import {
  Component,
  OnInit,
  ChangeDetectionStrategy,
  ChangeDetectorRef,
} from '@angular/core';
import { CommonModule } from '@angular/common';
import { Router } from '@angular/router';
import { Subject, debounceTime, distinctUntilChanged } from 'rxjs';
import { ImageRecord, ImageService } from '../services/image.service';
import { TagService } from '../services/tag.service';

@Component({
  selector: 'app-library',
  standalone: true,
  imports: [CommonModule],
  changeDetection: ChangeDetectionStrategy.OnPush,
  template: `
    <div class="library">
      <header>
        <h1>Reactbin</h1>
        <button class="upload-btn" (click)="router.navigate(['/upload'])">Upload</button>
      </header>

      <div class="filter-bar">
        <input
          placeholder="Filter by tag…"
          (input)="onTagInput($event)"
          [value]="tagSearch"
        />
        <div class="chips">
          <span *ngFor="let tag of activeFilters" class="chip">
            {{ tag }} <button (click)="removeFilter(tag)">×</button>
          </span>
        </div>
        <ul class="suggestions" *ngIf="suggestions.length">
          <li *ngFor="let s of suggestions" (click)="addFilter(s.name)">{{ s.name }} ({{ s.image_count }})</li>
        </ul>
      </div>

      <div *ngIf="images.length === 0 && !loading" class="empty-state">
        <p>{{ activeFilters.length ? 'No images match these filters.' : 'No images yet. Upload your first!' }}</p>
      </div>

      <div class="grid">
        <div
          *ngFor="let img of images"
          class="image-card"
          (click)="router.navigate(['/images', img.id])"
        >
          <img [src]="imageService.getFileUrl(img.id)" [alt]="img.filename" loading="lazy" />
          <div class="tag-row">
            <span *ngFor="let tag of img.tags" class="chip small">{{ tag }}</span>
          </div>
        </div>
      </div>

      <button *ngIf="hasMore" class="load-more" (click)="loadMore()">Load more</button>
    </div>
  `,
  styles: [`
    .library { max-width: 1200px; margin: 0 auto; padding: 24px 16px; }
    header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 20px; }
    .upload-btn { padding: 8px 20px; background: #4a9eff; color: #000; border: none; border-radius: 6px; cursor: pointer; font-weight: 600; }
    .filter-bar { position: relative; margin-bottom: 24px; }
    .filter-bar input { width: 100%; padding: 10px; background: #1a1a1a; border: 1px solid #444; color: #e0e0e0; border-radius: 6px; }
    .chips { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 8px; }
    .chip { background: #333; padding: 3px 10px; border-radius: 12px; font-size: 0.85rem; display: flex; align-items: center; gap: 4px; }
    .chip.small { font-size: 0.75rem; padding: 2px 8px; }
    .chip button { background: none; border: none; color: #aaa; cursor: pointer; padding: 0; font-size: 1rem; }
    .suggestions { position: absolute; z-index: 10; background: #1a1a1a; border: 1px solid #444; list-style: none; width: 100%; max-height: 200px; overflow-y: auto; border-radius: 0 0 6px 6px; }
    .suggestions li { padding: 8px 12px; cursor: pointer; }
    .suggestions li:hover { background: #2a2a2a; }
    .grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 12px; }
    .image-card { cursor: pointer; background: #1a1a1a; border-radius: 8px; overflow: hidden; }
    .image-card img { width: 100%; height: 160px; object-fit: cover; display: block; }
    .tag-row { padding: 6px; display: flex; flex-wrap: wrap; gap: 4px; }
    .empty-state { text-align: center; padding: 60px 0; color: #666; }
    .load-more { display: block; margin: 24px auto; padding: 10px 32px; background: #2a2a2a; color: #e0e0e0; border: 1px solid #444; border-radius: 6px; cursor: pointer; }
  `],
})
export class LibraryComponent implements OnInit {
  images: ImageRecord[] = [];
  activeFilters: string[] = [];
  tagSearch = '';
  suggestions: { name: string; image_count: number }[] = [];
  loading = false;
  hasMore = false;
  private offset = 0;
  private readonly limit = 50;
  private readonly filterChange$ = new Subject<string>();

  constructor(
    public imageService: ImageService,
    private tagService: TagService,
    public router: Router,
    private cdr: ChangeDetectorRef,
  ) {}

  ngOnInit(): void {
    this.loadImages();
    this.filterChange$.pipe(debounceTime(300), distinctUntilChanged()).subscribe((q) => {
      if (q) {
        this.tagService.list(q, 10).subscribe((r) => {
          this.suggestions = r.items;
          this.cdr.markForCheck();
        });
      } else {
        this.suggestions = [];
        this.cdr.markForCheck();
      }
    });
  }

  onTagInput(event: Event): void {
    const val = (event.target as HTMLInputElement).value;
    this.tagSearch = val;
    this.filterChange$.next(val);
  }

  addFilter(tag: string): void {
    if (!this.activeFilters.includes(tag)) {
      this.activeFilters = [...this.activeFilters, tag];
    }
    this.tagSearch = '';
    this.suggestions = [];
    this.applyFilter(this.activeFilters);
  }

  removeFilter(tag: string): void {
    this.activeFilters = this.activeFilters.filter((t) => t !== tag);
    this.applyFilter(this.activeFilters);
  }

  applyFilter(tags: string[]): void {
    this.activeFilters = tags;
    this.offset = 0;
    this.images = [];
    this.loadImages();
  }

  loadImages(): void {
    this.loading = true;
    this.imageService.list(this.activeFilters, this.limit, this.offset).subscribe((res) => {
      this.images = [...this.images, ...res.items];
      this.offset += res.items.length;
      this.hasMore = this.offset < res.total;
      this.loading = false;
      this.cdr.markForCheck();
    });
  }

  loadMore(): void {
    this.loadImages();
  }
}