import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:anyway/domain/entities/preferences.dart';
import 'package:anyway/presentation/providers/trip_provider.dart';
import 'package:anyway/presentation/pages/new_trip_preferences.dart';
import 'package:anyway/presentation/pages/trip_creation_flow.dart';
import 'package:anyway/domain/entities/landmark.dart';
import 'package:anyway/presentation/providers/landmark_providers.dart';

class NewTripPage extends ConsumerStatefulWidget {
  const NewTripPage({super.key});

  @override
  ConsumerState<NewTripPage> createState() => _NewTripPageState();
}

class _NewTripPageState extends ConsumerState<NewTripPage> {
  int _currentStep = 0;

  bool _isCreating = false;
  List<double>? _selectedStartLocation;

  bool get _hasSelectedLocation => _selectedStartLocation != null;

  Future<void> _pickLocation() async {
    final result = await Navigator.of(context).push<List<double>>(
      MaterialPageRoute(
        builder: (_) =>
            const TripLocationSelectionPage(autoNavigateToPreferences: false),
      ),
    );

    if (!mounted) return;
    if (result != null) {
      setState(() => _selectedStartLocation = result);
    }
  }

  void _openPreferencesPage() {
    if (!_hasSelectedLocation) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Select a start location first.')),
      );
      return;
    }

    Navigator.of(context).push(
      MaterialPageRoute(
        builder: (_) =>
            NewTripPreferencesPage(startLocation: _selectedStartLocation!),
      ),
    );
  }

  void _showSelectLocationReminder() {
    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(content: Text('Choose a start location to continue.')),
    );
  }

  Widget _buildIntermediateLandmarks(List<Landmark> landmarks) {
    return Card(
      margin: EdgeInsets.zero,
      child: Padding(
        padding: const EdgeInsets.all(12.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text(
              'Fetched landmarks',
              style: TextStyle(fontWeight: FontWeight.bold),
            ),
            if (landmarks.isEmpty)
              const Padding(
                padding: EdgeInsets.only(top: 8.0),
                child: Text(
                  'No landmarks fetched yet. Create a trip to load candidates.',
                ),
              )
            else
              SizedBox(
                height: 160,
                child: ListView.separated(
                  itemCount: landmarks.length,
                  itemBuilder: (context, index) {
                    final lm = landmarks[index];
                    final coords = lm.location;
                    final subtitle = coords.length >= 2
                        ? 'Lat ${coords[0].toStringAsFixed(4)}, Lon ${coords[1].toStringAsFixed(4)}'
                        : 'Coordinates unavailable';
                    return ListTile(
                      leading: const Icon(Icons.place),
                      title: Text(lm.name),
                      subtitle: Text(subtitle),
                    );
                  },
                  separatorBuilder: (context, index) =>
                      const Divider(height: 0),
                ),
              ),
          ],
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final intermediateLandmarks = ref.watch(intermediateLandmarksProvider);
    return Scaffold(
      appBar: AppBar(
        title: const Text('Create New Trip'),
        actions: [
          IconButton(
            tooltip: 'Preferences',
            icon: const Icon(Icons.tune),
            onPressed: _openPreferencesPage,
          ),
        ],
      ),
      body: Column(
        children: [
          Expanded(
            child: Stepper(
              currentStep: _currentStep,
              onStepContinue: () async {
                if (_currentStep == 0) {
                  if (!_hasSelectedLocation) {
                    _showSelectLocationReminder();
                    return;
                  }
                  setState(() => _currentStep = 1);
                  return;
                }

                // final step: create trip with current preferences
                if (_isCreating) return;
                setState(() => _isCreating = true);

                if (!_hasSelectedLocation) {
                  _showSelectLocationReminder();
                  setState(() {
                    _isCreating = false;
                    _currentStep = 0;
                  });
                  return;
                }

                // For now use a minimal Preferences object; UI should supply real values later.
                final prefs = Preferences(
                  scores: {'sightseeing': 3, 'shopping': 1, 'nature': 2},
                  maxTimeMinutes: 120,
                  startLocation: _selectedStartLocation!,
                );
                final createTrip = ref.read(createTripProvider);
                final messenger = ScaffoldMessenger.of(context);
                final navigator = Navigator.of(context);
                try {
                  final trip = await createTrip(prefs);
                  // Show success and (later) navigate to trip viewer
                  messenger.showSnackBar(
                    SnackBar(content: Text('Trip created: ${trip.uuid}')),
                  );
                  navigator.pop();
                } catch (e) {
                  messenger.showSnackBar(
                    SnackBar(content: Text('Failed to create trip: $e')),
                  );
                } finally {
                  if (mounted) {
                    setState(() => _isCreating = false);
                  }
                }
              },
              onStepCancel: () {
                if (_currentStep > 0) {
                  setState(() {
                    _currentStep -= 1;
                  });
                }
              },
              steps: [
                Step(
                  title: const Text('Select Location'),
                  state: _hasSelectedLocation
                      ? StepState.complete
                      : StepState.indexed,
                  content: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(
                        _hasSelectedLocation
                            ? 'Selected: ${_selectedStartLocation![0].toStringAsFixed(4)}, ${_selectedStartLocation![1].toStringAsFixed(4)}'
                            : 'Pick the starting point for your trip.',
                      ),
                      const SizedBox(height: 12),
                      SizedBox(
                        width: double.infinity,
                        child: OutlinedButton.icon(
                          icon: const Icon(Icons.map),
                          label: Text(
                            _hasSelectedLocation
                                ? 'Change location'
                                : 'Pick on map',
                          ),
                          onPressed: _pickLocation,
                        ),
                      ),
                    ],
                  ),
                  isActive: _currentStep >= 0,
                ),
                Step(
                  title: const Text('Choose Options'),
                  content: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: const [
                      SizedBox(
                        height: 200,
                        child: Center(child: Text('Options placeholder')),
                      ),
                      SizedBox(height: 8),
                      Text('Tap the tuner icon to fine-tune preferences.'),
                    ],
                  ),
                  isActive: _currentStep >= 1,
                ),
              ],
            ),
          ),
          const SizedBox(height: 12),
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16.0),
            child: _buildIntermediateLandmarks(intermediateLandmarks),
          ),
          const SizedBox(height: 16),
        ],
      ),
    );
  }
}