Holzleitner-Lieferservice-App/lib/feature/delivery/detail/presentation/delivery_sign.dart

import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:signature/signature.dart';

import 'package:hl_lieferservice/domain/entity/delivery.dart';
import 'package:hl_lieferservice/domain/entity/delivery_note.dart';
import 'package:hl_lieferservice/domain/entity/tour_details.dart';

/// Daten, die der Abschluss-Flow an den Aufrufer zurückgibt: beide
/// Unterschriften als PNG plus die dokumentierten Bestätigungen des Kunden.
class SignatureResult {
  const SignatureResult({
    required this.customerSignaturePng,
    required this.driverSignaturePng,
    required this.receiptConfirmed,
    required this.notesAcknowledged,
    required this.acknowledgedNoteIds,
  });

  final Uint8List customerSignaturePng;
  final Uint8List driverSignaturePng;
  final bool receiptConfirmed;
  final bool notesAcknowledged;
  final List<String> acknowledgedNoteIds;
}

/// Mehrstufiger Unterschrift-Flow zum Abschließen einer Lieferung.
///
/// Das Kassieren passiert vorher im eigenen Workflow-Step „Zahlung" und
/// wird dort protokolliert — dieser Flow enthält nur noch die Unterschriften.
///
/// Stufe 1 (Kunde): sieht die Anmerkungen zur Lieferung, hakt zwei
/// Bestätigungen ab (Anmerkungen-Kenntnisnahme — nur Pflicht, wenn Notizen
/// vorhanden; Empfangsbestätigung — immer Pflicht) und unterschreibt.
/// Stufe 2 (Fahrer): unterschreibt.
///
/// Erst nach beiden Unterschriften ruft die View [onSigned] mit dem
/// vollständigen [SignatureResult] auf — der Aufrufer triggert dann den
/// Backend-Abschluss und schließt die Seite.
class SignatureView extends StatefulWidget {
  const SignatureView({
    super.key,
    required this.delivery,
    required this.details,
    required this.onSigned,
  });

  final Delivery delivery;
  final TourDetails details;
  final void Function(SignatureResult result) onSigned;

  @override
  State<SignatureView> createState() => _SignatureViewState();
}

/// Stufen des Abschluss-Flows.
enum _SignStage { customer, driver }

class _SignatureViewState extends State<SignatureView> {
  static const String _receiptText =
      'Ich bestätige, dass ich die Ware im ordnungsgemäßen Zustand erhalten '
      'habe und, dass die Aufstell- und Einbauarbeiten korrekt durchgeführt '
      'wurden.';
  static const String _notesText =
      'Ich nehme die oben genannten Anmerkungen zur Lieferung zur Kenntnis.';

  final SignatureController _customerController = SignatureController(
    penStrokeWidth: 3,
    penColor: Colors.black,
    exportBackgroundColor: Colors.white,
  );
  final SignatureController _driverController = SignatureController(
    penStrokeWidth: 3,
    penColor: Colors.black,
    exportBackgroundColor: Colors.white,
  );

  late final List<DeliveryNote> _notes;
  _SignStage _stage = _SignStage.customer;
  bool _receiptAccepted = false;
  bool _notesAccepted = false;
  bool _customerEmpty = true;
  bool _driverEmpty = true;

  bool get _notesEmpty => _notes.isEmpty;

  @override
  void initState() {
    super.initState();
    _notes =
        widget.details.notesByDeliveryId[widget.delivery.id] ??
        const <DeliveryNote>[];
    _customerController.addListener(() {
      if (_customerEmpty != _customerController.isEmpty) {
        setState(() => _customerEmpty = _customerController.isEmpty);
      }
    });
    _driverController.addListener(() {
      if (_driverEmpty != _driverController.isEmpty) {
        setState(() => _driverEmpty = _driverController.isEmpty);
      }
    });
  }

  @override
  void dispose() {
    _customerController.dispose();
    _driverController.dispose();
    super.dispose();
  }

  bool get _customerStepValid =>
      _receiptAccepted && (_notesAccepted || _notesEmpty) && !_customerEmpty;

  /// Ist der Primär-Button auf der aktuellen Stufe aktiv?
  bool get _stageValid {
    switch (_stage) {
      case _SignStage.customer:
        return _customerStepValid;
      case _SignStage.driver:
        return !_driverEmpty;
    }
  }

  Future<void> _onPrimaryPressed() async {
    switch (_stage) {
      case _SignStage.customer:
        setState(() => _stage = _SignStage.driver);
        return;
      case _SignStage.driver:
        final customerPng = await _customerController.toPngBytes();
        final driverPng = await _driverController.toPngBytes();
        if (customerPng == null || driverPng == null) return;
        widget.onSigned(
          SignatureResult(
            customerSignaturePng: customerPng,
            driverSignaturePng: driverPng,
            receiptConfirmed: _receiptAccepted,
            notesAcknowledged: _notesEmpty ? false : _notesAccepted,
            acknowledgedNoteIds:
                _notesEmpty ? const [] : _notes.map((n) => n.id).toList(),
          ),
        );
    }
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final customer = widget.details.customerOf(widget.delivery);
    final date = DateFormat('dd.MM.yyyy').format(DateTime.now());
    final isDriver = _stage == _SignStage.driver;

    final String title;
    switch (_stage) {
      case _SignStage.customer:
        title = 'Unterschrift des Kunden';
      case _SignStage.driver:
        title = 'Unterschrift des Fahrers';
    }

    return Scaffold(
      appBar: AppBar(title: Text(title)),
      body: SafeArea(
        child: ListView(
          padding: const EdgeInsets.all(16),
          children: [
            if (!isDriver) ...[
              _NotesSection(notes: _notes),
              const SizedBox(height: 16),
              _ConfirmTile(
                value: _notesAccepted,
                enabled: !_notesEmpty,
                label: _notesText,
                onChanged: (v) => setState(() => _notesAccepted = v),
              ),
              _ConfirmTile(
                value: _receiptAccepted,
                enabled: true,
                label: _receiptText,
                onChanged: (v) => setState(() => _receiptAccepted = v),
              ),
              const SizedBox(height: 16),
            ],
            Text(
              'Lieferung an: ${customer?.name ?? '⟨Unbekannter Kunde⟩'}',
              style: theme.textTheme.titleSmall?.copyWith(
                fontWeight: FontWeight.w700,
              ),
            ),
            const SizedBox(height: 8),
            _SignaturePad(
              controller: isDriver ? _driverController : _customerController,
              onClear:
                  () =>
                      (isDriver ? _driverController : _customerController)
                          .clear(),
            ),
            const SizedBox(height: 4),
            Text(
              '${customer?.address.city ?? ''}, den $date',
              style: theme.textTheme.bodySmall,
            ),
            const SizedBox(height: 24),
            FilledButton.icon(
              onPressed: _stageValid ? _onPrimaryPressed : null,
              icon: Icon(isDriver ? Icons.check : Icons.arrow_forward),
              label: Text(isDriver ? 'Abschließen' : 'Weiter'),
            ),
          ],
        ),
      ),
    );
  }
}

// ─── Notizen-Block ────────────────────────────────────────────────────────

class _NotesSection extends StatelessWidget {
  const _NotesSection({required this.notes});

  final List<DeliveryNote> notes;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(
          'Anmerkungen zur Lieferung',
          style: theme.textTheme.titleMedium?.copyWith(
            fontWeight: FontWeight.w700,
          ),
        ),
        const SizedBox(height: 8),
        if (notes.isEmpty)
          Card(
            margin: EdgeInsets.zero,
            child: Padding(
              padding: const EdgeInsets.all(16),
              child: Text(
                'Keine Anmerkungen vorhanden.',
                style: TextStyle(
                  fontStyle: FontStyle.italic,
                  color: theme.colorScheme.onSurfaceVariant,
                ),
              ),
            ),
          )
        else
          Card(
            margin: EdgeInsets.zero,
            child: Column(
              children: [
                for (int i = 0; i < notes.length; i++) ...[
                  ListTile(
                    leading: Icon(
                      notes[i].imageAttachment != null
                          ? (notes[i].imageAttachmentDeleted
                              ? Icons.picture_as_pdf_outlined
                              : Icons.photo_outlined)
                          : Icons.event_note_outlined,
                      color: theme.colorScheme.primary,
                    ),
                    title: Text(
                      notes[i].text?.trim().isNotEmpty == true
                          ? notes[i].text!.trim()
                          : (notes[i].imageAttachmentDeleted
                              ? 'Bild im Lieferbericht enthalten'
                              : 'Foto-Anhang'),
                    ),
                  ),
                  if (i < notes.length - 1)
                    const Divider(height: 1, indent: 16, endIndent: 16),
                ],
              ],
            ),
          ),
      ],
    );
  }
}

// ─── Bestätigungs-Checkbox ──────────────────────────────────────────────────

class _ConfirmTile extends StatelessWidget {
  const _ConfirmTile({
    required this.value,
    required this.enabled,
    required this.label,
    required this.onChanged,
  });

  final bool value;
  final bool enabled;
  final String label;
  final ValueChanged<bool> onChanged;

  @override
  Widget build(BuildContext context) {
    return CheckboxListTile(
      value: value,
      onChanged: enabled ? (v) => onChanged(v ?? false) : null,
      controlAffinity: ListTileControlAffinity.leading,
      contentPadding: EdgeInsets.zero,
      title: Text(label, style: const TextStyle(fontSize: 14)),
    );
  }
}

// ─── Signatur-Pad ───────────────────────────────────────────────────────────

class _SignaturePad extends StatelessWidget {
  const _SignaturePad({required this.controller, required this.onClear});

  final SignatureController controller;
  final VoidCallback onClear;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        Container(
          height: 220,
          decoration: BoxDecoration(
            color: Colors.white,
            border: Border.all(color: theme.colorScheme.outline),
            borderRadius: BorderRadius.circular(8),
          ),
          clipBehavior: Clip.antiAlias,
          child: Signature(
            controller: controller,
            backgroundColor: Colors.white,
          ),
        ),
        Align(
          alignment: Alignment.centerRight,
          child: TextButton.icon(
            onPressed: onClear,
            icon: const Icon(Icons.undo),
            label: const Text('Löschen'),
          ),
        ),
      ],
    );
  }
}