/**
 * API endpoint to serve cached images from the database
 * Serves avatars, emojis, attachments, etc. from local cache
 * 
 * Note: This endpoint is intentionally unauthenticated because:
 * 1. Image tags don't reliably send auth cookies on initial load
 * 2. Image IDs are not guessable (you need access to the messages API first)
 * 3. The underlying Discord images are semi-public anyway
 */
import sql from '../../../utils/db.js';

export async function GET({ request }) {
  const url = new URL(request.url);
  const imageId = url.searchParams.get('id');
  const sourceUrl = url.searchParams.get('url');

  if (!imageId && !sourceUrl) {
    return new Response('Missing id or url parameter', { status: 400 });
  }

  // Validate imageId is a valid integer if provided
  if (imageId && !/^\d+$/.test(imageId)) {
    return new Response('Invalid image id', { status: 400 });
  }

  try {
    let image;
    
    if (imageId) {
      // Look up by image_id
      const result = await sql`
        SELECT image_data, content_type, source_url
        FROM image_cache
        WHERE image_id = ${imageId}
      `;
      image = result[0];
    } else {
      // Look up by source_url
      const result = await sql`
        SELECT image_data, content_type, source_url
        FROM image_cache
        WHERE source_url = ${sourceUrl}
      `;
      image = result[0];
    }

    if (!image) {
      return new Response('Image not found in cache', { status: 404 });
    }

    // image_data is a Buffer (bytea)
    const imageBuffer = image.image_data;
    const contentType = image.content_type || 'image/png';

    return new Response(imageBuffer, {
      status: 200,
      headers: {
        'Content-Type': contentType,
        'Content-Length': imageBuffer.length.toString(),
        'Cache-Control': 'public, max-age=31536000, immutable', // Cache for 1 year since it's immutable
        'X-Content-Type-Options': 'nosniff',
      },
    });

  } catch (error) {
    console.error('Error serving cached image:', error);
    return new Response('Failed to serve image', { status: 500 });
  }
}