package org.kne.cloud.network.congestion;

import java.util.Iterator;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReferenceArray;

public class SendByteSlidingWindow<E> implements Iterable<E>{
	private Object[] array;
	private volatile int windowSize ;
	private volatile long windowPosition;
	
	public int getWindowSize() {
		return windowSize;
	}

	public void setWindowSize(int windowSize) {
		this.windowSize=windowSize;
	}
	
	public long getWindowPosition() {
		return windowPosition;
	}

	public void setWindowPosition(long windowPosition) {
		this.windowPosition=windowPosition;
	}

	public SendByteSlidingWindow(int capacity,int windowSize){
		if(windowSize>capacity) {
			throw new IllegalArgumentException("windowSize>capacity!");
		}
		array= new Object[capacity];
		this.windowSize=windowSize;
	}
	
	public boolean checkPush() {
		if(array[calcPosition(windowPosition-windowSize)]==null ) {
			return true;
		}
		return false;
	}
	
	public void push(E object) {

		array[calcPosition(windowPosition)]= object;
	}

	public E remove(long number) {
		if(number<windowPosition&&number>=windowPosition-windowSize) {
			int indp=calcPosition(number);
			E old=(E) array[indp];
			array[indp]=null;
		return old;
		}else {
			return null;
		}
	}

	public boolean isEmpty() {
		for (long i = windowPosition-windowSize; i < windowPosition; i++) {
			if(array[calcPosition(i)]!=null) {
				return false;
			}
		}
		return true;
	}

	public E get(long number) {
		if(number<windowPosition&&number>=windowPosition-windowSize) {
			return (E) array[calcPosition(number)];
			}else {
				return null;
			}
	}

	@Override
	public Iterator<E> iterator() {
		return new Iterator<E>() {
			private long pointer=windowPosition-windowSize;
			@Override
			public boolean hasNext() {
				return pointer<windowPosition;
			}

			@Override
			public E next() {
				return (E) array[calcPosition(pointer++)];
			}
		};
	}
	private int calcPosition(long number) {
		return (int) ((number+array.length)%array.length);
	}
}