import express from "express";
import { createServer } from "http";
import { Server } from "socket.io";
import path from "path";
import { fileURLToPath } from "url";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

async function startServer() {
  const app = express();
  const httpServer = createServer(app);
  const io = new Server(httpServer, {
    cors: {
      origin: "*",
      methods: ["GET", "POST"],
    },
    // FIX: Force websocket only - prevents the rapid connect/disconnect loop
    // that happens when Socket.io keeps falling back to HTTP polling on HF Spaces
    transports: ["websocket"],
    pingTimeout: 60000,
    pingInterval: 25000,
  });

  const PORT = parseInt(process.env.PORT || "7860");

  let videoQueue: string[] = [];
  let textQueue: string[] = [];
  const partners = new Map<string, string>();
  let activeCount = 0;

  io.on("connection", (socket) => {
    console.log("User connected:", socket.id);

    socket.on("join-queue", ({ type }) => {
      // FIX: If already in queue, do nothing - prevents spam joining on reconnect
      if (videoQueue.includes(socket.id) || textQueue.includes(socket.id)) {
        console.log(`${socket.id} already in queue, ignoring duplicate`);
        socket.emit("waiting");
        return;
      }

      // If already matched with someone, do nothing
      if (partners.has(socket.id)) {
        console.log(`${socket.id} already matched, ignoring join-queue`);
        return;
      }

      console.log(`${socket.id} joining ${type} queue`);
      activeCount++;
      io.emit("online_count", activeCount);

      const queue = type === "video" ? videoQueue : textQueue;

      if (queue.length > 0) {
        const partnerId = queue.shift()!;

        partners.set(socket.id, partnerId);
        partners.set(partnerId, socket.id);

        console.log(`✅ Matched ${socket.id} with ${partnerId}`);

        io.to(socket.id).emit("matched", { partnerId, type, role: "initiator" });
        io.to(partnerId).emit("matched", { partnerId: socket.id, type, role: "receiver" });
      } else {
        queue.push(socket.id);
        socket.emit("waiting");
        console.log(`${socket.id} waiting in ${type} queue (queue size: ${queue.length})`);
      }
    });

    socket.on("send-message", (text) => {
      const partnerId = partners.get(socket.id);
      if (partnerId) {
        io.to(partnerId).emit("receive-message", text);
      }
    });

    socket.on("signal", (data) => {
      const partnerId = partners.get(socket.id);
      if (partnerId) {
        io.to(partnerId).emit("signal", data);
      }
    });

    socket.on("leave-chat", () => {
      handleLeave(socket.id);
    });

    socket.on("disconnect", () => {
      console.log("User disconnected:", socket.id);
      handleLeave(socket.id);
    });

    function handleLeave(socketId: string) {
      const wasActive =
        videoQueue.includes(socketId) ||
        textQueue.includes(socketId) ||
        partners.has(socketId);

      if (wasActive) {
        activeCount = Math.max(0, activeCount - 1);
        io.emit("online_count", activeCount);
      }

      const partnerId = partners.get(socketId);
      if (partnerId) {
        io.to(partnerId).emit("partner-disconnected");
        partners.delete(partnerId);
      }
      partners.delete(socketId);
      videoQueue = videoQueue.filter((id) => id !== socketId);
      textQueue = textQueue.filter((id) => id !== socketId);
    }
  });

  const distPath = path.join(process.cwd(), "dist");
  app.use(express.static(distPath));
  app.get("*", (req, res) => {
    res.sendFile(path.join(distPath, "index.html"));
  });

  httpServer.listen(PORT, "0.0.0.0", () => {
    console.log(`MingleHub server running on port ${PORT}`);
  });
}

startServer();