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

using namespace std;

struct StackRecordT{
   ItemT data;
   StackRecordT * next;
};

StackT::StackT() {
   size = 0;
   top = nullptr;
}

void DeleteList(StackRecordT * top) {
      StackRecordT * tmp{top};
      while(top != nullptr) {
          tmp = top;
          top=top->next;
          delete tmp;
      }
}

StackRecordT * CopyList(StackRecordT * top) {
    StackRecordT * current{top};

    StackRecordT * tmp{nullptr}, 
                 * follow{nullptr},
                 * head{nullptr};

    for(current = top; current != nullptr; current = current->next) {
          tmp = new StackRecordT;
          tmp->data = current->data;
          tmp->next = nullptr;

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

    return head;
}

StackT::StackT(const StackT & other) {
    cout << "In the copy constructor " << endl;
    size = other.size;
    top = CopyList(other.top);
}


StackT::~StackT(){
    DeleteList(top);
    top = nullptr;
    size = 0;
}

StackT & StackT::operator = (const StackT & other){


    if (this != &other) {
        DeleteList(top);
        top = CopyList(other.top);
        size = other.size;
    }

    return *this;
}



void StackT::Push(ItemT newData){
   StackRecordT * tmp{new StackRecordT};

   if (tmp != nullptr) {
       tmp->data = newData;
       tmp->next = top; 
       top = tmp;

       ++size;
   }

}

void StackT::Pop(void){

     if (nullptr != top) {
         StackRecordT * tmp{top};
         top = top -> next;
         delete tmp;
         tmp = nullptr;
         --size;
     } else {
         cerr <<"Error, attempt to pop an empty stack." << endl;
     }

}

ItemT StackT::Top(void) const{
     ItemT rv{DEFAULT_ITEM_T};

     if (nullptr != top) {
         rv = top->data;
     } else {
         cerr <<"Error, attempt to top an empty stack." << endl;
     }

     return rv;
}

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