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

// structure of a node in the list
struct node
{
    int id;
    char name[50];
    long phone;
    char date[10];
    struct node *next;
};

// function to insert a new node at the appropriate position
void insert(struct node **head_ref, int new_id, char new_name[], long new_phone, char new_date[])
{
    struct node *new_node = (struct node *)malloc(sizeof(struct node));
    new_node->id = new_id;
    strcpy(new_node->name, new_name);
    new_node->phone = new_phone;
    strcpy(new_node->date, new_date);
    struct node *current;
    // if list is empty
    if (*head_ref == NULL)
    {
        new_node->next = *head_ref;
        *head_ref = new_node;
    }
    // if the id of new node is less than the id of first node, insert new node at the start
    else if (new_node->id < (*head_ref)->id)
    {
        new_node->next = *head_ref;
        *head_ref = new_node;
    }
    else
    {
        // else traverse the list and insert the new node at the appropriate position
        current = *head_ref;
        while (current->next != NULL && current->next->id < new_node->id)
        {
            current = current->next;
        }
        new_node->next = current->next;
        current->next = new_node;
    }
}

// function to remove a node from the list
void removee(struct node **head_ref, int id)
{
    // if list is empty
    if (*head_ref == NULL)
        return;
    // store head node
    struct node *temp = *head_ref, *prev;
    // if head needs to be removed
    if (temp != NULL && temp->id == id)
    {
        *head_ref = temp->next;
        free(temp);
        return;
    }
    // search for the id to be deleted and keep track of previous node
    while (temp != NULL && temp->id != id)
    {
        prev = temp;
        temp = temp->next;
    }
    // if id is not present in the list
    if (temp == NULL)
        return;
    // unlink the node from the list
    prev->next = temp->next;
    free(temp);
}

// function to update a node
void update(struct node *head_ref, int id, char new_name[], long new_phone, char new_date[])
{
    // if list is empty
    if (head_ref == NULL)
        return;
    // traverse the list and search for the id to be updated
    while (head_ref != NULL)
    {
        if (head_ref->id == id)
        {
            strcpy(head_ref->name, new_name);
            head_ref->phone = new_phone;
            strcpy(head_ref->date, new_date);
        }
        head_ref = head_ref->next;
    }
}

// function to search for a node
void search(struct node *head_ref, int id)
{
    // if list is empty
    if (head_ref == NULL)
        return;
    // traverse the list and search for the id
    while (head_ref != NULL)
    {
        if (head_ref->id == id)
        {
            printf("\nPatient ID\tPatient Name\tPhone number\tAppointment date\n");
            printf("%d\t\t%s\t\t%ld\t\t%s\n", head_ref->id, head_ref->name, head_ref->phone, head_ref->date);
        }
        head_ref = head_ref->next;
    }
}

// function to print the list
void printList(struct node *node)
{
    // if list is empty
    if (node == NULL)
    {
        printf("List is empty");
        return;
    }
    // traverse the list and print the content of each node
    printf("Patient ID\tPatient Name\tPhone number\tAppointment date\n");
    while (node != NULL)
    {
        printf("%d\t\t%s\t\t%ld\t\t%s\n", node->id, node->name, node->phone, node->date);
        node = node->next;
    }
}

int main()
{
    struct node *head = NULL;
    int choice, id;
    char name[50];
    long phone;
    char date[10];

    while (1)
    {
        printf("\n*** Medical Appointment System for Pusat Kesihatan Universiti UTHM ***\n\n");
        printf("1. Insert\n");
        printf("2. Remove\n");
        printf("3. Update\n");
        printf("4. Find\n");
        printf("5. List All Records\n");
        printf("6. Exit\n\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
        // perform the appropriate operation based on the choice
        switch (choice)
        {
        case 1:
            printf("Enter the patient id: ");
            scanf("%d", &id);
            printf("Enter the patient name: ");
            scanf("%s", name);
            printf("Enter the patient phone number: ");
            scanf("%ld", &phone);
            printf("Enter the patient date: ");
            scanf("%s", date);
            insert(&head, id, name, phone, date);
            printf("\nInserted Sccessfully\n\n");
            break;
        case 2:
            printf("Enter the patient id to be deleted: ");
            scanf("%d", &id);
            removee(&head, id);
            printf("\nDeleted Sccessfully\n\n");
            break;
        case 3:
            printf("Enter the patient id to be updated: ");
            scanf("%d", &id);
            printf("Enter the patient name: ");
            scanf("%s", name);
            printf("Enter the patient phone number: ");
            scanf("%ld", &phone);
            printf("Enter the patient date: ");
            scanf("%s", date);
            update(head, id, name, phone, date);
            printf("\nUpdated Sccessfully\n\n");
            break;
        case 4:
            printf("Enter the patient id to be searched: ");
            scanf("%d", &id);
            search(head, id);
            printf("\n\n");
            break;
        case 5:
            printList(head);
            printf("\n\n");
            break;
        case 6:
            exit(0);
        default:
            printf("Wrong input, please try again..\n");
        }
    }
    return 0;
}