package cz.cvut.fel.pjv;

/**
 * Implementation of the {@link Queue} backed by fixed size array.
 */
public class CircularArrayQueue implements Queue {
    private int size;
    private String[] buffer;
    private int lastUse;
    /**
     * Creates the queue with capacity set to the value of 5.
     */
    public CircularArrayQueue() {
        size = 0;
        buffer = new String[5];
        lastUse = 0;
    }


    /**
     * Creates the queue with given {@code capacity}. The capacity represents maximal number of elements that the
     * queue is able to store.
     * @param capacity of the queue
     */
    public CircularArrayQueue(int capacity) {
        size = 0;
        buffer = new String[capacity];
    }

    public int size() {
        return lastUse;
    }


    public boolean isEmpty() {
        if (lastUse == 0){
            return true;
        }
        return false;
    }


    public boolean isFull() {
        return lastUse == buffer.length;
    }


    public boolean enqueue(String obj) {
        if (!isFull() && obj != ""){
            buffer[lastUse] = obj;
            lastUse++;
        }
        return false;
    }


    public String dequeue() {
        if (!isEmpty()){
            String head = buffer[0];
            for (int i =0; i < buffer.length-1;i++){
                buffer[i] = buffer[i+1];
            }
            lastUse--;
            return head;
        }
        return null;
    }


    public void printAllElements() {
        for (int i = 0; i< buffer.length; i++){
            if (buffer[i] != null){
                System.out.println(buffer[i]);
            }
            else {
                break;
            }
        }
    }
}