import 'package:flutter/material.dart';
import 'package:intl/intl.dart' hide TextDirection;
import 'package:provider/provider.dart';
import '../models/user_model.dart';
import '../providers/user_provider.dart';
import '../theme/app_theme.dart';
import '../widgets/app_sidebar.dart';
import '../widgets/responsive_layout.dart';
import '../widgets/secret_dialog.dart';

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

  @override
  State<UsersScreen> createState() => _UsersScreenState();
}

class _UsersScreenState extends State<UsersScreen> {
  final _searchCtrl = TextEditingController();
  String _search = '';

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      context.read<UserProvider>().loadUsers();
    });
  }

  @override
  void dispose() {
    _searchCtrl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return ResponsiveLayout(
      title: 'کاربران',
      sidebar: const AppSidebar(),
      body: _UsersBody(
        search: _search,
        searchCtrl: _searchCtrl,
        onSearch: (v) => setState(() => _search = v.toLowerCase()),
      ),
    );
  }
}

class _UsersBody extends StatelessWidget {
  final String search;
  final TextEditingController searchCtrl;
  final ValueChanged<String> onSearch;

  const _UsersBody({
    required this.search,
    required this.searchCtrl,
    required this.onSearch,
  });

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.all(24),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          // ── Header ───────────────────────────────────────────────
          Row(
            children: [
              const Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      'مدیریت کاربران',
                      style: TextStyle(
                        fontSize: 24,
                        fontWeight: FontWeight.w800,
                        color: AppTheme.textPrimary,
                      ),
                    ),
                    SizedBox(height: 4),
                    Text(
                      'ایجاد و مدیریت کاربران سیستم',
                      style: TextStyle(
                          fontSize: 14, color: AppTheme.textSecondary),
                    ),
                  ],
                ),
              ),
              ElevatedButton.icon(
                onPressed: () => _showCreateDialog(context),
                icon: const Icon(Icons.person_add_rounded, size: 18),
                label: const Text('کاربر جدید'),
              ),
            ],
          ),
          const SizedBox(height: 20),

          // ── Search ───────────────────────────────────────────────
          TextField(
            controller: searchCtrl,
            onChanged: onSearch,
            decoration: const InputDecoration(
              hintText: 'جستجوی کاربر...',
              prefixIcon: Icon(Icons.search_rounded),
            ),
          ),
          const SizedBox(height: 16),

          // ── Table ────────────────────────────────────────────────
          Expanded(
            child: Consumer<UserProvider>(
              builder: (_, provider, __) {
                if (provider.isLoading) {
                  return const Center(child: CircularProgressIndicator());
                }
                if (provider.status.name == 'error') {
                  return _ErrorView(
                      message: provider.error ?? 'خطا',
                      onRetry: () => provider.loadUsers());
                }

                final filtered = provider.users
                    .where((u) =>
                        search.isEmpty ||
                        u.username.toLowerCase().contains(search) ||
                        u.role.label.toLowerCase().contains(search))
                    .toList();

                if (filtered.isEmpty) {
                  return const _EmptyView(
                    icon: Icons.people_outline_rounded,
                    message: 'کاربری یافت نشد',
                  );
                }

                return _UsersTable(users: filtered);
              },
            ),
          ),
        ],
      ),
    );
  }

  void _showCreateDialog(BuildContext context) {
    showDialog(
      context: context,
      builder: (_) => const _CreateUserDialog(),
    );
  }
}

// ── Create User Dialog ──────────────────────────────────────────────────────

class _CreateUserDialog extends StatefulWidget {
  const _CreateUserDialog();

  @override
  State<_CreateUserDialog> createState() => _CreateUserDialogState();
}

class _CreateUserDialogState extends State<_CreateUserDialog> {
  final _formKey = GlobalKey<FormState>();
  final _usernameCtrl = TextEditingController();
  UserRole _role = UserRole.member;
  bool _loading = false;
  String? _error;

  @override
  void dispose() {
    _usernameCtrl.dispose();
    super.dispose();
  }

  Future<void> _submit() async {
    if (!_formKey.currentState!.validate()) return;
    setState(() {
      _loading = true;
      _error = null;
    });

    final provider = context.read<UserProvider>();
    final result = await provider.createUser(
      _usernameCtrl.text.trim(),
      _role,
    );

    if (!mounted) return;
    setState(() => _loading = false);

    if (result != null) {
      Navigator.of(context).pop();
      await SecretDialog.show(
        context,
        username: result.user.username,
        secret: result.secret,
      );
    } else {
      setState(() => _error = provider.error);
    }
  }

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Row(
        children: [
          Icon(Icons.person_add_rounded, color: AppTheme.primary),
          SizedBox(width: 10),
          Text('ایجاد کاربر جدید'),
        ],
      ),
      content: SizedBox(
        width: 400,
        child: Form(
          key: _formKey,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              TextFormField(
                controller: _usernameCtrl,
                textDirection: TextDirection.ltr,
                decoration: const InputDecoration(
                  labelText: 'نام کاربری',
                  prefixIcon: Icon(Icons.person_outline_rounded),
                ),
                validator: (v) =>
                    (v == null || v.trim().isEmpty) ? 'نام کاربری الزامی است' : null,
              ),
              const SizedBox(height: 16),
              DropdownButtonFormField<UserRole>(
                initialValue: _role,
                decoration: const InputDecoration(
                  labelText: 'نقش',
                  prefixIcon: Icon(Icons.badge_outlined),
                ),
                items: UserRole.values
                    .map((r) => DropdownMenuItem(
                          value: r,
                          child: Text(r.label),
                        ))
                    .toList(),
                onChanged: (v) => setState(() => _role = v!),
              ),
              if (_error != null) ...[
                const SizedBox(height: 12),
                Container(
                  padding: const EdgeInsets.all(10),
                  decoration: BoxDecoration(
                    color: AppTheme.danger.withValues(alpha: 0.08),
                    borderRadius: BorderRadius.circular(8),
                    border: Border.all(color: AppTheme.danger.withValues(alpha: 0.3)),
                  ),
                  child: Text(
                    _error!,
                    style: const TextStyle(color: AppTheme.danger, fontSize: 13),
                  ),
                ),
              ],
            ],
          ),
        ),
      ),
      actions: [
        TextButton(
          onPressed: _loading ? null : () => Navigator.of(context).pop(),
          child: const Text('انصراف'),
        ),
        ElevatedButton(
          onPressed: _loading ? null : _submit,
          child: _loading
              ? const SizedBox(
                  width: 18,
                  height: 18,
                  child: CircularProgressIndicator(
                      color: Colors.white, strokeWidth: 2))
              : const Text('ایجاد'),
        ),
      ],
    );
  }
}

// ── Users Table ──────────────────────────────────────────────────────────────

class _UsersTable extends StatelessWidget {
  final List<UserModel> users;

  const _UsersTable({required this.users});

  @override
  Widget build(BuildContext context) {
    return Card(
      child: ClipRRect(
        borderRadius: BorderRadius.circular(12),
        child: SingleChildScrollView(
          child: SingleChildScrollView(
            scrollDirection: Axis.horizontal,
            child: DataTable(
              columns: const [
                DataColumn(label: Text('نام کاربری')),
                DataColumn(label: Text('نقش')),
                DataColumn(label: Text('وضعیت')),
                DataColumn(label: Text('تاریخ ایجاد')),
                DataColumn(label: Text('عملیات')),
              ],
              rows: users.map((user) => _buildRow(context, user)).toList(),
            ),
          ),
        ),
      ),
    );
  }

  DataRow _buildRow(BuildContext context, UserModel user) {
    return DataRow(
      cells: [
        DataCell(
          Row(
            mainAxisSize: MainAxisSize.min,
            children: [
              CircleAvatar(
                radius: 16,
                backgroundColor: AppTheme.primary.withValues(alpha: 0.12),
                child: Text(
                  user.username[0].toUpperCase(),
                  style: const TextStyle(
                    color: AppTheme.primary,
                    fontSize: 13,
                    fontWeight: FontWeight.w700,
                  ),
                ),
              ),
              const SizedBox(width: 10),
              Text(
                user.username,
                style: const TextStyle(fontWeight: FontWeight.w600),
              ),
            ],
          ),
        ),
        DataCell(_RoleBadge(role: user.role)),
        DataCell(_StatusBadge(isActive: user.isActive)),
        DataCell(
          Text(
            user.createdAt != null
                ? DateFormat('yyyy/MM/dd').format(user.createdAt!)
                : '—',
            style: const TextStyle(color: AppTheme.textSecondary),
          ),
        ),
        DataCell(
          _ResetSecretButton(user: user),
        ),
      ],
    );
  }
}

class _ResetSecretButton extends StatefulWidget {
  final UserModel user;
  const _ResetSecretButton({required this.user});

  @override
  State<_ResetSecretButton> createState() => _ResetSecretButtonState();
}

class _ResetSecretButtonState extends State<_ResetSecretButton> {
  bool _loading = false;

  Future<void> _reset() async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (_) => AlertDialog(
        title: const Text('تأیید ریست رمز'),
        content: Text(
            'آیا مطمئن هستید که می‌خواهید رمز «${widget.user.username}» را ریست کنید؟'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('انصراف'),
          ),
          ElevatedButton(
            onPressed: () => Navigator.pop(context, true),
            style: ElevatedButton.styleFrom(backgroundColor: AppTheme.warning),
            child: const Text('ریست'),
          ),
        ],
      ),
    );

    if (confirmed != true || !mounted) return;
    setState(() => _loading = true);

    final provider = context.read<UserProvider>();
    final secret = await provider.resetSecret(widget.user.id);
    if (!mounted) return;
    setState(() => _loading = false);

    if (secret != null) {
      await SecretDialog.show(
        context,
        username: widget.user.username,
        secret: secret,
        isReset: true,
      );
    } else if (provider.error != null) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(provider.error!),
          backgroundColor: AppTheme.danger,
        ),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    if (_loading) {
      return const SizedBox(
          width: 18,
          height: 18,
          child: CircularProgressIndicator(strokeWidth: 2));
    }
    return TextButton.icon(
      onPressed: _reset,
      icon: const Icon(Icons.lock_reset_rounded, size: 16),
      label: const Text('ریست رمز'),
      style: TextButton.styleFrom(foregroundColor: AppTheme.warning),
    );
  }
}

// ── Shared small widgets ─────────────────────────────────────────────────────

class _RoleBadge extends StatelessWidget {
  final UserRole role;
  const _RoleBadge({required this.role});

  @override
  Widget build(BuildContext context) {
    final color = AppTheme.roleColor(role.name);
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
      decoration: BoxDecoration(
        color: color.withValues(alpha: 0.12),
        borderRadius: BorderRadius.circular(20),
      ),
      child: Text(
        role.label,
        style: TextStyle(
          color: color,
          fontSize: 12,
          fontWeight: FontWeight.w600,
        ),
      ),
    );
  }
}

class _StatusBadge extends StatelessWidget {
  final bool isActive;
  const _StatusBadge({required this.isActive});

  @override
  Widget build(BuildContext context) {
    final color = isActive ? AppTheme.success : AppTheme.danger;
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
      decoration: BoxDecoration(
        color: color.withValues(alpha: 0.12),
        borderRadius: BorderRadius.circular(20),
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          Container(
            width: 6,
            height: 6,
            decoration: BoxDecoration(color: color, shape: BoxShape.circle),
          ),
          const SizedBox(width: 5),
          Text(
            isActive ? 'فعال' : 'غیرفعال',
            style: TextStyle(
              color: color,
              fontSize: 12,
              fontWeight: FontWeight.w600,
            ),
          ),
        ],
      ),
    );
  }
}

class _EmptyView extends StatelessWidget {
  final IconData icon;
  final String message;
  const _EmptyView({required this.icon, required this.message});

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Icon(icon, size: 64, color: AppTheme.border),
          const SizedBox(height: 16),
          Text(
            message,
            style: const TextStyle(
                color: AppTheme.textSecondary, fontSize: 16),
          ),
        ],
      ),
    );
  }
}

class _ErrorView extends StatelessWidget {
  final String message;
  final VoidCallback onRetry;
  const _ErrorView({required this.message, required this.onRetry});

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          const Icon(Icons.error_outline_rounded,
              size: 64, color: AppTheme.danger),
          const SizedBox(height: 16),
          Text(message,
              style: const TextStyle(color: AppTheme.textSecondary)),
          const SizedBox(height: 16),
          ElevatedButton.icon(
            onPressed: onRetry,
            icon: const Icon(Icons.refresh_rounded),
            label: const Text('تلاش مجدد'),
          ),
        ],
      ),
    );
  }
}