#include <iostream>
#include "CSListT.h"
#include <stdexcept>

using namespace std;

struct NodeT {
    ItemT data;
    NodeT * next{nullptr};
};

NodeT * CopyList(NodeT * head) {
     NodeT * newList{nullptr};
     NodeT * walker{head}, 
           * newWalker{nullptr};

     if (nullptr != head) {
         while (nullptr != walker) {
            NodeT * tmp = new NodeT;
            tmp->data = walker->data;
            tmp->next = nullptr;

            if (nullptr == newList) {
               newList = tmp;
            } else {
               newWalker->next = tmp;
            }
            newWalker = tmp;
            walker = walker->next;
         }
     }
     return newList;
}

ListT::ListT(const ListT & other) {
    head = CopyList(other.head);
    tail = head;
    for(tail = head; tail!= nullptr and tail->next != nullptr; tail =tail->next);
    size = other.size;
}

ListT::~ListT(){
    NodeT * tmp{head};
    while (nullptr != head) {
        head = head->next;
        delete tmp;
        tmp = head;

    }
}

void ListT::PushFront(ItemT i){
    NodeT * tmp{nullptr};

    tmp = new NodeT;
    tmp->data = i;
    tmp->next = nullptr;

    if (nullptr == head) {
        head = tmp;
        tail = tmp;
    } else {
        tmp->next = head;
        head = tmp;

    }
    ++size;
}

void ListT::PopFront(){
    NodeT * tmp{head};

    if (nullptr != head) {
       head = head->next;
       delete tmp;

       if (nullptr == head) {
          tail = nullptr;
       }
       --size;
    }
}

size_t ListT::Size() const{
    return size;
}

void ListT::Home(){
    ptr = head;
}
 
bool ListT::Next(){
    if (nullptr != ptr) {
       ptr = ptr-> next;
       return true;
    }
    return false;
}

bool ListT::AtEnd(){
    return nullptr == ptr;
}

ItemT & ListT::Data(){
    if (nullptr != ptr) {
       return ptr->data;
    }

    throw out_of_range{"Attempt to access an empty pointer."};
}