import { Redis } from "@upstash/redis";

export const runtime = "edge";
const redis = new Redis({
  url: process.env.KV_REST_API_URL!,
  token: process.env.KV_REST_API_TOKEN!,
});

// /api/fcm?topic=<topic>&token=<fcm_token>&action=subscribe|unsubscribe
export async function GET(req: Request) {
  const { searchParams } = new URL(req.url);
  const topic = searchParams.get("topic");
  const token = searchParams.get("token");
  const action = searchParams.get("action"); // "subscribe" | "unsubscribe"

  if (!topic || !token || !action) {
    return new Response(JSON.stringify({ error: "Missing params" }), { status: 400 });
  }
  const key = `fcm-${topic}`;

  if (action === "subscribe") {
    await redis.sadd(key, token);
  } else if (action === "unsubscribe") {
    await redis.srem(key, token);
  } else {
    return new Response(JSON.stringify({ error: "Invalid action" }), { status: 400 });
  }

  return new Response(JSON.stringify({ success: true }), { status: 200 });
}