// PalindromeGui.java

import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.GridBagConstraints;
import java.awt.Component;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JTextArea;
import javax.swing.JButton;
import javax.swing.JPanel;

// constructor of program frame
public class PalindromeGuiFrame extends JFrame
{
	private GridBagLayout layout; // layout of frame
	private GridBagConstraints constraints; // constraints of layout
	private JPanel buttonJPanel;
	private JLabel promptLabel;
	private JTextField textField;
	private JTextArea textArea;
	private JButton checkJButton;
	private JButton exitJButton;
	private PalindromeChecker p;

	// set up GUI
	public PalindromeGuiFrame()
	{
		super( "PalindromeChecker" );
		layout = new GridBagLayout();
		setLayout( layout );
		constraints = new GridBagConstraints();

		p = new PalindromeChecker(); // create PalindromeChecker object

		// create GUI components
		promptLabel = new JLabel ( " Enter a string in the text field below. " );
		textField = new JTextField( 25 );
		textArea = new JTextArea( 5, 25 );
		checkJButton = new JButton( " Check " );
		exitJButton = new JButton( "Exit " );
		buttonJPanel= new JPanel();

		// add label
		constraints.fill = GridBagConstraints.HORIZONTAL;
		constraints.anchor = GridBagConstraints.WEST;
		addComponent( promptLabel, 0, 0, 1, 1 );

		// add text field
		addComponent( textField, 1, 0, 1, 1 );

		// add text Area
		constraints.fill = GridBagConstraints.BOTH;
		constraints.weightx = 1;
		constraints.weighty = 1;
		addComponent( textArea, 2, 0, 1, 1 );

		// add panel of buttons
		buttonJPanel.setLayout( new GridLayout( 1, 2 ) );
		buttonJPanel.add( checkJButton );
		buttonJPanel.add( exitJButton );
		constraints.weighty = 0;
		addComponent( buttonJPanel, 3, 0, 1, 1 );

		// register handlers
		checkButtonHandler checkHandler = new checkButtonHandler();
		checkJButton.addActionListener( checkHandler );
		exitButtonHandler exitHandler = new exitButtonHandler();
		exitJButton.addActionListener( exitHandler );
	} // end PalindromeGuiFrame


		// method to set constraints on
		private void addComponent( Component component, int row, int column,
			int width, int height )
		{
			constraints.gridx = column;
			constraints.gridy = row;
			constraints.gridwidth = width;
			constraints.gridheight = height;
			layout.setConstraints( component, constraints );
			add( component );
		} // end method addComponent


		// process text and test for palindrome
		private class checkButtonHandler implements ActionListener
		{
			// handle check Button event
			public void actionPerformed( ActionEvent event )
			{
				int length; // length of user-entered string
				int newlength; // length of processed string
				String str = "";
				String txt = textField.getText();
				String results = ""; // result message

				length = txt.length();
				textArea.setLineWrap( true );
				textArea.setWrapStyleWord( true );

				if ( length == 0 )
				{
					textArea.setText( "No valid string was entered. " +
						"The program ignores whitespace, punctuation marks, symbols and case. " +
						"Please enter at least one letter or number.");
				} // end if
				else
				{
					p.settestString( txt );
					str = p.parseString();
					newlength = str.length();
					if ( newlength == 0 )
					{
						textArea.setText( "The user-entered string, after processing, has no valid characters.  " +
						"The program ignores whitespace, punctuation marks, symbols and case.  " +
						"Please enter at least one letter or number." );
					}
					else
					{
						textArea.setLineWrap( false );
						textArea.setWrapStyleWord( false );
						if ( p.testPalindrome( p.parseString() ) )
						{
							results = String.format( "%s: %s\n%s: %s\n%s: %d\n%s: %d\n%s", "Original String",
								p.gettestString(), "Parsed String", p.parseString(),
								"Length of original string", length, "Length of parsed string",str.length(),
								"TRUE. String is a palindrome." );

							textArea.setText( results );
						}
						else
						{
							results = String.format( "%s: %s\n%s: %s\n%s: %d\n%s: %d\n%s", "Original String",
								p.gettestString(), "Parsed String", p.parseString(),
								"Length of original string", length, "Length of parsed string", str.length(),
								"FALSE. String is not a palindrome." );

							textArea.setText( results );
						} // end else
					}// end else
				} // end else
				textField.setText( "" ); // clear text field for another entry
			} // end method actionPerformed
		} // end inner class okButtonHandler


		// exit the program when button clicked
		private class exitButtonHandler implements ActionListener
		{
			// handle exit event
			public void actionPerformed( ActionEvent event )
			{
				System.exit( 0 );
			} // end method
		} // end inner class

} // end class