// Copyright 2022 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "cobalt/web/message_port.h"

#include <memory>
#include <string>
#include <utility>

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/logging.h"
#include "base/memory/ptr_util.h"
#include "base/memory/ref_counted.h"
#include "base/message_loop/message_loop.h"
#include "base/task_runner.h"
#include "cobalt/script/environment_settings.h"
#include "cobalt/web/context.h"
#include "cobalt/web/event.h"
#include "cobalt/web/event_target.h"
#include "cobalt/web/message_event.h"

namespace cobalt {
namespace web {

MessagePort::MessagePort(web::EventTarget* event_target)
    : event_target_(event_target) {
  if (!event_target_) {
    return;
  }
  Context* context = event_target_->environment_settings()->context();
  base::MessageLoop* message_loop = context->message_loop();
  if (!message_loop) {
    return;
  }
  message_loop->task_runner()->PostTask(
      FROM_HERE,
      base::BindOnce(&Context::AddEnvironmentSettingsChangeObserver,
                     base::Unretained(context), base::Unretained(this)));
  remove_environment_settings_change_observer_ =
      base::BindOnce(&Context::RemoveEnvironmentSettingsChangeObserver,
                     base::Unretained(context), base::Unretained(this));
}

MessagePort::~MessagePort() { Close(); }

void MessagePort::Close() {
  if (!event_target_) {
    return;
  }
  if (remove_environment_settings_change_observer_) {
    std::move(remove_environment_settings_change_observer_).Run();
  }
  event_target_ = nullptr;
}

void MessagePort::PostMessage(const script::ValueHandleHolder& message) {
  PostMessageSerialized(std::make_unique<script::StructuredClone>(message));
}

void MessagePort::PostMessageSerialized(
    std::unique_ptr<script::StructuredClone> structured_clone) {
  if (!event_target_ || !structured_clone) {
    return;
  }
  // TODO: Forward the location of the origating API call to the PostTask call.
  base::MessageLoop* message_loop =
      event_target_->environment_settings()->context()->message_loop();
  if (!message_loop) {
    return;
  }
  //   https://html.spec.whatwg.org/multipage/workers.html#handler-worker-onmessage
  // TODO: Update MessageEvent to support more types. (b/227665847)
  // TODO: Remove dependency of MessageEvent on net iobuffer (b/227665847)
  message_loop->task_runner()->PostTask(
      FROM_HERE, base::BindOnce(&MessagePort::DispatchMessage, AsWeakPtr(),
                                std::move(structured_clone)));
}

void MessagePort::DispatchMessage(
    std::unique_ptr<script::StructuredClone> structured_clone) {
  event_target_->DispatchEvent(new web::MessageEvent(
      base::Tokens::message(), std::move(structured_clone)));
}

}  // namespace web
}  // namespace cobalt