#ifndef CHAIN_STACKH
#define CHAIN_STACKH
#include <iostream>
#include "stack.h"
#include "node.h"

template <class T>
class chainStack : public Stack<T>{
private:
	Node<T>* first;
	Node<T>* last;
	int stackTop;
public:
	chainStack() = delete;
	chainStack(Node<T>* f = nullptr);
	chainStack(const chainStack<T>& x);
	virtual bool empty() const;
	virtual int size() const;
	virtual T& top();
	virtual void pop();
	virtual void push(const T& theElement);
	virtual void show() const;
	~chainStack();
};

template <class T>
inline chainStack<T>::chainStack(Node<T>* f) :first(f), stackTop(0), last(nullptr) {
		Node<T>* p = first;
		while (p) {
			++stackTop;
			p = p->next;
		}
}

template <typename T>
inline chainStack<T>::chainStack(const chainStack<T>& x)
{
	Node<T>* run = x.first;
	Node<T>* tnext = nullptr;
	Node<T>* tprev = nullptr;
	while (run) {
		Node<T>* tmp = new Node<T>(run->element, tprev, tnext);
		if(tprev) tprev->next = tmp;
		if (!tprev) first = tmp;
		tprev = tmp;
		run = run->next;
	}
	last = tprev;
}

template<class T>
inline bool chainStack<T>::empty() const
{
	return (stackTop == 0);
}

template<class T>
inline int chainStack<T>::size() const
{
	return stackTop;
}

template<class T>
inline T& chainStack<T>::top()
{
	return last->element;
}

template<class T>
inline void chainStack<T>::pop()
{
	if (stackTop == 0)
		throw std::invalid_argument("Pop Error: No Element in Stack");
	if (last) {
		Node<T>* tmp = last;
		last = last->prev;
		if (last) {
			last->next = nullptr;
		}
		else {
			first = nullptr;
		}
		delete tmp;
		stackTop--;
	}
}


template<class T>
inline void chainStack<T>::push(const T& theElement) {
	Node<T>* tmp = new Node<T>(theElement, last, nullptr);
	if (last) last->next = tmp;
	else first = tmp;
	last = tmp;
	stackTop++;
}


template<class T>
inline void chainStack<T>::show() const {
	Node<T>* p = first;
	while (p) {
		std::cout << p->element << " ";
		p = p->next;
	}
	std::cout << std::endl;
}

template<class T>
inline chainStack<T>::~chainStack()
{
	Node<T>* p = first;
	Node<T>* that;
	while (p) {
		that = p;
		p = that->next;
		delete that;
	}
	first = nullptr;
	last = nullptr;
	stackTop = 0;
}




#endif // !CHAIN_STACKH