// update_provider.dart — 应用更新检查(启动自动检查 + 定时轮询)。
//
// 对照 jiu client/lib/providers/update_provider.dart:用 AsyncNotifier 的惰性
// build() 做「启动后延迟首查 + 每小时轮询」;shell 里 watch 一次即拉起整条流程。
// `_dismissed` 是本次进程内存标志(用户点「稍后」置真,防反复弹),每轮轮询重置。
// 强制更新(force_update)不受 dismiss 影响,由 UI 走不可关闭弹窗。
//
// 拿到更新后,下载安装走 core/update/app_updater.dart(App 内下载,不再开浏览器)。
import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:http/http.dart' as http;
import 'package:package_info_plus/package_info_plus.dart';

import '../services/api_config.dart';

/// 启动后首次检查的延迟(避开登录/首屏竞争)。
const _kInitialDelay = Duration(seconds: 3);

/// 轮询间隔。
const _kPollInterval = Duration(hours: 1);

/// 单次检查网络超时。
const _kCheckTimeout = Duration(seconds: 8);

/// 一次更新检查的结果。
class AppUpdateInfo {
  const AppUpdateInfo({
    required this.latestVersion,
    required this.buildNumber,
    required this.forceUpdate,
    required this.releaseNotes,
    required this.downloadUrls,
    required this.hasUpdate,
  });

  final String latestVersion;
  final int buildNumber;
  final bool forceUpdate;
  final String releaseNotes;
  final Map<String, String> downloadUrls;
  final bool hasUpdate;
}

/// 更新检查 Notifier。build() 惰性触发:延迟首查 + 每小时轮询。
class UpdateNotifier extends AsyncNotifier<AppUpdateInfo?> {
  Timer? _timer;
  Timer? _initialTimer;

  @override
  Future<AppUpdateInfo?> build() async {
    // 两个 timer 都在 onDispose 取消。初始延迟用可取消的 Timer(而非
    // Future.delayed:其内部 timer 无法取消,provider 在延迟期间被 dispose
    // 时会悬挂 → widget 测试报 pending timer、生产留资源)。
    ref.onDispose(() {
      _initialTimer?.cancel();
      _timer?.cancel();
    });
    final ready = Completer<void>();
    _initialTimer = Timer(_kInitialDelay, ready.complete);
    await ready.future; // 若延迟期间被 dispose,_initialTimer 取消 → 永不 complete,build 中止
    final first = await _check();
    _timer = Timer.periodic(_kPollInterval, (_) async {
      state = AsyncValue.data(await _check());
    });
    return first;
  }

  /// 设置页「检查更新」手动触发:立即查一次并回结果。
  Future<AppUpdateInfo?> forceCheck() async {
    final info = await _check();
    state = AsyncValue.data(info);
    return info;
  }

  /// 拉取 `$kApiBaseUrl/version` 并与本地版本比较。网络/解析失败返回 null(静默)。
  Future<AppUpdateInfo?> _check() async {
    try {
      final resp = await http
          .get(Uri.parse('$kApiBaseUrl/version'))
          .timeout(_kCheckTimeout);
      if (resp.statusCode != 200) return null;
      final data = jsonDecode(resp.body) as Map<String, dynamic>;

      final latestVersion = data['version'] as String? ?? '0.0.0';
      final buildNumber = (data['build_number'] as num?)?.toInt() ?? 0;
      final forceUpdate = data['force_update'] as bool? ?? false;
      final releaseNotes = data['release_notes'] as String? ?? '';
      final rawUrls = data['download_urls'] as Map<String, dynamic>? ?? const {};
      final downloadUrls = rawUrls.map((k, v) => MapEntry(k, v?.toString() ?? ''));

      final pkg = await PackageInfo.fromPlatform();
      final hasUpdate = _isNewer(latestVersion, pkg.version);

      return AppUpdateInfo(
        latestVersion: latestVersion,
        buildNumber: buildNumber,
        forceUpdate: forceUpdate,
        releaseNotes: releaseNotes,
        downloadUrls: downloadUrls,
        hasUpdate: hasUpdate,
      );
    } catch (_) {
      return null;
    }
  }

  /// 语义化版本比较:latest > current → true。容忍 1.1.4-dev / 1.1.4+7 等后缀。
  bool _isNewer(String latest, String current) {
    final l = _parse(latest);
    final c = _parse(current);
    for (var i = 0; i < 3; i++) {
      if (l[i] > c[i]) return true;
      if (l[i] < c[i]) return false;
    }
    return false;
  }

  List<int> _parse(String v) {
    final parts = v.split('.').map((s) {
      final m = RegExp(r'^\d+').firstMatch(s);
      return m == null ? 0 : int.parse(m.group(0)!);
    }).toList();
    while (parts.length < 3) {
      parts.add(0);
    }
    return parts;
  }
}

final updateProvider =
    AsyncNotifierProvider<UpdateNotifier, AppUpdateInfo?>(UpdateNotifier.new);

/// 用户在更新 banner 点「稍后再说」时忽略的版本号。忽略后 banner 隐藏;出现号
/// 不同的更新版本会重新显示;设置页手动「检查更新」会清空以重新提示。响应式,
/// 供 shell 顶部 banner 的显隐判断。
final dismissedUpdateVersionProvider = StateProvider<String?>((ref) => null);

/// 按当前平台从服务端 download_urls 里取对应下载直链。
String? platformDownloadUrl(Map<String, String> downloadUrls) {
  if (Platform.isMacOS) return downloadUrls['macos'];
  if (Platform.isWindows) return downloadUrls['windows'];
  if (Platform.isIOS) return downloadUrls['ios'];
  if (Platform.isAndroid) return downloadUrls['android'];
  return downloadUrls['web'];
}