timemaster-kiosk/lib/screens/stamp_screen.dart

import 'dart:async';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import '../app_version.dart';
import '../models/kiosk_session.dart';
import '../services/kiosk_service.dart';
import 'login_screen.dart';

/// Zeigt Status + Stempel-Buttons für den eingeloggten Mitarbeiter. Session
/// lebt serverseitig nur 900s (siehe kiosk_session_service.py) – nach jeder
/// Stempel-Aktion automatisch zurück zum Login (kein Grund, eingeloggt zu
/// bleiben, DSGVO: keine sichtbaren Mitarbeiterdaten länger als nötig).
class StampScreen extends StatefulWidget {
  final KioskSession session;
  const StampScreen({super.key, required this.session});

  @override
  State<StampScreen> createState() => _StampScreenState();
}

class _StampScreenState extends State<StampScreen> {
  final _service = KioskService();
  Timer? _heartbeatTimer;
  StampStatus? _status;
  bool _loading = true;
  bool _actionInProgress = false;
  String? _error;

  @override
  void initState() {
    super.initState();
    _refresh();
    _heartbeatTimer = Timer.periodic(const Duration(seconds: 30), (_) {
      _service.heartbeat(clientVersion: kAppVersion).catchError((_) {});
    });
    _service.heartbeat(clientVersion: kAppVersion).catchError((_) {});
  }

  @override
  void dispose() {
    _heartbeatTimer?.cancel();
    super.dispose();
  }

  String _dioMessage(DioException e) {
    final detail = e.response?.data is Map ? e.response?.data['detail'] : null;
    if (detail is String) return detail;
    return 'Verbindung fehlgeschlagen.';
  }

  Future<void> _refresh() async {
    setState(() {
      _loading = true;
      _error = null;
    });
    try {
      final status = await _service.status(widget.session.sessionToken);
      if (!mounted) return;
      setState(() {
        _status = status;
        _loading = false;
      });
    } on DioException catch (e) {
      setState(() {
        _error = _dioMessage(e);
        _loading = false;
      });
    } catch (_) {
      if (mounted) {
        setState(() {
          _error = 'Unerwartete Antwort vom Server.';
          _loading = false;
        });
      }
    }
  }

  Future<void> _runAction(Future<StampResult> Function() action) async {
    // Defensiver Re-Entrancy-Guard: die Buttons sind zwar per `disabled`
    // gesperrt, aber das hängt an einem setState-Rebuild. Dieser Check kostet
    // nichts und macht Doppel-Taps unabhängig vom Rendering sicher.
    if (_actionInProgress) return;
    setState(() {
      _actionInProgress = true;
      _error = null;
    });
    try {
      final result = await action();
      if (result.warnings.isNotEmpty && mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(result.warnings.join(' · ')), backgroundColor: Colors.orange[800]),
        );
      }
      await _logoutAndReturn();
    } on DioException catch (e) {
      setState(() {
        _error = _dioMessage(e);
        _actionInProgress = false;
      });
      // Status kann sich serverseitig trotz Fehler geändert haben (z.B.
      // Konflikt durch parallelen Stempel-Vorgang) – neu laden, damit die
      // Buttons nicht einen veralteten, falschen Zustand anzeigen.
      unawaited(_refresh());
    } catch (_) {
      if (mounted) {
        setState(() {
          _error = 'Unerwartete Antwort vom Server.';
          _actionInProgress = false;
        });
      }
    }
  }

  Future<void> _logoutAndReturn() async {
    await _service.logout(widget.session.sessionToken).catchError((_) {});
    if (!mounted) return;
    Navigator.of(context).pushReplacement(
      MaterialPageRoute(builder: (_) => const LoginScreen()),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.session.userName),
        actions: [
          IconButton(icon: const Icon(Icons.logout), onPressed: _logoutAndReturn),
        ],
      ),
      body: Center(
        child: ConstrainedBox(
          constraints: const BoxConstraints(maxWidth: 480),
          child: Padding(
            padding: const EdgeInsets.all(24),
            child: _loading
                ? const CircularProgressIndicator()
                : Column(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      if (_error != null) ...[
                        Text(_error!, style: const TextStyle(color: Colors.red)),
                        const SizedBox(height: 16),
                      ],
                      _statusCard(),
                      const SizedBox(height: 32),
                      ..._actionButtons(),
                    ],
                  ),
          ),
        ),
      ),
    );
  }

  Widget _statusCard() {
    final status = _status;
    String text;
    Color color;
    if (status == null || !status.stampedIn) {
      text = 'Ausgestempelt';
      color = Colors.grey;
    } else if (status.onBreak) {
      text = 'Pause aktiv';
      color = Colors.orange;
    } else {
      text = 'Eingestempelt seit ${status.startTime?.substring(0, 5) ?? '?'}';
      color = Colors.green;
    }
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(20),
        child: Row(
          children: [
            Icon(Icons.circle, color: color, size: 16),
            const SizedBox(width: 12),
            Expanded(child: Text(text, style: Theme.of(context).textTheme.titleLarge)),
          ],
        ),
      ),
    );
  }

  List<Widget> _actionButtons() {
    final status = _status;
    final disabled = _actionInProgress;
    final token = widget.session.sessionToken;

    if (status == null || !status.stampedIn) {
      return [
        SizedBox(
          width: double.infinity,
          height: 72,
          child: FilledButton.icon(
            onPressed: disabled ? null : () => _runAction(() => _service.stampIn(token)),
            icon: const Icon(Icons.login, size: 32),
            label: const Text('Einstempeln', style: TextStyle(fontSize: 20)),
          ),
        ),
      ];
    }

    if (status.onBreak) {
      return [
        SizedBox(
          width: double.infinity,
          height: 72,
          child: FilledButton.icon(
            onPressed: disabled ? null : () => _runAction(() => _service.breakEnd(token)),
            icon: const Icon(Icons.play_arrow, size: 32),
            label: const Text('Pause beenden', style: TextStyle(fontSize: 20)),
          ),
        ),
      ];
    }

    return [
      SizedBox(
        width: double.infinity,
        height: 64,
        child: OutlinedButton.icon(
          onPressed: disabled ? null : () => _runAction(() => _service.breakStart(token)),
          icon: const Icon(Icons.free_breakfast, size: 28),
          label: const Text('Pause beginnen', style: TextStyle(fontSize: 18)),
        ),
      ),
      const SizedBox(height: 16),
      SizedBox(
        width: double.infinity,
        height: 72,
        child: FilledButton.icon(
          style: FilledButton.styleFrom(backgroundColor: Colors.red[700]),
          onPressed: disabled ? null : () => _runAction(() => _service.stampOut(token)),
          icon: const Icon(Icons.logout, size: 32),
          label: const Text('Ausstempeln', style: TextStyle(fontSize: 20)),
        ),
      ),
    ];
  }
}