import { NextRequest, NextResponse } from 'next/server';

export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ path: string[] }> }
) {
  try {
    const resolvedParams = await params;
    const path = resolvedParams.path.join('/');

    // @ts-expect-error - MEDIA is bound via wrangler.toml and available in the Cloudflare context
    const cloudflareContext = (globalThis as Record<string, unknown>)[Symbol.for('__cloudflare-context__')];
    const MEDIA = cloudflareContext?.env?.MEDIA;

    if (!MEDIA) {
      return NextResponse.json(
        { error: 'Media bucket not configured' },
        { status: 500 }
      );
    }

    // Get the object from R2
    const object = await MEDIA.get(path);

    if (!object) {
      return NextResponse.json(
        { error: `File not found: ${path}` },
        { status: 404 }
      );
    }

    // Get range header for video streaming support
    const range = request.headers.get('range');
    
    // Get the full object body to handle range requests properly
    const body = await object.body.arrayBuffer();
    const totalLength = body.byteLength;

    let start = 0;
    let end = totalLength - 1;
    let status = 200;

    if (range) {
      // Extract start and end positions from range header
      const match = range.match(/bytes=(\d+)-(\d+)?/);
      if (match) {
        start = parseInt(match[1], 10);
        end = match[2] ? parseInt(match[2], 10) : end;
        
        // Ensure end is within the bounds
        if (end >= totalLength) {
          end = totalLength - 1;
        }
        
        status = 206; // Partial content
      }
    }

    // Calculate the length for the response
    const contentLength = end - start + 1;
    const slicedBody = body.slice(start, end + 1);

    // Set headers for the response
    const headers = new Headers();
    object.writeHttpMetadata(headers);
    headers.set('etag', object.httpEtag);
    headers.set('cache-control', 'public, max-age=31536000, immutable');
    
    // Add CORS headers to allow video requests from the same origin
    headers.set('access-control-allow-origin', '*');
    headers.set('access-control-allow-headers', 'range, content-type, accept');
    headers.set('access-control-allow-methods', 'GET, HEAD, OPTIONS');
    headers.set('access-control-expose-headers', 'content-range, accept-ranges, content-length, content-encoding');
    
    // Add range response headers if needed
    if (range) {
      headers.set('content-range', `bytes ${start}-${end}/${totalLength}`);
      headers.set('accept-ranges', 'bytes');
    }
    
    headers.set('content-length', contentLength.toString());
    headers.set('content-type', path.endsWith('.mp4') ? 'video/mp4' : object.httpMetadata?.contentType || 'application/octet-stream');

    return new NextResponse(slicedBody, {
      status,
      headers,
    });
  } catch (error) {
    console.error('Error serving media:', error);
    return NextResponse.json(
      { error: 'Failed to serve media file' },
      { status: 500 }
    );
  }
}