Files
plezy/lib/providers/explore_provider.dart
T

388 lines
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Dart

import 'dart:async';
import 'package:flutter/foundation.dart';
import '../i18n/strings.g.dart';
import '../media/media_hub.dart';
import '../media/media_item.dart';
import '../mixins/disposable_change_notifier_mixin.dart';
import '../services/catalog/catalog_source.dart';
import '../services/trackers/future_coalescer.dart';
import '../utils/app_logger.dart';
import 'catalog_sources_provider.dart';
enum ExploreLoadState { initial, loading, loaded, error }
/// One rendered Explore shelf, backed by either a fixed catalog row or a
/// provider-defined hub.
class ExploreRowHub {
final CatalogRowId? row;
final String? providerHubId;
final MediaHub hub;
const ExploreRowHub.catalogRow({required CatalogRowId this.row, required this.hub}) : providerHubId = null;
const ExploreRowHub.providerHub({required String this.providerHubId, required this.hub}) : row = null;
}
/// Owns the Explore tab's fixed rows and provider-defined hubs, converted to
/// [MediaHub]s so the existing shelf stack renders them.
///
/// Lives inside the profile-keyed provider subtree. Listens to
/// [CatalogSourcesProvider] for the active source (connect/disconnect/switch)
/// and to the source's watchlist changes so the Watchlist row stays current
/// after mutations from anywhere in the app.
class ExploreProvider extends ChangeNotifier with DisposableChangeNotifierMixin {
/// Rows reload when the tab is shown after this long.
static const Duration staleAfter = Duration(minutes: 15);
static const int rowLimit = 25;
static const int viewAllPageLimit = 100;
static const int viewAllMaxPages = 3;
/// Watchlist mutations notify optimistically before the API call finishes;
/// the row refetch waits out the burst so it reads settled server state.
static const Duration _watchlistRefreshDelay = Duration(seconds: 1);
ExploreProvider(this._catalogSources) {
_catalogSources.addListener(_onSourcesChanged);
_source = _catalogSources.activeSource;
_source?.watchlistChanges.addListener(_onWatchlistChanged);
}
final CatalogSourcesProvider _catalogSources;
CatalogSource? _source;
Map<CatalogRowId, CatalogPage> _rows = {};
List<CatalogHub> _providerHubs = const [];
ExploreLoadState _state = ExploreLoadState.initial;
String? _errorMessage;
DateTime? _loadedAt;
final FutureCoalescer<void> _loadCoalescer = FutureCoalescer();
int _generation = 0;
Timer? _watchlistRefreshTimer;
// Watchlist-row freshness: every membership change bumps the mutation
// epoch; a successful row refetch records which epoch it covered. A tab
// re-shown with uncovered mutations refetches immediately — the debounced
// timer alone can lose the race when the user navigates back quickly.
int _watchlistMutationEpoch = 0;
int _watchlistRowFetchedEpoch = 0;
int _watchlistHubRetryEpoch = -1;
final FutureCoalescer<void> _watchlistRefreshCoalescer = FutureCoalescer();
List<ExploreRowHub>? _hubsCache;
(int, String)? _hubsCacheKey;
int _rowsEpoch = 0;
CatalogSource? get activeSource => _source;
ExploreLoadState get state => _state;
bool get isLoading => _state == ExploreLoadState.initial || _state == ExploreLoadState.loading;
/// Raw load failure (unlocalized); the screen wraps it for display.
String? get errorMessage => _errorMessage;
/// Non-empty rows of the active source in display order. Memoized on row
/// content (and one localized string, so a locale change busts the cache).
List<ExploreRowHub> get rowHubs {
final source = _source;
if (source == null) return const [];
final key = (_rowsEpoch, rowTitle(CatalogRowId.watchlist));
if (_hubsCache != null && key == _hubsCacheKey) return _hubsCache!;
final hubs = <ExploreRowHub>[
for (final row in source.supportedRows)
if (_rows[row] case final CatalogPage page)
if (page.items.isNotEmpty)
ExploreRowHub.catalogRow(
row: row,
hub: MediaHub(
id: 'explore:${source.id.name}:${row.name}',
identifier: 'explore.${row.name}',
title: rowTitle(row),
type: 'mixed',
items: [for (final item in page.items) item.toMediaItem()],
size: page.items.length,
more: page.hasMore,
),
),
for (final providerHub in _providerHubs)
if (providerHub.page.items.isNotEmpty)
ExploreRowHub.providerHub(
providerHubId: providerHub.id,
hub: MediaHub(
id: 'explore:${source.id.name}:hub:${providerHub.id}',
identifier: 'explore.hub.${providerHub.id}',
title: providerHub.title,
type: 'mixed',
items: [for (final item in providerHub.page.items) item.toMediaItem()],
size: providerHub.page.items.length,
more: providerHub.page.hasMore,
),
),
];
_hubsCache = hubs;
_hubsCacheKey = key;
return hubs;
}
static String rowTitle(CatalogRowId row) => switch (row) {
CatalogRowId.watchlist => t.explore.rows.watchlist,
CatalogRowId.recommendedMovies => t.explore.rows.recommendedMovies,
CatalogRowId.recommendedShows => t.explore.rows.recommendedShows,
CatalogRowId.trendingMovies => t.explore.rows.trendingMovies,
CatalogRowId.trendingShows => t.explore.rows.trendingShows,
CatalogRowId.popularMovies => t.explore.rows.popularMovies,
CatalogRowId.popularShows => t.explore.rows.popularShows,
CatalogRowId.trendingAnime => t.explore.rows.trendingAnime,
CatalogRowId.suggestedAnime => t.explore.rows.suggestedAnime,
CatalogRowId.airingAnime => t.explore.rows.airingAnime,
CatalogRowId.popularAnime => t.explore.rows.popularAnime,
CatalogRowId.trending => t.explore.rows.trending,
CatalogRowId.upcomingMovies => t.explore.rows.upcomingMovies,
CatalogRowId.upcomingShows => t.explore.rows.upcomingShows,
};
/// Load if never loaded, after an error, or when the content has gone
/// stale. Called on first build and every time the tab is shown.
void ensureFresh() {
if (_source == null) return;
if (_state == ExploreLoadState.initial || _state == ExploreLoadState.error) {
unawaited(load());
return;
}
final loadedAt = _loadedAt;
if (loadedAt != null && DateTime.now().difference(loadedAt) > staleAfter) {
unawaited(load());
return;
}
if (_watchlistRowFetchedEpoch < _watchlistMutationEpoch) {
unawaited(_refreshWatchlistRow());
}
}
/// Full reload of every supported row (one request per row). Concurrent
/// calls coalesce into the in-flight pass; a source switch resets the
/// coalescer (see [_onSourcesChanged]) so the new source's load starts
/// instead of joining the doomed one.
Future<void> load() => _loadCoalescer.run(_loadOnce);
Future<void> _loadOnce() async {
// Yield so a load() kicked off during build can't notify mid-build.
await null;
if (isDisposed) return;
final source = _source;
if (source == null) return;
final generation = _generation;
final mutationEpochAtStart = _watchlistMutationEpoch;
_state = ExploreLoadState.loading;
_errorMessage = null;
safeNotifyListeners();
final fetched = <CatalogRowId, CatalogPage>{};
List<CatalogHub>? fetchedProviderHubs;
Object? firstError;
final CatalogHubSource? hubSource = source is CatalogHubSource ? source as CatalogHubSource : null;
await Future.wait<void>([
for (final row in source.supportedRows)
() async {
try {
fetched[row] = await source.fetchRow(row, limit: rowLimit);
} catch (e) {
appLogger.w('Explore: ${source.id.name} row ${row.name} failed', error: e);
firstError ??= e;
}
}(),
if (hubSource != null)
() async {
try {
fetchedProviderHubs = await hubSource.fetchHubs(limit: rowLimit);
} catch (e) {
appLogger.w('Explore: ${source.id.name} provider hubs failed', error: e);
firstError ??= e;
}
}(),
]);
if (isDisposed || generation != _generation) return;
// A debounced watchlist refresh that landed while this load was in
// flight covered later mutations than both the watchlist page and Plex's
// watchlist-derived hubs — keep the fresher versions.
if (_watchlistRowFetchedEpoch > mutationEpochAtStart) {
fetched.remove(CatalogRowId.watchlist);
fetchedProviderHubs = null;
}
if (fetched.isEmpty && (fetchedProviderHubs == null || (fetchedProviderHubs!.isEmpty && firstError != null))) {
// Nothing succeeded: keep stale rows if any (they beat an error flash),
// otherwise surface the failure. A null message falls back to the
// localized empty-state text in the screen.
if (_rows.isEmpty && _providerHubs.isEmpty) {
_state = ExploreLoadState.error;
_errorMessage = firstError?.toString();
} else {
_state = ExploreLoadState.loaded;
}
} else {
// Failed rows and hubs keep their previous content.
_rows = {..._rows, ...fetched};
if (fetchedProviderHubs case final hubs?) _providerHubs = hubs;
_state = ExploreLoadState.loaded;
_loadedAt = DateTime.now();
_rowsEpoch++;
if (fetched.containsKey(CatalogRowId.watchlist) && mutationEpochAtStart > _watchlistRowFetchedEpoch) {
_watchlistRowFetchedEpoch = mutationEpochAtStart;
}
}
// Mutations that landed while the load was in flight aren't reflected in
// the page we just stored — schedule the debounced catch-up ourselves
// (the mutation-time notification skips rows that aren't loaded yet).
if (_rows.containsKey(CatalogRowId.watchlist) && _watchlistRowFetchedEpoch < _watchlistMutationEpoch) {
_scheduleWatchlistRefresh();
}
safeNotifyListeners();
}
/// Full item list for a fixed row's View All grid.
Future<List<MediaItem>> loadAllForRow(CatalogRowId row) async {
final source = _source;
if (source == null) return const [];
return _loadAllPages(row.name, (page) => source.fetchRow(row, page: page, limit: viewAllPageLimit));
}
/// Full item list for either a fixed row or a provider-defined hub.
Future<List<MediaItem>> loadAllForHub(ExploreRowHub rowHub) async {
if (rowHub.row case final row?) return loadAllForRow(row);
final source = _source;
final hubId = rowHub.providerHubId;
if (source is! CatalogHubSource || hubId == null) return rowHub.hub.items;
final hubSource = source as CatalogHubSource;
return _loadAllPages(hubId, (page) => hubSource.fetchHub(hubId, page: page, limit: viewAllPageLimit));
}
Future<List<MediaItem>> _loadAllPages(String label, Future<CatalogPage> Function(int page) fetchPage) async {
final items = <MediaItem>[];
var page = 1;
while (true) {
final result = await fetchPage(page);
items.addAll([for (final item in result.items) item.toMediaItem()]);
if (!result.hasMore) break;
if (page >= viewAllMaxPages) {
appLogger.w('Explore: $label View All truncated at ${items.length} items ($page pages)');
break;
}
page++;
}
return items;
}
void _onSourcesChanged() {
final next = _catalogSources.activeSource;
if (identical(next, _source)) return;
_source?.watchlistChanges.removeListener(_onWatchlistChanged);
_source = next;
_source?.watchlistChanges.addListener(_onWatchlistChanged);
_generation++;
_watchlistRefreshTimer?.cancel();
// Detach any in-flight passes for the old source: their generation guard
// already discards their results, but the new source's load must not
// coalesce into them (that left the tab stuck on the loading state).
_loadCoalescer.reset();
_watchlistRefreshCoalescer.reset();
_watchlistMutationEpoch = 0;
_watchlistRowFetchedEpoch = 0;
_watchlistHubRetryEpoch = -1;
_rows = {};
_providerHubs = const [];
_loadedAt = null;
_errorMessage = null;
_state = ExploreLoadState.initial;
_rowsEpoch++;
safeNotifyListeners();
if (next != null) unawaited(load());
}
void _onWatchlistChanged() {
// Always bump: a mutation during the initial full load has no row to
// patch yet, but the load's completion checks this epoch to catch up.
_watchlistMutationEpoch++;
if (!_rows.containsKey(CatalogRowId.watchlist)) return;
_scheduleWatchlistRefresh();
}
void _scheduleWatchlistRefresh() {
_watchlistRefreshTimer?.cancel();
_watchlistRefreshTimer = Timer(_watchlistRefreshDelay, () => unawaited(_refreshWatchlistRow()));
}
Future<void> _refreshWatchlistRow() => _watchlistRefreshCoalescer.run(_refreshWatchlistRowOnce);
Future<void> _refreshWatchlistRowOnce() async {
final source = _source;
if (source == null || isDisposed) return;
final generation = _generation;
final coveredEpoch = _watchlistMutationEpoch;
CatalogPage? fetchedPage;
List<CatalogHub>? fetchedProviderHubs;
final CatalogHubSource? hubSource = source is CatalogHubSource ? source as CatalogHubSource : null;
var providerHubRefreshFailed = false;
await Future.wait<void>([
() async {
try {
fetchedPage = await source.fetchRow(CatalogRowId.watchlist, limit: rowLimit);
} catch (e) {
appLogger.w('Explore: watchlist row refresh failed', error: e);
}
}(),
if (hubSource != null)
() async {
try {
fetchedProviderHubs = await hubSource.fetchHubs(limit: rowLimit);
} catch (e) {
appLogger.w('Explore: ${source.id.name} provider hub refresh failed', error: e);
}
}(),
]);
providerHubRefreshFailed = hubSource != null && fetchedProviderHubs == null;
if (isDisposed || generation != _generation) return;
if (fetchedPage == null && fetchedProviderHubs == null) return;
if (fetchedPage case final page?) {
_rows = {..._rows, CatalogRowId.watchlist: page};
if (!providerHubRefreshFailed) {
_watchlistRowFetchedEpoch = coveredEpoch;
_watchlistHubRetryEpoch = -1;
}
}
if (fetchedProviderHubs case final hubs?) _providerHubs = hubs;
_rowsEpoch++;
safeNotifyListeners();
if (fetchedPage == null) return;
if (providerHubRefreshFailed) {
// One automatic retry per mutation epoch avoids leaving derived hubs
// stale without hammering an unavailable endpoint indefinitely.
if (_watchlistHubRetryEpoch != coveredEpoch) {
_watchlistHubRetryEpoch = coveredEpoch;
_scheduleWatchlistRefresh();
}
} else if (_watchlistMutationEpoch > coveredEpoch) {
// Mutations that arrived during this pass need one more refresh.
_scheduleWatchlistRefresh();
} else {
// Fully caught up: a still-pending debounce would only refetch the same
// state.
_watchlistRefreshTimer?.cancel();
}
}
@override
void dispose() {
_catalogSources.removeListener(_onSourcesChanged);
_source?.watchlistChanges.removeListener(_onWatchlistChanged);
_watchlistRefreshTimer?.cancel();
super.dispose();
}
}