// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "flutter/shell/gpu/gpu_surface_vulkan_impeller.h"

#include "flow/surface_frame.h"
#include "flutter/fml/make_copyable.h"
#include "impeller/display_list/dl_dispatcher.h"
#include "impeller/renderer/backend/vulkan/surface_context_vk.h"
#include "impeller/renderer/surface.h"
#include "impeller/typographer/backends/skia/typographer_context_skia.h"

namespace flutter {

GPUSurfaceVulkanImpeller::GPUSurfaceVulkanImpeller(
    std::shared_ptr<impeller::Context> context) {
  if (!context || !context->IsValid()) {
    return;
  }

  auto aiks_context = std::make_shared<impeller::AiksContext>(
      context, impeller::TypographerContextSkia::Make());
  if (!aiks_context->IsValid()) {
    return;
  }

  impeller_context_ = std::move(context);
  aiks_context_ = std::move(aiks_context);
  is_valid_ = true;
}

// |Surface|
GPUSurfaceVulkanImpeller::~GPUSurfaceVulkanImpeller() = default;

// |Surface|
bool GPUSurfaceVulkanImpeller::IsValid() {
  return is_valid_;
}

// |Surface|
std::unique_ptr<SurfaceFrame> GPUSurfaceVulkanImpeller::AcquireFrame(
    const SkISize& size) {
  if (!IsValid()) {
    FML_LOG(ERROR) << "Vulkan surface was invalid.";
    return nullptr;
  }

  if (size.isEmpty()) {
    FML_LOG(ERROR) << "Vulkan surface was asked for an empty frame.";
    return nullptr;
  }

  auto& context_vk = impeller::SurfaceContextVK::Cast(*impeller_context_);
  std::unique_ptr<impeller::Surface> surface = context_vk.AcquireNextSurface();

  if (!surface) {
    FML_LOG(ERROR) << "No surface available.";
    return nullptr;
  }

  auto cull_rect =
      surface->GetTargetRenderPassDescriptor().GetRenderTargetSize();

  const impeller::RenderTarget& render_target =
      surface->GetTargetRenderPassDescriptor();

  SurfaceFrame::EncodeCallback encode_callback = [aiks_context =
                                                      aiks_context_,  //
                                                  render_target,
                                                  cull_rect  //
  ](SurfaceFrame& surface_frame, DlCanvas* canvas) mutable -> bool {
    if (!aiks_context) {
      return false;
    }

    auto display_list = surface_frame.BuildDisplayList();
    if (!display_list) {
      FML_LOG(ERROR) << "Could not build display list for surface frame.";
      return false;
    }

#if EXPERIMENTAL_CANVAS
    impeller::TextFrameDispatcher collector(aiks_context->GetContentContext(),
                                            impeller::Matrix());
    display_list->Dispatch(collector,
                           SkIRect::MakeWH(cull_rect.width, cull_rect.height));
    impeller::ExperimentalDlDispatcher impeller_dispatcher(
        aiks_context->GetContentContext(), render_target,
        display_list->root_has_backdrop_filter(),
        display_list->max_root_blend_mode(),
        impeller::IRect::RoundOut(impeller::Rect::MakeSize(cull_rect)));
    display_list->Dispatch(impeller_dispatcher,
                           SkIRect::MakeWH(cull_rect.width, cull_rect.height));
    impeller_dispatcher.FinishRecording();
    aiks_context->GetContentContext().GetTransientsBuffer().Reset();
    aiks_context->GetContentContext().GetLazyGlyphAtlas()->ResetTextFrames();
    return true;
#else
    impeller::Rect dl_cull_rect = impeller::Rect::MakeSize(cull_rect);
    impeller::DlDispatcher impeller_dispatcher(dl_cull_rect);
    display_list->Dispatch(impeller_dispatcher,
                           SkIRect::MakeWH(cull_rect.width, cull_rect.height));
    auto picture = impeller_dispatcher.EndRecordingAsPicture();
    const bool reset_host_buffer = surface_frame.submit_info().frame_boundary;
    return aiks_context->Render(picture, render_target, reset_host_buffer);
#endif
  };

  return std::make_unique<SurfaceFrame>(
      nullptr,                          // surface
      SurfaceFrame::FramebufferInfo{},  // framebuffer info
      encode_callback,                  // encode callback
      fml::MakeCopyable([surface = std::move(surface)](const SurfaceFrame&) {
        return surface->Present();
      }),       // submit callback
      size,     // frame size
      nullptr,  // context result
      true      // display list fallback
  );
}

// |Surface|
SkMatrix GPUSurfaceVulkanImpeller::GetRootTransformation() const {
  // This backend does not currently support root surface transformations. Just
  // return identity.
  return {};
}

// |Surface|
GrDirectContext* GPUSurfaceVulkanImpeller::GetContext() {
  // Impeller != Skia.
  return nullptr;
}

// |Surface|
std::unique_ptr<GLContextResult>
GPUSurfaceVulkanImpeller::MakeRenderContextCurrent() {
  // This backend has no such concept.
  return std::make_unique<GLContextDefaultResult>(true);
}

// |Surface|
bool GPUSurfaceVulkanImpeller::EnableRasterCache() const {
  return false;
}

// |Surface|
std::shared_ptr<impeller::AiksContext>
GPUSurfaceVulkanImpeller::GetAiksContext() const {
  return aiks_context_;
}

}  // namespace flutter