const { createServer } = require("http");
const next = require("next");
const { Server } = require("socket.io");
const fs = require("fs");
const path = require("path");
const fetch = (...args) => import("node-fetch").then(({ default: fetch }) => fetch(...args));

const dev = process.env.NODE_ENV !== "production";
const app = next({ dev });
const handle = app.getRequestHandler();
const PORT = 3000;

app.prepare().then(() => {
  const server = createServer((req, res) => {
    handle(req, res);
  });

  const io = new Server(server);

  io.on("connection", socket => {
    const { m, mode } = socket.handshake.query;
    const idMap = m;
    const isLiveMode = mode === "live" || mode === "prod";

    let lastStatis = [];

    const fetchData = async () => {
      try {
        let statis;

        if (dev) {
          const mockPath = path.join(process.cwd(), "mockData", "GisLinesStatus.json");
          const jsonStr = fs.readFileSync(mockPath, "utf-8");
          const json = JSON.parse(jsonStr);
          statis = json?.Statis || [];
          console.log("🧪 Mockdaten gelesen");
        } else {
          const fetchUrl = `http://localhost/talas5/ClientData/WebServiceMap.asmx/GisLinesStatus?idMap=${idMap}`;
          const res = await fetch(fetchUrl);
          const text = await res.text();

          if (!text.startsWith("{")) {
            console.error("❌ Webservice liefert kein valides JSON:", text.slice(0, 100));
            return;
          }

          const json = JSON.parse(text);
          statis = json?.Statis || [];
          console.log("📡 Webservice-Daten empfangen");
        }

        const hasChanged =
          statis.length !== lastStatis.length ||
          statis.some((entry, index) => {
            const prev = lastStatis[index];
            return (
              !prev ||
              entry.Modul !== prev.Modul ||
              entry.ModulName !== prev.ModulName ||
              entry.Value !== prev.Value ||
              entry.Level !== prev.Level
            );
          });

        if (hasChanged) {
          lastStatis = statis;
          socket.emit("gisLinesStatusUpdated", statis);
          console.log("✅ Änderung erkannt und gesendet");
        } else {
          console.log("🔁 Keine Änderung festgestellt");
        }
      } catch (error) {
        console.error("❌ Fehler beim Datenabruf:", error.message);
      }
    };

    if (isLiveMode) {
      fetchData();
      const interval = setInterval(fetchData, 5000);
      socket.on("disconnect", () => {
        clearInterval(interval);
        console.log("❌ WebSocket getrennt");
      });
    }
  });

  server.listen(PORT, () => {
    console.log(`🚀 App + Socket.io läuft auf http://localhost:${PORT}`);
  });
});