/**
 * Minimaler lokaler HTTPS-Server für das Starface Outlook Sync Add-in.
 * Liefert nur statische Dateien aus dem webroot-Verzeichnis aus.
 * Wird als Windows-Dienst oder Scheduled Task ausgeführt.
 */

const https = require("https");
const http = require("http");
const fs = require("fs");
const path = require("path");
const url = require("url");

// Konfiguration aus config.json laden
const configPath = path.join(__dirname, "config.json");
if (!fs.existsSync(configPath)) {
  console.error("config.json nicht gefunden:", configPath);
  process.exit(1);
}

const config = JSON.parse(fs.readFileSync(configPath, "utf-8"));
const PORT = config.port || 444;
const WEBROOT = path.join(__dirname, "webroot");
const CERT_DIR = path.join(__dirname, "certs");

// MIME-Types
const MIME_TYPES = {
  ".html": "text/html; charset=utf-8",
  ".js": "application/javascript; charset=utf-8",
  ".css": "text/css; charset=utf-8",
  ".json": "application/json; charset=utf-8",
  ".png": "image/png",
  ".jpg": "image/jpeg",
  ".svg": "image/svg+xml",
  ".ico": "image/x-icon",
  ".xml": "application/xml; charset=utf-8",
};

function getMimeType(filePath) {
  const ext = path.extname(filePath).toLowerCase();
  return MIME_TYPES[ext] || "application/octet-stream";
}

function handleRequest(req, res) {
  // CORS-Header für Office Add-in
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader("Access-Control-Allow-Methods", "GET, OPTIONS");
  res.setHeader("Access-Control-Allow-Headers", "Content-Type");

  if (req.method === "OPTIONS") {
    res.writeHead(204);
    res.end();
    return;
  }

  if (req.method !== "GET") {
    res.writeHead(405, { "Content-Type": "text/plain" });
    res.end("Method Not Allowed");
    return;
  }

  // URL parsen und Pfad bereinigen
  const parsedUrl = url.parse(req.url);
  let filePath = decodeURIComponent(parsedUrl.pathname || "/");

  // Directory index
  if (filePath === "/" || filePath === "") {
    filePath = "/taskpane.html";
  }

  // Pfad-Traversal verhindern
  const safePath = path.normalize(filePath).replace(/^(\.\.[\/\\])+/, "");
  const fullPath = path.join(WEBROOT, safePath);

  // Sicherstellen, dass der Pfad innerhalb des webroot liegt
  if (!fullPath.startsWith(WEBROOT)) {
    res.writeHead(403, { "Content-Type": "text/plain" });
    res.end("Forbidden");
    return;
  }

  // Datei ausliefern
  fs.stat(fullPath, (err, stats) => {
    if (err || !stats.isFile()) {
      res.writeHead(404, { "Content-Type": "text/plain" });
      res.end("Not Found: " + safePath);
      return;
    }

    const mimeType = getMimeType(fullPath);
    res.writeHead(200, {
      "Content-Type": mimeType,
      "Cache-Control": "no-cache",
    });

    const stream = fs.createReadStream(fullPath);
    stream.pipe(res);
    stream.on("error", () => {
      res.writeHead(500, { "Content-Type": "text/plain" });
      res.end("Internal Server Error");
    });
  });
}

// Zertifikate laden und HTTPS-Server starten
const certFile = path.join(CERT_DIR, "localhost.crt");
const keyFile = path.join(CERT_DIR, "localhost.key");

if (!fs.existsSync(certFile) || !fs.existsSync(keyFile)) {
  console.error("Zertifikate nicht gefunden in:", CERT_DIR);
  console.error("Bitte zuerst setup.ps1 ausführen.");
  process.exit(1);
}

const serverOptions = {
  cert: fs.readFileSync(certFile),
  key: fs.readFileSync(keyFile),
};

const server = https.createServer(serverOptions, handleRequest);

server.listen(PORT, "127.0.0.1", () => {
  console.log(`Starface Outlook Sync - Lokaler Server`);
  console.log(`Läuft auf: https://localhost:${PORT}`);
  console.log(`Webroot:   ${WEBROOT}`);
  console.log(`PID:       ${process.pid}`);
});

server.on("error", (err) => {
  if (err.code === "EADDRINUSE") {
    console.error(`Port ${PORT} ist bereits belegt.`);
    console.error("Bitte anderen Port in config.json wählen.");
  } else {
    console.error("Server-Fehler:", err.message);
  }
  process.exit(1);
});

// Graceful Shutdown
process.on("SIGINT", () => {
  console.log("Server wird beendet...");
  server.close(() => process.exit(0));
});
process.on("SIGTERM", () => {
  console.log("Server wird beendet...");
  server.close(() => process.exit(0));
});