import { NextRequest } from 'next/server';
import { verifyToken } from '@/lib/auth/jwt';
import { broadcaster } from '@/lib/realtime/broadcaster';

export const runtime = 'nodejs';
export const dynamic = 'force-dynamic';

// Helper to get user from request
function getUserFromRequest(request: NextRequest): { userId: string; email: string } | null {
  const authHeader = request.headers.get('authorization');
  const token = authHeader?.replace('Bearer ', '');

  if (!token) return null;

  try {
    const payload = verifyToken(token);
    return { userId: payload.userId, email: payload.email };
  } catch {
    return null;
  }
}

export async function GET(request: NextRequest) {
  const user = getUserFromRequest(request);

  if (!user) {
    return new Response('Unauthorized', { status: 401 });
  }

  const encoder = new TextEncoder();

  const stream = new ReadableStream({
    start(controller) {
      // Send initial connection message
      controller.enqueue(
        encoder.encode(`data: ${JSON.stringify({ type: 'connected', userId: user.userId })}\n\n`)
      );

      // Subscribe to user's events
      const unsubscribe = broadcaster.subscribe(user.userId, (message) => {
        controller.enqueue(
          encoder.encode(`data: ${JSON.stringify(message)}\n\n`)
        );
      });

      // Also subscribe to global events
      const unsubscribeGlobal = broadcaster.subscribe('global', (message) => {
        controller.enqueue(
          encoder.encode(`data: ${JSON.stringify(message)}\n\n`)
        );
      });

      // Keep connection alive with heartbeat
      const heartbeat = setInterval(() => {
        controller.enqueue(encoder.encode(`: heartbeat\n\n`));
      }, 30000);

      // Cleanup on close
      request.signal.addEventListener('abort', () => {
        clearInterval(heartbeat);
        unsubscribe();
        unsubscribeGlobal();
      });
    },
  });

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