/* ALEXANDROS AGRAFIOTIS, ECE UTH, 12/01/2021 */
/* This program sorts students to classes based on their age */

#include"lab10.h"
#include <stdio.h>
#include <stdlib.h>

/* Returns the count of a specified age found in students' array */
int print_count_of_age (const student_t students_array[], const int num_students,const int age) {
    int count=0,i;

    for(i=0; i<num_students; i++){
        if(age == students_array[i].age){
            count++;
        }
    }
    return count;
}

void print_student_info(const student_t students_array[],const int num_students, const int min_age, const int max_age){
    int i, serial_num,count;

    /* Print student's serial number, name and age */
    for(i=0; i< num_students; i++){
        serial_num = (int)(&students_array[i]-&students_array[0]);
        printf("%d. %s - %d\n",serial_num,students_array[i].name, students_array[i].age);
    }
    /* Print count of every age in students' array */
    for(i=min_age; i<= max_age; i++){
        count = print_count_of_age(students_array, num_students, i);
        printf("Age %d: %d students\n",i,count);
    }
}

void sort_students_to_classes(class_t classes_array[], const int num_classes,student_t students_array[], const int num_students, const int min_age){
    int i,j,pointer_count;

    for(i=1; i<=num_classes; i++){
        classes_array[i-1].level = i;
    }

    /* Instantiate all pointers-to-students to NULL */
    for(i=1; i<= num_classes; i++){
        for(j=0; j<num_students; j++){
            classes_array[i-1].pstudents[j] = NULL;
        }
    }

    /* For each class, check if every student's age corresponds to the age of the class. If it does, set pointer towards student */
    for(i=1; i <= num_classes; i++){
        pointer_count = 0;
        for(j=0; j<num_students; j++){
            if(students_array[j].age == min_age + i - 1){
                classes_array[i-1].pstudents[pointer_count] = &students_array[j];
                pointer_count++;
            }
        }
    }
}

void print_sorted_classes(const class_t class, const int max_students){
    int i;

    printf("== %d ==\n", class.level);

    for(i=0; i<max_students; i++){
        if(class.pstudents[i] == NULL){
            break;
        }
        printf("%s\n", class.pstudents[i]->name);
    }
}


int main (int argc, char *argv[]) {

    class_t classes_array[NUM_CLASSES];
    student_t students_array[MAX_STUDENTS];
    int num_students,i;

    if(argc == 1 || argc > 2 || atoi(argv[1]) > MAX_STUDENTS ){
        printf("Incorrect arguments!\n");
        return 1;
    }

    num_students = atoi(argv[1]);

    /*Instantiate students array with generate_students function */
    generate_students(students_array, MAX_STUDENTS,num_students, MIN_AGE, MAX_AGE, MAX_NAME_SIZE);

    print_student_info(students_array, num_students, MIN_AGE, MAX_AGE);

    sort_students_to_classes(classes_array, NUM_CLASSES, students_array, num_students, MIN_AGE);

    for(i=0; i<NUM_CLASSES; i++){
        print_sorted_classes(classes_array[i], print_count_of_age(students_array, num_students, MIN_AGE+i));
    }

    return 0;
}