/* 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 "RenderCompositorSWGL.h"

#include "mozilla/gfx/Logging.h"
#include "mozilla/widget/CompositorWidget.h"

#ifdef MOZ_WIDGET_GTK
#  include "mozilla/WidgetUtilsGtk.h"
#endif

namespace mozilla {
using namespace gfx;

namespace wr {

extern LazyLogModule gRenderThreadLog;
#define LOG(...) MOZ_LOG(gRenderThreadLog, LogLevel::Debug, (__VA_ARGS__))

/* static */
UniquePtr<RenderCompositor> RenderCompositorSWGL::Create(
    const RefPtr<widget::CompositorWidget>& aWidget, nsACString& aError) {
  void* ctx = wr_swgl_create_context();
  if (!ctx) {
    gfxCriticalNote << "Failed SWGL context creation for WebRender";
    return nullptr;
  }
  return MakeUnique<RenderCompositorSWGL>(aWidget, ctx);
}

RenderCompositorSWGL::RenderCompositorSWGL(
    const RefPtr<widget::CompositorWidget>& aWidget, void* aContext)
    : RenderCompositor(aWidget), mContext(aContext) {
  MOZ_ASSERT(mContext);
  LOG("RenderCompositorSWGL::RenderCompositorSWGL()");
}

RenderCompositorSWGL::~RenderCompositorSWGL() {
  LOG("RenderCompositorSWGL::~RenderCompositorSWGL()");

  wr_swgl_destroy_context(mContext);
}

void RenderCompositorSWGL::ClearMappedBuffer() {
  mMappedData = nullptr;
  mMappedStride = 0;
  mDT = nullptr;
}

bool RenderCompositorSWGL::MakeCurrent() {
  wr_swgl_make_current(mContext);
  return true;
}

bool RenderCompositorSWGL::BeginFrame() {
  mRenderWidgetSize = Some(mWidget->GetClientSize());
#ifdef MOZ_WIDGET_GTK
  if (mLastRenderWidgetSize != mRenderWidgetSize.value()) {
    mLastRenderWidgetSize = mRenderWidgetSize.value();
    mRequestFullRender = true;
  }
#endif
  // Set up a temporary region representing the entire window surface in case a
  // dirty region is not supplied.
  ClearMappedBuffer();
  mDirtyRegion = LayoutDeviceIntRect(LayoutDeviceIntPoint(), GetBufferSize());
  wr_swgl_make_current(mContext);
  return true;
}

bool RenderCompositorSWGL::AllocateMappedBuffer(
    const wr::DeviceIntRect* aOpaqueRects, size_t aNumOpaqueRects) {
  // Request a new draw target to use from the widget...
  MOZ_ASSERT(!mDT);
  mDT = mWidget->StartRemoteDrawingInRegion(mDirtyRegion);
  if (!mDT) {
    gfxCriticalNoteOnce
        << "RenderCompositorSWGL failed mapping default framebuffer, no dt";
    return false;
  }
  // Attempt to lock the underlying buffer directly from the draw target.
  // Verify that the size at least matches what the widget claims and that
  // the format is BGRA8 as SWGL requires.
  uint8_t* data = nullptr;
  gfx::IntSize size;
  int32_t stride = 0;
  gfx::SurfaceFormat format = gfx::SurfaceFormat::UNKNOWN;
  if (!mSurface && mDT->LockBits(&data, &size, &stride, &format) &&
      (format != gfx::SurfaceFormat::B8G8R8A8 &&
       format != gfx::SurfaceFormat::B8G8R8X8)) {
    // We tried to lock the DT and it succeeded, but the size or format
    // of the data is not compatible, so just release it and fall back below...
    mDT->ReleaseBits(data);
    data = nullptr;
  }
  LayoutDeviceIntRect bounds = mDirtyRegion.GetBounds();
  // If locking succeeded above, just use that.
  if (data) {
    mMappedData = data;
    mMappedStride = stride;
    // Disambiguate whether the widget's draw target has its origin at zero or
    // if it is offset to the dirty region origin. The DT might either enclose
    // only the region itself, the region including the origin, or the entire
    // widget. Thus, if the DT doesn't only enclose the region, we assume it
    // contains the origin.
    if (size != bounds.Size().ToUnknownSize()) {
      // Update the bounds to include zero if the origin is at zero.
      bounds.ExpandToEnclose(LayoutDeviceIntPoint(0, 0));
    }
    // Sometimes we end up racing on the widget size, and it can shrink between
    // BeginFrame and StartCompositing. We calculated our dirty region based on
    // the previous widget size, so we need to clamp the bounds here to ensure
    // we remain within the buffer.
    bounds.IntersectRect(
        bounds,
        LayoutDeviceIntRect(bounds.TopLeft(),
                            LayoutDeviceIntSize(size.width, size.height)));
  } else {
    // If we couldn't lock the DT above, then allocate a data surface and map
    // that for usage with SWGL.
    size = bounds.Size().ToUnknownSize();
    if (!mSurface || mSurface->GetSize() != size) {
      mSurface = gfx::Factory::CreateDataSourceSurface(
          size, gfx::SurfaceFormat::B8G8R8A8);
    }
    gfx::DataSourceSurface::MappedSurface map = {nullptr, 0};
    if (!mSurface || !mSurface->Map(gfx::DataSourceSurface::READ_WRITE, &map)) {
      // We failed mapping the data surface, so need to cancel the frame.
      mWidget->EndRemoteDrawingInRegion(mDT, mDirtyRegion);
      ClearMappedBuffer();
      gfxCriticalNoteOnce
          << "RenderCompositorSWGL failed mapping default framebuffer, no surf";
      return false;
    }
    mMappedData = map.mData;
    mMappedStride = map.mStride;
  }
  MOZ_ASSERT(mMappedData != nullptr && mMappedStride > 0);
  wr_swgl_init_default_framebuffer(mContext, bounds.x, bounds.y, bounds.width,
                                   bounds.height, mMappedStride, mMappedData);

  LayoutDeviceIntRegion opaque;
  for (size_t i = 0; i < aNumOpaqueRects; i++) {
    const auto& rect = aOpaqueRects[i];
    opaque.OrWith(LayoutDeviceIntRect(rect.min.x, rect.min.y, rect.width(),
                                      rect.height()));
  }

  LayoutDeviceIntRegion clear = mWidget->GetTransparentRegion();
  clear.AndWith(mDirtyRegion);
  clear.SubOut(opaque);
  for (auto iter = clear.RectIter(); !iter.Done(); iter.Next()) {
    const auto& rect = iter.Get();
    wr_swgl_clear_color_rect(mContext, 0, rect.x, rect.y, rect.width,
                             rect.height, 0, 0, 0, 0);
  }

  return true;
}

void RenderCompositorSWGL::StartCompositing(
    wr::ColorF aClearColor, const wr::DeviceIntRect* aDirtyRects,
    size_t aNumDirtyRects, const wr::DeviceIntRect* aOpaqueRects,
    size_t aNumOpaqueRects) {
  if (mDT) {
    // Cancel any existing buffers that might accidentally be left from updates
    CommitMappedBuffer(false);
    // Reset the region to the widget bounds
    mDirtyRegion = LayoutDeviceIntRect(LayoutDeviceIntPoint(), GetBufferSize());
  }
  if (aNumDirtyRects) {
    // Install the dirty rects into the bounds of the existing region
    auto bounds = mDirtyRegion.GetBounds();
    mDirtyRegion.SetEmpty();
    for (size_t i = 0; i < aNumDirtyRects; i++) {
      const auto& rect = aDirtyRects[i];
      mDirtyRegion.OrWith(LayoutDeviceIntRect(rect.min.x, rect.min.y,
                                              rect.width(), rect.height()));
    }
    // Ensure the region lies within the widget bounds
    mDirtyRegion.AndWith(bounds);
  }
  // Now that the dirty rects have been supplied and the composition region
  // is known, allocate and install a framebuffer encompassing the composition
  // region.
  if (mDirtyRegion.IsEmpty() ||
      !AllocateMappedBuffer(aOpaqueRects, aNumOpaqueRects)) {
    // If allocation of the mapped default framebuffer failed, then just install
    // a temporary framebuffer (with a minimum size of 2x2) so compositing can
    // still proceed.
    auto bounds = mDirtyRegion.GetBounds();
    bounds.width = std::max(bounds.width, 2);
    bounds.height = std::max(bounds.height, 2);
    wr_swgl_init_default_framebuffer(mContext, bounds.x, bounds.y, bounds.width,
                                     bounds.height, 0, nullptr);
  }
}

void RenderCompositorSWGL::CommitMappedBuffer(bool aDirty) {
  if (!mDT) {
    mDirtyRegion.SetEmpty();
    return;
  }
  // Force any delayed clears to resolve.
  if (aDirty) {
    wr_swgl_resolve_framebuffer(mContext, 0);
  }
  // Clear out the old framebuffer in case something tries to access it after
  // the frame.
  wr_swgl_init_default_framebuffer(mContext, 0, 0, 0, 0, 0, nullptr);
  // If we have a draw target at this point, mapping must have succeeded.
  MOZ_ASSERT(mMappedData != nullptr);
  if (mSurface) {
    // If we're using a data surface, unmap it and draw it to the DT if there
    // are any supplied dirty rects.
    mSurface->Unmap();
    if (aDirty) {
      // The temporary source surface is always a partial region of the widget
      // that is offset from the origin to the actual bounds of the dirty
      // region. The destination DT may also be an offset partial region, but we
      // must check to see if its size matches the region bounds to verify this.
      LayoutDeviceIntRect bounds = mDirtyRegion.GetBounds();
      gfx::IntPoint srcOffset = bounds.TopLeft().ToUnknownPoint();
      gfx::IntPoint dstOffset = mDT->GetSize() == bounds.Size().ToUnknownSize()
                                    ? srcOffset
                                    : gfx::IntPoint(0, 0);
      for (auto iter = mDirtyRegion.RectIter(); !iter.Done(); iter.Next()) {
        gfx::IntRect dirtyRect = iter.Get().ToUnknownRect();
        mDT->CopySurface(mSurface, dirtyRect - srcOffset,
                         dirtyRect.TopLeft() - dstOffset);
      }
    }
  } else {
    // Otherwise, we had locked the DT directly. Just release the data.
    mDT->ReleaseBits(mMappedData);
  }
  mDT->Flush();

  // Done with the DT. Hand it back to the widget and clear out any trace of it.
  mWidget->EndRemoteDrawingInRegion(mDT, mDirtyRegion);
  mDirtyRegion.SetEmpty();
  ClearMappedBuffer();
}

void RenderCompositorSWGL::CancelFrame() {
  CommitMappedBuffer(false);
  mRenderWidgetSize = Nothing();
}

RenderedFrameId RenderCompositorSWGL::EndFrame(
    const nsTArray<DeviceIntRect>& aDirtyRects) {
  // Dirty rects have already been set inside StartCompositing. We need to keep
  // those dirty rects exactly the same here so we supply the same exact region
  // to EndRemoteDrawingInRegion as for StartRemoteDrawingInRegion.
  RenderedFrameId frameId = GetNextRenderFrameId();
  CommitMappedBuffer();
  mRenderWidgetSize = Nothing();
  return frameId;
}

bool RenderCompositorSWGL::RequestFullRender() {
#if defined(MOZ_WIDGET_ANDROID)
  // XXX Add partial present support.
  return true;
#elif defined(MOZ_WIDGET_GTK)
  // We're requested to do full render after Resume() on Wayland.
  if (mRequestFullRender) {
    mRequestFullRender = false;
    return true;
  }
  return false;
#else
  return false;
#endif
}

void RenderCompositorSWGL::Pause() {}

bool RenderCompositorSWGL::Resume() {
#ifdef MOZ_WIDGET_GTK
  mRequestFullRender = true;
#endif
  return true;
}

LayoutDeviceIntSize RenderCompositorSWGL::GetBufferSize() {
  // If we're between BeginFrame() and EndFrame()/CancelFrame() calls
  // return recent rendering size instead of actual underlying widget
  // size. It prevents possible rendering artifacts if widget size was changed.
  return mRenderWidgetSize ? mRenderWidgetSize.value()
                           : mWidget->GetClientSize();
}

void RenderCompositorSWGL::GetCompositorCapabilities(
    CompositorCapabilities* aCaps) {
  // Always support a single update rect for SwCompositor
  aCaps->max_update_rects = 1;

  // On uncomposited desktops such as X11 without compositor or Window 7 with
  // Aero disabled we need to force a full redraw when the window contents may
  // be damaged.
#ifdef MOZ_WIDGET_GTK
  aCaps->redraw_on_invalidation = widget::GdkIsX11Display();
#else
  aCaps->redraw_on_invalidation = true;
#endif
}

}  // namespace wr
}  // namespace mozilla