/*	Submitted by:	Maderal, Kurt Merkell John P.
//					ICS 20 A
//					Xavier University
//
//
//
//	An implementation of an Array-Based Queues
*/


import java.io.*;

public class  QueueArray
{
	private BufferedReader SizeReader;
	private BufferedReader ItemReader;
	private Object storage[];
	private int front,rear,check;
	private String inp3;
	private int N;

	// constructor named Queues to instantiate the size of the array "storage" and other variables
	public QueueArray() throws IOException
	{
		try
		{
			System.out.println("\n   -------------------- Array-Based Queue --------------------\n");
			SizeReader = new BufferedReader(new InputStreamReader(System.in));
			System.out.print("Input the Size :  Array of Objects:  ");
			N = Integer.parseInt(SizeReader.readLine()) + 1;

			storage = new Object [ N ];
			front = 0;
			rear = 0;
			check = 0; //-1 if reset
			instruct();
			access();
		}
		catch (Exception e)
		{
			System.out.println("\n                      ERROR.... Pls. TRY AGAIN...\n");
			reset();
		}
	}

	// method instructions
	public void instruct()
	{
		System.out.println("\nCommands for Methods: type  \" e \" for "+"\"Enqueue\""+"     with your Input...");
		System.out.println("                            \" d \" for "+"\"Dequeue\"");
		System.out.println("                            \" f \" for "+"\"Front\"");
		System.out.println("                            \" s \" for "+"\"Size\"");
		System.out.println("                            \" y \" for "+"\"IsEmpty?\"");
		System.out.println("                            \" r \" for "+"\"Reset All\"");
        System.out.println("                            \" p \" for "+"\"Print / Display All Inputs\"");
		System.out.println("                            \" i \" for "+"\"Commands / Instructions / HELP\"");
		System.out.println("                            \" x \" for "+"\"Exit Program\"\n\n");
		System.out.println("                    --------> NOTE  :     NO SPACES.... <--------\n\n");

	}

	//method access() for starting
	public void access() throws IOException
	{
		// "infinite for loop" so that inputs are ask over and over
		// if check == -1 then loop terminates and reset method is called
		for (; ; )
		{
			inputs();
			if (check==-1)
			{
				break;
			}
		}
		reset();
	}

	//reset method that calls for a new Object of type Queues
	public void reset() throws IOException
	{
		QueueArray q = new QueueArray();
	}

	//method inputs()
	public void inputs() throws IOException
	{
		ItemReader = new BufferedReader(new InputStreamReader(System.in));
		System.out.print("Type Command:  ");
		inp3 = ItemReader.readLine();
		String com3 = (inp3.charAt(0)+"");


			if ( (com3.equals("e"))||(com3.equals("d"))||(com3.equals("f"))||(com3.equals("s"))||(com3.equals("y"))||(com3.equals("x"))||(com3.equals("r"))||(com3.equals("p"))||(com3.equals("i")) )
			{
				if (com3.equals("e"))
				{
					String s3 = "";
					for (int i=1; i<inp3.length(); i++)
					{
						s3 += (inp3.charAt(i)+"");
					}
						enqueue(new String(s3));
				}
				if (com3.equals("d"))
				{
					dequeue();
				}
				if (com3.equals("s"))
				{
					System.out.println("                      Size     :     "+ size());
				}
				if (com3.equals("f"))
				{
					System.out.println("                      Front    :     "+ front());
				}
				if (com3.equals("y"))
				{
					System.out.println("                      IsEmpty? :     "+ IsEmpty());
				}
				if (com3.equals("x"))
				{
					System.out.println("\n\n                      Program Terminated...");
					System.exit(0);
				}
				if (com3.equals("p"))
				{
                    displayInputs();
				}
				if (com3.equals("i"))
				{
					instruct();
				}
				if (com3.equals("r"))
				{
					check = -1;
				}
			}
			else
				{
					System.out.print("                      Command Not Found!...\n");
				}
	}//end of method -->  inputs ( )


	// method size : returns the size of inputs that have been added
	public int size()
	{
		return ( N - front + rear ) % N ;
	}

	// method IsEmpty : returns " true " if queue is Empty, " false " otherwise
	public boolean IsEmpty()
	{
		return front == rear;
	}

	// method enqueue : adding of inputs to the queue
	public void enqueue(Object item)
	{
		if (size()==N-1)
		{
			System.out.println("                      Error..!!! Queue is Full...");
		}
		else
			{
				storage[rear] = item;
				rear = (rear+1) % N;
				System.out.println("                      Enqueued :     "+ item);
			}

	}

	// method dequeue : removing the first element input in the queue
	public void dequeue()
	{
		if (IsEmpty())
		{
			System.out.println("                      Error..!!! Queue is Empty...");
		}
		else
			{
				Object temp = storage[front];
				System.out.println("                      Dequeued :     "+ temp);
				storage[front] = null;
				front = (front + 1 ) % N;
			}
	}

	// method front : return and show the item / element that will be dequeued next
	public Object front()
	{
		if ( IsEmpty() )
		{
			return (new String("Error..!!! Queue is Empty..."));
		}
		else return storage[front];
	}

	// method dispayInputs : this method reveals all the items or elements stored in the array
	public void displayInputs()
	{
		String dis="";
		if (! IsEmpty() )
		{
    		for (int i=0; i<N; i++)
    		{
    			if (storage[i] != null)
    			{
    				dis += (storage[i] + ", ");
    			}
    		}
    		System.out.println("\nALL Stored inputs  :-->>    "+dis+"\n");
    	}
        else System.out.println("                      Error..!!! Queue is Empty..."); 
	}

	//main application
	public static void main(String args[]) throws IOException
	{
		QueueArray q = new QueueArray();
	}
}