#include <iostream>
#include "QueueT.h"

//typedef int QueueDataT;

struct QueueNodeT{
     QueueDataT data;
     QueueNodeT * next;
};

QueueT::QueueT(){
    size = 0;
    front = nullptr;
    rear = nullptr;
}

void DeleteQueue(QueueNodeT * & front) {
   QueueNodeT * tmp;
   while(front != nullptr) {
       tmp = front;
       front = front->next;
       delete tmp;
   }
}

void CopyQueue(QueueNodeT * & front, QueueNodeT * & rear, QueueNodeT * src) {
    QueueNodeT * trace;
    QueueNodeT * tmp;
    rear = nullptr;
    front = nullptr;

    trace = src;
    while (trace != nullptr) {
        tmp = new QueueNodeT;
        tmp->next = nullptr;
        tmp->data = trace->data;
        if (rear == nullptr) {
            front = tmp;
            rear = tmp;
        } else {
            rear->next = tmp;
            rear = tmp;
        }
        trace = trace->next;
    }
}

QueueT::QueueT(const QueueT & src){
    CopyQueue(front, rear, src.front);
    size = src.size;
}

QueueT::~QueueT(){
    DeleteQueue(front);
    rear = nullptr;
    size = 0;
}

QueueT & QueueT::operator=(const QueueT & src){
    if (this != & src) {
        DeleteQueue(front);
        CopyQueue(front, rear, src.front);
        size = src.size;
    }
    return * this;
}


void QueueT::Enqueue(QueueDataT data){
    QueueNodeT * tmp;

    tmp = new QueueNodeT;
    tmp->data = data;
    tmp->next = nullptr;

    if (rear == nullptr) {
        front = tmp;
        rear = tmp;
    } else {
        rear->next = tmp;
        rear = tmp;
    }
    size++;
}

void QueueT::Dequeue(){
    QueueNodeT * tmp;
    if (front != nullptr) {
       tmp = front;
       front = front->next;
       delete tmp;

       if (front == nullptr) {
           rear = nullptr;
       }

       size --;
    }
}

QueueDataT QueueT::Front(void) const{
    QueueDataT data{0};
    if (front != nullptr) {
       data = front->data;
    }

    return data;
}

size_t QueueT::Size(void) const{
    return size;
}