#include "instancedelegate.h"
#include <QPainter>
#include <QTextOption>
#include <QTextLayout>
#include <QApplication>
#include <QtCore/qmath.h>

// Origin: Qt
static void viewItemTextLayout ( QTextLayout &textLayout, int lineWidth, qreal &height, qreal &widthUsed )
{
	height = 0;
	widthUsed = 0;
	textLayout.beginLayout();
	QString str = textLayout.text();
	while ( true )
	{
		QTextLine line = textLayout.createLine();
		if ( !line.isValid() )
			break;
		if(line.textLength() == 0)
			break;
		line.setLineWidth ( lineWidth );
		line.setPosition ( QPointF ( 0, height ) );
		height += line.height();
		widthUsed = qMax ( widthUsed, line.naturalTextWidth() );
	}
	textLayout.endLayout();
}

#define QFIXED_MAX (INT_MAX/256)

ListViewDelegate::ListViewDelegate ( QObject* parent ) : QStyledItemDelegate ( parent )
{

}

void drawSelectionRect(QPainter *painter, const QStyleOptionViewItemV4 &option, const QRect &rect)
{
	if ((option.state & QStyle::State_Selected))
		painter->fillRect ( rect, option.palette.brush ( QPalette::Highlight ) );
	else
	{
		QColor backgroundColor = option.palette.color(QPalette::Background);
		backgroundColor.setAlpha(160);
		painter->fillRect ( rect, QBrush(backgroundColor) );
	}

}

void drawFocusRect(QPainter *painter, const QStyleOptionViewItemV4 &option, const QRect &rect)
{
	if (!(option.state & QStyle::State_HasFocus))
		return;
	QStyleOptionFocusRect opt;
	opt.direction       = option.direction;
	opt.fontMetrics     = option.fontMetrics;
	opt.palette         = option.palette;
	opt.rect            = rect;
	//opt.state           = option.state | QStyle::State_KeyboardFocusChange | QStyle::State_Item;
	auto col = option.state & QStyle::State_Selected ? QPalette::Highlight : QPalette::Base;
	opt.backgroundColor = option.palette.color(col);
	// Apparently some widget styles expect this hint to not be set
	painter->setRenderHint(QPainter::Antialiasing, false);

	QStyle *style = option.widget ? option.widget->style() : QApplication::style();

	style->drawPrimitive(QStyle::PE_FrameFocusRect, &opt, painter, option.widget);

	painter->setRenderHint(QPainter::Antialiasing);
}

static QSize viewItemTextSize ( const QStyleOptionViewItemV4 *option )
{
	QStyle *style = option->widget ? option->widget->style() : QApplication::style();
	QTextOption textOption;
	textOption.setWrapMode ( QTextOption::WrapAtWordBoundaryOrAnywhere );
	QTextLayout textLayout;
	textLayout.setTextOption ( textOption );
	textLayout.setFont ( option->font );
	textLayout.setText ( option->text );
	const int textMargin = style->pixelMetric ( QStyle::PM_FocusFrameHMargin, option, option->widget ) + 1;
	QRect bounds ( 0,0,100 - 2*textMargin,600 );
	qreal height = 0, widthUsed = 0;
	viewItemTextLayout ( textLayout, bounds.width(), height, widthUsed );
	const QSize size ( qCeil ( widthUsed ), qCeil ( height ) );
	return QSize ( size.width() + 2 * textMargin, size.height() );
}

void ListViewDelegate::paint ( QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index ) const
{
	QStyleOptionViewItemV4 opt = option;
	initStyleOption ( &opt, index );
	painter->save();
	painter->setClipRect ( opt.rect );

	opt.features |= QStyleOptionViewItem::WrapText;
	opt.text = index.data().toString();
	opt.textElideMode = Qt::ElideRight;
	opt.displayAlignment = Qt::AlignTop | Qt::AlignHCenter;

	QStyle *style = opt.widget ? opt.widget->style() : QApplication::style();

	//const int iconSize =  style->pixelMetric(QStyle::PM_IconViewIconSize);
	const int iconSize = 48;
	QRect iconbox = opt.rect;
	const int textMargin = style->pixelMetric ( QStyle::PM_FocusFrameHMargin, 0, opt.widget ) + 1;
	QRect textRect = opt.rect;
	QRect textHighlightRect = textRect;
	// clip the decoration on top, remove width padding
	textRect.adjust ( textMargin,iconSize + textMargin + 5,-textMargin,0 );
	
	textHighlightRect.adjust ( 0,iconSize + 5,0,0 );

	// draw background
	{
		QSize textSize = viewItemTextSize ( &opt );
		QPalette::ColorGroup cg;
		QStyleOptionViewItemV4 opt2(opt);
		
		if((opt.widget && opt.widget->isEnabled()) || (opt.state & QStyle::State_Enabled))
		{
			if(! ( opt.state & QStyle::State_Active ))
				cg = QPalette::Inactive;
			else
				cg = QPalette::Normal;
		}
		else
		{
			cg = QPalette::Disabled;
		}
		opt2.palette.setCurrentColorGroup(cg);
		
		// fill in background, if any
		if ( opt.backgroundBrush.style() != Qt::NoBrush )
		{
			QPointF oldBO = painter->brushOrigin();
			painter->setBrushOrigin ( opt.rect.topLeft() );
			painter->fillRect ( opt.rect, opt.backgroundBrush );
			painter->setBrushOrigin ( oldBO );
		}
		
		if ( opt.showDecorationSelected )
		{
			drawSelectionRect(painter,opt2, opt.rect);
			drawFocusRect(painter,opt2, opt.rect);
			//painter->fillRect ( opt.rect, opt.palette.brush ( cg, QPalette::Highlight ) );
		}
		else
		{
			
			//if ( opt.state & QStyle::State_Selected )
			{
				//QRect textRect = subElementRect ( QStyle::SE_ItemViewItemText,  opt, opt.widget );
				//painter->fillRect ( textHighlightRect, opt.palette.brush ( cg, QPalette::Highlight ) );
				drawSelectionRect(painter,opt2, textHighlightRect);
				drawFocusRect(painter,opt2, textHighlightRect);
			}
		}
	}

	// draw the icon
	{
		QIcon::Mode mode = QIcon::Normal;
		if ( ! ( opt.state & QStyle::State_Enabled ) )
			mode = QIcon::Disabled;
		else if ( opt.state & QStyle::State_Selected )
			mode = QIcon::Selected;
		QIcon::State state = opt.state & QStyle::State_Open ? QIcon::On : QIcon::Off;

		iconbox.setHeight ( iconSize );
		opt.icon.paint ( painter, iconbox, Qt::AlignCenter, mode, state );
	}
	// set the text colors
	QPalette::ColorGroup cg = opt.state & QStyle::State_Enabled ? QPalette::Normal : QPalette::Disabled;
	if ( cg == QPalette::Normal && ! ( opt.state & QStyle::State_Active ) )
		cg = QPalette::Inactive;
	if ( opt.state & QStyle::State_Selected )
	{
		painter->setPen ( opt.palette.color ( cg, QPalette::HighlightedText ) );
	}
	else
	{
		painter->setPen ( opt.palette.color ( cg, QPalette::Text ) );
	}

	// draw the text
	QTextOption textOption;
	textOption.setWrapMode ( QTextOption::WrapAtWordBoundaryOrAnywhere );
	textOption.setTextDirection ( opt.direction );
	textOption.setAlignment ( QStyle::visualAlignment ( opt.direction, opt.displayAlignment ) );
	QTextLayout textLayout;
	textLayout.setTextOption ( textOption );
	textLayout.setFont ( opt.font );
	textLayout.setText ( opt.text );

	qreal width, height;
	viewItemTextLayout ( textLayout, textRect.width(), height, width );

	const int lineCount = textLayout.lineCount();

	const QRect layoutRect = QStyle::alignedRect ( opt.direction, opt.displayAlignment, QSize ( textRect.width(), int ( height ) ), textRect );
	const QPointF position = layoutRect.topLeft();
	for ( int i = 0; i < lineCount; ++i )
	{
		const QTextLine line = textLayout.lineAt ( i );
		line.draw ( painter, position );
	}

	painter->restore();
}


QSize ListViewDelegate::sizeHint ( const QStyleOptionViewItem & option, const QModelIndex & index ) const
{
	QStyleOptionViewItemV4 opt = option;
	initStyleOption ( &opt, index );
	opt.features |= QStyleOptionViewItem::WrapText;
	opt.text = index.data().toString();
	opt.textElideMode = Qt::ElideRight;
	opt.displayAlignment = Qt::AlignTop | Qt::AlignHCenter;

	QStyle *style = opt.widget ? opt.widget->style() : QApplication::style();
	const int textMargin = style->pixelMetric ( QStyle::PM_FocusFrameHMargin, &option, opt.widget ) + 1;
	int height = 48 + textMargin * 2 + 5; // TODO: turn constants into variables
	QSize szz = viewItemTextSize ( &opt );
	height += szz.height();
	// FIXME: maybe the icon items could scale and keep proportions?
	QSize sz ( 100,height );
	return sz;
}