package com.temp.foundation.client.widget;

import com.google.gwt.event.dom.client.*;
import com.google.gwt.user.client.ui.*;
import com.temp.common.shared.utils.*;

public class PageHeader extends AbstractHorizontalLabeledPageWidget {
    private static final String PAGE_HEADER_STYLE_NAME = "page-header";
    private static final String TITLE_STYLE_NAME = "page-header-title";
    public static final String DESCRIPTION_STYLE_NAME = "section-description";

    private final VerticalPanel overallVerticalPanel = new VerticalPanel();
    private final VerticalPanel leftPanel = new VerticalPanel();
    private final VerticalPanel rightPanel = new VerticalPanel();
    private Label descriptionLabel;
    private Label bottomDescriptionLabel;

    public PageHeader() {
        super( PAGE_HEADER_STYLE_NAME, TITLE_STYLE_NAME );

        overallVerticalPanel.setWidth( "100%" );
        horizontalPanel.add( overallVerticalPanel );
        HorizontalPanel innerHorizontalPanel = new HorizontalPanel();
        overallVerticalPanel.add( innerHorizontalPanel );

        innerHorizontalPanel.add( leftPanel );
        innerHorizontalPanel.add( new LeftRightSiblings( false ) );
        innerHorizontalPanel.add( rightPanel );

        leftPanel.add( titleLabel );
    }

    public void setDescription( String description ) {
        descriptionLabel = setLabelAsDescription( leftPanel, descriptionLabel, description );
    }

    public void setBottomDescription( String description ) {
        bottomDescriptionLabel = setLabelAsDescription( overallVerticalPanel, bottomDescriptionLabel, description );
    }

    public VerticalPanel getLeftPanel() {
        return leftPanel;
    }

    public VerticalPanel getRightPanel() {
        return rightPanel;
    }

    public CompositeButton addButton( String name, ClickHandler clickHandler ) {
        return addButton( new OurPushButton( name, clickHandler ) );
    }

    public CompositeButton addButton( CompositeButton button ) {
        if ( rightPanel.getWidgetCount() > 0 ) {
            rightPanel.add( new Spacer() );
        }
        rightPanel.add( button );
        return button;
    }

    /**
     * Since "some" of the Browsers will treat a "table cell" that contains an
     * empty DIV (label) as if it does not implicitly get a 1em space when all
     * it contains is an empty label. So if the description is null or empty,
     * then the label must be removed!
     */
    private static Label setLabelAsDescription( VerticalPanel parent, Label label, String description ) {
        description = StringUtils.noEmpty( description );
        if ( description == null ) {
            return removeDescriptionLabel( parent, label );
        }
        label = insureDescriptionLabel( parent, label );
        label.setText( description );
        return label;
    }

    private static Label insureDescriptionLabel( VerticalPanel parent, Label label ) {
        if ( label == null ) {
            label = new Label();
            label.setStyleName( DESCRIPTION_STYLE_NAME );
            parent.add( label );
        }
        return label;
    }

    private static Label removeDescriptionLabel( VerticalPanel parent, Label label ) {
        if ( label != null ) {
            parent.remove( label );
        }
        return null;
    }
}