import { NextRequest, NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/lib/auth';
import { prisma } from '@/lib/prisma';

export async function GET(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions);
    
    if (!session || session.user.role !== 'ADMIN') {
      return NextResponse.json(
        { message: 'No tienes permisos para acceder a los reportes' },
        { status: 403 }
      );
    }

    const { searchParams } = new URL(request.url);
    const reportType = searchParams.get('type');
    const periodId = searchParams.get('periodId');
    const startDate = searchParams.get('startDate');
    const endDate = searchParams.get('endDate');

    switch (reportType) {
      case 'overview':
        return await getOverviewReport();
      case 'students':
        return await getStudentsReport(periodId);
      case 'teachers':
        return await getTeachersReport(periodId);
      case 'attendance':
        return await getAttendanceReport(periodId, startDate, endDate);
      case 'enrollments':
        return await getEnrollmentsReport(periodId);
      case 'classes':
        return await getClassesReport(periodId);
      default:
        return await getOverviewReport();
    }
  } catch (error) {
    console.error('Error generating report:', error);
    return NextResponse.json(
      { message: 'Error interno del servidor' },
      { status: 500 }
    );
  }
}

// Reporte general del sistema
async function getOverviewReport() {
  try {
    const [totalUsers, totalStudents, totalTeachers, totalClasses, totalSections, activePeriods] = await Promise.all([
      prisma.user.count(),
      prisma.student.count({ where: { isActive: true } }),
      prisma.teacher.count({ where: { isActive: true } }),
      prisma.class.count({ where: { isActive: true } }),
      prisma.section.count({ where: { isActive: true } }),
      prisma.period.count({ where: { isActive: true } })
    ]);

    const usersByRole = await prisma.user.groupBy({
      by: ['role'],
      _count: {
        id: true
      }
    });

    const recentEnrollments = await prisma.studentEnrollment.count({
      where: {
        createdAt: {
          gte: new Date(Date.now() - 30 * 24 * 60 * 60 * 1000) // Últimos 30 días
        }
      }
    });

    const recentAttendance = await prisma.attendance.count({
      where: {
        createdAt: {
          gte: new Date(Date.now() - 7 * 24 * 60 * 60 * 1000) // Últimos 7 días
        }
      }
    });

    return NextResponse.json({
      overview: {
        totalUsers,
        totalStudents,
        totalTeachers,
        totalClasses,
        totalSections,
        activePeriods,
        recentEnrollments,
        recentAttendance
      },
      usersByRole: usersByRole.map(item => ({
        role: item.role,
        count: item._count.id
      }))
    });
  } catch (error) {
    console.error('Error in overview report:', error);
    throw error;
  }
}

// Reporte de estudiantes
async function getStudentsReport(periodId: string | null) {
  try {
    const whereClause = periodId ? {
      enrollments: {
        some: {
          section: {
            class: {
              periodId: periodId
            }
          }
        }
      }
    } : {};

    const students = await prisma.student.findMany({
      where: {
        isActive: true,
        ...whereClause
      },
      include: {
        enrollments: {
          where: {
            isActive: true,
            ...(periodId ? {
              section: {
                class: {
                  periodId: periodId
                }
              }
            } : {})
          },
          include: {
            section: {
              include: {
                class: {
                  include: {
                    period: true
                  }
                }
              }
            }
          }
        },
        attendances: {
          where: {
            ...(periodId ? {
              section: {
                class: {
                  periodId: periodId
                }
              }
            } : {})
          }
        }
      },
      orderBy: {
        lastName: 'asc'
      }
    });

    const studentsWithStats = students.map(student => {
      const totalAttendances = student.attendances.length;
      const presentAttendances = student.attendances.filter(a => a.status === 'PRESENT').length;
      const attendanceRate = totalAttendances > 0 ? (presentAttendances / totalAttendances) * 100 : 0;

      return {
        id: student.id,
        firstName: student.firstName,
        lastName: student.lastName,
        cedula: student.cedula,
        email: student.email,
        admissionNumber: student.admissionNumber,
        enrollmentsCount: student.enrollments.length,
        attendanceRate: Math.round(attendanceRate * 100) / 100,
        totalAttendances,
        presentAttendances,
        enrollments: student.enrollments.map(enrollment => ({
          sectionName: enrollment.section.name,
          className: enrollment.section.class.name,
          classCode: enrollment.section.class.code,
          periodName: enrollment.section.class.period.name
        }))
      };
    });

    return NextResponse.json({
      students: studentsWithStats,
      summary: {
        totalStudents: students.length,
        averageEnrollments: students.length > 0 ? students.reduce((sum, s) => sum + s.enrollments.length, 0) / students.length : 0,
        averageAttendanceRate: studentsWithStats.length > 0 ? studentsWithStats.reduce((sum, s) => sum + s.attendanceRate, 0) / studentsWithStats.length : 0
      }
    });
  } catch (error) {
    console.error('Error in students report:', error);
    throw error;
  }
}

// Reporte de profesores
async function getTeachersReport(periodId: string | null) {
  try {
    const whereClause = periodId ? {
      assignments: {
        some: {
          section: {
            class: {
              periodId: periodId
            }
          }
        }
      }
    } : {};

    const teachers = await prisma.teacher.findMany({
      where: {
        isActive: true,
        ...whereClause
      },
      include: {
        assignments: {
          where: {
            isActive: true,
            ...(periodId ? {
              section: {
                class: {
                  periodId: periodId
                }
              }
            } : {})
          },
          include: {
            section: {
              include: {
                class: {
                  include: {
                    period: true
                  }
                },
                studentEnrollments: {
                  where: {
                    isActive: true
                  }
                }
              }
            }
          }
        }
      },
      orderBy: {
        lastName: 'asc'
      }
    });

    const teachersWithStats = teachers.map(teacher => {
      const totalStudents = teacher.assignments.reduce((sum, assignment) => 
        sum + assignment.section.studentEnrollments.length, 0
      );

      return {
        id: teacher.id,
        firstName: teacher.firstName,
        lastName: teacher.lastName,
        cedula: teacher.cedula,
        email: teacher.email,
        phone: teacher.phone,
        assignmentsCount: teacher.assignments.length,
        totalStudents,
        assignments: teacher.assignments.map(assignment => ({
          sectionName: assignment.section.name,
          className: assignment.section.class.name,
          classCode: assignment.section.class.code,
          periodName: assignment.section.class.period.name,
          studentsCount: assignment.section.studentEnrollments.length
        }))
      };
    });

    return NextResponse.json({
      teachers: teachersWithStats,
      summary: {
        totalTeachers: teachers.length,
        averageAssignments: teachers.length > 0 ? teachers.reduce((sum, t) => sum + t.assignments.length, 0) / teachers.length : 0,
        totalStudentsManaged: teachersWithStats.reduce((sum, t) => sum + t.totalStudents, 0)
      }
    });
  } catch (error) {
    console.error('Error in teachers report:', error);
    throw error;
  }
}

/* eslint-disable  @typescript-eslint/no-explicit-any */

// Reporte de asistencia
async function getAttendanceReport(periodId: string | null, startDate: string | null, endDate: string | null) {
  try {
    const dateFilter: any = {};
    if (startDate) dateFilter.gte = new Date(startDate);
    if (endDate) dateFilter.lte = new Date(endDate);

    const whereClause: any = {
      ...(Object.keys(dateFilter).length > 0 && { date: dateFilter }),
      ...(periodId && {
        section: {
          class: {
            periodId: periodId
          }
        }
      })
    };

    const attendances = await prisma.attendance.findMany({
      where: whereClause,
      include: {
        student: true,
        section: {
          include: {
            class: {
              include: {
                period: true
              }
            }
          }
        }
      },
      orderBy: {
        date: 'desc'
      }
    });

    const attendanceByStatus = await prisma.attendance.groupBy({
      by: ['status'],
      where: whereClause,
      _count: {
        id: true
      }
    });

    const attendanceByDate = await prisma.attendance.groupBy({
      by: ['date'],
      where: whereClause,
      _count: {
        id: true
      },
      orderBy: {
        date: 'asc'
      }
    });

    return NextResponse.json({
      attendances: attendances.map(attendance => ({
        id: attendance.id,
        date: attendance.date,
        status: attendance.status,
        reason: attendance.reason,
        student: {
          firstName: attendance.student.firstName,
          lastName: attendance.student.lastName,
          cedula: attendance.student.cedula,
          admissionNumber: attendance.student.admissionNumber
        },
        section: {
          name: attendance.section.name,
          className: attendance.section.class.name,
          classCode: attendance.section.class.code,
          periodName: attendance.section.class.period.name
        }
      })),
      summary: {
        totalRecords: attendances.length,
        byStatus: attendanceByStatus.map(item => ({
          status: item.status,
          count: item._count.id
        })),
        byDate: attendanceByDate.map(item => ({
          date: item.date,
          count: item._count.id
        }))
      }
    });
  } catch (error) {
    console.error('Error in attendance report:', error);
    throw error;
  }
}

// Reporte de inscripciones
async function getEnrollmentsReport(periodId: string | null) {
  try {
    const whereClause = periodId ? {
      section: {
        class: {
          periodId: periodId
        }
      }
    } : {};

    const enrollments = await prisma.studentEnrollment.findMany({
      where: whereClause,
      include: {
        student: true,
        section: {
          include: {
            class: {
              include: {
                period: true
              }
            }
          }
        }
      },
      orderBy: {
        createdAt: 'desc'
      }
    });

    const enrollmentsByStatus = await prisma.studentEnrollment.groupBy({
      by: ['isActive'],
      where: whereClause,
      _count: {
        id: true
      }
    });

    const enrollmentsBySection = await prisma.studentEnrollment.groupBy({
      by: ['sectionId'],
      where: whereClause,
      _count: {
        id: true
      }
    });

    return NextResponse.json({
      enrollments: enrollments.map(enrollment => ({
        id: enrollment.id,
        isActive: enrollment.isActive,
        createdAt: enrollment.createdAt,
        student: {
          firstName: enrollment.student.firstName,
          lastName: enrollment.student.lastName,
          cedula: enrollment.student.cedula,
          admissionNumber: enrollment.student.admissionNumber
        },
        section: {
          name: enrollment.section.name,
          className: enrollment.section.class.name,
          classCode: enrollment.section.class.code,
          periodName: enrollment.section.class.period.name
        }
      })),
      summary: {
        totalEnrollments: enrollments.length,
        byStatus: enrollmentsByStatus.map(item => ({
          isActive: item.isActive,
          count: item._count.id
        })),
        bySectionCount: enrollmentsBySection.length
      }
    });
  } catch (error) {
    console.error('Error in enrollments report:', error);
    throw error;
  }
}

// Reporte de clases
async function getClassesReport(periodId: string | null) {
  try {
    const whereClause = periodId ? { periodId } : { isActive: true };

    const classes = await prisma.class.findMany({
      where: whereClause,
      include: {
        period: true,
        sections: {
          include: {
            studentEnrollments: {
              where: {
                isActive: true
              }
            },
            teacherAssignments: {
              where: {
                isActive: true
              },
              include: {
                teacher: true
              }
            }
          }
        }
      },
      orderBy: {
        name: 'asc'
      }
    });

    const classesWithStats = classes.map(classItem => {
      const totalSections = classItem.sections.length;
      const totalStudents = classItem.sections.reduce((sum, section) => 
        sum + section.studentEnrollments.length, 0
      );
      const totalTeachers = classItem.sections.reduce((sum, section) => 
        sum + section.teacherAssignments.length, 0
      );

      return {
        id: classItem.id,
        name: classItem.name,
        code: classItem.code,
        description: classItem.description,
        isActive: classItem.isActive,
        period: {
          name: classItem.period.name,
          isActive: classItem.period.isActive
        },
        totalSections,
        totalStudents,
        totalTeachers,
        sections: classItem.sections.map(section => ({
          name: section.name,
          studentsCount: section.studentEnrollments.length,
          teachersCount: section.teacherAssignments.length,
          teachers: section.teacherAssignments.map(assignment => ({
            firstName: assignment.teacher.firstName,
            lastName: assignment.teacher.lastName
          }))
        }))
      };
    });

    return NextResponse.json({
      classes: classesWithStats,
      summary: {
        totalClasses: classes.length,
        totalSections: classesWithStats.reduce((sum, c) => sum + c.totalSections, 0),
        totalStudents: classesWithStats.reduce((sum, c) => sum + c.totalStudents, 0),
        averageStudentsPerClass: classes.length > 0 ? classesWithStats.reduce((sum, c) => sum + c.totalStudents, 0) / classes.length : 0
      }
    });
  } catch (error) {
    console.error('Error in classes report:', error);
    throw error;
  }
}