xianyan/lib/features/template/wallpaper_provider.dart

/// ============================================================
/// 闲言APP — 壁纸模板状态管理
/// 创建时间: 2026-05-01
/// 更新时间: 2026-05-01
/// 作用: 壁纸图库状态 — 来源/分类/分页/搜索
/// 上次更新: 初始创建
/// ============================================================

import 'dart:async';

import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../../core/utils/logger.dart';
import 'models/template_models.dart';
import 'services/wallpaper_service.dart';

// ============================================================
// State
// ============================================================

class WallpaperState {
  const WallpaperState({
    this.items = const [],
    this.currentSource = WallpaperSource.unsplash,
    this.currentCategory = WallpaperCategory.all,
    this.currentPage = 1,
    this.totalPages = 1,
    this.hasNext = false,
    this.isLoading = true,
    this.searchQuery,
  });

  final List<WallpaperItem> items;
  final WallpaperSource currentSource;
  final WallpaperCategory currentCategory;
  final int currentPage;
  final int totalPages;
  final bool hasNext;
  final bool isLoading;
  final String? searchQuery;

  WallpaperState copyWith({
    List<WallpaperItem>? items,
    WallpaperSource? currentSource,
    WallpaperCategory? currentCategory,
    int? currentPage,
    int? totalPages,
    bool? hasNext,
    bool? isLoading,
    String? searchQuery,
    bool clearSearch = false,
  }) => WallpaperState(
    items: items ?? this.items,
    currentSource: currentSource ?? this.currentSource,
    currentCategory: currentCategory ?? this.currentCategory,
    currentPage: currentPage ?? this.currentPage,
    totalPages: totalPages ?? this.totalPages,
    hasNext: hasNext ?? this.hasNext,
    isLoading: isLoading ?? this.isLoading,
    searchQuery: clearSearch ? null : (searchQuery ?? this.searchQuery),
  );
}

// ============================================================
// Notifier
// ============================================================

class WallpaperNotifier extends Notifier<WallpaperState> {
  Timer? _debounce;

  @override
  WallpaperState build() {
    ref.onDispose(() { _debounce?.cancel(); });
    Future.microtask(() {
      loadWallpapers().catchError((Object e) { Log.e('WallpaperNotifier.loadWallpapers 失败', e); });
    }).catchError((_) {});
    return const WallpaperState();
  }

  WallpaperNotifier();

  Future<void> loadWallpapers({bool refresh = false}) async {
    if (refresh) {
      state = state.copyWith(currentPage: 1, clearSearch: true);
    }
    state = state.copyWith(isLoading: true);

    try {
      final result = await WallpaperService.fetchWallpapers(
        source: state.currentSource,
        page: refresh ? 1 : state.currentPage,
        category: state.currentCategory,
        search: state.searchQuery,
      );

      final newItems = refresh
          ? result.items
          : [...state.items, ...result.items];

      state = state.copyWith(
        items: newItems,
        currentPage: result.currentPage,
        totalPages: result.totalPages,
        hasNext: result.hasNext,
        isLoading: false,
      );
      Log.i('壁纸加载成功: ${result.items.length} 张 (共${result.totalPages}页)');
    } catch (e) {
      Log.e('壁纸加载失败', e);
      state = state.copyWith(isLoading: false);
    }
  }

  Future<void> loadMore() async {
    if (state.isLoading || !state.hasNext) return;
    final nextPage = state.currentPage + 1;
    state = state.copyWith(isLoading: true);
    try {
      final result = await WallpaperService.fetchWallpapers(
        source: state.currentSource,
        page: nextPage,
        category: state.currentCategory,
        search: state.searchQuery,
      );
      state = state.copyWith(
        items: [...state.items, ...result.items],
        currentPage: result.currentPage,
        totalPages: result.totalPages,
        hasNext: result.hasNext,
        isLoading: false,
      );
    } catch (e) {
      Log.e('加载更多壁纸失败', e);
      state = state.copyWith(isLoading: false);
    }
  }

  void setSource(WallpaperSource source) {
    if (source == state.currentSource) return;
    state = state.copyWith(currentSource: source, items: []);
    loadWallpapers(refresh: true);
  }

  void setCategory(WallpaperCategory category) {
    if (category == state.currentCategory) return;
    state = state.copyWith(currentCategory: category, items: []);
    loadWallpapers(refresh: true);
  }

  void search(String query) {
    if (query == state.searchQuery) return;
    _debounce?.cancel();
    state = state.copyWith(searchQuery: query);
    _debounce = Timer(const Duration(milliseconds: 300), () {
      loadWallpapers(refresh: true);
    });
  }

  void clearSearch() {
    if (state.searchQuery == null) return;
    _debounce?.cancel();
    state = state.copyWith(clearSearch: true);
    loadWallpapers(refresh: true);
  }
}

// ============================================================
// Provider
// ============================================================

final wallpaperProvider = NotifierProvider<WallpaperNotifier, WallpaperState>(
  WallpaperNotifier.new,
);