/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/layers/PLayersChild.h"
#include "BasicTiledThebesLayer.h"
#include "gfxImageSurface.h"
#include "sampler.h"
#include "gfxPlatform.h"

#ifdef GFX_TILEDLAYER_DEBUG_OVERLAY
#include "cairo.h"
#include <sstream>
using mozilla::layers::Layer;
static void DrawDebugOverlay(gfxImageSurface* imgSurf, int x, int y)
{
  gfxContext c(imgSurf);

  // Draw border
  c.NewPath();
  c.SetDeviceColor(gfxRGBA(0.0, 0.0, 0.0, 1.0));
  c.Rectangle(gfxRect(gfxPoint(0,0),imgSurf->GetSize()));
  c.Stroke();

  // Build tile description
  std::stringstream ss;
  ss << x << ", " << y;

  // Draw text using cairo toy text API
  cairo_t* cr = c.GetCairo();
  cairo_set_font_size(cr, 25);
  cairo_text_extents_t extents;
  cairo_text_extents(cr, ss.str().c_str(), &extents);

  int textWidth = extents.width + 6;

  c.NewPath();
  c.SetDeviceColor(gfxRGBA(0.0, 0.0, 0.0, 1.0));
  c.Rectangle(gfxRect(gfxPoint(2,2),gfxSize(textWidth, 30)));
  c.Fill();

  c.NewPath();
  c.SetDeviceColor(gfxRGBA(1.0, 0.0, 0.0, 1.0));
  c.Rectangle(gfxRect(gfxPoint(2,2),gfxSize(textWidth, 30)));
  c.Stroke();

  c.NewPath();
  cairo_move_to(cr, 4, 28);
  cairo_show_text(cr, ss.str().c_str());

}

#endif

namespace mozilla {
namespace layers {

bool
BasicTiledLayerBuffer::HasFormatChanged(BasicTiledThebesLayer* aThebesLayer) const
{
  return aThebesLayer->CanUseOpaqueSurface() != mLastPaintOpaque;
}


gfxASurface::gfxImageFormat
BasicTiledLayerBuffer::GetFormat() const
{
  if (mThebesLayer->CanUseOpaqueSurface()) {
    return gfxASurface::ImageFormatRGB16_565;
  } else {
    return gfxASurface::ImageFormatARGB32;
  }
}

void
BasicTiledLayerBuffer::PaintThebes(BasicTiledThebesLayer* aLayer,
                                   const nsIntRegion& aNewValidRegion,
                                   const nsIntRegion& aPaintRegion,
                                   LayerManager::DrawThebesLayerCallback aCallback,
                                   void* aCallbackData)
{
  mThebesLayer = aLayer;
  mCallback = aCallback;
  mCallbackData = aCallbackData;

#ifdef GFX_TILEDLAYER_PREF_WARNINGS
  long start = PR_IntervalNow();
#endif

  // If this region is empty XMost() - 1 will give us a negative value.
  NS_ASSERTION(!aPaintRegion.GetBounds().IsEmpty(), "Empty paint region\n");

  bool useSinglePaintBuffer = UseSinglePaintBuffer();
  if (useSinglePaintBuffer) {
    // Check if the paint only spans a single tile. If that's
    // the case there's no point in using a single paint buffer.
    nsIntRect paintBounds = aPaintRegion.GetBounds();
    useSinglePaintBuffer = GetTileStart(paintBounds.x) !=
                           GetTileStart(paintBounds.XMost() - 1) ||
                           GetTileStart(paintBounds.y) !=
                           GetTileStart(paintBounds.YMost() - 1);
  }

  if (useSinglePaintBuffer) {
    const nsIntRect bounds = aPaintRegion.GetBounds();
    {
      SAMPLE_LABEL("BasicTiledLayerBuffer", "PaintThebesSingleBufferAlloc");
      mSinglePaintBuffer = new gfxImageSurface(gfxIntSize(bounds.width, bounds.height), GetFormat(), !aLayer->CanUseOpaqueSurface());
      mSinglePaintBufferOffset = nsIntPoint(bounds.x, bounds.y);
    }
    nsRefPtr<gfxContext> ctxt = new gfxContext(mSinglePaintBuffer);
    ctxt->NewPath();
    ctxt->Translate(gfxPoint(-bounds.x, -bounds.y));
#ifdef GFX_TILEDLAYER_PREF_WARNINGS
    if (PR_IntervalNow() - start > 3) {
      printf_stderr("Slow alloc %i\n", PR_IntervalNow() - start);
    }
    start = PR_IntervalNow();
#endif
    SAMPLE_LABEL("BasicTiledLayerBuffer", "PaintThebesSingleBufferDraw");

    mCallback(mThebesLayer, ctxt, aPaintRegion, nsIntRegion(), mCallbackData);
  }

#ifdef GFX_TILEDLAYER_PREF_WARNINGS
  if (PR_IntervalNow() - start > 30) {
    const nsIntRect bounds = aPaintRegion.GetBounds();
    printf_stderr("Time to draw %i: %i, %i, %i, %i\n", PR_IntervalNow() - start, bounds.x, bounds.y, bounds.width, bounds.height);
    if (aPaintRegion.IsComplex()) {
      printf_stderr("Complex region\n");
      nsIntRegionRectIterator it(aPaintRegion);
      for (const nsIntRect* rect = it.Next(); rect != nullptr; rect = it.Next()) {
        printf_stderr(" rect %i, %i, %i, %i\n", rect->x, rect->y, rect->width, rect->height);
      }
    }
  }
  start = PR_IntervalNow();
#endif

  SAMPLE_LABEL("BasicTiledLayerBuffer", "PaintThebesUpdate");
  Update(aNewValidRegion, aPaintRegion);

#ifdef GFX_TILEDLAYER_PREF_WARNINGS
  if (PR_IntervalNow() - start > 10) {
    const nsIntRect bounds = aPaintRegion.GetBounds();
    printf_stderr("Time to tile %i: %i, %i, %i, %i\n", PR_IntervalNow() - start, bounds.x, bounds.y, bounds.width, bounds.height);
  }
#endif

  mLastPaintOpaque = mThebesLayer->CanUseOpaqueSurface();
  mThebesLayer = nullptr;
  mCallback = nullptr;
  mCallbackData = nullptr;
  mSinglePaintBuffer = nullptr;
}

BasicTiledLayerTile
BasicTiledLayerBuffer::ValidateTileInternal(BasicTiledLayerTile aTile,
                                            const nsIntPoint& aTileOrigin,
                                            const nsIntRect& aDirtyRect)
{
  if (aTile == GetPlaceholderTile() || aTile.mSurface->Format() != GetFormat()) {
    gfxImageSurface* tmpTile = new gfxImageSurface(gfxIntSize(GetTileLength(), GetTileLength()),
                                                   GetFormat(), !mThebesLayer->CanUseOpaqueSurface());
    aTile = BasicTiledLayerTile(tmpTile);
  }

  gfxRect drawRect(aDirtyRect.x - aTileOrigin.x, aDirtyRect.y - aTileOrigin.y,
                   aDirtyRect.width, aDirtyRect.height);

  // Use the gfxReusableSurfaceWrapper, which will reuse the surface
  // if the compositor no longer has a read lock, otherwise the surface
  // will be copied into a new writable surface.
  gfxImageSurface* writableSurface;
  aTile.mSurface = aTile.mSurface->GetWritable(&writableSurface);

  // Bug 742100, this gfxContext really should live on the stack.
  nsRefPtr<gfxContext> ctxt = new gfxContext(writableSurface);
  if (mSinglePaintBuffer) {
    ctxt->SetOperator(gfxContext::OPERATOR_SOURCE);
    ctxt->NewPath();
    ctxt->SetSource(mSinglePaintBuffer.get(),
                    gfxPoint(mSinglePaintBufferOffset.x - aDirtyRect.x + drawRect.x,
                             mSinglePaintBufferOffset.y - aDirtyRect.y + drawRect.y));
    ctxt->Rectangle(drawRect, true);
    ctxt->Fill();
  } else {
    ctxt->NewPath();
    ctxt->Translate(gfxPoint(-aTileOrigin.x, -aTileOrigin.y));
    nsIntPoint a = aTileOrigin;
    mCallback(mThebesLayer, ctxt, nsIntRegion(nsIntRect(a, nsIntSize(GetTileLength(), GetTileLength()))), nsIntRegion(), mCallbackData);
  }

#ifdef GFX_TILEDLAYER_DEBUG_OVERLAY
  DrawDebugOverlay(writableSurface, aTileOrigin.x, aTileOrigin.y);
#endif

  return aTile;
}

BasicTiledLayerTile
BasicTiledLayerBuffer::ValidateTile(BasicTiledLayerTile aTile,
                                    const nsIntPoint& aTileOrigin,
                                    const nsIntRegion& aDirtyRegion)
{

  SAMPLE_LABEL("BasicTiledLayerBuffer", "ValidateTile");

#ifdef GFX_TILEDLAYER_PREF_WARNINGS
  if (aDirtyRegion.IsComplex()) {
    printf_stderr("Complex region\n");
  }
#endif

  nsIntRegionRectIterator it(aDirtyRegion);
  for (const nsIntRect* rect = it.Next(); rect != nullptr; rect = it.Next()) {
#ifdef GFX_TILEDLAYER_PREF_WARNINGS
    printf_stderr(" break into subrect %i, %i, %i, %i\n", rect->x, rect->y, rect->width, rect->height);
#endif
    aTile = ValidateTileInternal(aTile, aTileOrigin, *rect);
  }

  return aTile;
}

void
BasicTiledThebesLayer::FillSpecificAttributes(SpecificLayerAttributes& aAttrs)
{
  aAttrs = ThebesLayerAttributes(GetValidRegion());
}

void
BasicTiledThebesLayer::PaintThebes(gfxContext* aContext,
                                   Layer* aMaskLayer,
                                   LayerManager::DrawThebesLayerCallback aCallback,
                                   void* aCallbackData,
                                   ReadbackProcessor* aReadback)
{
  if (!aCallback) {
    BasicManager()->SetTransactionIncomplete();
    return;
  }

  if (!HasShadow()) {
    NS_ASSERTION(false, "Shadow requested for painting\n");
    return;
  }

  if (mTiledBuffer.HasFormatChanged(this)) {
    mValidRegion = nsIntRegion();
  }

  nsIntRegion regionToPaint = mVisibleRegion;
  regionToPaint.Sub(regionToPaint, mValidRegion);
  if (regionToPaint.IsEmpty())
    return;

  gfxSize resolution(1, 1);
  for (ContainerLayer* parent = GetParent(); parent; parent = parent->GetParent()) {
    const FrameMetrics& metrics = parent->GetFrameMetrics();
    resolution.width *= metrics.mResolution.width;
    resolution.height *= metrics.mResolution.height;
  }

  // Calculate the scroll offset since the last transaction. Progressive tile
  // painting is only used when scrolling.
  gfx::Point scrollOffset(0, 0);
  Layer* primaryScrollable = BasicManager()->GetPrimaryScrollableLayer();
  if (primaryScrollable) {
    const FrameMetrics& metrics = primaryScrollable->AsContainerLayer()->GetFrameMetrics();
    scrollOffset = metrics.mScrollOffset;
  }
  int32_t scrollDiffX = scrollOffset.x - mLastScrollOffset.x;
  int32_t scrollDiffY = scrollOffset.y - mLastScrollOffset.y;

  // Only draw progressively when we're panning and the resolution is unchanged.
  if (gfxPlatform::UseProgressiveTilePainting() &&
      mTiledBuffer.GetResolution() == resolution &&
      (scrollDiffX != 0 || scrollDiffY != 0)) {
    // Paint tiles that have no content before tiles that only have stale content.
    nsIntRegion staleRegion = mTiledBuffer.GetValidRegion();
    staleRegion.And(staleRegion, regionToPaint);
    bool hasNewContent = !staleRegion.Contains(regionToPaint);
    if (!staleRegion.IsEmpty() && hasNewContent) {
      regionToPaint.Sub(regionToPaint, staleRegion);
    }

    // Find out the current view transform to determine which tiles to draw
    // first, and see if we should just abort this paint. Aborting is usually
    // caused by there being an incoming, more relevant paint.
    gfx::Rect viewport;
    float scaleX, scaleY;
    if (BasicManager()->ProgressiveUpdateCallback(hasNewContent, viewport, scaleX, scaleY)) {
      return;
    }

    // The following code decides what order to draw tiles in, based on the
    // current scroll direction of the primary scrollable layer.
    // XXX While this code is of a reasonable size currently, it is likely
    //     we'll want to add more comprehensive methods of deciding what
    //     tiles to draw. This is a good candidate for splitting out into a
    //     separate function.

    // First, decide whether to iterate on the region from the beginning or end
    // of the rect list. This relies on the specific behaviour of nsRegion when
    // subtracting rects. If we're moving more in the X direction, we draw
    // tiles by column, otherwise by row.
    nsIntRegionRectIterator it(regionToPaint);
    const nsIntRect* rect;
    if ((NS_ABS(scrollDiffY) > NS_ABS(scrollDiffX) && scrollDiffY >= 0)) {
      rect = it.Next();
    } else {
      const nsIntRect* lastRect;
      while ((lastRect = it.Next())) {
        rect = lastRect;
      }
    }

    // Second, decide what direction to start drawing rects from by checking
    // the scroll offset difference of the primary scrollable layer. If we're
    // scrolling to the right, make sure to start from the left, downwards
    // start from the top, etc.
    int paintTileStartX, paintTileStartY;
    if (scrollOffset.x >= mLastScrollOffset.x) {
      paintTileStartX = mTiledBuffer.RoundDownToTileEdge(rect->x);
    } else {
      paintTileStartX = mTiledBuffer.RoundDownToTileEdge(rect->XMost() - 1);
    }

    if (scrollOffset.y >= mLastScrollOffset.y) {
      paintTileStartY = mTiledBuffer.RoundDownToTileEdge(rect->y);
    } else {
      paintTileStartY = mTiledBuffer.RoundDownToTileEdge(rect->YMost() - 1);
    }

    nsIntRegion maxPaint(
      nsIntRect(paintTileStartX, paintTileStartY,
                mTiledBuffer.GetTileLength(), mTiledBuffer.GetTileLength()));

    if (!maxPaint.Contains(regionToPaint)) {
      // The region needed to paint is larger then our progressive chunk size
      // therefore update what we want to paint and ask for a new paint transaction.
      regionToPaint.And(regionToPaint, maxPaint);
      BasicManager()->SetRepeatTransaction();

      // Make sure that tiles that fall outside of the visible region are discarded.
      mValidRegion.And(mValidRegion, mVisibleRegion);
    } else {
      // The transaction is completed, store the last scroll offset.
      mLastScrollOffset = scrollOffset;
    }

    // Keep track of what we're about to refresh.
    mValidRegion.Or(mValidRegion, regionToPaint);
  } else {
    mTiledBuffer.SetResolution(resolution);
    mValidRegion = mVisibleRegion;
  }

  mTiledBuffer.PaintThebes(this, mValidRegion, regionToPaint, aCallback, aCallbackData);

  mTiledBuffer.ReadLock();
  if (aMaskLayer) {
    static_cast<BasicImplData*>(aMaskLayer->ImplData())
      ->Paint(aContext, nullptr);
  }

  // Create a heap copy owned and released by the compositor. This is needed
  // since we're sending this over an async message and content needs to be
  // be able to modify the tiled buffer in the next transaction.
  // TODO: Remove me once Bug 747811 lands.
  BasicTiledLayerBuffer *heapCopy = new BasicTiledLayerBuffer(mTiledBuffer);

  BasicManager()->PaintedTiledLayerBuffer(BasicManager()->Hold(this), heapCopy);
}

} // mozilla
} // layers