export default function (data) {
  // your code starts here
  // console.log(data.grades)
  const graduateStudents = [];
  const nonGraduateStudents = [];

  data.students.forEach(student => {
      const studentGrades = data.grades.filter(gr => gr.studentId === student.id || gr.studentName === student.name);
      const studentExams = data.exams.filter(ex => ex.studentId === student.id || ex.studentName === student.name);

      if(studentExams.length < 2){
          nonGraduateStudents.push({
              id: student.id, 
              name: student.name,
              reason: 'exams'});
      }else{
          const gradeSum = studentGrades.reduce((sum, gr) => sum + gr.grade, 0);
          const examSum = studentExams.reduce((sum, ex) => sum + ex.grade, 0);
          const grAvg = gradeSum / studentGrades.length;
          const exAvg = examSum / studentExams.length;
          const totalGr = (grAvg * 0.4) + (exAvg * 0.6);

          if(totalGr >= data.passingGrade){
              graduateStudents.push({
                  id: student.id,
                  name: student.name,
                  grade: totalGr
              })
          }else{
              if(studentExams.length < 2 && totalGr < data.passingGrade){
                  nonGraduateStudents.push({
                      id: student.id,
                      name: student.name,
                      reason: 'score and exams'
                  });
              }else{
                  nonGraduateStudents.push({
                      id: student.id, 
                      name: student.name,
                      reason: 'score'
                  });
              }
          }
      }
  });
  return{
      name: data.course,
      graduates: graduateStudents,
      nonGraduates: nonGraduateStudents
  }
  // your code ends here
}