import {
  ChangeDetectionStrategy,
  Component,
  DestroyRef,
  OnDestroy,
  OnInit,
  computed,
  inject,
  signal,
} from '@angular/core';
import { CommonModule } from '@angular/common';
import { NavigationEnd, Router, RouterOutlet } from '@angular/router';
import { filter } from 'rxjs/operators';
import { BootstrapService } from '../../core/services/bootstrap.service';
import { AuthService } from '../../core/services/auth.service';
import { EventStatusStore } from '../../core/services/event-status.store';
import { AuthenticatedEventSourceService } from '../../core/services/authenticated-event-source.service';
import { UserStore } from '../../core/services/user.store';
import { ChallengesStore } from '../challenges/challenges.store';
import { ShellHeaderComponent } from '../shell/header/shell-header.component';
import {
  ChangePasswordModalComponent,
  ChangePasswordSubmitPayload,
} from '../shell/change-password/change-password-modal.component';
import { ChangePasswordFailure, ChangePasswordResult } from '../../core/services/auth.service';
import { QuickTabsComponent, ShellTab } from '../shell/tabs/quick-tabs.component';
import { deriveActiveSectionFromUrl, shouldShowAdminNav } from './home.shell';
import { formatChangePasswordError } from '../shell/change-password/password-feedback';

const TABS: ShellTab[] = [
  { id: 'challenges', label: 'Challenges' },
  { id: 'scoreboard', label: 'Scoreboard' },
  { id: 'blog', label: 'Blog' },
];

@Component({
  selector: 'app-home',
  standalone: true,
  changeDetection: ChangeDetectionStrategy.OnPush,
  imports: [
    CommonModule,
    RouterOutlet,
    ShellHeaderComponent,
    ChangePasswordModalComponent,
    QuickTabsComponent,
  ],
  template: `
    <div class="container">
      <app-shell-header
        [pageTitle]="bootstrap.payload()?.pageTitle ?? 'HIPCTF'"
        [activeSection]="activeSection()"
        [eventState]="eventStatus.state()"
        [countdownText]="eventStatus.countdownText()"
        [username]="userStore.user()?.username ?? ''"
        [rankText]="userStore.rankText()"
        [canAccessAdmin]="canAccessAdmin()"
        [userMenuOpen]="userMenuOpen()"
        (titleClick)="goHome()"
        (usernameMenuToggle)="toggleUserMenu()"
        (rankClick)="navigateToSection('scoreboard')"
        (changePasswordClick)="openChangePassword()"
        (adminClick)="goAdmin()"
        (logoutClick)="onLogout()"
      />

      <app-quick-tabs
        [tabs]="TABS"
        [active]="activeTabId()"
        (tabChange)="navigateToSection($event.id)"
      />

      <section class="shell-body">
        <router-outlet></router-outlet>
      </section>

      <app-change-password-modal
        [open]="changePasswordOpen()"
        [mode]="'self'"
        [policy]="bootstrap.passwordPolicy()"
        [errorMessage]="changePasswordError()"
        [submitting]="changePasswordSubmitting()"
        (cancel)="closeChangePassword()"
        (submit)="submitChangePassword($event)"
      />
    </div>
  `,
})
export class HomeComponent implements OnInit, OnDestroy {
  readonly TABS = TABS;
  readonly bootstrap = inject(BootstrapService);
  readonly auth = inject(AuthService);
  readonly eventStatus = inject(EventStatusStore);
  private readonly authenticatedEventSource = inject(AuthenticatedEventSourceService);
  readonly userStore = inject(UserStore);
  private readonly challengesStore = inject(ChallengesStore);
  private readonly router = inject(Router);
  private readonly destroyRef = inject(DestroyRef);

  readonly userMenuOpen = signal(false);
  readonly changePasswordOpen = signal(false);
  readonly changePasswordSubmitting = signal(false);
  readonly changePasswordError = signal<string | null>(null);

  private readonly currentUrl = signal<string>(this.router.url || '/');

  readonly activeSection = computed(() => deriveActiveSectionFromUrl(this.currentUrl()));
  readonly activeTabId = computed(() => {
    const url = this.currentUrl();
    if (url.startsWith('/scoreboard')) return 'scoreboard';
    if (url.startsWith('/blog')) return 'blog';
    if (url.startsWith('/admin')) return 'admin';
    return 'challenges';
  });

  readonly canAccessAdmin = computed(() =>
    shouldShowAdminNav({
      isAuthenticated: this.auth.isAuthenticated(),
      role: this.auth.currentUser()?.role,
    }),
  );

  constructor() {
    this.router.events
      .pipe(filter((e): e is NavigationEnd => e instanceof NavigationEnd))
      .subscribe((e) => this.currentUrl.set(e.urlAfterRedirects || e.url));
    this.destroyRef.onDestroy(() => {
      this.eventStatus.stop();
    });
  }

  ngOnInit(): void {
    this.userStore.hydrateFromAuth();
    void this.userStore.loadMe();
    this.eventStatus.start(
      () => this.authenticatedEventSource.open('/api/v1/events/status'),
      () => this.handleSessionInvalidated('sse-unauthorized'),
    );
    this.peerInvalidationUnsubscribe = this.auth.onPeerInvalidation((reason) =>
      this.handleSessionInvalidated(reason),
    );
  }

  ngOnDestroy(): void {
    this.eventStatus.stop();
    if (this.peerInvalidationUnsubscribe) {
      this.peerInvalidationUnsubscribe();
      this.peerInvalidationUnsubscribe = null;
    }
  }

  goHome(): void {
    void this.router.navigateByUrl('/challenges');
    this.userMenuOpen.set(false);
  }

  goAdmin(): void {
    void this.router.navigateByUrl('/admin');
    this.userMenuOpen.set(false);
  }

  toggleUserMenu(): void {
    this.userMenuOpen.update((v) => !v);
  }

  navigateToSection(id: string): void {
    if (id === 'admin') {
      void this.router.navigateByUrl('/admin');
    } else {
      void this.router.navigateByUrl('/' + id);
    }
    this.userMenuOpen.set(false);
  }

  openChangePassword(): void {
    this.changePasswordError.set(null);
    this.changePasswordOpen.set(true);
    this.userMenuOpen.set(false);
  }

  closeChangePassword(): void {
    if (this.changePasswordSubmitting()) return;
    this.changePasswordOpen.set(false);
    this.changePasswordError.set(null);
  }

  async submitChangePassword(payload: ChangePasswordSubmitPayload): Promise<void> {
    this.changePasswordSubmitting.set(true);
    this.changePasswordError.set(null);
    const result: ChangePasswordResult = await this.auth.changePassword(payload);
    this.changePasswordSubmitting.set(false);
    if (result.ok === true) {
      this.changePasswordOpen.set(false);
      return;
    }
    const failure = result as ChangePasswordFailure;
    this.changePasswordError.set(
      formatChangePasswordError({ code: failure.code, message: failure.message }),
    );
  }

  async onLogout(): Promise<void> {
    await this.auth.logout();
    this.userMenuOpen.set(false);
    this.userStore.reset();
    this.challengesStore.reset();
    await this.router.navigateByUrl('/login');
  }

  private peerInvalidationUnsubscribe: (() => void) | null = null;
  private navigatingToLogin = false;

  private async handleSessionInvalidated(
    _reason: 'peer-logout' | 'sse-unauthorized',
  ): Promise<void> {
    this.userStore.reset();
    this.challengesStore.reset();
    this.changePasswordOpen.set(false);
    this.userMenuOpen.set(false);
    if (this.navigatingToLogin) return;
    if (this.router.url.startsWith('/login')) return;
    this.navigatingToLogin = true;
    try {
      await this.router.navigateByUrl('/login');
    } finally {
      this.navigatingToLogin = false;
    }
  }
}