added notes providing service

import 'package:adnotes/notes/service/notes_providing_service.dart';

import 'package:get_it/get_it.dart';

final get = GetIt.instance;

class IocContainer {

  void setup() {

    get.registerSingleton<NotesProvidingService>(NotesProvidingService());

  }

}

import 'dart:convert';

import 'dart:io';

import 'package:adnotes/common/model/note.dart';

import 'package:path/path.dart' as p;

import 'package:path_provider/path_provider.dart';

const _NOTES_DIRECTORY = 'AdNotesData';

const _NOTES_FILE_NAME = 'ad_notes.json';

class NotesProvidingService {

  NotesProvidingService();

  Future<void> saveNote(Note note) async {

    final file = await _getNotesFile();

    await file.create(recursive: true);

    final notes = await loadNotes();

    notes.add(note);

    final jsonContent = jsonEncode(notes.map((n) => n.toJson()).toList());

    await file.writeAsString(jsonContent);

  }

  Future<void> updateNote(String id, Note note) async {

    final notes = await loadNotes();

    final index = notes.indexWhere((note) => note.id == id);

    if (index != -1) {

      notes[index] = note;

    }

    final presetsJson = jsonEncode(notes.map((e) => e.toJson()).toList());

    final file = await _getNotesFile();

    await file.writeAsString(presetsJson);

  }

  Future<void> deleteNoteById(String id) async {

    final notes = await loadNotes();

    notes.removeWhere((n) => n.id == id);

    final file = await _getNotesFile();

    await file.writeAsString(jsonEncode(notes.map((n) => n.toJson()).toList()));

  }

  Future<List<Note>> loadNotes() async {

    final file = await _getNotesFile();

    if (!await file.exists()) return [];

    final content = await file.readAsString();

    if (content.isEmpty) return [];

    final List<dynamic> jsonList = jsonDecode(content);

    return jsonList.map((json) => Note.fromJson(json)).toList();

  }

  Future<File> _getNotesFile() async {

    final dirPath = await _getNotesDirectoryPath();

    return File(p.join(dirPath, _NOTES_FILE_NAME));

  }

  Future<String> _getNotesDirectoryPath() async {

    final appDocumentsDirectory = await getApplicationDocumentsDirectory();

    return p.join(appDocumentsDirectory.path, _NOTES_DIRECTORY);

  }

}