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

//Employee struct holds employee value
struct Employee{
    char firstName[256];
    char lastName[256];
    int age;
    int sinNumber;
    char status;
};

//Node struct holds an Employee struct as data and a next node
struct Node{
    struct Employee *employee;
    struct Node *next;
};

//initilizes the List
void initilizeList(struct Node** head){
    *head = (struct Node*) malloc(sizeof(struct Node));
    (*head)->next = NULL;
    (*head)->employee = (struct Employee*) malloc (sizeof(struct Employee));
}

//Given a list and the data of the new employee it adds it to the end of the list
void addEmployeeEnd(struct Node** head, char firstName[256], char lastName[256], int age, int sinNum, char status){
    struct Node *newNode;
    initilizeList(&newNode);

    //initialize the employee data
    strcpy(newNode->employee->firstName, firstName);
    strcpy(newNode->employee->lastName, lastName);
    newNode->employee->age = age;
    newNode->employee->sinNumber = sinNum;
    newNode->employee->status = status;

    //if the list is empty make it the first element
    if (*head == NULL){
        *head = newNode;
        return;
    }

    //navigate to the end of the list
    struct Node* current;
    for(current = *head;current->next!=NULL;current=current->next);

    //add newNode to the end of the list
    current->next = newNode;
}

//Given a list and the data of the new employee it adds it to the front of the list
void addEmployeeFront(struct Node** head, char firstName[256], char lastName[256], int age, int sinNum, char status){
    struct Node *newNode;
    initilizeList(&newNode);

    //initialize the employee data
    strcpy(newNode->employee->firstName, firstName);
    strcpy(newNode->employee->lastName, lastName);
    newNode->employee->age = age;
    newNode->employee->sinNumber = sinNum;
    newNode->employee->status = status;

    //if the list is empty make it the first element
    if (*head == NULL){
        *head = newNode;
        return;
    }

    //add it to the front of the list
    newNode->next = *head;
    *head = newNode;
}

/*
int getnode(){


}*/

//Removes an (single?) employee of the given lastName or SIN number
void removeEmployee(struct Node** head, char firstName [256], int sinNum){
    if (*head == NULL)
        return;
    struct Node* current = *head;
    struct Node* prev = current;
    struct Node* temp = NULL;
    do{
        //if one of the other is true don't need to check which one the user wants to use because they will not equal anywyas
        if (current->employee->sinNumber == sinNum || strcmp(current->employee->firstName, firstName) == 0){
            temp = current; //holds the node to be freed
            prev->next = current->next; //deletes the employee
            free(temp->employee);
            free(temp);
        }
        prev = current;
        current = current->next;
    }while(current->next!=NULL);
}

//Duplicates each nodes so that there is _times amount of each node
void Repeated(struct Node** head, int times){
    struct Node* current = *head;
    //holds the new list with the correct amount of each node
    struct Node* result;
    initilizeList(&result);
    result = NULL;


    while(current!=NULL){
        int i;
        //adds the current->employee to the end of the list _times
        for (i = 0;i<times;i++){
            addEmployeeEnd(&result, current->employee->firstName, current->employee->lastName, current->employee->age, current->employee->sinNumber, current->employee->status);
        }
        current=current->next;
    }
    *head = result;
}

//Deletes the entire list by free each element and settign _head to NULL
void deleteList(struct Node** head){
    struct Node* current = *head;
    struct Node* temp;
    while(current!=NULL){
        temp = current;
        current = current->next;
        free(temp->employee);
        free(temp);
        //temp=NULL;
    }
    *head = NULL;
}

//Deletes every elements except the ones with the given last name
void deleteExpt(struct Node** head, char lastName[256]){
    //used to hold the new list with only the elements with the given last name
    struct Node *newHead;
    initilizeList(&newHead);
    newHead = NULL;

    //used to hold the current position
    struct Node *current = *head;

    while(current!=NULL){
        if (strcmp(current->employee->lastName, lastName)==0){
            addEmployeeEnd(&newHead, current->employee->firstName, current->employee->lastName, current->employee->age, current->employee->sinNumber, current->employee->status);
        }
        current = current ->next;
    }
    //deletes old list
    deleteList(head);
    //changes the old list to be the new list
    *head = newHead;
}

//converts a linked list into a circular linked list
void toCircular(struct Node **head){
    struct Node* current = *head;
    if (*head == NULL)
        return;
    while(current->next!=NULL){
        current = current->next;
    }

    current ->next = *head;
}

//Splits a circular linked list into two circular linked lists with even elements with the extra going in the first section
void divideList (struct Node **source, struct Node** first, struct Node** second){
    struct Node* current = *source;

    int length = 0;
    while(current!=NULL){
        length++;
        current=current->next;
    }
    //length now contains the amount of elements in the list

    //if all elements are added to the first list
    if(length<2){
        *first = *source;
        *second = NULL;
    }
    else{
        //changes length so the first list has the extra element if needed
        length = (length -1)/2;

        current = *source;
        int i;
        //navigates untill the lengthth element which is where the lists are to be split
        for(i = 0;i<length;i++){
            current = current->next;
        }
        //first gets the whole list
        *first = *source;
        //second gets the list after current
        *second = current->next;
        //this splits the two lists
        current->next = NULL;
    }
}

//Displays all of the employess in the list
void displayList(struct Node *head){
    struct Node* current;
    for(current = head;current!=NULL;current=current->next)
        printf("First Name: %s\nLast Name: %s\nAge: %d\nSIN Number: %d\nStatus: %s\n\n", current->employee->firstName, current->employee->lastName, current->employee->age, current->employee->sinNumber, current->employee->status=='a'?"Active":(current->employee->status=='s'?"Suspended":"Terminated"));
    printf("\n");
}

//Displays all of the employees in the list that are older than _age
void displayList1(struct Node* head, int age){
    struct Node* current;
    for (current = head;current !=NULL; current= current->next){
        if (current->employee->age > age)
            printf("First Name: %s\nLast Name: %s\nAge: %d\nSIN Number: %d\nStatus: %s\n\n", current->employee->firstName, current->employee->lastName, current->employee->age, current->employee->sinNumber, current->employee->status=='a'?"Active":(current->employee->status=='s'?"Suspended":"Terminated"));
    }
    printf("\n");
}

//displays all of the employees in the list that have the same status as _status
void displayList2(struct Node* head, char status){
    struct Node* current = head;
    while(current !=NULL){
        if (current->employee->status == status)
            printf("First Name: %s\nLast Name: %s\nAge: %d\nSIN Number: %d\nStatus: %s\n\n", current->employee->firstName, current->employee->lastName, current->employee->age, current->employee->sinNumber, current->employee->status=='a'?"Active":(current->employee->status=='s'?"Suspended":"Retired"));
        current = current->next;
    }
    printf("\n");
}

int main (){
    //head of the employee records
    struct Node *head;
    initilizeList(&head);
    head= NULL;
    //used for user input
    int age;
    int sinNum;
    char firstName [256];
    char lastName [256];
    char status;

    char temp;//used to deal with scanfs extra 'enter' character

    //testing only
    addEmployeeFront(&head, "real", "person", 19, 9182, 'a');
    addEmployeeFront(&head, "foo", "bar", 22, 5555, 'a');
    addEmployeeFront(&head, "test", "erson", 55, 9911, 's');
    addEmployeeFront(&head, "forth", "toStart", 10, 6543, 't');
    //end

    int i;
    //loop to get user input for each employee and add them to the list
    for (i =1;;i++){
        printf("Enter the first name of Employee #%d. Enter 'q' to stop entering employees.\n", i);
        scanf("%s%c", firstName, &temp);
        //strcpy(firstName, "q");
        if (strcmp(firstName,"q")==0)
            break;

        printf("Enter his/her last name.\n");
        scanf("%s%c", lastName, &temp);

        printf("Enter his/her age\n");
        scanf("%d%c", &age, &temp);

        printf("Enter his/her SIN number\n");
        scanf("%d%c", &sinNum, &temp);

        printf("Enter the status of the employee 'a' active, 's' suspended, 't' terminated.\n");
        scanf("%c%c", &status, &temp);

        addEmployeeEnd(&head, firstName, lastName, age, sinNum, status);
    }

    printf("\nDisplaying all Employees in the List\n");
    displayList(head);

    printf("Displaying all Employees above the age of 50 in the List\n");
    displayList1(head, 50);
    printf("Displaying all Employees with the status of Active in the List\n");
    displayList2(head, 'a');

    int method;
    printf("To REMOVE an Employee from the list first select the criteria\n");
    printf("0 - Do not REMOVE an Employee\n");
    printf("1 - by first name\n");
    printf("2 - by SIN number\n");
    scanf("%d%c", &method, &temp);

    if (method ==1){
        printf("Enter the first name of the employee you would like to REMOVE\n");
        scanf("%s%c", firstName, &temp);
        removeEmployee(&head, firstName, -1);
    }
    else if (method == 2){
        printf("Enter the SIN number of the employee you would like to REMOVE\n");
        scanf("%d%c", &sinNum, &temp);
        removeEmployee(&head, NULL, sinNum);
    }

    displayList(head);

    int times;
    printf("Enter the number of times you would like the elements in the list to be repeated\n");
    scanf("%d%c", &times, &temp);

    Repeated(&head, times);

    displayList(head);

    printf("To REMOVE ALL Employees except for those with a specified last name enter 1\n");
    printf("0 - Do not REMOVE any Employees\n");
    printf("1 - specify last name and delete all other employees\n");
    scanf("%d%c", &method, &temp);

    if (method ==1){
        printf("Enter the last name name of the employee you would like to KEEP\n");
        scanf("%s%c", lastName, &temp);
        deleteExpt(&head, lastName);
    }

    displayList(head);

    //converts the list into a circular linked list
    printf("Now converting the linked list into a circular linked list\n");
    toCircular(&head);
    //two new lists to hold the front and back of the entire list head after it is divided
    struct Node* front = (struct Node*) malloc (sizeof(struct Node));
    struct Node* back = (struct Node*) malloc (sizeof(struct Node));

    //splits the double linked list head into the double linked lists front and back
    printf("Now splitting the circular linked list into two lists\n");
    divideList(&head, &front, &back);

    printf("\nDisplaying the Front List\n");
    displayList(front);
    printf("\nDisplaying the Back List\n");
    displayList(back);

    //free everything
    deleteList(&head);
    deleteList(&front);
    deleteList(&back);

    return 0;
}