/*******************************************************************************
 * Copyright (c) 2001, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Jens Lukowski/Innoopract - initial renaming/restructuring
 *     
 *******************************************************************************/
package org.eclipse.wst.sse.ui.util;

import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.dialogs.IInputValidator;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;

/**
 * A simple input dialog for soliciting an input string from the user.
 * <p>
 * This concete dialog class can be instantiated as is, or further subclassed
 * as required.
 * 
 * NOTE: This class was mainly copied from
 * org.eclipse.jface.dialogs.InputDialog except the error message label was
 * turned into a read-only text widget to make the dialog accessible.
 * (https://bugs.eclipse.org/bugs/show_bug.cgi?id=61069)
 * </p>
 */
public class AccessibleInputDialog extends Dialog {

	/**
	 * Error message read-only text widget.
	 */
	private Text errorMessageLabel;

	/**
	 * The message to display, or <code>null</code> if none.
	 */
	private String message;

	/**
	 * Ok button widget.
	 */
	private Button okButton;

	/**
	 * Input text widget.
	 */
	private Text text;


	/**
	 * The title of the dialog.
	 */
	private String title;

	/**
	 * The input validator, or <code>null</code> if none.
	 */
	private IInputValidator validator;

	/**
	 * The input value; the empty string by default.
	 */
	private String value = "";//$NON-NLS-1$

	/**
	 * Creates an input dialog with OK and Cancel buttons. Note that the
	 * dialog will have no visual representation (no widgets) until it is told
	 * to open.
	 * <p>
	 * Note that the <code>open</code> method blocks for input dialogs.
	 * </p>
	 * 
	 * @param parentShell
	 *            the parent shell
	 * @param dialogTitle
	 *            the dialog title, or <code>null</code> if none
	 * @param dialogMessage
	 *            the dialog message, or <code>null</code> if none
	 * @param initialValue
	 *            the initial input value, or <code>null</code> if none
	 *            (equivalent to the empty string)
	 * @param validator
	 *            an input validator, or <code>null</code> if none
	 */
	public AccessibleInputDialog(Shell parentShell, String dialogTitle, String dialogMessage, String initialValue, IInputValidator validator) {
		super(parentShell);
		this.title = dialogTitle;
		message = dialogMessage;
		if (initialValue == null)
			value = "";//$NON-NLS-1$
		else
			value = initialValue;
		this.validator = validator;
	}

	/*
	 * (non-Javadoc) Method declared on Dialog.
	 */
	protected void buttonPressed(int buttonId) {
		if (buttonId == IDialogConstants.OK_ID) {
			value = text.getText();
		} else {
			value = null;
		}
		super.buttonPressed(buttonId);
	}

	/*
	 * (non-Javadoc) Method declared in Window.
	 */
	protected void configureShell(Shell shell) {
		super.configureShell(shell);
		if (title != null)
			shell.setText(title);
	}

	/*
	 * (non-Javadoc) Method declared on Dialog.
	 */
	protected void createButtonsForButtonBar(Composite parent) {
		// create OK and Cancel buttons by default
		okButton = createButton(parent, IDialogConstants.OK_ID, IDialogConstants.OK_LABEL, true);
		createButton(parent, IDialogConstants.CANCEL_ID, IDialogConstants.CANCEL_LABEL, false);

		//do this here because setting the text will set enablement on the ok
		// button
		text.setFocus();
		if (value != null) {
			text.setText(value);
			text.selectAll();
		}
	}

	/*
	 * (non-Javadoc) Method declared on Dialog.
	 */
	protected Control createDialogArea(Composite parent) {
		// create composite
		Composite composite = (Composite) super.createDialogArea(parent);

		// create message
		if (message != null) {
			Label label = new Label(composite, SWT.WRAP);
			label.setText(message);
			GridData data = new GridData(GridData.GRAB_HORIZONTAL | GridData.GRAB_VERTICAL | GridData.HORIZONTAL_ALIGN_FILL | GridData.VERTICAL_ALIGN_CENTER);
			data.widthHint = convertHorizontalDLUsToPixels(IDialogConstants.MINIMUM_MESSAGE_AREA_WIDTH);
			label.setLayoutData(data);
			label.setFont(parent.getFont());
		}

		text = new Text(composite, SWT.SINGLE | SWT.BORDER);
		text.setLayoutData(new GridData(GridData.GRAB_HORIZONTAL | GridData.HORIZONTAL_ALIGN_FILL));
		text.addModifyListener(new ModifyListener() {
			public void modifyText(ModifyEvent e) {
				validateInput();
			}
		});
		text.setFont(parent.getFont());

		errorMessageLabel = new Text(composite, SWT.READ_ONLY);
		errorMessageLabel.setLayoutData(new GridData(GridData.GRAB_HORIZONTAL | GridData.HORIZONTAL_ALIGN_FILL));
		errorMessageLabel.setFont(parent.getFont());

		return composite;
	}

	/**
	 * Returns the error message text widget.
	 * 
	 * @return the error message text widget
	 */
	protected Text getErrorMessageLabel() {
		return errorMessageLabel;
	}

	/**
	 * Returns the ok button.
	 * 
	 * @return the ok button
	 */
	protected Button getOkButton() {
		return okButton;
	}

	/**
	 * Returns the text area.
	 * 
	 * @return the text area
	 */
	protected Text getText() {
		return text;
	}

	/**
	 * Returns the validator.
	 * 
	 * @return the validator
	 */
	protected IInputValidator getValidator() {
		return validator;
	}

	/**
	 * Returns the string typed into this input dialog.
	 * 
	 * @return the input string
	 */
	public String getValue() {
		return value;
	}

	/**
	 * Validates the input.
	 * <p>
	 * The default implementation of this framework method delegates the
	 * request to the supplied input validator object; if it finds the input
	 * invalid, the error message is displayed in the dialog's message line.
	 * This hook method is called whenever the text changes in the input
	 * field.
	 * </p>
	 */
	protected void validateInput() {

		String errorMessage = null;

		if (validator != null) {
			errorMessage = validator.isValid(text.getText());
		}

		// Bug 16256: important not to treat "" (blank error) the same as null
		// (no error)
		errorMessageLabel.setText(errorMessage == null ? "" : errorMessage); //$NON-NLS-1$
		okButton.setEnabled(errorMessage == null);

		errorMessageLabel.getParent().update();
	}
}