/* 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 "WebTaskSchedulerMainThread.h"

#include "mozilla/dom/TimeoutManager.h"
#include "nsContentUtils.h"
#include "nsGlobalWindowInner.h"

namespace mozilla::dom {

constinit uint32_t gNumNormalOrHighPriorityQueuesHaveTaskScheduledMainThread =
    0;

NS_IMETHODIMP WebTaskMainThreadRunnable::Run() {
  if (mScheduler) {
    RefPtr<WebTask> task = mScheduler->GetNextTask(true /* aIsMainThread */);
    if (task) {
      task->Run();
    }
  }
  return NS_OK;
}

nsresult WebTaskSchedulerMainThread::SetTimeoutForDelayedTask(
    WebTask* aTask, uint64_t aDelay, EventQueuePriority aPriority) {
  JSContext* cx = nsContentUtils::GetCurrentJSContext();
  if (!cx) {
    return NS_ERROR_UNEXPECTED;
  }
  nsIGlobalObject* global = GetParentObject();
  MOZ_ASSERT(global);

  RefPtr<DelayedWebTaskHandler> handler =
      new DelayedWebTaskHandler(cx, this, aTask, aPriority);

  int32_t delay = aDelay > INT32_MAX ? INT32_MAX : (int32_t)aDelay;

  int32_t handle;
  return nsGlobalWindowInner::Cast(global->GetAsInnerWindow())
      ->GetTimeoutManager()
      ->SetTimeout(handler, delay, /* aIsInterval */ false,
                   Timeout::Reason::eDelayedWebTaskTimeout, &handle);
}

bool WebTaskSchedulerMainThread::DispatchEventLoopRunnable(
    EventQueuePriority aPriority) {
  RefPtr<WebTaskMainThreadRunnable> runnable =
      new WebTaskMainThreadRunnable(this);

  MOZ_ALWAYS_SUCCEEDS(
      NS_DispatchToMainThreadQueue(runnable.forget(), aPriority));
  return true;
}

void WebTaskSchedulerMainThread::
    IncreaseNumNormalOrHighPriorityQueuesHaveTaskScheduled() {
  ++gNumNormalOrHighPriorityQueuesHaveTaskScheduledMainThread;
}

void WebTaskSchedulerMainThread::
    DecreaseNumNormalOrHighPriorityQueuesHaveTaskScheduled() {
  MOZ_DIAGNOSTIC_ASSERT(
      gNumNormalOrHighPriorityQueuesHaveTaskScheduledMainThread > 0);
  --gNumNormalOrHighPriorityQueuesHaveTaskScheduledMainThread;
}
}  // namespace mozilla::dom