import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter_markdown_plus/flutter_markdown_plus.dart';
import 'package:url_launcher/url_launcher.dart';
import 'package:miaoji_zhang/shared/theme/app_theme.dart';
import 'package:miaoji_zhang/shared/update/update_config.dart';
import 'package:miaoji_zhang/shared/update/update_downloader.dart';
import 'package:miaoji_zhang/shared/update/update_installer.dart';
import 'package:miaoji_zhang/shared/update/update_models.dart';
import 'package:miaoji_zhang/shared/version.dart';
import 'package:miaoji_zhang/shared/widgets/app_controls.dart';

Future<void> showUpdatePrompt(
  BuildContext context, {
  required AppRelease release,
  required bool forced,
  required Future<void> Function() onIgnore,
}) {
  return showModalBottomSheet<void>(
    context: context,
    useRootNavigator: true,
    isScrollControlled: true,
    isDismissible: false,
    enableDrag: false,
    backgroundColor: Colors.transparent,
    builder: (_) =>
        UpdatePromptSheet(release: release, forced: forced, onIgnore: onIgnore),
  );
}

class UpdatePromptSheet extends StatefulWidget {
  final AppRelease release;
  final bool forced;
  final Future<void> Function() onIgnore;

  const UpdatePromptSheet({
    super.key,
    required this.release,
    required this.forced,
    required this.onIgnore,
  });

  @override
  State<UpdatePromptSheet> createState() => _UpdatePromptSheetState();
}

class _UpdatePromptSheetState extends State<UpdatePromptSheet> {
  final _downloader = UpdateDownloader();
  UpdateDownloadProgress? _progress;
  bool _working = false;
  String? _status;
  String? _error;
  String? _downloadedPath;

  @override
  void dispose() {
    _downloader.cancel();
    super.dispose();
  }

  Future<void> _ignore() async {
    if (_working) return;
    await widget.onIgnore();
    if (mounted) Navigator.pop(context);
  }

  Future<void> _update() async {
    if (_working) return;
    final uri = Uri.tryParse(widget.release.downloadUrl);
    if (uri == null || uri.scheme != 'https' || uri.host.isEmpty) {
      setState(() => _error = '更新地址无效，必须使用 HTTPS');
      return;
    }
    if (!UpdateConfig.canInstallInApp) {
      setState(() {
        _working = true;
        _error = null;
        _status = '正在打开更新页面…';
      });
      try {
        final opened = await launchUrl(
          uri,
          mode: LaunchMode.externalApplication,
        );
        if (!opened) throw StateError('无法打开更新页面');
        if (!widget.forced && mounted) Navigator.pop(context);
        if (mounted && widget.forced) {
          setState(() => _status = '更新页面已打开，完成更新后重新打开记之');
        }
      } catch (_) {
        if (mounted) setState(() => _error = '无法打开更新页面，请稍后重试');
      } finally {
        if (mounted) setState(() => _working = false);
      }
      return;
    }

    setState(() {
      _working = true;
      _error = null;
      _status = '正在下载更新包…';
      _progress = null;
    });
    String? path;
    try {
      final cachedPath = _downloadedPath;
      if (cachedPath != null && await File(cachedPath).exists()) {
        path = cachedPath;
      } else {
        _downloadedPath = null;
        path = await _downloader.downloadAndVerify(
          widget.release,
          onProgress: (progress) {
            if (!mounted) return;
            setState(() {
              _progress = progress;
              _status = '正在下载更新包…';
            });
          },
        );
        _downloadedPath = path;
      }
      if (!mounted) return;
      setState(() {
        _status = '校验完成，正在打开安装界面…';
        _progress = null;
      });
      final status = await UpdateInstaller.install(
        path: path,
        expectedBuild: widget.release.buildNumber,
      );
      if (!mounted) return;
      setState(() {
        _status = switch (status) {
          ApkInstallStatus.launched => '安装界面已打开，完成后重新启动记之',
          ApkInstallStatus.permissionRequested => '请允许安装未知应用，返回后将继续安装',
          ApkInstallStatus.unsupported => '当前设备无法调起安装，请重新下载',
        };
        if (status == ApkInstallStatus.unsupported) {
          _error = _status;
        }
      });
      if (status == ApkInstallStatus.launched) {
        await _downloader.scheduleCleanup(path);
      } else if (status == ApkInstallStatus.unsupported) {
        await _downloader.deleteFile(path);
        _downloadedPath = null;
      }
    } on UpdateDownloadException catch (error) {
      if (mounted) setState(() => _error = error.message);
    } catch (_) {
      if (mounted) setState(() => _error = '更新失败，请重新尝试');
    } finally {
      if (mounted) setState(() => _working = false);
    }
  }

  void _cancelDownload() {
    _downloader.cancel();
    setState(() => _status = '正在取消下载…');
  }

  @override
  Widget build(BuildContext context) {
    final release = widget.release;
    return PopScope(
      canPop: false,
      child: SafeArea(
        child: Container(
          constraints: BoxConstraints(
            maxHeight: MediaQuery.sizeOf(context).height * 0.84,
          ),
          padding: const EdgeInsets.fromLTRB(20, 0, 20, 18),
          decoration: BoxDecoration(
            color: context.jz.card,
            borderRadius: const BorderRadius.vertical(top: Radius.circular(24)),
          ),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              JzSheetHeader(
                title: widget.forced ? '必须更新后继续使用' : '发现新版本',
                subtitle:
                    'v${release.versionName} (${release.buildNumber}) · 当前 ${AppVersion.display}',
              ),
              if (widget.forced)
                Container(
                  width: double.infinity,
                  margin: const EdgeInsets.only(top: 12),
                  padding: const EdgeInsets.symmetric(
                    horizontal: 12,
                    vertical: 10,
                  ),
                  decoration: BoxDecoration(
                    color: context.jz.warningBackground,
                    borderRadius: BorderRadius.circular(12),
                    border: Border.all(
                      color: AppTheme.orange.withValues(alpha: 0.35),
                    ),
                  ),
                  child: Text(
                    '此版本已停止支持，更新完成前暂时不能进入 App。',
                    style: TextStyle(
                      fontSize: 12,
                      color: context.jz.text2,
                      height: 1.45,
                    ),
                  ),
                ),
              const SizedBox(height: 14),
              Flexible(
                child: Container(
                  width: double.infinity,
                  padding: const EdgeInsets.all(14),
                  decoration: BoxDecoration(
                    color: context.jz.background,
                    borderRadius: BorderRadius.circular(14),
                    border: Border.all(color: context.jz.line),
                  ),
                  child: SingleChildScrollView(
                    child: MarkdownBody(
                      data: release.releaseNotes.isEmpty
                          ? '本次更新包含体验优化与问题修复。'
                          : release.releaseNotes,
                      selectable: true,
                      styleSheet: MarkdownStyleSheet(
                        p: TextStyle(
                          fontSize: 13,
                          color: context.jz.text2,
                          height: 1.65,
                        ),
                        h1: TextStyle(
                          fontSize: 17,
                          fontWeight: FontWeight.w800,
                          color: context.jz.text,
                        ),
                        h2: TextStyle(
                          fontSize: 15,
                          fontWeight: FontWeight.w800,
                          color: context.jz.text,
                        ),
                        listBullet: TextStyle(
                          fontSize: 13,
                          color: AppTheme.primaryDeep,
                        ),
                        code: TextStyle(
                          fontSize: 12,
                          color: context.jz.text,
                          backgroundColor: context.jz.card,
                        ),
                        blockquoteDecoration: BoxDecoration(
                          color: context.jz.card,
                          borderRadius: BorderRadius.circular(8),
                          border: const Border(
                            left: BorderSide(color: AppTheme.ai, width: 3),
                          ),
                        ),
                      ),
                    ),
                  ),
                ),
              ),
              if (_progress != null || _status != null || _error != null) ...[
                const SizedBox(height: 14),
                if (_progress != null) _UpdateProgressBar(progress: _progress!),
                if (_progress != null) const SizedBox(height: 8),
                Align(
                  alignment: Alignment.centerLeft,
                  child: Text(
                    _error ?? _status ?? '',
                    style: TextStyle(
                      fontSize: 11.5,
                      color: _error == null ? context.jz.text2 : AppTheme.red,
                    ),
                  ),
                ),
              ],
              const SizedBox(height: 18),
              if (_working && _downloader.isDownloading && !widget.forced)
                SizedBox(
                  width: double.infinity,
                  child: JzActionButton(
                    label: '取消下载',
                    secondary: true,
                    onPressed: _cancelDownload,
                  ),
                )
              else
                Row(
                  children: [
                    if (!widget.forced) ...[
                      Expanded(
                        child: JzActionButton(
                          label: '忽略此版本',
                          secondary: true,
                          onPressed: _working ? null : _ignore,
                        ),
                      ),
                      const SizedBox(width: 10),
                    ],
                    Expanded(
                      child: JzActionButton(
                        label: UpdateConfig.canInstallInApp
                            ? (_downloadedPath == null ? '下载并安装' : '继续安装')
                            : '立即更新',
                        loading: _working,
                        onPressed: _working ? null : _update,
                      ),
                    ),
                  ],
                ),
            ],
          ),
        ),
      ),
    );
  }
}

class _UpdateProgressBar extends StatelessWidget {
  final UpdateDownloadProgress progress;
  const _UpdateProgressBar({required this.progress});

  @override
  Widget build(BuildContext context) {
    final fraction = progress.fraction ?? 0;
    return Column(
      children: [
        ClipRRect(
          borderRadius: BorderRadius.circular(4),
          child: SizedBox(
            height: 7,
            child: Stack(
              fit: StackFit.expand,
              children: [
                ColoredBox(color: context.jz.line),
                FractionallySizedBox(
                  alignment: Alignment.centerLeft,
                  widthFactor: fraction,
                  child: const ColoredBox(color: AppTheme.primary),
                ),
              ],
            ),
          ),
        ),
        const SizedBox(height: 6),
        Row(
          children: [
            Text(
              progress.total > 0
                  ? '${(fraction * 100).toStringAsFixed(0)}%'
                  : _formatBytes(progress.received),
              style: TextStyle(fontSize: 10.5, color: context.jz.text3),
            ),
            const Spacer(),
            Text(
              '${_formatBytes(progress.bytesPerSecond.round())}/s',
              style: TextStyle(fontSize: 10.5, color: context.jz.text3),
            ),
          ],
        ),
      ],
    );
  }
}

String _formatBytes(int bytes) {
  if (bytes >= 1024 * 1024) {
    return '${(bytes / 1024 / 1024).toStringAsFixed(1)} MB';
  }
  if (bytes >= 1024) {
    return '${(bytes / 1024).toStringAsFixed(1)} KB';
  }
  return '$bytes B';
}