import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:fl_chart/fl_chart.dart';
import 'package:provider/provider.dart';

import '../models/transaction.dart';
import '../models/budget.dart';
import '../services/hive_service.dart';
import '../services/i18n_service.dart';

class StatisticsScreen extends StatefulWidget {
  const StatisticsScreen({super.key});

  @override
  State<StatisticsScreen> createState() => _StatisticsScreenState();
}

class _StatisticsScreenState extends State<StatisticsScreen> {
  List<Transaction> _transactions = [];
  double _totalExpenses = 0.0;
  double _totalIncome = 0.0;
  Map<TransactionCategory, double> _expensesByCategory = {};

  List<Budget> _budgets = [];
  final Map<int, double> _budgetSpent = {};

  int _selectedMonth = DateTime.now().month;
  int _selectedYear = DateTime.now().year;

  String _currentCurrency = 'Kz';
  late HiveService _hiveService;

  @override
  void initState() {
    super.initState();
    _hiveService = HiveService();
    _loadCurrency();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _loadDataForPeriod();
    });
  }

  Future<void> _loadCurrency() async {
    final prefs = await SharedPreferences.getInstance();
    setState(() {
      _currentCurrency = prefs.getString('currencySymbol') ?? 'Kz';
    });
  }

  Future<void> _loadDataForPeriod() async {
    final allTransactions = await _hiveService.getTransactions();
    final allBudgets = await _hiveService.getBudgets();

    // Filtrar transações do mês/ano selecionado
    final fetchedTransactions = allTransactions.where((t) =>
      t.date.year == _selectedYear && t.date.month == _selectedMonth
    ).toList();

    double expenses = 0.0;
    double income = 0.0;
    for (var t in fetchedTransactions) {
      if (t.type == TransactionType.expense) {
        expenses += t.amount;
      } else {
        income += t.amount;
      }
    }

    // Calcular despesas por categoria
    final Map<TransactionCategory, double> expensesByCategoryTemp = {};
    for (var t in fetchedTransactions) {
      if (t.type == TransactionType.expense) {
        expensesByCategoryTemp.update(
          t.category,
          (value) => value + t.amount,
          ifAbsent: () => t.amount,
        );
      }
    }

    // Calcular gastos por orçamento
    final Map<int, double> budgetSpentTemp = {};
    for (var i = 0; i < allBudgets.length; i++) {
      final budget = allBudgets[i];
      if (_isBudgetInSelectedPeriod(budget)) {
        final spentAmount = _getSpentAmountForBudget(budget, fetchedTransactions);
        budgetSpentTemp[i] = spentAmount;
      }
    }

    if (mounted) {
      setState(() {
        _transactions = fetchedTransactions;
        _totalExpenses = expenses;
        _totalIncome = income;
        _expensesByCategory = expensesByCategoryTemp;
        _budgets = allBudgets.where((b) => _isBudgetInSelectedPeriod(b)).toList();
        _budgetSpent.clear();
        _budgetSpent.addAll(budgetSpentTemp);
      });
    }
  }

  bool _isBudgetInSelectedPeriod(Budget budget) {
    final startOfSelectedMonth = DateTime(_selectedYear, _selectedMonth, 1);
    final endOfSelectedMonth = DateTime(_selectedYear, _selectedMonth + 1, 0);
    final isOverlapping = budget.startDate.isBefore(endOfSelectedMonth.add(const Duration(days: 1))) &&
                        budget.endDate.isAfter(startOfSelectedMonth.subtract(const Duration(days: 1)));
    return isOverlapping;
  }

  double _getSpentAmountForBudget(Budget budget, List<Transaction> transactions) {
    final relevantTransactions = transactions.where((t) {
      final isCategoryMatch = t.category == budget.category;
      final isDateMatch = t.date.isAfter(budget.startDate.subtract(const Duration(days: 1))) &&
                          t.date.isBefore(budget.endDate.add(const Duration(days: 1)));
      return isCategoryMatch && isDateMatch && t.type == TransactionType.expense;
    }).toList();
    return relevantTransactions.fold<double>(0.0, (sum, item) => sum + item.amount);
  }

  String _getMonthName(int month, String languageCode) {
    return DateFormat.MMMM(languageCode).format(DateTime(_selectedYear, month));
  }

  String _getCategoryName(TransactionCategory category, I18nService i18n) {
    return {
      TransactionCategory.food: i18n.t('food'),
      TransactionCategory.transport: i18n.t('transport'),
      TransactionCategory.social: i18n.t('social'),
      TransactionCategory.education: i18n.t('education'),
      TransactionCategory.medical: i18n.t('medical'),
      TransactionCategory.shopping: i18n.t('shopping'),
      TransactionCategory.salary: i18n.t('salary'),
      TransactionCategory.invest: i18n.t('invest'),
      TransactionCategory.business: i18n.t('business'),
      TransactionCategory.others: i18n.t('others'),
    }[category] ?? i18n.t('unknown');
  }

  IconData _getCategoryIcon(TransactionCategory category) {
    switch (category) {
      case TransactionCategory.food: return Icons.fastfood;
      case TransactionCategory.transport: return Icons.directions_car;
      case TransactionCategory.social: return Icons.group;
      case TransactionCategory.education: return Icons.school;
      case TransactionCategory.medical: return Icons.medical_services;
      case TransactionCategory.shopping: return Icons.shopping_bag;
      case TransactionCategory.salary: return Icons.attach_money;
      case TransactionCategory.invest: return Icons.trending_up;
      case TransactionCategory.business: return Icons.business_center;
      case TransactionCategory.others: return Icons.category;
      case TransactionCategory.house: return Icons.home;
      case TransactionCategory.utilities: return Icons.lightbulb;
      case TransactionCategory.subscriptions: return Icons.subscriptions;
      case TransactionCategory.leisure: return Icons.movie;
      case TransactionCategory.gym: return Icons.fitness_center;
      case TransactionCategory.gifts: return Icons.card_giftcard;
      case TransactionCategory.pets: return Icons.pets;
      case TransactionCategory.freelance: return Icons.work;
      case TransactionCategory.dividends: return Icons.monetization_on;
      case TransactionCategory.loan: return Icons.account_balance;
      case TransactionCategory.refund: return Icons.reply;
      case TransactionCategory.tax: return Icons.account_balance_wallet;
      case TransactionCategory.bonus: return Icons.star;
      case TransactionCategory.allowance: return Icons.money_off;
      case TransactionCategory.pension: return Icons.elderly;
      case TransactionCategory.scholarship: return Icons.school;
      case TransactionCategory.grant: return Icons.card_giftcard;
    }
  }

  Widget _buildSummaryCard(I18nService i18n) {
    return Card(
      color: const Color(0xFF23204A),
      elevation: 6,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
      margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      child: Padding(
        padding: const EdgeInsets.all(20.0),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: [
            _buildSummaryItem(
              title: i18n.t('income'),
              amount: _totalIncome,
              color: Colors.greenAccent,
              icon: Icons.arrow_upward,
              i18n: i18n,
            ),
            _buildSummaryItem(
              title: i18n.t('expenses'),
              amount: _totalExpenses,
              color: Colors.redAccent,
              icon: Icons.arrow_downward,
              i18n: i18n,
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildSummaryItem({
    required String title,
    required double amount,
    required Color color,
    required IconData icon,
    required I18nService i18n,
  }) {
    return Column(
      children: [
        CircleAvatar(
          backgroundColor: color.withOpacity(0.1),
          child: Icon(icon, color: color),
        ),
        const SizedBox(height: 8),
        Text(
          title,
          style: const TextStyle(color: Colors.white70, fontSize: 14),
        ),
        const SizedBox(height: 4),
        Text(
          '$_currentCurrency ${amount.toStringAsFixed(2)}',
          style: TextStyle(
            color: color,
            fontWeight: FontWeight.bold,
            fontSize: 20,
          ),
        ),
      ],
    );
  }

  Widget _buildPeriodSelector(I18nService i18n) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          _buildDropdown(
            label: i18n.t('month'),
            value: _selectedMonth,
            items: List.generate(12, (i) => i + 1).map((m) => DropdownMenuItem(
              value: m,
              child: Text(DateFormat.MMMM(i18n.locale.languageCode).format(DateTime(0, m))),
            )).toList(),
            onChanged: (v) {
              if (v != null) {
                setState(() {
                  _selectedMonth = v;
                  _loadDataForPeriod();
                });
              }
            },
            i18n: i18n,
          ),
          _buildDropdown(
            label: i18n.t('year'),
            value: _selectedYear,
            items: List.generate(5, (i) => DateTime.now().year - i).map((y) => DropdownMenuItem(
              value: y,
              child: Text(y.toString()),
            )).toList(),
            onChanged: (v) {
              if (v != null) {
                setState(() {
                  _selectedYear = v;
                  _loadDataForPeriod();
                });
              }
            },
            i18n: i18n,
          ),
        ],
      ),
    );
  }

  Widget _buildDropdown({
    required String label,
    required int value,
    required List<DropdownMenuItem<int>> items,
    required ValueChanged<int?> onChanged,
    required I18nService i18n,
  }) {
    return Expanded(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(label, style: const TextStyle(color: Colors.white70, fontSize: 12)),
          const SizedBox(height: 4),
          Container(
            padding: const EdgeInsets.symmetric(horizontal: 12),
            decoration: BoxDecoration(
              color: const Color(0xFF23204A),
              borderRadius: BorderRadius.circular(12),
            ),
            child: DropdownButtonHideUnderline(
              child: DropdownButton<int>(
                isExpanded: true,
                value: value,
                dropdownColor: const Color(0xFF23204A),
                icon: const Icon(Icons.arrow_drop_down, color: Colors.white),
                style: const TextStyle(color: Colors.white, fontSize: 16),
                items: items,
                onChanged: onChanged,
              ),
            ),
          ),
        ],
      ),
    );
  }
  
  // Refatorando a lista de estatísticas extras
  Widget _buildExtraStatsList(I18nService i18n) {
    if (_transactions.isEmpty) return Container();
    
    final biggestExpense = _transactions
        .where((t) => t.type == TransactionType.expense)
        .fold<Transaction?>(null, (prev, t) => prev == null || t.amount > prev.amount ? t : prev);
    final mostUsedCategory = _expensesByCategory.entries.isEmpty
        ? null
        : _expensesByCategory.entries.reduce((a, b) => a.value > b.value ? a : b).key;
    final avgExpense = _transactions
        .where((t) => t.type == TransactionType.expense)
        .fold<double>(0.0, (sum, t) => sum + t.amount) /
        (_transactions.where((t) => t.type == TransactionType.expense).length == 0 ? 1 : _transactions.where((t) => t.type == TransactionType.expense).length);

    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 8.0),
      child: Column(
        children: [
          _buildStatListItem(
            icon: Icons.trending_down,
            color: Colors.redAccent,
            title: i18n.t('biggest_expense'),
            value: biggestExpense != null
                ? '${_currentCurrency} ${biggestExpense.amount.toStringAsFixed(2)}'
                : '--',
            subtitle: biggestExpense != null
                ? biggestExpense.title
                : i18n.t('no_data'),
          ),
          _buildStatListItem(
            icon: Icons.category,
            color: Colors.blueAccent,
            title: i18n.t('most_used_category'),
            value: mostUsedCategory != null
                ? _getCategoryName(mostUsedCategory, i18n)
                : '--',
            subtitle: '',
          ),
          _buildStatListItem(
            icon: Icons.calculate,
            color: Colors.orangeAccent,
            title: i18n.t('avg_expense'),
            value: '${_currentCurrency} ${avgExpense.isNaN ? '0.00' : avgExpense.toStringAsFixed(2)}',
            subtitle: '',
          ),
          _buildStatListItem(
            icon: Icons.list,
            color: Colors.purpleAccent,
            title: i18n.t('total_transactions'),
            value: _transactions.length.toString(),
            subtitle: '',
          ),
        ],
      ),
    );
  }

  Widget _buildStatListItem({
    required IconData icon,
    required Color color,
    required String title,
    required String value,
    required String subtitle,
  }) {
    return Card(
      elevation: 3,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(14)),
      color: const Color(0xFF23204A),
      margin: const EdgeInsets.only(bottom: 12),
      child: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Row(
          children: [
            CircleAvatar(
              backgroundColor: color.withOpacity(0.15),
              child: Icon(icon, color: color),
            ),
            const SizedBox(width: 16),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(title, style: const TextStyle(fontWeight: FontWeight.bold, color: Colors.white70)),
                  const SizedBox(height: 4),
                  Text(value, style: TextStyle(fontWeight: FontWeight.bold, fontSize: 18, color: color)),
                ],
              ),
            ),
            if (subtitle.isNotEmpty)
              Text(subtitle, style: const TextStyle(fontSize: 12, color: Colors.white54)),
          ],
        ),
      ),
    );
  }

  // Gráfico de linha para evolução do saldo
  Widget _buildBalanceLineChart(I18nService i18n) {
    if (_transactions.isEmpty) return Container();
    final sorted = List.of(_transactions)..sort((a, b) => a.date.compareTo(b.date));
    double running = 0;
    final List<FlSpot> saldoSpots = [];
    for (int i = 0; i < sorted.length; i++) {
      running += sorted[i].type == TransactionType.income ? sorted[i].amount : -sorted[i].amount;
      saldoSpots.add(FlSpot(i.toDouble(), running));
    }
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 8.0),
      child: Card(
        elevation: 4,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
        color: const Color(0xFF23204A),
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(i18n.t('balance_evolution'), style: const TextStyle(fontSize: 20, fontWeight: FontWeight.bold, color: Colors.white)),
              const SizedBox(height: 12),
              SizedBox(
                height: 180,
                child: LineChart(
                  LineChartData(
                    lineBarsData: [
                      LineChartBarData(
                        spots: saldoSpots,
                        isCurved: true,
                        color: Colors.blueAccent,
                        barWidth: 3,
                        dotData: FlDotData(show: false),
                      ),
                    ],
                    titlesData: FlTitlesData(show: false),
                    gridData: FlGridData(show: false),
                    borderData: FlBorderData(show: false),
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  // Gráfico de pizza bonito e responsivo
  Widget _buildBeautifulPieChart(I18nService i18n) {
    if (_expensesByCategory.isEmpty) {
      return Container();
    }

    final totalExpenses = _expensesByCategory.values.fold(0.0, (sum, amount) => sum + amount);
    final List<Color> colors = [
      Colors.blueAccent, Colors.redAccent, Colors.greenAccent, Colors.purpleAccent,
      Colors.orangeAccent, Colors.teal, Colors.brown, Colors.pinkAccent, Colors.amber, Colors.cyan
    ];
    int colorIndex = 0;

    // Responsividade
    final double chartSize = MediaQuery.of(context).size.width * 0.7;

    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 8.0),
      child: Card(
        elevation: 6,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20)),
        color: const Color(0xFF23204A),
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.center,
            children: [
              Text(
                i18n.t('expenses_by_category'),
                style: const TextStyle(fontSize: 22, fontWeight: FontWeight.bold, color: Colors.white),
              ),
              SizedBox(
                height: chartSize,
                width: chartSize,
                child: PieChart(
                  PieChartData(
                    sections: _expensesByCategory.entries.map((entry) {
                      final percentage = (entry.value / totalExpenses) * 100;
                      final categoryName = _getCategoryName(entry.key, i18n);
                      final color = colors[colorIndex++ % colors.length];
                      return PieChartSectionData(
                        color: color,
                        value: entry.value,
                        title: '${percentage.toStringAsFixed(1)}%',
                        radius: chartSize / 3,
                        titleStyle: const TextStyle(
                          fontSize: 16,
                          fontWeight: FontWeight.bold,
                          color: Colors.white,
                          shadows: [Shadow(color: Colors.black45, blurRadius: 2)],
                        ),
                        badgeWidget: _buildCategoryBadge(entry.key, color, i18n),
                        badgePositionPercentageOffset: 1.15,
                      );
                    }).toList(),
                    sectionsSpace: 3,
                    centerSpaceRadius: chartSize / 6,
                  ),
                ),
              ),
              const SizedBox(height: 16),
              _buildLegend(colors, i18n),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildCategoryBadge(TransactionCategory category, Color color, I18nService i18n) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
      decoration: BoxDecoration(
        color: color.withOpacity(0.85),
        borderRadius: BorderRadius.circular(12),
        boxShadow: [BoxShadow(color: color.withOpacity(0.3), blurRadius: 4)],
      ),
      child: Text(
        _getCategoryName(category, i18n),
        style: const TextStyle(
          color: Colors.white,
          fontSize: 12,
          fontWeight: FontWeight.bold,
        ),
      ),
    );
  }

  Widget _buildLegend(List<Color> colors, I18nService i18n) {
    int colorIndex = 0;
    return Wrap(
      spacing: 16,
      runSpacing: 8,
      children: _expensesByCategory.entries.map((entry) {
        final color = colors[colorIndex++ % colors.length];
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            Container(width: 14, height: 14, decoration: BoxDecoration(color: color, borderRadius: BorderRadius.circular(4))),
            const SizedBox(width: 6),
            Text(_getCategoryName(entry.key, i18n), style: const TextStyle(color: Colors.white)),
            const SizedBox(width: 6),
            Text(
              '${NumberFormat.currency(locale: i18n.locale.languageCode, symbol: _currentCurrency, decimalDigits: 2).format(entry.value)}',
              style: const TextStyle(color: Colors.white70, fontWeight: FontWeight.bold),
            ),
          ],
        );
      }).toList(),
    );
  }

  // Orçamentos do mês
  Widget _buildBudgetsChart(I18nService i18n) {
    if (_budgets.isEmpty) return Container();
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      child: Card(
        color: const Color(0xFF23204A),
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
        elevation: 4,
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(i18n.t('budgets'), style: const TextStyle(color: Colors.white, fontWeight: FontWeight.bold, fontSize: 18)),
              const SizedBox(height: 8),
              ..._budgets.asMap().entries.map((entry) {
                final idx = entry.key;
                final budget = entry.value;
                final spent = _budgetSpent[idx] ?? 0.0;
                final percent = budget.amount == 0 ? 0.0 : (spent / budget.amount).clamp(0.0, 1.0);
                return Padding(
                  padding: const EdgeInsets.symmetric(vertical: 6.0),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(
                        '${_getCategoryName(budget.category, i18n)}: $_currentCurrency ${spent.toStringAsFixed(2)} / ${budget.amount.toStringAsFixed(2)}',
                        style: const TextStyle(color: Colors.white70),
                      ),
                      LinearProgressIndicator(
                        value: percent,
                        backgroundColor: Colors.white12,
                        color: percent < 0.8 ? Colors.greenAccent : Colors.redAccent,
                        minHeight: 8,
                      ),
                    ],
                  ),
                );
              }),
            ],
          ),
        ),
      ),
    );
  }

  // Lista de transações do mês
  Widget _buildTransactionsList(I18nService i18n) {
    if (_transactions.isEmpty) return Container();
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      child: Card(
        color: const Color(0xFF23204A),
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
        elevation: 4,
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(i18n.t('transactions'), style: const TextStyle(color: Colors.white, fontWeight: FontWeight.bold, fontSize: 18)),
              const SizedBox(height: 8),
              ..._transactions.take(10).map((t) => ListTile(
                    leading: Icon(_getCategoryIcon(t.category), color: Colors.white70),
                    title: Text(t.title, style: const TextStyle(color: Colors.white)),
                    subtitle: Text(DateFormat('dd/MM/yyyy').format(t.date), style: const TextStyle(color: Colors.white54)),
                    trailing: Text(
                      '${t.type == TransactionType.income ? '+' : '-'}$_currentCurrency ${t.amount.toStringAsFixed(2)}',
                      style: TextStyle(
                        color: t.type == TransactionType.income ? Colors.greenAccent : Colors.redAccent,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                  )),
            ],
          ),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final i18n = Provider.of<I18nService>(context);

    bool hasData = _transactions.isNotEmpty || _budgets.isNotEmpty;

    return Scaffold(
      appBar: AppBar(
        title: Text(i18n.t('statistics_title')),
        centerTitle: true,
        backgroundColor: const Color(0xFF1E1C3A),
        elevation: 0,
      ),
      backgroundColor: const Color(0xFF1E1C3A),
      body: !hasData
          ? Center(
              child: Padding(
                padding: const EdgeInsets.all(16.0),
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Image.asset('assets/images/no_budget.png', width: 100, height: 100),
                    const SizedBox(height: 10),
                    Text(i18n.t('no_data'), style: const TextStyle(fontSize: 18, color: Colors.grey, fontWeight: FontWeight.bold)),
                    const SizedBox(height: 5),
                    Text(i18n.t('no_data_subtitle'), style: const TextStyle(color: Colors.grey)),
                  ],
                ),
              ),
            )
          : SingleChildScrollView(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  const SizedBox(height: 16),
                  _buildPeriodSelector(i18n),
                  _buildSummaryCard(i18n),
                  _buildExtraStatsList(i18n),
                  _buildBeautifulPieChart(i18n),
                  _buildBalanceLineChart(i18n),
                  const SizedBox(height: 16),
                  if (_budgets.isNotEmpty) _buildBudgetsChart(i18n),
                  const SizedBox(height: 16),
                  _buildTransactionsList(i18n),
                  const SizedBox(height: 16),
                ],
              ),
            ),
    );
  }
}