import { CommonModule } from '@angular/common';
import { ChangeDetectionStrategy, Component, ElementRef, EventEmitter, Input, Output, ViewChild, signal } from '@angular/core';
import { SectionConfig } from '../../shared/models/config';
import { CatalogProductGridComponent } from '../../features/website/catalog/components/product-grid/product-grid.component';
import { ProductCollectionWidgetData } from '../contracts/widget-data.contract';

@Component({
  selector: 'app-product-carousel-widget',
  standalone: true,
  imports: [CommonModule, CatalogProductGridComponent],
  template: `
    <section class="product-carousel-widget">
      @if (data?.title) {
        <h2 class="product-carousel-widget__title">{{ data?.title }}</h2>
      }

      @if (data?.products?.length) {
        @if (isCarousel) {
          <div class="product-carousel-widget__track">
            <button
              type="button"
              class="product-carousel-widget__arrow product-carousel-widget__arrow--prev"
              aria-label="Previous products"
              [disabled]="atStart()"
              (click)="scrollBy(-1)"
            >&larr;</button>

            <div class="product-carousel-widget__scroller" #scroller (scroll)="onScroll()">
              <app-catalog-product-grid [products]="data?.products ?? []" layout="compact" />
            </div>

            <button
              type="button"
              class="product-carousel-widget__arrow product-carousel-widget__arrow--next"
              aria-label="Next products"
              [disabled]="atEnd()"
              (click)="scrollBy(1)"
            >&rarr;</button>
          </div>
        } @else {
          <app-catalog-product-grid [products]="data?.products ?? []" />
        }
      } @else if (data?.emptyMessage) {
        <p class="product-carousel-widget__empty">{{ data?.emptyMessage }}</p>
      }
    </section>
  `,
  styles: [
    `
      .product-carousel-widget { display: grid; gap: var(--space-lg, 24px); }

      .product-carousel-widget__title {
        margin: 0;
        font-size: 1.75rem;
        font-weight: 700;
        color: var(--text-primary, #1e3c38);
      }

      .product-carousel-widget__empty { margin: 0; color: var(--text-secondary, #667a77); }

      .product-carousel-widget__track {
        display: flex;
        align-items: center;
        gap: 8px;
        min-width: 0;
      }

      .product-carousel-widget__scroller {
        flex: 1;
        min-width: 0;
        overflow-x: auto;
        scroll-behavior: smooth;
        scrollbar-width: none;

        &::-webkit-scrollbar { display: none; }

        ::ng-deep .catalog-product-grid {
          display: flex;
          flex-wrap: nowrap;
          gap: var(--space-md, 16px);
        }

        ::ng-deep .catalog-product-shell {
          flex: 0 0 auto;
          width: 220px;
        }
      }

      .product-carousel-widget__arrow {
        flex-shrink: 0;
        width: 40px;
        height: 40px;
        border-radius: 50%;
        border: 1px solid var(--border-color, #d3dad9);
        background: #fff;
        color: var(--text-primary, #1e3c38);
        cursor: pointer;
        font-size: 1rem;

        &:hover:not(:disabled) { background: var(--primary-color, #497671); color: #fff; }
        &:disabled { opacity: 0.35; cursor: default; }
        &:focus-visible { outline: 2px solid var(--primary-color, #497671); outline-offset: 2px; }
      }
    `
  ],
  changeDetection: ChangeDetectionStrategy.OnPush
})
export class ProductCarouselWidgetComponent {
  @Input() section: SectionConfig | null = null;
  @Input() data: ProductCollectionWidgetData | null = null;

  @Output() productSelected = new EventEmitter<unknown>();

  @ViewChild('scroller') private scroller?: ElementRef<HTMLDivElement>;

  readonly atStart = signal(true);
  readonly atEnd = signal(false);

  get isCarousel(): boolean {
    return this.section?.layout?.strategy === 'carousel';
  }

  scrollBy(direction: -1 | 1): void {
    const el = this.scroller?.nativeElement;
    if (!el) {
      return;
    }
    el.scrollBy({ left: direction * el.clientWidth * 0.8, behavior: 'smooth' });
  }

  onScroll(): void {
    const el = this.scroller?.nativeElement;
    if (!el) {
      return;
    }
    this.atStart.set(el.scrollLeft <= 4);
    this.atEnd.set(el.scrollLeft + el.clientWidth >= el.scrollWidth - 4);
  }
}