const fs      = require("fs");
const path    = require("path");
const yaml    = require("js-yaml");
const express = require("express");
const http    = require("http");
const { Server } = require("socket.io");
const cors  = require("cors");
const axios = require("axios");

// ─── Config ───────────────────────────────────────────────────────────────────
const configPath = path.join(__dirname, "config.yml");
const config     = yaml.load(fs.readFileSync(configPath, "utf8"));

const PORT      = config.server?.port || 4000;
const HOSTS     = config.targets?.hosts     || [{url: "http://127.0.0.1:7088", name: "my-server"}];
const ENDPOINTS = config.targets?.endpoints || [];
const TIMEOUT   = config.targets?.timeout   || 120_000;

console.log(`[config] loaded from ${configPath}`);
console.log(`[config] hosts (${HOSTS.length}):`, HOSTS);
console.log(`[config] endpoints:`, ENDPOINTS);

// ─── Express + Socket.io ──────────────────────────────────────────────────────
const app    = express();
const server = http.createServer(app);
const io     = new Server(server, {
  cors: { origin: "*", methods: ["GET", "POST"] },
});

app.use(cors());
app.use(express.json());

// ─── POST /api/parallel-fetch ─────────────────────────────────────────────────
app.post("/api/parallel-fetch", async (req, res) => {
  const { socketId, url, timeout = TIMEOUT } = req.body;

  if (!socketId || !url) {
    return res.status(400).json({ error: "socketId and url are required" });
  }

  const socket = io.sockets.sockets.get(socketId);
  if (!socket) {
    return res.status(400).json({ error: `Socket ${socketId} not found` });
  }

  res.json({ status: "started" });

  const tasks = HOSTS.flatMap((host) =>
    ENDPOINTS.map((endpoint) => ({ host, endpoint }))
  );

  socket.emit("batch:start", { url, total: tasks.length });

  const promises = tasks.map(({ host, endpoint }) => {
    const fullUrl = host.url + endpoint;
    const start   = Date.now();

    return axios({
      method: "POST",
      url: fullUrl,
      headers: { "Content-Type": "application/json" },
      data: { url },
      timeout,
    })
      .then((response) => {
        const elapsed = Date.now() - start;
        console.log(`[OK]    ${host} ${endpoint} (${elapsed}ms)`);
        socket.emit("tool:response", {
          host: host.url,
          serverName: host.name,
          endpoint,
          ok: true,
          status: response.status,
          data: response.data,
          elapsed,
        });
      })
      .catch((err) => {
        const elapsed = Date.now() - start;
        console.log(`[ERROR] ${host} ${endpoint} (${elapsed}ms) — ${err.message}`);
        socket.emit("tool:error", {
          host: host.url, 
          serverName: host.name, 
          endpoint,
          ok: false,
          error: err.message,
          code: err.code || null,
          elapsed,
        });
      });
  });

  Promise.allSettled(promises).then(() => {
    console.log("=== ALL DONE ===");
    socket.emit("batch:done", { url, total: tasks.length });
  });
});

// ─── Health ───────────────────────────────────────────────────────────────────
app.get("/health", (_req, res) =>
  res.json({ ok: true, hosts: HOSTS, endpoints: ENDPOINTS })
);

// ─── Socket lifecycle ─────────────────────────────────────────────────────────
io.on("connection", (socket) => {
  console.log(`[socket] connected    ${socket.id}`);
  socket.on("disconnect", () =>
    console.log(`[socket] disconnected ${socket.id}`)
  );
});

// ─── Start ────────────────────────────────────────────────────────────────────
server.listen(PORT, () =>
  console.log(`Server running on http://localhost:${PORT}`)
);