/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* 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 "ActiveElementManager.h"

#include "mozilla/EventStateManager.h"

#include "mozilla/EventStates.h"

#include "mozilla/Preferences.h"

#include "base/message_loop.h"

#include "base/task.h"

#include "mozilla/dom/Element.h"

#include "nsIDocument.h"

#define AEM_LOG(...)

// #define AEM_LOG(...) printf_stderr("AEM: " __VA_ARGS__)

namespace mozilla {

namespace layers {

static int32_t sActivationDelayMs = 100;

static bool sActivationDelayMsSet = false;

ActiveElementManager::ActiveElementManager()

  : mCanBePan(false),

    mCanBePanSet(false),

    mSetActiveTask(nullptr)

{

  if (!sActivationDelayMsSet) {

    Preferences::AddIntVarCache(&sActivationDelayMs,

                                "ui.touch_activation.delay_ms",

                                sActivationDelayMs);

    sActivationDelayMsSet = true;

  }

}

ActiveElementManager::~ActiveElementManager() {}

void

ActiveElementManager::SetTargetElement(dom::EventTarget* aTarget)

{

  if (mTarget) {

    // Multiple fingers on screen (since HandleTouchEnd clears mTarget).

    AEM_LOG("Multiple fingers on-screen, clearing target element\n");

    CancelTask();

    ResetActive();

    ResetTouchBlockState();

    return;

  }

  mTarget = do_QueryInterface(aTarget);

  AEM_LOG("Setting target element to %p\n", mTarget.get());

  TriggerElementActivation();

}

void

ActiveElementManager::HandleTouchStart(bool aCanBePan)

{

  AEM_LOG("Touch start, aCanBePan: %d\n", aCanBePan);

  if (mCanBePanSet) {

    // Multiple fingers on screen (since HandleTouchEnd clears mCanBePanSet).

    AEM_LOG("Multiple fingers on-screen, clearing touch block state\n");

    CancelTask();

    ResetActive();

    ResetTouchBlockState();

    return;

  }

  mCanBePan = aCanBePan;

  mCanBePanSet = true;

  TriggerElementActivation();

}

void

ActiveElementManager::TriggerElementActivation()

{

  // Both HandleTouchStart() and SetTargetElement() call this. They can be

  // called in either order. One will set mCanBePanSet, and the other, mTarget.

  // We want to actually trigger the activation once both are set.

  if (!(mTarget && mCanBePanSet)) {

    return;

  }

  // If the touch cannot be a pan, make mTarget :active right away.

  // Otherwise, wait a bit to see if the user will pan or not.

  if (!mCanBePan) {

    SetActive(mTarget);

  } else {

    CancelTask();   // this is only needed because of bug 1169802. Fixing that

                    // bug properly should make this unnecessary.

    MOZ_ASSERT(mSetActiveTask == nullptr);

    RefPtr<CancelableRunnable> task =

      NewCancelableRunnableMethod<nsCOMPtr<dom::Element>>(

        "layers::ActiveElementManager::SetActiveTask",

        this,

        &ActiveElementManager::SetActiveTask,

        mTarget);

    mSetActiveTask = task;

    MessageLoop::current()->PostDelayedTask(task.forget(), sActivationDelayMs);

    AEM_LOG("Scheduling mSetActiveTask %p\n", mSetActiveTask);

  }

}

void

ActiveElementManager::ClearActivation()

{

  AEM_LOG("Clearing element activation\n");

  CancelTask();

  ResetActive();

}

void

ActiveElementManager::HandleTouchEndEvent(bool aWasClick)

{

  AEM_LOG("Touch end event, aWasClick: %d\n", aWasClick);

  // If the touch was a click, make mTarget :active right away.

  // nsEventStateManager will reset the active element when processing

  // the mouse-down event generated by the click.

  CancelTask();

  if (aWasClick) {

    // Scrollbar thumbs use a different mechanism for their active

    // highlight (the "active" attribute), so don't set the active state

    // on them because nothing will clear it.

    if (!(mTarget && mTarget->IsXULElement(nsGkAtoms::thumb))) {

      SetActive(mTarget);

    }

  } else {

    // We might reach here if mCanBePan was false on touch-start and

    // so we set the element active right away. Now it turns out the

    // action was not a click so we need to reset the active element.

    ResetActive();

  }

  ResetTouchBlockState();

}

void

ActiveElementManager::HandleTouchEnd()

{

  AEM_LOG("Touch end, clearing pan state\n");

  mCanBePanSet = false;

}

static nsPresContext*

GetPresContextFor(nsIContent* aContent)

{

  if (!aContent) {

    return nullptr;

  }

  nsIPresShell* shell = aContent->OwnerDoc()->GetShell();

  if (!shell) {

    return nullptr;

  }

  return shell->GetPresContext();

}

void

ActiveElementManager::SetActive(dom::Element* aTarget)

{

  AEM_LOG("Setting active %p\n", aTarget);

  if (nsPresContext* pc = GetPresContextFor(aTarget)) {

    pc->EventStateManager()->SetContentState(aTarget, NS_EVENT_STATE_ACTIVE);

  }

}

void

ActiveElementManager::ResetActive()

{

  AEM_LOG("Resetting active from %p\n", mTarget.get());

  // Clear the :active flag from mTarget by setting it on the document root.

  if (mTarget) {

    dom::Element* root = mTarget->OwnerDoc()->GetDocumentElement();

    if (root) {

      AEM_LOG("Found root %p, making active\n", root);

      SetActive(root);

    }

  }

}

void

ActiveElementManager::ResetTouchBlockState()

{

  mTarget = nullptr;

  mCanBePanSet = false;

}

void

ActiveElementManager::SetActiveTask(const nsCOMPtr<dom::Element>& aTarget)

{

  AEM_LOG("mSetActiveTask %p running\n", mSetActiveTask);

  // This gets called from mSetActiveTask's Run() method. The message loop

  // deletes the task right after running it, so we need to null out

  // mSetActiveTask to make sure we're not left with a dangling pointer.

  mSetActiveTask = nullptr;

  SetActive(aTarget);

}

void

ActiveElementManager::CancelTask()

{

  AEM_LOG("Cancelling task %p\n", mSetActiveTask);

  if (mSetActiveTask) {

    mSetActiveTask->Cancel();

    mSetActiveTask = nullptr;

  }

}

} // namespace layers

} // namespace mozilla