#include "PrintWidget.h"

PrintWidget::PrintWidget(Renderer *backend, QWidget *parent) : 
  QGraphicsView(parent), scene(0), curPage(1), viewMode(SinglePageView), 
  zoomMode(FitInView), zoomFactor(1), initialized(false), fitting(true), BACKEND(backend) {

  this->setMouseTracking(true);
  QList<QWidget*> children = this->findChildren<QWidget*>("",Qt::FindChildrenRecursively);
  for(int i=0; i<children.length(); i++){
    children[i]->setContextMenuPolicy(Qt::CustomContextMenu);
    connect(children[i], SIGNAL(customContextMenuRequested(const QPoint&)), this, SIGNAL(customContextMenuRequested(const QPoint&)) );
  }
  this->setInteractive(false);
  this->setDragMode(QGraphicsView::ScrollHandDrag);
  this->setViewportUpdateMode(QGraphicsView::SmartViewportUpdate);
  this->setFocusPolicy(Qt::NoFocus);
  QObject::connect(this->verticalScrollBar(), SIGNAL(valueChanged(int)),
                   this, SLOT(updateCurrentPage()));
  QObject::connect(this, SIGNAL(resized()), this, SLOT(fit()));

  scene = new QGraphicsScene(this);
  scene->setBackgroundBrush(Qt::gray);
  this->setScene(scene);

  /*QVBoxLayout *layout = new QVBoxLayout;
  setLayout(layout);
  layout->setContentsMargins(0, 0, 0, 0);
  layout->addWidget(this);*/
}

PrintWidget::~PrintWidget() {
  for (int i = 0; i < pages.size(); i++){
    scene->removeItem(pages.at(i));
  }
  qDeleteAll(pages);
  pages.clear(); 
  scene->deleteLater();
}

//Public Slots

void PrintWidget::fitView() {
  setZoomMode(FitInView);
  setCurrentPage(publicPageNum); //Make sure we stay on the same page
}

void PrintWidget::fitToWidth() {
  setZoomMode(FitToWidth);
  setCurrentPage(publicPageNum); //Make sure we stay on the same page
}

void PrintWidget::setZoomMode(ZoomMode mode) {
  zoomMode = mode;
  fitting = true;
  fit(true);
}

void PrintWidget::setAllPagesViewMode() {
  setViewMode(AllPagesView);
}

void PrintWidget::setSinglePageViewMode() {
  setViewMode(SinglePageView);
}

void PrintWidget::setFacingPagesViewMode() {
  setViewMode(FacingPagesView);
}

void PrintWidget::setViewMode(ViewMode mode) {
  viewMode = mode;
  layoutPages();
  if (viewMode == AllPagesView) {
    this->fitInView(scene->itemsBoundingRect(), Qt::KeepAspectRatio);
    fitting = false;
    zoomMode = CustomZoom;
    zoomFactor = this->transform().m11() * (150.0 / logicalDpiY());
  } else {
    fitting = true;
    fit();
  }
}

void PrintWidget::zoomIn(double factor) {
  fitting = false;
  zoomMode = CustomZoom;
  zoomFactor *= factor;
  this->scale(factor, factor);
}

void PrintWidget::zoomOut(double factor) {
  fitting = false;
  zoomMode = CustomZoom;
  zoomFactor *= factor;
  this->scale(1/factor, 1/factor);
}

void PrintWidget::updatePreview() {
  initialized = true;
  generatePreview();
  this->updateGeometry();
}

void PrintWidget::setVisible(bool visible) {
  if(visible and !initialized)
    updatePreview();
  QGraphicsView::setVisible(visible);
}

void PrintWidget::setCurrentPage(int pageNumber) {
  if(pageNumber < 0 || pageNumber > (pages.count()+1) ){ return; }
  publicPageNum = pageNumber; //publicly requested page number (+/- 1 from actual page range)
  emit currentPageChanged();
  if(pageNumber < 1 || pageNumber > pages.count())
    return;
  int lastPage = curPage;
  curPage = pageNumber;

  if (lastPage != curPage && lastPage > 0 && lastPage <= pages.count()) {
    if (zoomMode != FitInView) {
      QScrollBar *hsc = this->horizontalScrollBar();
      QScrollBar *vsc = this->verticalScrollBar();
      QPointF pt = this->transform().map(pages.at(curPage-1)->pos());
      vsc->setValue(int(pt.y()) - 10);
      hsc->setValue(int(pt.x()) - 10);
    } else {
      this->centerOn(pages.at(curPage-1));
    }
  }
}

void PrintWidget::highlightText(TextData *text) {
  //Creates a rectangle around the text if the text has not already been highlighted
  if(!text->highlighted() && !text->loc().isNull()) {
    int degrees = BACKEND->rotatedDegrees();
    //Shows the text's location on a non-rotated page
    QRectF rect = text->loc();
    //Rotates the rectangle by the page's center and gets the right calculation for text's new location
    if(degrees != 0) {
      QSize center = BACKEND->imageHash(text->page()-1).size()/2;

      if(degrees == 90 or degrees == 270)
        center.transpose();

      double cx = center.width(), cy = center.height();
      rect.adjust(-cx, -cy, -cx, -cy);
      QMatrix matrix;
      matrix.rotate(BACKEND->rotatedDegrees());
      rect = matrix.mapRect(rect);
      if(BACKEND->rotatedDegrees() == 180)
        rect.adjust(cx, cy, cx, cy);
      else
        rect.adjust(cy, cx, cy, cx);
    }
    //Moves the rectangle onto the right page
    double pageHeight = 0;
    for(int i = 0; i < text->page() - 1; i++)
      pageHeight += pages.at(i)->boundingRect().height();

    rect.moveTop(rect.y() + pageHeight);
    //Transparent yellow for the highlight box
    QBrush highlightFill(QColor(255, 255, 177, 100));
    QPen highlightOutline(QColor(255, 255, 100, 125));
    scene->addRect(rect, highlightOutline, highlightFill);
    text->highlighted(true);
  }
  goToPosition(text->page(), text->loc().x(), text->loc().y());
}

//Private functions

void PrintWidget::generatePreview() {
  populateScene(); // i.e. setPreviewPrintedPictures() e.l.
  layoutPages();
  curPage = qBound(1, curPage, pages.count());
  publicPageNum = curPage;
  emit currentPageChanged();
  if (fitting){ fit(); }
}

void PrintWidget::layoutPages() {
  int numPages = pages.count();
  if (numPages < 1)
    return;

  int numPagePlaces = numPages;
  int cols = 1; // singleMode and default
  QSize pageSize = BACKEND->imageHash(curPage-1).size();
  if (viewMode == AllPagesView) {
    cols = pageSize.width() > pageSize.height() ? qFloor(qSqrt(numPages)) : qCeil(qSqrt(numPages));
    cols += cols % 2;  // Nicer with an even number of cols
  } else if (viewMode == FacingPagesView) {
    cols = 2;
    numPagePlaces += 1;
  }
  int rows = qCeil(double(numPagePlaces) / cols);

  int pageNum = 0; 
  QList<double> rowMaxList;
  for (int i = 0; i < rows && pageNum < numPages; i++) {
    double rowMax = 0;
    for (int j = 0; j < cols && pageNum < numPages; j++) {
      double itemWidth = 0, itemHeight = 0;
      double pageHeight = pages.at(pageNum)->boundingRect().height();

      for(int k = cols * (pageNum / cols); k < pageNum; k++)
        itemWidth += pages.at(k)->boundingRect().width();

      foreach(double size, rowMaxList)
        itemHeight += size;  

      pages.at(pageNum)->setPos(QPointF(itemWidth, itemHeight));
      pageNum++;
      rowMax = qMax(rowMax, pageHeight);
    }
    rowMaxList.push_back(rowMax);
  }
  scene->setSceneRect(scene->itemsBoundingRect());
  //qDebug() << "Finished Page Layout";
}

void PrintWidget::populateScene()
{
  for (int i = 0; i < pages.size(); i++){
    scene->removeItem(pages.at(i));
  }
  for(int i = 0; i < links.size(); i++) {
    if(links[i].size() > 0) {
      qDeleteAll(links[i]);
      links[i].clear();
    }
  }
  links.clear();
  qDeleteAll(pages);
  pages.clear();
  int numPages = BACKEND->numPages();
  if(BACKEND->hashSize() < numPages){ return; } //nothing to show yet

  for (int i = 0; i < numPages; i++) {
    QImage pagePicture = BACKEND->imageHash(i);
    QSize paperSize = pagePicture.size();
    QList<QGraphicsItem*> linkLocations;

    if(pagePicture.isNull()) {
      qDebug() << "NULL IMAGE ON PAGE " << i;
      continue;
    }

    PageItem* item = new PageItem(i+1, pagePicture, paperSize);
    scene->addItem(item);
    pages.append(item);

    if(BACKEND->supportsExtraFeatures()) {
      for(int k = 0; k < BACKEND->linkSize(i); k++) {
        LinkItem *lItem = new LinkItem(item, BACKEND->linkList(i, k));
        lItem->setOpacity(0.1);
        linkLocations.append(lItem);
      }
      links.insert(i, linkLocations);
    }
  }
}

//Private Slots
void PrintWidget::updateCurrentPage() {
  if (viewMode == AllPagesView)
    return;

  int newPage = calcCurrentPage();
  if (newPage != curPage) {
    curPage = newPage;
    publicPageNum = curPage;
    emit currentPageChanged();
  }
}

int PrintWidget::calcCurrentPage() {
  int maxArea = 0;
  int newPage = curPage;
  QRect viewRect = this->viewport()->rect();
  QList<QGraphicsItem*> items = this->items(viewRect);
  for (int i=0; i<items.size(); ++i) {
    PageItem* pg = static_cast<PageItem*>(items.at(i));
    QRect overlap = this->mapFromScene(pg->sceneBoundingRect()).boundingRect() & viewRect;
    int area = overlap.width() * overlap.height();
    if (area > maxArea) {
      maxArea = area;
      newPage = pg->pageNumber();
    } else if (area == maxArea && pg->pageNumber() < newPage) {
      newPage = pg->pageNumber();
    }
  }
  return newPage;
}

void PrintWidget::fit(bool doFitting) {
  if (curPage < 1 || curPage > pages.count())
    return;
  if (!doFitting && !fitting)
    return;

  if (doFitting && fitting) {
    QRect viewRect = this->viewport()->rect();
    if (zoomMode == FitInView) {
      QList<QGraphicsItem*> containedItems = this->items(viewRect, Qt::ContainsItemBoundingRect);
      foreach(QGraphicsItem* item, containedItems) {
        PageItem* pg = static_cast<PageItem*>(item);
        if (pg->pageNumber() == curPage)
          return;
      }
    }

    int newPage = calcCurrentPage();
    if (newPage != curPage)
      curPage = newPage;
  }

  QRectF target = pages.at(curPage-1)->sceneBoundingRect();
  if (viewMode == FacingPagesView) {
    if (curPage % 2)
      target.setLeft(target.left() - target.width());
    else
      target.setRight(target.right() + target.width());
  } else if (viewMode == AllPagesView) {
    target = scene->itemsBoundingRect();
  }

  if (zoomMode == FitToWidth) {
    QTransform t;
    qreal scale = this->viewport()->width() / target.width();
    t.scale(scale, scale);
    this->setTransform(t);
    if (doFitting && fitting) {
      QRectF viewSceneRect = this->viewportTransform().mapRect(this->viewport()->rect());
      viewSceneRect.moveTop(target.top());
      this->ensureVisible(viewSceneRect); // Nah...
    }
  } else {
    this->fitInView(target, Qt::KeepAspectRatio);
    if (zoomMode == FitInView) {
      int step = qRound(this->matrix().mapRect(target).height());
      this->verticalScrollBar()->setSingleStep(step);
      this->verticalScrollBar()->setPageStep(step);
    }
  }

  zoomFactor = this->transform().m11() * (150.0 / this->logicalDpiY());
}

void PrintWidget::goToPosition(int pagenum, float x, float y) {
  setCurrentPage(pagenum);
  
  QScrollBar *hsc = this->horizontalScrollBar();
  QScrollBar *vsc = this->verticalScrollBar();
  QPointF pt = this->transform().map(pages.at(pagenum-1)->pos());
  int secondPagenum = pagenum < pages.size() ? pagenum : pagenum-2;
  QPointF pt2 = this->transform().map(pages.at(secondPagenum)->pos());
  double realHeight = pages.at(pagenum-1)->boundingRect().height();
  double virtualHeight = qAbs(pt2.y() - pt.y());

  int yConv = int(pt.y() + y*(virtualHeight/realHeight)) - 30;
  int xConv = int(pt.x() + x*(virtualHeight/realHeight)) - 30;

  if(yConv > vsc->maximum())
    vsc->triggerAction(QAbstractSlider::SliderToMaximum);
  else if(y != 0)
    vsc->setValue(yConv);

  if(x != 0)
    hsc->setValue(xConv);
}