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

typedef struct {
    char id[20];
    char clas[20];
    char name[20];
    double score1, score2, score3, total, average;
} Student;

void displayMenu();
void inputStudents(Student students[], int *count);
void outputStudents(Student students[], int count);
void sortStudents(Student students[], int count);
void insertStudent(Student students[], int *count);
void deleteStudent(Student students[], int *count);
void modifyStudent(Student students[], int count);
void queryStudent(Student students[], int count);

int main() {
    Student students[100];
    int count = 0;
    char option;

    while (1) {
        displayMenu();
        printf("Please input your option: ");
        scanf(" %c", &option);

        switch (option) {
            case '1':
                inputStudents(students, &count);
                break;
            case '2':
                deleteStudent(students, &count);
                break;
            case '3':
                queryStudent(students, count);
                break;
            case '4':
                sortStudents(students, count);
                outputStudents(students, count);
                break;
            case '5':
                outputStudents(students, count);
                break;
            case '6':
                printf("Exiting system...\n");
                return 0;
            default:
                printf("Invalid option. Try again.\n");
        }
    }
    return 0;
}

void displayMenu() {
    printf("\n1. Input\n");
    printf("2. Delete\n");
    printf("3. Select\n");
    printf("4. Order\n");
    printf("5. Output\n");
    printf("6. Quit\n");
}

void inputStudents(Student students[], int *count) {
    char cont = 'y';
    while (cont == 'y') {
        printf("ID: ");
        scanf("%s", students[*count].id);
        printf("Class: ");
        scanf("%s", students[*count].clas);
        printf("Name: ");
        scanf("%s", students[*count].name);
        printf("Score1: ");
        scanf("%lf", &students[*count].score1);
        printf("Score2: ");
        scanf("%lf", &students[*count].score2);
        printf("Score3: ");
        scanf("%lf", &students[*count].score3);

        students[*count].total = students[*count].score1 + students[*count].score2 + students[*count].score3;
        students[*count].average = students[*count].total / 3.0;
        (*count)++;

        printf("Continue? (y/n): ");
        scanf(" %c", &cont);
    }
}

void outputStudents(Student students[], int count) {
    for (int i = 0; i < count; i++) {
        printf("%s %s %s %.1f %.1f %.1f %.1f\n", 
               students[i].id, students[i].clas, students[i].name, 
               students[i].score1, students[i].score2, students[i].score3, 
               students[i].total);
    }
}

void sortStudents(Student students[], int count) {
    for (int i = 0; i < count - 1; i++) {
        for (int j = i + 1; j < count; j++) {
            if (strcmp(students[i].clas, students[j].clas) > 0 || 
                (strcmp(students[i].clas, students[j].clas) == 0 && students[i].total < students[j].total)) {
                Student temp = students[i];
                students[i] = students[j];
                students[j] = temp;
            }
        }
    }
}

void insertStudent(Student students[], int *count) {
    Student newStudent;
    printf("ID: ");
    scanf("%s", newStudent.id);
    printf("Class: ");
    scanf("%s", newStudent.clas);
    printf("Name: ");
    scanf("%s", newStudent.name);
    printf("Score1: ");
    scanf("%lf", &newStudent.score1);
    printf("Score2: ");
    scanf("%lf", &newStudent.score2);
    printf("Score3: ");
    scanf("%lf", &newStudent.score3);

    newStudent.total = newStudent.score1 + newStudent.score2 + newStudent.score3;
    newStudent.average = newStudent.total / 3.0;

    for (int i = *count; i > 0; i--) {
        if (strcmp(students[i - 1].clas, newStudent.clas) < 0 || 
            (strcmp(students[i - 1].clas, newStudent.clas) == 0 && students[i - 1].total > newStudent.total)) {
            students[i] = students[i - 1];
        } else {
            students[i] = newStudent;
            (*count)++;
            return;
        }
    }
    students[0] = newStudent;
    (*count)++;
}

void deleteStudent(Student students[], int *count) {
    char idOrName[20];
    printf("Enter ID or Name to delete: ");
    scanf("%s", idOrName);

    for (int i = 0; i < *count; i++) {
        if (strcmp(students[i].id, idOrName) == 0 || strcmp(students[i].name, idOrName) == 0) {
            for (int j = i; j < *count - 1; j++) {
                students[j] = students[j + 1];
            }
            (*count)--;
            printf("Student deleted.\n");
            return;
        }
    }
    printf("Student not found.\n");
}

void modifyStudent(Student students[], int count) {
    char id[20];
    printf("Enter ID to modify: ");
    scanf("%s", id);

    for (int i = 0; i < count; i++) {
        if (strcmp(students[i].id, id) == 0) {
            printf("New ID: ");
            scanf("%s", students[i].id);
            printf("New Class: ");
            scanf("%s", students[i].clas);
            printf("New Name: ");
            scanf("%s", students[i].name);
            printf("New Score1: ");
            scanf("%lf", &students[i].score1);
            printf("New Score2: ");
            scanf("%lf", &students[i].score2);
            printf("New Score3: ");
            scanf("%lf", &students[i].score3);

            students[i].total = students[i].score1 + students[i].score2 + students[i].score3;
            students[i].average = students[i].total / 3.0;
            printf("Student modified.\n");
            return;
        }
    }
    printf("Student not found.\n");
}

void queryStudent(Student students[], int count) {
    char query[20];
    printf("Enter query (ID/Class/Name): ");
    scanf("%s", query);

    for (int i = 0; i < count; i++) {
        if (strstr(students[i].id, query) || strstr(students[i].clas, query) || strstr(students[i].name, query)) {
            printf("%s %s %s %.1f %.1f %.1f %.1f\n", 
                   students[i].id, students[i].clas, students[i].name, 
                   students[i].score1, students[i].score2, students[i].score3, 
                   students[i].total);
        }
    }
}