import 'dart:io';

import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:miaoji_zhang/shared/api/api_client.dart';
import 'package:miaoji_zhang/shared/api/auth_api.dart';
import 'package:miaoji_zhang/shared/theme/app_theme.dart';
import 'package:miaoji_zhang/shared/services/session_store.dart';
import 'package:miaoji_zhang/shared/widgets/app_controls.dart';
import 'package:path_provider/path_provider.dart';
import 'package:share_plus/share_plus.dart';

class AccountDataPage extends StatefulWidget {
  const AccountDataPage({super.key});

  @override
  State<AccountDataPage> createState() => _AccountDataPageState();
}

class _AccountDataPageState extends State<AccountDataPage> {
  UserProfile? _profile;
  bool _busy = false;

  @override
  void initState() {
    super.initState();
    _cleanupStaleExports();
    _load();
  }

  Future<void> _cleanupStaleExports() async {
    try {
      final directory = await getTemporaryDirectory();
      final cutoff = DateTime.now().subtract(const Duration(hours: 24));
      await for (final entity in directory.list()) {
        if (entity is! File ||
            !entity.path.contains('jizhi-export-') ||
            !entity.path.endsWith('.zip')) {
          continue;
        }
        final modified = await entity.lastModified();
        if (modified.isBefore(cutoff)) await entity.delete();
      }
    } catch (_) {
      // Export cleanup is best-effort and must not block the settings page.
    }
  }

  Future<void> _load() async {
    try {
      final profile = await AuthApi.me();
      if (mounted) setState(() => _profile = profile);
    } catch (error) {
      if (mounted) _showError(error);
    }
  }

  Future<String?> _ask({
    required String title,
    required String label,
    bool obscure = false,
    String? initialValue,
    String? subtitle,
  }) {
    return showJzTextInputSheet(
      context,
      title: title,
      label: label,
      subtitle: subtitle,
      initialValue: initialValue,
      obscureText: obscure,
      maxLength: obscure ? null : 32,
    );
  }

  Future<void> _editNickname() async {
    final nickname = await _ask(
      title: '修改昵称',
      label: '昵称',
      initialValue: _profile?.nickname ?? '',
    );
    if (nickname == null) return;
    try {
      final profile = await AuthApi.updateProfile(nickname);
      if (mounted) setState(() => _profile = profile);
    } catch (error) {
      if (mounted) _showError(error);
    }
  }

  Future<void> _changePassword() async {
    final current = await _ask(title: '验证当前密码', label: '当前密码', obscure: true);
    if (current == null || current.isEmpty) return;
    final next = await _ask(
      title: '设置新密码',
      label: '新密码（至少 6 位）',
      obscure: true,
    );
    if (next == null || next.isEmpty) return;
    try {
      await AuthApi.changePassword(current, next);
      if (mounted) {
        ScaffoldMessenger.of(
          context,
        ).showSnackBar(const SnackBar(content: Text('密码已修改，其他设备已退出登录')));
      }
    } catch (error) {
      if (mounted) _showError(error);
    }
  }

  Future<void> _export() async {
    File? temporaryFile;
    setState(() => _busy = true);
    try {
      final bytes = await AuthApi.exportData();
      if (bytes.isEmpty) throw StateError('导出文件为空');
      final directory = await getTemporaryDirectory();
      final name =
          'jizhi-export-' +
          DateTime.now().millisecondsSinceEpoch.toString() +
          '.zip';
      temporaryFile = File(directory.path + Platform.pathSeparator + name);
      await temporaryFile.writeAsBytes(bytes, flush: true);
      await SharePlus.instance.share(
        ShareParams(
          files: [XFile(temporaryFile.path, mimeType: 'application/zip')],
          fileNameOverrides: [name],
          title: '记之数据导出',
          subject: '记之数据导出',
        ),
      );
    } catch (error) {
      if (mounted) _showError(error);
    } finally {
      if (temporaryFile != null) {
        try {
          if (await temporaryFile.exists()) await temporaryFile.delete();
        } catch (_) {
          // The operating system can briefly retain a shared file handle.
        }
      }
      if (mounted) setState(() => _busy = false);
    }
  }

  Future<void> _closeAccount() async {
    final understood = await showJzConfirmSheet(
      context,
      title: '申请注销账号',
      message:
          '提交后会退出所有设备，并进入 15 天后悔期。期间使用正确账号密码登录会自动取消注销；到期后账本、账单、预算和聊天记录将永久删除。',
      confirmLabel: '我已了解',
      destructive: true,
      content: Container(
        width: double.infinity,
        padding: const EdgeInsets.all(12),
        decoration: BoxDecoration(
          color: context.jz.warningBackground,
          borderRadius: BorderRadius.circular(12),
        ),
        child: Text(
          '建议先导出数据。后悔期结束后，数据无法恢复。',
          style: TextStyle(
            fontSize: 11.5,
            color: context.jz.text2,
            height: 1.5,
          ),
        ),
      ),
    );
    if (!understood || !mounted) return;

    final password = await _ask(
      title: '验证身份',
      label: '输入登录密码',
      obscure: true,
      subtitle: '这是第二次确认，用于验证账号所有权',
    );
    if (password == null || password.isEmpty || !mounted) return;

    final confirmation = await _ask(
      title: '最后确认',
      label: '输入“注销账号”',
      subtitle: '提交后立即退出，15 天内重新登录可恢复账号',
    );
    if (confirmation == null) return;
    if (confirmation.trim() != '注销账号') {
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(const SnackBar(content: Text('请输入完整的“注销账号”')));
      return;
    }

    setState(() => _busy = true);
    try {
      final scheduledAt = await AuthApi.requestAccountClosure(
        password,
        confirmation,
      );
      if (!mounted) return;
      final notice =
          '注销申请已提交，将于 ' +
          scheduledAt.month.toString() +
          '月' +
          scheduledAt.day.toString() +
          '日永久删除';
      context.go(
        Uri(path: '/login', queryParameters: {'notice': notice}).toString(),
      );
    } catch (error) {
      if (mounted) _showError(error);
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

  void _showError(Object error) {
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(SnackBar(content: Text(apiErrorMessage(error))));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('账号与数据')),
      body: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          Card(
            child: Column(
              children: [
                ListTile(
                  title: Text('昵称'),
                  subtitle: Text(_profile?.nickname ?? '未设置'),
                  trailing: Icon(Icons.chevron_right_rounded),
                  onTap: _editNickname,
                ),
                if (!SessionStore.instance.isGuest) ...[
                  Divider(height: 1),
                  ListTile(
                    title: Text('修改密码'),
                    trailing: Icon(Icons.chevron_right_rounded),
                    onTap: _changePassword,
                  ),
                ],
              ],
            ),
          ),
          SizedBox(height: 12),
          Card(
            child: ListTile(
              leading: Icon(Icons.archive_outlined, color: AppTheme.primary),
              title: Text('导出全部数据'),
              subtitle: Text('ZIP 包含交易/预算 CSV 和完整 JSON，不含密码与密钥'),
              trailing: _busy
                  ? SizedBox(
                      width: 18,
                      height: 18,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : Icon(Icons.ios_share_rounded),
              onTap: _busy ? null : _export,
            ),
          ),
          SizedBox(height: 12),
          Card(
            child: Column(
              children: [
                _legalTile('用户协议', 'terms'),
                Divider(height: 1),
                _legalTile('隐私政策', 'privacy'),
                Divider(height: 1),
                _legalTile('权限用途说明', 'permissions'),
                Divider(height: 1),
                _legalTile('第三方 SDK 清单', 'sdk'),
              ],
            ),
          ),
          SizedBox(height: 12),
          if (!SessionStore.instance.isGuest)
            Card(
              child: ListTile(
                leading: Icon(Icons.person_off_outlined, color: AppTheme.red),
                title: Text('注销账号', style: TextStyle(color: AppTheme.red)),
                subtitle: Text('15 天后永久删除，可在后悔期内登录恢复'),
                trailing: Icon(
                  Icons.chevron_right_rounded,
                  color: AppTheme.red,
                ),
                onTap: _busy ? null : _closeAccount,
              ),
            ),
        ],
      ),
    );
  }

  Widget _legalTile(String title, String kind) => ListTile(
    leading: Icon(Icons.verified_user_outlined, color: AppTheme.primary),
    title: Text(title),
    trailing: Icon(Icons.chevron_right_rounded),
    onTap: () => context.push('/legal/' + kind),
  );
}