package Question4;
import java.util.Iterator;
public class Stack<Item> implements Iterable<Item> {

    private int N;
    private Node first;

    private class Node {
        //This is the primitive implementation of a linked list in Java.
        //defined a class named node with an "item" and a Node object "next".
        Item item;
        Node next;
    }
    public Item pop() {
        Item item = first.item;
        first = first.next;
        N--;
        return item;
    }

    public Stack() {
        N = 0;
        first = null;
    }

    public void add(Item item) {
        Node oldfirst = first;
        first = new Node();
        first.item = item;
        first.next = oldfirst;
    }

    public void push(Item item) {
        Node temp = new Node();

        if (temp == null) {
            System.out.print("\nHeap Overflow");
            return;
        }

        temp.item = item;
        temp.next = first;
        first = temp;
    }
    public Item peek()
    {
        // check for empty stack
        if (!isEmpty()) {
            return first.item;
        }
        else {
            System.out.println("Stack is empty");
            return null;
        }
    }


    public boolean isEmpty() {
        return !iterator().hasNext(); //returns true if node reference is null
    }

    public int size() {
        return N;
    }

    public Iterator<Item> iterator() {
        return new ListIterator();
    }


    private class ListIterator implements Iterator<Item> {
        private Node current = first;

        public boolean hasNext() {
            // TODO Auto-generated method stub
            return current != null;
        }

        public Item next() {
            // TODO Auto-generated method stub
            Item item = current.item;
            current = current.next;
            return item;
        }

        public void remove() {
        }

    }

    public Stack<String> copy(Stack<String> stackClient) {
        Stack<String> resultStack = new Stack<String>();
        Stack<String> tempStack = new Stack<String>();
        Iterator<String> iterator = stackClient.iterator();
        while (iterator.hasNext()) {
            tempStack.add(iterator.next());
        }

        Iterator<String> tempIterator = tempStack.iterator();
        while (tempIterator.hasNext()) {
            resultStack.add(tempIterator.next());
        }

        return resultStack;
    }

    public Stack<String> inverse(Stack<String> stackClient) {
        Stack<String> resultStack = new Stack<String>();
        for (String s : stackClient){
            String a = stackClient.pop();
            resultStack.push(a);
        }

        return resultStack;
    }


    public static void main(String[] args) {
        Stack<String> stack = new Stack<String>();


        stack.add("Parsa");
        stack.add("pooria");
        stack.add("Paniz");
        stack.add("Anis");
        stack.add("Ritesh");

        for(String s : stack){
            System.out.println(s);
        }

        System.out.println("--------------------");


        Stack<String> invertedStack = stack.inverse(stack);

        for(String s: invertedStack){
            System.out.println(s);
        }

        System.out.println("--------------------");

        Stack<String> copiedStack = stack.copy(stack);

        for(String s : copiedStack){
            System.out.println(s);
        }




    }
}