/**
 * Image Optimizer Web Component
 * Automatically optimizes image loading with lazy loading, placeholders, and responsive images
 */
class ImageOptimizer extends HTMLElement {
  constructor() {
    super();
    this.attachShadow({ mode: 'open' });
  }

  connectedCallback() {
    const src = this.getAttribute('src') || '';
    const alt = this.getAttribute('alt') || '';
    const width = this.getAttribute('width') || '100%';
    const height = this.getAttribute('height') || 'auto';
    const lazy = this.hasAttribute('lazy');
    const placeholder = this.getAttribute('placeholder') || 'https://static.photos/abstract/100x100';
    const category = this.getAttribute('category') || 'general';
    
    // Generate optimized image URL based on static.photos API
    const optimizeURL = (url) => {
      // If it's already a static.photos URL, keep it
      if (url.includes('static.photos')) return url;
      
      // For other URLs, we could add resize parameters if needed
      // For now, just return the original
      return url;
    };

    // Create responsive image sets for different screen sizes
    const generateSrcSet = (baseUrl) => {
      if (!baseUrl.includes('static.photos')) return '';
      
      // Extract dimensions if present
      const dimMatch = baseUrl.match(/\/(\d+)x(\d+)\//);
      if (!dimMatch) return '';
      
      const [_, width, height] = dimMatch;
      const base = baseUrl.replace(`/${width}x${height}/`, '');
      
      // Generate srcset for common breakpoints
      const sizes = [
        { width: 320, height: Math.round(320 * height / width) },
        { width: 640, height: Math.round(640 * height / width) },
        { width: 768, height: Math.round(768 * height / width) },
        { width: 1024, height: Math.round(1024 * height / width) },
        { width: 1280, height: Math.round(1280 * height / width) }
      ];
      
      return sizes.map(size => 
        `${base.replace(/\/\d+x\d+\//, `/${size.width}x${size.height}/`)} ${size.width}w`
      ).join(', ');
    };

    const optimizedSrc = optimizeURL(src);
    const srcset = generateSrcSet(optimizedSrc);

    this.shadowRoot.innerHTML = `
      <style>
        :host {
          display: block;
          position: relative;
          width: ${width};
          height: ${height};
          overflow: hidden;
        }
        
        .image-container {
          position: relative;
          width: 100%;
          height: 100%;
        }
        
        .optimized-image {
          width: 100%;
          height: 100%;
          object-fit: cover;
          transition: opacity 0.3s ease;
          opacity: 0;
        }
        
        .optimized-image.loaded {
          opacity: 1;
        }
        
        .placeholder {
          position: absolute;
          top: 0;
          left: 0;
          width: 100%;
          height: 100%;
          background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
          background-size: 200% 100%;
          animation: loading 1.5s infinite;
          border-radius: inherit;
        }
        
        @keyframes loading {
          0% { background-position: 200% 0; }
          100% { background-position: -200% 0; }
        }
        
        .error-fallback {
          position: absolute;
          top: 0;
          left: 0;
          width: 100%;
          height: 100%;
          background: #f8f9fa;
          display: flex;
          align-items: center;
          justify-content: center;
          color: #6c757d;
          font-size: 14px;
          border-radius: inherit;
        }
        
        .error-fallback i {
          font-size: 24px;
          margin-bottom: 8px;
        }
      </style>
      
      <div class="image-container">
        <div class="placeholder"></div>
        <img 
          class="optimized-image"
          src="${optimizedSrc}"
          ${srcset ? `srcset="${srcset}"` : ''}
          sizes="(max-width: 640px) 100vw, (max-width: 1024px) 50vw, 33vw"
          alt="${alt}"
          ${lazy ? 'loading="lazy"' : ''}
          onload="this.classList.add('loaded')"
          onerror="this.style.display='none'; this.parentNode.querySelector('.error-fallback').style.display='flex';"
        >
        <div class="error-fallback" style="display: none;">
          <div style="text-align: center;">
            <i class="fas fa-image"></i>
            <div>${alt || 'Image'}</div>
          </div>
        </div>
      </div>
    `;
  }

  static get observedAttributes() {
    return ['src', 'alt', 'width', 'height'];
  }

  attributeChangedCallback(name, oldValue, newValue) {
    if (oldValue !== newValue) {
      this.connectedCallback();
    }
  }
}

customElements.define('optimized-image', ImageOptimizer);