/*  Preview.cpp
 *
 *  Copyright (C) 2013-2016  Jim Evins <evins@snaught.com>
 *
 *  This file is part of gLabels-qt.
 *
 *  gLabels-qt is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  gLabels-qt is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with gLabels-qt.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "Preview.h"


#include <QGraphicsDropShadowEffect>
#include <QGraphicsRectItem>
#include <QtDebug>

#include "LabelModel.h"
#include "PreviewOverlayItem.h"


//
// Private Configuration Data
//
namespace
{
        const QColor  paperColor( 255, 255, 255 );
        const QColor  paperOutlineColor( 0, 0, 0 );
	const double  paperOutlineWidthPixels = 1;

        const QColor  shadowColor( 64, 64, 64 );
	const double  shadowOffsetPixels = 3;
	const double  shadowRadiusPixels = 12;

        const QColor  labelColor( 255, 255, 255 );
        const QColor  labelOutlineColor( 215, 215, 215 );
	const double  labelOutlineWidthPixels = 1;
}


///
/// Constructor
///
Preview::Preview( QWidget *parent )
	: mModel(0), mRenderer(0), QGraphicsView(parent)
{
	mScene = new QGraphicsScene();
	setScene( mScene );

	setAttribute(Qt::WA_TranslucentBackground);
	viewport()->setAutoFillBackground(false);

	setFrameStyle( QFrame::NoFrame );
	setRenderHints( QPainter::Antialiasing );
}


///
/// Set renderer
///
void Preview::setRenderer( const PageRenderer* renderer )
{
	mRenderer = renderer;

	connect( mRenderer, SIGNAL(changed()), this, SLOT(onRendererChanged()) );
	onRendererChanged();
}


///
/// Renderer changed handler
///
void Preview::onRendererChanged()
{
	mModel = mRenderer->model();

	clearScene();

	if ( mModel != NULL )
	{
		// Set scene up with a 5% margin around paper
		glabels::Distance x = -0.05 * mModel->tmplate()->pageWidth();
		glabels::Distance y = -0.05 * mModel->tmplate()->pageHeight();
		glabels::Distance w = 1.10 * mModel->tmplate()->pageWidth();
		glabels::Distance h = 1.10 * mModel->tmplate()->pageHeight();

		mScene->setSceneRect( x.pt(), y.pt(), w.pt(), h.pt() );
		fitInView( mScene->sceneRect(), Qt::KeepAspectRatio );

		drawPaper( mModel->tmplate()->pageWidth(), mModel->tmplate()->pageHeight() );
		drawLabels();
		drawPreviewOverlay();
	}
}


///
/// Resize Event Handler
///
void Preview::resizeEvent( QResizeEvent* event )
{
	fitInView( mScene->sceneRect(), Qt::KeepAspectRatio );
}


///
/// Clear View
///
void Preview::clearScene()
{
	foreach ( QGraphicsItem *item, mScene->items() )
	{
		mScene->removeItem( item );
		delete item;
	}
}


///
/// Draw Paper
///
void Preview::drawPaper( const glabels::Distance& pw, const glabels::Distance& ph )
{
	QGraphicsDropShadowEffect *shadowEffect = new QGraphicsDropShadowEffect();
	shadowEffect->setColor( shadowColor );
	shadowEffect->setOffset( shadowOffsetPixels );
	shadowEffect->setBlurRadius( shadowRadiusPixels );

	QBrush brush( paperColor );
	QPen pen( paperOutlineColor );
	pen.setCosmetic( true );
	pen.setWidthF( paperOutlineWidthPixels );

	QGraphicsRectItem *pageItem = new QGraphicsRectItem( 0, 0, pw.pt(), ph.pt() );
	pageItem->setBrush( brush );
	pageItem->setPen( pen );
	pageItem->setGraphicsEffect( shadowEffect );
				
	mScene->addItem( pageItem );
}


///
/// Draw Labels on Paper
///
void Preview::drawLabels()
{
	glabels::Frame *frame = mModel->tmplate()->frames().first();

	foreach (glabels::Point origin, frame->getOrigins() )
	{
		drawLabel( origin.x(), origin.y(), frame->path() );
	}
}


///
/// Draw a Single Label at x,y
///
void Preview::drawLabel( const glabels::Distance& x,
			 const glabels::Distance& y,
			 const QPainterPath&      path )
{
	QBrush brush( Qt::NoBrush );
	QPen pen( labelOutlineColor );
	pen.setStyle( Qt::DotLine );
	pen.setCosmetic( true );
	pen.setWidthF( labelOutlineWidthPixels );

	QGraphicsPathItem *labelOutlineItem  = new QGraphicsPathItem( path );
	labelOutlineItem->setBrush( brush );
	labelOutlineItem->setPen( pen );
	labelOutlineItem->setPos( x.pt(), y.pt() );

	mScene->addItem( labelOutlineItem );
}


///
/// Draw Preview Overlay
///
void Preview::drawPreviewOverlay()
{
	if ( mRenderer )
	{
		PreviewOverlayItem* overlayItem = new PreviewOverlayItem( mRenderer );
		mScene->addItem( overlayItem );
	}
}