const fsPromises = require('fs').promises;
const fs = require('fs');
const path = require('path');
const XLSX = require('xlsx');

class FileManager {
  /**
   * Moves a file from sourcePath to destinationPath.
   * @param {string} sourcePath - Full path to the source file.
   * @param {string} destinationPath - Destination directory or full file path.
   */
  async moveFile(sourcePath, destinationPath) {
    try {
      const destinationStat = await fsPromises.lstat(destinationPath).catch(() => null);
      const isDirectory = destinationStat && destinationStat.isDirectory();

      const finalDestination = isDirectory
        ? path.join(destinationPath, path.basename(sourcePath))
        : destinationPath;

      await fsPromises.rename(sourcePath, finalDestination);

    } catch (error) {
      throw error;
    }
  }

  readExcelFile(filePath) {
   
    if (!fs.existsSync(filePath)) {
      throw new Error(`Datei nicht gefunden: ${filePath}`);
    }

    const ext = path.extname(filePath).toLowerCase();
    if (ext !== '.xlsx' && ext !== '.xls') {
      throw new Error(`Ungültiger Dateityp: ${ext}`);
    }

    const workbook = XLSX.readFile(filePath);
    const sheetName = workbook.SheetNames[0];
    const worksheet = workbook.Sheets[sheetName];
    const data = XLSX.utils.sheet_to_json(worksheet, { defval: null });

    return data;    
  }

   static async readJson(filePath) {
        try {
            const data = await fsPromises.readFile(filePath, 'utf-8');
            return JSON.parse(data);
        } catch (error) {
            throw new Error(`Fehler beim Lesen der JSON-Datei: ${error.message}`);
        }
    }

    static async writeJson(filePath, data) {
        try {
            const jsonString = JSON.stringify(data, null, 4); // schön formatiert
            await fsPromises.writeFile(filePath, jsonString, 'utf-8');
        } catch (error) {
            throw new Error(`Fehler beim Schreiben der JSON-Datei: ${error.message}`);
        }
    }

    static async copyFile(sourcePath, destinationPath) {
        try {
            await fsPromises.copyFile(sourcePath, destinationPath);
            //console.log(`Datei erfolgreich kopiert von ${sourcePath} nach ${destinationPath}`);
        } catch (error) {
            throw new Error(`Fehler beim Kopieren der Datei: ${error.message}`);
        }
    }

    static convertDateExcel (excelDate) {
      // Get the number of milliseconds from Unix epoch.
      const unixTime = (excelDate - 25569) * 86400 * 1000;
      return new Date(unixTime);
    }


}

module.exports = FileManager;