import java.io.*;
import java.text.*;
import java.awt.event.*;
import java.awt.*;

// Main class that instantiates the frame.
public class OrderFrame
{
     public static void main (String [] args)
     {
          OrderWindow frame = new OrderWindow ();
          frame.addWindowListener (new WindowCloser ());
          frame.show ();
     } // main method
} // class ShowFrames

// class to activate the closing icon on the frame.
class WindowCloser extends WindowAdapter
{
     public void windowClosing (WindowEvent e){System.exit (0);}
} // class WindowCloser

// class that creates a frame with a panel, text area, and three buttons.  It also instantiates the list.
class OrderWindow extends Frame
{
     private Panel panel;
     private Label areaLabel;
     private TextArea area;
     private OrderList list;
     private Button readFile, display, save;
 
     OrderWindow ()
     {
          super ("Orders");
          setSize (300, 300);
          panel = new Panel ();
          panel.setBackground (Color.cyan);
          areaLabel = new Label ("Order");
          area = new TextArea (10, 30);
          panel.add (areaLabel); panel.add (area);

          readFile = new Button ("Read Order");
          readFile.addActionListener (new ReadListener ());
          panel.add (readFile);

          display = new Button ("Display Order");
          display.addActionListener (new DisplayListener ());
          panel.add (display);
 
          save = new Button ("Save Order");
          save.addActionListener (new SaveListener ());
          panel.add (save);
          add (panel);
 
          list = new OrderList ();
     } // constructor

     // Inner class that listens to the display button.
    class DisplayListener implements ActionListener
     {
          public void actionPerformed (ActionEvent e) {list.displayOrders (area);}
     } // class DisplayListener

     // Inner class that listens to the read button.
     class ReadListener implements ActionListener
     {
          public void actionPerformed (ActionEvent e) {list.readOrders ();}
     } // class ReadListener

     // Inner class that listens to the save button.
     class SaveListener implements ActionListener
     {
          public void actionPerformed (ActionEvent e) {list.saveOrders ();}
     } // class SaveListener
} // class OrderFrame

/* class that creates an manages a linked list of orders.  Orders are added to the end of the list.  The list can be displayed in a text area and saved to a second file. */
class OrderList
{
     private Order listHead, listRear;
     final int maxSize = 10;
     private int listSize;
 
     OrderList ()
     {
          listHead = null;
          listRear = null;
     } // constructor
 
     // Method that reads orders from a text file and adds them to the end of a linked list.
     public void readOrders ()
     {
          String title;
          try
          {
               BufferedReader orderFile = new BufferedReader (new InputStreamReader (new FileInputStream ("orderFile.txt")));
               title = orderFile.readLine ();
               while ((title != null) && (listSize < maxSize))
               {
                    Order order = new Order (title);
                    order.readOrder (orderFile);
                    addToEnd (order);
                    title = orderFile.readLine ();
               }
               orderFile.close ();
          }catch (IOException e) {System.out.println ("File Error");}
     } // method readOrders

     // private method to add orders to the end of a list.
     private void addToEnd (Order newOrder)
     {
          if (listHead == null)
          {
               listHead = newOrder;
               listRear = newOrder;
          }
          else
          {
               listRear.setNext (newOrder);
               listRear = newOrder;
          }
     } // method addToEnd
 
     // Method that displays the list of orders in a text area and then displays the total cost.
     public void displayOrders (TextArea area)
     {
          Order tempOrder = listHead;
          while (tempOrder != null)
          {
               tempOrder.displayOrder (area);
               tempOrder = tempOrder.getNext ();
          }
          area.append ("The total cost is " + NumberFormat.getCurrencyInstance ().format (calculateTotal ()) + '\n');
     } // method displayOrders

     // private method that calculates the total cost.
     private double calculateTotal ()
     {
          double total = 0;
          Order tempOrder = listHead;
          while (tempOrder != null)
          {
               double price = tempOrder.getPrice ();
               int quantity = tempOrder.getQuantity ();
               total += price * quantity;
               tempOrder = tempOrder.getNext ();
          }
          return total;
     } // method totalCost
 
     // Method that saves the list of orders, followed by the total cost, to a second file.
     public void saveOrders ()
     {
          try
          {
               PrintStream outfile = new PrintStream (new FileOutputStream ("orderFile2.txt"));
               Order tempOrder = listHead;
               while (tempOrder != null)
               {
                    tempOrder.outputOrder (outfile);
                    tempOrder = tempOrder.getNext ();
               }
               outfile.println ("The total cost is " + NumberFormat.getCurrencyInstance ().format (calculateTotal ()));
               outfile.close ();
          } catch (FileNotFoundException e) {System.out.println ("No File");}
     } // method saveOrders
} // class OrderList

// class that defines an order with a next field for attaching an instance to the end of the list.
class Order
{
     private String name, id;
     private double price;
     private int quantity;
     private Order next;
 
     Order (String name)
     {
          this.name = name;
          next = null;
     } // constructor
 
     protected Order getNext () { return next;}
     protected void setNext (Order newOrder) { next = newOrder;}
 
     public double getPrice () {return price;}
     public int getQuantity () { return quantity;}

     // Method to read a single order from the file.
     public void readOrder (BufferedReader orderFile) throws IOException
     {
          id = orderFile.readLine ();
          price = Double.parseDouble (orderFile.readLine ());
          quantity = Integer.parseInt (orderFile.readLine ());
     } // method readOrder
 
     // Method to display an order in the text area.
     public void displayOrder (TextArea area)
     {
          area.append ("Product Name: " + name + '\n');
          area.append ("Product ID: " + id + '\n');
          area.append ("Price: " + price + '\n');
          area.append ("Quantity: " + quantity + '\n' + '\n');
     } // method displayOrder
 
     // Method to print the order to an output file.
     public void outputOrder (PrintStream outfile)
     {
          outfile.println ("Product Name: " + name);
          outfile.println ("Product ID: " + id);
          outfile.println ("Price: " + price);
          outfile.println ("Quantity: " + quantity);
          outfile.println ();
     } // method outputOrder
} // class Order