import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../../core/utils/shared_provider.dart';
import '../pdf_export/pdf_service.dart';
import 'calculator_provider.dart';
import '../../widgets/custom_button.dart';
import '../converter/converter_provider.dart';
import '../splitter/splitter_provider.dart';

class MainNavigationScreen extends ConsumerStatefulWidget {
  const MainNavigationScreen({super.key});
  @override
  ConsumerState<MainNavigationScreen> createState() => _MainNavigationScreenState();
}

class _MainNavigationScreenState extends ConsumerState<MainNavigationScreen> {
  int _selectedIndex = 0;

  @override
  Widget build(BuildContext context) {
    final currentVal = ref.watch(sharedValueProvider);
    final calcState = ref.watch(calculatorProvider);
    final history = ref.watch(historyProvider);

    return Scaffold(
      backgroundColor: Colors.white,
      appBar: AppBar(
        title: const Text("Quote", style: TextStyle(fontWeight: FontWeight.bold)),
        centerTitle: true,
        actions: [
          IconButton(
            icon: const Icon(Icons.picture_as_pdf_rounded),
            onPressed: () {
              PdfService.generateSplitterReport(
                currentVal,
                ref.read(splitterProvider).friends,
                ref.read(splitterProvider.notifier).calculateSettlements(currentVal),
                history,
              );
            },
          )
        ],
      ),
      body: Column(
        children: [
          Container(
            width: double.infinity,
            padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
            decoration: BoxDecoration(
              color: Colors.deepPurple.withOpacity(0.05),
              border: Border(bottom: BorderSide(color: Colors.deepPurple.withOpacity(0.1))),
            ),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.end,
              children: [
                Text(
                    _selectedIndex == 2 ? "LA TUA SPESA ATTUALE" : "VALORE ATTIVO",
                    style: const TextStyle(fontSize: 10, fontWeight: FontWeight.bold, color: Colors.deepPurple)
                ),
                FittedBox(
                  fit: BoxFit.scaleDown,
                  child: Text(
                    _selectedIndex == 0
                        ? calcState.equation.replaceAll('.', ',')
                        : currentVal.toStringAsFixed(2).replaceAll('.', ','),
                    style: const TextStyle(fontSize: 48, fontWeight: FontWeight.w900, color: Colors.black87),
                  ),
                ),
              ],
            ),
          ),
          Expanded(
            child: IndexedStack(
              index: _selectedIndex,
              children: [
                CalculatorModule(),
                ConverterModule(),
                SplitterModule(),
              ],
            ),
          ),
        ],
      ),
      bottomNavigationBar: NavigationBar(
        selectedIndex: _selectedIndex,
        onDestinationSelected: (index) => setState(() => _selectedIndex = index),
        destinations: const [
          NavigationDestination(icon: Icon(Icons.calculate_outlined), label: 'Calcola'),
          NavigationDestination(icon: Icon(Icons.currency_exchange_outlined), label: 'Converti'),
          NavigationDestination(icon: Icon(Icons.group_outlined), label: 'Dividi'),
        ],
      ),
    );
  }
}

class CalculatorModule extends ConsumerWidget {
  const CalculatorModule({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final calcLogic = ref.read(calculatorProvider.notifier);

    // Layout richiesto:
    // Riga 1: C | ⌫ | % | ÷
    // Riga 2: 7 | 8 | 9 | ×
    // Riga 3: 4 | 5 | 6 | -
    // Riga 4: 1 | 2 | 3 | +
    // Riga 5: ± | 0 | , | =

    final List<String> labels = [
      'C', '⌫', '%', '÷',
      '7', '8', '9', '×',
      '4', '5', '6', '-',
      '1', '2', '3', '+',
      '±', '0', ',', '='
    ];

    return Padding(
      padding: const EdgeInsets.all(12),
      child: GridView.builder(
        // Usiamo 4 colonne
        gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
          crossAxisCount: 4,
          mainAxisSpacing: 12,
          crossAxisSpacing: 12,
        ),
        itemCount: labels.length,
        itemBuilder: (context, index) {
          final label = labels[index];

          // --- LOGICA COLORI ---
          Color? bgColor;
          Color textColor = Colors.black87;

          if (RegExp(r'[0-9]').hasMatch(label) || label == ',') {
            // Numeri e virgola: Arancione Chiaro
            bgColor = const Color(0xFFFFCC80);
          } else if (['÷', '×', '-', '+', '=', '%'].contains(label)) {
            // Segni e Uguale: Azzurro
            bgColor = const Color(0xFF81D4FA);
            if (label == '=') bgColor = const Color(0xFF4FC3F7); // Azzurro più scuro per l'uguale
          } else if (label == 'C' || label == '⌫') {
            // Comandi di cancellazione: Rosso chiaro per distinguerli
            bgColor = const Color(0xFFFFCDD2);
            textColor = const Color(0xFFB71C1C);
          } else if (label == '±') {
            // Segno +/-: Grigio neutro
            bgColor = Colors.grey[300];
          }

          return CustomButton(
            label: label,
            onPressed: () => calcLogic.onBtnPressed(label),
            color: bgColor,
            textColor: textColor,
          );
        },
      ),
    );
  }
}

class ConverterModule extends StatelessWidget {
  @override
  Widget build(BuildContext context) => const Center(child: Text("Modulo Convertitore pronto"));
}

class SplitterModule extends ConsumerStatefulWidget {
  const SplitterModule({super.key});
  @override
  ConsumerState<SplitterModule> createState() => _SplitterModuleState();
}

class _SplitterModuleState extends ConsumerState<SplitterModule> {
  final TextEditingController _nameController = TextEditingController();
  final TextEditingController _amountController = TextEditingController();
  final TextEditingController _noteController = TextEditingController();

  void _showHistoryDetails(BuildContext context, WidgetRef ref) {
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      shape: const RoundedRectangleBorder(borderRadius: BorderRadius.vertical(top: Radius.circular(25))),
      builder: (context) {
        return Consumer(builder: (context, ref, _) {
          final history = ref.watch(historyProvider);
          final historyLogic = ref.read(historyProvider.notifier);

          return Padding(
            padding: EdgeInsets.only(
                bottom: MediaQuery.of(context).viewInsets.bottom,
                left: 20, right: 20, top: 20
            ),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                const Text("Dettaglio tua spesa", style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
                const Text("Aggiungi una nota per ogni importo", style: TextStyle(fontSize: 12, color: Colors.grey)),
                const SizedBox(height: 15),
                if (history.isEmpty)
                  const Padding(padding: EdgeInsets.all(20), child: Text("Nessun dato in calcolatrice")),
                ConstrainedBox(
                  constraints: BoxConstraints(maxHeight: MediaQuery.of(context).size.height * 0.4),
                  child: ListView.builder(
                    shrinkWrap: true,
                    itemCount: history.length,
                    itemBuilder: (context, idx) {
                      return Padding(
                        padding: const EdgeInsets.symmetric(vertical: 8),
                        child: Row(
                          children: [
                            Text("${history[idx].result} €", style: const TextStyle(fontWeight: FontWeight.bold)),
                            const SizedBox(width: 15),
                            Expanded(
                              child: TextField(
                                decoration: const InputDecoration(hintText: "Nota...", isDense: true),
                                controller: TextEditingController.fromValue(
                                  TextEditingValue(
                                    text: history[idx].note,
                                    selection: TextSelection.collapsed(offset: history[idx].note.length),
                                  ),
                                ),
                                onChanged: (val) => historyLogic.updateNote(idx, val),
                              ),
                            ),
                          ],
                        ),
                      );
                    },
                  ),
                ),
                const SizedBox(height: 20),
                ElevatedButton(
                    style: ElevatedButton.styleFrom(minimumSize: const Size(double.infinity, 50)),
                    onPressed: () => Navigator.pop(context),
                    child: const Text("Salva e Chiudi")
                ),
                const SizedBox(height: 20),
              ],
            ),
          );
        });
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    final mySpent = ref.watch(sharedValueProvider);
    final splitter = ref.watch(splitterProvider);
    final history = ref.watch(historyProvider);
    final logic = ref.read(splitterProvider.notifier);

    return Column(
      children: [
        Padding(
          padding: const EdgeInsets.all(12.0),
          child: Column(
            children: [
              Row(
                children: [
                  Expanded(flex: 2, child: TextField(controller: _nameController, decoration: const InputDecoration(labelText: "Amico", isDense: true, border: OutlineInputBorder()))),
                  const SizedBox(width: 5),
                  Expanded(flex: 1, child: TextField(controller: _amountController, keyboardType: TextInputType.number, decoration: const InputDecoration(labelText: "€", isDense: true, border: OutlineInputBorder()))),
                  const SizedBox(width: 5),
                  Expanded(flex: 2, child: TextField(controller: _noteController, decoration: const InputDecoration(labelText: "Nota", isDense: true, border: OutlineInputBorder()))),
                  const SizedBox(width: 5),
                  IconButton.filled(
                    onPressed: () {
                      if (_nameController.text.isNotEmpty) {
                        double amount = double.tryParse(_amountController.text.replaceAll(',', '.')) ?? 0.0;
                        logic.addFriend(_nameController.text, amount, _noteController.text);
                        _nameController.clear(); _amountController.clear(); _noteController.clear();
                        FocusScope.of(context).unfocus();
                      }
                    },
                    icon: const Icon(Icons.add),
                  ),
                ],
              ),
            ],
          ),
        ),
        Expanded(
          child: Container(
            margin: const EdgeInsets.symmetric(horizontal: 12),
            decoration: BoxDecoration(color: Colors.grey[50], borderRadius: const BorderRadius.vertical(top: Radius.circular(20))),
            child: CustomScrollView(
              slivers: [
                SliverToBoxAdapter(
                  child: Card(
                    elevation: 0,
                    color: Colors.deepPurple.withOpacity(0.05),
                    margin: const EdgeInsets.all(12),
                    child: InkWell(
                      onTap: () => _showHistoryDetails(context, ref),
                      borderRadius: BorderRadius.circular(12),
                      child: ListTile(
                        dense: true,
                        leading: const CircleAvatar(radius: 15, child: Icon(Icons.receipt_long, size: 16)),
                        title: const Text("Il Tuo Anticipo Totale", style: TextStyle(fontWeight: FontWeight.bold, color: Colors.deepPurple)),
                        subtitle: Text("Clicca per i singoli calcoli (${history.length})"),
                        trailing: Text("${mySpent.toStringAsFixed(2)} €", style: const TextStyle(fontWeight: FontWeight.bold, color: Colors.deepPurple, fontSize: 18)),
                      ),
                    ),
                  ),
                ),
                SliverList(
                  delegate: SliverChildBuilderDelegate(
                        (context, index) {
                      final friend = splitter.friends[index];
                      return ListTile(
                        dense: true,
                        title: Text(friend.name, style: const TextStyle(fontWeight: FontWeight.w600)),
                        subtitle: Text(friend.note.isEmpty ? "Anticipo spesa" : friend.note),
                        trailing: Row(
                          mainAxisSize: MainAxisSize.min,
                          children: [
                            Text("${friend.spent.toStringAsFixed(2)} €"),
                            IconButton(icon: const Icon(Icons.remove_circle_outline, color: Colors.red, size: 18), onPressed: () => logic.removeFriend(index)),
                          ],
                        ),
                      );
                    },
                    childCount: splitter.friends.length,
                  ),
                ),
                const SliverToBoxAdapter(child: SizedBox(height: 100)),
              ],
            ),
          ),
        ),
        Container(
          padding: const EdgeInsets.all(20),
          decoration: BoxDecoration(
            color: Colors.white,
            boxShadow: [BoxShadow(color: Colors.black.withOpacity(0.05), blurRadius: 10, offset: const Offset(0, -5))],
            borderRadius: const BorderRadius.vertical(top: Radius.circular(30)),
          ),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: logic.calculateSettlements(mySpent).map((text) =>
                Padding(padding: const EdgeInsets.symmetric(vertical: 2), child: Text(text, textAlign: TextAlign.center, style: TextStyle(
                  fontWeight: text.contains('➔') ? FontWeight.bold : FontWeight.normal,
                  color: text.contains('➔') ? Colors.deepPurple : Colors.black87,
                  fontSize: text.contains('➔') ? 16 : 13,
                )))
            ).toList(),
          ),
        ),
      ],
    );
  }
}