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

class GroupDetailScreen extends StatefulWidget {
  final String groupId;

  const GroupDetailScreen({super.key, required this.groupId});

  @override
  State<GroupDetailScreen> createState() => _GroupDetailScreenState();
}

class _GroupDetailScreenState extends State<GroupDetailScreen> {
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      final groups = context.read<GroupProvider>();
      groups.loadGroupMembers(widget.groupId);
      if (groups.groups.isEmpty) groups.loadGroups();
      context.read<UserProvider>().loadUsers();
    });
  }

  @override
  Widget build(BuildContext context) {
    return Consumer<GroupProvider>(builder: (_, groupProvider, __) {
      final group = groupProvider.groups
          .where((g) => g.id == widget.groupId)
          .firstOrNull;

      return ResponsiveLayout(
        title: group?.name ?? 'جزئیات گروه',
        sidebar: const AppSidebar(),
        body: _GroupDetailBody(
          groupId: widget.groupId,
          groupName: group?.name ?? '...',
          groupDescription: group?.description,
          isActive: group?.isActive ?? true,
          createdAt: group?.createdAt,
        ),
      );
    });
  }
}

class _GroupDetailBody extends StatelessWidget {
  final String groupId;
  final String groupName;
  final String? groupDescription;
  final bool isActive;
  final DateTime? createdAt;

  const _GroupDetailBody({
    required this.groupId,
    required this.groupName,
    required this.groupDescription,
    required this.isActive,
    required this.createdAt,
  });

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      padding: const EdgeInsets.all(24),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          // ── Back button + Header ──────────────────────────────────
          Row(
            children: [
              IconButton(
                onPressed: () => context.go('/groups'),
                icon: const Icon(Icons.arrow_back_rounded),
                tooltip: 'بازگشت',
              ),
              const SizedBox(width: 8),
              Expanded(
                child: Text(
                  groupName,
                  style: const TextStyle(
                    fontSize: 24,
                    fontWeight: FontWeight.w800,
                    color: AppTheme.textPrimary,
                  ),
                ),
              ),
              ElevatedButton.icon(
                onPressed: () => _showAddMemberDialog(context),
                icon: const Icon(Icons.person_add_rounded, size: 18),
                label: const Text('افزودن عضو'),
              ),
            ],
          ),
          const SizedBox(height: 20),

          // ── Group info card ───────────────────────────────────────
          Card(
            child: Padding(
              padding: const EdgeInsets.all(20),
              child: Row(
                children: [
                  Container(
                    width: 56,
                    height: 56,
                    decoration: BoxDecoration(
                      color: const Color(0xFF7C3AED).withValues(alpha: 0.12),
                      borderRadius: BorderRadius.circular(14),
                    ),
                    child: const Icon(
                      Icons.groups_rounded,
                      color: Color(0xFF7C3AED),
                      size: 28,
                    ),
                  ),
                  const SizedBox(width: 16),
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Row(
                          children: [
                            Text(
                              groupName,
                              style: const TextStyle(
                                fontSize: 18,
                                fontWeight: FontWeight.w700,
                                color: AppTheme.textPrimary,
                              ),
                            ),
                            const SizedBox(width: 10),
                            _StatusBadge(isActive: isActive),
                          ],
                        ),
                        if (groupDescription != null) ...[
                          const SizedBox(height: 4),
                          Text(
                            groupDescription!,
                            style: const TextStyle(
                              color: AppTheme.textSecondary,
                              fontSize: 14,
                            ),
                          ),
                        ],
                        const SizedBox(height: 4),
                        Text(
                          createdAt != null
                              ? 'ایجاد شده در ${DateFormat('yyyy/MM/dd').format(createdAt!)}'
                              : '',
                          style: const TextStyle(
                            color: AppTheme.textSecondary,
                            fontSize: 12,
                          ),
                        ),
                      ],
                    ),
                  ),
                ],
              ),
            ),
          ),
          const SizedBox(height: 24),

          // ── Members section ───────────────────────────────────────
          const Text(
            'اعضای گروه',
            style: TextStyle(
              fontSize: 18,
              fontWeight: FontWeight.w700,
              color: AppTheme.textPrimary,
            ),
          ),
          const SizedBox(height: 12),
          _MembersTable(groupId: groupId),
        ],
      ),
    );
  }

  void _showAddMemberDialog(BuildContext context) {
    showDialog(
      context: context,
      builder: (_) => _AddMemberDialog(groupId: groupId),
    );
  }
}

// ── Add Member Dialog ────────────────────────────────────────────────────────

class _AddMemberDialog extends StatefulWidget {
  final String groupId;
  const _AddMemberDialog({required this.groupId});

  @override
  State<_AddMemberDialog> createState() => _AddMemberDialogState();
}

class _AddMemberDialogState extends State<_AddMemberDialog> {
  UserModel? _selectedUser;
  GroupRole _role = GroupRole.member;
  bool _loading = false;
  String? _error;

  Future<void> _submit() async {
    if (_selectedUser == null) {
      setState(() => _error = 'لطفاً یک کاربر انتخاب کنید');
      return;
    }
    setState(() {
      _loading = true;
      _error = null;
    });

    final provider = context.read<GroupProvider>();
    final currentMembers = provider.membersOf(widget.groupId);
    if (currentMembers.any((m) => m.userId == _selectedUser!.id)) {
      setState(() {
        _loading = false;
        _error = 'این کاربر قبلاً عضو این گروه است';
      });
      return;
    }

    final result = await provider.addMember(
      widget.groupId,
      _selectedUser!.id,
      _role,
      _selectedUser!.username,
    );

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

    if (result != null) {
      Navigator.of(context).pop();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content:
              Text('«${_selectedUser!.username}» به گروه اضافه شد'),
          backgroundColor: AppTheme.success,
        ),
      );
    } else {
      setState(() => _error = provider.error);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Consumer<UserProvider>(builder: (_, userProvider, __) {
      final users = userProvider.users;

      return AlertDialog(
        title: const Row(
          children: [
            Icon(Icons.person_add_rounded, color: AppTheme.primary),
            SizedBox(width: 10),
            Text('افزودن عضو به گروه'),
          ],
        ),
        content: SizedBox(
          width: 400,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              // User selector
              DropdownButtonFormField<UserModel>(
                initialValue: _selectedUser,
                decoration: const InputDecoration(
                  labelText: 'انتخاب کاربر',
                  prefixIcon: Icon(Icons.person_outline_rounded),
                ),
                hint: const Text('کاربر را انتخاب کنید'),
                items: users
                    .map((u) => DropdownMenuItem(
                          value: u,
                          child: Text(
                            '${u.username} (${u.role.label})',
                          ),
                        ))
                    .toList(),
                onChanged: (v) => setState(() => _selectedUser = v),
              ),
              const SizedBox(height: 16),

              // Role selector
              DropdownButtonFormField<GroupRole>(
                initialValue: _role,
                decoration: const InputDecoration(
                  labelText: 'نقش در گروه',
                  prefixIcon: Icon(Icons.badge_outlined),
                ),
                items: GroupRole.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('افزودن'),
          ),
        ],
      );
    });
  }
}

// ── Members Table ────────────────────────────────────────────────────────────

class _MembersTable extends StatelessWidget {
  final String groupId;
  const _MembersTable({required this.groupId});

  @override
  Widget build(BuildContext context) {
    return Consumer<GroupProvider>(builder: (_, provider, __) {
      final members = provider.membersOf(groupId);

      if (members.isEmpty) {
        return Card(
          child: Padding(
            padding: const EdgeInsets.all(40),
            child: Center(
              child: Column(
                children: [
                  const Icon(Icons.people_outline_rounded,
                      size: 56, color: AppTheme.border),
                  const SizedBox(height: 12),
                  const Text(
                    'هنوز عضوی به این گروه اضافه نشده است',
                    style: TextStyle(color: AppTheme.textSecondary),
                  ),
                  const SizedBox(height: 16),
                  ElevatedButton.icon(
                    onPressed: () => showDialog(
                      context: context,
                      builder: (_) => _AddMemberDialog(groupId: groupId),
                    ),
                    icon: const Icon(Icons.person_add_rounded, size: 16),
                    label: const Text('افزودن اولین عضو'),
                  ),
                ],
              ),
            ),
          ),
        );
      }

      return Card(
        child: ClipRRect(
          borderRadius: BorderRadius.circular(12),
          child: SingleChildScrollView(
            child: SingleChildScrollView(
              scrollDirection: Axis.horizontal,
              child: DataTable(
                columns: const [
                  DataColumn(label: Text('کاربر')),
                  DataColumn(label: Text('نقش در گروه')),
                  DataColumn(label: Text('تاریخ عضویت')),
                ],
                rows: members.map((m) => _buildRow(m)).toList(),
              ),
            ),
          ),
        ),
      );
    });
  }

  DataRow _buildRow(GroupMemberModel member) {
    final color = member.role == GroupRole.manager
        ? const Color(0xFF0891B2)
        : AppTheme.textSecondary;

    return DataRow(
      cells: [
        DataCell(
          Row(
            mainAxisSize: MainAxisSize.min,
            children: [
              CircleAvatar(
                radius: 16,
                backgroundColor: AppTheme.primary.withValues(alpha: 0.12),
                child: Text(
                  (member.username ?? member.userId)[0].toUpperCase(),
                  style: const TextStyle(
                    color: AppTheme.primary,
                    fontSize: 13,
                    fontWeight: FontWeight.w700,
                  ),
                ),
              ),
              const SizedBox(width: 10),
              Text(
                member.username ?? member.userId,
                style: const TextStyle(fontWeight: FontWeight.w600),
              ),
            ],
          ),
        ),
        DataCell(
          Container(
            padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
            decoration: BoxDecoration(
              color: color.withValues(alpha: 0.12),
              borderRadius: BorderRadius.circular(20),
            ),
            child: Text(
              member.role.label,
              style: TextStyle(
                color: color,
                fontSize: 12,
                fontWeight: FontWeight.w600,
              ),
            ),
          ),
        ),
        DataCell(
          Text(
            member.joinedAt != null
                ? DateFormat('yyyy/MM/dd').format(member.joinedAt!)
                : '—',
            style: const TextStyle(color: AppTheme.textSecondary),
          ),
        ),
      ],
    );
  }
}

// ── Status Badge ─────────────────────────────────────────────────────────────

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: Text(
        isActive ? 'فعال' : 'غیرفعال',
        style: TextStyle(
          color: color,
          fontSize: 12,
          fontWeight: FontWeight.w600,
        ),
      ),
    );
  }
}