import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.text.*;

/**
 * Class representing an order tracking UI.  Responsible
 * for displaying the state of the order queue at all times.
 */
public class TrackingDisplayUI extends JFrame implements Observer {
    private JTextArea _textArea;  // Multiline area for order display

    /** Constructor */
    public TrackingDisplayUI() {
        super("APDTS - Order Tracking");

        _textArea = new JTextArea(10,40);
        _textArea.setEditable(false);

        JScrollPane areaScrollPane = new JScrollPane(_textArea);
        areaScrollPane.setVerticalScrollBarPolicy(
        		JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);

        this.getContentPane().add(areaScrollPane);
        this.pack();
    }

    /**
     * Makes the UI display the data from the given
     * queue.
     * @param queue Queue to load data from (non-null)
     */
    public void display(OrderQueue queue) {
        _textArea.setText("");

        /* Suggested interface: 
        Iterator i = queue.iterator();
        while (i.hasNext()) {
            Order ord = (Order)i.next();
            _textArea.append(displayableString(ord));
        }
        */
    }

    // Formatter object to use to write just the hour and minute
    // information from a Date object into a String:
    private final SimpleDateFormat formatter = new SimpleDateFormat("hh:mm a");

    // Retrieve a displayable (possibly multiline) string from
    // an Order object
    private String displayableString(Order ord) {
        // Example: 5:12 12" OPR 1245 Oak St.
        StringBuffer buf = new StringBuffer();
        /* Suggested interface: 
        Iterator i = ord.pizzaIterator();
        while (i.hasNext()) {
            buf.append(formatter.format(ord.getEnqueueTime()));
            buf.append("\t");
            Pizza p = (Pizza)i.next();
            buf.append(p.getSize());
            buf.append("\t");
            buf.append(p.getToppings());
            buf.append("\t");
            buf.append(ord.getCustomerAddress());
            buf.append("\n");
        }
        */
        return buf.toString();
    }

    /**
     * Updates display when interesting events happen.
     * @param subject Must be an OrderQueue
     * @param data unused
     */
    public void update(Observable subject, Object data) {
        this.show(); // Just in case it was hidden.
        this.display((OrderQueue)subject);
    }

    // Unit test.
    public static void main(String[] args) {
        new TrackingDisplayUI().show();
    }
};