Solian/lib/controllers/post_list_controller.dart
2024-09-02 23:11:40 +08:00

172 lines
4.3 KiB
Dart

import 'dart:math';
import 'package:get/get.dart';
import 'package:infinite_scroll_pagination/infinite_scroll_pagination.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:solian/models/pagination.dart';
import 'package:solian/models/post.dart';
import 'package:solian/providers/content/posts.dart';
class PostListController extends GetxController {
late final SharedPreferences _prefs;
String? author;
/// The polling source modifier.
/// - `0`: default recommendations
/// - `1`: friend mode
/// - `2`: shuffle mode
RxInt mode = 0.obs;
/// The paging controller for infinite loading.
/// Only available when mode is `0` or `1`.
PagingController<int, Post> pagingController =
PagingController(firstPageKey: 0);
PostListController({this.author}) {
_initPreferences();
_initPagingController();
}
void _initPreferences() {
SharedPreferences.getInstance().then((prefs) {
_prefs = prefs;
});
}
/// Initialize a compatibility layer to paging controller
void _initPagingController() {
pagingController.addPageRequestListener(_onPagingControllerRequest);
}
Future<void> _onPagingControllerRequest(int pageKey) async {
try {
final result = await loadMore();
if (result != null && hasMore.value) {
pagingController.appendPage(result, nextPageKey.value);
} else if (result != null) {
pagingController.appendLastPage(result);
}
} catch (e) {
pagingController.error = e;
}
}
void _resetPagingController() {
pagingController.removePageRequestListener(_onPagingControllerRequest);
pagingController.nextPageKey = nextPageKey.value;
pagingController.itemList?.clear();
}
RxBool isBusy = false.obs;
RxBool isPreparing = false.obs;
RxInt focusCursor = 0.obs;
Post get focusPost => postList[focusCursor.value];
RxInt postTotal = 0.obs;
RxList<Post> postList = RxList.empty(growable: true);
RxInt nextPageKey = 0.obs;
RxBool hasMore = true.obs;
Future<void> reloadAllOver() async {
isPreparing.value = true;
focusCursor.value = 0;
nextPageKey.value = 0;
postList.clear();
hasMore.value = true;
_resetPagingController();
final result = await loadMore();
if (result != null && hasMore.value) {
pagingController.appendPage(result, nextPageKey.value);
} else if (result != null) {
pagingController.appendLastPage(result);
}
_initPagingController();
isPreparing.value = false;
}
Future<List<Post>?> loadMore() async {
final result = await _loadPosts(nextPageKey.value);
if (result != null && result.length >= 10) {
postList.addAll(result);
nextPageKey.value += result.length;
hasMore.value = true;
} else if (result != null) {
postList.addAll(result);
nextPageKey.value += result.length;
hasMore.value = false;
}
final idx = <dynamic>{};
postList.retainWhere((x) => idx.add(x.id));
var lastId = postList.map((x) => x.id).reduce(max);
if (_prefs.containsKey('feed_last_read_at')) {
final storedId = _prefs.getInt('feed_last_read_at') ?? 0;
lastId = max(storedId, lastId);
}
_prefs.setInt('feed_last_read_at', lastId);
return result;
}
Future<List<Post>?> _loadPosts(int pageKey) async {
isBusy.value = true;
final PostProvider provider = Get.find();
Response resp;
try {
if (author != null) {
resp = await provider.listPost(
pageKey,
author: author,
);
} else {
switch (mode.value) {
case 2:
resp = await provider.listRecommendations(
pageKey,
channel: 'shuffle',
);
break;
case 1:
resp = await provider.listRecommendations(
pageKey,
channel: 'friends',
);
break;
default:
resp = await provider.listRecommendations(pageKey);
break;
}
}
} catch (e) {
rethrow;
} finally {
isBusy.value = false;
}
final result = PaginationResult.fromJson(resp.body);
final out = result.data?.map((e) => Post.fromJson(e)).toList();
postTotal.value = result.count;
return out;
}
@override
void dispose() {
pagingController.dispose();
super.dispose();
}
}