import java.util.Iterator;
import java.util.NoSuchElementException;

public class SLL<E> {
    private SLLNode<E> first;

    public SLL() {
        // Construct an empty SLL
        this.first = null;
    }

    public void deleteList() {
        first = null;
    }

    public int length() {
        int ret;
        if (first != null) {
            SLLNode<E> tmp = first;
            ret = 1;
            while (tmp.succ != null) {
                tmp = tmp.succ;
                ret++;
            }
            return ret;
        } else
            return 0;

    }

    @Override
    public String toString() {
        String ret = new String();
        if (first != null) {
            SLLNode<E> tmp = first;
            ret += tmp + "->";
            while (tmp.succ != null) {
                tmp = tmp.succ;
                ret += tmp + "->";
            }
        } else
            ret = "Prazna lista!!!";
        return ret;
    }

    public void insertFirst(E o) {
        SLLNode<E> ins = new SLLNode<E>(o, first);
        first = ins;
    }

    public void insertAfter(E o, SLLNode<E> node) {
        if (node != null) {
            SLLNode<E> ins = new SLLNode<E>(o, node.succ);
            node.succ = ins;
        } else {
            System.out.println("Dadenot jazol e null");
        }
    }

    public void insertBefore(E o, SLLNode<E> before) {

        if (first != null) {
            SLLNode<E> tmp = first;
            if(first==before){
                this.insertFirst(o);
                return;
            }
            //ako first!=before
            while (tmp.succ != before)
                tmp = tmp.succ;
            if (tmp.succ == before) {
                SLLNode<E> ins = new SLLNode<E>(o, before);
                tmp.succ = ins;
            } else {
                System.out.println("Elementot ne postoi vo listata");
            }
        } else {
            System.out.println("Listata e prazna");
        }
    }

    public void insertLast(E o) {
        if (first != null) {
            SLLNode<E> tmp = first;
            while (tmp.succ != null)
                tmp = tmp.succ;
            SLLNode<E> ins = new SLLNode<E>(o, null);
            tmp.succ = ins;
        } else {
            insertFirst(o);
        }
    }

    public E deleteFirst() {
        if (first != null) {
            SLLNode<E> tmp = first;
            first = first.succ;
            return tmp.element;
        } else {
            System.out.println("Listata e prazna");
            return null;
        }
    }

    public E delete(SLLNode<E> node) {
        if (first != null) {
            SLLNode<E> tmp = first;
            if(first ==node){
                return this.deleteFirst();
            }
            while (tmp.succ != node && tmp.succ.succ != null)
                tmp = tmp.succ;
            if (tmp.succ == node) {
                tmp.succ = tmp.succ.succ;
                return node.element;
            } else {
                System.out.println("Elementot ne postoi vo listata");
                return null;
            }
        } else {
            System.out.println("Listata e prazna");
            return null;
        }

    }

    public SLLNode<E> getFirst() {
        return first;
    }

    public SLLNode<E> find(E o) {
        if (first != null) {
            SLLNode<E> tmp = first;
            while (tmp.element != o && tmp.succ != null)
                tmp = tmp.succ;
            if (tmp.element == o) {
                return tmp;
            } else {
                System.out.println("Elementot ne postoi vo listata");
            }
        } else {
            System.out.println("Listata e prazna");
        }
        return first;
    }

    public Iterator<E> iterator () {
    // Return an iterator that visits all elements of this list, in left-to-right order.
        return new LRIterator<E>();
    }

    // //////////Inner class ////////////

    private class LRIterator<E> implements Iterator<E> {

        private SLLNode<E> place, curr;

        private LRIterator() {
            place = (SLLNode<E>) first;
            curr = null;
        }

        public boolean hasNext() {
            return (place != null);
        }

        public E next() {
            if (place == null)
                throw new NoSuchElementException();
            E nextElem = place.element;
            curr = place;
            place = place.succ;
            return nextElem;
        }

        public void remove() {
            //Not implemented
        }
    }

    public void mirror(){
        if (first != null) {
            //m=nextsucc, p=tmp,q=next
            SLLNode<E> tmp = first;
            SLLNode<E> newsucc = null;
            SLLNode<E> next;

            while(tmp != null){
                next = tmp.succ;
                tmp.succ = newsucc;
                newsucc = tmp;
                tmp = next;
            }
            first = newsucc;
        }

    }

    public void merge (SLL<E> in){
        if (first != null) {
            SLLNode<E> tmp = first;
            while(tmp.succ != null)
                tmp = tmp.succ;
            tmp.succ = in.getFirst();
        }
        else{
            first = in.getFirst();
        }
    }
}
class SLLTester {

    public static void main(String[] args) {
        SLL<Integer> lista = new SLL<Integer>();
        lista.insertLast(5);
        System.out.print("Listata po vmetnuvanje na 5 kako posleden element: ");
        System.out.println(lista.toString());

        lista.insertFirst(3);
        System.out.print("Listata po vmetnuvanje na 3 kako prv element: ");
        System.out.println(lista.toString());

        lista.insertLast(1);
        System.out.print("Listata po vmetnuvanje na 1 kako posleden element: ");
        System.out.println(lista.toString());

        lista.deleteFirst();
        System.out.print("Listata po brishenje na prviot element: ");
        System.out.println(lista.toString());

        SLLNode<Integer> pom = lista.find(5);
        lista.insertBefore(2, pom);
        System.out.print("Listata po vmetnuvanje na elementot 2 pred elementot 5: ");
        System.out.println(lista.toString());

        pom = lista.find(1);
        lista.insertAfter(3, pom);
        System.out.print("Listata po vmetnuvanje na elementot 3 posle elementot 1: ");
        System.out.println(lista.toString());

        Iterator<Integer> i = lista.iterator();
        System.out.print("Izminuvanje so iterator: ");
        while(i.hasNext())
            System.out.print(i.next()+" ");
        System.out.println();
        System.out.println("Momentalna dolzina na listata: "+lista.length());

        System.out.print("Listata po prevrtuvanje: ");
        lista.mirror();
        System.out.println(lista.toString());

        pom = lista.find(2);
        lista.delete(pom);
        System.out.print("Listata po brishenje na elementot 2: ");
        System.out.println(lista.toString());

        System.out.println("Momentalna dolzina na listata: "+lista.length());

        lista.deleteList();
        System.out.print("Pecatenje na listata po nejzino brishenje: ");
        System.out.println(lista.toString());
        System.out.println("Momentalna dolzina na listata: "+lista.length());

    }

}