboard-shortcuts/keyboard-shortcuts.component';
import { AppShellComponent } from './layout/app-shell/app-shell.component';
import { BrandingService } from './core/branding/branding.service';
import { LegacyRouteTelemetryService } from './core/guards/legacy-route-telemetry.service';
import { LegacyUrlBannerComponent } from './shared/ui/legacy-url-banner/legacy-url-banner.component';
import { PlatformContextUrlSyncService } from './core/context/platform-context-url-sync.service';
import { TranslatePipe } from './core/i18n';

@Component({
    selector: 'app-root',
    imports: [
        CommonModule,
        RouterOutlet,
        RouterLink,
        NavigationMenuComponent,
        UserMenuComponent,
        AppShellComponent,
        CommandPaletteComponent,
        ToastContainerComponent,
        BreadcrumbComponent,
        KeyboardShortcutsComponent,
        LegacyUrlBannerComponent,
        TranslatePipe,
    ],
    templateUrl: './app.component.html',
    styleUrl: './app.component.scss',
    changeDetection: ChangeDetectionStrategy.OnPush
})
export class AppComponent {
  private static readonly SHELL_EXCLUDED_ROUTES = [
    '/setup-wizard',
    '/welcome',
    '/callback',
    '/silent-refresh',
    '/auth/callback',
    '/auth/silent-refresh',
  ];

  private readonly router = inject(Router);
  private readonly titleStrategy = inject(TitleStrategy);
  private readonly auth = inject(AuthorityAuthService);
  private readonly sessionStore = inject(AuthSessionStore);
  private readonly consoleStore = inject(ConsoleSessionStore);
  private readonly brandingService = inject(BrandingService);
  private readonly legacyRouteTelemetry = inject(LegacyRouteTelemetryService);
  private readonly contextUrlSync = inject(PlatformContextUrlSyncService);
  private readonly doctorTrend = inject(DoctorTrendService);
  private readonly doctorNotification = inject(DoctorNotificationService);
  private shellBackgroundServicesActive = false;

  @ViewChild(CommandPaletteComponent) private commandPalette!: CommandPaletteComponent;

  private readonly destroyRef = inject(DestroyRef);

  constructor() {
    const removeSplash = () => {
      const splash = document.getElementById('stella-splash');
      if (!splash) {
        return;
      }
      splash.style.opacity = '0';
      splash.style.transition = 'opacity 0.3s ease-out';
      setTimeout(() => splash.remove(), 350);
    };

    // Remove the inline splash screen once the first route resolves.
    // This keeps the splash visible while route guards (e.g. backend probe)
    // are still pending, avoiding a blank screen.
    this.router.events
      .pipe(
        filter((e): e is NavigationEnd => e instanceof NavigationEnd),
        take(1),
        takeUntilDestroyed(this.destroyRef),
      )
      .subscribe(() => removeSplash());

    // Defensive fallback: if first navigation never settles (e.g. test/misconfigured
    // backend), remove splash so the shell remains interactive.  Use 10s to match
    // the silent-refresh iframe timeout so the splash stays visible while OIDC
    // session restoration is in-flight.
    setTimeout(() => removeSplash(), 10_000);

    // Initialize branding on app start
    this.brandingService.fetchBranding().subscribe();

    effect(() => {
      this.brandingService.currentBranding();
      this.brandingService.isLoaded();
      this.currentUrl();
      this.titleStrategy.updateTitle(this.router.routerState.snapshot);
    });

    // Attempt to silently restore the auth session if the user was
    // previously logged in (session cookie may still be active at the Authority).
    void this.auth.trySilentRefresh();

    // Initialize legacy route telemetry tracking (ROUTE-002)
    this.legacyRouteTelemetry.initialize();

    effect(() => {
      const shouldRunShellBackgroundServices =
        this.isAuthenticated() && !this.isShellExcludedRoute(this.currentUrl());

      if (shouldRunShellBackgroundServices) {
        if (this.shellBackgroundServicesActive) {
          return;
        }

        // Keep global scope in sync with route query parameters only once the
        // authenticated shell is active.
        this.contextUrlSync.initialize();

        // Start Doctor background services (deferred from APP_INITIALIZER
        // to avoid NG0200 circular DI with Router during bootstrap).
        this.doctorTrend.start();
        this.doctorNotification.start();
        this.shellBackgroundServicesActive = true;
        return;
      }

      if (!this.shellBackgroundServicesActive) {
        return;
      }

      this.doctorTrend.stop();
      this.doctorNotification.stop();
      this.shellBackgroundServicesActive = false;
    });
  }

  readonly isAuthenticated = this.sessionStore.isAuthenticated;
  readonly authStatus = this.sessionStore.status;
  readonly activeTenant = this.consoleStore.selectedTenantId;

  readonly freshAuthSummary = computed(() => {
    const token = this.consoleStore.tokenInfo();
    if (!token) {
      return null;
    }
    return {
      active: token.freshAuthActive,
      expiresAt: token.freshAuthExpiresAt,
    };
  });

  // Legacy route info for banner (ROUTE-003)
  readonly legacyRouteInfo = this.legacyRouteTelemetry.currentLegacyRoute;

  private readonly currentUrl$ = this.router.events.pipe(
    filter((event): event is NavigationEnd => event instanceof NavigationEnd),
    map(event => event.urlAfterRedirects.split('?')[0]),
    startWith(this.router.url.split('?')[0])
  );

  private readonly currentUrl = toSignal(this.currentUrl$, {
    initialValue: (typeof window !== 'undefined' ? window.location.pathname : '/'),
  });

  readonly useShellLayout = computed(() => {
    const url = this.currentUrl();
    return this.isAuthenticated() && !this.isShellExcludedRoute(url);
  });

  readonly showBreadcrumb = computed(() => {
    const url = this.currentUrl();
    const hideRoutes = [
      '/',
      '/welcome',
      ...AppComponent.SHELL_EXCLUDED_ROUTES,
    ];
    if (hideRoutes.some(route => url === route || url.startsWith(route + '/'))) {
      return false;
    }
    return url.split('/').filter(s => s).length > 0;
  });

  /** Setup wizard gets a completely chrome-free viewport. */
  readonly isFullPageRoute = computed(() => {
    const url = this.currentUrl();
    return url === '/setup-wizard' || url.startsWith('/setup-wizard/');
  });

  /** Hide navigation on setup/auth pages and when not authenticated. */
  readonly showNavigation = computed(() => {
    const url = this.currentUrl();
    if (this.isShellExcludedRoute(url)) {
      return false;
    }
    return this.isAuthenticated();
  });

  /** Show sign-in only on pages where auth makes sense (not setup/callback). */
  readonly showSignIn = computed(() => {
    const url = this.currentUrl();
    return !this.isShellExcludedRoute(url);
  });

  onSignIn(): void {
    const returnUrl = this.router.url === '/' ? undefined : this.router.url;
    void this.auth.beginLogin(returnUrl);
  }

  onLegacyBannerDismissed(): void {
    this.legacyRouteTelemetry.clearCurrentLegacyRoute();
  }

  /** Triggered by the keyboard easter egg (typing d-e-m-o quickly) */
  onDemoSeedRequested(): void {
    this.commandPalette?.triggerSeedDemo();
  }

  private isShellExcludedRoute(url: string): boolean {
    return AppComponent.SHELL_EXCLUDED_ROUTES.some(
      (route) => url === route || url.startsWith(route + '/')
    );
  }
}