package com.company;

import java.util.Objects;

public class Anchor {
    private Element first = null;

    public Anchor() { }

    public void insertAtTheFront(final int x) {
        final Element newElement = new Element(x);
        if(first != null)
            newElement.setNextElement(first);

        first = newElement;
    }

    public void insertAtTheEnd(final int x) {
        final Element newElement = new Element(x);
        if(first == null) {
            first = newElement;
        }
        else {
            Element element = first;
            //set 'element' to last element in list
            while(element.getNextElement() != null)
                element = element.getNextElement();

            element.setNextElement(newElement);
        }
    }

    public void removeFirst() {
        if(first != null){
            first = first.getNextElement();
        }
    }

    public void removeLast() {
        if(first != null) {

            Element preLastElement = first;
            //Set 'preLastElement' to point to 1 element before last one
            for(Element element = first; element.getNextElement() != null; element = element.getNextElement()){
                if(element.getNextElement().getNextElement() == null){
                    preLastElement = element;
                    break;
                }
            }

            preLastElement.setNextElement(null);
        }
    }

    @Override
    public String toString() {
        String str = "List [";

        if(first != null) {
            Element element = first;
            do {
                str += element.getValue() + " ";

                element = element.getNextElement();
            } while (element != null);
        }

        return str + "]";
    }

    @Override
    public boolean equals(Object o) {
        if (o == null || getClass() != o.getClass())
            return false;

        final Anchor otherAnchor = (Anchor) o;
        Element otherAnchorElement = otherAnchor.first;
        Element thisElement = first;
        do {
            if(thisElement == null || otherAnchorElement == null)
                return thisElement == otherAnchorElement;

            if(thisElement.getValue() != otherAnchorElement.getValue())
                return false;

            thisElement = thisElement.getNextElement();
            otherAnchorElement = otherAnchorElement.getNextElement();
        } while(otherAnchorElement != null && thisElement != null);

        return true;
    }
}