import { NextRequest } from 'next/server';

const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:8000';

export const dynamic = 'force-dynamic';

export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ jobId: string }> }
) {
  const { jobId } = await params;
  const encoder = new TextEncoder();

  const stream = new ReadableStream({
    async start(controller) {
      try {
        const response = await fetch(`${API_BASE_URL}/jobs/${jobId}/stream`, {
          headers: {
            'Accept': 'text/event-stream',
            'Cache-Control': 'no-cache',
          },
        });

        if (!response.ok || !response.body) {
          controller.enqueue(encoder.encode(`event: error\ndata: {"error": "Failed to connect to backend"}\n\n`));
          controller.close();
          return;
        }

        const reader = response.body.getReader();

        while (true) {
          const { done, value } = await reader.read();
          if (done) {
            break;
          }
          // Forward the SSE data as-is
          controller.enqueue(value);
        }
      } catch (error) {
        console.error('SSE stream error:', error);
        controller.enqueue(encoder.encode(`event: error\ndata: {"error": "Stream connection failed"}\n\n`));
      } finally {
        controller.close();
      }
    },
  });

  return new Response(stream, {
    headers: {
      'Content-Type': 'text/event-stream',
      'Cache-Control': 'no-cache, no-transform',
      'Connection': 'keep-alive',
      'X-Accel-Buffering': 'no',
    },
  });
}