import 'package:flutter/material.dart';
import 'package:fl_chart/fl_chart.dart';
import 'package:intl/intl.dart';
import '../models/statistiche.dart';
import '../services/api_service.dart';
import '../utils/constants.dart';

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

  @override
  State<DashboardScreen> createState() => _DashboardScreenState();
}

class _DashboardScreenState extends State<DashboardScreen> {
  final _apiService = ApiService();
  Statistiche? _statistiche;
  AllarmiPerGiornoResponse? _allarmiPerGiorno;
  bool _isLoading = true;
  String? _errorMessage;

  @override
  void initState() {
    super.initState();
    _loadData();
  }

  Future<void> _loadData() async {
    setState(() => _isLoading = true);

    try {
      final stats = await _apiService.getStatistiche();
      final allarmiGiorno = await _apiService.getAllarmiPerGiorno(giorni: 30);

      setState(() {
        _statistiche = stats;
        _allarmiPerGiorno = allarmiGiorno;
        _isLoading = false;
        _errorMessage = null;
      });
    } catch (e) {
      setState(() {
        _errorMessage = 'Errore caricamento dati: $e';
        _isLoading = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text('Dashboard'),
            Text('Panoramica generale', style: TextStyle(fontSize: 12)),
          ],
        ),
        actions: [
          IconButton(
            icon: const Icon(Icons.refresh),
            onPressed: _loadData,
          ),
        ],
      ),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : _errorMessage != null
              ? Center(
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: [
                      const Icon(
                        Icons.error_outline,
                        size: 64,
                        color: AppColors.critical,
                      ),
                      const SizedBox(height: 16),
                      Text(_errorMessage!),
                      const SizedBox(height: 16),
                      ElevatedButton.icon(
                        onPressed: _loadData,
                        icon: const Icon(Icons.refresh),
                        label: const Text('Riprova'),
                      ),
                    ],
                  ),
                )
              : RefreshIndicator(
                  onRefresh: _loadData,
                  child: SingleChildScrollView(
                    padding: const EdgeInsets.all(AppSizes.paddingL),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        // KPI Cards
                        _buildKPISection(),
                        const SizedBox(height: 24),

                        // Grafico Severità
                        _buildSeveritaChart(),
                        const SizedBox(height: 24),

                        // Grafico Stati
                        _buildStatiChart(),
                        const SizedBox(height: 24),

                        // Grafico Temporale
                        _buildTimelineChart(),
                        const SizedBox(height: 24),

                        // Grafico Siti per Tipo
                        _buildSitiPerTipoChart(),
                      ],
                    ),
                  ),
                ),
    );
  }

  Widget _buildKPISection() {
    if (_statistiche == null) return const SizedBox.shrink();

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        const Text('Indicatori Chiave', style: AppTextStyles.h2),
        const SizedBox(height: 12),
        Row(
          children: [
            Expanded(
              child: _buildKPICard(
                'Allarmi Totali',
                _statistiche!.totaleAllarmi.toString(),
                Icons.notifications_active,
                AppColors.primary,
              ),
            ),
            const SizedBox(width: AppSizes.paddingM),
            Expanded(
              child: _buildKPICard(
                'Siti Monitorati',
                _statistiche!.totaleSiti.toString(),
                Icons.location_on,
                AppColors.secondary,
              ),
            ),
          ],
        ),
        const SizedBox(height: AppSizes.paddingM),
        Row(
          children: [
            Expanded(
              child: _buildKPICard(
                'Aperti',
                _statistiche!.allarmiAperti.toString(),
                Icons.warning,
                AppColors.warning,
                subtitle:
                    '${_statistiche!.percentualeAperti.toStringAsFixed(1)}%',
              ),
            ),
            const SizedBox(width: AppSizes.paddingM),
            Expanded(
              child: _buildKPICard(
                'Critici',
                _statistiche!.allarmiCritical.toString(),
                Icons.error,
                AppColors.critical,
                subtitle:
                    '${_statistiche!.percentualeCritici.toStringAsFixed(1)}%',
              ),
            ),
          ],
        ),
      ],
    );
  }

  Widget _buildKPICard(
    String label,
    String value,
    IconData icon,
    Color color, {
    String? subtitle,
  }) {
    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        gradient: LinearGradient(
          begin: Alignment.topLeft,
          end: Alignment.bottomRight,
          colors: [color, color.withOpacity(0.7)],
        ),
        borderRadius: BorderRadius.circular(16),
        boxShadow: [
          BoxShadow(
            color: color.withOpacity(0.3),
            blurRadius: 8,
            offset: const Offset(0, 4),
          ),
        ],
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Icon(icon, color: Colors.white, size: 28),
          const SizedBox(height: 12),
          Text(
            value,
            style: const TextStyle(
              color: Colors.white,
              fontSize: 32,
              fontWeight: FontWeight.bold,
            ),
          ),
          const SizedBox(height: 4),
          Text(
            label,
            style: TextStyle(
              color: Colors.white.withOpacity(0.9),
              fontSize: 14,
            ),
          ),
          if (subtitle != null) ...[
            const SizedBox(height: 4),
            Text(
              subtitle,
              style: const TextStyle(
                color: Colors.white,
                fontSize: 12,
                fontWeight: FontWeight.bold,
              ),
            ),
          ],
        ],
      ),
    );
  }

  Widget _buildSeveritaChart() {
    if (_statistiche == null) return const SizedBox.shrink();

    final sections = [
      if (_statistiche!.allarmiCritical > 0)
        PieChartSectionData(
          color: AppColors.critical,
          value: _statistiche!.allarmiCritical.toDouble(),
          title: '${_statistiche!.allarmiCritical}',
          radius: 50,
          titleStyle: const TextStyle(
            fontSize: 14,
            fontWeight: FontWeight.bold,
            color: Colors.white,
          ),
        ),
      if (_statistiche!.allarmiWarning > 0)
        PieChartSectionData(
          color: AppColors.warning,
          value: _statistiche!.allarmiWarning.toDouble(),
          title: '${_statistiche!.allarmiWarning}',
          radius: 50,
          titleStyle: const TextStyle(
            fontSize: 14,
            fontWeight: FontWeight.bold,
            color: Colors.white,
          ),
        ),
      if (_statistiche!.allarmiInfo > 0)
        PieChartSectionData(
          color: AppColors.info,
          value: _statistiche!.allarmiInfo.toDouble(),
          title: '${_statistiche!.allarmiInfo}',
          radius: 50,
          titleStyle: const TextStyle(
            fontSize: 14,
            fontWeight: FontWeight.bold,
            color: Colors.white,
          ),
        ),
    ];

    if (sections.isEmpty) {
      return const SizedBox.shrink();
    }

    return _buildChartCard(
      'Allarmi per Severità',
      Column(
        children: [
          SizedBox(
            height: 200,
            child: PieChart(
              PieChartData(
                sections: sections,
                sectionsSpace: 2,
                centerSpaceRadius: 40,
              ),
            ),
          ),
          const SizedBox(height: 16),
          _buildLegend([
            _LegendItem('Critici', AppColors.critical, _statistiche!.allarmiCritical),
            _LegendItem('Avvisi', AppColors.warning, _statistiche!.allarmiWarning),
            _LegendItem('Info', AppColors.info, _statistiche!.allarmiInfo),
          ]),
        ],
      ),
    );
  }

  Widget _buildStatiChart() {
    if (_statistiche == null) return const SizedBox.shrink();

    return _buildChartCard(
      'Allarmi per Stato',
      Column(
        children: [
          SizedBox(
            height: 200,
            child: BarChart(
              BarChartData(
                alignment: BarChartAlignment.spaceAround,
                maxY: _statistiche!.totaleStato.toDouble() * 1.2,
                barTouchData: BarTouchData(enabled: false),
                titlesData: FlTitlesData(
                  show: true,
                  bottomTitles: AxisTitles(
                    sideTitles: SideTitles(
                      showTitles: true,
                      getTitlesWidget: (value, meta) {
                        switch (value.toInt()) {
                          case 0:
                            return const Text('Nuovi', style: TextStyle(fontSize: 12));
                          case 1:
                            return const Text('In Gest.', style: TextStyle(fontSize: 12));
                          case 2:
                            return const Text('Risolti', style: TextStyle(fontSize: 12));
                          default:
                            return const Text('');
                        }
                      },
                    ),
                  ),
                  leftTitles: const AxisTitles(
                    sideTitles: SideTitles(showTitles: false),
                  ),
                  topTitles: const AxisTitles(
                    sideTitles: SideTitles(showTitles: false),
                  ),
                  rightTitles: const AxisTitles(
                    sideTitles: SideTitles(showTitles: false),
                  ),
                ),
                borderData: FlBorderData(show: false),
                barGroups: [
                  BarChartGroupData(
                    x: 0,
                    barRods: [
                      BarChartRodData(
                        toY: _statistiche!.allarmiNuovo.toDouble(),
                        color: AppColors.critical,
                        width: 40,
                        borderRadius: const BorderRadius.vertical(top: Radius.circular(4)),
                      ),
                    ],
                  ),
                  BarChartGroupData(
                    x: 1,
                    barRods: [
                      BarChartRodData(
                        toY: _statistiche!.allarmiInGestione.toDouble(),
                        color: AppColors.warning,
                        width: 40,
                        borderRadius: const BorderRadius.vertical(top: Radius.circular(4)),
                      ),
                    ],
                  ),
                  BarChartGroupData(
                    x: 2,
                    barRods: [
                      BarChartRodData(
                        toY: _statistiche!.allarmiRisolto.toDouble(),
                        color: AppColors.success,
                        width: 40,
                        borderRadius: const BorderRadius.vertical(top: Radius.circular(4)),
                      ),
                    ],
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildTimelineChart() {
    if (_allarmiPerGiorno == null || _allarmiPerGiorno!.dati.isEmpty) {
      return const SizedBox.shrink();
    }

    final spots = _allarmiPerGiorno!.dati.asMap().entries.map((entry) {
      return FlSpot(entry.key.toDouble(), entry.value.count.toDouble());
    }).toList();

    final maxY = _allarmiPerGiorno!.dati
        .map((d) => d.count)
        .reduce((a, b) => a > b ? a : b)
        .toDouble();

    return _buildChartCard(
      'Andamento Temporale (30 giorni)',
      SizedBox(
        height: 200,
        child: LineChart(
          LineChartData(
            gridData: FlGridData(
              show: true,
              drawVerticalLine: false,
              horizontalInterval: 1,
              getDrawingHorizontalLine: (value) {
                return FlLine(
                  color: Colors.grey[300],
                  strokeWidth: 1,
                );
              },
            ),
            titlesData: FlTitlesData(
              show: true,
              bottomTitles: AxisTitles(
                sideTitles: SideTitles(
                  showTitles: true,
                  reservedSize: 30,
                  interval: 5,
                  getTitlesWidget: (value, meta) {
                    if (value.toInt() >= _allarmiPerGiorno!.dati.length) {
                      return const Text('');
                    }
                    final data = _allarmiPerGiorno!.dati[value.toInt()].data;
                    return Text(
                      DateFormat('d/M').format(data),
                      style: const TextStyle(fontSize: 10),
                    );
                  },
                ),
              ),
              leftTitles: const AxisTitles(
                sideTitles: SideTitles(showTitles: false),
              ),
              topTitles: const AxisTitles(
                sideTitles: SideTitles(showTitles: false),
              ),
              rightTitles: const AxisTitles(
                sideTitles: SideTitles(showTitles: false),
              ),
            ),
            borderData: FlBorderData(show: false),
            minX: 0,
            maxX: spots.length.toDouble() - 1,
            minY: 0,
            maxY: maxY * 1.2,
            lineBarsData: [
              LineChartBarData(
                spots: spots,
                isCurved: true,
                color: AppColors.primary,
                barWidth: 3,
                isStrokeCapRound: true,
                dotData: const FlDotData(show: false),
                belowBarData: BarAreaData(
                  show: true,
                  color: AppColors.primary.withOpacity(0.1),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildSitiPerTipoChart() {
    if (_statistiche == null) return const SizedBox.shrink();

    final data = [
      _ChartData('Ponti', _statistiche!.sitiPonte, Colors.blue),
      _ChartData('Gallerie', _statistiche!.sitiGalleria, Colors.brown),
      _ChartData('Dighe', _statistiche!.sitiDiga, Colors.cyan),
      _ChartData('Frane', _statistiche!.sitiFrana, Colors.orange),
      _ChartData('Versanti', _statistiche!.sitiVersante, Colors.green),
      _ChartData('Edifici', _statistiche!.sitiEdificio, Colors.purple),
    ].where((d) => d.value > 0).toList();

    if (data.isEmpty) return const SizedBox.shrink();

    return _buildChartCard(
      'Siti per Tipologia',
      SizedBox(
        height: 200,
        child: BarChart(
          BarChartData(
            alignment: BarChartAlignment.spaceAround,
            maxY: data.map((d) => d.value).reduce((a, b) => a > b ? a : b).toDouble() * 1.2,
            barTouchData: BarTouchData(enabled: false),
            titlesData: FlTitlesData(
              show: true,
              bottomTitles: AxisTitles(
                sideTitles: SideTitles(
                  showTitles: true,
                  getTitlesWidget: (value, meta) {
                    if (value.toInt() >= data.length) return const Text('');
                    return Text(
                      data[value.toInt()].label.substring(0, 3),
                      style: const TextStyle(fontSize: 12),
                    );
                  },
                ),
              ),
              leftTitles: const AxisTitles(
                sideTitles: SideTitles(showTitles: false),
              ),
              topTitles: const AxisTitles(
                sideTitles: SideTitles(showTitles: false),
              ),
              rightTitles: const AxisTitles(
                sideTitles: SideTitles(showTitles: false),
              ),
            ),
            borderData: FlBorderData(show: false),
            barGroups: data.asMap().entries.map((entry) {
              return BarChartGroupData(
                x: entry.key,
                barRods: [
                  BarChartRodData(
                    toY: entry.value.value.toDouble(),
                    color: entry.value.color,
                    width: 30,
                    borderRadius: const BorderRadius.vertical(top: Radius.circular(4)),
                  ),
                ],
              );
            }).toList(),
          ),
        ),
      ),
    );
  }

  Widget _buildChartCard(String title, Widget child) {
    return Container(
      padding: const EdgeInsets.all(AppSizes.paddingL),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(16),
        boxShadow: [
          BoxShadow(
            color: Colors.black.withOpacity(0.05),
            blurRadius: 10,
            offset: const Offset(0, 4),
          ),
        ],
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(title, style: AppTextStyles.h3),
          const SizedBox(height: 16),
          child,
        ],
      ),
    );
  }

  Widget _buildLegend(List<_LegendItem> items) {
    return Wrap(
      spacing: 16,
      runSpacing: 8,
      children: items.map((item) {
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            Container(
              width: 16,
              height: 16,
              decoration: BoxDecoration(
                color: item.color,
                shape: BoxShape.circle,
              ),
            ),
            const SizedBox(width: 8),
            Text(
              '${item.label}: ${item.value}',
              style: AppTextStyles.bodySmall,
            ),
          ],
        );
      }).toList(),
    );
  }
}

class _LegendItem {
  final String label;
  final Color color;
  final int value;

  _LegendItem(this.label, this.color, this.value);
}

class _ChartData {
  final String label;
  final int value;
  final Color color;

  _ChartData(this.label, this.value, this.color);
}