import { CommonModule } from '@angular/common';
import { Component, effect, inject, signal } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { Router, RouterLink } from '@angular/router';

import { ChatSessionService } from './chat-session.service';
import type { AdminUserSummary } from './models';
import { ThemeService } from './theme.service';

@Component({
  selector: 'app-home-page',
  imports: [CommonModule, FormsModule, RouterLink],
  templateUrl: './home-page.component.html',
  styleUrl: './home-page.component.scss',
})
export class HomePageComponent {
  private readonly router = inject(Router);
  readonly theme = inject(ThemeService);
  authMode: 'login' | 'register' = 'login';
  readonly embeddedMode =
    typeof window !== 'undefined' && window.localStorage.getItem('privatechat.embeddedMode') === '1';
  serverUrl = '';
  displayName = '';
  username = '';
  password = '';
  accessKeyLabel = '';
  readonly adminUsers = signal<AdminUserSummary[]>([]);
  readonly loadingAdminUsers = signal(false);
  readonly deletingUserId = signal<string | null>(null);
  readonly adminUsersError = signal<string | null>(null);

  constructor(readonly session: ChatSessionService) {
    this.serverUrl = session.serverUrl();

    if (this.embeddedMode) {
      effect(() => {
        const currentUser = this.session.currentUser();
        const activePeerId = this.session.activePeerId();

        if (!currentUser || !activePeerId) {
          return;
        }

        void this.router.navigate(['/chat', activePeerId], { replaceUrl: true });
      });
    }

    effect(() => {
      const currentUser = this.session.currentUser();

      if (!currentUser || !this.session.isApprovalAdmin()) {
        this.adminUsers.set([]);
        this.adminUsersError.set(null);
        this.loadingAdminUsers.set(false);
        return;
      }

      void this.reloadAdminUsers();
    });
  }

  async submitAuth(): Promise<void> {
    this.applyServerUrl();

    if (this.authMode === 'register') {
      const authenticated = await this.session.register(this.username, this.password, this.displayName);
      this.password = '';

      if (!authenticated) {
        this.authMode = 'login';
      }

      return;
    }

    await this.session.login(this.username, this.password);
  }

  applyServerUrl(): void {
    this.session.setServerUrl(this.serverUrl);
  }

  async logout(): Promise<void> {
    await this.session.logout();
    this.authMode = 'login';
    this.displayName = '';
    this.password = '';
  }

  async loginWithAccessKey(): Promise<void> {
    this.applyServerUrl();
    await this.session.loginWithAccessKey(this.username);
    this.password = '';
  }

  async registerAccessKey(): Promise<void> {
    await this.session.registerAccessKey(this.accessKeyLabel);
    this.accessKeyLabel = '';
  }

  async reloadAdminUsers(): Promise<void> {
    this.loadingAdminUsers.set(true);
    this.adminUsersError.set(null);

    try {
      this.adminUsers.set(await this.session.loadAdminUsers());
    } catch (error) {
      this.adminUsersError.set(
        error instanceof Error ? error.message : 'Could not load users.',
      );
    } finally {
      this.loadingAdminUsers.set(false);
    }
  }

  async deleteUser(user: AdminUserSummary): Promise<void> {
    if (
      typeof window !== 'undefined' &&
      !window.confirm(`Delete user ${user.username}? This removes the account from SQLite.`)
    ) {
      return;
    }

    this.deletingUserId.set(user.id);
    this.adminUsersError.set(null);

    try {
      await this.session.deleteUserAccount(user.id);
      this.adminUsers.update((users) => users.filter((candidate) => candidate.id !== user.id));
    } catch (error) {
      this.adminUsersError.set(
        error instanceof Error ? error.message : 'Could not delete that user.',
      );
    } finally {
      this.deletingUserId.set(null);
    }
  }

  async openChatUi(): Promise<void> {
    const peerId = this.session.activePeerId() ?? this.session.peers()[0]?.id;

    if (peerId) {
      this.session.selectPeer(peerId);
      await this.router.navigate(['/chat', peerId]);
      return;
    }

    this.session.error.set(null);
    await this.router.navigate(['/chat']);
  }

  cycleTheme(): void {
    this.theme.cycleMode();
  }
}