const express = require("express");
const bcrypt = require("bcrypt");
const jwt = require("jsonwebtoken");
const multer = require("multer");
const fs = require("fs");
const path = require("path");
const crypto = require("crypto");
const { Pool } = require("pg");

const app = express();
const PORT = Number(process.env.PORT || 3000);
const JWT_SECRET = process.env.JWT_SECRET || "elevator-manager-secret";
const DATABASE_URL = process.env.DATABASE_URL || "postgresql://lift_admin:lift_secret@127.0.0.1:5432/lift_manager";
const SALT_ROUNDS = 10;
const MAX_FILES = 8;
const MAX_FILE_SIZE = 10 * 1024 * 1024;
const COOKIE_NAME = "liftToken";
const PUBLIC_DIR = path.join(__dirname, "public");
const DATA_DIR = path.join(__dirname, "data");
const UPLOAD_DIR = path.join(__dirname, "uploads");
const LEGACY_DATA_FILE = path.join(DATA_DIR, "store.json");

const pool = new Pool({
  connectionString: DATABASE_URL
});

ensureDirectories();

app.use(express.json());
app.use(express.urlencoded({ extended: true }));
app.use(express.static(PUBLIC_DIR));

const storage = multer.diskStorage({
  destination: (_req, _file, cb) => cb(null, UPLOAD_DIR),
  filename: (_req, file, cb) => {
    const extension = path.extname(file.originalname).toLowerCase();
    cb(null, `${Date.now()}-${crypto.randomUUID()}${extension}`);
  }
});

const upload = multer({
  storage,
  limits: {
    fileSize: MAX_FILE_SIZE,
    files: MAX_FILES
  },
  fileFilter: (_req, file, cb) => {
    const isPdf = file.mimetype === "application/pdf" || path.extname(file.originalname).toLowerCase() === ".pdf";
    cb(isPdf ? null : new Error("Csak PDF fájl tölthető fel."), isPdf);
  }
});

app.get("/", (_req, res) => {
  res.sendFile(path.join(PUBLIC_DIR, "index.html"));
});

app.get("/bejelentkezes", requireGuestPage, (_req, res) => {
  res.sendFile(path.join(PUBLIC_DIR, "login.html"));
});

app.get("/regisztracio", requireGuestPage, (_req, res) => {
  res.sendFile(path.join(PUBLIC_DIR, "register.html"));
});

app.get("/alkalmazas", requirePageAuth, (_req, res) => {
  res.sendFile(path.join(PUBLIC_DIR, "app.html"));
});

app.get("/naplo", requirePageAuth, (_req, res) => {
  res.sendFile(path.join(PUBLIC_DIR, "logs.html"));
});

app.get("/api/health", async (_req, res) => {
  const result = await pool.query("SELECT NOW() AS now");
  res.json({ message: "A rendszer működik.", dbTime: result.rows[0].now });
});

app.post("/api/register", async (req, res) => {
  try {
    const username = req.body.username?.trim().toLowerCase();
    const password = req.body.password?.trim();
    const fullName = req.body.fullName?.trim();
    const routeName = req.body.routeName?.trim();

    if (!username || !password || !fullName || !routeName) {
      return res.status(400).json({ message: "Minden regisztrációs mező kötelező." });
    }

    const existingUser = await pool.query("SELECT id FROM users WHERE username = $1", [username]);

    if (existingUser.rowCount) {
      return res.status(409).json({ message: "Ez a felhasználónév már foglalt." });
    }

    const passwordHash = await bcrypt.hash(password, SALT_ROUNDS);

    await pool.query(
      `INSERT INTO users (username, password_hash, full_name, route_name)
       VALUES ($1, $2, $3, $4)`,
      [username, passwordHash, fullName, routeName]
    );

    return res.status(201).json({
      message: "Sikeres regisztráció. Most már bejelentkezhetsz.",
      redirectPath: "/bejelentkezes"
    });
  } catch (_error) {
    return res.status(500).json({ message: "Hiba történt a regisztráció során." });
  }
});

app.post("/api/login", async (req, res) => {
  try {
    const username = req.body.username?.trim().toLowerCase();
    const password = req.body.password?.trim();

    if (!username || !password) {
      return res.status(400).json({ message: "Felhasználónév és jelszó kötelező." });
    }

    const result = await pool.query(
      `SELECT id, username, password_hash, full_name, route_name
       FROM users
       WHERE username = $1`,
      [username]
    );

    if (!result.rowCount) {
      return res.status(401).json({ message: "Hibás bejelentkezési adatok." });
    }

    const user = mapUserRow(result.rows[0]);
    const passwordMatches = await bcrypt.compare(password, result.rows[0].password_hash);

    if (!passwordMatches) {
      return res.status(401).json({ message: "Hibás bejelentkezési adatok." });
    }

    setAuthCookie(res, createToken(user));

    return res.json({
      message: "Sikeres bejelentkezés.",
      redirectPath: "/alkalmazas",
      user
    });
  } catch (_error) {
    return res.status(500).json({ message: "Hiba történt a bejelentkezés során." });
  }
});

app.post("/api/logout", (_req, res) => {
  clearAuthCookie(res);
  return res.json({ message: "Sikeres kijelentkezés.", redirectPath: "/bejelentkezes" });
});

app.get("/api/me", authenticateRequest, (req, res) => {
  res.json({ user: req.user });
});

app.get("/api/dashboard", authenticateRequest, async (req, res) => {
  const result = await pool.query(
    `SELECT id, name, serial_number, location, route_name, last_inspection_date,
            next_inspection_date, inspection_interval_days, last_status, updated_at
     FROM elevators
     WHERE route_name = $1
       AND next_inspection_date IS NOT NULL
       AND next_inspection_date >= CURRENT_DATE
       AND next_inspection_date <= CURRENT_DATE + INTERVAL '7 days'
     ORDER BY next_inspection_date ASC NULLS LAST, id DESC`,
    [req.user.routeName]
  );

  res.json({
    routeName: req.user.routeName,
    elevators: result.rows.map(mapElevatorRow)
  });
});

app.get("/api/elevators", authenticateRequest, async (req, res) => {
  const result = await pool.query(
    `SELECT id, name, serial_number, location, route_name, last_inspection_date,
            next_inspection_date, inspection_interval_days, last_status, updated_at
     FROM elevators
     WHERE route_name = $1
     ORDER BY name ASC, id DESC`,
    [req.user.routeName]
  );

  res.json({
    routeName: req.user.routeName,
    elevators: result.rows.map(mapElevatorRow)
  });
});

app.post("/api/elevators", authenticateRequest, async (req, res) => {
  const payload = normalizeElevatorPayload(req.body, req.user);
  const validationMessage = validateElevatorPayload(payload);

  if (validationMessage) {
    return res.status(400).json({ message: validationMessage });
  }

  const result = await pool.query(
    `INSERT INTO elevators (
       name, serial_number, location, route_name, last_inspection_date,
       next_inspection_date, inspection_interval_days, last_status
     )
     VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
     RETURNING id, name, serial_number, location, route_name, last_inspection_date,
               next_inspection_date, inspection_interval_days, last_status, updated_at`,
    [
      payload.name,
      payload.serialNumber,
      payload.location,
      payload.routeName,
      payload.lastInspectionDate,
      payload.nextInspectionDate,
      payload.inspectionIntervalDays,
      payload.status
    ]
  );

  res.status(201).json({
    message: "Az eszköz sikeresen létre lett hozva.",
    elevator: mapElevatorRow(result.rows[0])
  });
});

app.put("/api/elevators/:elevatorId", authenticateRequest, async (req, res) => {
  const elevatorId = Number(req.params.elevatorId);

  if (!Number.isInteger(elevatorId) || elevatorId <= 0) {
    return res.status(400).json({ message: "Érvénytelen eszközazonosító." });
  }

  const payload = normalizeElevatorPayload(req.body, req.user);
  const validationMessage = validateElevatorPayload(payload);

  if (validationMessage) {
    return res.status(400).json({ message: validationMessage });
  }

  const result = await pool.query(
    `UPDATE elevators
     SET name = $1,
         serial_number = $2,
         location = $3,
         route_name = $4,
         last_inspection_date = $5,
         next_inspection_date = $6,
         inspection_interval_days = $7,
         last_status = $8,
         updated_at = NOW()
     WHERE id = $9 AND route_name = $10
     RETURNING id, name, serial_number, location, route_name, last_inspection_date,
               next_inspection_date, inspection_interval_days, last_status, updated_at`,
    [
      payload.name,
      payload.serialNumber,
      payload.location,
      payload.routeName,
      payload.lastInspectionDate,
      payload.nextInspectionDate,
      payload.inspectionIntervalDays,
      payload.status,
      elevatorId,
      req.user.routeName
    ]
  );

  if (!result.rowCount) {
    return res.status(404).json({ message: "A keresett eszköz nem található." });
  }

  res.json({
    message: "Az eszköz adatai frissültek.",
    elevator: mapElevatorRow(result.rows[0])
  });
});

app.get("/api/logs", authenticateRequest, async (req, res) => {
  const search = req.query.search?.trim().toLowerCase() || "";
  const sortBy = req.query.sortBy?.trim() || "inspectionDateDesc";
  const params = [req.user.routeName];
  let whereClause = "WHERE l.route_name = $1";

  if (search) {
    params.push(`%${search}%`);
    whereClause += ` AND LOWER(CONCAT_WS(' ', l.elevator_name, l.serial_number, l.location, l.route_name, l.technician_name, l.notes, l.status)) LIKE $2`;
  }

  const result = await pool.query(
    `SELECT l.id, l.elevator_id, l.elevator_name, l.serial_number, l.location, l.route_name, l.inspection_date,
            l.next_inspection_date, l.inspection_interval_days, l.status, l.notes,
            l.technician_name, l.created_by_user_id, l.created_at,
            COALESCE(
              JSON_AGG(
                JSON_BUILD_OBJECT(
                  'id', lf.id,
                  'originalName', lf.original_name,
                  'size', lf.size,
                  'downloadPath', '/api/logs/' || l.id || '/files/' || lf.id
                )
                ORDER BY lf.id
              ) FILTER (WHERE lf.id IS NOT NULL),
              '[]'::json
            ) AS files
     FROM logs l
     LEFT JOIN log_files lf ON lf.log_id = l.id
     ${whereClause}
     GROUP BY l.id
     ORDER BY ${buildLogOrder(sortBy)}`,
    params
  );

  res.json({ logs: result.rows.map(mapLogRow) });
});

app.post("/api/logs", authenticateRequest, upload.array("pdfs", MAX_FILES), async (req, res) => {
  const uploadedFiles = req.files || [];
  const client = await pool.connect();

  try {
    const payload = normalizeLogPayload(req.body, req.user);
    const validationMessage = validateLogPayload(payload);

    if (validationMessage) {
      removeUploadedFiles(uploadedFiles);
      return res.status(400).json({ message: validationMessage });
    }

    await client.query("BEGIN");

    let elevatorRow = null;

    if (payload.elevatorId) {
      elevatorRow = await findElevatorById(client, payload.elevatorId, req.user.routeName);

      if (!elevatorRow) {
        removeUploadedFiles(uploadedFiles);
        return res.status(404).json({ message: "A kiválasztott eszköz nem található." });
      }

      const updatedElevator = await client.query(
        `UPDATE elevators
         SET last_inspection_date = $1,
             next_inspection_date = $2,
             inspection_interval_days = $3,
             last_status = $4,
             updated_at = NOW()
         WHERE id = $5
         RETURNING id, name, serial_number, location, route_name, last_inspection_date,
                   next_inspection_date, inspection_interval_days, last_status, updated_at`,
        [
          payload.inspectionDate,
          payload.nextInspectionDate,
          payload.inspectionIntervalDays,
          payload.status,
          payload.elevatorId
        ]
      );

      elevatorRow = updatedElevator.rows[0];
    } else {
      const upsertedElevator = await client.query(
        `INSERT INTO elevators (
           name, serial_number, location, route_name, last_inspection_date,
           next_inspection_date, inspection_interval_days, last_status
         )
         VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
         ON CONFLICT (serial_number)
         DO UPDATE SET
           name = EXCLUDED.name,
           location = EXCLUDED.location,
           route_name = EXCLUDED.route_name,
           last_inspection_date = EXCLUDED.last_inspection_date,
           next_inspection_date = EXCLUDED.next_inspection_date,
           inspection_interval_days = EXCLUDED.inspection_interval_days,
           last_status = EXCLUDED.last_status,
           updated_at = NOW()
         RETURNING id, name, serial_number, location, route_name, last_inspection_date,
                   next_inspection_date, inspection_interval_days, last_status, updated_at`,
        [
          payload.elevatorName,
          payload.serialNumber,
          payload.location,
          payload.routeName,
          payload.inspectionDate,
          payload.nextInspectionDate,
          payload.inspectionIntervalDays,
          payload.status
        ]
      );

      elevatorRow = upsertedElevator.rows[0];
    }

    const logInsert = await client.query(
      `INSERT INTO logs (
         elevator_id, elevator_name, serial_number, location, route_name, inspection_date,
         next_inspection_date, inspection_interval_days, status, notes,
         technician_name, created_by_user_id
       )
       VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12)
       RETURNING id`,
      [
        elevatorRow.id,
        elevatorRow.name,
        elevatorRow.serial_number,
        elevatorRow.location,
        elevatorRow.route_name,
        payload.inspectionDate,
        payload.nextInspectionDate,
        payload.inspectionIntervalDays,
        payload.status,
        payload.notes,
        req.user.fullName,
        req.user.id
      ]
    );

    const logId = logInsert.rows[0].id;

    for (const file of uploadedFiles) {
      const originalName = normalizeUploadedFilename(file.originalname);

      await client.query(
        `INSERT INTO log_files (log_id, original_name, stored_name, size, mime_type)
         VALUES ($1, $2, $3, $4, $5)`,
        [logId, originalName, file.filename, file.size, file.mimetype]
      );
    }

    await client.query("COMMIT");

    res.status(201).json({
      message: "Az ellenőrzési bejegyzés sikeresen mentve lett.",
      log: await fetchLogById(logId)
    });
  } catch (_error) {
    await client.query("ROLLBACK");
    removeUploadedFiles(uploadedFiles);
    res.status(500).json({ message: "Hiba történt a bejegyzés mentése közben." });
  } finally {
    client.release();
  }
});

app.get("/api/logs/:logId/files/:fileId", authenticateRequest, async (req, res) => {
  const logId = Number(req.params.logId);
  const fileId = Number(req.params.fileId);
  const result = await pool.query(
    `SELECT stored_name, original_name
     FROM log_files
     WHERE id = $1 AND log_id = $2`,
    [fileId, logId]
  );

  if (!result.rowCount) {
    return res.status(404).json({ message: "A keresett fájl nem található." });
  }

  const file = result.rows[0];
  const absolutePath = path.join(UPLOAD_DIR, file.stored_name);

  if (!fs.existsSync(absolutePath)) {
    return res.status(404).json({ message: "A fájl már nem érhető el." });
  }

  return res.download(absolutePath, normalizeUploadedFilename(file.original_name));
});

app.use((error, req, res, _next) => {
  removeUploadedFiles(req.files || []);
  const isMulterError = error instanceof multer.MulterError;
  const message = isMulterError
    ? "A PDF feltöltés sikertelen volt. Ellenőrizd a fájlméretet és a darabszámot."
    : error.message || "Váratlan szerverhiba történt.";

  res.status(400).json({ message });
});

startServer();

async function startServer() {
  try {
    await initializeDatabase();
    await migrateLegacyJsonIfNeeded();

    app.listen(PORT, () => {
      console.log(`A liftellenőrzési kezelő fut a(z) http://localhost:${PORT} címen.`);
    });
  } catch (error) {
    console.error("Nem sikerült elindítani a szervert:", error.message);
    process.exit(1);
  }
}

function ensureDirectories() {
  [DATA_DIR, UPLOAD_DIR, PUBLIC_DIR].forEach((directory) => {
    if (!fs.existsSync(directory)) {
      fs.mkdirSync(directory, { recursive: true });
    }
  });
}

async function initializeDatabase() {
  await pool.query(`
    CREATE TABLE IF NOT EXISTS users (
      id SERIAL PRIMARY KEY,
      username TEXT NOT NULL UNIQUE,
      password_hash TEXT NOT NULL,
      full_name TEXT NOT NULL,
      route_name TEXT NOT NULL,
      created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
    );

    CREATE TABLE IF NOT EXISTS elevators (
      id SERIAL PRIMARY KEY,
      name TEXT NOT NULL,
      serial_number TEXT NOT NULL UNIQUE,
      location TEXT NOT NULL,
      route_name TEXT NOT NULL,
      last_inspection_date DATE,
      next_inspection_date DATE,
      inspection_interval_days INTEGER NOT NULL DEFAULT 30,
      last_status TEXT NOT NULL DEFAULT 'rendben',
      updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
    );

    CREATE TABLE IF NOT EXISTS logs (
      id SERIAL PRIMARY KEY,
      elevator_id INTEGER REFERENCES elevators(id) ON DELETE SET NULL,
      elevator_name TEXT NOT NULL,
      serial_number TEXT NOT NULL,
      location TEXT NOT NULL,
      route_name TEXT NOT NULL,
      inspection_date DATE NOT NULL,
      next_inspection_date DATE NOT NULL,
      inspection_interval_days INTEGER NOT NULL DEFAULT 30,
      status TEXT NOT NULL,
      notes TEXT NOT NULL DEFAULT '',
      technician_name TEXT NOT NULL,
      created_by_user_id INTEGER REFERENCES users(id) ON DELETE SET NULL,
      created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
    );

    CREATE TABLE IF NOT EXISTS log_files (
      id SERIAL PRIMARY KEY,
      log_id INTEGER NOT NULL REFERENCES logs(id) ON DELETE CASCADE,
      original_name TEXT NOT NULL,
      stored_name TEXT NOT NULL,
      size INTEGER NOT NULL,
      mime_type TEXT NOT NULL
    );
  `);

  await pool.query(`
    ALTER TABLE logs
    ADD COLUMN IF NOT EXISTS elevator_id INTEGER REFERENCES elevators(id) ON DELETE SET NULL;
  `);
}

async function migrateLegacyJsonIfNeeded() {
  if (!fs.existsSync(LEGACY_DATA_FILE)) {
    return;
  }

  const userCount = await pool.query("SELECT COUNT(*)::int AS count FROM users");

  if (userCount.rows[0].count > 0) {
    return;
  }

  const legacy = JSON.parse(fs.readFileSync(LEGACY_DATA_FILE, "utf-8"));
  const client = await pool.connect();
  const userIdMap = new Map();

  try {
    await client.query("BEGIN");

    for (const user of legacy.users || []) {
      const result = await client.query(
        `INSERT INTO users (username, password_hash, full_name, route_name, created_at)
         VALUES ($1, $2, $3, $4, $5)
         RETURNING id`,
        [user.username, user.passwordHash, user.fullName, user.routeName, user.createdAt || new Date().toISOString()]
      );
      userIdMap.set(user.id, result.rows[0].id);
    }

    for (const elevator of legacy.elevators || []) {
      await client.query(
        `INSERT INTO elevators (
           name, serial_number, location, route_name, last_inspection_date,
           next_inspection_date, inspection_interval_days, last_status, updated_at
         )
         VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)`,
        [
          elevator.name,
          elevator.serialNumber,
          elevator.location,
          elevator.routeName,
          elevator.lastInspectionDate || null,
          elevator.nextInspectionDate || null,
          elevator.inspectionIntervalDays || 30,
          elevator.lastStatus || "rendben",
          elevator.updatedAt || new Date().toISOString()
        ]
      );
    }

    for (const log of legacy.logs || []) {
      const logResult = await client.query(
        `INSERT INTO logs (
           elevator_name, serial_number, location, route_name, inspection_date,
           next_inspection_date, inspection_interval_days, status, notes,
           technician_name, created_by_user_id, created_at
         )
         VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12)
         RETURNING id`,
        [
          log.elevatorName,
          log.serialNumber,
          log.location,
          log.routeName,
          log.inspectionDate,
          log.nextInspectionDate,
          log.inspectionIntervalDays || 30,
          log.status || "rendben",
          log.notes || "",
          log.technicianName,
          userIdMap.get(log.createdByUserId) || null,
          log.createdAt || new Date().toISOString()
        ]
      );

      for (const file of log.files || []) {
        await client.query(
          `INSERT INTO log_files (log_id, original_name, stored_name, size, mime_type)
           VALUES ($1, $2, $3, $4, $5)`,
          [logResult.rows[0].id, file.originalName, file.storedName, file.size || 0, file.mimeType || "application/pdf"]
        );
      }
    }

    await client.query("COMMIT");
  } catch (error) {
    await client.query("ROLLBACK");
    throw error;
  } finally {
    client.release();
  }
}

function createToken(user) {
  return jwt.sign(user, JWT_SECRET, { expiresIn: "8h" });
}

function setAuthCookie(res, token) {
  res.setHeader("Set-Cookie", serializeCookie(COOKIE_NAME, token, {
    httpOnly: true,
    sameSite: "Lax",
    path: "/",
    maxAge: 8 * 60 * 60
  }));
}

function clearAuthCookie(res) {
  res.setHeader("Set-Cookie", serializeCookie(COOKIE_NAME, "", {
    httpOnly: true,
    sameSite: "Lax",
    path: "/",
    maxAge: 0
  }));
}

function serializeCookie(name, value, options) {
  const parts = [`${name}=${encodeURIComponent(value)}`];
  parts.push(`Path=${options.path || "/"}`);
  parts.push(`Max-Age=${options.maxAge || 0}`);
  parts.push("HttpOnly");
  parts.push(`SameSite=${options.sameSite || "Lax"}`);
  return parts.join("; ");
}

function parseCookies(req) {
  const rawCookie = req.headers.cookie || "";

  return rawCookie.split(";").reduce((cookies, entry) => {
    const [name, ...rest] = entry.trim().split("=");

    if (!name) {
      return cookies;
    }

    cookies[name] = decodeURIComponent(rest.join("="));
    return cookies;
  }, {});
}

function getCookieToken(req) {
  return parseCookies(req)[COOKIE_NAME] || "";
}

function getTokenFromRequest(req) {
  const headerToken = req.headers.authorization?.startsWith("Bearer ")
    ? req.headers.authorization.slice(7)
    : "";
  const queryToken = req.query.token?.trim() || "";
  const cookieToken = getCookieToken(req);

  return headerToken || cookieToken || queryToken;
}

function verifyToken(token) {
  try {
    return jwt.verify(token, JWT_SECRET);
  } catch (_error) {
    return null;
  }
}

function requireGuestPage(req, res, next) {
  const token = getCookieToken(req);
  return token && verifyToken(token) ? res.redirect("/alkalmazas") : next();
}

function requirePageAuth(req, res, next) {
  const token = getCookieToken(req);
  const decoded = token ? verifyToken(token) : null;

  if (!decoded) {
    return res.redirect("/bejelentkezes");
  }

  req.user = decoded;
  next();
}

function authenticateRequest(req, res, next) {
  const token = getTokenFromRequest(req);
  const decoded = token ? verifyToken(token) : null;

  if (!decoded) {
    return res.status(401).json({ message: "Bejelentkezés szükséges." });
  }

  req.user = decoded;
  next();
}

function normalizeElevatorPayload(body, user) {
  const inspectionIntervalDays = Number(body.inspectionIntervalDays || 30);

  return {
    name: body.name?.trim(),
    serialNumber: body.serialNumber?.trim().toUpperCase(),
    location: body.location?.trim(),
    routeName: user.routeName,
    lastInspectionDate: body.lastInspectionDate?.trim() || null,
    nextInspectionDate: body.nextInspectionDate?.trim() || null,
    inspectionIntervalDays: Number.isFinite(inspectionIntervalDays) ? inspectionIntervalDays : 30,
    status: body.status?.trim() || "rendben"
  };
}

function validateElevatorPayload(payload) {
  if (!payload.name || !payload.serialNumber || !payload.location) {
    return "Az eszköz neve, gyári száma és helyszíne kötelező.";
  }

  if (!Number.isInteger(payload.inspectionIntervalDays) || payload.inspectionIntervalDays < 1) {
    return "Az ellenőrzési ciklusnak legalább 1 napnak kell lennie.";
  }

  if (!Number.isInteger(payload.inspectionIntervalDays) || payload.inspectionIntervalDays < 1) {
    return "Az ellenőrzési ciklusnak legalább 1 napnak kell lennie.";
  }

  return "";
}

function normalizeLogPayload(body, user) {
  const inspectionIntervalDays = Number(body.inspectionIntervalDays || 30);

  return {
    elevatorId: Number(body.elevatorId || 0) || null,
    elevatorName: body.elevatorName?.trim(),
    serialNumber: body.serialNumber?.trim().toUpperCase(),
    location: body.location?.trim(),
    routeName: body.routeName?.trim() || user.routeName,
    inspectionDate: body.inspectionDate?.trim(),
    nextInspectionDate: body.nextInspectionDate?.trim(),
    inspectionIntervalDays: Number.isFinite(inspectionIntervalDays) ? inspectionIntervalDays : 30,
    status: body.status?.trim() || "rendben",
    notes: body.notes?.trim() || ""
  };
}

function validateLogPayload(payload) {
  if (!payload.elevatorId && (!payload.elevatorName || !payload.serialNumber || !payload.location)) {
    return "A lift neve, gyári száma és helyszíne kötelező.";
  }

  if (!payload.inspectionDate || !payload.nextInspectionDate) {
    return "Az ellenőrzés és a következő ellenőrzés dátuma kötelező.";
  }

  if (!Number.isInteger(payload.inspectionIntervalDays) || payload.inspectionIntervalDays < 1) {
    return "Az ellenőrzési ciklusnak legalább 1 napnak kell lennie.";
  }

  return "";
}

function removeUploadedFiles(files) {
  files.forEach((file) => {
    const absolutePath = path.join(UPLOAD_DIR, file.filename);

    if (fs.existsSync(absolutePath)) {
      fs.unlinkSync(absolutePath);
    }
  });
}

function buildLogOrder(sortBy) {
  const orderMap = {
    inspectionDateAsc: "l.inspection_date ASC, l.id DESC",
    inspectionDateDesc: "l.inspection_date DESC, l.id DESC",
    nextInspectionAsc: "l.next_inspection_date ASC, l.id DESC",
    nextInspectionDesc: "l.next_inspection_date DESC, l.id DESC",
    elevatorNameAsc: "l.elevator_name ASC, l.id DESC",
    statusAsc: "l.status ASC, l.id DESC"
  };

  return orderMap[sortBy] || orderMap.inspectionDateDesc;
}

async function fetchLogById(logId) {
  const result = await pool.query(
    `SELECT l.id, l.elevator_id, l.elevator_name, l.serial_number, l.location, l.route_name, l.inspection_date,
            l.next_inspection_date, l.inspection_interval_days, l.status, l.notes,
            l.technician_name, l.created_by_user_id, l.created_at,
            COALESCE(
              JSON_AGG(
                JSON_BUILD_OBJECT(
                  'id', lf.id,
                  'originalName', lf.original_name,
                  'size', lf.size,
                  'downloadPath', '/api/logs/' || l.id || '/files/' || lf.id
                )
                ORDER BY lf.id
              ) FILTER (WHERE lf.id IS NOT NULL),
              '[]'::json
            ) AS files
     FROM logs l
     LEFT JOIN log_files lf ON lf.log_id = l.id
     WHERE l.id = $1
     GROUP BY l.id`,
    [logId]
  );

  return result.rowCount ? mapLogRow(result.rows[0]) : null;
}

async function findElevatorById(executor, elevatorId, routeName) {
  const result = await executor.query(
    `SELECT id, name, serial_number, location, route_name, last_inspection_date,
            next_inspection_date, inspection_interval_days, last_status, updated_at
     FROM elevators
     WHERE id = $1 AND route_name = $2`,
    [elevatorId, routeName]
  );

  return result.rowCount ? result.rows[0] : null;
}

function mapUserRow(row) {
  return {
    id: row.id,
    username: row.username,
    fullName: row.full_name,
    routeName: row.route_name
  };
}

function mapElevatorRow(row) {
  return {
    id: row.id,
    name: row.name,
    serialNumber: row.serial_number,
    location: row.location,
    routeName: row.route_name,
    lastInspectionDate: row.last_inspection_date,
    nextInspectionDate: row.next_inspection_date,
    inspectionIntervalDays: row.inspection_interval_days,
    lastStatus: row.last_status,
    updatedAt: row.updated_at
  };
}

function mapLogRow(row) {
  return {
    id: row.id,
    elevatorId: row.elevator_id,
    elevatorName: row.elevator_name,
    serialNumber: row.serial_number,
    location: row.location,
    routeName: row.route_name,
    inspectionDate: row.inspection_date,
    nextInspectionDate: row.next_inspection_date,
    inspectionIntervalDays: row.inspection_interval_days,
    status: row.status,
    notes: row.notes,
    technicianName: row.technician_name,
    createdByUserId: row.created_by_user_id,
    createdAt: row.created_at,
    files: Array.isArray(row.files)
      ? row.files.map((file) => ({
          ...file,
          originalName: normalizeUploadedFilename(file.originalName)
        }))
      : []
  };
}

function normalizeUploadedFilename(value) {
  if (!value || !containsLikelyFilenameMojibake(value)) {
    return value;
  }

  const decoded = Buffer.from(value, "latin1").toString("utf8").normalize("NFC");
  return containsReplacementCharacter(decoded) ? value : decoded;
}

function containsLikelyFilenameMojibake(value) {
  return /[\u00C2-\u00C5\u00CC-\u00CF\u00D0-\u00D6\u00D8-\u00DE\u0080-\u009F]/.test(value);
  return /[ÃÅÂ]/.test(value);
}

function containsReplacementCharacter(value) {
  return value.includes("\uFFFD");
}