From 6eda69fcc5d49f5f2fecdecf9d0bd3a881118511 Mon Sep 17 00:00:00 2001
From: "nikbel2004@outlook.com" <nikbel2004@outlook.com>
Date: Wed, 18 Dec 2024 17:22:07 +0400
Subject: [PATCH] Components: Implementation of Search Debounces

---
 lib/components/utils/debounce.dart            | 22 +++++++++++++
 .../bloc/candy_bloc/candy_bloc.dart           | 31 +++++++++++++++++++
 .../bloc/candy_bloc/candy_event.dart          | 10 ++++++
 .../bloc/candy_bloc/candy_state.dart          | 25 +++++++++++++++
 .../pages/home_page/candy_page.dart           |  1 -
 5 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 lib/components/utils/debounce.dart
 create mode 100644 lib/presentation/bloc/candy_bloc/candy_bloc.dart
 create mode 100644 lib/presentation/bloc/candy_bloc/candy_event.dart
 create mode 100644 lib/presentation/bloc/candy_bloc/candy_state.dart

diff --git a/lib/components/utils/debounce.dart b/lib/components/utils/debounce.dart
new file mode 100644
index 0000000..40f6ac0
--- /dev/null
+++ b/lib/components/utils/debounce.dart
@@ -0,0 +1,22 @@
+import 'dart:async';
+import 'dart:ui';
+
+class Debounce {
+  // Фабричный конструктор, возвращающий экземпляр класса Debounce. Паттерн Singleton
+  factory Debounce() => _instance;
+
+  // Приватный конструктор (Не даёт создание класса извне)
+  Debounce._();
+
+  // Статический экземпляр класса
+  static final Debounce _instance = Debounce._();
+
+  static Timer? _timer;
+
+  // Статический метод, где action функция, совершающая действие, а delay совершает задержку
+  static void run(
+      {required VoidCallback action, Duration delay = const Duration(milliseconds: 500)}) {
+    _timer?.cancel();
+    _timer = Timer(delay, action);
+  }
+}
diff --git a/lib/presentation/bloc/candy_bloc/candy_bloc.dart b/lib/presentation/bloc/candy_bloc/candy_bloc.dart
new file mode 100644
index 0000000..d042026
--- /dev/null
+++ b/lib/presentation/bloc/candy_bloc/candy_bloc.dart
@@ -0,0 +1,31 @@
+import 'package:candystore/data/repositories/candy_repository.dart';
+import 'package:candystore/presentation/bloc/candy_bloc/candy_event.dart';
+import 'package:candystore/presentation/bloc/candy_bloc/candy_state.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+
+class CandyBloc extends Bloc<CandyEvent, CandyState> {
+  final CandyRepository repository;
+
+  CandyBloc(this.repository) : super(const CandyState()) {
+    on<CandyLoadDataEvent>(_onLoadData);
+  }
+
+  Future<void> _onLoadData(CandyLoadDataEvent event, Emitter<CandyState> emit) async {
+    if (event.nextPage == null) {
+      emit(state.copyWith(isLoading: true));
+    } else {
+      emit(state.copyWith(isPaginationLoading: true));
+    }
+
+    String? error;
+
+    final data = await repository.loadData(
+        q: event.search, page: event.nextPage ?? 1, onError: (e) => error = e);
+
+    if (event.nextPage != null) {
+      data?.data?.insertAll(0, state.data?.data ?? []);
+    }
+
+    emit(state.copyWith(isLoading: false, isPaginationLoading: false, data: data, error: error));
+  }
+}
diff --git a/lib/presentation/bloc/candy_bloc/candy_event.dart b/lib/presentation/bloc/candy_bloc/candy_event.dart
new file mode 100644
index 0000000..6ed4fd8
--- /dev/null
+++ b/lib/presentation/bloc/candy_bloc/candy_event.dart
@@ -0,0 +1,10 @@
+abstract class CandyEvent {
+  const CandyEvent();
+}
+
+class CandyLoadDataEvent extends CandyEvent {
+  final String? search;
+  final int? nextPage;
+
+  const CandyLoadDataEvent({this.search, this.nextPage});
+}
diff --git a/lib/presentation/bloc/candy_bloc/candy_state.dart b/lib/presentation/bloc/candy_bloc/candy_state.dart
new file mode 100644
index 0000000..8f9a89b
--- /dev/null
+++ b/lib/presentation/bloc/candy_bloc/candy_state.dart
@@ -0,0 +1,25 @@
+import 'package:candystore/models/candy_data.dart';
+import 'package:equatable/equatable.dart';
+
+class CandyState extends Equatable {
+  final CandyData? data;
+  final bool isLoading;
+  final bool isPaginationLoading;
+  final String? error;
+
+  const CandyState(
+      {this.data, this.isLoading = false, this.isPaginationLoading = false, this.error});
+
+  // Получение нового экземпляра состояния
+  CandyState copyWith(
+          {CandyData? data, bool? isLoading, bool? isPaginationLoading, String? error}) =>
+      CandyState(
+          data: data ?? this.data,
+          isLoading: isLoading ?? this.isLoading,
+          isPaginationLoading: isPaginationLoading ?? this.isPaginationLoading,
+          error: error ?? this.error);
+
+  // Поля, по которым Equtable сравнивает состояния
+  @override
+  List<Object?> get props => [data, isLoading, isPaginationLoading, error];
+}
diff --git a/lib/presentation/pages/home_page/candy_page.dart b/lib/presentation/pages/home_page/candy_page.dart
index 85ad7e7..ddb92d4 100644
--- a/lib/presentation/pages/home_page/candy_page.dart
+++ b/lib/presentation/pages/home_page/candy_page.dart
@@ -1,5 +1,4 @@
 import 'dart:math';
-import 'package:candystore/components/l10n/app_locale.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';