import 'package:file_picker/file_picker.dart';
import 'package:flutter/widgets.dart';

class UploadedFile {
  final PlatformFile file;
  final TextEditingController controller;
  UploadedFile({required this.file})
    : controller = TextEditingController(
        text: file.extension != null
            ? file.name.replaceAll('.${file.extension}', '')
            : file.name,
      );

  String get label => controller.text;
  void dispose() => controller.dispose();
}

class MultiFileUploadService {
  MultiFileUploadService._();
  static final MultiFileUploadService _instance = MultiFileUploadService._();
  factory MultiFileUploadService() => _instance;

  final List<UploadedFile> _files = [];

  // Expose as unmodifiable but containing UploadedFile objects
  List<UploadedFile> get files => List.unmodifiable(_files);

  // Allowed extensions
  static const allowedExtensions = ['pdf', 'png', 'jpg', 'jpeg', 'heic'];

  Future<String?> pickFiles({int maxFileSizeInMB = 3}) async {
    final result = await FilePicker.platform.pickFiles(
      allowMultiple: true,
      withData: true,
      type: FileType.custom,
      allowedExtensions: allowedExtensions,
    );

    if (result != null) {
      for (final pf in result.files) {
        final ext = pf.extension?.toLowerCase() ?? '';
        final sizeInMB = (pf.size / (1024 * 1024));

        if (!allowedExtensions.contains(ext)) {
          return "Unsupported file format: ${pf.name}";
        }
        if (sizeInMB > maxFileSizeInMB) {
          return "File too large (${pf.name}). Max $maxFileSizeInMB MB allowed.";
        }

        // Wrap PlatformFile in our UploadedFile model
        _files.add(UploadedFile(file: pf));
      }
    }
    return null;
  }

  void removeFileAt(int index) {
    if (index >= 0 && index < _files.length) {
      _files[index].dispose();
      _files.removeAt(index);
    }
  }

  void clearAll() {
    for (final f in _files) {
      f.dispose();
    }
    _files.clear();
  }
}