/*  SimplePreview.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 "SimplePreview.h"

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


namespace glabels
{

	//
	// Private
	//
	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( 128, 128, 255 );
		const double  labelOutlineWidthPixels = 2;

		const QColor  arrowColor( 192, 192, 255, 128 );
		const double  arrowScale = 0.35;

		const QColor  upColor( 192, 192, 255, 128 );
		const double  upScale = 0.15;
		const QString upFontFamily( "Sans" );
	}


	///
	/// Constructor
	///
	SimplePreview::SimplePreview( QWidget *parent )
		: mTmplate(nullptr), mRotateFlag(false), QGraphicsView(parent)
	{
		mScene = new QGraphicsScene();
		setScene( mScene );

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

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


	///
	/// Template Property Setter
	///
	void SimplePreview::setTemplate( const Template *tmplate )
	{
		mTmplate = tmplate;
		update();
	}


	///
	/// Rotate Property Setter
	///
	void SimplePreview::setRotate( bool rotateFlag )
	{
		mRotateFlag = rotateFlag;
		update();
	}


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


	///
	/// Update View
	///
	void SimplePreview::update()
	{
		clearScene();

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

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

			drawPaper( mTmplate->pageWidth(), mTmplate->pageHeight() );
			drawLabels();
			drawArrow();
		}
	}


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


	///
	/// Draw Paper
	///
	void SimplePreview::drawPaper( const Distance& pw, const 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 SimplePreview::drawLabels()
	{
		Frame *frame = mTmplate->frames().first();

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


	///
	/// Draw a Single Label at x,y
	///
	void SimplePreview::drawLabel( const Distance&     x,
	                               const Distance&     y,
	                               const QPainterPath& path )
	{
		QBrush brush( labelColor );
		QPen pen( labelOutlineColor );
		pen.setCosmetic( true );
		pen.setWidthF( labelOutlineWidthPixels );

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

		mScene->addItem( labelItem );
	}


	///
	/// Draw Arrow Indicating Top of First Label
	///
	void SimplePreview::drawArrow()
	{
		Frame *frame = mTmplate->frames().first();

		Distance w = frame->w();
		Distance h = frame->h();

		Distance minWH = min( w, h );

		QPen pen( arrowColor );
		pen.setWidthF( 0.25*minWH.pt()*arrowScale );
		pen.setCapStyle( Qt::FlatCap );
		pen.setJoinStyle( Qt::MiterJoin );

		QBrush brush( upColor );

		Point origin = frame->getOrigins().first();
		Distance x0 = origin.x();
		Distance y0 = origin.y();

		QPainterPath path;
		path.moveTo( 0,                         minWH.pt()*arrowScale/3 );
		path.lineTo( 0,                        -minWH.pt()*arrowScale   );
		path.moveTo( -minWH.pt()*arrowScale/2, -minWH.pt()*arrowScale/2 );
		path.lineTo( 0,                        -minWH.pt()*arrowScale   );
		path.lineTo(  minWH.pt()*arrowScale/2, -minWH.pt()*arrowScale/2 );

		QGraphicsPathItem *arrowItem = new QGraphicsPathItem( path );
		arrowItem->setPen( pen );
		arrowItem->setPos( (x0+w/2).pt(), (y0+h/2).pt() );
		if ( mRotateFlag )
		{
			arrowItem->setRotation( -90 );
		}

		QGraphicsSimpleTextItem *upItem = new QGraphicsSimpleTextItem( tr("Up") );
		upItem->setBrush( brush );
		upItem->setFont( QFont( upFontFamily, minWH.pt()*upScale, QFont::Bold ) );
		upItem->setPos( (x0+w/2).pt(), (y0+h/2).pt() );
		QRectF rect = upItem->boundingRect();
		if ( mRotateFlag )
		{
			upItem->setPos( upItem->x()+minWH.pt()/8, upItem->y()+rect.width()/2 );
			upItem->setRotation( -90 );
		}
		else
		{
			upItem->setPos( upItem->x()-rect.width()/2, upItem->y()+minWH.pt()/8 );
		}

		mScene->addItem( arrowItem );
		mScene->addItem( upItem );
	}

} // namespace glabels