import { PrismaClient } from '@prisma/client';
import { ExportFormat } from '../../constants/export.constants';
import {
  BookingExportData,
  UserExportData,
  PaymentExportData,
  TournamentResultExportData,
  ExcelWorkbookData,
  ExportFilters
} from '../../types/analytics.types';
import { formatDateForExport } from '../../utils/export';

const prisma = new PrismaClient();

/**
 * Exporta reservas a CSV/JSON
 */
export async function exportBookings(
  startDate: Date,
  endDate: Date,
  format: ExportFormat = ExportFormat.CSV
): Promise<{ data: string | Buffer; filename: string }> {
  const bookings = await prisma.booking.findMany({
    where: {
      date: {
        gte: startDate,
        lte: endDate
      }
    },
    include: {
      user: {
        select: {
          firstName: true,
          lastName: true,
          email: true
        }
      },
      court: {
        select: {
          name: true
        }
      }
    },
    orderBy: {
      date: 'asc'
    }
  });

  const exportData: BookingExportData[] = bookings.map(booking => ({
    id: booking.id,
    user: `${booking.user.firstName} ${booking.user.lastName}`,
    userEmail: booking.user.email,
    court: booking.court.name,
    date: formatDateForExport(booking.date),
    time: booking.startTime,
    price: booking.price,
    status: booking.status,
    createdAt: formatDateForExport(booking.createdAt)
  }));

  const filename = `reservas_${startDate.toISOString().split('T')[0]}_${endDate.toISOString().split('T')[0]}`;

  if (format === ExportFormat.JSON) {
    return {
      data: JSON.stringify(exportData, null, 2),
      filename: `${filename}.json`
    };
  }

  // CSV por defecto
  const headers = {
    id: 'ID',
    user: 'Usuario',
    userEmail: 'Email',
    court: 'Pista',
    date: 'Fecha',
    time: 'Hora',
    price: 'Precio',
    status: 'Estado',
    createdAt: 'Fecha Creación'
  };

  const csv = convertToCSV(exportData, headers);
  return { data: csv, filename: `${filename}.csv` };
}

/**
 * Exporta usuarios a CSV/JSON
 */
export async function exportUsers(
  format: ExportFormat = ExportFormat.CSV,
  filters: ExportFilters = {}
): Promise<{ data: string | Buffer; filename: string }> {
  const where: Record<string, unknown> = {};

  if (filters.level) {
    where.level = filters.level;
  }

  if (filters.city) {
    where.city = filters.city;
  }

  const users = await prisma.user.findMany({
    where,
    include: {
      _count: {
        select: {
          bookings: true
        }
      }
    },
    orderBy: {
      createdAt: 'desc'
    }
  });

  const exportData: UserExportData[] = users.map(user => ({
    id: user.id,
    name: `${user.firstName} ${user.lastName}`,
    email: user.email,
    level: user.level || 'Sin nivel',
    city: user.city || 'Sin ciudad',
    joinedAt: formatDateForExport(user.createdAt),
    bookingsCount: user._count.bookings
  }));

  const filename = `usuarios_${new Date().toISOString().split('T')[0]}`;

  if (format === ExportFormat.JSON) {
    return {
      data: JSON.stringify(exportData, null, 2),
      filename: `${filename}.json`
    };
  }

  const headers = {
    id: 'ID',
    name: 'Nombre',
    email: 'Email',
    level: 'Nivel',
    city: 'Ciudad',
    joinedAt: 'Fecha Registro',
    bookingsCount: 'Total Reservas'
  };

  const csv = convertToCSV(exportData, headers);
  return { data: csv, filename: `${filename}.csv` };
}

/**
 * Exporta pagos a CSV/JSON
 */
export async function exportPayments(
  startDate: Date,
  endDate: Date,
  format: ExportFormat = ExportFormat.CSV
): Promise<{ data: string | Buffer; filename: string }> {
  // Asumiendo que existe un modelo Payment o similar
  // Aquí usamos bookings como referencia de pagos
  const bookings = await prisma.booking.findMany({
    where: {
      createdAt: {
        gte: startDate,
        lte: endDate
      },
      status: {
        in: ['PAID', 'CONFIRMED', 'COMPLETED']
      }
    },
    include: {
      user: {
        select: {
          firstName: true,
          lastName: true,
          email: true
        }
      }
    },
    orderBy: {
      createdAt: 'asc'
    }
  });

  const exportData: PaymentExportData[] = bookings.map(booking => ({
    id: booking.id,
    user: `${booking.user.firstName} ${booking.user.lastName}`,
    userEmail: booking.user.email,
    type: 'Reserva',
    amount: booking.price,
    status: booking.status,
    date: formatDateForExport(booking.createdAt)
  }));

  const filename = `pagos_${startDate.toISOString().split('T')[0]}_${endDate.toISOString().split('T')[0]}`;

  if (format === ExportFormat.JSON) {
    return {
      data: JSON.stringify(exportData, null, 2),
      filename: `${filename}.json`
    };
  }

  const headers = {
    id: 'ID',
    user: 'Usuario',
    userEmail: 'Email',
    type: 'Tipo',
    amount: 'Monto',
    status: 'Estado',
    date: 'Fecha'
  };

  const csv = convertToCSV(exportData, headers);
  return { data: csv, filename: `${filename}.csv` };
}

/**
 * Exporta resultados de un torneo
 */
export async function exportTournamentResults(
  tournamentId: string,
  format: ExportFormat = ExportFormat.CSV
): Promise<{ data: string | Buffer; filename: string }> {
  const tournament = await prisma.tournament.findUnique({
    where: { id: tournamentId },
    include: {
      participants: {
        include: {
          user: {
            select: {
              firstName: true,
              lastName: true,
              email: true
            }
          }
        }
      },
      matches: {
        where: {
          confirmed: true
        }
      }
    }
  });

  if (!tournament) {
    throw new Error('Torneo no encontrado');
  }

  // Calcular estadísticas por participante
  const participantStats = new Map<string, {
    matchesPlayed: number;
    wins: number;
    losses: number;
    points: number;
  }>();

  for (const match of tournament.matches) {
    // Actualizar estadísticas para cada jugador del partido
    const matchParticipants = await prisma.tournamentParticipant.findMany({
      where: {
        tournamentId,
        userId: {
          in: [match.player1Id, match.player2Id].filter(Boolean) as string[]
        }
      }
    });

    for (const participant of matchParticipants) {
      const stats = participantStats.get(participant.userId) || {
        matchesPlayed: 0,
        wins: 0,
        losses: 0,
        points: 0
      };

      stats.matchesPlayed++;
      
      if (match.winnerId === participant.userId) {
        stats.wins++;
        stats.points += 3; // 3 puntos por victoria
      } else if (match.winnerId) {
        stats.losses++;
        stats.points += 1; // 1 punto por participar
      }

      participantStats.set(participant.userId, stats);
    }
  }

  const exportData: TournamentResultExportData[] = tournament.participants
    .map((participant, index) => {
      const stats = participantStats.get(participant.userId) || {
        matchesPlayed: 0,
        wins: 0,
        losses: 0,
        points: 0
      };

      return {
        position: index + 1,
        player: `${participant.user.firstName} ${participant.user.lastName}`,
        email: participant.user.email,
        matchesPlayed: stats.matchesPlayed,
        wins: stats.wins,
        losses: stats.losses,
        points: stats.points
      };
    })
    .sort((a, b) => b.points - a.points)
    .map((item, index) => ({ ...item, position: index + 1 }));

  const filename = `torneo_${tournament.name.replace(/\s+/g, '_').toLowerCase()}_${tournamentId}`;

  if (format === ExportFormat.JSON) {
    return {
      data: JSON.stringify(exportData, null, 2),
      filename: `${filename}.json`
    };
  }

  const headers = {
    position: 'Posición',
    player: 'Jugador',
    email: 'Email',
    matchesPlayed: 'PJ',
    wins: 'PG',
    losses: 'PP',
    points: 'Puntos'
  };

  const csv = convertToCSV(exportData, headers);
  return { data: csv, filename: `${filename}.csv` };
}

/**
 * Genera un reporte completo en Excel con múltiples hojas
 */
export async function generateExcelReport(
  startDate: Date,
  endDate: Date
): Promise<{ data: Buffer; filename: string }> {
  // Importar xlsx dinámicamente para evitar problemas si no está instalado
  const xlsx = await import('xlsx');

  // 1. Resumen General
  const totalBookings = await prisma.booking.count({
    where: {
      date: {
        gte: startDate,
        lte: endDate
      }
    }
  });

  const totalRevenue = await prisma.booking.aggregate({
    where: {
      date: {
        gte: startDate,
        lte: endDate
      },
      status: {
        in: ['PAID', 'CONFIRMED', 'COMPLETED']
      }
    },
    _sum: {
      price: true
    }
  });

  const newUsers = await prisma.user.count({
    where: {
      createdAt: {
        gte: startDate,
        lte: endDate
      }
    }
  });

  const activeUsers = await prisma.user.count({
    where: {
      bookings: {
        some: {
          date: {
            gte: startDate,
            lte: endDate
          }
        }
      }
    }
  });

  const summaryData = [{
    metrica: 'Total Reservas',
    valor: totalBookings
  }, {
    metrica: 'Ingresos Totales',
    valor: totalRevenue._sum.price || 0
  }, {
    metrica: 'Nuevos Usuarios',
    valor: newUsers
  }, {
    metrica: 'Usuarios Activos',
    valor: activeUsers
  }];

  // 2. Datos de Ingresos por Día
  const bookingsByDay = await prisma.booking.groupBy({
    by: ['date'],
    where: {
      date: {
        gte: startDate,
        lte: endDate
      },
      status: {
        in: ['PAID', 'CONFIRMED', 'COMPLETED']
      }
    },
    _sum: {
      price: true
    },
    _count: {
      id: true
    }
  });

  const revenueData = bookingsByDay.map(day => ({
    fecha: day.date.toISOString().split('T')[0],
    reservas: day._count.id,
    ingresos: day._sum.price || 0
  }));

  // 3. Datos de Ocupación por Pista
  const courts = await prisma.court.findMany({
    include: {
      bookings: {
        where: {
          date: {
            gte: startDate,
            lte: endDate
          }
        }
      }
    }
  });

  const occupancyData = courts.map(court => ({
    pista: court.name,
    tipo: court.surface || 'No especificado',
    totalReservas: court.bookings.length,
    tasaOcupacion: calculateOccupancyRate(court.bookings.length, startDate, endDate)
  }));

  // 4. Datos de Usuarios
  const topUsers = await prisma.user.findMany({
    take: 20,
    include: {
      bookings: {
        where: {
          date: {
            gte: startDate,
            lte: endDate
          }
        }
      },
      _count: {
        select: {
          bookings: true
        }
      }
    },
    orderBy: {
      bookings: {
        _count: 'desc'
      }
    }
  });

  const usersData = topUsers.map(user => ({
    nombre: `${user.firstName} ${user.lastName}`,
    email: user.email,
    nivel: user.level || 'Sin nivel',
    reservasPeriodo: user.bookings.length,
    reservasTotales: user._count.bookings
  }));

  // Crear workbook
  const workbook = xlsx.utils.book_new();

  // Hoja 1: Resumen
  const summarySheet = xlsx.utils.json_to_sheet(summaryData);
  xlsx.utils.book_append_sheet(workbook, summarySheet, 'Resumen');

  // Hoja 2: Ingresos
  const revenueSheet = xlsx.utils.json_to_sheet(revenueData);
  xlsx.utils.book_append_sheet(workbook, revenueSheet, 'Ingresos');

  // Hoja 3: Ocupación
  const occupancySheet = xlsx.utils.json_to_sheet(occupancyData);
  xlsx.utils.book_append_sheet(workbook, occupancySheet, 'Ocupación');

  // Hoja 4: Usuarios
  const usersSheet = xlsx.utils.json_to_sheet(usersData);
  xlsx.utils.book_append_sheet(workbook, usersSheet, 'Usuarios');

  const buffer = xlsx.write(workbook, { type: 'buffer', bookType: 'xlsx' });
  const filename = `reporte_completo_${startDate.toISOString().split('T')[0]}_${endDate.toISOString().split('T')[0]}.xlsx`;

  return { data: buffer, filename };
}

/**
 * Convierte datos a formato CSV
 */
function convertToCSV(data: Record<string, unknown>[], headers: Record<string, string>): string {
  const CSV_SEPARATOR = ';';
  
  if (data.length === 0) {
    return Object.values(headers).join(CSV_SEPARATOR);
  }

  const headerRow = Object.values(headers).join(CSV_SEPARATOR);
  const keys = Object.keys(headers);

  const rows = data.map(item => {
    return keys.map(key => {
      const value = item[key];
      if (value === null || value === undefined) {
        return '';
      }
      if (typeof value === 'string' && (value.includes(CSV_SEPARATOR) || value.includes('"') || value.includes('\n'))) {
        return `"${value.replace(/"/g, '""')}"`;
      }
      return String(value);
    }).join(CSV_SEPARATOR);
  });

  return [headerRow, ...rows].join('\n');
}

/**
 * Calcula la tasa de ocupación estimada
 */
function calculateOccupancyRate(
  bookingCount: number,
  startDate: Date,
  endDate: Date
): string {
  const daysDiff = Math.ceil((endDate.getTime() - startDate.getTime()) / (1000 * 60 * 60 * 24));
  const maxPossibleBookings = daysDiff * 10; // Asumiendo 10 franjas horarias por día
  const rate = maxPossibleBookings > 0 ? (bookingCount / maxPossibleBookings) * 100 : 0;
  return `${rate.toFixed(1)}%`;
}