// app_updater.dart — App 内下载并安装更新(不再开浏览器)。
//
// 对照 jiu core/update/app_updater_io.dart,但补上了 jiu 没有的 Android 原生安装:
//   - Android:http 流式下 APK 到临时目录 → open_filex 拉起系统安装器
//              (open_filex 内部封装 FileProvider;manifest 需 REQUEST_INSTALL_PACKAGES)
//   - Windows:下 exe → Process.start(detached) 起安装 → exit(0) 让其覆盖
//   - macOS :下 zip → open 解压 + 访达显示,提示手动拖入「应用程序」
//            (本 app 带系统扩展,不自动替换 bundle,避免破坏 sysext)
//   - iOS   :不能 App 内装 → 外链(TestFlight/App Store)
// 进度用本地 ValueNotifier 驱动一个不可关闭的进度对话框;失败降级浏览器下载。
import 'dart:async';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:open_filex/open_filex.dart';
import 'package:path_provider/path_provider.dart';
import 'package:url_launcher/url_launcher.dart';

import '../../l10n/app_text.dart';
import '../../pangolin_theme.dart';
import '../../state/update_provider.dart';
import '../../widgets/pangolin_icons.dart';

/// 更新对话框「下载更新」入口:按平台 App 内下载并安装;iOS/无直链降级浏览器。
Future<void> startInAppUpdate(BuildContext context, AppText t, AppUpdateInfo info) async {
  final url = platformDownloadUrl(info.downloadUrls);
  if (url == null || url.isEmpty) return;

  // iOS 不允许 App 内安装 → 外链(download_urls['ios'] 应为 TestFlight/App Store)。
  if (Platform.isIOS) {
    await _openInBrowser(url);
    return;
  }

  final progress = ValueNotifier<double>(0);
  final installing = ValueNotifier<bool>(false);
  var dialogOpen = true;
  void closeDialog() {
    if (context.mounted && dialogOpen) {
      dialogOpen = false;
      Navigator.of(context, rootNavigator: true).pop();
    }
  }

  // 不可关闭的进度框。
  unawaited(showDialog<void>(
    context: context,
    barrierDismissible: false,
    builder: (_) => PopScope(
      canPop: false,
      child: _ProgressDialog(t: t, progress: progress, installing: installing),
    ),
  ));

  try {
    final savePath = await _savePath(url);
    await _download(url, savePath, (p) => progress.value = p);
    installing.value = true;
    await _install(savePath); // Win/macOS 可能在此 exit(0),不再返回
    closeDialog();
    if (Platform.isMacOS && context.mounted) {
      await _showInfo(context, t, t.lang.updateMacReveal);
    }
  } catch (_) {
    closeDialog();
    if (context.mounted) await _showFailed(context, t, url);
  } finally {
    progress.dispose();
    installing.dispose();
  }
}

/// 各平台下载文件的落盘路径。
Future<String> _savePath(String url) async {
  final tmp = await getTemporaryDirectory();
  if (Platform.isWindows) return '${tmp.path}${Platform.pathSeparator}pangolin-update-setup.exe';
  if (Platform.isMacOS) {
    // 下到「下载」目录便于用户在访达里操作;取不到则回退临时目录。
    final dl = await getDownloadsDirectory();
    final dir = dl ?? tmp;
    return '${dir.path}/pangolin-update.zip';
  }
  return '${tmp.path}/pangolin-update.apk'; // Android
}

/// http 流式下载 + 进度回调。失败抛异常(由调用方降级)。
Future<void> _download(String url, String savePath, void Function(double) onProgress) async {
  final client = http.Client();
  try {
    final req = http.Request('GET', Uri.parse(url));
    final resp = await client.send(req);
    if (resp.statusCode != 200) {
      throw HttpException('HTTP ${resp.statusCode}', uri: Uri.parse(url));
    }
    final total = resp.contentLength ?? 0;
    final file = File(savePath);
    final sink = file.openWrite();
    var received = 0;
    try {
      await for (final chunk in resp.stream) {
        received += chunk.length;
        sink.add(chunk);
        if (total > 0) onProgress(received / total);
      }
      await sink.flush();
    } finally {
      await sink.close();
    }
  } finally {
    client.close();
  }
}

/// 下载后触发安装/打开。
Future<void> _install(String path) async {
  if (Platform.isAndroid) {
    await OpenFilex.open(path); // 系统安装器(open_filex 内封 FileProvider)
    return;
  }
  if (Platform.isWindows) {
    await Process.start(path, const [], mode: ProcessStartMode.detached);
    await Future<void>.delayed(const Duration(milliseconds: 400));
    exit(0); // 退出让安装器覆盖
  }
  if (Platform.isMacOS) {
    // 不自动替换 bundle(带系统扩展,风险高):解压 + 访达高亮,提示手动拖入。
    await Process.run('open', <String>[path]); // Archive Utility 解压
    await Process.run('open', <String>['-R', path]); // 访达定位
  }
}

Future<void> _openInBrowser(String url) async {
  final uri = Uri.parse(url);
  if (await canLaunchUrl(uri)) {
    await launchUrl(uri, mode: LaunchMode.externalApplication);
  }
}

Future<void> _showInfo(BuildContext context, AppText t, String msg) {
  final c = context.pangolin;
  return showDialog<void>(
    context: context,
    builder: (ctx) => AlertDialog(
      backgroundColor: c.surface,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(PangolinRadius.xl)),
      content: Text(msg, style: PangolinText.sm.copyWith(color: c.fg2, height: 1.5)),
      actions: [
        TextButton(
          onPressed: () => Navigator.of(ctx).pop(),
          child: Text('OK', style: PangolinText.sm.copyWith(color: c.accent, fontWeight: FontWeight.w700)),
        ),
      ],
    ),
  );
}

Future<void> _showFailed(BuildContext context, AppText t, String url) {
  final c = context.pangolin;
  return showDialog<void>(
    context: context,
    builder: (ctx) => AlertDialog(
      backgroundColor: c.surface,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(PangolinRadius.xl)),
      content: Text(t.lang.updateDownloadFailed, style: PangolinText.sm.copyWith(color: c.fg2, height: 1.5)),
      actions: [
        TextButton(
          onPressed: () => Navigator.of(ctx).pop(),
          child: Text(t.lang.updateCancelBtn, style: PangolinText.sm.copyWith(color: c.fg2, fontWeight: FontWeight.w600)),
        ),
        TextButton(
          onPressed: () async {
            Navigator.of(ctx).pop();
            await _openInBrowser(url);
          },
          child: Text(t.lang.updateOpenBrowser, style: PangolinText.sm.copyWith(color: c.accent, fontWeight: FontWeight.w700)),
        ),
      ],
    ),
  );
}

class _ProgressDialog extends StatelessWidget {
  const _ProgressDialog({required this.t, required this.progress, required this.installing});
  final AppText t;
  final ValueNotifier<double> progress;
  final ValueNotifier<bool> installing;

  @override
  Widget build(BuildContext context) {
    final c = context.pangolin;
    return AlertDialog(
      backgroundColor: c.surface,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(PangolinRadius.xl)),
      title: Row(children: [
        Container(
          width: 34,
          height: 34,
          decoration: BoxDecoration(color: c.accentSubtle, shape: BoxShape.circle),
          child: Icon(PangolinIcons.zap, size: 18, color: c.accent),
        ),
        const SizedBox(width: 12),
        Expanded(
          child: Text(t.updateDownload,
              style: PangolinText.body.copyWith(color: c.fg1, fontWeight: FontWeight.w700)),
        ),
      ]),
      content: ValueListenableBuilder<bool>(
        valueListenable: installing,
        builder: (_, inst, __) => ValueListenableBuilder<double>(
          valueListenable: progress,
          builder: (_, p, __) => Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              ClipRRect(
                borderRadius: BorderRadius.circular(PangolinRadius.full),
                child: LinearProgressIndicator(
                  value: inst || p <= 0 ? null : p,
                  minHeight: 6,
                  backgroundColor: c.bgSubtle,
                  valueColor: AlwaysStoppedAnimation<Color>(c.accent),
                ),
              ),
              const SizedBox(height: 12),
              Text(
                inst ? t.lang.updateInstalling : t.lang.updateDownloadingPercent((p * 100).clamp(0, 100).round()),
                style: PangolinText.sm.copyWith(color: c.fg2),
              ),
            ],
          ),
        ),
      ),
    );
  }
}