#include <stdbool.h>
#include <stdio.h>
#define MAXSTUDENTS 15

typedef struct {
  int crn;
  int hours;
  char* prefix;
} course_t;
typedef struct {
  char name[50];
  int id;
  int nCourses;
  course_t courses[4];
  struct student* next;
} student_t;
student_t students[MAXSTUDENTS];  // make array of students

void addStudent(void) {
  student_t new;
  for (int c = 0; c < 4; c++) new.courses[c].crn = 0;
  int tempIDstorage;
  printf("\nEnter the student's id: ");
  scanf("%d", &tempIDstorage);
  getchar();
  for (int c = 0; c < MAXSTUDENTS; c++)
    if (students[c].id == tempIDstorage) {
      printf("\nSorry, a student with that ID already exists!\n");
      return;
    }
  new.id = tempIDstorage;
  printf("\nEnter student's name: ");
  fgets(new.name, sizeof(new.name), stdin);
  new.name[strcspn(new.name, "\n")] = 0;
  printf("\nEnter how many courses [%s] is taking (up to 4)?\n\t", new.name);
  scanf("%d", &(new.nCourses));
  while (new.nCourses < 0 || new.nCourses > 4) {
    printf("Invalid input! Try again: ");
    scanf("%d", &(new.nCourses));
  }
  if (new.nCourses == 0) goto end;
  char yn;
  printf("\nDisplay list of courses? Y = yes, anything else = no\n\t");
  scanf(" %c", &yn);
  fflush(stdin);
  if (yn == 'y' || yn == 'Y') printCourseList();
  printf("\nEnter the student's %d course number(s):\n\t", new.nCourses);
  for (int c = 0; c < new.nCourses; c++) {
    scanf("%d", &(new.courses[c].crn));
    if (!crnCorrect(new.courses[c].crn)) {
      printf("Invalid crn(s)!");
      return;
    }
  }
end:
  for (int c = 0; c < MAXSTUDENTS; c++) {
    if (students[c].id == 0) students[c] = new;
    printf("\nStudent added successfully!\n");
    return;
  }
  printf("\nSorry - maximum number of students (%d) reached. \n", MAXSTUDENTS);
  printf(" Student not added\n");
}