// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "gpu/ipc/service/image_transport_surface_overlay_mac.h"

#include <dawn/native/MetalBackend.h>
#include <dawn/webgpu_cpp.h>

#include <memory>
#include <sstream>
#include <utility>
#include <variant>

#include "base/command_line.h"
#include "base/functional/bind.h"
#include "base/functional/callback_helpers.h"
#include "base/metrics/histogram_macros.h"
#include "base/rand_util.h"
#include "base/time/time.h"
#include "base/trace_event/trace_event.h"
#include "components/viz/common/features.h"
#include "gpu/command_buffer/common/swap_buffers_complete_params.h"
#include "gpu/ipc/service/gpu_channel_manager.h"
#include "gpu/ipc/service/gpu_channel_manager_delegate.h"
#include "ui/accelerated_widget_mac/ca_layer_tree_coordinator.h"
#include "ui/accelerated_widget_mac/ca_renderer_layer_tree.h"
#include "ui/gfx/geometry/rect_conversions.h"
#include "ui/gfx/gpu_fence.h"
#include "ui/gfx/overlay_plane_data.h"
#include "ui/gl/ca_renderer_layer_params.h"

#if BUILDFLAG(IS_IOS) && !BUILDFLAG(IS_IOS_TVOS)
#include "gpu/ipc/common/ios/be_layer_hierarchy_transport.h"
#endif

#if BUILDFLAG(SKIA_USE_DAWN)
#include "gpu/command_buffer/service/dawn_context_provider.h"
#endif

#if BUILDFLAG(SKIA_USE_METAL)
#include "gpu/command_buffer/service/metal_context_provider.h"
#endif

// From ANGLE's EGL/eglext_angle.h. This should be included instead of being
// redefined here.
#ifndef EGL_ANGLE_device_metal
#define EGL_ANGLE_device_metal 1
#define EGL_METAL_DEVICE_ANGLE 0x34A6
#endif /* EGL_ANGLE_device_metal */

namespace gpu {

namespace {
constexpr base::TimeDelta kHistogramMinTime = base::Microseconds(5);
constexpr base::TimeDelta kHistogramMaxTime = base::Milliseconds(16);
constexpr int kHistogramTimeBuckets = 50;

// Control use of AVFoundation to draw video content.
BASE_FEATURE(kAVFoundationOverlays,
             "avfoundation-overlays",
             base::FEATURE_ENABLED_BY_DEFAULT);

#if BUILDFLAG(IS_MAC)

// Record the delay from the system CVDisplayLink or CADisplaylink source to
// CrGpuMain OnVSyncPresentation().
void RecordVSyncCallbackDelay(base::TimeDelta delay) {
  UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES(
      "GPU.Presentation.VSyncCallbackDelay", delay,
      /*min=*/base::Microseconds(10),
      /*max=*/base::Milliseconds(33), /*bucket_count=*/50);
}
#endif  // BUILDFLAG(IS_MAC)

id<MTLDevice> GetMTLDevice(scoped_refptr<SharedContextState> context_state) {
#if BUILDFLAG(SKIA_USE_DAWN)
  if (context_state->IsGraphiteDawnMetal()) {
    CHECK(context_state->dawn_context_provider());
    return dawn::native::metal::GetMTLDevice(
        context_state->dawn_context_provider()->GetDevice().Get());
  }
#endif
#if BUILDFLAG(SKIA_USE_METAL)
  if (context_state->IsGraphiteMetal()) {
    CHECK(context_state->metal_context_provider());
    return context_state->metal_context_provider()->GetMTLDevice();
  }
#endif
  if (context_state->GrContextIsGL()) {
    EGLAttrib angle_device_attrib = 0;
    if (eglQueryDisplayAttribEXT(context_state->display()->GetDisplay(),
                                 EGL_DEVICE_EXT, &angle_device_attrib)) {
      EGLDeviceEXT angle_device =
          reinterpret_cast<EGLDeviceEXT>(angle_device_attrib);
      EGLAttrib metal_device_attrib = 0;
      if (eglQueryDeviceAttribEXT(angle_device, EGL_METAL_DEVICE_ANGLE,
                                  &metal_device_attrib)) {
        return (__bridge id)(void*)metal_device_attrib;
      }
    }
  }
  return nil;
}

}  // namespace

ImageTransportSurfaceOverlayMacEGL::ImageTransportSurfaceOverlayMacEGL(
    scoped_refptr<SharedContextState> context_state,
    SurfaceHandle surface_handle)
    : weak_ptr_factory_(this) {
  static bool av_disabled_at_command_line =
      !base::FeatureList::IsEnabled(kAVFoundationOverlays);

  auto buffer_presented_callback =
      base::BindRepeating(&ImageTransportSurfaceOverlayMacEGL::BufferPresented,
                          weak_ptr_factory_.GetWeakPtr());

  auto gl_make_current_callback =
      base::BindRepeating(&SharedContextState::MakeCurrent, context_state,
                          /*surface=*/nullptr, /*needs_gl=*/true);

  ca_layer_tree_coordinator_ = std::make_unique<ui::CALayerTreeCoordinator>(
      !av_disabled_at_command_line, std::move(buffer_presented_callback),
      std::move(gl_make_current_callback), GetMTLDevice(context_state));

#if BUILDFLAG(IS_IOS) && !BUILDFLAG(IS_IOS_TVOS)
  // The BELayerHierarchy needs to be created on a thread that supports
  // libdispatch, so we proxy over to the main dispatch queue to do that.
  CALayer* root_ca_layer = ca_layer_tree_coordinator_->root_ca_layer();
  __block xpc_object_t ipc_representation;
  dispatch_sync(dispatch_get_main_queue(), ^{
    NSError* error = nullptr;
    layer_hierarchy_ = [BELayerHierarchy layerHierarchyWithError:&error];
    layer_hierarchy_.layer = root_ca_layer;
    ipc_representation = [layer_hierarchy_.handle createXPCRepresentation];
  });

  BELayerHierarchyTransport* transport =
      BELayerHierarchyTransport::GetInstance();
  CHECK(transport);
  transport->ForwardBELayerHierarchyToBrowser(surface_handle,
                                              ipc_representation);
#endif
}

// For testing
ImageTransportSurfaceOverlayMacEGL::ImageTransportSurfaceOverlayMacEGL(
    std::unique_ptr<ui::CALayerTreeCoordinator> ca_layer_tree_coordinator
#if BUILDFLAG(IS_MAC)
    ,
    std::unique_ptr<ui::VSyncCallbackMac> vsync_callback_mac
#endif
    )
    : ca_layer_tree_coordinator_(std::move(ca_layer_tree_coordinator)),
#if BUILDFLAG(IS_MAC)
      vsync_callback_mac_(std::move(vsync_callback_mac)),
#endif
      weak_ptr_factory_(this) {
}

ImageTransportSurfaceOverlayMacEGL::~ImageTransportSurfaceOverlayMacEGL() {
  ca_layer_tree_coordinator_.reset();

#if BUILDFLAG(IS_IOS) && !BUILDFLAG(IS_IOS_TVOS)
  // Capture and retain the BELayerHierarchy in a local __block var before
  // dropping the member var ref. Do this before dispatch_async() to avoid a
  // dealloc race between the block and the member var releasing the last ref.
  __block BELayerHierarchy* layer_hierarchy =
      std::exchange(layer_hierarchy_, nil);
  dispatch_async(dispatch_get_main_queue(), ^{
    [layer_hierarchy invalidate];
    layer_hierarchy = nil;
  });
#endif
}

void ImageTransportSurfaceOverlayMacEGL::BufferPresented(
    PresentationCallback callback,
    const gfx::PresentationFeedback& feedback) {
  DCHECK(!callback.is_null());
  std::move(callback).Run(feedback);
}

void ImageTransportSurfaceOverlayMacEGL::Present(
    SwapCompletionCallback completion_callback,
    PresentationCallback presentation_callback,
    gfx::FrameData data) {
  TRACE_EVENT0("gpu", "ImageTransportSurfaceOverlayMac::Present");
  ca_layer_tree_coordinator_->SetCALayerErrorCode(data.ca_layer_error_code);

  // Commit the first pending frame before adding one more in Present() if there
  // are more than supported .
  if (ca_layer_tree_coordinator_->NumPendingSwaps() >= cap_max_pending_swaps_) {
    TRACE_EVENT0("gpu", "Exceeds the max pending swaps. Commit now.");
    CommitPresentedFrameToCA();
  }

  // Set the display HDR headroom to be used for any tone mapping to be done
  // at the CoreAnimation level.
  ca_layer_tree_coordinator_->GetPendingCARendererLayerTree()
      ->SetDisplayHDRHeadroom(data.display_hdr_headroom);

  ca_layer_tree_coordinator_->Present(std::move(completion_callback),
                                      std::move(presentation_callback));

#if BUILDFLAG(IS_MAC)
  if (display_link_mac_ && !vsync_callback_mac_) {
    vsync_callback_mac_ =
        display_link_mac_->RegisterCallback(base::BindRepeating(
            &ImageTransportSurfaceOverlayMacEGL::OnVSyncPresentation,
            weak_ptr_factory_.GetWeakPtr()));
  }

  bool delay_presenetation_until_next_vsync =
      features::IsVSyncAlignedPresentEnabled() && data.is_handling_interaction;

  // The current frame has been added to
  // ca_layer_tree_coordinator_->NumPendingSwaps() after calling
  // ca_layer_tree_coordinator_->Present(). Check NumPendingSwaps() > 1 to see
  // whether there is any previous pending frame. The current frame must wait in
  // the queue if there is already one before this.
  if (features::IsVSyncAlignedPresentEnabled() &&
      ca_layer_tree_coordinator_->NumPendingSwaps() > 1) {
    delay_presenetation_until_next_vsync = true;
  }

  if (vsync_callback_mac_) {
    vsync_callback_mac_keep_alive_counter_ = kMaxKeepAliveCounter;
    if (delay_presenetation_until_next_vsync) {
      // Delay CommitPresentedFrameToCA() until OnVSyncPresentation().
      return;
    }
  }
#endif

  CommitPresentedFrameToCA();
}

void ImageTransportSurfaceOverlayMacEGL::CommitPresentedFrameToCA() {
  //  Do a GL fence for flush to apply back-pressure before drawing.
  {
    base::TimeTicks start_time = base::TimeTicks::Now();
    ca_layer_tree_coordinator_->ApplyBackpressure();
    UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES(
        "Gpu.Mac.BackpressureUs", base::TimeTicks::Now() - start_time,
        kHistogramMinTime, kHistogramMaxTime, kHistogramTimeBuckets);
  }

  // Update the CALayer tree in the GPU process.
  {
    base::TimeTicks display_time;
    base::TimeDelta frame_interval;
#if BUILDFLAG(IS_MAC)
    display_time = GetDisplaytime(base::TimeTicks::Now());
    frame_interval = frame_interval_;
#endif
    TRACE_EVENT1("gpu", "CommitPresentedFrameToCA", "now_to_display",
                 (display_time - base::TimeTicks::Now()).InMicroseconds());
    ca_layer_tree_coordinator_->CommitPresentedFrameToCA(frame_interval,
                                                         display_time);
  }
}

bool ImageTransportSurfaceOverlayMacEGL::ScheduleCALayer(
    const ui::CARendererLayerParams& params,
    std::vector<gfx::MTLSharedEventFence> backpressure_fences) {
  ca_layer_tree_coordinator_->EnqueueBackpressureFences(
      std::move(backpressure_fences));
  return ca_layer_tree_coordinator_->GetPendingCARendererLayerTree()
      ->ScheduleCALayer(params);
}

bool ImageTransportSurfaceOverlayMacEGL::Resize(
    const gfx::Size& pixel_size,
    float scale_factor,
    const gfx::ColorSpace& color_space,
    bool has_alpha) {
  ca_layer_tree_coordinator_->Resize(pixel_size, scale_factor);
  return true;
}

void ImageTransportSurfaceOverlayMacEGL::SetMaxPendingSwaps(
    int max_pending_swaps) {
#if BUILDFLAG(IS_MAC)
  cap_max_pending_swaps_ = max_pending_swaps;

  // MaxCALayerTrees is equal to the number of max_pending_swaps + one
  // that has been displayed.
  ca_layer_tree_coordinator_->SetMaxCALayerTrees(cap_max_pending_swaps_ + 1);
#endif
}

#if BUILDFLAG(IS_MAC)
void ImageTransportSurfaceOverlayMacEGL::SetVSyncDisplayID(int64_t display_id) {
  if ((!display_link_mac_ || display_id != display_id_) &&
      display_id != display::kInvalidDisplayId) {
    vsync_callback_mac_ = nullptr;

    // Commit all pending frames before switching to the new monitor.
    while (ca_layer_tree_coordinator_->NumPendingSwaps()) {
      vsync_callback_mac_keep_alive_counter_ =
          std::max(vsync_callback_mac_keep_alive_counter_, 1);
      OnVSyncPresentation(ui::VSyncParamsMac());
    }

    display_link_mac_ = ui::DisplayLinkMac::GetForDisplay(display_id);
  }
  display_id_ = display_id;
}

base::TimeTicks ImageTransportSurfaceOverlayMacEGL::GetDisplaytime(
    base::TimeTicks latch_time) {
  // From the CVDisplayLink params dump:
  // |next_display_time_| ~= |current_display_time_| + |frame_interval|.
  // params.display_time ~= params.callback_time + 1.5x |frame_interval|.

  // From the experiment, frames committed before (|current_display_time_| - 1.5
  // ms) will be displayed at the next display time. 1.5 ms is roughly the safe
  // zone for the latch deadline. The result is inconsistent in the experiment
  // if commit is too close to the display_time.
  constexpr base::TimeDelta kLatchBufferTime = base::Microseconds(1500);
  auto latch_deadline_for_next_display =
      current_display_time_ - kLatchBufferTime;
  if (latch_time < latch_deadline_for_next_display) {
    return next_display_time_;
  }

  // We just missed the |current_display_time|, the display will be at the next
  // one after |next_display_time_|.
  if (!frame_interval_.is_zero() && next_display_time_ != base::TimeTicks()) {
    base::TimeTicks present_time =
        latch_time.SnappedToNextTick(next_display_time_ - kLatchBufferTime,
                                     frame_interval_) +
        kLatchBufferTime + frame_interval_;
    return present_time;
  }

  // When there is no display_time info, just use the latch_time.
  // This only happens at the very first frame after the browser starts,
  return latch_time;
}

// The CVDisplayLink callback on the GPU thread.
void ImageTransportSurfaceOverlayMacEGL::OnVSyncPresentation(
    ui::VSyncParamsMac params) {
  // Documentation for the CVDisplayLink display_time
  // https://developer.apple.com/documentation/corevideo/cvdisplaylinkoutputcallback

  base::TimeDelta callback_delay;
  base::TimeDelta callback_timebase_to_display;
  if (params.callback_times_valid && params.display_times_valid) {
    callback_delay = base::TimeTicks::Now() - params.callback_timebase;
    callback_timebase_to_display =
        params.display_timebase - params.callback_timebase;
  }
  TRACE_EVENT2("gpu", "OnVSyncPresentation", "callback_timebase_to_display",
               callback_timebase_to_display.InMicroseconds(), "callback_delay",
               callback_delay.InMicroseconds());

  current_display_time_ = next_display_time_;

  if (params.display_times_valid) {
    next_display_time_ = params.display_timebase;
    frame_interval_ = params.display_interval;
  }

  if (params.callback_times_valid &&
      base::ShouldRecordSubsampledMetric(0.001)) {
    RecordVSyncCallbackDelay(base::TimeTicks::Now() - params.callback_timebase);
  }

  if (ca_layer_tree_coordinator_->NumPendingSwaps()) {
    CommitPresentedFrameToCA();
  }

  vsync_callback_mac_keep_alive_counter_--;

  if (vsync_callback_mac_keep_alive_counter_ == 0) {
    vsync_callback_mac_ = nullptr;
  }
}

#endif
}  // namespace gpu