/**
 * Horizontal Scroll Nav Component
 * Pill-style category buttons in a horizontal scroller
 */
class HorizontalScrollNav extends HTMLElement {
  constructor() {
    super();
    this.attachShadow({ mode: 'open' });
    this.categories = [
      { id: 'all', label: 'All', active: true },
      { id: 'fiction', label: 'Fiction', active: false },
      { id: 'non-fiction', label: 'Non-Fiction', active: false },
      { id: 'mystery', label: 'Mystery', active: false },
      { id: 'romance', label: 'Romance', active: false },
      { id: 'sci-fi', label: 'Sci-Fi', active: false },
      { id: 'biography', label: 'Biography', active: false },
      { id: 'history', label: 'History', active: false },
    ];
  }

  connectedCallback() {
    this.render();
    this.addEventListeners();
  }

  addEventListeners() {
    const buttons = this.shadowRoot.querySelectorAll('.nav-pill');
    buttons.forEach(button => {
      button.addEventListener('click', (e) => {
        this.setActiveCategory(e.target.dataset.id);
      });
    });
  }

  setActiveCategory(id) {
    this.categories = this.categories.map(cat => ({
      ...cat,
      active: cat.id === id
    }));
    this.render();
    this.addEventListeners();
    
    // Dispatch custom event for parent components
    this.dispatchEvent(new CustomEvent('category-change', {
      detail: { categoryId: id },
      bubbles: true,
      composed: true
    }));
  }

  render() {
    this.shadowRoot.innerHTML = `
      <style>
        :host {
          display: block;
        }

        .nav-container {
          display: flex;
          gap: var(--spacing-sm, 0.5rem);
          overflow-x: auto;
          scrollbar-width: none;
          -ms-overflow-style: none;
          padding: var(--spacing-xs, 0.25rem) 0;
        }

        .nav-container::-webkit-scrollbar {
          display: none;
        }

        .nav-pill {
          flex-shrink: 0;
          padding: var(--spacing-sm, 0.5rem) var(--spacing-md, 1rem);
          font-size: var(--font-size-sm, 0.875rem);
          font-weight: var(--font-weight-medium, 500);
          color: var(--color-text-light, #64748b);
          background-color: var(--color-background-tertiary, #f1f5f9);
          border: none;
          border-radius: var(--radius-full, 9999px);
          cursor: pointer;
          transition: all var(--transition-fast, 150ms ease);
          white-space: nowrap;
        }

        .nav-pill:hover {
          background-color: var(--color-border, #e2e8f0);
        }

        .nav-pill.active {
          color: var(--color-text-inverse, #ffffff);
          background-color: var(--color-primary, #2563eb);
        }

        .nav-pill.active:hover {
          background-color: var(--color-primary-dark, #1d4ed8);
        }
      </style>
      <nav class="nav-container" role="navigation" aria-label="Book categories">
        ${this.categories.map(cat => `
          <button 
            class="nav-pill ${cat.active ? 'active' : ''}" 
            data-id="${cat.id}"
            ${cat.active ? 'aria-current="true"' : ''}
          >
            ${cat.label}
          </button>
        `).join('')}
      </nav>
    `;
  }
}

customElements.define('horizontal-scroll-nav', HorizontalScrollNav);