import express from "express";
import cors from "cors";
import fs from "fs-extra";
import path from "path";
import { spawn, exec } from "child_process";
import httpProxy from "http-proxy";

const app = express();

/* ================= CONFIGURATION ================= */
const PORT = 7860;
const VITE_PORT = parseInt(process.env.VITE_PORT || "5173");
const PROJECT_DIR = path.join(process.cwd(), "project");
const MASTER_KEY = "AVNEESH_GOD_MODE_777";

const ALLOWED_ORIGINS = [
  "https://avneesh123-autodev-mark2.hf.space",
  "https://avneesh123-autodev-mark2-engine.hf.space",
  "https://avneesh123-autodev-mark2.hf.space/chat",
  "http://localhost:5173",
  "http://localhost:3000",
  "http://127.0.0.1:5173",
];

// ================= SECURE IFRAME LOCK =================
app.use((req, res, next) => {
  res.removeHeader("X-Frame-Options");
  res.setHeader(
    "Content-Security-Policy",
    "frame-ancestors 'self' https://*.hf.space http://localhost:* http://127.0.0.1:*"
  );
  next();
});

// --- Process Managers ---
let viteProcess = null;
let isBooting = false;
let buildRetryCount = 0;
const MAX_RETRIES = 3;
const bgProcesses = new Map();

// ================= PERSISTENT LOCK FILES =================
const FOUNDATION_LOCK = path.join(process.cwd(), ".foundation_lock");
const DEPS_LOCK       = path.join(process.cwd(), ".deps_lock");

/* ================= BINARY FILE EXTENSIONS ================= */
const BINARY_EXTS = [
  ".png", ".jpg", ".jpeg", ".gif", ".webp", ".ico", ".svg",
  ".pdf", ".zip", ".tar", ".gz",
  ".ttf", ".woff", ".woff2", ".otf", ".eot",
  ".mp3", ".mp4", ".wav"
];

function isBinaryFile(filePath) {
  const ext = path.extname(filePath).toLowerCase();
  return BINARY_EXTS.includes(ext);
}

/* ================= IDLE TRACKER ================= */
let lastActivityTime = Date.now();
const IDLE_TIMEOUT = 10 * 60 * 1000;
const IGNORE_ACTIVITY_PATHS = ["/api/logs", "/health", "/api/status"];

function updateActivity(req) {
  if (!IGNORE_ACTIVITY_PATHS.some(p => req.path.startsWith(p))) {
    lastActivityTime = Date.now();
  }
}

setInterval(async () => {
  const idleMs = Date.now() - lastActivityTime;
  if (idleMs > IDLE_TIMEOUT && viteProcess) {
    pushLog(`[IDLE] No activity for ${Math.round(idleMs / 60000)} min — stopping Vite to save resources`, "warning");
    await killVite();
    bgProcesses.forEach((_, id) => killBgProcess(id));
  }
}, 60 * 1000);

/* ================= LOG STREAM ================= */
let logs = [];
let clients = new Set();

function pushLog(message, type = "info") {
  const entry = {
    id: Date.now() + Math.random(),
    time: new Date().toLocaleTimeString(),
    timestamp: Date.now(),
    message,
    type
  };
  logs.push(entry);
  if (logs.length > 500) logs.shift();
  const payload = `data: ${JSON.stringify(entry)}\n\n`;
  clients.forEach(c => {
    try { c.write(payload); } catch { clients.delete(c); }
  });
  console.log(`[${type.toUpperCase()}] ${message}`);
}

/* ================= MIDDLEWARE ================= */
app.use(cors({
  origin: (origin, callback) => {
    if (!origin) return callback(null, true);
    if (ALLOWED_ORIGINS.includes(origin) || origin.endsWith(".hf.space")) return callback(null, true);
    pushLog(`[SECURITY] CORS DENIED — origin: ${origin}`, "error");
    callback(new Error("ACTION_DENIED"));
  },
  credentials: true
}));

app.use(express.json({ limit: "50mb" }));

app.use((err, req, res, next) => {
  if (err.message === "ACTION_DENIED") {
    return res.status(403).json({ error: "ACTION_DENIED", message: "Origin not allowed" });
  }
  next(err);
});

if (!fs.existsSync(PROJECT_DIR)) {
  fs.mkdirSync(PROJECT_DIR, { recursive: true });
}

/* ================= RATE LIMITER & TOKEN SECURITY ================= */
const rateLimitMap = new Map();
function rateLimit(req, res, maxRequests = 30, windowMs = 60000) {
  const ip = req.ip || req.socket.remoteAddress;
  const now = Date.now();
  const windowStart = now - windowMs;
  if (!rateLimitMap.has(ip)) rateLimitMap.set(ip, []);
  const requests = rateLimitMap.get(ip).filter(t => t > windowStart);
  requests.push(now);
  rateLimitMap.set(ip, requests);
  if (requests.length > maxRequests) {
    pushLog(`[RATE LIMIT] IP ${ip} throttled`, "warning");
    res.status(429).json({ error: "TOO_MANY_REQUESTS", retryAfter: 60 });
    return false;
  }
  return true;
}

function verifyToken(req, res) {
  const token = req.body?.token || req.query?.token || req.headers?.["x-api-key"];
  if (token !== MASTER_KEY) {
    pushLog(`[SECURITY] Unauthorized access attempt from ${req.ip}`, "error");
    res.status(403).json({ error: "ACTION_DENIED", message: "Invalid token" });
    return false;
  }
  return true;
}

/* ================= SSE LOG STREAM ================= */
app.get("/api/logs", (req, res) => {
  res.setHeader("Content-Type", "text/event-stream");
  res.setHeader("Cache-Control", "no-cache");
  res.setHeader("Connection", "keep-alive");
  // BUG FIX #1: X-Accel-Buffering missing tha — HF/nginx ke peeche SSE buffer
  // ho jaata tha, logs real-time nahi aate the client tak
  res.setHeader("X-Accel-Buffering", "no");

  const last = parseInt(req.query.last) || 50;
  logs.slice(-last).forEach(l => res.write(`data: ${JSON.stringify(l)}\n\n`));

  // Heartbeat — 30s mein connection alive rakhne ke liye
  const heartbeat = setInterval(() => {
    try { res.write(`: heartbeat\n\n`); } catch { clearInterval(heartbeat); }
  }, 30000);

  clients.add(res);
  req.on("close", () => {
    clients.delete(res);
    clearInterval(heartbeat);
  });
});

/* ================= MULTI-SERVER MANAGER ================= */
function startBgProcess(id, command, port = null) {
  if (bgProcesses.has(id)) {
    pushLog(`[SERVER] Process ${id} is already running`, "warning");
    return false;
  }
  pushLog(`[SERVER] Starting background process [${id}]: ${command}`, "system");
  const proc = spawn(command, {
    cwd: PROJECT_DIR,
    shell: true,
    env: { ...process.env, PORT: port ? String(port) : undefined }
  });
  proc.stdout.on("data", d => pushLog(`[${id.toUpperCase()}] ${d.toString().trim()}`, "info"));
  proc.stderr.on("data", d => pushLog(`[${id.toUpperCase()} ERROR] ${d.toString().trim()}`, "error"));
  proc.on("close", code => {
    pushLog(`[SERVER] Process ${id} stopped (code: ${code})`, "system");
    bgProcesses.delete(id);
  });
  bgProcesses.set(id, { process: proc, command, port });
  return true;
}

function killBgProcess(id) {
  if (!bgProcesses.has(id)) return false;
  const { process: proc } = bgProcesses.get(id);
  proc.kill("SIGKILL");
  bgProcesses.delete(id);
  pushLog(`[SERVER] Killed background process: ${id}`, "warning");
  return true;
}

app.post("/api/process/start", (req, res) => {
  if (!verifyToken(req, res)) return;
  const { id, command, port } = req.body;
  if (!id || !command) return res.status(400).json({ error: "ID and command required" });
  const success = startBgProcess(id, command, port);
  res.json({ success, message: success ? "Process started" : "Process already running" });
});

app.post("/api/process/stop", (req, res) => {
  if (!verifyToken(req, res)) return;
  const { id } = req.body;
  const success = killBgProcess(id);
  res.json({ success, message: success ? "Process stopped" : "Process not found" });
});

/* ================= VITE MANAGER ================= */
function killVite() {
  return new Promise((resolve) => {
    if (viteProcess) {
      pushLog("[SYSTEM] Killing existing Vite process", "system");
      viteProcess.kill("SIGKILL");
      viteProcess = null;
    }
    const killCmd = process.platform === "win32"
      ? `for /f "tokens=5" %a in ('netstat -aon ^| findstr :${VITE_PORT}') do taskkill /F /PID %a`
      : `fuser -k ${VITE_PORT}/tcp`;
    exec(killCmd, () => setTimeout(resolve, 1500));
  });
}

function startVite(forceRestart = false) {
  if (isBooting && !forceRestart) return;
  if (viteProcess && !forceRestart) return;
  if (forceRestart) {
    isBooting = true;
    killVite().then(() => bootVite());
  } else {
    bootVite();
  }
}

function bootVite() {
  pushLog("[SYSTEM] Starting Vite dev server...", "system");
  isBooting = true;
  const nodeModules = path.join(PROJECT_DIR, "node_modules");
  const boot = () => {
    viteProcess = spawn("pnpm", ["run", "dev", "--", "--host", "0.0.0.0", "--port", String(VITE_PORT)], {
      cwd: PROJECT_DIR,
      shell: true,
      env: { ...process.env, FORCE_COLOR: "0" }
    });
    viteProcess.stdout.on("data", d => {
      const msg = d.toString().trim();
      if (!msg) return;
      pushLog("[VITE] " + msg, "info");
      if (msg.includes("Local:") || msg.includes("ready in") || msg.includes("localhost")) {
        isBooting = false;
        buildRetryCount = 0;
        pushLog("[SYSTEM] ✅ Vite is ready!", "success");
      }
    });
    viteProcess.stderr.on("data", d => {
      const msg = d.toString().trim();
      if (!msg) return;
      pushLog("[VITE ERROR] " + msg, "error");
    });
    viteProcess.on("close", (code) => {
      pushLog(`[SYSTEM] Vite stopped (exit code: ${code})`, "system");
      viteProcess = null;
      isBooting = false;
      if (code !== null && code !== 0 && buildRetryCount < MAX_RETRIES) {
        buildRetryCount++;
        pushLog(`[SYSTEM] Auto-restarting Vite (attempt ${buildRetryCount}/${MAX_RETRIES})...`, "warning");
        setTimeout(() => killVite().then(() => bootVite()), 3000);
      }
    });
  };
  if (fs.existsSync(DEPS_LOCK) && fs.existsSync(nodeModules)) {
    pushLog("[INSTALL] ✅ Dependencies locked — skipping install", "success");
    boot();
    return;
  }
  pushLog("[INSTALL] Installing dependencies...", "system");
  const install = spawn("pnpm", ["install"], { cwd: PROJECT_DIR, shell: true });
  install.stdout.on("data", d => pushLog("[INSTALL] " + d.toString().trim(), "info"));
  install.stderr.on("data", d => pushLog("[INSTALL] " + d.toString().trim(), "warning"));
  install.on("close", code => {
    if (code === 0) {
      fs.writeFileSync(DEPS_LOCK, new Date().toISOString());
      pushLog("[INSTALL] ✅ Dependencies installed!", "success");
      boot();
    } else {
      pushLog("[ERROR] ❌ pnpm install failed!", "error");
      isBooting = false;
    }
  });
}

/* ================= STATUS ================= */
app.get("/api/status", (req, res) => {
  res.json({
    ready: !!viteProcess && !isBooting,
    booting: isBooting,
    viteRunning: !!viteProcess,
    activeBackgroundProcesses: Array.from(bgProcesses.keys()),
    uptime: process.uptime(),
    logCount: logs.length
  });
});

/* ================= FILE UPDATE ================= */
app.post("/api/update", async (req, res) => {
  if (!verifyToken(req, res)) return;
  if (!rateLimit(req, res, 20, 60000)) return;
  updateActivity(req);
  const foundationAlreadyWritten = fs.existsSync(FOUNDATION_LOCK);
  const { files, restart = false } = req.body;
  try {
    if (files && Object.keys(files).length > 0) {
      const updatedFiles = [];
      for (const [p, contentObj] of Object.entries(files)) {
        const safePath = path.normalize(p).replace(/^(\.\.[\/\\])+/, "");
        const fp = path.join(PROJECT_DIR, safePath);
        if (!fp.startsWith(PROJECT_DIR)) {
          pushLog(`[SECURITY] Blocked path traversal: ${p}`, "error");
          continue;
        }
        await fs.ensureDir(path.dirname(fp));
        // BUG FIX #2: contentObj null/undefined hone par crash hota tha
        // typeof check se pehle null guard lagao
        const fileContent = contentObj == null
          ? ""
          : typeof contentObj === "string"
            ? contentObj
            : contentObj.content ?? "";
        const isBase64 = contentObj?.isBase64 || isBinaryFile(safePath);
        if (isBase64 && fileContent) {
          await fs.writeFile(fp, Buffer.from(fileContent, "base64"));
        } else {
          await fs.writeFile(fp, fileContent, "utf-8");
        }
        updatedFiles.push(safePath);
      }
      if (!foundationAlreadyWritten) {
        fs.writeFileSync(FOUNDATION_LOCK, new Date().toISOString());
      }
      pushLog(`[FILES] ✅ Updated ${updatedFiles.length} files`, "success");
    }
    if (restart) startVite(true);
    else startVite();
    res.json({ success: true, filesUpdated: Object.keys(files || {}).length });
  } catch (e) {
    pushLog("[ERROR] File update failed: " + e.message, "error");
    res.status(500).json({ error: e.message });
  }
});

/* ================= FILE READ ================= */
app.post("/api/read", async (req, res) => {
  if (!verifyToken(req, res)) return;
  updateActivity(req);
  const { filePath } = req.body;
  try {
    const safePath = path.normalize(filePath).replace(/^(\.\.[\/\\])+/, "");
    const fp = path.join(PROJECT_DIR, safePath);
    if (!fp.startsWith(PROJECT_DIR)) return res.status(403).json({ error: "Path traversal blocked" });
    if (!fs.existsSync(fp)) return res.status(404).json({ error: "File not found" });
    const isBinary = isBinaryFile(safePath);
    const content = isBinary
      ? await fs.readFile(fp, "base64")
      : await fs.readFile(fp, "utf-8");
    res.json({ success: true, content, path: safePath, isBase64: isBinary });
  } catch (e) {
    res.status(500).json({ error: e.message });
  }
});

/* ================= FILE LIST & DELETE ================= */
app.post("/api/files", async (req, res) => {
  if (!verifyToken(req, res)) return;
  updateActivity(req);
  async function walkDir(dir, base = "") {
    const items = [];
    try {
      const entries = await fs.readdir(dir, { withFileTypes: true });
      for (const entry of entries) {
        if (["node_modules", ".git", "dist", ".cache"].includes(entry.name)) continue;
        const relPath = path.join(base, entry.name);
        if (entry.isDirectory()) {
          const children = await walkDir(path.join(dir, entry.name), relPath);
          items.push({ name: entry.name, path: relPath, type: "dir", children });
        } else {
          items.push({ name: entry.name, path: relPath, type: "file" });
        }
      }
    } catch {}
    return items;
  }
  const tree = await walkDir(PROJECT_DIR);
  res.json({ success: true, tree });
});

app.post("/api/delete", async (req, res) => {
  if (!verifyToken(req, res)) return;
  updateActivity(req);
  const { filePath } = req.body;
  try {
    const safePath = path.normalize(filePath).replace(/^(\.\.[\/\\])+/, "");
    const fp = path.join(PROJECT_DIR, safePath);
    if (!fp.startsWith(PROJECT_DIR)) return res.status(403).json({ error: "Path traversal blocked" });
    await fs.remove(fp);
    pushLog(`[FILES] Deleted: ${safePath}`, "warning");
    res.json({ success: true });
  } catch (e) {
    res.status(500).json({ error: e.message });
  }
});

/* ================= COMMAND EXEC ================= */
const BLOCKED_COMMANDS = ["rm -rf /", "mkfs", ":(){ :|:& };:", "shutdown", "reboot", "format"];
app.post("/api/execute", (req, res) => {
  if (!verifyToken(req, res)) return;
  if (!rateLimit(req, res, 15, 60000)) return;
  updateActivity(req);
  const { command, timeout = 30000 } = req.body;
  const isBlocked = BLOCKED_COMMANDS.some(cmd => command.includes(cmd));
  if (isBlocked) {
    pushLog(`[SECURITY] Blocked dangerous command: ${command}`, "error");
    return res.status(403).json({ error: "COMMAND_BLOCKED" });
  }
  pushLog("[TERMINAL] $ " + command, "system");
  const child = exec(command, { cwd: PROJECT_DIR, timeout, maxBuffer: 1024 * 1024 * 10 }, (err, stdout, stderr) => {
    const output = stdout || stderr || err?.message || "";
    const success = !err;
    const exitCode = child.exitCode ?? (err ? 1 : 0);
    if (success) pushLog("[TERMINAL] ✅ Done", "success");
    else pushLog("[TERMINAL] ❌ " + (err?.message || "Command failed"), "error");
    res.json({ success, output, exitCode });
  });
});

/* ================= HEALTH CHECK ================= */
app.get("/health", (req, res) => {
  res.json({
    status: "ok",
    uptime: process.uptime(),
    memory: process.memoryUsage(),
    vite: !!viteProcess,
    timestamp: new Date().toISOString()
  });
});

/* ================= VITE CONTROL & RESET ================= */
app.post("/api/vite/restart", async (req, res) => {
  if (!verifyToken(req, res)) return;
  updateActivity(req);
  pushLog("[SYSTEM] Manual Vite restart requested", "system");
  buildRetryCount = 0;
  startVite(true);
  res.json({ success: true, message: "Vite restart initiated" });
});

app.post("/api/vite/stop", async (req, res) => {
  if (!verifyToken(req, res)) return;
  await killVite();
  res.json({ success: true, message: "Vite stopped" });
});

app.post("/api/reset", async (req, res) => {
  if (!verifyToken(req, res)) return;
  try {
    pushLog("[SYSTEM] Resetting project...", "warning");
    await killVite();
    bgProcesses.forEach((_, id) => killBgProcess(id));
    await fs.remove(PROJECT_DIR);
    fs.mkdirSync(PROJECT_DIR, { recursive: true });
    if (fs.existsSync(FOUNDATION_LOCK)) fs.removeSync(FOUNDATION_LOCK);
    if (fs.existsSync(DEPS_LOCK)) fs.removeSync(DEPS_LOCK);
    buildRetryCount = 0;
    pushLog("[SYSTEM] ✅ Project reset complete", "success");
    res.json({ success: true });
  } catch (e) {
    res.status(500).json({ error: e.message });
  }
});



/* ================= PROXY ================= */
const proxy = httpProxy.createProxyServer({
  target: `http://127.0.0.1:${VITE_PORT}`,
  changeOrigin: true,
  ws: true
});

const PREVIEW_SECRET = "AUTODEV_PREVIEW_777";
const ACCESS_DENIED_PAGE = `<!DOCTYPE html><html><head><title>Access Denied</title><style>body{background:#09090b;color:#fff;font-family:monospace;display:flex;align-items:center;justify-content:center;height:100vh;flex-direction:column;gap:16px;}.title{color:#ef4444;font-size:1.4rem;font-weight:bold;}</style></head><body><div class="title">ACCESS DENIED</div><div>This preview is protected</div></body></html>`;
const BOOTING_PAGE = `<!DOCTYPE html><html><head><title>Booting...</title><style>body{background:#09090b;color:#facc15;font-family:monospace;display:flex;align-items:center;justify-content:center;height:100vh;}</style><script>setTimeout(()=>location.reload(), 2000)</script></head><body>⚡ AutoDev is booting up...</body></html>`;

// BUG FIX #3: proxyRes handler WRONG tha — http-proxy already headers forward
// kar chuka hota hai jab proxyRes fire hota hai, toh wahan set karna useless tha.
// Sahi fix: upar wala app.use iframe middleware engine responses cover karta hai.
// proxyRes handler hata diya.

proxy.on("error", (err, req, res) => {
  if (res && typeof res.writeHead === "function") {
    try {
      res.writeHead(503, { "Content-Type": "text/html" });
      res.end(BOOTING_PAGE);
    } catch {}
  } else if (res && typeof res.destroy === "function") {
    res.destroy();
  }
});

app.use((req, res, next) => {
  if (req.path.startsWith("/api") || req.path === "/health") return next();
  const isRootRequest = req.path === "/" || req.path === "";
  if (isRootRequest) {
    const previewHeader = req.headers["x-autodev-preview"];
    const previewParam  = req.query["__autodev"];
    if (previewHeader !== PREVIEW_SECRET && previewParam !== PREVIEW_SECRET) {
      pushLog(`[SECURITY] Preview blocked — direct access attempt`, "warning");
      return res.status(403).send(ACCESS_DENIED_PAGE);
    }
  }
  updateActivity(req);
  if (!viteProcess && !isBooting) startVite();
  proxy.web(req, res);
});

const server = app.listen(PORT, () => {
  pushLog(`[SYSTEM] AutoDev Engine running on port ${PORT}`, "system");
});

server.on("upgrade", (req, socket, head) => proxy.ws(req, socket, head));

/* ================= GRACEFUL SHUTDOWN ================= */
process.on("SIGTERM", async () => {
  pushLog("[SYSTEM] Shutting down...", "system");
  await killVite();
  bgProcesses.forEach((_, id) => killBgProcess(id));
  process.exit(0);
});

process.on("SIGINT", async () => {
  await killVite();
  bgProcesses.forEach((_, id) => killBgProcess(id));
  process.exit(0);
});

process.on("uncaughtException", err => pushLog("[CRITICAL] Uncaught Exception: " + err.message, "error"));
process.on("unhandledRejection", reason => pushLog("[CRITICAL] Unhandled Rejection: " + reason, "error"));