merge new features

lib/services/announcement_service.dart

@@ -0,0 +1,108 @@
+import 'dart:convert';
+
+import 'package:crypto/crypto.dart';
+
+import 'api_service.dart';
+import 'storage_service.dart';
+import '../core/constants/storage_keys.dart';
+
+class SiteAnnouncement {
+  final String title;
+  final String html;
+  final String baseUrl;
+  final String fingerprint;
+
+  const SiteAnnouncement({
+    required this.title,
+    required this.html,
+    required this.baseUrl,
+    required this.fingerprint,
+  });
+}
+
+/// 登录后公告服务。
+///
+/// Cloudreve V4 SiteConfig 的公告字段是 site_notice。
+/// 不读取 custom_html.headless_bottom / sidebar_bottom，那些是页面装饰 HTML。
+///
+/// 弹窗策略：
+/// - 公告为空：不弹；
+/// - 当前公告内容和用户上次关闭时一致：不弹；
+/// - 公告内容变化：重新弹。
+class AnnouncementService {
+  AnnouncementService._();
+
+  static final AnnouncementService instance = AnnouncementService._();
+
+  bool _shownInSession = false;
+
+  /// 兼容旧调用。新的判断以持久化 fingerprint 为准。
+  bool get hasShown => _shownInSession;
+
+  /// 兼容旧调用。新的业务请使用 [markDismissed]。
+  void markShown() {
+    _shownInSession = true;
+  }
+
+  Future<SiteAnnouncement?> getSiteNotice() async {
+    final response = await ApiService.instance.get<Map<String, dynamic>>(
+      '/site/config/basic',
+    );
+
+    final data = _asMap(response['data']) ?? response;
+    final notice = data['site_notice']?.toString().trim();
+
+    if (notice == null || notice.isEmpty) {
+      return null;
+    }
+
+    final baseUrl = ApiService.instance.dio.options.baseUrl;
+    return SiteAnnouncement(
+      title: '公告',
+      html: notice,
+      baseUrl: baseUrl,
+      fingerprint: _fingerprint(baseUrl: baseUrl, html: notice),
+    );
+  }
+
+  /// 只返回需要弹出的公告。
+  ///
+  /// 用户关闭过同一条公告后，后续启动不会重复弹；站点公告内容改变后会再次弹。
+  Future<SiteAnnouncement?> getChangedSiteNotice() async {
+    final notice = await getSiteNotice();
+    if (notice == null) return null;
+
+    if (_shownInSession) return null;
+
+    final dismissedFingerprint = await StorageService.instance.getString(
+      StorageKeys.siteAnnouncementDismissedFingerprint,
+    );
+
+    if (dismissedFingerprint == notice.fingerprint) {
+      _shownInSession = true;
+      return null;
+    }
+
+    return notice;
+  }
+
+  /// 用户关闭公告后调用。
+  Future<void> markDismissed(SiteAnnouncement announcement) async {
+    _shownInSession = true;
+    await StorageService.instance.setString(
+      StorageKeys.siteAnnouncementDismissedFingerprint,
+      announcement.fingerprint,
+    );
+  }
+
+  String _fingerprint({required String baseUrl, required String html}) {
+    final normalized = '${baseUrl.trim()}\n${html.trim()}';
+    return sha256.convert(utf8.encode(normalized)).toString();
+  }
+
+  Map<String, dynamic>? _asMap(dynamic value) {
+    if (value is Map<String, dynamic>) return value;
+    if (value is Map) return Map<String, dynamic>.from(value);
+    return null;
+  }
+}