/*
	Chapter 6:	Java Calculator
	Programmer:	Johnny Peralta
	Date:		4/24/2018
	Filename:	Calculator.java
	Purpose:	This program creates a calculator with a menu.
*/

import java.awt.*;
import java.awt.event.*;
import java.awt.datatransfer.*;
import java.text.DecimalFormat;
import javax.swing.JOptionPane;

public class Calculator extends Frame implements ActionListener
{
	private Button keys[];
	private Panel keypad;
	private TextField lcd;
	private double op1;
	private boolean first;
	private boolean foundkey;
	private boolean clearText;
	private int lastOp;
	private DecimalFormat calcPattern;

	public Calculator()
	{
		//creates an instance of the menu
		MenuBar mnuBar = new MenuBar();
		setMenuBar(mnuBar);

		//construct and pupulate the File menu
		Menu mnuFile = new Menu("File", true);
		menuBar.add(mnuFile);
			MenuItem mnuFileExit = new MenuItem("Exit");
			mnuFile.add(mnuFileExit);

		//construct and populate the Edit menu
		Menu mnuEdit = new Menu("Edit", true);
		mnu.Bar.add(mnuEdit);
			MenuItem mnuuEditClear = new MenuItem("Clear");
			mnuEdit.add(mnuEditClear);
			mnuEdit.insertSeperator(1);
			MenuItem mnuEditCopy = new MenuItem("Copy");
			menuEdit.add(mnuEditCopy);
			MenuItem mnuEditPast = new MenuItem("Paste");
			menuEdit.add(mnuEditPaste);

		//construct and populate the About menu
		Menu mnuAbout = new Menu("About", true);
			mnuBar.add(mnuAbout);
			MenuItem mnuAboutCalculator = new MenuItem("About Calculator");
			mnuAbout.add(mnuAboutCalculator);

		//add the ActionListener to each menu item
		mnuFileExit.addActionListener(this);
		mnuEditClear.addActionListener(this);
		mnuEditCopy.addActionListener(this);
		mnuEditPaste.addActionListener(this);
		mnuAboutCalculator.addActionListener(this);

		//assign an ActionCommand to each menu item
		mnuFileExit.setActionCommand(this);
		mnuEditClear.setActionCommand(this);
		mnuEditCopy.setActionCommand(this);
		mnuEditPaste.setActionCommand(this);
		mnuAboutCalculator.setActionCommand(this);

		//construct components and initialize beginning values
		lcd = new TextField(20);
			lcd.setEditable(false);
		keypad = new panel();
		keys = new Button(16);
		first = true;
		op1 = 0.0;
		clearText = true;
		lastOp = 0;
		calcPattern = new DecimalFormat("########.########");

		//construct and assign captions to the Buttons
		for (int i=0; i<=9; i++)
			keys[i] = new Button(String.valueOf(i));

		keys[10] = new Button("/");
		keys[11] = new Button("*");
		keys[12] = new Button("-");
		keys[13] = new Button("+");
		keys[14] = new Button("=");
		keys[15] = new Button(".");

		//set frame and keypad layout to grid layout
		setLayout(new BorderLayout());
		keypad.setLayout(new GridLayout(4,4,10,10));

			for (int i=7; i<=10; i++) //7, 8 , 9, divide
				keypad.add(keys[i]);

			for (int i=4; i<=16; i++) //4, 5 , 6, divide
				keypad.add(keys[i]);

			keypad.add(keys[11]); //multiply

			for (int i=1; i<=3; i++) //1, 2 , 3
				keypad.add(keys[i]);

				keypad.add(keys[12]); //subtract

				keypad.add(keys[0]); //0 key

			for (int i=15; i>=13; i--)
				keypad.add(keys[i]); // decimal point, =, add(+) keys

			for (int i=0; i<keys.length; i++)
				keys[i].addActionListener(this);

			add(lcd, BorderLayout.NORTH);
			add(keypad, BorderLayout.CENTER);

			addWindowListener(
				new WindowAdapter()
					{
					public void windowClosing(WindowEvent e )
						{
							System.exit(0);
						}
					}
		);

	} // end of constructor method

	public void actionPerformed(ActionEvent e)
	{
		// test for menu item clicks
		String arg = e.getActionCommand();
		if (arg == "Exit")
			System.exit(0);

		if (arg == "Clear")
		{
			clearText = true;
			first = true;
			op1 = 0.0;
			lcd.setText("");
			lcd.requestFocus();
		}

		if (arg == "Copy")
		{
			Clipboard cb = Toolkit.getDefaultToolkit().getSystemClipboard();
			StringSelection contents = new StringsSelection(lcd.getText());
			cb.setContents(contents, null);
		}

		if (arg == "Paste")
		{
			Clipboard cb = Toolkit.getDefaultToolkit().getSystemClipboard();
			Transferable content = cb.getContents(this);
			try
			{
				String s = (String)content.getTransferData(DataFlavor.stringFlavor);
				lcd.setText(calcPattern.format(Double.parseDouble(s)));
			}
			catch (Throwable exc)
			{
				lcd.setText("");
			}
		}

		if (arg == "About")
		{
			String message = "Calculator ver. 1.0\nOpenExhibit Software\nCopyright 2007\nAll rights reserved";
			JOptionPane.showMessageDialog(null, message,"About Calculator", JOptionPane.INFORMATION_MESSAGE);
		}

		//test for button clicks
		foundKey = false;

		//search for the clicked key
		for (int i=0; i<keys.length && !foundKey; i++)
		{
			if(e.getSource() == keys[i])
				foundKey = true;
				switch(i)
				{
					//number and decimal point buttons
					case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8: case 9: case 15:
						if(clearText)
						{
							lcd.setTexT("");
							clearText = false;
						}
						lcd.setText(lcd.getText() + keys[i].getLabel());
						break;

						// operator buttons
						case 10: case 11: case 12: case 13: case 14:

						clearText = true;

						if (first) // first operand
						{
							if(lcd.getText().length()==0) op1 = 0.0;
							else op1 = Double.parseDouble(lcd.getText());

							first = false;
							clearText = true;
							lastOp = i; // save last operator
						}

						else // second operand
						{
							switch(lastOp)
							{
								case 10: // divide button
									opl /= Double.parseDouble(lcd.getText());
									break;
								case 11: // multiply button
									op1 *= Double.parseDouble(lcd.getText());
									break;
								case 12: // minuse button
									op1 -= Double.parseDouble(lcd.getText());
									break;
								case 13: // plus button
									op1 += Double.parseDouble(lcd.getText());
									break;
								} // end of switch(lastOp)
								lcd.setText(calcPattern.format(op1));
								clearText = True;

								if(i==14) first = true; // equal button
								else lastOp = i; // save last operator
							}
							break;
						} // end of switch(i)
					} // end of if
				} // end of for
			} // end of action preformed

	public static void main(String args[])
	{
	// set frame properties
	Calculator f = new Calculator();
	f.setTitle("Calculator Application");
	f.setBounds(200,200,300,300);
	f.setVisible(true);

	// set image properties and add to frame
	Image icon = Toolkit.getDefaultToolkit().getImage("calcImage.gif");
	f.setIconImage(icon);

	} // end of main
} // end of class