package edu.gmu;

/** This class creates a circular queue backed by an array and then tests it. */
public class TestGmu {
    
    private int count = 0;
    
    private int back=0;
    private int front=0;
    
    /** How big can our queue be? */
    public static final int MAX_QUEUE = 5;
    
    /** This is the actual array we're using to hold the data. */
    private char [] arr = new char[MAX_QUEUE];
    
    /** Are we in debug mode or not? 1=ON, 2=OFF.*/
    private static final int DEBUG = 1;
    
    /** Constructor. For now, doesn't need to do anything. */
    public TestGmu() {
    }
    
    /** Remove everything from the queue. */
    public void clearQueue() {
    }
    
    /** Returns true if the queue is empty. */
    public boolean isEmpty() {
        if (count == 0)
            return true;
        else
            return false;
        
        // Works... and is a little nicer!
        //return (count == 0);
        
        // Why doesn't this work?
        //if (arr[front] == null) return true;
        //else return false;
    }
    
    /** Returns true if the queue is full. */
    public boolean isFull() {
        
        return (count == MAX_QUEUE-1);
    }
    
    /** Add the characater c into the queue.
     *  @return true if the char is added to the queue, false otherwise.  */
    public boolean enqueue(char c) {
        
        if(isFull()) return false;
        
        arr[back] = c;
        back = (back+1) % MAX_QUEUE;
        
        count++;
        
        return true;
    }
    
    /** Return the first element in the array. Throws EmptyQueueException if the queue
     *  is empty */
    public char dequeue() {
        if (isEmpty()) throw new RuntimeException("Empty Queue"); // DEBUG: NEED TO FIX AND THROW CORRECT EXCEPTION
        char temp = arr[front];
        arr[front] = ' ';
        front = (front+1) % MAX_QUEUE;
        count--;
        return temp;
    }
    
    /** Debug method to print the queue in order! */
    private void printQueue() {
        for (int i=0; i<MAX_QUEUE; i++) {
            System.out.print(i+":"+arr[i]);
        }
        System.out.println();
    }
    
    /** Print the queue in order from front to back */
    private void printQueueInOrder() {
        System.out.printf("Count: %d ", count);
        for (int i=0; i<count; i++) {
            System.out.print(arr[(front + i) % MAX_QUEUE]+" ");
        }
        System.out.println();
    }
    
    public static void main(String args[]) {
        TestGmu tst = new TestGmu();
        
        // Test code
        tst.enqueue('a');
        tst.printQueueInOrder();
        tst.enqueue('b');
        tst.printQueueInOrder();
        tst.enqueue('c');
        tst.printQueueInOrder();
       
        tst.enqueue('d');
        tst.printQueueInOrder();
        tst.enqueue('e');
        tst.printQueueInOrder();
        tst.enqueue('f');
        
        char c = tst.dequeue();
        System.out.println("Dequeue'd : "+c);
        tst.printQueueInOrder();
        
        c = tst.dequeue();
        System.out.println("Dequeue'd : "+c);
        tst.printQueueInOrder();
        
        System.out.println("Enqueue'd : "+'f');
        tst.enqueue('f');
        tst.printQueueInOrder();
    }
    
    
    
}