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

float avg;
typedef struct Node
{
    char name[100];
    int age, emp_num;
    char date[10];
    float salary;
    struct Node *next;
} Node;

Node *getNode()
{
    Node *p;
    p = (Node *)malloc(sizeof(Node));

    return p;
}

typedef struct
{
    int count;
    Node *first;
} list;

void Display_all(list *lp)
{
    struct Node *temp;
    if (lp->first == NULL)
    {
        printf("There Are No Employee Details!!\n");
        return;
    }
    temp = lp->first;
    printf("-----------All Employee Details-----------\n");
    while (temp != NULL)
    {
        printf("Employee Name :: %s\n", temp->name);
        printf("Age :: %d\n", temp->age);
        printf("Emp Number :: %d\n", temp->emp_num);
        printf("Joining Date :: %s\n", temp->date);
        printf("Salary :: %f\n", temp->salary);
        printf("\n");
        temp = temp->next;
    }
    printf("Total Number of Employees :: %d", lp->count);
}

void Display_particular(list *lp)
{
    struct Node *temp;
    int emp_num;
    if (lp->first == NULL)
    {
        printf("There Are No Employee Details!!\n");
        return;
    }
    printf("Enter the Employee number whose Deatils are to be displayed :: ");
    scanf("%d", &emp_num);
    temp = lp->first;
    while (temp != NULL)
    {
        if (temp->emp_num == emp_num)
        {
            printf("Employee Name :: %s\n", temp->name);
            printf("Age :: %d\n", temp->age);
            printf("Emp Number :: %d\n", temp->emp_num);
            printf("Joining Date :: %s\n", temp->date);
            printf("Salary :: %f\n", temp->salary);
            printf("\n");
            return;
        }
        temp = temp->next;
    }
    printf("Employee not found!!!\n");
}
void Delete_record(list *lp)
{
    struct Node *temp, *prev;
    int emp_num;
    if (lp->first == NULL)
    {
        printf("There Are No Employees To be deleted!!\n");
        return;
    }
    temp = lp->first;
    printf("Enter the Employee number whose Record is to be Deleted :: ");
    scanf("%d\n", &emp_num);

    if (temp->emp_num == emp_num)
    {
        lp->first = temp->next;
        avg = ((avg*lp->count)-temp->salary)/(lp->count-1);
        free(temp);
        lp->count--;
        printf("Record Deleted Successfully!!\n");
        return;
    }
    while (temp != NULL)
    {
        if (temp->emp_num != emp_num)
        {
            prev = temp;
            temp = temp->next;
        }
        else
        {
            if (temp->next != NULL)
            {
                prev->next = temp->next;
                avg = ((avg*lp->count)-temp->salary)/(lp->count-1);
                free(temp);
                lp->count--;
                printf("Record Deleted Successfully!!\n");
                return;
            }
            else
            {
                prev->next = NULL;
                avg = ((avg*lp->count)-temp->salary)/(lp->count-1);
                free(temp);
                lp->count--;
                printf("Record Deleted Successfully!!\n");
                return;
            }
        }
    }
    printf("Employee Not Found!!!\n");
}

void Insert_record(list *lp)
{
    char name[100];
    int age, emp_num;
    char date[10];
    float salary;
    printf("Enter Employee Name :: ");
    scanf("%s", name);
    printf("Enter Employee Age :: ");
    scanf("%d", &age);
    printf("Enter Employee Number :: ");
    scanf("%d", &emp_num);
    printf("Enter Date of Joining :: ");
    scanf("%s", date);
    printf("Enter Salary :: ");
    scanf("%f", &salary);

    Node *employee;
    employee = getNode();
    strcpy(employee->name, name);
    employee->age = age;
    employee->emp_num = emp_num;
    strcpy(employee->date, date);
    employee->salary = salary;
    employee->next = NULL;

    if (lp->first == NULL)
    {
        lp->first = employee;
        printf("Employee Records Inserted Successfully!!!\n");
        lp->count++;
        avg = ((avg*(lp->count-1))+employee->salary)/(lp->count);
        return;
    }
    struct Node *temp;
    temp = lp->first;
    while (temp->next != NULL)
    {
        temp = temp->next;
    }
    temp->next = employee;
    printf("Employee Records Inserted Successfully!!!\n");
    lp->count++;
    avg = ((avg*(lp->count-1))+employee->salary)/(lp->count);
}

void Display_salary_above_average(list *lp)
{
    struct Node *temp;
    if (lp->first == NULL)
    {
        printf("There Are No Employee Details!!\n");
        return;
    }
    temp = lp->first;
    printf("-----------Employee Details whose Salaray is above Average-----------\n");
    while (temp != NULL)
    {
        if (temp->salary > avg)
        {
            printf("Employee Name :: %s\n", temp->name);
            printf("Age :: %d\n", temp->age);
            printf("Emp Number :: %d\n", temp->emp_num);
            printf("Joining Date :: %s\n", temp->date);
            printf("Salary :: %f\n", temp->salary);
            printf("\n");
        }
        temp = temp->next;
    }
}

int main()
{
    printf("-------------EMPLOYEE MANAGEMENT SYSTEM-------------\n");
    int choice;
    list employee;
    employee.first = NULL;
    employee.count = 0;
    avg = 0.0;
    while (1)
    {
        printf("\n");
        printf("Press 1 to Display Records of all Employees\n");
        printf("Press 2 to Display Record of a particular Employee\n");
        printf("Press 3 to Delete Record of a particular\n");
        printf("Press 4 to Insert Record of a new Employee\n");
        printf("Press 5 to Display name of Employees having highest salary than average of all employees salaray\n");
        printf("Press 6 to Exit the program\n");
        printf("Enter your choice :: ");
        scanf("%d", &choice);

        switch (choice)
        {
        case 1:
            Display_all(&employee);
            break;
        case 2:
            Display_particular(&employee);
            break;
        case 3:
            Delete_record(&employee);
            break;
        case 4:
            Insert_record(&employee);
            break;
        case 5:
            Display_salary_above_average(&employee);
            break;
        case 6:
            exit(0);
        default:
            printf("Invaild Choice !!!\n");
        }
    }
    return 0;
}