import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../core/api_client.dart';
import '../core/api_service.dart';
import '../models/automation_rule.dart';
import '../models/device.dart';
import '../models/device_type.dart';
import '../models/zone.dart';

const _operators = ['>', '<', '>=', '<=', '=', '!='];

/// Create/edit automation rule form. Pass an existing [rule] to edit it in
/// place; omit it to create a new one. Pops with `true` on success.
///
/// Dropdown options (sensor/actuator devices, sensor types, action types)
/// are all derived from the backend's device/device-type data, never
/// hardcoded — a new device_type with new capabilities shows up here
/// automatically, per the platform's "don't hardcode the domain" rule.
class AutomationRuleFormScreen extends StatefulWidget {
  const AutomationRuleFormScreen({super.key, this.rule});

  final AutomationRule? rule;

  bool get isEditing => rule != null;

  @override
  State<AutomationRuleFormScreen> createState() => _AutomationRuleFormScreenState();
}

class _AutomationRuleFormScreenState extends State<AutomationRuleFormScreen> {
  final _formKey = GlobalKey<FormState>();
  late final _conditionValueController =
      TextEditingController(text: widget.rule?.conditionValue.toString());
  late final _levelController = TextEditingController(text: widget.rule?.level?.toString());

  late Future<(List<Zone>, List<Device>, List<DeviceType>)> _optionsFuture;

  int? _zoneId;
  int? _targetDeviceId;
  int? _conditionSourceDeviceId;
  String? _conditionSensorType;
  late String _conditionOperator;
  String? _actionType;
  late bool _isActive;

  bool _isSubmitting = false;
  Map<String, List<String>> _fieldErrors = {};

  @override
  void initState() {
    super.initState();
    _zoneId = widget.rule?.zone?.id;
    _targetDeviceId = widget.rule?.targetDevice?.id;
    _conditionSourceDeviceId = widget.rule?.conditionSourceDevice?.id;
    _conditionSensorType = widget.rule?.conditionSensorType;
    _conditionOperator = widget.rule?.conditionOperator ?? _operators.first;
    _actionType = widget.rule?.actionType;
    _isActive = widget.rule?.isActive ?? true;

    final apiService = context.read<ApiService>();
    _optionsFuture = (apiService.zones(), apiService.devices(), apiService.deviceTypes()).wait;
  }

  @override
  void dispose() {
    _conditionValueController.dispose();
    _levelController.dispose();
    super.dispose();
  }

  Future<void> _submit() async {
    if (!_formKey.currentState!.validate()) return;

    final missing = <String, List<String>>{
      if (_zoneId == null) 'zone_id': ['Выберите зону'],
      if (_targetDeviceId == null) 'target_device_id': ['Выберите целевое устройство'],
      if (_conditionSourceDeviceId == null) 'condition_source_device_id': ['Выберите датчик'],
      if (_conditionSensorType == null) 'condition_sensor_type': ['Выберите тип показания'],
      if (_actionType == null) 'action_type': ['Выберите действие'],
    };
    if (missing.isNotEmpty) {
      setState(() => _fieldErrors = missing);
      return;
    }

    setState(() {
      _isSubmitting = true;
      _fieldErrors = {};
    });

    final payload = <String, dynamic>{
      'zone_id': _zoneId,
      'target_device_id': _targetDeviceId,
      'condition_source_device_id': _conditionSourceDeviceId,
      'condition_sensor_type': _conditionSensorType,
      'condition_operator': _conditionOperator,
      'condition_value': double.parse(_conditionValueController.text),
      'action_type': _actionType,
      'is_active': _isActive,
      if (_actionType == 'set_level') 'level': double.parse(_levelController.text),
    };

    final apiService = context.read<ApiService>();

    try {
      if (widget.isEditing) {
        await apiService.updateAutomationRule(widget.rule!.id, payload);
      } else {
        await apiService.createAutomationRule(payload);
      }
      if (mounted) Navigator.of(context).pop(true);
    } on ApiException catch (e) {
      setState(() => _fieldErrors = e.errors ?? {});
      if (e.errors == null && mounted) {
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(e.message)));
      }
    } finally {
      if (mounted) setState(() => _isSubmitting = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(widget.isEditing ? 'Редактировать правило' : 'Новое правило')),
      body: FutureBuilder<(List<Zone>, List<Device>, List<DeviceType>)>(
        future: _optionsFuture,
        builder: (context, snapshot) {
          if (snapshot.connectionState != ConnectionState.done) {
            return const Center(child: CircularProgressIndicator());
          }
          if (snapshot.hasError) {
            return Center(child: Text('${snapshot.error}'));
          }

          final (zones, devices, deviceTypes) = snapshot.data!;
          final sensorDevices = devices.where((d) => d.deviceType?.isSensor ?? false).toList();
          final actuatorDevices = devices.where((d) => d.deviceType?.isActuator ?? false).toList();
          final sensorTypeOptions = deviceTypes
              .where((t) => t.isSensor)
              .expand((t) => t.capabilities)
              .toSet()
              .toList()
            ..sort();
          final actionTypeOptions = deviceTypes
              .where((t) => t.isActuator)
              .expand((t) => t.capabilities)
              .toSet()
              .toList()
            ..sort();

          return Form(
            key: _formKey,
            child: ListView(
              padding: const EdgeInsets.all(16),
              children: [
                DropdownButtonFormField<int>(
                  initialValue: _zoneId,
                  decoration: InputDecoration(labelText: 'Зона', errorText: _fieldErrors['zone_id']?.first),
                  items: zones.map((z) => DropdownMenuItem(value: z.id, child: Text(z.name))).toList(),
                  onChanged: (value) => setState(() => _zoneId = value),
                ),
                const SizedBox(height: 24),
                Text('ЕСЛИ', style: Theme.of(context).textTheme.titleSmall),
                const SizedBox(height: 8),
                DropdownButtonFormField<int>(
                  initialValue: _conditionSourceDeviceId,
                  decoration: InputDecoration(
                    labelText: 'Датчик',
                    errorText: _fieldErrors['condition_source_device_id']?.first,
                  ),
                  items: sensorDevices.map((d) => DropdownMenuItem(value: d.id, child: Text(d.name))).toList(),
                  onChanged: (value) => setState(() => _conditionSourceDeviceId = value),
                ),
                const SizedBox(height: 16),
                DropdownButtonFormField<String>(
                  initialValue: _conditionSensorType,
                  decoration: InputDecoration(
                    labelText: 'Тип показания',
                    errorText: _fieldErrors['condition_sensor_type']?.first,
                  ),
                  items: sensorTypeOptions.map((s) => DropdownMenuItem(value: s, child: Text(s))).toList(),
                  onChanged: (value) => setState(() => _conditionSensorType = value),
                ),
                const SizedBox(height: 16),
                Row(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Expanded(
                      child: DropdownButtonFormField<String>(
                        initialValue: _conditionOperator,
                        decoration: const InputDecoration(labelText: 'Оператор'),
                        items: _operators.map((op) => DropdownMenuItem(value: op, child: Text(op))).toList(),
                        onChanged: (value) => setState(() => _conditionOperator = value!),
                      ),
                    ),
                    const SizedBox(width: 12),
                    Expanded(
                      child: TextFormField(
                        controller: _conditionValueController,
                        decoration: const InputDecoration(labelText: 'Значение'),
                        keyboardType: const TextInputType.numberWithOptions(decimal: true),
                        validator: (value) =>
                            (value == null || double.tryParse(value) == null) ? 'Введите число' : null,
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 24),
                Text('ТО', style: Theme.of(context).textTheme.titleSmall),
                const SizedBox(height: 8),
                DropdownButtonFormField<String>(
                  initialValue: _actionType,
                  decoration:
                      InputDecoration(labelText: 'Действие', errorText: _fieldErrors['action_type']?.first),
                  items: actionTypeOptions.map((a) => DropdownMenuItem(value: a, child: Text(a))).toList(),
                  onChanged: (value) => setState(() => _actionType = value),
                ),
                if (_actionType == 'set_level') ...[
                  const SizedBox(height: 16),
                  TextFormField(
                    controller: _levelController,
                    decoration: const InputDecoration(labelText: 'Уровень'),
                    keyboardType: const TextInputType.numberWithOptions(decimal: true),
                    validator: (value) => (_actionType == 'set_level' && double.tryParse(value ?? '') == null)
                        ? 'Введите число'
                        : null,
                  ),
                ],
                const SizedBox(height: 16),
                DropdownButtonFormField<int>(
                  initialValue: _targetDeviceId,
                  decoration: InputDecoration(
                    labelText: 'Целевое устройство',
                    errorText: _fieldErrors['target_device_id']?.first,
                  ),
                  items: actuatorDevices.map((d) => DropdownMenuItem(value: d.id, child: Text(d.name))).toList(),
                  onChanged: (value) => setState(() => _targetDeviceId = value),
                ),
                const SizedBox(height: 16),
                SwitchListTile(
                  contentPadding: EdgeInsets.zero,
                  title: const Text('Активно'),
                  value: _isActive,
                  onChanged: (value) => setState(() => _isActive = value),
                ),
                const SizedBox(height: 24),
                FilledButton(
                  onPressed: _isSubmitting ? null : _submit,
                  child: _isSubmitting
                      ? const SizedBox(height: 20, width: 20, child: CircularProgressIndicator(strokeWidth: 2))
                      : Text(widget.isEditing ? 'Сохранить' : 'Создать'),
                ),
              ],
            ),
          );
        },
      ),
    );
  }
}