import 'dart:convert';

import 'package:comunic/models/application_preferences.dart';
import 'package:comunic/models/login_tokens.dart';
import 'package:shared_preferences/shared_preferences.dart';

/// Preferences helper
///
/// Stores current account tokens
///
/// @author Pierre HUBERT

enum PreferencesKeyList { LOGIN_TOKENS, ENABLE_DARK_THEME }

const _PreferenceKeysName = {
  PreferencesKeyList.LOGIN_TOKENS: "login_tokens",
  PreferencesKeyList.ENABLE_DARK_THEME: "dark_theme",
};

class PreferencesHelper {
  static PreferencesHelper _instance;

  static Future<PreferencesHelper> getInstance() async {
    if (_instance == null) {
      _instance = PreferencesHelper._();
      await _init();
    }

    return _instance;
  }

  static SharedPreferences _sharedPreferences;

  PreferencesHelper._();

  static Future<void> _init() async {
    _sharedPreferences = await SharedPreferences.getInstance();
  }

  /// Set new login tokens
  Future<void> setLoginTokens(LoginTokens tokens) async {
    await setString(PreferencesKeyList.LOGIN_TOKENS,
        tokens == null ? "null" : tokens.toString());
  }

  /// Get current [LoginTokens]. Returns null if none or in case of failure
  LoginTokens getLoginTokens() {
    try {
      final string = getString(PreferencesKeyList.LOGIN_TOKENS);
      if (string == null || string == "null") return null;
      return LoginTokens.fromJSON(jsonDecode(string));
    } on Exception catch (e) {
      print(e.toString());
      return null;
    }
  }

  Future<bool> setString(PreferencesKeyList key, String value) async {
    return await _sharedPreferences.setString(_PreferenceKeysName[key], value);
  }

  String getString(PreferencesKeyList key) {
    return _sharedPreferences.getString(_PreferenceKeysName[key]);
  }

  Future<bool> setBool(PreferencesKeyList key, bool value) async {
    return await _sharedPreferences.setBool(_PreferenceKeysName[key], value);
  }

  bool getBool(PreferencesKeyList key, {bool alternative = false}) {
    final v = _sharedPreferences.getBool(_PreferenceKeysName[key]);
    return v == null ? alternative : v;
  }

  /// Get all settings as an [ApplicationPreferences] object
  ApplicationPreferences get preferences => ApplicationPreferences(
        enableDarkMode: getBool(PreferencesKeyList.ENABLE_DARK_THEME),
      );

  /// Apply new preferences
  Future<void> setPreferences(ApplicationPreferences preferences) async {
    await setBool(
        PreferencesKeyList.ENABLE_DARK_THEME, preferences.enableDarkMode);
  }
}

PreferencesHelper preferences() {
  if (PreferencesHelper._instance == null)
    throw Exception("Try to get preference before their initialization!");

  return PreferencesHelper._instance;
}