[Save draft locally periodically] Grooming

[hoangdat]

Issue

#3358

Technical

1. Save draft to persistent storage (Hive database)

• Rename all ComposerCache name to LocalDraftEmail

• Create id for LocalDraftEmail:

 final key = TupleKey(
    savedTime,
    accountId.asString,
    userName.value).toString();

• Add DateTime savedTime and String id properties for LocalDraftEmail object. LocalDraftEmail will then be updated to:

class LocalDraftEmail with EquatableMixin {

  final String id;
  final Email email;
  final bool hasRequestReadReceipt;
  final ScreenDisplayMode displayMode;
  final DateTime savedTime;

  LocalDraftEmail(
    this.id,
    this.email,
    this.hasRequestReadReceipt,
    this.displayMode = ScreenDisplayMode.normal,
    this.savedTime,
  );
}

• Create LocalDraftEmailClient class:

class LocalDraftEmailClient extends HiveCacheClient<String> {

  @override
  String get tableName => CachingConstants.localDraftEmailBoxName;
}

• Create LocalDraftEmailDatasource class

abstract class LocalDraftEmailDatasource {
  Future<void> saveLocalDraftEmail(LocalDraftEmail draftEmail);

  Future<List<LocalDraftEmail>> getAllLocalDraftEmail();

  Future<void> removeLocalDraftEmail(String id);
}

• Create TypingStatusController class to manages the typing status and automatically calls the callback function if no typing activity occurs within the specified timeout duration.

import 'dart:async';

class TypingStatusController {
  final Duration timeoutDuration;
  final VoidCallback onCallbackAction;
  Timer? _timer;

  TypingStatusController({
    required this.onCallbackAction,
    this.timeoutDuration = const Duration(seconds: 15),
  });

  /// Call this method when the user starts typing.
  void onUserTyping() {
    _resetTimer();
  }

  /// Reset the timer when the user is typing.
  void _resetTimer() {
    _timer?.cancel();
    _timer = Timer(timeoutDuration, _triggerCallbackAction);
  }

  /// Call the callback function when the timeout occurs.
  void _triggerCallbackAction() {
    onCallbackAction();
  }

  /// Cancel the timer when it's no longer needed (to avoid memory leaks).
  void dispose() {
    _timer?.cancel();
  }
}

2. Displays the local draft email list dialog.

• Sort email list by newest
• Each draft email item has 3 actions: Edit, Save as draft and Delete