import 'dart:io';
import 'dart:convert'; // Added to ensure correct UTF-8 encoding
import 'package:flutter/foundation.dart';
import 'package:archive/archive_io.dart';
import 'package:path_provider/path_provider.dart';
import 'package:path/path.dart' as p;

/// A dedicated service to handle the creation of ZIP archives for FTP submission.
class ZippingService {
  /// Creates multiple JSON files from a map of data and zips them into a single archive.
  /// The map keys will be the filenames (e.g., 'db.json', 'form_data.json').
  /// The map values should be the JSON string content for each file.
  Future<File?> createDataZip({
    required Map<String, String> jsonDataMap,
    required String baseFileName,
    Directory? destinationDir,
  }) async {
    try {
      final targetDir = destinationDir ?? await getTemporaryDirectory();
      // Ensure the target directory exists before creating the file
      if (!await targetDir.exists()) {
        await targetDir.create(recursive: true);
      }
      final zipFilePath = p.join(targetDir.path, '$baseFileName.zip');
      final encoder = ZipFileEncoder();
      encoder.create(zipFilePath);

      debugPrint("Creating data ZIP at: $zipFilePath");

      for (var entry in jsonDataMap.entries) {
        final fileName = entry.key;
        final jsonContent = entry.value;

        // --- MODIFIED: Ensure UTF-8 encoding ---
        // 1. Encode the string content into UTF-8 bytes
        final utf8Bytes = utf8.encode(jsonContent);

        // 2. Use the UTF-8 bytes and their correct length for the archive
        //    (This replaces the original: jsonContent.length, jsonContent.codeUnits)
        final archiveFile = ArchiveFile(fileName, utf8Bytes.length, utf8Bytes);
        // --- END MODIFICATION ---

        encoder.addArchiveFile(archiveFile);

        debugPrint("Added $fileName to data ZIP.");
      }

      encoder.close();
      debugPrint("Data ZIP creation complete.");
      return File(zipFilePath);
    } catch (e) {
      debugPrint("Error creating data ZIP file: $e");
      return null;
    }
  }

  /// Creates a ZIP file from a list of image files.
  Future<File?> createImageZip({
    required List<File> imageFiles,
    required String baseFileName,
    Directory? destinationDir, // ADDED: New optional parameter
  }) async {
    if (imageFiles.isEmpty) {
      debugPrint("No images provided to create an image ZIP.");
      return null;
    }

    try {
      final targetDir = destinationDir ?? await getTemporaryDirectory();
      // Ensure the target directory exists before creating the file
      if (!await targetDir.exists()) {
        await targetDir.create(recursive: true);
      }
      final zipFilePath = p.join(targetDir.path, '${baseFileName}_img.zip');
      final encoder = ZipFileEncoder();
      encoder.create(zipFilePath);

      debugPrint("Creating image ZIP at: $zipFilePath");

      for (var imageFile in imageFiles) {
        if (await imageFile.exists()) {
          await encoder.addFile(imageFile);
          debugPrint("Added ${p.basename(imageFile.path)} to image ZIP.");
        } else {
          debugPrint("Skipping non-existent file: ${imageFile.path}");
        }
      }

      encoder.close();
      debugPrint("Image ZIP creation complete.");
      return File(zipFilePath);
    } catch (e) {
      debugPrint("Error creating image ZIP file: $e");
      return null;
    }
  }
}