//========= Copyright (c) 1996-2002, Valve LLC, All rights reserved. ============
//
// Purpose: 
//
// $NoKeywords: $
//=============================================================================

#include "vgui_listbox.h"

using namespace vgui;

CListBox::CListBox() : Panel( 0, 0, 0, 0 ),
	m_ItemsPanel( 0, 0, 0, 0 ),
	m_ScrollBar( 0, 0, 0, 0, true ),
	m_Slider( 0, 0, 10, 40, true )
{
	m_Signal.m_pListBox = this;

	m_ItemsPanel.setParent( this );
	m_ItemsPanel.setBgColor( 0, 0, 0, 255 );

	m_Slider.setRangeWindow( 50 );
	m_Slider.setRangeWindowEnabled( true );

	m_ScrollBar.setParent( this );
	m_ScrollBar.addIntChangeSignal( &m_Signal );
	m_ScrollBar.setSlider( &m_Slider );
	m_ScrollBar.setButtonPressedScrollValue( 1 );

	m_Items.m_pNext = m_Items.m_pPrev = &m_Items;
	m_ItemOffset = 0;
	m_iScrollMax = -1;
}

CListBox::~CListBox()
{
	Term();
}

void CListBox::Init()
{
	Term();
}

void CListBox::Term()
{
	m_ItemOffset = 0;

	// Free the LBItems.
	LBItem *pNext;

	for( LBItem *pItem =m_Items.m_pNext; pItem != &m_Items; pItem = pNext )
	{
		pItem->m_pPanel->setParent( NULL );	// detach the panel from us
		pNext = pItem->m_pNext;
		delete pItem;
	}
	m_Items.m_pPrev = m_Items.m_pNext = &m_Items;
}

void CListBox::AddItem( Panel *panel )
{
	// Add the item.
	LBItem *pItem = new LBItem;
	if( !pItem )
		return;

	pItem->m_pPanel = panel;
	pItem->m_pPanel->setParent( &m_ItemsPanel );

	pItem->m_pPrev = m_Items.m_pPrev;
	pItem->m_pNext = &m_Items;
	pItem->m_pNext->m_pPrev = pItem->m_pPrev->m_pNext = pItem;	

	m_ScrollBar.setRange( 0, GetScrollMax() );
	m_Slider.setRangeWindow( 50 );
	m_Slider.setRangeWindowEnabled( true );

	InternalLayout();
}

int CListBox::GetNumItems()
{
	int count = 0;

	for( LBItem *pItem = m_Items.m_pNext; pItem != &m_Items; pItem = pItem->m_pNext )
		++count;

	return count;
}

int CListBox::GetItemWidth()
{
	int wide, tall;

	m_ItemsPanel.getSize( wide, tall );

	return wide;
}

int CListBox::GetScrollPos()
{
	return m_ItemOffset;
}

void CListBox::SetScrollPos( int pos )
{
	int maxItems = GetScrollMax();
	if( maxItems < 0 )
		return;

	m_ItemOffset = ( pos < 0 ) ? 0 : ( ( pos > maxItems ) ? maxItems : pos );
	InternalLayout();
}

void CListBox::setPos( int x, int y )
{
	Panel::setPos( x, y );
	InternalLayout();
}

void CListBox::setSize( int wide, int tall )
{
	Panel::setSize( wide, tall );
	InternalLayout();
}

void CListBox::setPixelScroll( int value )
{
	m_ItemOffset = m_ScrollBar.getValue();
	InternalLayout();
}

void CListBox::InternalLayout()
{
	int x, y, wide, tall;
	getBounds( x, y, wide, tall );

	// Reposition the main panel and the scrollbar.
	m_ItemsPanel.setBounds( 0, 0, wide - 15, tall );
	m_ScrollBar.setBounds( wide - 15, 0, 15, tall );

	bool bNeedScrollbar = false;

	// Reposition the items.
	int curItem = 0;
	int curY = 0;
	int maxItem = GetScrollMax();
	for( LBItem *pItem = m_Items.m_pNext; pItem != &m_Items; pItem = pItem->m_pNext )
	{
		if( curItem < m_ItemOffset )
		{
			pItem->m_pPanel->setVisible( false );
			bNeedScrollbar = true;
		}
		else if( curItem >= maxItem )
		{
			// item is past the end of the items we care about
			pItem->m_pPanel->setVisible( false );
		}
		else
		{
			pItem->m_pPanel->setVisible( true );

			int itemWidth, itemHeight;

			pItem->m_pPanel->getSize( itemWidth, itemHeight );

			// Don't change the item's height but change its width to fit the listbox.
			pItem->m_pPanel->setBounds( 0, curY, wide, itemHeight );

			curY += itemHeight;

			if( curY > tall )
			{
				bNeedScrollbar = true;
			}
		}

		++curItem;
	}

	m_ScrollBar.setVisible( bNeedScrollbar );

	repaint();
}

void CListBox::paintBackground()
{
}

void CListBox::SetScrollRange( int maxScroll )
{
	m_iScrollMax = maxScroll;
	m_ScrollBar.setRange( 0, maxScroll );
	InternalLayout();
}

int CListBox::GetScrollMax()
{
	if( m_iScrollMax < 0 )
	{
		return GetNumItems() - 1;
	}

	return m_iScrollMax;
}