import 'dart:async';

import 'package:sysfarma_mobile/src/app/widgets/app_hero_card.dart';
import 'package:sysfarma_mobile/src/app/widgets/app_loader.dart';
import 'package:sysfarma_mobile/src/app/widgets/app_panel.dart';
import 'package:sysfarma_mobile/src/app/widgets/empty_state_panel.dart';
import 'package:sysfarma_mobile/src/core/network/api_client.dart';
import 'package:sysfarma_mobile/src/core/network/mobile_api_response.dart';
import 'package:sysfarma_mobile/src/core/theme/app_tokens.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

String _formatCurrency(Object? value) {
  if (value == null) return 'S/ 0.00';
  final n = double.tryParse(value.toString()) ?? 0.0;
  final formatted = n.toStringAsFixed(2).replaceAllMapped(
    RegExp(r'(\d{1,3})(?=(\d{3})+(?!\d))'),
    (m) => '${m[1]},',
  );
  return 'S/ $formatted';
}

class InventoryScreen extends ConsumerStatefulWidget {
  const InventoryScreen({super.key});

  @override
  ConsumerState<InventoryScreen> createState() => _InventoryScreenState();
}

/// Filtro activo para la lista de inventario.
enum _StockFilter { all, outOfStock, lowStock }

class _InventoryScreenState extends ConsumerState<InventoryScreen> {
  static const int _pageSize = 15;

  late Future<_InventoryBundle> _future;
  final ScrollController _scrollController = ScrollController();

  // Paginación acumulada de items
  final List<Map<String, dynamic>> _accumulatedItems = [];
  int _currentPage = 1;
  bool _hasMore = true;
  bool _isLoadingMore = false;

  // Filtro activo
  _StockFilter _activeFilter = _StockFilter.all;

  @override
  void initState() {
    super.initState();
    _future = _load();
  }

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

  Future<_InventoryBundle> _load() async {
    try {
      _currentPage = 1;
      _accumulatedItems.clear();
      _hasMore = true;

      final api = ref.read(apiClientProvider);
      final stock = await api.inventoryStock(page: 1, perPage: _pageSize);
      final options = await api.inventoryOptions();

      // Almacenar la primera página en el acumulado
      if (stock.success) {
        _accumulatedItems.addAll(stock.data ?? const []);
        _hasMore = (stock.meta['has_more'] == true);
      }

      return _InventoryBundle(
        stock: stock,
        options: options,
      );
    } catch (e) {
      return _InventoryBundle(
        stock: MobileApiResponse.failure(message: e.toString()),
        options: MobileApiResponse.failure(message: e.toString()),
      );
    }
  }

  Future<void> _loadMore() async {
    if (_isLoadingMore || !_hasMore) return;
    setState(() => _isLoadingMore = true);
    try {
      final api = ref.read(apiClientProvider);
      final nextPage = _currentPage + 1;
      final response = await api.inventoryStock(page: nextPage, perPage: _pageSize);
      if (!mounted) return;
      if (response.success) {
        setState(() {
          _accumulatedItems.addAll(response.data ?? const []);
          _currentPage = nextPage;
          _hasMore = (response.meta['has_more'] == true);
          _isLoadingMore = false;
        });
      } else {
        setState(() => _isLoadingMore = false);
      }
    } catch (_) {
      if (mounted) setState(() => _isLoadingMore = false);
    }
  }

  Future<void> _refresh() async {
    final future = _load();
    setState(() {
      _future = future;
      _activeFilter = _StockFilter.all;
    });
    await future;
  }

  List<Map<String, dynamic>> _filteredItems() {
    switch (_activeFilter) {
      case _StockFilter.outOfStock:
        return _accumulatedItems
            .where((i) => _toDouble(i['stock']) <= 0)
            .toList();
      case _StockFilter.lowStock:
        return _accumulatedItems
            .where((i) =>
                _toDouble(i['stock']) > 0 &&
                _toDouble(i['stock']) <= _toDouble(i['stock_min']))
            .toList();
      case _StockFilter.all:
        return _accumulatedItems;
    }
  }

  void _toggleFilter(_StockFilter filter) {
    setState(() {
      _activeFilter = _activeFilter == filter ? _StockFilter.all : filter;
    });
  }

  void _showMessage(String message, {bool isError = false}) {
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(message),
        backgroundColor: isError ? AppTokens.danger : null,
      ),
    );
  }

  List<Map<String, dynamic>> _transactionsForType(
    List<Map<String, dynamic>> transactions,
    String type,
  ) {
    return transactions.where((item) => item['type']?.toString() == type).toList();
  }

  Future<void> _showItemDetailSheet(Map<String, dynamic> item) async {
    final stock = double.tryParse('${item['stock']}') ?? 0;
    final stockMin = double.tryParse('${item['stock_min']}') ?? 0;
    final riskColor = stock <= 0
        ? AppTokens.danger
        : stock <= stockMin
            ? AppTokens.warning
            : AppTokens.success;
    final statusLabel = stock <= 0
        ? 'Agotado'
        : stock <= stockMin
            ? 'Stock bajo'
            : 'Disponible';

    await showModalBottomSheet<void>(
      context: context,
      isScrollControlled: true,
      builder: (sheetContext) {
        return SafeArea(
          child: SingleChildScrollView(
            padding: const EdgeInsets.fromLTRB(20, 8, 20, 24),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(
                  children: [
                    CircleAvatar(
                      radius: 24,
                      backgroundColor: riskColor.withValues(alpha: 0.12),
                      foregroundColor: riskColor,
                      child: const Icon(Icons.medication_liquid_rounded),
                    ),
                    const SizedBox(width: 14),
                    Expanded(
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Text(
                            item['description']?.toString() ?? 'Producto',
                            style: Theme.of(context).textTheme.titleLarge,
                          ),
                          const SizedBox(height: 4),
                          Container(
                            padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
                            decoration: BoxDecoration(
                              color: riskColor.withValues(alpha: 0.12),
                              borderRadius: BorderRadius.circular(999),
                            ),
                            child: Text(
                              statusLabel,
                              style: Theme.of(context).textTheme.labelSmall?.copyWith(
                                    color: riskColor,
                                    fontWeight: FontWeight.w700,
                                  ),
                            ),
                          ),
                        ],
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 20),
                _DetailRow(
                  icon: Icons.inventory_2_rounded,
                  label: 'Stock actual',
                  value: '${item['stock'] ?? 0} uds',
                  color: riskColor,
                ),
                const Divider(height: 24),
                _DetailRow(
                  icon: Icons.warning_amber_rounded,
                  label: 'Stock mínimo',
                  value: '${item['stock_min'] ?? 0} uds',
                ),
                const Divider(height: 24),
                _DetailRow(
                  icon: Icons.shopping_bag_rounded,
                  label: 'Precio compra',
                  value: _formatCurrency(item['purchase_unit_price']),
                ),
                const Divider(height: 24),
                _DetailRow(
                  icon: Icons.sell_rounded,
                  label: 'Precio venta',
                  value: _formatCurrency(item['sale_unit_price']),
                  color: AppTokens.primary,
                ),
                const Divider(height: 24),
                _DetailRow(
                  icon: Icons.account_balance_wallet_rounded,
                  label: 'Costo en inventario',
                  value: _formatCurrency(item['stock_cost_value']),
                ),
                const Divider(height: 24),
                _DetailRow(
                  icon: Icons.point_of_sale_rounded,
                  label: 'Valor de venta',
                  value: _formatCurrency(item['stock_sale_value']),
                ),
                const Divider(height: 24),
                _DetailRow(
                  icon: Icons.trending_up_rounded,
                  label: 'Utilidad potencial',
                  value: _formatCurrency(item['potential_profit']),
                  color: riskColor,
                ),
                if ((item['category_name']?.toString() ?? '').isNotEmpty) ...[
                  const Divider(height: 24),
                  _DetailRow(
                    icon: Icons.category_rounded,
                    label: 'Categoría',
                    value: item['category_name'].toString(),
                  ),
                ],
                if ((item['brand_name']?.toString() ?? '').isNotEmpty) ...[
                  const Divider(height: 24),
                  _DetailRow(
                    icon: Icons.bookmark_rounded,
                    label: 'Marca',
                    value: item['brand_name'].toString(),
                  ),
                ],
                const SizedBox(height: 20),
                SizedBox(
                  width: double.infinity,
                  child: FilledButton.icon(
                    onPressed: () {
                      Navigator.of(sheetContext).pop();
                    },
                    icon: const Icon(Icons.close_rounded),
                    label: const Text('Cerrar'),
                  ),
                ),
              ],
            ),
          ),
        );
      },
    );
  }

  Future<void> _openMovementForm({
    required List<Map<String, dynamic>> warehouses,
    required List<Map<String, dynamic>> transactions,
    Map<String, dynamic>? preSelectedItem,
  }) async {
    if (warehouses.isEmpty || transactions.isEmpty) {
      _showMessage('No hay almacenes o transacciones disponibles para registrar movimientos.', isError: true);
      return;
    }

    final preCode = preSelectedItem?['internal_id']?.toString();
    final preItemId = preSelectedItem != null
        ? int.tryParse('${preSelectedItem['item_id'] ?? preSelectedItem['id']}')
        : null;
    final preName = preSelectedItem?['description']?.toString() ??
        preSelectedItem?['full_description']?.toString();
    final preLotsEnabled = preSelectedItem?['lots_enabled'] == true;
    final preText = (preName != null && preName.isNotEmpty)
        ? (preCode != null && preCode.isNotEmpty ? '$preCode - $preName' : preName)
        : (preCode ?? '');

    final itemSearchController = TextEditingController(text: preText);
    final quantityController = TextEditingController();
    final lotCodeController = TextEditingController();
    final dateOfDueController = TextEditingController();
    final formKey = GlobalKey<FormState>();
    String selectedType = 'input';
    int? selectedWarehouseId = int.tryParse('${warehouses.first['id']}');
    final initialTransactions = _transactionsForType(transactions, 'input');
    int? selectedTransactionId = initialTransactions.isEmpty ? null : int.tryParse('${initialTransactions.first['id']}');
    String? errorText;
    var isSubmitting = false;

    // Search state
    String? selectedItemCode = preCode;
    int? selectedItemId = preItemId;
    String? selectedItemName = preName;
    bool selectedItemLotsEnabled = preLotsEnabled;
    List<Map<String, dynamic>> searchResults = [];
    bool isSearching = false;
    Timer? searchDebounce;

    // Autocompletado de lotes ya registrados del producto seleccionado.
    List<Map<String, dynamic>> lotSuggestions = [];
    bool isSearchingLots = false;
    bool showLotSuggestions = false;
    Timer? lotSearchDebounce;

    Future<void> searchLots(String query, void Function(void Function()) setSheetState) async {
      if (selectedItemId == null) return;
      setSheetState(() => isSearchingLots = true);
      final response = await ref.read(apiClientProvider).itemLots(
            itemId: selectedItemId!,
            query: query,
          );
      setSheetState(() {
        isSearchingLots = false;
        lotSuggestions = response.success ? (response.data ?? const []) : const [];
      });
    }

    await showModalBottomSheet<void>(
      context: context,
      isScrollControlled: true,
      builder: (context) {
        return StatefulBuilder(
          builder: (context, setSheetState) {
            final currentTransactions = _transactionsForType(transactions, selectedType);
            selectedTransactionId ??= currentTransactions.isEmpty ? null : int.tryParse('${currentTransactions.first['id']}');

            Future<void> submit() async {
              if (!(formKey.currentState?.validate() ?? false) || isSubmitting) {
                return;
              }

              setSheetState(() {
                isSubmitting = true;
                errorText = null;
              });

              // Validación de lote obligatorio (código + fecha de vencimiento,
              // igual que en la web).
              if (selectedItemLotsEnabled && selectedType == 'input') {
                if (lotCodeController.text.trim().isEmpty) {
                  setSheetState(() {
                    isSubmitting = false;
                    errorText = 'Este producto requiere código de lote.';
                  });
                  return;
                }
                if (dateOfDueController.text.trim().isEmpty) {
                  setSheetState(() {
                    isSubmitting = false;
                    errorText = 'Ingresa la fecha de vencimiento del lote.';
                  });
                  return;
                }
              }

              final response = await ref.read(apiClientProvider).createInventoryMovement(
                    itemCode: selectedItemCode,
                    itemId: selectedItemId,
                    warehouseId: selectedWarehouseId ?? 0,
                    inventoryTransactionId: selectedTransactionId ?? 0,
                    quantity: double.tryParse(quantityController.text.trim()) ?? 0,
                    type: selectedType,
                    lotCode: lotCodeController.text.trim().isEmpty
                        ? null
                        : lotCodeController.text.trim(),
                    dateOfDue: dateOfDueController.text.trim().isEmpty
                        ? null
                        : dateOfDueController.text.trim(),
                  );

              if (!response.success) {
                setSheetState(() {
                  isSubmitting = false;
                  errorText = response.message ?? 'No se pudo registrar el movimiento.';
                });
                return;
              }

              // Disparar el refresh ANTES de cerrar el sheet para que el State
              // del screen actualice su future inmediatamente.
              // No await aquí para no bloquear el pop.
              // ignore: discarded_futures
              _refresh();

              if (!context.mounted) return;
              if (Navigator.of(context).canPop()) {
                Navigator.of(context).pop();
              }
              _showMessage(response.message ?? 'Movimiento registrado.');
            }

            return SafeArea(
              child: SingleChildScrollView(
                padding: EdgeInsets.fromLTRB(
                  20,
                  8,
                  20,
                  24 + MediaQuery.of(context).viewInsets.bottom,
                ),
                child: Form(
                  key: formKey,
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text('Nuevo movimiento', style: Theme.of(context).textTheme.headlineSmall),
                      const SizedBox(height: 8),
                      Text(
                        'Registra ingresos o salidas usando el API movil real de inventario.',
                        style: Theme.of(context).textTheme.bodyMedium?.copyWith(color: AppTokens.secondary),
                      ),
                      const SizedBox(height: 18),
                      DropdownButtonFormField<String>(
                        initialValue: selectedType,
                        isExpanded: true,
                        items: const [
                          DropdownMenuItem(value: 'input', child: Text('Ingreso', overflow: TextOverflow.ellipsis)),
                          DropdownMenuItem(value: 'output', child: Text('Salida', overflow: TextOverflow.ellipsis)),
                        ],
                        onChanged: (value) {
                          if (value == null) {
                            return;
                          }
                          setSheetState(() {
                            selectedType = value;
                            final filtered = _transactionsForType(transactions, value);
                            selectedTransactionId = filtered.isEmpty ? null : int.tryParse('${filtered.first['id']}');
                          });
                        },
                        decoration: const InputDecoration(
                          labelText: 'Tipo de movimiento',
                          prefixIcon: Icon(Icons.swap_vert_rounded),
                        ),
                      ),
                      // Con un solo almacén disponible (el caso normal: cada
                      // usuario ya está atado a su sede) no tiene sentido
                      // mostrar un selector — se usa directo y sin fricción.
                      // Solo un admin/owner con varios almacenes ve el combo.
                      if (warehouses.length > 1) ...[
                        const SizedBox(height: 14),
                        DropdownButtonFormField<int>(
                          initialValue: selectedWarehouseId,
                          isExpanded: true,
                          items: warehouses
                              .map(
                                (item) => DropdownMenuItem<int>(
                                  value: int.tryParse('${item['id']}'),
                                  child: Text(
                                    item['description']?.toString() ?? 'Almacen',
                                    overflow: TextOverflow.ellipsis,
                                  ),
                                ),
                              )
                              .toList(),
                          onChanged: (value) => setSheetState(() => selectedWarehouseId = value),
                          decoration: const InputDecoration(
                            labelText: 'Almacen',
                            prefixIcon: Icon(Icons.warehouse_rounded),
                          ),
                        ),
                      ],
                      const SizedBox(height: 14),
                      DropdownButtonFormField<int>(
                        initialValue: selectedTransactionId,
                        isExpanded: true,
                        items: currentTransactions
                            .map(
                              (item) => DropdownMenuItem<int>(
                                value: int.tryParse('${item['id']}'),
                                child: Text(
                                  item['name']?.toString() ?? 'Transaccion',
                                  overflow: TextOverflow.ellipsis,
                                ),
                              ),
                            )
                            .toList(),
                        onChanged: (value) => setSheetState(() => selectedTransactionId = value),
                        decoration: const InputDecoration(
                          labelText: 'Transaccion',
                          prefixIcon: Icon(Icons.category_rounded),
                        ),
                        validator: (value) {
                          if (value == null) {
                            return 'Selecciona una transaccion.';
                          }
                          return null;
                        },
                      ),
                      const SizedBox(height: 14),
                      TextFormField(
                        controller: itemSearchController,
                        decoration: InputDecoration(
                          labelText: 'Buscar producto (nombre o código)',
                          hintText: 'Escribe al menos 2 caracteres...',
                          prefixIcon: const Icon(Icons.search_rounded),
                          suffixIcon: (selectedItemId != null || selectedItemCode != null)
                              ? IconButton(
                                  icon: const Icon(Icons.clear_rounded),
                                  onPressed: () {
                                    setSheetState(() {
                                      itemSearchController.clear();
                                      selectedItemCode = null;
                                      selectedItemId = null;
                                      selectedItemName = null;
                                      selectedItemLotsEnabled = false;
                                      lotCodeController.clear();
                                      dateOfDueController.clear();
                                      lotSuggestions = [];
                                      showLotSuggestions = false;
                                      searchResults = [];
                                    });
                                  },
                                )
                              : (isSearching
                                  ? const Padding(
                                      padding: EdgeInsets.all(12),
                                      child: SizedBox(
                                        width: 18,
                                        height: 18,
                                        child: CircularProgressIndicator(strokeWidth: 2),
                                      ),
                                    )
                                  : null),
                        ),
                        onChanged: (value) {
                          // Si hay un item ya seleccionado y el usuario cambia el texto,
                          // limpiar la selección
                          if (selectedItemId != null || selectedItemCode != null) {
                            setSheetState(() {
                              selectedItemCode = null;
                              selectedItemId = null;
                              selectedItemName = null;
                              selectedItemLotsEnabled = false;
                            });
                          }
                          searchDebounce?.cancel();
                          final query = value.trim();
                          if (query.length < 2) {
                            setSheetState(() {
                              searchResults = [];
                              isSearching = false;
                            });
                            return;
                          }
                          setSheetState(() => isSearching = true);
                          searchDebounce = Timer(
                            const Duration(milliseconds: 400),
                            () async {
                              final api = ref.read(apiClientProvider);
                              final response = await api.items(
                                perPage: 10,
                                page: 1,
                                search: query,
                                context: 'inventory',
                              );
                              setSheetState(() {
                                isSearching = false;
                                searchResults = response.success
                                    ? (response.data ?? const [])
                                    : const [];
                              });
                            },
                          );
                        },
                        validator: (value) {
                          if ((value == null || value.trim().isEmpty) &&
                              selectedItemCode == null) {
                            return 'Busca y selecciona un producto.';
                          }
                          return null;
                        },
                      ),
                      if (selectedItemName != null) ...[
                        const SizedBox(height: 6),
                        Container(
                          padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
                          decoration: BoxDecoration(
                            color: AppTokens.success.withValues(alpha: 0.10),
                            borderRadius: BorderRadius.circular(8),
                            border: Border.all(color: AppTokens.success.withValues(alpha: 0.4)),
                          ),
                          child: Row(
                            children: [
                              const Icon(Icons.check_circle_rounded, size: 16, color: AppTokens.success),
                              const SizedBox(width: 8),
                              Expanded(
                                child: Text(
                                  selectedItemName!,
                                  maxLines: 2,
                                  overflow: TextOverflow.ellipsis,
                                  style: Theme.of(context).textTheme.bodySmall?.copyWith(
                                        color: AppTokens.textPrimary,
                                        fontWeight: FontWeight.w600,
                                      ),
                                ),
                              ),
                              if (selectedItemLotsEnabled)
                                Container(
                                  margin: const EdgeInsets.only(left: 8),
                                  padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
                                  decoration: BoxDecoration(
                                    color: AppTokens.warning.withValues(alpha: 0.15),
                                    borderRadius: BorderRadius.circular(4),
                                  ),
                                  child: Text(
                                    'LOTE',
                                    style: Theme.of(context).textTheme.labelSmall?.copyWith(
                                          color: AppTokens.warning,
                                          fontWeight: FontWeight.w700,
                                          fontSize: 10,
                                        ),
                                  ),
                                ),
                            ],
                          ),
                        ),
                      ],
                      if (selectedItemLotsEnabled && selectedType == 'input') ...[
                        const SizedBox(height: 14),
                        TextFormField(
                          controller: lotCodeController,
                          decoration: InputDecoration(
                            labelText: 'Código de lote *',
                            hintText: 'Ej: LOT-2026-001',
                            prefixIcon: const Icon(Icons.qr_code_2_rounded),
                            helperText: 'Este producto requiere lote. Toca para ver lotes ya registrados.',
                            suffixIcon: isSearchingLots
                                ? const Padding(
                                    padding: EdgeInsets.all(12),
                                    child: SizedBox(
                                      width: 18,
                                      height: 18,
                                      child: CircularProgressIndicator(strokeWidth: 2),
                                    ),
                                  )
                                : null,
                          ),
                          onTap: () {
                            // Al tocar el campo, precargar los lotes ya
                            // registrados de este producto (igual que el
                            // buscador de lotes de la web).
                            setSheetState(() => showLotSuggestions = true);
                            if (lotSuggestions.isEmpty) {
                              // ignore: discarded_futures
                              searchLots(lotCodeController.text.trim(), setSheetState);
                            }
                          },
                          onChanged: (value) {
                            setSheetState(() => showLotSuggestions = true);
                            lotSearchDebounce?.cancel();
                            lotSearchDebounce = Timer(
                              const Duration(milliseconds: 350),
                              () => searchLots(value.trim(), setSheetState),
                            );
                          },
                          validator: (value) {
                            if (selectedItemLotsEnabled &&
                                selectedType == 'input' &&
                                (value == null || value.trim().isEmpty)) {
                              return 'Ingresa el código del lote.';
                            }
                            return null;
                          },
                        ),
                        if (showLotSuggestions && lotSuggestions.isNotEmpty) ...[
                          const SizedBox(height: 6),
                          Container(
                            constraints: const BoxConstraints(maxHeight: 200),
                            decoration: BoxDecoration(
                              color: AppTokens.surface,
                              borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
                              border: Border.all(color: AppTokens.border),
                            ),
                            child: ListView.separated(
                              shrinkWrap: true,
                              padding: EdgeInsets.zero,
                              itemCount: lotSuggestions.length,
                              separatorBuilder: (_, __) => const Divider(height: 1),
                              itemBuilder: (context, index) {
                                final lot = lotSuggestions[index];
                                final code = lot['code']?.toString() ?? '';
                                final due = lot['date_of_due']?.toString();
                                final qty = lot['quantity'];
                                return ListTile(
                                  dense: true,
                                  leading: const Icon(Icons.qr_code_2_rounded, size: 20),
                                  title: Text(code, style: Theme.of(context).textTheme.bodyMedium),
                                  subtitle: Text(
                                    [
                                      if (due != null && due.isNotEmpty) 'Vence: $due',
                                      if (qty != null) 'Stock: $qty',
                                    ].join(' · '),
                                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
                                          color: AppTokens.textSecondary,
                                        ),
                                  ),
                                  onTap: () {
                                    setSheetState(() {
                                      lotCodeController.text = code;
                                      dateOfDueController.text = due ?? '';
                                      showLotSuggestions = false;
                                    });
                                    FocusScope.of(context).unfocus();
                                  },
                                );
                              },
                            ),
                          ),
                        ],
                        const SizedBox(height: 14),
                        TextFormField(
                          controller: dateOfDueController,
                          readOnly: true,
                          decoration: const InputDecoration(
                            labelText: 'Fecha de vencimiento *',
                            hintText: 'YYYY-MM-DD',
                            prefixIcon: Icon(Icons.event_rounded),
                          ),
                          onTap: () async {
                            final picked = await showDatePicker(
                              context: context,
                              initialDate: DateTime.now().add(const Duration(days: 365)),
                              firstDate: DateTime.now(),
                              lastDate: DateTime.now().add(const Duration(days: 365 * 10)),
                              locale: const Locale('es'),
                              helpText: 'Fecha de vencimiento',
                              cancelText: 'Cancelar',
                              confirmText: 'Aceptar',
                            );
                            if (picked != null) {
                              setSheetState(() {
                                dateOfDueController.text =
                                    '${picked.year.toString().padLeft(4, '0')}-${picked.month.toString().padLeft(2, '0')}-${picked.day.toString().padLeft(2, '0')}';
                              });
                            }
                          },
                          validator: (value) {
                            if (selectedItemLotsEnabled &&
                                selectedType == 'input' &&
                                (value == null || value.trim().isEmpty)) {
                              return 'Ingresa la fecha de vencimiento.';
                            }
                            return null;
                          },
                        ),
                      ],
                      if (searchResults.isNotEmpty && selectedItemCode == null) ...[
                        const SizedBox(height: 8),
                        Container(
                          constraints: const BoxConstraints(maxHeight: 240),
                          decoration: BoxDecoration(
                            color: AppTokens.surface,
                            borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
                            border: Border.all(color: AppTokens.border),
                          ),
                          child: ListView.separated(
                            shrinkWrap: true,
                            padding: EdgeInsets.zero,
                            itemCount: searchResults.length,
                            separatorBuilder: (_, __) => const Divider(height: 1),
                            itemBuilder: (context, index) {
                              final item = searchResults[index];
                              final code = item['internal_id']?.toString() ?? '';
                              final description = item['description']?.toString() ??
                                  item['full_description']?.toString() ??
                                  'Producto';
                              return ListTile(
                                dense: true,
                                leading: const Icon(Icons.inventory_2_rounded, size: 20),
                                title: Text(
                                  description,
                                  maxLines: 2,
                                  overflow: TextOverflow.ellipsis,
                                  style: Theme.of(context).textTheme.bodyMedium,
                                ),
                                subtitle: Text(
                                  'Código: $code',
                                  style: Theme.of(context).textTheme.bodySmall?.copyWith(
                                        color: AppTokens.textSecondary,
                                      ),
                                ),
                                onTap: () {
                                  setSheetState(() {
                                    selectedItemCode = code.isEmpty ? null : code;
                                    selectedItemId = int.tryParse('${item['id'] ?? item['item_id'] ?? ''}');
                                    selectedItemName = description;
                                    selectedItemLotsEnabled = item['lots_enabled'] == true;
                                    itemSearchController.text = code.isNotEmpty
                                        ? '$code - $description'
                                        : description;
                                    searchResults = [];
                                    // Nuevo producto: los lotes del anterior ya no aplican.
                                    lotCodeController.clear();
                                    dateOfDueController.clear();
                                    lotSuggestions = [];
                                    showLotSuggestions = false;
                                  });
                                  FocusScope.of(context).unfocus();
                                },
                              );
                            },
                          ),
                        ),
                      ],
                      const SizedBox(height: 14),
                      TextFormField(
                        controller: quantityController,
                        keyboardType: const TextInputType.numberWithOptions(decimal: true),
                        decoration: const InputDecoration(
                          labelText: 'Cantidad',
                          prefixIcon: Icon(Icons.scale_rounded),
                        ),
                        validator: (value) {
                          if (value == null || value.trim().isEmpty) {
                            return 'Ingresa la cantidad.';
                          }
                          final parsed = double.tryParse(value.trim());
                          if (parsed == null || parsed <= 0) {
                            return 'Ingresa una cantidad valida.';
                          }
                          return null;
                        },
                      ),
                      if (errorText != null) ...[
                        const SizedBox(height: 14),
                        Text(
                          errorText!,
                          style: Theme.of(context).textTheme.bodyMedium?.copyWith(color: AppTokens.danger),
                        ),
                      ],
                      const SizedBox(height: 20),
                      FilledButton.icon(
                        onPressed: isSubmitting ? null : submit,
                        icon: isSubmitting
                            ? const SizedBox(
                                width: 18,
                                height: 18,
                                child: CircularProgressIndicator(strokeWidth: 2, color: Colors.white),
                              )
                            : const Icon(Icons.save_rounded),
                        label: Text(isSubmitting ? 'Guardando...' : 'Registrar movimiento'),
                      ),
                    ],
                  ),
                ),
              ),
            );
          },
        );
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: RefreshIndicator(
        onRefresh: _refresh,
        child: FutureBuilder<_InventoryBundle>(
          future: _future,
          builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.waiting) {
              return const AppLoader();
            }

            if (snapshot.hasError) {
              return ListView(
                padding: AppTokens.pagePadding,
                children: [
                  AppPanel(
                    title: 'Error al cargar inventario',
                    subtitle: snapshot.error.toString(),
                    child: FilledButton.icon(
                      onPressed: _refresh,
                      icon: const Icon(Icons.refresh_rounded),
                      label: const Text('Reintentar'),
                    ),
                  ),
                ],
              );
            }

            final bundle = snapshot.data;
            final stockResponse = bundle?.stock;
            final optionsResponse = bundle?.options;

            if (bundle == null ||
                stockResponse == null ||
                optionsResponse == null ||
                !stockResponse.success ||
                !optionsResponse.success) {
              return ListView(
                padding: AppTokens.pagePadding,
                children: [
                  AppPanel(
                    title: 'Inventario',
                    subtitle: stockResponse?.message ?? optionsResponse?.message ?? 'No se pudo cargar el módulo de inventario.',
                    child: FilledButton.icon(
                      onPressed: _refresh,
                      icon: const Icon(Icons.refresh_rounded),
                      label: const Text('Reintentar'),
                    ),
                  ),
                ],
              );
            }

            final options = optionsResponse.data ?? const <String, dynamic>{};
            final warehouses = List<Map<String, dynamic>>.from(options['warehouses'] as List? ?? const []);
            final transactions = List<Map<String, dynamic>>.from(options['transactions'] as List? ?? const []);
            final totalsRaw = stockResponse.meta['totals'];
            final totals = totalsRaw is Map
                ? Map<String, dynamic>.from(totalsRaw)
                : const <String, dynamic>{};
            // lowStock y noStock del TOTAL del inventario (vienen en meta.totals)
            final lowStockCount = _toDouble(totals['low_stock_count']).toInt();
            final noStockCount = _toDouble(totals['no_stock_count']).toInt();
            // Fallback: si el meta no trae los contadores, contar localmente
            final fallbackLow = _accumulatedItems.where((item) =>
                _toDouble(item['stock']) > 0 &&
                _toDouble(item['stock']) <= _toDouble(item['stock_min'])).length;
            final fallbackNo = _accumulatedItems
                .where((item) => _toDouble(item['stock']) <= 0)
                .length;
            final displayLow = lowStockCount > 0 ? lowStockCount : fallbackLow;
            final displayNo = noStockCount > 0 ? noStockCount : fallbackNo;
            final previewItems = _filteredItems();

            return ListView(
              controller: _scrollController,
              padding: AppTokens.pagePadding,
              children: [
                // Hero card minimalista: solo 2 KPIs
                AppHeroCard(
                  title: 'Inventario',
                  subtitle: 'Stock y valor del almacén',
                  child: Column(
                    children: [
                      Row(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Expanded(
                            child: _HeroMetric(
                              label: 'Stock',
                              value: '${totals['stock'] ?? 0} uds',
                              icon: Icons.inventory_2_rounded,
                            ),
                          ),
                          const SizedBox(width: 12),
                          Expanded(
                            child: _HeroMetric(
                              label: 'Valor',
                              value: _formatCurrency(totals['stock_cost_value']),
                              icon: Icons.account_balance_wallet_rounded,
                            ),
                          ),
                        ],
                      ),
                      const SizedBox(height: 14),
                      SizedBox(
                        width: double.infinity,
                        child: FilledButton.icon(
                          onPressed: () => _openMovementForm(warehouses: warehouses, transactions: transactions),
                          icon: const Icon(Icons.add_rounded),
                          label: const Text('Nuevo movimiento'),
                          style: FilledButton.styleFrom(
                            backgroundColor: Colors.white.withValues(alpha: 0.18),
                            foregroundColor: Colors.white,
                            padding: const EdgeInsets.symmetric(vertical: 12),
                          ),
                        ),
                      ),
                      const SizedBox(height: 10),
                      SizedBox(
                        width: double.infinity,
                        child: OutlinedButton.icon(
                          onPressed: () => context.push('/stocktake'),
                          icon: const Icon(Icons.fact_check_rounded),
                          label: const Text('Inventario manual'),
                          style: OutlinedButton.styleFrom(
                            foregroundColor: Colors.white,
                            side: BorderSide(color: Colors.white.withValues(alpha: 0.55)),
                            padding: const EdgeInsets.symmetric(vertical: 12),
                          ),
                        ),
                      ),
                    ],
                  ),
                ),
                // Chips de alerta — tap para filtrar la lista
                if (displayLow > 0 || displayNo > 0) ...[
                  const SizedBox(height: 14),
                  Row(
                    children: [
                      if (displayNo > 0)
                        Expanded(
                          child: _AlertChip(
                            icon: Icons.remove_shopping_cart_rounded,
                            label: '$displayNo agotados',
                            color: AppTokens.danger,
                            active: _activeFilter == _StockFilter.outOfStock,
                            onTap: () => _toggleFilter(_StockFilter.outOfStock),
                          ),
                        ),
                      if (displayNo > 0 && displayLow > 0) const SizedBox(width: 10),
                      if (displayLow > 0)
                        Expanded(
                          child: _AlertChip(
                            icon: Icons.warning_amber_rounded,
                            label: '$displayLow bajo stock',
                            color: AppTokens.warning,
                            active: _activeFilter == _StockFilter.lowStock,
                            onTap: () => _toggleFilter(_StockFilter.lowStock),
                          ),
                        ),
                    ],
                  ),
                  if (_activeFilter != _StockFilter.all) ...[
                    const SizedBox(height: 8),
                    Align(
                      alignment: Alignment.centerRight,
                      child: TextButton.icon(
                        onPressed: () => _toggleFilter(_activeFilter),
                        icon: const Icon(Icons.close_rounded, size: 16),
                        label: const Text('Quitar filtro'),
                      ),
                    ),
                  ],
                ] else ...[
                  const SizedBox(height: 14),
                  const _AlertChip(
                    icon: Icons.check_circle_rounded,
                    label: 'Inventario saludable',
                    color: AppTokens.success,
                  ),
                ],
                const SizedBox(height: 20),
                // Lista de productos
                AppPanel(
                  title: _activeFilter == _StockFilter.outOfStock
                      ? 'Productos agotados'
                      : _activeFilter == _StockFilter.lowStock
                          ? 'Productos bajo stock'
                          : 'Productos',
                  subtitle: 'Toca un producto para ver su detalle.',
                  trailing: Text(
                    '${previewItems.length}',
                    style: Theme.of(context).textTheme.titleMedium?.copyWith(
                          color: AppTokens.primary,
                          fontWeight: FontWeight.w700,
                        ),
                  ),
                  child: previewItems.isEmpty
                      ? EmptyStatePanel(
                          icon: Icons.inventory_2_rounded,
                          title: _activeFilter != _StockFilter.all
                              ? 'Sin productos en este filtro'
                              : 'Sin inventario visible',
                          subtitle: _activeFilter != _StockFilter.all
                              ? 'Quita el filtro para ver todos los productos.'
                              : 'No se encontraron productos para el almacén del usuario.',
                        )
                      : Column(
                          crossAxisAlignment: CrossAxisAlignment.stretch,
                          children: [
                            for (final item in previewItems) ...[
                              _InventoryItemRow(
                                item: item,
                                onMove: () => _openMovementForm(
                                  warehouses: warehouses,
                                  transactions: transactions,
                                  preSelectedItem: item,
                                ),
                                onDetail: () => _showItemDetailSheet(item),
                              ),
                              if (item != previewItems.last) const Divider(height: 20),
                            ],
                          ],
                        ),
                ),
                // Botón "Cargar más" (solo si no hay filtro activo y hay más páginas)
                if (_activeFilter == _StockFilter.all && _hasMore) ...[
                  const SizedBox(height: 14),
                  Center(
                    child: OutlinedButton.icon(
                      onPressed: _isLoadingMore ? null : _loadMore,
                      icon: _isLoadingMore
                          ? const SizedBox(
                              width: 16,
                              height: 16,
                              child: CircularProgressIndicator(strokeWidth: 2),
                            )
                          : const Icon(Icons.expand_more_rounded),
                      label: Text(_isLoadingMore ? 'Cargando...' : 'Cargar más productos'),
                    ),
                  ),
                ],
                if (_activeFilter == _StockFilter.all && !_hasMore && _accumulatedItems.isNotEmpty) ...[
                  const SizedBox(height: 14),
                  Center(
                    child: Text(
                      'No hay más productos',
                      style: Theme.of(context).textTheme.bodySmall?.copyWith(
                            color: AppTokens.secondary,
                          ),
                    ),
                  ),
                ],
              ],
            );
          },
        ),
      ),
    );
  }

  double _toDouble(Object? value) => double.tryParse('$value') ?? 0;

}

class _InventoryBundle {
  const _InventoryBundle({
    required this.stock,
    required this.options,
  });

  final MobileApiResponse<List<Map<String, dynamic>>> stock;
  final MobileApiResponse<Map<String, dynamic>> options;
}

class _InventoryItemRow extends StatelessWidget {
  const _InventoryItemRow({
    required this.item,
    required this.onMove,
    required this.onDetail,
  });

  final Map<String, dynamic> item;
  final VoidCallback onMove;
  final VoidCallback onDetail;

  @override
  Widget build(BuildContext context) {
    final stock = double.tryParse('${item['stock']}') ?? 0;
    final stockMin = double.tryParse('${item['stock_min']}') ?? 0;
    final riskColor = stock <= 0
        ? AppTokens.danger
        : stock <= stockMin
            ? AppTokens.warning
            : AppTokens.success;

    return InkWell(
      onTap: onDetail,
      borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
      child: Padding(
        padding: const EdgeInsets.symmetric(vertical: 4),
        child: Row(
          crossAxisAlignment: CrossAxisAlignment.center,
          children: [
            CircleAvatar(
              backgroundColor: riskColor.withValues(alpha: 0.12),
              foregroundColor: riskColor,
              child: const Icon(Icons.medication_liquid_rounded, size: 18),
            ),
            const SizedBox(width: 12),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    item['description']?.toString() ?? 'Producto',
                    maxLines: 2,
                    overflow: TextOverflow.ellipsis,
                    style: Theme.of(context).textTheme.titleSmall,
                  ),
                  const SizedBox(height: 4),
                  Row(
                    children: [
                      Icon(Icons.inventory_2_outlined, size: 13, color: riskColor),
                      const SizedBox(width: 4),
                      Text(
                        'Stock ${item['stock'] ?? 0}',
                        style: Theme.of(context).textTheme.bodySmall?.copyWith(
                              color: riskColor,
                              fontWeight: FontWeight.w600,
                            ),
                      ),
                      Text(
                        ' · Min ${item['stock_min'] ?? 0}',
                        style: Theme.of(context).textTheme.bodySmall?.copyWith(
                              color: AppTokens.secondary,
                            ),
                      ),
                    ],
                  ),
                ],
              ),
            ),
            const SizedBox(width: 8),
            FilledButton.tonalIcon(
              onPressed: onMove,
              icon: const Icon(Icons.swap_horiz_rounded, size: 18),
              label: const Text('Mover'),
              style: FilledButton.styleFrom(
                backgroundColor: AppTokens.primary.withValues(alpha: 0.12),
                foregroundColor: AppTokens.primary,
                padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 8),
                minimumSize: const Size(0, 36),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _HeroMetric extends StatelessWidget {
  const _HeroMetric({
    required this.label,
    required this.value,
    required this.icon,
  });

  final String label;
  final String value;
  final IconData icon;

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: Colors.white.withValues(alpha: 0.10),
        borderRadius: BorderRadius.circular(AppTokens.radiusMedium),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        mainAxisSize: MainAxisSize.min,
        children: [
          Icon(icon, size: 18, color: Colors.white),
          const SizedBox(height: 10),
          Text(
            value,
            maxLines: 1,
            overflow: TextOverflow.ellipsis,
            style: Theme.of(context).textTheme.titleMedium?.copyWith(
                  color: Colors.white,
                  fontWeight: FontWeight.w700,
                ),
          ),
          const SizedBox(height: 4),
          Text(
            label,
            maxLines: 1,
            overflow: TextOverflow.ellipsis,
            style: Theme.of(context).textTheme.bodySmall?.copyWith(
                  color: Colors.white.withValues(alpha: 0.84),
                ),
          ),
        ],
      ),
    );
  }
}

class _AlertChip extends StatelessWidget {
  const _AlertChip({
    required this.icon,
    required this.label,
    required this.color,
    this.onTap,
    this.active = false,
  });

  final IconData icon;
  final String label;
  final Color color;
  final VoidCallback? onTap;
  final bool active;

  @override
  Widget build(BuildContext context) {
    final bgAlpha = active ? 0.22 : 0.10;
    final borderAlpha = active ? 0.60 : 0.30;

    return Material(
      color: Colors.transparent,
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
        child: Container(
          padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 12),
          decoration: BoxDecoration(
            color: color.withValues(alpha: bgAlpha),
            borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
            border: Border.all(
              color: color.withValues(alpha: borderAlpha),
              width: active ? 1.5 : 1,
            ),
          ),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Icon(
                active ? Icons.filter_alt_rounded : icon,
                size: 18,
                color: color,
              ),
              const SizedBox(width: 8),
              Flexible(
                child: Text(
                  label,
                  overflow: TextOverflow.ellipsis,
                  style: Theme.of(context).textTheme.labelLarge?.copyWith(
                        color: color,
                        fontWeight: FontWeight.w700,
                      ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _DetailRow extends StatelessWidget {
  const _DetailRow({
    required this.icon,
    required this.label,
    required this.value,
    this.color,
  });

  final IconData icon;
  final String label;
  final String value;
  final Color? color;

  @override
  Widget build(BuildContext context) {
    final effectiveColor = color ?? AppTokens.textPrimary;
    return Row(
      children: [
        Icon(icon, size: 20, color: effectiveColor),
        const SizedBox(width: 12),
        Expanded(
          child: Text(
            label,
            style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                  color: AppTokens.secondary,
                ),
          ),
        ),
        Text(
          value,
          style: Theme.of(context).textTheme.titleSmall?.copyWith(
                color: effectiveColor,
                fontWeight: FontWeight.w700,
              ),
        ),
      ],
    );
  }
}