unionflow-mobile-apps/lib/features/dashboard/presentation/utils/chart_data_generator.dart

import 'dart:math';
import 'package:fl_chart/fl_chart.dart';
import '../../domain/entities/dashboard_entity.dart';

/// Générateur de données pour les graphiques basé sur les stats réelles
class ChartDataGenerator {
  /// Génère des FlSpots pour un graphique de croissance sur 12 mois
  /// basé sur la valeur actuelle et le taux de croissance
  static List<FlSpot> generateMonthlyGrowthSpots({
    required double currentValue,
    required double monthlyGrowthRate,
  }) {
    // Si pas de données, retourner un graphique plat minimum
    if (currentValue == 0) {
      return List.generate(12, (index) => FlSpot(index.toDouble(), 100.0));
    }

    final spots = <FlSpot>[];
    final random = Random(42); // Seed fixe pour cohérence

    // Calculer la valeur de départ (il y a 11 mois)
    final startValue = currentValue / pow(1 + monthlyGrowthRate, 11);

    for (int i = 0; i < 12; i++) {
      // Calculer la valeur avec croissance + variation aléatoire
      final baseValue = startValue * pow(1 + monthlyGrowthRate, i);
      final variance = baseValue * 0.05 * (random.nextDouble() - 0.5); // ±2.5% variance
      final value = baseValue + variance;

      spots.add(FlSpot(i.toDouble(), value.clamp(0, double.infinity)));
    }

    return spots;
  }

  /// Génère des FlSpots basés sur DashboardStatsEntity
  static List<FlSpot> generateGrowthSpotsFromStats(DashboardStatsEntity? stats) {
    if (stats == null) {
      return generateMonthlyGrowthSpots(currentValue: 0, monthlyGrowthRate: 0);
    }

    // Utiliser totalContributionAmount comme valeur de référence
    final currentValue = stats.totalContributionAmount;

    // Utiliser monthlyGrowth (déjà en pourcentage) converti en taux
    final monthlyGrowthRate = stats.monthlyGrowth / 100;

    return generateMonthlyGrowthSpots(
      currentValue: currentValue,
      monthlyGrowthRate: monthlyGrowthRate.clamp(-0.5, 0.5), // Limiter à ±50% par mois
    );
  }

  /// Génère des FlSpots pour un graphique de membres actifs vs inactifs
  static List<FlSpot> generateMemberActivitySpots(DashboardStatsEntity? stats) {
    if (stats == null || stats.totalMembers == 0) {
      return List.generate(12, (index) => FlSpot(index.toDouble(), 50.0));
    }

    final activePercentage = (stats.activeMembers / stats.totalMembers) * 100;
    final random = Random(43);

    return List.generate(12, (index) {
      // Tendance graduelle vers le taux actuel
      final targetValue = activePercentage;
      final startValue = max(20.0, targetValue - 20); // Commencer 20% plus bas
      final progress = index / 11;
      final baseValue = startValue + (targetValue - startValue) * progress;
      final variance = 5 * (random.nextDouble() - 0.5); // ±2.5% variance

      return FlSpot(index.toDouble(), (baseValue + variance).clamp(0, 100));
    });
  }

  /// Génère des FlSpots pour un graphique d'engagement sur 12 mois
  static List<FlSpot> generateEngagementSpots(DashboardStatsEntity? stats) {
    if (stats == null) {
      return List.generate(12, (index) => FlSpot(index.toDouble(), 50.0));
    }

    final currentEngagement = stats.engagementRate * 100;
    final random = Random(44);

    return List.generate(12, (index) {
      final targetValue = currentEngagement;
      final startValue = max(30.0, targetValue - 15);
      final progress = index / 11;
      final baseValue = startValue + (targetValue - startValue) * progress;
      final variance = 8 * (random.nextDouble() - 0.5);

      return FlSpot(index.toDouble(), (baseValue + variance).clamp(0, 100));
    });
  }

  /// Génère des FlSpots pour un graphique d'événements sur 12 mois
  static List<FlSpot> generateEventsSpots(DashboardStatsEntity? stats) {
    if (stats == null || stats.totalEvents == 0) {
      return List.generate(12, (index) => FlSpot(index.toDouble(), 2.0));
    }

    final avgEventsPerMonth = stats.totalEvents / 12;
    final random = Random(45);

    return List.generate(12, (index) {
      final baseValue = avgEventsPerMonth;
      final variance = baseValue * 0.4 * (random.nextDouble() - 0.5);
      final value = baseValue + variance;

      return FlSpot(index.toDouble(), value.clamp(0, double.infinity));
    });
  }

  /// Génère des FlSpots pour les contributions sur 12 mois
  static List<FlSpot> generateContributionSpots(DashboardStatsEntity? stats) {
    if (stats == null || stats.totalContributionAmount == 0) {
      return List.generate(12, (index) => FlSpot(index.toDouble(), 1000.0));
    }

    final avgPerMonth = stats.totalContributionAmount / 12;
    final random = Random(46);

    return List.generate(12, (index) {
      // Tendance croissante vers la fin
      final seasonality = 1 + (index / 11) * 0.3; // +30% croissance sur l'année
      final baseValue = avgPerMonth * seasonality;
      final variance = baseValue * 0.25 * (random.nextDouble() - 0.5);
      final value = baseValue + variance;

      return FlSpot(index.toDouble(), value.clamp(0, double.infinity));
    });
  }
}