import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:reactive_mind_map/reactive_mind_map.dart' as rm;
import 'package:uuid/uuid.dart';
import '../models/mindmap_model.dart';
import '../providers/mind_maps_provider.dart';
import '../core/admin_access_service.dart';
import '../core/deepseek_service.dart';

class MindMapInteractiveScreen extends ConsumerStatefulWidget {
  final MindMapModel mindMap;

  const MindMapInteractiveScreen({super.key, required this.mindMap});

  @override
  ConsumerState<MindMapInteractiveScreen> createState() =>
      _MindMapInteractiveScreenState();
}

class _MindMapInteractiveScreenState
    extends ConsumerState<MindMapInteractiveScreen> {
  late List<Map<String, dynamic>> _nodes;
  late bool _isMain;
  bool _isEditing = false;
  bool _showChat = false;
  bool _isAISubmitting = false;
  final TextEditingController _chatController = TextEditingController();
  final List<ChatMessage> _chatMessages = [];

  @override
  void initState() {
    super.initState();
    _nodes = widget.mindMap.nodes.toList();
    _isMain = widget.mindMap.isMain;
  }

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

  // ========== CHAT FUNCTIONS ==========

  void _addChatMessage(String text, bool isUser, {AIAction? action}) {
    setState(() {
      _chatMessages.add(ChatMessage(
        text: text,
        isUser: isUser,
        timestamp: DateTime.now(),
        action: action,
      ));
    });
  }

  Future<void> _sendToAI(String message) async {
    if (message.trim().isEmpty) return;

    _addChatMessage(message, true);
    _chatController.clear();
    setState(() => _isAISubmitting = true);

    try {
      // Отправляем запрос к DeepSeek
      final response = await deepSeekService.chatCompletion(
        messages: [
          ..._chatMessages
              .where((m) => m.isUser || m.text.startsWith('AI:'))
              .map((m) => {
                    'role': m.isUser ? 'user' : 'assistant',
                    'content': m.text,
                  })
              .toList(),
          {
            'role': 'system',
            'content': '''
Ты AI ассистент для работы с mind maps.
Текущая структура mind map "${widget.mindMap.title}":
${_nodes.map((n) => '${"  " * (n["level"] ?? 0)}- ${n["title"]} (уровень ${n["level"] ?? 0})').join('\n')}

Когда пользователь просит что-то сделать с mind map, отвечай в формате:
ACTION: <add|edit|delete|suggest>
TARGET: <id узла или null>
CHANGES: [
  {"action": "add", "title": "...", "level": 0, "parentId": null},
  {"action": "edit", "id": "...", "title": "..."},
  {"action": "delete", "id": "..."}
]
EXPLANATION: <объяснение на русском>

Или просто отвечай текстом если действие не требуется.
''',
          },
        ],
      );

      // Парсим ответ AI
      if (response.containsKey('ACTION')) {
        final action = response['ACTION'] as String;
        final changes = response['CHANGES'] as List<dynamic>;
        final explanation = response['EXPLANATION'] as String? ?? '';

        _addChatMessage(
          'AI: $explanation',
          false,
          action: AIAction(
            type: action,
            changes: changes.map((c) => c as Map<String, dynamic>).toList(),
            isApplied: false,
          ),
        );
      } else {
        _addChatMessage('AI: $response', false);
      }
    } catch (e) {
      _addChatMessage('❌ Ошибка AI: $e', false);
    } finally {
      setState(() => _isAISubmitting = false);
    }
  }

  void _applyAIChanges(AIAction action) {
    for (final change in action.changes) {
      final actionType = change['action'] as String;

      switch (actionType) {
        case 'add':
          _nodes.add({
            'id': const Uuid().v4(),
            'title': change['title'] ?? '',
            'level': change['level'] ?? 0,
            'parentId': change['parentId'],
            'color': _getColorForLevel(change['level'] ?? 0),
          });
          break;

        case 'edit':
          final index = _nodes.indexWhere((n) => n['id'] == change['id']);
          if (index != -1) {
            _nodes[index] = {
              ..._nodes[index],
              'title': change['title'] ?? _nodes[index]['title'],
            };
          }
          break;

        case 'delete':
          final nodesToDelete = <String>{change['id'] as String};
          _collectChildren(change['id'] as String, nodesToDelete);
          _nodes.removeWhere((n) => nodesToDelete.contains(n['id']));
          break;
      }
    }

    // Обновляем сообщение в чате
    final msgIndex = _chatMessages.indexWhere((m) => m.action == action);
    if (msgIndex != -1) {
      setState(() {
        _chatMessages[msgIndex] = _chatMessages[msgIndex].copyWith(
          action: action.copyWith(isApplied: true),
        );
        _nodes = _nodes.toList(); // Триггер rebuild
      });
    }

    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(
        content: Text('✅ Изменения AI применены'),
        backgroundColor: Colors.green,
      ),
    );
  }

  void _rejectAIChanges(AIAction action) {
    final msgIndex = _chatMessages.indexWhere((m) => m.action == action);
    if (msgIndex != -1) {
      setState(() {
        _chatMessages[msgIndex] = _chatMessages[msgIndex].copyWith(
          action: action.copyWith(isApplied: false),
        );
      });
    }
  }

  // ========== EDIT FUNCTIONS ==========

  void _addNode({String? parentId}) {
    showDialog(
      context: context,
      builder: (context) => _NodeTitleDialog(
        onAdd: (title) {
          final parentNode = parentId != null
              ? _nodes.firstWhere((n) => n['id'] == parentId, orElse: () => {})
              : null;

          setState(() {
            _nodes.add({
              'id': const Uuid().v4(),
              'title': title,
              'level': parentNode != null ? (parentNode['level'] ?? 0) + 1 : 0,
              'parentId': parentId,
              'color': _getColorForLevel(
                  parentNode != null ? (parentNode['level'] ?? 0) + 1 : 0),
            });
          });
        },
      ),
    );
  }

  void _editNode(String nodeId) {
    final node = _nodes.firstWhere((n) => n['id'] == nodeId);
    final controller = TextEditingController(text: node['title'] as String);

    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Редактировать узел'),
        content: TextField(
          controller: controller,
          autofocus: true,
          decoration: const InputDecoration(
            labelText: 'Название',
            border: OutlineInputBorder(),
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('Отмена'),
          ),
          ElevatedButton(
            onPressed: () {
              final index = _nodes.indexWhere((n) => n['id'] == nodeId);
              if (index != -1) {
                setState(() {
                  _nodes[index] = {..._nodes[index], 'title': controller.text};
                });
              }
              Navigator.pop(context);
            },
            child: const Text('Сохранить'),
          ),
        ],
      ),
    );
  }

  void _deleteNode(String nodeId) {
    final nodesToDelete = <String>{nodeId};
    _collectChildren(nodeId, nodesToDelete);

    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Удалить узел?'),
        content: Text(
            'Удалить "${_nodes.firstWhere((n) => n['id'] == nodeId)['title']}" и все дочерние узлы?'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('Отмена'),
          ),
          TextButton(
            onPressed: () {
              setState(() {
                _nodes.removeWhere((n) => nodesToDelete.contains(n['id']));
              });
              Navigator.pop(context);
            },
            style: TextButton.styleFrom(foregroundColor: Colors.red),
            child: const Text('Удалить'),
          ),
        ],
      ),
    );
  }

  void _collectChildren(String parentId, Set<String> result) {
    final children = _nodes.where((n) => n['parentId'] == parentId).toList();
    for (final child in children) {
      final childId = child['id'] as String;
      result.add(childId);
      _collectChildren(childId, result);
    }
  }

  Future<void> _saveChanges() async {
    try {
      final notifier = ref.read(mindMapsNotifierProvider.notifier);
      final isAdmin = ref.read(isAdminProvider);
      final userEmail = FirebaseAuth.instance.currentUser?.email ?? '';

      // Проверка прав
      if (!isAdmin && widget.mindMap.ownerEmail != userEmail) {
        throw Exception('Нет прав для редактирования');
      }

      final updated = widget.mindMap.copyWith(
        nodes: _nodes,
        isMain: _isMain,
        updatedAt: DateTime.now(),
      );

      await notifier.updateMindMap(widget.mindMap.id, updated);

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('✅ Изменения сохранены'),
            backgroundColor: Colors.green,
          ),
        );
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('❌ Ошибка: $e'), backgroundColor: Colors.red),
        );
      }
    }
  }

  String _getColorForLevel(int level) {
    final colors = [
      '#2196F3',
      '#4CAF50',
      '#FF9800',
      '#E91E63',
      '#9C27B0',
      '#00BCD4'
    ];
    return colors[level % colors.length];
  }

  Color _hexToColor(String hex) {
    hex = hex.replaceAll('#', '');
    if (hex.length == 6) return Color(int.parse('FF$hex', radix: 16));
    return const Color(0xFF2196F3);
  }

  // ========== BUILD ==========

  @override
  Widget build(BuildContext context) {
    final isAdmin = ref.watch(isAdminProvider);
    final userEmail = FirebaseAuth.instance.currentUser?.email ?? '';
    final canEdit = isAdmin || widget.mindMap.ownerEmail == userEmail;

    return Scaffold(
      resizeToAvoidBottomInset: false,
      appBar: AppBar(
        title: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(widget.mindMap.title),
            Row(
              children: [
                Icon(
                  _isMain ? Icons.star : Icons.person,
                  size: 14,
                  color: _isMain ? Colors.amber : Colors.blue,
                ),
                const SizedBox(width: 4),
                Text(
                  _isMain ? 'Основная' : 'Личная',
                  style: TextStyle(
                    fontSize: 12,
                    color: _isMain ? Colors.amber : Colors.blue,
                  ),
                ),
                if (canEdit && _isEditing)
                  Padding(
                    padding: const EdgeInsets.only(left: 8),
                    child: Text(
                      '✏️ Редактирование',
                      style: const TextStyle(
                        fontSize: 12,
                        color: Colors.green,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                  ),
              ],
            ),
          ],
        ),
        actions: [
          // Toggle edit mode
          if (canEdit)
            IconButton(
              icon: Icon(_isEditing ? Icons.visibility : Icons.edit),
              onPressed: () => setState(() => _isEditing = !_isEditing),
              tooltip: _isEditing ? 'Режим просмотра' : 'Режим редактирования',
            ),
          // AI Chat
          IconButton(
            icon: Icon(_showChat ? Icons.close : Icons.auto_awesome),
            onPressed: () => setState(() => _showChat = !_showChat),
            tooltip: _showChat ? 'Закрыть AI чат' : 'Открыть AI чат',
          ),
          // Save
          if (_isEditing)
            IconButton(
              icon: const Icon(Icons.save),
              onPressed: _saveChanges,
              tooltip: 'Сохранить изменения',
            ),
        ],
      ),
      body: Stack(
        children: [
          // Mind Map (фон)
          _nodes.isEmpty
              ? _buildEmptyState()
              : rm.MindMapWidget(
                  data: _buildMindMapData(),
                  style: rm.MindMapStyle(
                    layout: rm.MindMapLayout.radial,
                    nodeShape: rm.NodeShape.roundedRectangle,
                    connectionColor: Colors.blue.shade100,
                    connectionWidth: 2.0,
                  ),
                  cameraFocus: rm.CameraFocus.fitAll,
                  onNodeTap: _isEditing ? (node) => _editNode(node.id) : null,
                  onNodeLongPress:
                      _isEditing ? (node) => _deleteNode(node.id) : null,
                ),

          // Чат поверх карты
          if (_showChat) _buildChatOverlay(),
        ],
      ),

      // FAB для добавления узлов (в режиме редактирования)
      floatingActionButton: _isEditing && !_showChat
          ? FloatingActionButton(
              onPressed: () => _addNode(),
              child: const Icon(Icons.add),
              tooltip: 'Добавить корневой узел',
            )
          : null,
    );
  }

  Widget _buildChatOverlay() {
    return Positioned(
      left: 0,
      right: 0,
      bottom: 0,
      height: MediaQuery.of(context).size.height * 0.45,
      child: Column(
        children: [
          // Градиентная полоска сверху
          Container(
            height: 4,
            decoration: const BoxDecoration(
              gradient: LinearGradient(
                colors: [Colors.purple, Colors.deepPurple],
              ),
            ),
          ),

          // Панель чата
          Expanded(
            child: Container(
              color: Theme.of(context).scaffoldBackgroundColor,
              child: Column(
                children: [
                  // Header
                  Container(
                    width: double.infinity,
                    height: 44,
                    padding: const EdgeInsets.symmetric(horizontal: 16),
                    color: Colors.purple.shade800,
                    child: Row(
                      children: [
                        const Icon(Icons.auto_awesome,
                            color: Colors.white, size: 18),
                        const SizedBox(width: 8),
                        const Text(
                          'AI Ассистент',
                          style: TextStyle(
                            color: Colors.white,
                            fontWeight: FontWeight.bold,
                            fontSize: 15,
                          ),
                        ),
                        const Spacer(),
                        Text(
                          '${_chatMessages.length}',
                          style: TextStyle(
                            color: Colors.white.withOpacity(0.7),
                            fontSize: 12,
                          ),
                        ),
                      ],
                    ),
                  ),

                  // Messages
                  Expanded(
                    child: _chatMessages.isEmpty
                        ? _buildChatEmptyState()
                        : ListView.builder(
                            padding: const EdgeInsets.all(6),
                            itemCount: _chatMessages.length,
                            itemBuilder: (context, index) {
                              return _buildChatMessage(_chatMessages[index]);
                            },
                          ),
                  ),

                  // Input
                  Container(
                    padding:
                        const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
                    color: Theme.of(context).cardColor,
                    child: SafeArea(
                      top: false,
                      child: Row(
                        crossAxisAlignment: CrossAxisAlignment.end,
                        children: [
                          Expanded(
                            child: ConstrainedBox(
                              constraints: const BoxConstraints(
                                maxHeight: 40,
                              ),
                              child: TextField(
                                controller: _chatController,
                                maxLines: null,
                                minLines: 1,
                                decoration: InputDecoration(
                                  hintText: 'AI помощь...',
                                  border: OutlineInputBorder(
                                    borderRadius: BorderRadius.circular(20),
                                  ),
                                  contentPadding: const EdgeInsets.symmetric(
                                      horizontal: 12, vertical: 2),
                                  isDense: true,
                                ),
                                onSubmitted: (text) => _sendToAI(text),
                              ),
                            ),
                          ),
                          const SizedBox(width: 4),
                          SizedBox(
                            width: 34,
                            height: 34,
                            child: Material(
                              color: Colors.purple,
                              shape: const CircleBorder(),
                              child: InkWell(
                                onTap: _isAISubmitting
                                    ? null
                                    : () => _sendToAI(_chatController.text),
                                customBorder: const CircleBorder(),
                                child: _isAISubmitting
                                    ? const SizedBox(
                                        width: 12,
                                        height: 12,
                                        child: CircularProgressIndicator(
                                          strokeWidth: 2,
                                          color: Colors.white,
                                        ),
                                      )
                                    : const Icon(Icons.send,
                                        color: Colors.white, size: 12),
                              ),
                            ),
                          ),
                        ],
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildEmptyState() {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Icon(Icons.account_tree, size: 100, color: Colors.grey[400]),
          const SizedBox(height: 24),
          Text(
            'Mind map пуста',
            style: TextStyle(fontSize: 20, color: Colors.grey[600]),
          ),
          if (_isEditing) ...[
            const SizedBox(height: 16),
            ElevatedButton.icon(
              onPressed: () => _addNode(),
              icon: const Icon(Icons.add),
              label: const Text('Добавить первый узел'),
            ),
          ],
        ],
      ),
    );
  }

  Widget _buildChatEmptyState() {
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(Icons.auto_awesome, size: 40, color: Colors.purple[300]),
            const SizedBox(height: 8),
            Text(
              'AI Ассистент',
              style: TextStyle(
                fontSize: 14,
                fontWeight: FontWeight.bold,
                color: Colors.grey[700],
              ),
            ),
            const SizedBox(height: 4),
            Text(
              'Напишите "добавь узлы" или\n"предложи улучшения"',
              textAlign: TextAlign.center,
              style: TextStyle(fontSize: 11, color: Colors.grey[600]),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildChatMessage(ChatMessage msg) {
    return Align(
      alignment: msg.isUser ? Alignment.centerRight : Alignment.centerLeft,
      child: Container(
        margin: const EdgeInsets.only(bottom: 6),
        padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 6),
        decoration: BoxDecoration(
          color: msg.isUser ? Colors.blue : Colors.grey[200],
          borderRadius: BorderRadius.circular(10),
        ),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(
              msg.isUser ? msg.text : msg.text.replaceFirst('AI: ', ''),
              style: TextStyle(
                color: msg.isUser ? Colors.white : Colors.black87,
                fontSize: 13,
              ),
            ),
            if (msg.action != null) ...[
              const SizedBox(height: 6),
              _buildAIActionButtons(msg.action!),
            ],
          ],
        ),
      ),
    );
  }

  Widget _buildAIActionButtons(AIAction action) {
    if (action.isApplied) {
      return Container(
        padding: const EdgeInsets.symmetric(vertical: 4, horizontal: 8),
        decoration: BoxDecoration(
          color: Colors.green.withOpacity(0.2),
          borderRadius: BorderRadius.circular(8),
        ),
        child: const Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(Icons.check_circle, color: Colors.green, size: 16),
            SizedBox(width: 4),
            Text('Применено', style: TextStyle(color: Colors.green)),
          ],
        ),
      );
    }

    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        TextButton.icon(
          onPressed: () => _applyAIChanges(action),
          icon: const Icon(Icons.check, size: 18),
          label: const Text('Применить'),
          style: TextButton.styleFrom(
            foregroundColor: Colors.green,
            padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 0),
          ),
        ),
        const SizedBox(width: 8),
        TextButton.icon(
          onPressed: () => _rejectAIChanges(action),
          icon: const Icon(Icons.close, size: 18),
          label: const Text('Отклонить'),
          style: TextButton.styleFrom(
            foregroundColor: Colors.red,
            padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 0),
          ),
        ),
      ],
    );
  }

  rm.MindMapData _buildMindMapData() {
    final rootNodes = _nodes.where((n) => n['parentId'] == null).toList();

    if (rootNodes.isEmpty) {
      return rm.MindMapData(
          id: 'empty', title: widget.mindMap.title, children: []);
    }

    final root = rootNodes.first;
    return rm.MindMapData(
      id: root['id'] as String,
      title: root['title'] as String,
      color: _hexToColor(root['color'] as String? ?? '#2196F3'),
      children: _buildChildren(root['id'] as String),
    );
  }

  List<rm.MindMapData> _buildChildren(String parentId) {
    final children = _nodes.where((n) => n['parentId'] == parentId).toList();
    return children.map((node) {
      return rm.MindMapData(
        id: node['id'] as String,
        title: node['title'] as String,
        color: _hexToColor(node['color'] as String? ?? '#4CAF50'),
        children: _buildChildren(node['id'] as String),
      );
    }).toList();
  }
}

// ========== MODELS ==========

class ChatMessage {
  final String text;
  final bool isUser;
  final DateTime timestamp;
  final AIAction? action;

  ChatMessage({
    required this.text,
    required this.isUser,
    required this.timestamp,
    this.action,
  });

  ChatMessage copyWith({String? text, bool? isUser, AIAction? action}) {
    return ChatMessage(
      text: text ?? this.text,
      isUser: isUser ?? this.isUser,
      timestamp: timestamp,
      action: action ?? this.action,
    );
  }
}

class AIAction {
  final String type;
  final List<Map<String, dynamic>> changes;
  final bool isApplied;

  AIAction({
    required this.type,
    required this.changes,
    this.isApplied = false,
  });

  AIAction copyWith({bool? isApplied}) {
    return AIAction(
      type: type,
      changes: changes,
      isApplied: isApplied ?? this.isApplied,
    );
  }
}

class _NodeTitleDialog extends StatefulWidget {
  final Function(String) onAdd;

  const _NodeTitleDialog({required this.onAdd});

  @override
  State<_NodeTitleDialog> createState() => _NodeTitleDialogState();
}

class _NodeTitleDialogState extends State<_NodeTitleDialog> {
  final _controller = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Text('Название узла'),
      content: TextField(
        controller: _controller,
        autofocus: true,
        decoration: const InputDecoration(
          labelText: 'Введите название',
          border: OutlineInputBorder(),
        ),
        onSubmitted: (text) {
          if (text.isNotEmpty) widget.onAdd(text);
          Navigator.pop(context);
        },
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.pop(context),
          child: const Text('Отмена'),
        ),
        ElevatedButton(
          onPressed: () {
            if (_controller.text.isNotEmpty) {
              widget.onAdd(_controller.text);
            }
            Navigator.pop(context);
          },
          child: const Text('Добавить'),
        ),
      ],
    );
  }
}