// 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/lib/gpu/context.h"

#include <future>

#include "dart_api.h"
#include "flutter/lib/ui/ui_dart_state.h"
#include "fml/make_copyable.h"
#include "tonic/converter/dart_converter.h"

namespace flutter {

IMPLEMENT_WRAPPERTYPEINFO(gpu, Context);

Context::Context(std::shared_ptr<impeller::Context> context)
    : context_(std::move(context)) {}

Context::~Context() = default;

}  // namespace flutter

//----------------------------------------------------------------------------
/// Exports
///

Dart_Handle InternalFlutterGpu_Context_InitializeDefault(Dart_Handle wrapper) {
  auto dart_state = flutter::UIDartState::Current();
  if (!dart_state->IsImpellerEnabled()) {
    return tonic::ToDart(
        "Flutter GPU requires the Impeller rendering backend to be enabled.");
  }

  // Grab the Impeller context from the IO manager.

  std::promise<std::shared_ptr<impeller::Context>> context_promise;
  auto impeller_context_future = context_promise.get_future();
  dart_state->GetTaskRunners().GetIOTaskRunner()->PostTask(
      fml::MakeCopyable([promise = std::move(context_promise),
                         io_manager = dart_state->GetIOManager()]() mutable {
        promise.set_value(io_manager ? io_manager->GetImpellerContext()
                                     : nullptr);
      }));

  auto impeller_context = impeller_context_future.get();
  if (!impeller_context) {
    return tonic::ToDart("Unable to retrieve the Impeller context.");
  }
  auto res = fml::MakeRefCounted<flutter::Context>(impeller_context);
  res->AssociateWithDartWrapper(wrapper);

  return Dart_Null();
}