feat: infinite query implementation

packages/fl_query/lib/src/collections/default_configs.dart

@@ -1,5 +1,5 @@
-import 'package:fl_query/src/core/query.dart';
-import 'package:fl_query/src/core/retryer.dart';
+import 'package:fl_query/src/collections/refresh_config.dart';
+import 'package:fl_query/src/collections/retry_config.dart';
 
 abstract class DefaultConstants {
   static const RetryConfig retryConfig = RetryConfig(
@@ -11,5 +11,6 @@ abstract class DefaultConstants {
   static const RefreshConfig refreshConfig = RefreshConfig(
     staleDuration: Duration(seconds: 10),
     refreshInterval: Duration(seconds: 5),
+    refreshOnMount: true,
   );
 }

packages/fl_query/lib/src/collections/json_config.dart

@@ -0,0 +1,9 @@
+class JsonConfig<T> {
+  final Map<String, dynamic> Function(T data) toJson;
+  final T Function(Map<String, dynamic> json) fromJson;
+
+  const JsonConfig({
+    required this.toJson,
+    required this.fromJson,
+  });
+}

packages/fl_query/lib/src/collections/refresh_config.dart

@@ -0,0 +1,11 @@
+class RefreshConfig {
+  final Duration staleDuration;
+  final Duration refreshInterval;
+  final bool refreshOnMount;
+
+  const RefreshConfig({
+    required this.staleDuration,
+    required this.refreshInterval,
+    required this.refreshOnMount,
+  });
+}

packages/fl_query/lib/src/collections/retry_config.dart

@@ -0,0 +1,11 @@
+class RetryConfig {
+  final int maxRetries;
+  final Duration retryDelay;
+  final Duration timeout;
+
+  const RetryConfig({
+    required this.maxRetries,
+    required this.retryDelay,
+    required this.timeout,
+  });
+}

packages/fl_query/lib/src/core/infinite_query.dart

@@ -0,0 +1,247 @@
+import 'dart:async';
+
+import 'package:collection/collection.dart';
+import 'package:fl_query/src/collections/default_configs.dart';
+import 'package:fl_query/src/collections/json_config.dart';
+import 'package:fl_query/src/collections/refresh_config.dart';
+import 'package:fl_query/src/collections/retry_config.dart';
+import 'package:fl_query/src/core/retryer.dart';
+import 'package:flutter/material.dart';
+import 'package:hive_flutter/adapters.dart';
+import 'package:mutex/mutex.dart';
+import 'package:state_notifier/state_notifier.dart';
+
+typedef InfiniteQueryFn<T, P> = FutureOr<T?> Function(P page);
+typedef InfiniteQueryNextPage<T, P> = P? Function(
+  P lastPage,
+  List<T> pages,
+);
+
+class InfiniteQueryPage<T, E, P> {
+  final P page;
+  final T? data;
+  final E? error;
+
+  final DateTime updatedAt;
+  final Duration staleDuration;
+
+  const InfiniteQueryPage({
+    required this.page,
+    this.data,
+    this.error,
+    required this.updatedAt,
+    required this.staleDuration,
+  });
+
+  bool get isStale => DateTime.now().difference(updatedAt) > staleDuration;
+
+  InfiniteQueryPage<T, E, P> copyWith({
+    T? data,
+    E? error,
+  }) {
+    return InfiniteQueryPage<T, E, P>(
+      page: page,
+      updatedAt: DateTime.now(),
+      staleDuration: staleDuration,
+      data: data ?? this.data,
+      error: error ?? this.error,
+    );
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+
+    return other is InfiniteQueryPage<T, E, P> && other.page == page;
+  }
+
+  @override
+  int get hashCode => page.hashCode;
+}
+
+class InfiniteQueryState<T, E, P> {
+  final Set<InfiniteQueryPage<T, E, P>> pages;
+  final InfiniteQueryFn<T, P> queryFn;
+  final InfiniteQueryNextPage<T, P> nextPage;
+
+  const InfiniteQueryState({
+    required this.pages,
+    required this.queryFn,
+    required this.nextPage,
+  });
+
+  P get lastPage => pages.last.page;
+  P? get getNextPage => nextPage(lastPage, pages.map((e) => e.data!).toList());
+  bool get hasNextPage => getNextPage != null;
+
+  InfiniteQueryState<T, E, P> copyWith({
+    Set<InfiniteQueryPage<T, E, P>>? pages,
+    InfiniteQueryFn<T, P>? queryFn,
+    InfiniteQueryNextPage<T, P>? nextPage,
+  }) {
+    return InfiniteQueryState<T, E, P>(
+      pages: pages ?? this.pages,
+      queryFn: queryFn ?? this.queryFn,
+      nextPage: nextPage ?? this.nextPage,
+    );
+  }
+}
+
+class InfiniteQuery<T, E, K, P>
+    extends StateNotifier<InfiniteQueryState<T, E, P>> with Retryer<T, E> {
+  final ValueKey<K> key;
+  final RetryConfig retryConfig;
+  final RefreshConfig refreshConfig;
+  final JsonConfig<T>? jsonConfig;
+
+  InfiniteQuery(
+    this.key,
+    InfiniteQueryFn<T, P> queryFn, {
+    required InfiniteQueryNextPage<T, P> nextPage,
+    required P initialParam,
+    this.retryConfig = DefaultConstants.retryConfig,
+    this.refreshConfig = DefaultConstants.refreshConfig,
+    this.jsonConfig,
+  }) : super(InfiniteQueryState<T, E, P>(
+          pages: {
+            InfiniteQueryPage<T, E, P>(
+              page: initialParam,
+              updatedAt: DateTime.now(),
+              staleDuration: refreshConfig.staleDuration,
+            ),
+          },
+          queryFn: queryFn,
+          nextPage: nextPage,
+        )) {
+    if (jsonConfig != null) {
+      _mutex.protect(() async {
+        final json = await _box.get(key.value);
+        if (json != null) {
+          state = state.copyWith(
+            pages: json.map(
+              (key, value) => MapEntry(
+                key as P,
+                jsonConfig!.fromJson(value),
+              ),
+            ),
+          );
+        }
+      });
+
+      Timer.periodic(refreshConfig.refreshInterval, (_) async {
+        await Future.wait(
+          state.pages.map((page) async {
+            if (page.isStale) {
+              return await refresh(page.page);
+            }
+          }),
+        );
+      });
+    }
+  }
+
+  final _mutex = Mutex();
+  final _box = Hive.lazyBox("cache");
+
+  List<T> get pages => state.pages.map((e) => e.data).whereType<T>().toList();
+  List<E> get errors => state.pages.map((e) => e.error).whereType<E>().toList();
+  P get lastPage => state.lastPage;
+
+  bool get isLoadingPage => !hasPageData && !hasPageError && _mutex.isLocked;
+  bool get isRefreshingPage => (hasPageData || hasPageError) && _mutex.isLocked;
+
+  bool get hasPages => pages.isNotEmpty;
+  bool get hasErrors => errors.isNotEmpty;
+
+  bool get hasPageData => state.pages.last.data != null;
+  bool get hasPageError => state.pages.last.error != null;
+
+  bool get hasNextPage => state.hasNextPage;
+
+  Future<void> _operation(P page) {
+    return _mutex.protect(() async {
+      retryOperation(
+        () => state.queryFn(page),
+        config: retryConfig,
+        onSuccessful: (data) async {
+          state = state.copyWith(
+            pages: {
+              ...state.pages,
+              state.pages
+                  .firstWhere(
+                    (e) => e.page == page,
+                    orElse: () => InfiniteQueryPage<T, E, P>(
+                      page: page,
+                      updatedAt: DateTime.now(),
+                      staleDuration: refreshConfig.staleDuration,
+                    ),
+                  )
+                  .copyWith(data: data),
+            },
+          );
+          if (jsonConfig != null) {
+            await _box.put(
+              key.value,
+              state.pages.map(
+                (e) => MapEntry(
+                  e.page,
+                  e.data != null ? jsonConfig!.toJson(e.data!) : null,
+                ),
+              ),
+            );
+          }
+        },
+        onFailed: (error) {
+          state = state.copyWith(
+            pages: {
+              ...state.pages,
+              state.pages
+                  .firstWhere(
+                    (e) => e.page == page,
+                    orElse: () => InfiniteQueryPage<T, E, P>(
+                      page: page,
+                      updatedAt: DateTime.now(),
+                      staleDuration: refreshConfig.staleDuration,
+                    ),
+                  )
+                  .copyWith(error: error),
+            },
+          );
+        },
+      );
+    });
+  }
+
+  Future<T?> fetch() async {
+    final lastPage = state.lastPage;
+    if (_mutex.isLocked || hasPageData || hasPageError)
+      return state.pages.last.data;
+    return await _operation(lastPage).then((_) => state.pages.last.data);
+  }
+
+  Future<T?> refresh([P? page]) async {
+    page ??= lastPage;
+    if (_mutex.isLocked)
+      return state.pages.firstWhereOrNull((e) => e.page == page)?.data;
+    return await _operation(page!).then((_) {
+      return state.pages.firstWhereOrNull((e) => e.page == page)?.data;
+    });
+  }
+
+  Future<List<T>?> refreshAll() async {
+    if (_mutex.isLocked) return pages;
+    return await Future.wait(
+      state.pages.map((e) => _operation(e.page)),
+    ).then((_) => pages);
+  }
+
+  Future<T?> fetchNext() async {
+    final nextPage = state.getNextPage;
+    if (_mutex.isLocked || nextPage != null) {
+      return state.pages.firstWhereOrNull((e) => e.page == nextPage)?.data;
+    }
+    return await _operation(nextPage!).then((_) {
+      return state.pages.firstWhereOrNull((e) => e.page == nextPage)?.data;
+    });
+  }
+}

packages/fl_query/lib/src/core/query.dart

@@ -1,6 +1,9 @@
 import 'dart:async';
 
 import 'package:fl_query/src/collections/default_configs.dart';
+import 'package:fl_query/src/collections/json_config.dart';
+import 'package:fl_query/src/collections/refresh_config.dart';
+import 'package:fl_query/src/collections/retry_config.dart';
 import 'package:fl_query/src/core/retryer.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:hive_flutter/adapters.dart';
@@ -12,7 +15,7 @@ typedef QueryFn<T> = FutureOr<T?> Function();
 class QueryState<T, E> {
   final T? data;
   final E? error;
-  final QueryFn<T>? queryFn;
+  final QueryFn<T> queryFn;
 
   final DateTime updatedAt;
   final Duration staleDuration;
@@ -20,7 +23,7 @@ class QueryState<T, E> {
   const QueryState({
     this.data,
     this.error,
-    this.queryFn,
+    required this.queryFn,
     required this.updatedAt,
     required this.staleDuration,
   });
@@ -44,26 +47,6 @@ class QueryState<T, E> {
   }
 }
 
-class JsonConfig<T> {
-  final Map<String, dynamic> Function(T data) toJson;
-  final T Function(Map<String, dynamic> json) fromJson;
-
-  const JsonConfig({
-    required this.toJson,
-    required this.fromJson,
-  });
-}
-
-class RefreshConfig {
-  final Duration staleDuration;
-  final Duration refreshInterval;
-
-  const RefreshConfig({
-    required this.staleDuration,
-    required this.refreshInterval,
-  });
-}
-
 class Query<T, E, K> extends StateNotifier<QueryState<T, E>>
     with Retryer<T, E> {
   final ValueKey<K> key;
@@ -112,10 +95,13 @@ class Query<T, E, K> extends StateNotifier<QueryState<T, E>>
   bool get hasData => state.data != null;
   bool get hasError => state.error != null;
 
+  T? get data => state.data;
+  E? get error => state.error;
+
   Future<void> _operate() {
     return _mutex.protect(() async {
       retryOperation(
-        state.queryFn!,
+        state.queryFn,
         config: retryConfig,
         onSuccessful: (T? data) {
           state = state.copyWith(data: data);
@@ -134,7 +120,7 @@ class Query<T, E, K> extends StateNotifier<QueryState<T, E>>
   }
 
   Future<T?> fetch() async {
-    if (_mutex.isLocked || hasData) return state.data;
+    if (_mutex.isLocked || hasData || hasError) return state.data;
     return _operate().then((_) => state.data);
   }
 
@@ -142,4 +128,12 @@ class Query<T, E, K> extends StateNotifier<QueryState<T, E>>
     if (_mutex.isLocked) return state.data;
     return _operate().then((_) => state.data);
   }
+
+  void updateQueryFn(QueryFn<T> queryFn) {
+    state = state.copyWith(queryFn: queryFn);
+  }
+
+  void setData(T data) {
+    state = state.copyWith(data: data);
+  }
 }

packages/fl_query/lib/src/core/retryer.dart

@@ -1,19 +1,8 @@
 import 'dart:async';
 
+import 'package:fl_query/src/collections/retry_config.dart';
 import 'package:flutter/foundation.dart';
 
-class RetryConfig {
-  final int maxRetries;
-  final Duration retryDelay;
-  final Duration timeout;
-
-  const RetryConfig({
-    required this.maxRetries,
-    required this.retryDelay,
-    required this.timeout,
-  });
-}
-
 mixin Retryer<T, E> {
   VoidCallback retryOperation(
     FutureOr<T?> Function() operation, {