import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:intl/intl.dart';
import 'package:url_launcher/url_launcher.dart';
import '../../core/config/app_info.dart';
import '../../core/theme/app_theme.dart';
import '../../core/update/app_updater.dart';
import '../../core/utils/dialog_util.dart';
import '../../providers/license_provider.dart';
import '../../providers/update_provider.dart';

/// 「关于我们」独立页面（左侧菜单项）。原为系统设置里的「关于」Tab。
class AboutScreen extends ConsumerStatefulWidget {
  const AboutScreen({super.key});

  @override
  ConsumerState<AboutScreen> createState() => _AboutScreenState();
}

class _AboutScreenState extends ConsumerState<AboutScreen> {
  @override
  Widget build(BuildContext context) {
    final appVersion = ref.watch(appVersionProvider).valueOrNull ?? 'v1.0.0';
    final updateInfo = ref.watch(updateProvider).valueOrNull;
    final licenseAsync = ref.watch(licenseProvider);

    return SingleChildScrollView(
      padding: const EdgeInsets.all(24),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          // ── 版本信息 ──
          _AboutSection(
            title: '版本信息',
            children: [
              _AboutRow(label: '当前版本', value: appVersion),
              if (updateInfo != null && updateInfo.hasUpdate)
                _AboutRow(
                  label: '最新版本',
                  value: 'v${updateInfo.latestVersion}',
                  valueColor: AppTheme.success,
                  trailing: TextButton(
                    onPressed: () => startInAppUpdate(context, updateInfo),
                    child: const Text('立即更新'),
                  ),
                )
              else
                _AboutRow(
                  label: '最新版本',
                  value: updateInfo != null ? '已是最新' : '检查中…',
                  valueColor: AppTheme.textSecondary,
                  trailing: TextButton(
                    onPressed: () async {
                      final messenger = ScaffoldMessenger.of(context);
                      messenger.showSnackBar(
                          const SnackBar(content: Text('正在检查更新…')));
                      await ref.read(updateProvider.notifier).forceCheck();
                      if (!context.mounted) return;
                      final r = ref.read(updateProvider).valueOrNull;
                      messenger.hideCurrentSnackBar();
                      final String msg;
                      if (r == null) {
                        msg = '检查更新失败，请检查网络';
                      } else if (r.hasUpdate) {
                        msg = '发现新版本 v${r.latestVersion}';
                      } else {
                        msg = '已是最新版本（v${r.latestVersion}）';
                      }
                      messenger.showSnackBar(SnackBar(content: Text(msg)));
                    },
                    child: const Text('检查更新'),
                  ),
                ),
            ],
          ),
          const SizedBox(height: 20),

          // ── 授权信息 ──
          _AboutSection(
            title: '授权信息',
            children: [
              licenseAsync.when(
                loading: () => const _AboutRow(label: '授权状态', value: '加载中…'),
                error: (_, __) =>
                    const _AboutRow(label: '授权状态', value: '暂无授权信息'),
                data: (lic) {
                  if (lic == null) {
                    return const _AboutRow(label: '授权状态', value: '未激活');
                  }
                  return Column(
                    children: [
                      _AboutRow(label: '授权类型', value: lic.typeLabel),
                      _AboutRow(
                        label: '授权状态',
                        value: lic.isExpired
                            ? '已过期'
                            : lic.isActive
                                ? '正常'
                                : '已停用',
                        valueColor: lic.isExpired
                            ? AppTheme.danger
                            : lic.isActive
                                ? AppTheme.success
                                : AppTheme.textSecondary,
                      ),
                      if (lic.expiresAt != null)
                        _AboutRow(
                          label: '到期时间',
                          value: DateFormat('yyyy-MM-dd').format(lic.expiresAt!),
                          trailing: lic.daysRemaining != null &&
                                  lic.daysRemaining! <= 30
                              ? Chip(
                                  label: Text(
                                    lic.isExpired
                                        ? '已过期'
                                        : '剩余 ${lic.daysRemaining} 天',
                                    style: const TextStyle(
                                        fontSize: 11, color: Colors.white),
                                  ),
                                  backgroundColor: lic.isExpired
                                      ? AppTheme.danger
                                      : Colors.orange,
                                  padding: EdgeInsets.zero,
                                  materialTapTargetSize:
                                      MaterialTapTargetSize.shrinkWrap,
                                )
                              : null,
                        )
                      else
                        const _AboutRow(label: '到期时间', value: '永久有效'),
                      if (lic.activatedAt != null)
                        _AboutRow(
                          label: '激活时间',
                          value: DateFormat('yyyy-MM-dd')
                              .format(lic.activatedAt!),
                        ),
                    ],
                  );
                },
              ),
              const SizedBox(height: 8),
              Row(
                children: [
                  OutlinedButton.icon(
                    onPressed: () => _showRenewDialog(),
                    icon: const Icon(Icons.card_membership, size: 16),
                    label: const Text('续费 / 升级授权'),
                  ),
                ],
              ),
            ],
          ),
          const SizedBox(height: 20),

          // ── 关于我们 ──
          _AboutSection(
            title: '关于我们',
            children: [
              _AboutRow(label: '服务商', value: AppInfo.provider),
              _AboutRow(label: '官方网站', value: AppInfo.website),
              _AboutRow(label: '联系邮箱', value: AppInfo.email),
              const _AboutRow(label: '技术支持', value: '周一至周五 9:00 - 18:00'),
              const SizedBox(height: 8),
              Wrap(
                spacing: 8,
                children: [
                  OutlinedButton.icon(
                    onPressed: () async {
                      final uri = Uri.parse(
                          'mailto:${AppInfo.email}?subject=酒库管理系统咨询');
                      if (await canLaunchUrl(uri)) launchUrl(uri);
                    },
                    icon: const Icon(Icons.email_outlined, size: 16),
                    label: const Text('发送邮件'),
                  ),
                ],
              ),
            ],
          ),
          const SizedBox(height: 20),

          // ── 意见反馈 ──
          _AboutSection(
            title: '意见反馈',
            children: [
              const _AboutRow(
                label: '问题反馈',
                value: '遇到 Bug 或有功能建议，欢迎告知我们',
              ),
              const SizedBox(height: 8),
              Wrap(
                spacing: 8,
                children: [
                  ElevatedButton.icon(
                    onPressed: () => _showFeedbackDialog(isBug: true),
                    icon: const Icon(Icons.bug_report_outlined, size: 16),
                    label: const Text('反馈 Bug'),
                  ),
                  OutlinedButton.icon(
                    onPressed: () => _showFeedbackDialog(isBug: false),
                    icon: const Icon(Icons.lightbulb_outline, size: 16),
                    label: const Text('功能建议'),
                  ),
                ],
              ),
            ],
          ),
        ],
      ),
    );
  }

  void _showRenewDialog() {
    showAppDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('续费 / 升级授权'),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text('请联系我们获取续费报价：'),
            const SizedBox(height: 12),
            SelectableText('📧 ${AppInfo.email}',
                style: const TextStyle(fontSize: 13)),
          ],
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx),
            child: const Text('关闭'),
          ),
          ElevatedButton(
            onPressed: () async {
              await Clipboard.setData(ClipboardData(text: AppInfo.email));
              if (ctx.mounted) {
                Navigator.pop(ctx);
                ScaffoldMessenger.of(context).showSnackBar(
                  const SnackBar(content: Text('邮箱已复制到剪贴板')),
                );
              }
            },
            child: const Text('复制邮箱'),
          ),
        ],
      ),
    );
  }

  void _showFeedbackDialog({required bool isBug}) {
    final ctrl = TextEditingController();
    showAppDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(isBug ? '反馈 Bug' : '功能建议'),
        content: SizedBox(
          width: 400,
          child: TextField(
            controller: ctrl,
            maxLines: 6,
            decoration: InputDecoration(
              hintText: isBug ? '请描述问题的复现步骤和预期行为…' : '请描述您希望增加的功能…',
              border: const OutlineInputBorder(),
            ),
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx),
            child: const Text('取消'),
          ),
          ElevatedButton(
            onPressed: () async {
              final subject = Uri.encodeComponent(isBug ? 'Bug反馈' : '功能建议');
              final body = Uri.encodeComponent(ctrl.text);
              final uri = Uri.parse(
                  'mailto:${AppInfo.email}?subject=$subject&body=$body');
              if (await canLaunchUrl(uri)) launchUrl(uri);
              if (ctx.mounted) Navigator.pop(ctx);
            },
            child: const Text('通过邮件发送'),
          ),
        ],
      ),
    );
  }
}

// ── 关于页辅助 widgets ──────────────────────────────────────

class _AboutSection extends StatelessWidget {
  final String title;
  final List<Widget> children;
  const _AboutSection({required this.title, required this.children});

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(20),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(title,
                style: const TextStyle(
                    fontSize: 14,
                    fontWeight: FontWeight.w600,
                    color: AppTheme.primaryDark)),
            const Divider(height: 24),
            ...children,
          ],
        ),
      ),
    );
  }
}

class _AboutRow extends StatelessWidget {
  final String label;
  final String value;
  final Color? valueColor;
  final Widget? trailing;

  const _AboutRow({
    required this.label,
    required this.value,
    this.valueColor,
    this.trailing,
  });

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 6),
      child: Row(
        children: [
          SizedBox(
            width: 88,
            child: Text(label,
                style: const TextStyle(
                    fontSize: 13, color: AppTheme.textSecondary)),
          ),
          Expanded(
            child: Text(value,
                style: TextStyle(
                    fontSize: 13,
                    color: valueColor ?? AppTheme.textPrimary,
                    fontWeight: FontWeight.w500)),
          ),
          if (trailing != null) trailing!,
        ],
      ),
    );
  }
}