import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import 'package:intl/intl.dart';

import '../../../core/router/app_router.dart';
import '../../../core/theme/app_colors.dart';
import '../../../core/theme/machine_status_theme.dart';
import '../../booking/data/booking_repository.dart';
import '../data/machine_repository.dart';
import '../domain/machine_detail.dart';

/// Réservation de créneau pour une machine.
class MachineBookingScreen extends ConsumerStatefulWidget {
  const MachineBookingScreen({super.key, required this.machineUuid});

  final String machineUuid;

  @override
  ConsumerState<MachineBookingScreen> createState() => _MachineBookingScreenState();
}

class _MachineBookingScreenState extends ConsumerState<MachineBookingScreen> {
  DateTime _selectedDate = DateTime.now();
  TimeSlot? _selectedSlot;
  bool _isBooking = false;

  Future<void> _confirmBooking(MachineDetail detail) async {
    final slot = _selectedSlot;
    if (slot == null) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Sélectionnez un créneau horaire')),
      );
      return;
    }

    setState(() => _isBooking = true);
    try {
      await ref.read(bookingRepositoryProvider).createBooking(
            machineUuid: detail.machine.uuid,
            slotStart: slot.start,
            slotEnd: slot.end,
          );
      ref.invalidate(bookingsProvider);
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Créneau réservé avec succès'),
            backgroundColor: AppColors.success,
          ),
        );
        context.go(AppRoutes.bookings);
      }
    } on BookingException catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(e.message), backgroundColor: AppColors.error),
        );
      }
    } finally {
      if (mounted) setState(() => _isBooking = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final detailAsync = ref.watch(machineDetailProvider(widget.machineUuid));

    return Scaffold(
      backgroundColor: AppColors.background,
      appBar: AppBar(title: const Text('Réserver un créneau')),
      body: detailAsync.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (_, __) => Center(child: Text('Machine introuvable', style: Theme.of(context).textTheme.titleMedium)),
        data: (detail) {
          final machine = detail.machine;
          final availabilityAsync = ref.watch(
            machineAvailabilityProvider((uuid: machine.uuid, date: _selectedDate)),
          );

          return Column(
            children: [
              Expanded(
                child: ListView(
                  padding: const EdgeInsets.all(16),
                  children: [
                    Card(
                      child: ListTile(
                        leading: CircleAvatar(
                          backgroundColor: AppColors.primary.withValues(alpha: 0.1),
                          child: Icon(
                            MachineStatusTheme.iconForType(machine.type),
                            color: AppColors.primary,
                          ),
                        ),
                        title: Text(machine.name),
                        subtitle: Text(
                          [
                            machine.typeLabel,
                            if (detail.establishmentName != null) detail.establishmentName,
                          ].join(' · '),
                        ),
                      ),
                    ),
                    const SizedBox(height: 20),
                    Text('Choisir un jour', style: Theme.of(context).textTheme.titleMedium),
                    const SizedBox(height: 10),
                    SizedBox(
                      height: 44,
                      child: ListView.separated(
                        scrollDirection: Axis.horizontal,
                        itemCount: 6,
                        separatorBuilder: (_, __) => const SizedBox(width: 8),
                        itemBuilder: (context, index) {
                          final date = DateTime.now().add(Duration(days: index));
                          final normalized = DateTime(date.year, date.month, date.day);
                          final isSelected = normalized.year == _selectedDate.year &&
                              normalized.month == _selectedDate.month &&
                              normalized.day == _selectedDate.day;

                          return ChoiceChip(
                            label: Text(DateFormat('EEE dd/MM', 'fr_FR').format(normalized)),
                            selected: isSelected,
                            onSelected: (_) => setState(() {
                              _selectedDate = normalized;
                              _selectedSlot = null;
                            }),
                            selectedColor: AppColors.primary.withValues(alpha: 0.15),
                          );
                        },
                      ),
                    ),
                    const SizedBox(height: 20),
                    Text('Créneaux disponibles', style: Theme.of(context).textTheme.titleMedium),
                    const SizedBox(height: 4),
                    Text(
                      'Vous aurez 30 min pour démarrer après le début du créneau.',
                      style: Theme.of(context).textTheme.bodyMedium,
                    ),
                    const SizedBox(height: 12),
                    availabilityAsync.when(
                      loading: () => const Center(child: Padding(
                        padding: EdgeInsets.all(24),
                        child: CircularProgressIndicator(),
                      )),
                      error: (_, __) => const Text('Impossible de charger les créneaux.'),
                      data: (slots) {
                        if (slots.isEmpty) {
                          return Padding(
                            padding: const EdgeInsets.symmetric(vertical: 16),
                            child: Text(
                              'Aucun créneau disponible ce jour.',
                              style: Theme.of(context).textTheme.bodyMedium,
                            ),
                          );
                        }
                        return Wrap(
                          spacing: 8,
                          runSpacing: 8,
                          children: slots.map((slot) {
                            final label =
                                '${DateFormat('HH:mm').format(slot.start)} – ${DateFormat('HH:mm').format(slot.end)}';
                            final isSelected = _selectedSlot?.start == slot.start;

                            return FilterChip(
                              label: Text(label),
                              selected: isSelected,
                              onSelected: (_) => setState(() => _selectedSlot = slot),
                              selectedColor: AppColors.primary.withValues(alpha: 0.15),
                              checkmarkColor: AppColors.primary,
                            );
                          }).toList(),
                        );
                      },
                    ),
                  ],
                ),
              ),
              SafeArea(
                child: Padding(
                  padding: const EdgeInsets.fromLTRB(16, 8, 16, 16),
                  child: SizedBox(
                    width: double.infinity,
                    height: 56,
                    child: ElevatedButton.icon(
                      onPressed: _isBooking ? null : () => _confirmBooking(detail),
                      style: ElevatedButton.styleFrom(
                        backgroundColor: AppColors.primary,
                        foregroundColor: Colors.white,
                        elevation: 0,
                        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(14)),
                        textStyle: const TextStyle(fontSize: 17, fontWeight: FontWeight.w600),
                      ),
                      icon: _isBooking
                          ? const SizedBox(
                              width: 22,
                              height: 22,
                              child: CircularProgressIndicator(strokeWidth: 2, color: Colors.white),
                            )
                          : const Icon(Icons.event_available_rounded, size: 24),
                      label: Text(_isBooking ? 'Réservation…' : 'Confirmer la réservation'),
                    ),
                  ),
                ),
              ),
            ],
          );
        },
      ),
    );
  }
}