/*******************************************************************************
 * Copyright (c) 2001, 2006 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.xml.ui.internal.preferences;

import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.wst.sse.core.internal.encoding.CommonCharsetNames;
import org.eclipse.wst.xml.ui.internal.XMLUIMessages;

/**
 * WorkbenchDefaultEncodingSettings is an extension of EncodingSettings. This
 * composite contains EncodingSettings for users to select the encoding they
 * desire as well as a checkbox for users to select to use the default
 * workbench encoding instead.
 * 
 * @see org.eclipse.wst.xml.ui.internal.preferences.EncodingSettings
 */
public class WorkbenchDefaultEncodingSettings extends Composite {

	private final static int INDENT = 15;
	private static final String WORKBENCH_DEFAULT = ""; //$NON-NLS-1$
	private EncodingSettings fEncodingSettings;
	private String fNonDefaultIANA = null;
	private Button fUseDefaultButton;

	public WorkbenchDefaultEncodingSettings(Composite parent) {
		super(parent, SWT.NONE);
		createControls();
	}

	private void createControls() {
		GridLayout layout = new GridLayout();
		layout.numColumns = 1;
		layout.marginWidth = 0;
		setLayout(layout);
		GridData data = new GridData();
		data.verticalAlignment = GridData.FILL;
		data.horizontalAlignment = GridData.FILL;
		data.grabExcessHorizontalSpace = true;
		setLayoutData(data);

		Composite defaultEncodingComposite = new Composite(this, SWT.NONE);
		layout = new GridLayout();
		layout.marginWidth = 0;
		layout.marginHeight = 0;
		data = new GridData(GridData.FILL_BOTH);
		defaultEncodingComposite.setLayout(layout);
		defaultEncodingComposite.setLayoutData(data);

		fUseDefaultButton = new Button(defaultEncodingComposite, SWT.CHECK);
		fUseDefaultButton.setText(XMLUIMessages.WorkbenchDefaultEncodingSettings_0);

		fUseDefaultButton.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent e) {
				handleUseDefaultButtonSelected();
			}
		});

		fEncodingSettings = new EncodingSettings(this);
		((GridLayout) fEncodingSettings.getLayout()).marginWidth = 0;
		((GridData) fEncodingSettings.getLayoutData()).horizontalIndent = INDENT;

	}

	private Combo getEncodingCombo() {
		return fEncodingSettings.getEncodingCombo();
	}

	/**
	 * <code>getIANATag</code> Get the IANA tag equivalent of the selected
	 * descriptive encoding name. Returns empty string if using workbench
	 * encoding.
	 * 
	 * @return a <code>String</code> value
	 */
	public String getIANATag() {
		if (!isDefault()) {
			return fEncodingSettings.getIANATag();
		}
		return WORKBENCH_DEFAULT;
	}

	private String getWorkbenchEncoding() {
		return ResourcesPlugin.getEncoding();
	}

	void handleUseDefaultButtonSelected() {
		if (fUseDefaultButton.getSelection()) {
			fNonDefaultIANA = fEncodingSettings.getIANATag();
			String workbenchValue = getWorkbenchEncoding();
			workbenchValue = CommonCharsetNames.getIanaPreferredCharsetName(workbenchValue);
			fEncodingSettings.setIANATag(workbenchValue);
		}
		else if (fNonDefaultIANA != null) {
			fEncodingSettings.setIANATag(fNonDefaultIANA);
		}
		getEncodingCombo().setEnabled(!fUseDefaultButton.getSelection());
		fEncodingSettings.setEnabled(!fUseDefaultButton.getSelection());
	}

	private boolean isDefault() {
		return fUseDefaultButton.getSelection();
	}

	/**
	 * <code>setEncoding</code> Set the selection in the combo to the
	 * descriptive encoding name. Selects use workbench encoding if ianaTag is
	 * null or empty string.
	 * 
	 */
	public void setIANATag(String ianaTag) {
		if ((ianaTag == null) || ianaTag.equals(WORKBENCH_DEFAULT)) {
			fUseDefaultButton.setSelection(true);
			handleUseDefaultButtonSelected();
		}
		else {
			fUseDefaultButton.setSelection(false);
			handleUseDefaultButtonSelected();
			if (!isDefault()) {
				fEncodingSettings.setIANATag(ianaTag);
			}
		}
	}
}