import { Component, inject, signal, computed, OnInit } from '@angular/core';
import { CommonModule, DatePipe } from '@angular/common';
import { Router, RouterLink } from '@angular/router';
import { NzTableModule } from 'ng-zorro-antd/table';
import { NzButtonModule } from 'ng-zorro-antd/button';
import { NzIconModule } from 'ng-zorro-antd/icon';
import { NzTagModule } from 'ng-zorro-antd/tag';
import { NzBadgeModule } from 'ng-zorro-antd/badge';
import { NzEmptyModule } from 'ng-zorro-antd/empty';
import { NzCardModule } from 'ng-zorro-antd/card';
import { NzToolTipModule } from 'ng-zorro-antd/tooltip';
import { NzTabsModule } from 'ng-zorro-antd/tabs';
import { NzAlertModule } from 'ng-zorro-antd/alert';
import { ApiService } from '../../../core/services/api.service';
import { AuthService } from '../../../core/services/auth.service';
import { NotificationService } from '../../../core/services/notification.service';
import { SettingsService } from '../../../core/services/settings.service';
import { UserCacheService, ResolvedUser } from '../../../core/services/user-cache.service';
import { ChannelWithSubscription } from '../../../core/models';
import { RelativeTimePipe } from '../../../shared/pipes/relative-time.pipe';
import { ChannelSubscribersComponent } from '../channel-subscribers/channel-subscribers.component';

type ChannelTab = 'all' | 'owned' | 'foreign';

@Component({
  selector: 'app-channel-list',
  standalone: true,
  imports: [
    CommonModule,
    DatePipe,
    RouterLink,
    NzTableModule,
    NzButtonModule,
    NzIconModule,
    NzTagModule,
    NzBadgeModule,
    NzEmptyModule,
    NzCardModule,
    NzToolTipModule,
    NzTabsModule,
    NzAlertModule,
    RelativeTimePipe,
    ChannelSubscribersComponent,
  ],
  templateUrl: './channel-list.component.html',
  styleUrl: './channel-list.component.scss'
})
export class ChannelListComponent implements OnInit {
  private apiService = inject(ApiService);
  private authService = inject(AuthService);
  private notification = inject(NotificationService);
  private settingsService = inject(SettingsService);
  private userCacheService = inject(UserCacheService);
  private router = inject(Router);

  allChannels = signal<ChannelWithSubscription[]>([]);
  ownerNames = signal<Map<string, ResolvedUser>>(new Map());
  loading = signal(false);
  expertMode = this.settingsService.expertMode;
  activeTab = signal<ChannelTab>('all');

  channels = computed(() => {
    const userId = this.authService.getUserId();
    const all = this.allChannels();
    const tab = this.activeTab();

    switch (tab) {
      case 'owned':
        return all.filter(c => c.owner_user_id === userId);
      case 'foreign':
        return all.filter(c => c.owner_user_id !== userId);
      default:
        return all;
    }
  });

  ngOnInit(): void {
    this.loadChannels();
  }

  loadChannels(): void {
    const userId = this.authService.getUserId();
    if (!userId) return;

    this.loading.set(true);
    this.apiService.getChannels(userId, 'all_any').subscribe({
      next: (response) => {
        this.allChannels.set(response.channels);
        this.loading.set(false);
        this.resolveOwnerNames(response.channels);
      },
      error: () => {
        this.loading.set(false);
      }
    });
  }

  onTabChange(index: number): void {
    const tabs: ChannelTab[] = ['all', 'owned', 'foreign'];
    this.activeTab.set(tabs[index]);
  }

  getTabDescription(): string | null {
    switch (this.activeTab()) {
      case 'owned':
        return 'Channels that you own and can configure.';
      case 'foreign':
        return 'Channels owned by other users that you are subscribed to.';
      default:
        return null;
    }
  }

  private resolveOwnerNames(channels: ChannelWithSubscription[]): void {
    const uniqueOwnerIds = [...new Set(channels.map(c => c.owner_user_id))];
    for (const ownerId of uniqueOwnerIds) {
      this.userCacheService.resolveUser(ownerId).subscribe(resolved => {
        this.ownerNames.update(map => new Map(map).set(ownerId, resolved));
      });
    }
  }

  getOwnerDisplayName(ownerId: string): string {
    const resolved = this.ownerNames().get(ownerId);
    return resolved?.displayName || ownerId;
  }

  isOwned(channel: ChannelWithSubscription): boolean {
    return channel.owner_user_id === this.authService.getUserId();
  }

  viewChannel(channel: ChannelWithSubscription): void {
    this.router.navigate(['/channels', channel.channel_id]);
  }

  getSubscriptionStatus(channel: ChannelWithSubscription): { label: string; color: string } {
    const userId = this.authService.getUserId();

    if (channel.owner_user_id === userId) {
      if (channel.subscription) {
        return { label: 'Owned & Subscribed', color: 'green' };
      }
      return { label: 'Owned', color: 'blue' };
    }

    if (channel.subscription) {
      if (channel.subscription.confirmed) {
        return { label: 'Subscribed', color: 'green' };
      }
      return { label: 'Pending', color: 'orange' };
    }

    return { label: 'Not Subscribed', color: 'default' };
  }

  toggleSelfSubscription(channel: ChannelWithSubscription, event: Event): void {
    event.stopPropagation();
    const userId = this.authService.getUserId();
    if (!userId) return;

    if (channel.subscription) {
      // Unsubscribe
      this.apiService.deleteSubscription(userId, channel.subscription.subscription_id).subscribe({
        next: () => {
          this.notification.success('Unsubscribed from channel');
          this.loadChannels();
        }
      });
    } else {
      // Subscribe
      this.apiService.createSubscription(userId, { channel_id: channel.channel_id }).subscribe({
        next: () => {
          this.notification.success('Subscribed to channel');
          this.loadChannels();
        }
      });
    }
  }
}