/*******************************************************************************
 * Copyright (c) 2000, 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
 *******************************************************************************/
package org.erlide.ui.dialogs.fields;

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

public final class LayoutUtil {

    private LayoutUtil() {
    }

    /**
     * Calculates the number of columns needed by field editors
     */
    public static int getNumberOfColumns(final DialogField[] editors) {
        int nCulumns = 0;
        for (final DialogField element : editors) {
            nCulumns = Math.max(element.getNumberOfControls(), nCulumns);
        }
        return nCulumns;
    }

    /**
     * Creates a composite and fills in the given editors.
     *
     * @param labelOnTop
     *            Defines if the label of all fields should be on top of the
     *            fields
     */
    public static void doDefaultLayout(final Composite parent,
            final DialogField[] editors, final boolean labelOnTop) {
        doDefaultLayout(parent, editors, labelOnTop, 0, 0);
    }

    /**
     * Creates a composite and fills in the given editors.
     *
     * @param labelOnTop
     *            Defines if the label of all fields should be on top of the
     *            fields
     * @param marginWidth
     *            The margin width to be used by the composite
     * @param marginHeight
     *            The margin height to be used by the composite
     */
    public static void doDefaultLayout(final Composite parent,
            final DialogField[] editors, final boolean labelOnTop, final int marginWidth,
            final int marginHeight) {
        int nColumns = getNumberOfColumns(editors);
        final Control[][] controls = new Control[editors.length][];
        for (int i = 0; i < editors.length; i++) {
            controls[i] = editors[i].doFillIntoGrid(parent, nColumns);
        }
        if (labelOnTop) {
            nColumns--;
            modifyLabelSpans(controls, nColumns);
        }
        GridLayout layout = null;
        if (parent.getLayout() instanceof GridLayout) {
            layout = (GridLayout) parent.getLayout();
        } else {
            layout = new GridLayout();
        }
        if (marginWidth != SWT.DEFAULT) {
            layout.marginWidth = marginWidth;
        }
        if (marginHeight != SWT.DEFAULT) {
            layout.marginHeight = marginHeight;
        }
        layout.numColumns = nColumns;
        parent.setLayout(layout);
    }

    private static void modifyLabelSpans(final Control[][] controls, final int nCulumns) {
        for (final Control[] element : controls) {
            setHorizontalSpan(element[0], nCulumns);
        }
    }

    /**
     * Sets the span of a control. Assumes that GridData is used.
     */
    public static void setHorizontalSpan(final Control control, final int span) {
        final Object ld = control.getLayoutData();
        if (ld instanceof GridData) {
            ((GridData) ld).horizontalSpan = span;
        } else if (span != 1) {
            final GridData gd = new GridData();
            gd.horizontalSpan = span;
            control.setLayoutData(gd);
        }
    }

    /**
     * Sets the width hint of a control. Assumes that GridData is used.
     */
    public static void setWidthHint(final Control control, final int widthHint) {
        final Object ld = control.getLayoutData();
        if (ld instanceof GridData) {
            ((GridData) ld).widthHint = widthHint;
        }
    }

    /**
     * Sets the heightHint hint of a control. Assumes that GridData is used.
     */
    public static void setHeightHint(final Control control, final int heightHint) {
        final Object ld = control.getLayoutData();
        if (ld instanceof GridData) {
            ((GridData) ld).heightHint = heightHint;
        }
    }

    /**
     * Sets the horizontal indent of a control. Assumes that GridData is used.
     */
    public static void setHorizontalIndent(final Control control,
            final int horizontalIndent) {
        final Object ld = control.getLayoutData();
        if (ld instanceof GridData) {
            ((GridData) ld).horizontalIndent = horizontalIndent;
        }
    }

    /**
     * Sets the horizontal grabbing of a control to true. Assumes that GridData
     * is used.
     */
    public static void setHorizontalGrabbing(final Control control) {
        final Object ld = control.getLayoutData();
        if (ld instanceof GridData) {
            ((GridData) ld).grabExcessHorizontalSpace = true;
        }
    }

}