import { NextRequest } from "next/server";
import Redis from "ioredis";

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

export async function GET(req: NextRequest) {
  const encoder = new TextEncoder();

  const stream = new ReadableStream({
    start(controller) {
      const subscriber = new Redis(process.env.REDIS_URL!);

      subscriber.subscribe("channel:realtime");

      subscriber.on("message", (_channel: string, message: string) => {
        try {
          const data = JSON.parse(message);
          controller.enqueue(
            encoder.encode(
              `event: ${data.type}\ndata: ${JSON.stringify(data)}\n\n`
            )
          );
        } catch {
          // skip malformed messages
        }
      });

      // Send keepalive every 30 seconds
      const keepalive = setInterval(() => {
        try {
          controller.enqueue(encoder.encode(": keepalive\n\n"));
        } catch {
          clearInterval(keepalive);
        }
      }, 30000);

      // Send initial connection event
      controller.enqueue(
        encoder.encode(`event: connected\ndata: {"status":"connected"}\n\n`)
      );

      // Cleanup on close
      req.signal.addEventListener("abort", () => {
        clearInterval(keepalive);
        subscriber.unsubscribe("channel:realtime");
        subscriber.quit();
      });
    },
  });

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