/* ============================================================
   ToolCTRL — Landing Page Server
   Abhängigkeitsfrei (nur Node-Standardbibliothek).
   Liefert /public und nimmt Leads unter POST /api/lead entgegen.
   ============================================================ */

"use strict";

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

const ROOT = __dirname;
const PUBLIC_DIR = path.join(ROOT, "public");
const LEADS_DIR = path.join(ROOT, "leads");
const LEADS_JSON = path.join(LEADS_DIR, "leads.ndjson");
const LEADS_CSV = path.join(LEADS_DIR, "leads.csv");

/* Bevorzugte Ports — der erste freie wird genutzt. */
const PORT_CANDIDATES = [4317, 4318, 4417, 5317, 8317, 0];
const HOST = "127.0.0.1";

const MIME = {
  ".html": "text/html; charset=utf-8",
  ".css": "text/css; charset=utf-8",
  ".js": "text/javascript; charset=utf-8",
  ".svg": "image/svg+xml",
  ".png": "image/png",
  ".jpg": "image/jpeg",
  ".jpeg": "image/jpeg",
  ".ico": "image/x-icon",
  ".json": "application/json; charset=utf-8",
  ".woff2": "font/woff2"
};

/* ---------- Lead-Speicher vorbereiten ---------- */
function ensureLeadStore() {
  if (!fs.existsSync(LEADS_DIR)) fs.mkdirSync(LEADS_DIR, { recursive: true });
  if (!fs.existsSync(LEADS_CSV)) {
    fs.writeFileSync(
      LEADS_CSV,
      "zeitpunkt,name,firma,email,telefon,nachricht,quelle\n",
      "utf8"
    );
  }
}

function csvCell(value) {
  const s = String(value == null ? "" : value);
  return '"' + s.replace(/"/g, '""').replace(/\r?\n/g, " ") + '"';
}

function saveLead(lead) {
  ensureLeadStore();
  fs.appendFileSync(LEADS_JSON, JSON.stringify(lead) + "\n", "utf8");
  const row = [
    lead.zeitpunkt,
    lead.name,
    lead.firma,
    lead.email,
    lead.telefon,
    lead.nachricht,
    lead.quelle
  ]
    .map(csvCell)
    .join(",");
  fs.appendFileSync(LEADS_CSV, row + "\n", "utf8");
}

/* ---------- Statische Dateien ---------- */
function serveStatic(req, res) {
  let urlPath = decodeURIComponent(req.url.split("?")[0]);
  if (urlPath === "/") urlPath = "/index.html";

  /* Path-Traversal verhindern */
  const filePath = path.normalize(path.join(PUBLIC_DIR, urlPath));
  if (!filePath.startsWith(PUBLIC_DIR)) {
    res.writeHead(403).end("Forbidden");
    return;
  }

  fs.stat(filePath, (err, stat) => {
    if (err || !stat.isFile()) {
      res.writeHead(404, { "Content-Type": "text/html; charset=utf-8" });
      res.end("<h1>404</h1><p>Seite nicht gefunden.</p>");
      return;
    }
    const ext = path.extname(filePath).toLowerCase();
    res.writeHead(200, {
      "Content-Type": MIME[ext] || "application/octet-stream",
      "Cache-Control": "no-cache"
    });
    fs.createReadStream(filePath).pipe(res);
  });
}

/* ---------- Lead-Endpunkt ---------- */
function handleLead(req, res) {
  let body = "";
  let tooLarge = false;

  req.on("data", (chunk) => {
    body += chunk;
    if (body.length > 64 * 1024) {
      tooLarge = true;
      req.destroy();
    }
  });

  req.on("end", () => {
    if (tooLarge) return sendJSON(res, 413, { error: "Anfrage zu groß." });

    let data;
    try {
      data = JSON.parse(body || "{}");
    } catch (e) {
      return sendJSON(res, 400, { error: "Ungültiges Format." });
    }

    /* Honeypot — befülltes Feld = Bot. Still mit OK quittieren. */
    if (data.website && String(data.website).trim() !== "") {
      return sendJSON(res, 200, { ok: true });
    }

    const name = String(data.name || "").trim();
    const email = String(data.email || "").trim();
    const nachricht = String(data.nachricht || "").trim();

    if (!name || !email || !nachricht) {
      return sendJSON(res, 400, {
        error: "Bitte Name, E-Mail und Nachricht angeben."
      });
    }
    if (!/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email)) {
      return sendJSON(res, 400, { error: "Bitte eine gültige E-Mail angeben." });
    }

    const lead = {
      zeitpunkt: new Date().toISOString(),
      name: name.slice(0, 200),
      firma: String(data.firma || "").trim().slice(0, 200),
      email: email.slice(0, 200),
      telefon: String(data.telefon || "").trim().slice(0, 80),
      nachricht: nachricht.slice(0, 4000),
      quelle: String(data.quelle || "Landing Page").slice(0, 120)
    };

    try {
      saveLead(lead);
    } catch (e) {
      console.error("[lead] Speichern fehlgeschlagen:", e.message);
      return sendJSON(res, 500, {
        error: "Speichern fehlgeschlagen. Bitte später erneut versuchen."
      });
    }

    console.log(
      "[lead] " + lead.zeitpunkt + " — " + lead.name +
      (lead.firma ? " (" + lead.firma + ")" : "") + " <" + lead.email + ">"
    );
    sendJSON(res, 200, { ok: true });
  });
}

function sendJSON(res, code, obj) {
  res.writeHead(code, { "Content-Type": "application/json; charset=utf-8" });
  res.end(JSON.stringify(obj));
}

/* ---------- Router ---------- */
const server = http.createServer((req, res) => {
  const route = req.url.split("?")[0];

  if (route === "/api/lead") {
    if (req.method !== "POST") {
      return sendJSON(res, 405, { error: "Methode nicht erlaubt." });
    }
    return handleLead(req, res);
  }

  if (req.method !== "GET" && req.method !== "HEAD") {
    res.writeHead(405).end("Method Not Allowed");
    return;
  }
  serveStatic(req, res);
});

/* ---------- Freien Port suchen und starten ---------- */
function listen(candidates) {
  if (candidates.length === 0) {
    console.error("Kein freier Port gefunden.");
    process.exit(1);
  }
  const port = candidates[0];
  server.once("error", (err) => {
    if (err.code === "EADDRINUSE") {
      console.log("Port " + port + " belegt — versuche nächsten …");
      listen(candidates.slice(1));
    } else {
      console.error("Serverfehler:", err.message);
      process.exit(1);
    }
  });
  server.listen(port, HOST, () => {
    const actual = server.address().port;
    ensureLeadStore();
    console.log("");
    console.log("  ToolCTRL — Landing Page läuft");
    console.log("  ----------------------------------------");
    console.log("  URL:    http://" + HOST + ":" + actual);
    console.log("  Leads:  " + LEADS_CSV);
    console.log("          " + LEADS_JSON);
    console.log("  Stop:   Strg + C");
    console.log("");
  });
}

listen(PORT_CANDIDATES);