import multer from 'multer';
import path from 'path';
import { Request } from 'express';
import { env } from '../config/env';

// Povolené MIME typy
const ALLOWED_MIME_TYPES = [
  // Obrázky
  'image/jpeg',
  'image/png',
  'image/gif',
  'image/webp',
  // Dokumenty
  'application/pdf',
  'application/msword',
  'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
  'application/vnd.ms-excel',
  'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
  'text/plain',
  'text/csv',
];

// Povolené prípony
const ALLOWED_EXTENSIONS = [
  '.jpg', '.jpeg', '.png', '.gif', '.webp',
  '.pdf', '.doc', '.docx', '.xls', '.xlsx',
  '.txt', '.csv',
];

// Maximálna veľkosť súboru (default 10MB)
const MAX_FILE_SIZE = parseInt(process.env.MAX_FILE_SIZE || '10485760', 10);

// Storage konfigurácia
const storage = multer.diskStorage({
  destination: (req: Request, _file, cb) => {
    // Určenie cieľového priečinka podľa entity type
    const entityType = req.params.entityType || req.body.entityType || 'general';
    const uploadPath = path.join(env.UPLOAD_DIR || 'uploads', entityType);
    cb(null, uploadPath);
  },
  filename: (_req, file, cb) => {
    // Generovanie unikátneho názvu: timestamp-random.extension
    const uniqueSuffix = `${Date.now()}-${Math.round(Math.random() * 1e9)}`;
    const ext = path.extname(file.originalname).toLowerCase();
    cb(null, `${uniqueSuffix}${ext}`);
  },
});

// File filter
const fileFilter = (
  _req: Request,
  file: Express.Multer.File,
  cb: multer.FileFilterCallback
) => {
  const ext = path.extname(file.originalname).toLowerCase();

  // Kontrola MIME typu
  if (!ALLOWED_MIME_TYPES.includes(file.mimetype)) {
    cb(new Error(`Nepodporovaný typ súboru: ${file.mimetype}`));
    return;
  }

  // Kontrola prípony
  if (!ALLOWED_EXTENSIONS.includes(ext)) {
    cb(new Error(`Nepodporovaná prípona súboru: ${ext}`));
    return;
  }

  cb(null, true);
};

// Základná multer inštancia
export const upload = multer({
  storage,
  fileFilter,
  limits: {
    fileSize: MAX_FILE_SIZE,
    files: 10, // Max počet súborov naraz
  },
});

// Pre-configured uploaders pre rôzne entity
export const equipmentUpload = multer({
  storage: multer.diskStorage({
    destination: (_req, _file, cb) => {
      cb(null, path.join(env.UPLOAD_DIR || 'uploads', 'equipment'));
    },
    filename: (_req, file, cb) => {
      const uniqueSuffix = `${Date.now()}-${Math.round(Math.random() * 1e9)}`;
      const ext = path.extname(file.originalname).toLowerCase();
      cb(null, `${uniqueSuffix}${ext}`);
    },
  }),
  fileFilter,
  limits: {
    fileSize: MAX_FILE_SIZE,
    files: 10,
  },
});

export const rmaUpload = multer({
  storage: multer.diskStorage({
    destination: (_req, _file, cb) => {
      cb(null, path.join(env.UPLOAD_DIR || 'uploads', 'rma'));
    },
    filename: (_req, file, cb) => {
      const uniqueSuffix = `${Date.now()}-${Math.round(Math.random() * 1e9)}`;
      const ext = path.extname(file.originalname).toLowerCase();
      cb(null, `${uniqueSuffix}${ext}`);
    },
  }),
  fileFilter,
  limits: {
    fileSize: MAX_FILE_SIZE,
    files: 10,
  },
});

// Pending upload - for files before entity is created
export const pendingUpload = multer({
  storage: multer.diskStorage({
    destination: (_req, _file, cb) => {
      cb(null, path.join(env.UPLOAD_DIR || 'uploads', 'pending'));
    },
    filename: (_req, file, cb) => {
      const uniqueSuffix = `${Date.now()}-${Math.round(Math.random() * 1e9)}`;
      const ext = path.extname(file.originalname).toLowerCase();
      cb(null, `${uniqueSuffix}${ext}`);
    },
  }),
  fileFilter,
  limits: {
    fileSize: MAX_FILE_SIZE,
    files: 10,
  },
});

export const taskUpload = multer({
  storage: multer.diskStorage({
    destination: (_req, _file, cb) => {
      cb(null, path.join(env.UPLOAD_DIR || 'uploads', 'task'));
    },
    filename: (_req, file, cb) => {
      const uniqueSuffix = `${Date.now()}-${Math.round(Math.random() * 1e9)}`;
      const ext = path.extname(file.originalname).toLowerCase();
      cb(null, `${uniqueSuffix}${ext}`);
    },
  }),
  fileFilter,
  limits: {
    fileSize: MAX_FILE_SIZE,
    files: 10,
  },
});

// Helper pre získanie URL súboru
export const getFileUrl = (entityType: string, filename: string): string => {
  return `/uploads/${entityType}/${filename}`;
};

// Helper pre získanie cesty súboru
export const getFilePath = (entityType: string, filename: string): string => {
  return path.join(env.UPLOAD_DIR || 'uploads', entityType, filename);
};