/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.preference;

import org.eclipse.jface.util.Assert;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.*;

/**
 * A field editor for an enumeration type preference.
 * The choices are presented as a list of radio buttons.
 */
public class RadioGroupFieldEditor extends FieldEditor {

	/**
	 * List of radio button entries of the form [label,value].
	 */
	private String[][] labelsAndValues;

	/**
	 * Number of columns into which to arrange the radio buttons.
	 */
	private int numColumns;

	/**
	 * Indent used for the first column of the radion button matrix.
	 */
	private int indent = HORIZONTAL_GAP;

	/**
	 * The current value, or <code>null</code> if none.
	 */
	private String value;

	/**
	 * The box of radio buttons, or <code>null</code> if none
	 * (before creation and after disposal).
	 */
	private Composite radioBox;

	/**
	 * The radio buttons, or <code>null</code> if none
	 * (before creation and after disposal).
	 */
	private Button[] radioButtons;
	
	/**
	 * Whether to use a Group control.
	 */
	private boolean useGroup;
/**
 * Creates a new radio group field editor 
 */
protected RadioGroupFieldEditor() {
}
/**
 * Creates a radio group field editor.  
 * This constructor does not use a <code>Group</code> to contain the radio buttons.
 * It is equivalent to using the following constructor with <code>false</code>
 * for the <code>useGroup</code> argument.
 * <p>
 * Example usage:
 * <pre>
 *		RadioGroupFieldEditor editor= new RadioGroupFieldEditor(
 *			"GeneralPage.DoubleClick", resName, 1,
 *			new String[][] {
 *				{"Open Browser", "open"},
 *				{"Expand Tree", "expand"}
 *			},
 *          parent);	
 * </pre>
 * </p>
 * 
 * @param name the name of the preference this field editor works on
 * @param labelText the label text of the field editor
 * @param numColumns the number of columns for the radio button presentation
 * @param labelAndValues list of radio button [label, value] entries;
 *  the value is returned when the radio button is selected
 * @param parent the parent of the field editor's control
 */
public RadioGroupFieldEditor(String name, String labelText, int numColumns, String[][] labelAndValues, Composite parent) {
	this(name, labelText, numColumns, labelAndValues, parent, false);
}

/**
 * Creates a radio group field editor.
 * <p>
 * Example usage:
 * <pre>
 *		RadioGroupFieldEditor editor= new RadioGroupFieldEditor(
 *			"GeneralPage.DoubleClick", resName, 1,
 *			new String[][] {
 *				{"Open Browser", "open"},
 *				{"Expand Tree", "expand"}
 *			},
 *          parent,
 *          true);	
 * </pre>
 * </p>
 * 
 * @param name the name of the preference this field editor works on
 * @param labelText the label text of the field editor
 * @param numColumns the number of columns for the radio button presentation
 * @param labelAndValues list of radio button [label, value] entries;
 *  the value is returned when the radio button is selected
 * @param parent the parent of the field editor's control
 * @param useGroup whether to use a Group control to contain the radio buttons
 */
public RadioGroupFieldEditor(String name, String labelText, int numColumns, String[][] labelAndValues, Composite parent, boolean useGroup) {
	init(name, labelText);
	Assert.isTrue(checkArray(labelAndValues));
	this.labelsAndValues = labelAndValues;
	this.numColumns = numColumns;
	this.useGroup = useGroup;
	createControl(parent);
}
/* (non-Javadoc)
 * Method declared on FieldEditor.
 */
protected void adjustForNumColumns(int numColumns) {
	Control control = getLabelControl();
	if (control != null) {
		((GridData)control.getLayoutData()).horizontalSpan = numColumns;
	}
	((GridData)radioBox.getLayoutData()).horizontalSpan = numColumns;
}
/**
 * Checks whether given <code>String[][]</code> is of "type" 
 * <code>String[][2]</code>.
 *
 * @return <code>true</code> if it is ok, and <code>false</code> otherwise
 */
private boolean checkArray(String[][] table) {
	if (table == null)
		return false;
	for (int i = 0; i < table.length; i++) {
		String[] array = table[i];
		if (array == null || array.length != 2)
			return false;
	}
	return true;
}
/* (non-Javadoc)
 * Method declared on FieldEditor.
 */
protected void doFillIntoGrid(Composite parent, int numColumns) {
	if (useGroup) {
		Control control = getRadioBoxControl(parent);
		GridData gd = new GridData(GridData.FILL_HORIZONTAL);
		control.setLayoutData(gd);
	}
	else {
		Control control = getLabelControl(parent);
		GridData gd = new GridData();
		gd.horizontalSpan = numColumns;
		control.setLayoutData(gd);
		control = getRadioBoxControl(parent);
		gd = new GridData();
		gd.horizontalSpan = numColumns;
		gd.horizontalIndent = indent;
		control.setLayoutData(gd);
	}

}
/* (non-Javadoc)
 * Method declared on FieldEditor.
 */
protected void doLoad() {
	updateValue(getPreferenceStore().getString(getPreferenceName()));
}
/* (non-Javadoc)
 * Method declared on FieldEditor.
 */
protected void doLoadDefault() {
	updateValue(getPreferenceStore().getDefaultString(getPreferenceName()));
}
/* (non-Javadoc)
 * Method declared on FieldEditor.
 */
protected void doStore() {
	if (value == null) {
		getPreferenceStore().setToDefault(getPreferenceName());
		return;
	}

	getPreferenceStore().setValue(getPreferenceName(), value);
}
/* (non-Javadoc)
 * Method declared on FieldEditor.
 */
public int getNumberOfControls() {
	return 1;
}
/**
 * Returns this field editor's radio group control.
 *
 * @return the radio group control
 */
public Composite getRadioBoxControl(Composite parent) {
	if (radioBox == null) {
		
		Font font = parent.getFont();
		
		if (useGroup) {
			Group group = new Group(parent, SWT.NONE);
			group.setFont(font);
			String text = getLabelText();
			if (text != null)
				group.setText(text);
			radioBox = group;
			GridLayout layout = new GridLayout();
			layout.horizontalSpacing = HORIZONTAL_GAP;
			layout.numColumns = numColumns;
			radioBox.setLayout(layout);
		}
		else {
			radioBox = new Composite(parent, SWT.NONE);
			GridLayout layout = new GridLayout();
			layout.marginWidth = 0;
			layout.marginHeight = 0;
			layout.horizontalSpacing = HORIZONTAL_GAP;
			layout.numColumns = numColumns;
			radioBox.setLayout(layout);
			radioBox.setFont(font);
		}

		radioButtons = new Button[labelsAndValues.length];
		for (int i = 0; i < labelsAndValues.length; i++) {
			Button radio = new Button(radioBox, SWT.RADIO | SWT.LEFT);
			radioButtons[i] = radio;
			String[] labelAndValue = labelsAndValues[i];
			radio.setText(labelAndValue[0]);
			radio.setData(labelAndValue[1]);
			radio.setFont(font);
			radio.addSelectionListener(new SelectionAdapter() {
				public void widgetSelected(SelectionEvent event) {
					String oldValue = value;
					value = (String) event.widget.getData();
					setPresentsDefaultValue(false);
					fireValueChanged(VALUE, oldValue, value);
				}
			});
		}
		radioBox.addDisposeListener(new DisposeListener() {
			public void widgetDisposed(DisposeEvent event) {
				radioBox = null;
				radioButtons = null;
			}
		});
	} else {
		checkParent(radioBox, parent);
	}
	return radioBox;
}
/**
 * Sets the indent used for the first column of the radion button matrix.
 *
 * @param indent the indent (in pixels)
 */
public void setIndent(int indent) {
	if (indent < 0)
		this.indent = 0;
	else
		this.indent = indent;
}

/**
 * Select the radio button that conforms to the given value.
 *
 * @param selectedValue the selected value
 */
private void updateValue(String selectedValue) {
	this.value = selectedValue;
	if (radioButtons == null)
		return;

	if (this.value != null) {
		boolean found = false;
		for (int i = 0; i < radioButtons.length; i++) {
			Button radio = radioButtons[i];
			boolean selection = false;
			if (((String) radio.getData()).equals(this.value)) {
				selection = true;
				found = true;
			}
			radio.setSelection(selection);
		}
		if (found)
			return;
	}

	// We weren't able to find the value. So we select the first
	// radio button as a default.
	if (radioButtons.length > 0) {
		radioButtons[0].setSelection(true);
		this.value = (String) radioButtons[0].getData();
	}
	return;
}

/*
 * @see FieldEditor.setEnabled(boolean,Composite).
 */
public void setEnabled(boolean enabled, Composite parent){
	super.setEnabled(enabled,parent);
	for(int i = 0; i < radioButtons.length; i ++){
		radioButtons[i].setEnabled(enabled);
	}
}
}