//===========================================
//  Lumina Desktop source code
//  Copyright (c) 2017, Ken Moore
//  Available under the 3-clause BSD license
//  See the LICENSE file for full details
//===========================================
// Simple subclass of QPrintPreviewWidget to provide
// notification when a context menu is requested
//===========================================
#ifndef _PRINT_GRAPHICS_H
#define _PRINT_GRAPHICS_H

#include <QMouseEvent>
#include <QDebug>
#include <QGraphicsView>
#include <QGraphicsItem>
#include <QBoxLayout>
#include <QScrollBar>
#include <QStyleOptionGraphicsItem>
#include <QtMath>
#include <QPrinter>
namespace {
class PageItem : public QGraphicsItem
{
public:
    PageItem(int _pageNum, const QImage _pagePicture, QSize _paperSize, QRect _pageRect)
        : pageNum(_pageNum), pagePicture(_pagePicture),
          paperSize(_paperSize), pageRect(_pageRect)
    {
        qreal border = qMax(paperSize.height(), paperSize.width()) / 25;
        brect = QRectF(QPointF(-border, -border),
                       QSizeF(paperSize)+QSizeF(2*border, 2*border));
        setCacheMode(DeviceCoordinateCache);
    }

    QRectF boundingRect() const Q_DECL_OVERRIDE
    { return brect; }

    inline int pageNumber() const
    { return pageNum; }

    void paint(QPainter *painter, const QStyleOptionGraphicsItem *item, QWidget *widget) Q_DECL_OVERRIDE;

private:
    int pageNum;
    const QImage pagePicture;
    QSize paperSize;
    QRect pageRect;
    QRectF brect;
};

void PageItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
  Q_UNUSED(widget);
  QRectF paperRect(0,0, paperSize.width(), paperSize.height());

  // Draw shadow
  painter->setClipRect(option->exposedRect);
  qreal shWidth = paperRect.width()/100;
  QRectF rshadow(paperRect.topRight() + QPointF(0, shWidth),
         paperRect.bottomRight() + QPointF(shWidth, 0));
  QLinearGradient rgrad(rshadow.topLeft(), rshadow.topRight());
  rgrad.setColorAt(0.0, QColor(0,0,0,255));
  rgrad.setColorAt(1.0, QColor(0,0,0,0));
  painter->fillRect(rshadow, QBrush(rgrad));
  QRectF bshadow(paperRect.bottomLeft() + QPointF(shWidth, 0),
         paperRect.bottomRight() + QPointF(0, shWidth));
  QLinearGradient bgrad(bshadow.topLeft(), bshadow.bottomLeft());
  bgrad.setColorAt(0.0, QColor(0,0,0,255));
  bgrad.setColorAt(1.0, QColor(0,0,0,0));
  painter->fillRect(bshadow, QBrush(bgrad));
  QRectF cshadow(paperRect.bottomRight(),
         paperRect.bottomRight() + QPointF(shWidth, shWidth));
  QRadialGradient cgrad(cshadow.topLeft(), shWidth, cshadow.topLeft());
  cgrad.setColorAt(0.0, QColor(0,0,0,255));
  cgrad.setColorAt(1.0, QColor(0,0,0,0));
  painter->fillRect(cshadow, QBrush(cgrad));

  painter->setClipRect(paperRect & option->exposedRect);
  painter->fillRect(paperRect, Qt::white);
  if (pagePicture.isNull())
      return;
  painter->drawImage(pageRect.topLeft(), pagePicture);

  // Effect: make anything drawn in the margins look washed out.
  QPainterPath path;
  path.addRect(paperRect);
  path.addRect(pageRect);
  painter->setPen(QPen(Qt::NoPen));
  painter->setBrush(QColor(255, 255, 255, 180));
  painter->drawPath(path);
}
}

class PrintWidget : public QGraphicsView
{
	Q_OBJECT
public:
	PrintWidget(QPrinter *printer, QWidget *parent = 0);
  ~PrintWidget();
	enum ViewMode {
		SinglePageView,
		FacingPagesView,
		AllPagesView
	};

	enum ZoomMode {
		CustomZoom,
		FitToWidth,
		FitInView
	};

  double getZoomFactor() const { return this->zoomFactor; };
  ZoomMode getZoomMode() const { return this->zoomMode; };
  int currentPage() const { return curPage; };
  void setPictures(QHash<int, QImage>*);

signals:
	void resized();
	void customContextMenuRequested(const QPoint&);
	void paintRequested(QPrinter*);
public slots:
	void zoomIn(double factor=1.2);
  void zoomOut(double factor=1.2);
  void setCurrentPage(int);
  void setVisible(bool) Q_DECL_OVERRIDE;

	void fitView();
  void fitToWidth();
  void setAllPagesViewMode();
  void setSinglePageViewMode();
  void setFacingPagesViewMode();

	void updateCurrentPage();
  int calcCurrentPage();
  void fit(bool doFitting=false);
  void updatePreview();
protected:
	void resizeEvent(QResizeEvent* e) Q_DECL_OVERRIDE {
		/*{
			const QSignalBlocker blocker(verticalScrollBar()); // Don't change page, QTBUG-14517
			QGraphicsView::resizeEvent(e);
		}*/
		QGraphicsView::resizeEvent(e);
		emit resized();
 	}

	void showEvent(QShowEvent* e) Q_DECL_OVERRIDE {
	  QGraphicsView::showEvent(e);
		emit resized();
	}
private:
  void generatePreview();
  void layoutPages();
  void populateScene();
  void setViewMode(ViewMode);
  void setZoomMode(ZoomMode);
  QGraphicsScene *scene;
  QPrinter *printer;
  QPreviewPaintEngine *previewEngine;
  QPdfPrintEngine *pdfEngine;

  int curPage;
	ViewMode viewMode;
	ZoomMode zoomMode;
	double zoomFactor;
	bool initialized, fitting;
	QList<QGraphicsItem *> pages;
  QHash<int, QImage> *pictures;
};
#endif