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

import 'package:hl_lieferservice/domain/entity/delivery.dart';
import 'package:hl_lieferservice/domain/entity/tour_details.dart';
import 'package:hl_lieferservice/feature/car_selection/bloc/bloc.dart';
import 'package:hl_lieferservice/feature/car_selection/bloc/state.dart';
import 'package:hl_lieferservice/feature/delivery/bloc/tour_bloc.dart';
import 'package:hl_lieferservice/feature/delivery/bloc/tour_event.dart';
import 'package:hl_lieferservice/feature/delivery/detail/model/delivery_payment_status.dart';
import 'package:hl_lieferservice/feature/delivery/detail/presentation/widget/delivered_items_card.dart';
import 'package:hl_lieferservice/feature/delivery/detail/presentation/widget/payment_breakdown_card.dart';
import 'package:hl_lieferservice/feature/delivery/detail/presentation/widget/payment_record_card.dart';
import 'package:hl_lieferservice/feature/delivery/detail/presentation/widget/payment_sheet.dart';

/// Step „Zahlung" — Zahlungsabwicklung („Abkassieren") vor der Übersicht.
///
/// Zeigt die ausgelieferten Artikel mit Menge und Preis, die Betrags-
/// aufstellung und den Zahlungsstatus. Über „Zahlung abwickeln" öffnet sich
/// das Zahlungs-Modal; die Bestätigung wird am Server protokolliert.
///
/// Ist nichts offen (bereits bezahlt), kann der Fahrer den Step
/// überspringen. Sonst gibt die Detail-Page „Weiter" erst frei, wenn eine
/// gültige Zahlung protokolliert ist (siehe `DeliveryPaymentStatus`).
class StepPayment extends StatelessWidget {
  const StepPayment({super.key, required this.delivery, required this.details});

  final Delivery delivery;
  final TourDetails details;

  @override
  Widget build(BuildContext context) {
    final status = DeliveryPaymentStatus.of(delivery, details);
    final canCollect =
        delivery.state == DeliveryState.active && status.hasOpenAmount;

    return Column(
      children: [
        Expanded(
          child: ListView(
            padding: const EdgeInsets.fromLTRB(16, 16, 16, 24),
            children: [
              const _SectionHeader(text: 'Ausgelieferte Artikel'),
              const SizedBox(height: 8),
              DeliveredItemsCard(delivery: delivery, details: details),
              const SizedBox(height: 24),
              const _SectionHeader(text: 'Betrag'),
              const SizedBox(height: 8),
              PaymentBreakdownCard(
                status: status,
                credit: details.creditOf(delivery.id),
              ),
              const SizedBox(height: 16),
              PaymentRecordCard(status: status),
            ],
          ),
        ),
        if (canCollect)
          _CollectPanel(
            status: status,
            onCollect: () => _openPaymentSheet(context, status),
          ),
      ],
    );
  }

  Future<void> _openPaymentSheet(
    BuildContext context,
    DeliveryPaymentStatus status,
  ) async {
    final tourBloc = context.read<TourBloc>();
    final actorCarId = _actorCarId(context);
    final customer = details.customerOf(delivery);

    final result = await showPaymentSheet(
      context,
      openCents: status.openCents,
      customerNumber: customer?.erpCustomerId ?? 0,
      // Vorauswahl: zuletzt abgewickelte Methode, sonst die vom Beleg.
      preselectedMethodId:
          status.latestPayment?.paymentMethodId ?? delivery.paymentMethodId,
    );

    switch (result) {
      case PaymentConfirmed(:final method):
        tourBloc.add(
          RecordDeliveryPayment(
            deliveryId: delivery.id,
            paymentMethodId: method.id,
            expectedAmountCents: status.openCents,
            actorCarId: actorCarId,
          ),
        );
      case DeliveryCancelRequested(:final reason):
        tourBloc.add(CancelDelivery(deliveryId: delivery.id, reason: reason));
      case null:
        break;
    }
  }

  String? _actorCarId(BuildContext context) {
    final state = context.read<CarSelectBloc>().state;
    return state is CarSelectComplete ? state.selectedCar.id : null;
  }
}

/// Fester Bereich unten: offener Betrag + großer „Zahlung abwickeln"-Button.
/// Bleibt sichtbar, auch wenn die Artikelliste lang ist.
class _CollectPanel extends StatelessWidget {
  const _CollectPanel({required this.status, required this.onCollect});

  final DeliveryPaymentStatus status;
  final VoidCallback onCollect;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final settled = status.validPayment != null;
    return Material(
      elevation: 6,
      color: theme.colorScheme.surface,
      child: Padding(
        padding: const EdgeInsets.fromLTRB(16, 12, 16, 12),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            Row(
              children: [
                Text('Offener Betrag', style: theme.textTheme.titleMedium),
                const Spacer(),
                Text(
                  formatEuroCents(status.openCents),
                  style: theme.textTheme.headlineSmall?.copyWith(
                    fontWeight: FontWeight.w800,
                    color: theme.colorScheme.primary,
                  ),
                ),
              ],
            ),
            const SizedBox(height: 10),
            if (settled)
              // Bereits abgewickelt: Korrektur möglich, aber nicht mehr im
              // Vordergrund — „Weiter" ist jetzt der nächste Schritt.
              OutlinedButton.icon(
                style: OutlinedButton.styleFrom(
                  minimumSize: const Size.fromHeight(52),
                ),
                onPressed: onCollect,
                icon: const Icon(Icons.edit_outlined),
                label: const Text('Zahlung korrigieren'),
              )
            else
              FilledButton.icon(
                style: FilledButton.styleFrom(
                  minimumSize: const Size.fromHeight(68),
                  textStyle: const TextStyle(
                    fontSize: 20,
                    fontWeight: FontWeight.w700,
                  ),
                ),
                onPressed: onCollect,
                icon: const Icon(Icons.point_of_sale, size: 28),
                label: const Text('Zahlung abwickeln'),
              ),
          ],
        ),
      ),
    );
  }
}

class _SectionHeader extends StatelessWidget {
  const _SectionHeader({required this.text});
  final String text;

  @override
  Widget build(BuildContext context) {
    return Text(
      text,
      style: Theme.of(
        context,
      ).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w700),
    );
  }
}