/*
 * Copyright 2013-2014, Stephan Aßmus <superstippi@gmx.de>.
 * All rights reserved. Distributed under the terms of the MIT License.
 */


#include "ScrollableGroupView.h"

#include <ScrollBar.h>
#include <SpaceLayoutItem.h>


ScrollableGroupView::ScrollableGroupView()
        :
        BGroupView(B_VERTICAL, 0.0)
{
        AddChild(BSpaceLayoutItem::CreateGlue());
}


BSize
ScrollableGroupView::MinSize()
{
        BSize minSize = BGroupView::MinSize();
        return BSize(minSize.width, 80);
}


void
ScrollableGroupView::DoLayout()
{
        BGroupView::DoLayout();

        BScrollBar* scrollBar = ScrollBar(B_VERTICAL);

        if (scrollBar == NULL)
                return;

        BRect layoutArea = GroupLayout()->LayoutArea();
        float layoutHeight = layoutArea.Height();
        // Min size is not reliable with HasHeightForWidth() children,
        // since it does not reflect how those children are currently
        // laid out, but what their theoretical minimum size would be.

        BLayoutItem* lastItem = GroupLayout()->ItemAt(
                GroupLayout()->CountItems() - 1);
        if (lastItem != NULL)
                layoutHeight = lastItem->Frame().bottom;

        float viewHeight = Bounds().Height();

        float max = layoutHeight- viewHeight;
        scrollBar->SetRange(0, max);
        if (layoutHeight > 0)
                scrollBar->SetProportion(viewHeight / layoutHeight);
        else
                scrollBar->SetProportion(1);
}