#include <stdio.h>
#include <string.h>
#include <stdlib.h>


struct Courses{
    int id;
    int credit_Hrs;
    char name[7];
};

struct student{
    int id;
    char name[100];
    int totalCourses;
    struct Courses courseList[4];
};

int displayMenu()
{
    int option = 0;

    printf("Choose from the following options:\n");
    printf("\t1- Add a new student\n");
    printf("\t2- Add/Delete a Courses\n");
    printf("\t3- Search for a student\n");
    printf("\t4- Print fee invoice\n");
    printf("\t0- Exit program\n");
    printf("\nEnter your selection: ");
    scanf("%d", &option);

    return option;
}

struct Courses courseCreation(int id, char* name, int credit_Hrs){

    struct Courses course;

    course.id = id;
    strcpy(course.name, name);
    course.credit_Hrs = credit_Hrs;

    return course;
}

void printCourses(struct Courses c)
        {
          printf("\t\t%d\t %s\t %d\n", c.id, c.name, c.credit_Hrs);
        }

void displayStudents(struct student s)
{
    printf("The details of the students are as follows:\n");
    printf("Name: %s\n", s.name);
    printf("\nCourses: ");

    int i = 0;

    for (i = 0;i<s.totalCourses;i++)

    {
        //call the function printCourses() to print the
        //courses
        printCourses(s.courseList[i]);
    }
}

void printFee(struct student s) //displayInvoice
{
    float totalHours = 0;
    float total = 0;

    printf("\n\tVALENCE COMMUNITY COLLEGE\n");
    printf("\tORLANDO FL 10101\n");
    printf("\t---------------------\n\n");
    printf("\tFee Invoice prepared for Student: \n");
    printf("\t%d-%s\n\n", s.id, s.name);
    printf("\t1 Credit hour = $ 120.25\n\n");
    printf("\tCRN\tCR_PREFIX\tCR_HOURS\n");
    for (int i = 0;i<s.totalCourses;i++)
    {
        totalHours =(float) s.courseList[i].credit_Hrs*(120.25);
        printf("\t%d\t %s\t %d\t $ %.2f\n", s.courseList[i].id, s.courseList[i].name, s.courseList[i].credit_Hrs, totalHours);
        total = total + totalHours;
    }
    printf("\n\t\tHealth & id fees\t $ 35.00\n");
    total = total + 35;
    printf("\t---------------------------------------\n");
    printf("\t\tTotal Payments\t $ %.2f\n", total);
}

void search_student(struct student s[], int size){
    int id, found = 0;

    printf("Enter the id of the student: ");
    scanf("%d", &id);

    int i;


    for (i = 0;i<size;i++)
    {
        //if the student is present,
        if (s[i].id == id)
        {
            //then print the details
            //using displayStudents()
            displayStudents(s[i]);
            found = 1;

            break;
        }
    }
    if (found == 0)
    {
        printf("\nNo Student Found!\n");
    }
}

void checkForNewInvoice(struct student s)

{
    char ch = 'n';

    printf("\nWant to display the new invoice(Y/N): ");
    scanf("%c", &ch);

    if (ch == 'Y' || ch == 'y')
    {
        printFee(s);
    }
}


void add_del_course(struct student studentList[],

                    int size_s, struct Courses course_list[], int size_c)

{
    int sid;

    printf("\nEnter the student's id: ");
    scanf("%d", &sid);

    //get the index value i of the student with the id
    int i = 0;

    for (i = 0;i<size_s;i++)
    {
        if (studentList[i].id == sid)
        {
            break;
        }
    }

    printf("\nHere are the courses [%s] is taking:", studentList[i].name);
    printf("\n\t\tCRN\tPREFIX\tCR. HOURS\n");

    int k;

    for (k = 0; k<studentList[i].totalCourses;k++)
    {
        printCourses(studentList[i].courseList[k]);
    }

    int numOfCourses = studentList[i].totalCourses;

    char choice = 'C';

    scanf("%c", &choice);

    printf("\nChoose from:\n");

    printf("A. Add a new Courses for [%s] \n", studentList[i].name);

    printf("D. Delete a Courses from [%s]'s schedule\n", studentList[i].name);

    printf("C. Cancel operation\n");

    printf("\nEnter your selection: ");

    choice = getchar();


    int c_id,l = 0, j = 0;

    switch (choice)
    {
        //if the user want to add a course

        case 'A':
        case 'a':
            if (studentList[i].totalCourses < 4)
            {
                printf("\nEnter the Courses id: ");
                scanf("%d", &c_id);

                for (l = 0; l<size_c; l++)
                {
                    //if the course are present,
                    //then add the course to the course list of the student
                    if (course_list[l].id == c_id)
                    {
                        studentList[i].courseList[numOfCourses] = course_list[l];
                        studentList[i].totalCourses++;

                        break;
                    }
                }
                //check whether the user want to print a new invoice
                //using the function checkForNewInvoice()
                checkForNewInvoice(studentList[i]);
            }
            else
            {
                printf("\nNo more courses can be added.\n");
            }

            break;
            //if the user want to delete a course

        case 'D':

        case 'd':

            printf("Enter Courses number to delete: ");
            scanf("%d", &c_id);

            getchar();

            //search for the course in the list
            for (l = 0;l<numOfCourses;l++)
            {
                //if present,
                if (studentList[i].courseList[l].id == c_id)
                {
                    //print the deleted course id and name.
                    printf("\n[%d %s] ", studentList[i].courseList[l].id, studentList[i].courseList[l].name);

                    for (j = l;j<numOfCourses - 1;j++)
                    {
                        studentList[i].courseList[j] = studentList[i].courseList[j + 1];
                    }

                    break;
                }
            }

            studentList[i].totalCourses--;

            printf("is deleted Sucessfully!\n\n");

            checkForNewInvoice(studentList[i]);

            break;

        case 'C':

        case 'c':

            break;

        default:

            printf("\nInvalid choice.\n");

    }

}

//definition of the function addStudent()

//this function takes array of student objects,

//array of Courses object and their sizes

//adds a student to the list.

struct student addStudent(struct student studentList[], int size,

                          struct Courses course_list[], int size_c)

{
    //create and allocate memory to a student object

    struct student* newStudent = (struct student*)malloc(sizeof(struct student));

    //declare the variables

    int i,found = 1;

    int no_courses = 0;

    char c;

    //read the student id.

    printf("\nEnter the student's id: ");
    scanf("%d", &newStudent->id);

    //Check if the student is alread present in the list

    while (found == 1 && size != 0)
    {

        int j = 0;

        for (j = 0; j< size; j++)
        {
            if (studentList[j].id == newStudent->id)
            {
                printf("The Id already exists.");
                printf("Enter the student's id: ");
                scanf("%d", &newStudent->id);
                found = 1;

                break;
            }
            found = 0;
        }
    }
    scanf("%c", &c);

    //read the student name

    printf("Enter student's name: ");
    c = getchar();

    i = 0;

    //assign the name to the student

    while (c != '\n')
    {
        newStudent->name[i] = c;

        c = getchar();

        i++;

    }

    newStudent->name[i] = '\0';

    printf("\nEnter how many courses (%s) is taking (up to 4 courses)?\n\t", newStudent->name);
    scanf("%d", &no_courses);

    while (no_courses > 4 || no_courses < 0)
    {
        printf("\nPlease enter a valid number (0-4)\n\t");
        scanf("%d", &no_courses);
    }

    newStudent->totalCourses = no_courses;

    int wrongCourse = 0;
    int courseIds[4];

    while (wrongCourse == 0)
    {
        i = 0;

        printf("\nEnter the %d Courses numbers\n\t", no_courses);
        //read the courses
        while (i < no_courses)
        {
            scanf("%d", &(courseIds[i]));
            i++;
        }
        int p;

        for (p = 0;p<no_courses;p++)
        {
            wrongCourse = 0;

            int q;

            for (q = 0;q<size_c;q++)
            {
                if (courseIds[p] == course_list[q].id)
                {
                    newStudent->courseList[p] = course_list[q];
                    wrongCourse = 1;
                    break;
                }
            }
            if (wrongCourse == 0)
            {
                printf("Wrong Crn entered.\n");
                break;
            }
        }
    }
    return *newStudent;
}

int main()
{
    struct Courses c_List[8];
    struct student students[100];
    int numOfStudents = 0;
    int id;

    c_List[0] = courseCreation(4587, "MAT 236", 4);
    c_List[1] = courseCreation(4599, "COP 220", 3);
    c_List[2] = courseCreation(8997, "GOL 124", 1);
    c_List[3] = courseCreation(9696, "COP 100", 3);
    c_List[4] = courseCreation(1232, "MAC 531", 5);
    c_List[5] = courseCreation(9856, "STA 100", 2);
    c_List[6] = courseCreation(8520, "TNV 400", 5);
    c_List[7] = courseCreation(8977, "CMP 100", 1);

    int i = 0;

    printf("Welcome!\n");


    int choice = displayMenu();
    while (choice != 0)
    {
        switch (choice)
        {
            case 1:
                students[numOfStudents] = addStudent(students, numOfStudents, c_List, 7);
                numOfStudents++;

                printf("\nStudent added successfully!\n");
                break;

            case 2:
                add_del_course(students, numOfStudents, c_List, 7);
                break;

            case 3:
                search_student(students, numOfStudents);
                break;

            case 4:
                printf("Enter the student's Id: ");
                scanf("%d", &id);
                for (i = 0;i<numOfStudents;i++)
                {
                    if (id == students[i].id)
                    {
                        printFee(students[i]);
                    }
                }
                break;

            default:
                printf("\nPlease enter a valid choice.\n");
        }
        printf("\n--------------------\n\n");
        choice = displayMenu();
    }
    printf("\nGoodbye!\n");

    return 0;
}