farolero/lib/pantallas/pantalla_unirse.dart

import 'package:flutter/material.dart';
import 'package:mobile_scanner/mobile_scanner.dart';
import 'package:provider/provider.dart';
import 'package:farolero/l10n/generated/app_localizations.dart';
import '../servicios/servicio_nearby.dart';
import '../servicios/servicio_permisos.dart';
import '../tema/tema_app.dart';

/// Pantalla para unirse a una partida multidispositivo.
/// Flujo: nombre → discovery automático (lista de salas) → fallback QR
class PantallaUnirse extends StatefulWidget {
  const PantallaUnirse({super.key});

  @override
  State<PantallaUnirse> createState() => _PantallaUnirseState();
}

class _PantallaUnirseState extends State<PantallaUnirse> {
  final _nombreController = TextEditingController();
  final _formKey = GlobalKey<FormState>();

  // Estados de la pantalla
  bool _buscando = false;
  bool _escaneandoQR = false;
  bool _conectando = false;
  String? _error;
  String? _salaSeleccionada;

  @override
  void dispose() {
    _nombreController.dispose();
    super.dispose();
  }

  /// Paso 1: validar nombre, pedir permisos e iniciar discovery
  Future<void> _iniciarBusqueda() async {
    if (!_formKey.currentState!.validate()) return;

    // Solicitar permisos automáticamente
    final permisosOk = await ServicioPermisos.solicitarPermisosNearby(context);
    if (!permisosOk) {
      setState(() {
        _error = 'Se necesitan permisos de Bluetooth y ubicación para buscar partidas.';
      });
      return;
    }

    if (!mounted) return;
    final nearby = context.read<ServicioNearby>();
    final ok = await nearby.buscarHosts(_nombreController.text.trim());

    if (ok) {
      setState(() {
        _buscando = true;
        _error = null;
      });
    } else {
      setState(() {
        _error = 'No se pudo iniciar la búsqueda. Verifica Bluetooth y ubicación.';
      });
    }
  }

  /// Conectar a un host de la lista
  Future<void> _conectarAHost(String endpointId, String nombreHost) async {
    setState(() {
      _conectando = true;
      _salaSeleccionada = nombreHost;
    });

    final nearby = context.read<ServicioNearby>();
    // Parar discovery antes de conectar
    await nearby.pararBusqueda();
    final ok = await nearby.conectarAHost(endpointId, _nombreController.text.trim());

    if (!ok && mounted) {
      setState(() {
        _conectando = false;
        _error = 'No se pudo conectar a $nombreHost';
      });
      // Reiniciar búsqueda
      _iniciarBusqueda();
    }
  }

  /// Fallback: escanear QR
  void _abrirEscaner() {
    setState(() {
      _escaneandoQR = true;
      _error = null;
    });
  }

  Future<void> _onQRDetectado(BarcodeCapture capture) async {
    if (_conectando) return;

    for (final barcode in capture.barcodes) {
      final valor = barcode.rawValue;
      if (valor == null) continue;

      final datos = ServicioNearby.parsearQR(valor);
      if (datos != null) {
        setState(() {
          _escaneandoQR = false;
          _conectando = true;
          _salaSeleccionada = datos['host'] as String? ?? datos['sala'] as String? ?? 'Sala';
        });

        // Iniciar búsqueda para que Nearby encuentre al host
        final nearby = context.read<ServicioNearby>();
        if (!nearby.buscando) {
          await nearby.buscarHosts(_nombreController.text.trim());
        }
        return;
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final nearby = context.watch<ServicioNearby>();

    // Si estamos conectados → pantalla de espera
    if (nearby.conectado && !nearby.esHost) {
      return _buildPantallaEspera(context, l10n);
    }

    // Si escaneando QR
    if (_escaneandoQR) {
      return _buildEscaner(context, l10n);
    }

    // Si buscando hosts o conectando
    if (_buscando || _conectando) {
      return _buildDiscovery(context, l10n, nearby);
    }

    // Formulario nombre
    return _buildFormularioNombre(context, l10n);
  }

  // ==================== PASO 1: NOMBRE ====================

  Widget _buildFormularioNombre(BuildContext context, AppLocalizations l10n) {
    return Scaffold(
      appBar: AppBar(
        title: Text(l10n.joinGameTitle),
      ),
      body: Padding(
        padding: const EdgeInsets.all(32),
        child: Form(
          key: _formKey,
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              const Text('📱', style: TextStyle(fontSize: 64)),
              const SizedBox(height: 24),
              Text(
                l10n.joinGameTitle,
                style: Theme.of(context).textTheme.headlineMedium,
              ),
              const SizedBox(height: 8),
              Text(
                l10n.enterNameToSearch,
                style: Theme.of(context).textTheme.bodyLarge,
                textAlign: TextAlign.center,
              ),
              const SizedBox(height: 32),
              TextFormField(
                controller: _nombreController,
                decoration: InputDecoration(
                  labelText: l10n.yourName,
                  prefixIcon: const Icon(Icons.person),
                ),
                validator: (v) {
                  if (v == null || v.trim().isEmpty) return l10n.nameRequired;
                  return null;
                },
                textCapitalization: TextCapitalization.words,
                onFieldSubmitted: (_) => _iniciarBusqueda(),
              ),
              const SizedBox(height: 24),
              SizedBox(
                width: double.infinity,
                child: ElevatedButton.icon(
                  onPressed: _iniciarBusqueda,
                  icon: const Icon(Icons.search),
                  label: Text(l10n.searchGames),
                ),
              ),
              if (_error != null) ...[
                const SizedBox(height: 16),
                _buildError(_error!),
              ],
            ],
          ),
        ),
      ),
    );
  }

  // ==================== PASO 2: DISCOVERY ====================

  Widget _buildDiscovery(BuildContext context, AppLocalizations l10n, ServicioNearby nearby) {
    final hosts = nearby.hostsEncontrados;

    return Scaffold(
      appBar: AppBar(
        title: Text(l10n.joinGameTitle),
        leading: IconButton(
          icon: const Icon(Icons.arrow_back),
          onPressed: () async {
            await nearby.pararBusqueda();
            setState(() {
              _buscando = false;
              _conectando = false;
            });
          },
        ),
      ),
      body: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          children: [
            // Estado
            if (_conectando) ...[
              const CircularProgressIndicator(color: TemaApp.colorAcento),
              const SizedBox(height: 12),
              Text(
                '${l10n.connectingTo} ${_salaSeleccionada ?? ""}...',
                style: Theme.of(context).textTheme.bodyLarge,
              ),
              const SizedBox(height: 24),
            ] else ...[
              // Buscando
              Row(
                children: [
                  const SizedBox(
                    width: 20, height: 20,
                    child: CircularProgressIndicator(
                      strokeWidth: 2,
                      color: TemaApp.colorNaranja,
                    ),
                  ),
                  const SizedBox(width: 12),
                  Text(
                    l10n.searchingGames,
                    style: Theme.of(context).textTheme.titleMedium,
                  ),
                ],
              ),
              const SizedBox(height: 24),
            ],

            // Lista de hosts encontrados
            Expanded(
              child: hosts.isEmpty && !_conectando
                  ? Center(
                      child: Column(
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          const Text('📡', style: TextStyle(fontSize: 48)),
                          const SizedBox(height: 16),
                          Text(
                            l10n.noGamesFound,
                            style: Theme.of(context).textTheme.bodyLarge,
                            textAlign: TextAlign.center,
                          ),
                          const SizedBox(height: 8),
                          Text(
                            l10n.noGamesFoundHint,
                            style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                              color: Colors.grey,
                            ),
                            textAlign: TextAlign.center,
                          ),
                        ],
                      ),
                    )
                  : ListView.builder(
                      itemCount: hosts.length,
                      itemBuilder: (context, index) {
                        final entry = hosts.entries.elementAt(index);
                        return _buildHostTile(entry.key, entry.value);
                      },
                    ),
            ),

            if (_error != null) ...[
              _buildError(_error!),
              const SizedBox(height: 12),
            ],

            // Fallback: escanear QR
            if (!_conectando) ...[
              const Divider(),
              const SizedBox(height: 8),
              Text(
                l10n.orScanQR,
                style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                  color: Colors.grey,
                ),
              ),
              const SizedBox(height: 8),
              SizedBox(
                width: double.infinity,
                child: OutlinedButton.icon(
                  onPressed: _abrirEscaner,
                  icon: const Icon(Icons.qr_code_scanner),
                  label: Text(l10n.scanQR),
                ),
              ),
            ],
          ],
        ),
      ),
    );
  }

  Widget _buildHostTile(String endpointId, String nombre) {
    return Container(
      margin: const EdgeInsets.only(bottom: 8),
      child: Material(
        color: TemaApp.colorTarjeta,
        borderRadius: BorderRadius.circular(12),
        child: InkWell(
          borderRadius: BorderRadius.circular(12),
          onTap: _conectando ? null : () => _conectarAHost(endpointId, nombre),
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 16),
            child: Row(
              children: [
                const Text('🎭', style: TextStyle(fontSize: 28)),
                const SizedBox(width: 16),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(
                        nombre,
                        style: Theme.of(context).textTheme.titleMedium,
                      ),
                      Text(
                        'Toca para unirte',
                        style: Theme.of(context).textTheme.bodySmall?.copyWith(
                          color: Colors.grey,
                        ),
                      ),
                    ],
                  ),
                ),
                const Icon(Icons.arrow_forward_ios, size: 16, color: Colors.grey),
              ],
            ),
          ),
        ),
      ),
    );
  }

  // ==================== ESCÁNER QR ====================

  Widget _buildEscaner(BuildContext context, AppLocalizations l10n) {
    return Scaffold(
      appBar: AppBar(
        title: Text(l10n.scanQR),
        leading: IconButton(
          icon: const Icon(Icons.arrow_back),
          onPressed: () => setState(() => _escaneandoQR = false),
        ),
      ),
      body: Stack(
        children: [
          MobileScanner(onDetect: _onQRDetectado),
          Positioned(
            bottom: 0,
            left: 0,
            right: 0,
            child: Container(
              padding: const EdgeInsets.all(24),
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment.topCenter,
                  end: Alignment.bottomCenter,
                  colors: [
                    Colors.transparent,
                    Colors.black.withValues(alpha: 0.8),
                  ],
                ),
              ),
              child: Text(
                l10n.scanHostQR,
                style: Theme.of(context).textTheme.titleLarge?.copyWith(
                  color: Colors.white,
                ),
                textAlign: TextAlign.center,
              ),
            ),
          ),
        ],
      ),
    );
  }

  // ==================== ESPERA ====================

  Widget _buildPantallaEspera(BuildContext context, AppLocalizations l10n) {
    return Scaffold(
      appBar: AppBar(
        title: Text(_salaSeleccionada ?? l10n.joinGameTitle),
        leading: IconButton(
          icon: const Icon(Icons.close),
          onPressed: () async {
            final nearby = context.read<ServicioNearby>();
            await nearby.desconectar();
            if (context.mounted) {
              setState(() {
                _buscando = false;
                _conectando = false;
              });
            }
          },
        ),
      ),
      body: Center(
        child: Padding(
          padding: const EdgeInsets.all(32),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              const Text('✅', style: TextStyle(fontSize: 64)),
              const SizedBox(height: 24),
              Text(
                l10n.connectedWaiting,
                style: Theme.of(context).textTheme.headlineMedium,
                textAlign: TextAlign.center,
              ),
              const SizedBox(height: 12),
              Text(
                '${l10n.yourName}: ${_nombreController.text}',
                style: Theme.of(context).textTheme.bodyLarge,
              ),
              const SizedBox(height: 32),
              const CircularProgressIndicator(color: TemaApp.colorNaranja),
              const SizedBox(height: 16),
              Text(
                l10n.waitingForHost,
                style: Theme.of(context).textTheme.bodyMedium,
              ),
            ],
          ),
        ),
      ),
    );
  }

  // ==================== HELPERS ====================

  Widget _buildError(String msg) {
    return Container(
      padding: const EdgeInsets.all(12),
      decoration: BoxDecoration(
        color: TemaApp.colorAcento.withValues(alpha: 0.1),
        borderRadius: BorderRadius.circular(12),
      ),
      child: Text(
        msg,
        style: const TextStyle(color: TemaApp.colorAcento),
        textAlign: TextAlign.center,
      ),
    );
  }
}