/* -*- 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 "WheelHandlingHelper.h"

#include "mozilla/EventDispatcher.h"

#include "mozilla/EventStateManager.h"

#include "mozilla/MouseEvents.h"

#include "mozilla/Preferences.h"

#include "nsCOMPtr.h"

#include "nsContentUtils.h"

#include "nsIContent.h"

#include "nsIDocument.h"

#include "nsIPresShell.h"

#include "nsIScrollableFrame.h"

#include "nsITextControlElement.h"

#include "nsITimer.h"

#include "nsPluginFrame.h"

#include "nsPresContext.h"

#include "prtime.h"

#include "Units.h"

#include "ScrollAnimationPhysics.h"

namespace mozilla {

/******************************************************************/

/* mozilla::DeltaValues                                           */

/******************************************************************/

DeltaValues::DeltaValues(WidgetWheelEvent* aEvent)

    : deltaX(aEvent->mDeltaX), deltaY(aEvent->mDeltaY) {}

/******************************************************************/

/* mozilla::WheelHandlingUtils                                    */

/******************************************************************/

/* static */ bool WheelHandlingUtils::CanScrollInRange(nscoord aMin,

                                                       nscoord aValue,

                                                       nscoord aMax,

                                                       double aDirection) {

  return aDirection > 0.0 ? aValue < static_cast<double>(aMax)

                          : static_cast<double>(aMin) < aValue;

}

/* static */ bool WheelHandlingUtils::CanScrollOn(nsIFrame* aFrame,

                                                  double aDirectionX,

                                                  double aDirectionY) {

  nsIScrollableFrame* scrollableFrame = do_QueryFrame(aFrame);

  if (scrollableFrame) {

    return CanScrollOn(scrollableFrame, aDirectionX, aDirectionY);

  }

  nsPluginFrame* pluginFrame = do_QueryFrame(aFrame);

  return pluginFrame && pluginFrame->WantsToHandleWheelEventAsDefaultAction();

}

/* static */ bool WheelHandlingUtils::CanScrollOn(

    nsIScrollableFrame* aScrollFrame, double aDirectionX, double aDirectionY) {

  MOZ_ASSERT(aScrollFrame);

  NS_ASSERTION(aDirectionX || aDirectionY,

               "One of the delta values must be non-zero at least");

  nsPoint scrollPt = aScrollFrame->GetScrollPosition();

  nsRect scrollRange = aScrollFrame->GetScrollRange();

  uint32_t directions = aScrollFrame->GetPerceivedScrollingDirections();

  return (aDirectionX && (directions & nsIScrollableFrame::HORIZONTAL) &&

          CanScrollInRange(scrollRange.x, scrollPt.x, scrollRange.XMost(),

                           aDirectionX)) ||

         (aDirectionY && (directions & nsIScrollableFrame::VERTICAL) &&

          CanScrollInRange(scrollRange.y, scrollPt.y, scrollRange.YMost(),

                           aDirectionY));

}

/*static*/ Maybe<layers::ScrollDirection>

WheelHandlingUtils::GetDisregardedWheelScrollDirection(const nsIFrame* aFrame) {

  nsIContent* content = aFrame->GetContent();

  if (!content) {

    return Nothing();

  }

  nsCOMPtr<nsITextControlElement> ctrl = do_QueryInterface(

      content->IsInAnonymousSubtree() ? content->GetBindingParent() : content);

  if (!ctrl || !ctrl->IsSingleLineTextControl()) {

    return Nothing();

  }

  // Disregard scroll in the block-flow direction by mouse wheel on a

  // single-line text control. For instance, in tranditional Chinese writing

  // system, a single-line text control cannot be scrolled horizontally with

  // mouse wheel even if they overflow at the right and left edges; Whereas in

  // latin-based writing system, a single-line text control cannot be scrolled

  // vertically with mouse wheel even if they overflow at the top and bottom

  // edges

  return Some(aFrame->GetWritingMode().IsVertical()

                  ? layers::ScrollDirection::eHorizontal

                  : layers::ScrollDirection::eVertical);

}

/******************************************************************/

/* mozilla::WheelTransaction                                      */

/******************************************************************/

AutoWeakFrame WheelTransaction::sTargetFrame(nullptr);

uint32_t WheelTransaction::sTime = 0;

uint32_t WheelTransaction::sMouseMoved = 0;

nsITimer* WheelTransaction::sTimer = nullptr;

int32_t WheelTransaction::sScrollSeriesCounter = 0;

bool WheelTransaction::sOwnScrollbars = false;

/* static */ bool WheelTransaction::OutOfTime(uint32_t aBaseTime,

                                              uint32_t aThreshold) {

  uint32_t now = PR_IntervalToMilliseconds(PR_IntervalNow());

  return (now - aBaseTime > aThreshold);

}

/* static */ void WheelTransaction::OwnScrollbars(bool aOwn) {

  sOwnScrollbars = aOwn;

}

/* static */ void WheelTransaction::BeginTransaction(

    nsIFrame* aTargetFrame, const WidgetWheelEvent* aEvent) {

  NS_ASSERTION(!sTargetFrame, "previous transaction is not finished!");

  MOZ_ASSERT(aEvent->mMessage == eWheel,

             "Transaction must be started with a wheel event");

  ScrollbarsForWheel::OwnWheelTransaction(false);

  sTargetFrame = aTargetFrame;

  sScrollSeriesCounter = 0;

  if (!UpdateTransaction(aEvent)) {

    NS_ERROR("BeginTransaction is called even cannot scroll the frame");

    EndTransaction();

  }

}

/* static */ bool WheelTransaction::UpdateTransaction(

    const WidgetWheelEvent* aEvent) {

  nsIFrame* scrollToFrame = GetTargetFrame();

  nsIScrollableFrame* scrollableFrame = scrollToFrame->GetScrollTargetFrame();

  if (scrollableFrame) {

    scrollToFrame = do_QueryFrame(scrollableFrame);

  }

  if (!WheelHandlingUtils::CanScrollOn(scrollToFrame, aEvent->mDeltaX,

                                       aEvent->mDeltaY)) {

    OnFailToScrollTarget();

    // We should not modify the transaction state when the view will not be

    // scrolled actually.

    return false;

  }

  SetTimeout();

  if (sScrollSeriesCounter != 0 && OutOfTime(sTime, kScrollSeriesTimeoutMs)) {

    sScrollSeriesCounter = 0;

  }

  sScrollSeriesCounter++;

  // We should use current time instead of WidgetEvent.time.

  // 1. Some events doesn't have the correct creation time.

  // 2. If the computer runs slowly by other processes eating the CPU resource,

  //    the event creation time doesn't keep real time.

  sTime = PR_IntervalToMilliseconds(PR_IntervalNow());

  sMouseMoved = 0;

  return true;

}

/* static */ void WheelTransaction::MayEndTransaction() {

  if (!sOwnScrollbars && ScrollbarsForWheel::IsActive()) {

    ScrollbarsForWheel::OwnWheelTransaction(true);

  } else {

    EndTransaction();

  }

}

/* static */ void WheelTransaction::EndTransaction() {

  if (sTimer) {

    sTimer->Cancel();

  }

  sTargetFrame = nullptr;

  sScrollSeriesCounter = 0;

  if (sOwnScrollbars) {

    sOwnScrollbars = false;

    ScrollbarsForWheel::OwnWheelTransaction(false);

    ScrollbarsForWheel::Inactivate();

  }

}

/* static */ bool WheelTransaction::WillHandleDefaultAction(

    WidgetWheelEvent* aWheelEvent, AutoWeakFrame& aTargetWeakFrame) {

  nsIFrame* lastTargetFrame = GetTargetFrame();

  if (!lastTargetFrame) {

    BeginTransaction(aTargetWeakFrame.GetFrame(), aWheelEvent);

  } else if (lastTargetFrame != aTargetWeakFrame.GetFrame()) {

    EndTransaction();

    BeginTransaction(aTargetWeakFrame.GetFrame(), aWheelEvent);

  } else {

    UpdateTransaction(aWheelEvent);

  }

  // When the wheel event will not be handled with any frames,

  // UpdateTransaction() fires MozMouseScrollFailed event which is for

  // automated testing.  In the event handler, the target frame might be

  // destroyed.  Then, the caller shouldn't try to handle the default action.

  if (!aTargetWeakFrame.IsAlive()) {

    EndTransaction();

    return false;

  }

  return true;

}

/* static */ void WheelTransaction::OnEvent(WidgetEvent* aEvent) {

  if (!sTargetFrame) {

    return;

  }

  if (OutOfTime(sTime, GetTimeoutTime())) {

    // Even if the scroll event which is handled after timeout, but onTimeout

    // was not fired by timer, then the scroll event will scroll old frame,

    // therefore, we should call OnTimeout here and ensure to finish the old

    // transaction.

    OnTimeout(nullptr, nullptr);

    return;

  }

  switch (aEvent->mMessage) {

    case eWheel:

      if (sMouseMoved != 0 &&

          OutOfTime(sMouseMoved, GetIgnoreMoveDelayTime())) {

        // Terminate the current mousewheel transaction if the mouse moved more

        // than ignoremovedelay milliseconds ago

        EndTransaction();

      }

      return;

    case eMouseMove:

    case eDragOver: {

      WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent();

      if (mouseEvent->IsReal()) {

        // If the cursor is moving to be outside the frame,

        // terminate the scrollwheel transaction.

        LayoutDeviceIntPoint pt = GetScreenPoint(mouseEvent);

        auto r = LayoutDeviceIntRect::FromAppUnitsToNearest(

            sTargetFrame->GetScreenRectInAppUnits(),

            sTargetFrame->PresContext()->AppUnitsPerDevPixel());

        if (!r.Contains(pt)) {

          EndTransaction();

          return;

        }

        // If the cursor is moving inside the frame, and it is less than

        // ignoremovedelay milliseconds since the last scroll operation, ignore

        // the mouse move; otherwise, record the current mouse move time to be

        // checked later

        if (!sMouseMoved && OutOfTime(sTime, GetIgnoreMoveDelayTime())) {

          sMouseMoved = PR_IntervalToMilliseconds(PR_IntervalNow());

        }

      }

      return;

    }

    case eKeyPress:

    case eKeyUp:

    case eKeyDown:

    case eMouseUp:

    case eMouseDown:

    case eMouseDoubleClick:

    case eMouseAuxClick:

    case eMouseClick:

    case eContextMenu:

    case eDrop:

      EndTransaction();

      return;

    default:

      break;

  }

}

/* static */ void WheelTransaction::Shutdown() { NS_IF_RELEASE(sTimer); }

/* static */ void WheelTransaction::OnFailToScrollTarget() {

  NS_PRECONDITION(sTargetFrame, "We don't have mouse scrolling transaction");

  if (Prefs::sTestMouseScroll) {

    // This event is used for automated tests, see bug 442774.

    nsContentUtils::DispatchTrustedEvent(

        sTargetFrame->GetContent()->OwnerDoc(), sTargetFrame->GetContent(),

        NS_LITERAL_STRING("MozMouseScrollFailed"), true, true);

  }

  // The target frame might be destroyed in the event handler, at that time,

  // we need to finish the current transaction

  if (!sTargetFrame) {

    EndTransaction();

  }

}

/* static */ void WheelTransaction::OnTimeout(nsITimer* aTimer,

                                              void* aClosure) {

  if (!sTargetFrame) {

    // The transaction target was destroyed already

    EndTransaction();

    return;

  }

  // Store the sTargetFrame, the variable becomes null in EndTransaction.

  nsIFrame* frame = sTargetFrame;

  // We need to finish current transaction before DOM event firing. Because

  // the next DOM event might create strange situation for us.

  MayEndTransaction();

  if (Prefs::sTestMouseScroll) {

    // This event is used for automated tests, see bug 442774.

    nsContentUtils::DispatchTrustedEvent(

        frame->GetContent()->OwnerDoc(), frame->GetContent(),

        NS_LITERAL_STRING("MozMouseScrollTransactionTimeout"), true, true);

  }

}

/* static */ void WheelTransaction::SetTimeout() {

  if (!sTimer) {

    sTimer = NS_NewTimer().take();

    if (!sTimer) {

      return;

    }

  }

  sTimer->Cancel();

  DebugOnly<nsresult> rv = sTimer->InitWithNamedFuncCallback(

      OnTimeout, nullptr, GetTimeoutTime(), nsITimer::TYPE_ONE_SHOT,

      "WheelTransaction::SetTimeout");

  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),

                       "nsITimer::InitWithFuncCallback failed");

}

/* static */ LayoutDeviceIntPoint WheelTransaction::GetScreenPoint(

    WidgetGUIEvent* aEvent) {

  NS_ASSERTION(aEvent, "aEvent is null");

  NS_ASSERTION(aEvent->mWidget, "aEvent-mWidget is null");

  return aEvent->mRefPoint + aEvent->mWidget->WidgetToScreenOffset();

}

/* static */ DeltaValues WheelTransaction::AccelerateWheelDelta(

    WidgetWheelEvent* aEvent, bool aAllowScrollSpeedOverride) {

  DeltaValues result(aEvent);

  // Don't accelerate the delta values if the event isn't line scrolling.

  if (aEvent->mDeltaMode != nsIDOMWheelEvent::DOM_DELTA_LINE) {

    return result;

  }

  if (aAllowScrollSpeedOverride) {

    result = OverrideSystemScrollSpeed(aEvent);

  }

  // Accelerate by the sScrollSeriesCounter

  int32_t start = GetAccelerationStart();

  if (start >= 0 && sScrollSeriesCounter >= start) {

    int32_t factor = GetAccelerationFactor();

    if (factor > 0) {

      result.deltaX = ComputeAcceleratedWheelDelta(result.deltaX, factor);

      result.deltaY = ComputeAcceleratedWheelDelta(result.deltaY, factor);

    }

  }

  return result;

}

/* static */ double WheelTransaction::ComputeAcceleratedWheelDelta(

    double aDelta, int32_t aFactor) {

  return mozilla::ComputeAcceleratedWheelDelta(aDelta, sScrollSeriesCounter,

                                               aFactor);

}

/* static */ DeltaValues WheelTransaction::OverrideSystemScrollSpeed(

    WidgetWheelEvent* aEvent) {

  MOZ_ASSERT(sTargetFrame, "We don't have mouse scrolling transaction");

  MOZ_ASSERT(aEvent->mDeltaMode == nsIDOMWheelEvent::DOM_DELTA_LINE);

  // If the event doesn't scroll to both X and Y, we don't need to do anything

  // here.

  if (!aEvent->mDeltaX && !aEvent->mDeltaY) {

    return DeltaValues(aEvent);

  }

  return DeltaValues(aEvent->OverriddenDeltaX(), aEvent->OverriddenDeltaY());

}

/******************************************************************/

/* mozilla::ScrollbarsForWheel                                    */

/******************************************************************/

const DeltaValues ScrollbarsForWheel::directions[kNumberOfTargets] = {

    DeltaValues(-1, 0), DeltaValues(+1, 0), DeltaValues(0, -1),

    DeltaValues(0, +1)};

AutoWeakFrame ScrollbarsForWheel::sActiveOwner = nullptr;

AutoWeakFrame ScrollbarsForWheel::sActivatedScrollTargets[kNumberOfTargets] = {

    nullptr, nullptr, nullptr, nullptr};

bool ScrollbarsForWheel::sHadWheelStart = false;

bool ScrollbarsForWheel::sOwnWheelTransaction = false;

/* static */ void ScrollbarsForWheel::PrepareToScrollText(

    EventStateManager* aESM, nsIFrame* aTargetFrame, WidgetWheelEvent* aEvent) {

  if (aEvent->mMessage == eWheelOperationStart) {

    WheelTransaction::OwnScrollbars(false);

    if (!IsActive()) {

      TemporarilyActivateAllPossibleScrollTargets(aESM, aTargetFrame, aEvent);

      sHadWheelStart = true;

    }

  } else {

    DeactivateAllTemporarilyActivatedScrollTargets();

  }

}

/* static */ void ScrollbarsForWheel::SetActiveScrollTarget(

    nsIScrollableFrame* aScrollTarget) {

  if (!sHadWheelStart) {

    return;

  }

  nsIScrollbarMediator* scrollbarMediator = do_QueryFrame(aScrollTarget);

  if (!scrollbarMediator) {

    return;

  }

  sHadWheelStart = false;

  sActiveOwner = do_QueryFrame(aScrollTarget);

  scrollbarMediator->ScrollbarActivityStarted();

}

/* static */ void ScrollbarsForWheel::MayInactivate() {

  if (!sOwnWheelTransaction && WheelTransaction::GetTargetFrame()) {

    WheelTransaction::OwnScrollbars(true);

  } else {

    Inactivate();

  }

}

/* static */ void ScrollbarsForWheel::Inactivate() {

  nsIScrollbarMediator* scrollbarMediator = do_QueryFrame(sActiveOwner);

  if (scrollbarMediator) {

    scrollbarMediator->ScrollbarActivityStopped();

  }

  sActiveOwner = nullptr;

  DeactivateAllTemporarilyActivatedScrollTargets();

  if (sOwnWheelTransaction) {

    sOwnWheelTransaction = false;

    WheelTransaction::OwnScrollbars(false);

    WheelTransaction::EndTransaction();

  }

}

/* static */ bool ScrollbarsForWheel::IsActive() {

  if (sActiveOwner) {

    return true;

  }

  for (size_t i = 0; i < kNumberOfTargets; ++i) {

    if (sActivatedScrollTargets[i]) {

      return true;

    }

  }

  return false;

}

/* static */ void ScrollbarsForWheel::OwnWheelTransaction(bool aOwn) {

  sOwnWheelTransaction = aOwn;

}

/* static */ void

ScrollbarsForWheel::TemporarilyActivateAllPossibleScrollTargets(

    EventStateManager* aESM, nsIFrame* aTargetFrame, WidgetWheelEvent* aEvent) {

  for (size_t i = 0; i < kNumberOfTargets; i++) {

    const DeltaValues* dir = &directions[i];

    AutoWeakFrame* scrollTarget = &sActivatedScrollTargets[i];

    MOZ_ASSERT(!*scrollTarget, "scroll target still temporarily activated!");

    nsIScrollableFrame* target = do_QueryFrame(aESM->ComputeScrollTarget(

        aTargetFrame, dir->deltaX, dir->deltaY, aEvent,

        EventStateManager::COMPUTE_DEFAULT_ACTION_TARGET));

    nsIScrollbarMediator* scrollbarMediator = do_QueryFrame(target);

    if (scrollbarMediator) {

      nsIFrame* targetFrame = do_QueryFrame(target);

      *scrollTarget = targetFrame;

      scrollbarMediator->ScrollbarActivityStarted();

    }

  }

}

/* static */ void

ScrollbarsForWheel::DeactivateAllTemporarilyActivatedScrollTargets() {

  for (size_t i = 0; i < kNumberOfTargets; i++) {

    AutoWeakFrame* scrollTarget = &sActivatedScrollTargets[i];

    if (*scrollTarget) {

      nsIScrollbarMediator* scrollbarMediator = do_QueryFrame(*scrollTarget);

      if (scrollbarMediator) {

        scrollbarMediator->ScrollbarActivityStopped();

      }

      *scrollTarget = nullptr;

    }

  }

}

/******************************************************************/

/* mozilla::WheelTransaction::Prefs                               */

/******************************************************************/

int32_t WheelTransaction::Prefs::sMouseWheelAccelerationStart = -1;

int32_t WheelTransaction::Prefs::sMouseWheelAccelerationFactor = -1;

uint32_t WheelTransaction::Prefs::sMouseWheelTransactionTimeout = 1500;

uint32_t WheelTransaction::Prefs::sMouseWheelTransactionIgnoreMoveDelay = 100;

bool WheelTransaction::Prefs::sTestMouseScroll = false;

/* static */ void WheelTransaction::Prefs::InitializeStatics() {

  static bool sIsInitialized = false;

  if (!sIsInitialized) {

    Preferences::AddIntVarCache(&sMouseWheelAccelerationStart,

                                "mousewheel.acceleration.start", -1);

    Preferences::AddIntVarCache(&sMouseWheelAccelerationFactor,

                                "mousewheel.acceleration.factor", -1);

    Preferences::AddUintVarCache(&sMouseWheelTransactionTimeout,

                                 "mousewheel.transaction.timeout", 1500);

    Preferences::AddUintVarCache(&sMouseWheelTransactionIgnoreMoveDelay,

                                 "mousewheel.transaction.ignoremovedelay", 100);

    Preferences::AddBoolVarCache(&sTestMouseScroll, "test.mousescroll", false);

    sIsInitialized = true;

  }

}

/******************************************************************/

/* mozilla::AutoWheelDeltaAdjuster                                */

/******************************************************************/

AutoWheelDeltaAdjuster::AutoWheelDeltaAdjuster(WidgetWheelEvent& aWheelEvent)

    : mWheelEvent(aWheelEvent),

      mOldDeltaX(aWheelEvent.mDeltaX),

      mOldDeltaZ(aWheelEvent.mDeltaZ),

      mOldOverflowDeltaX(aWheelEvent.mOverflowDeltaX),

      mOldLineOrPageDeltaX(aWheelEvent.mLineOrPageDeltaX),

      mTreatedVerticalWheelAsHorizontalScroll(false) {

  MOZ_ASSERT(!aWheelEvent.mDeltaValuesAdjustedForDefaultHandler);

  if (EventStateManager::WheelEventIsHorizontalScrollAction(&aWheelEvent)) {

    // Move deltaY values to deltaX and set both deltaY and deltaZ to 0.

    mWheelEvent.mDeltaX = mWheelEvent.mDeltaY;

    mWheelEvent.mDeltaY = 0.0;

    mWheelEvent.mDeltaZ = 0.0;

    mWheelEvent.mOverflowDeltaX = mWheelEvent.mOverflowDeltaY;

    mWheelEvent.mOverflowDeltaY = 0.0;

    mWheelEvent.mLineOrPageDeltaX = mWheelEvent.mLineOrPageDeltaY;

    mWheelEvent.mLineOrPageDeltaY = 0;

    mWheelEvent.mDeltaValuesAdjustedForDefaultHandler = true;

    mTreatedVerticalWheelAsHorizontalScroll = true;

  }

}

AutoWheelDeltaAdjuster::~AutoWheelDeltaAdjuster() {

  if (mTreatedVerticalWheelAsHorizontalScroll &&

      mWheelEvent.mDeltaValuesAdjustedForDefaultHandler) {

    mWheelEvent.mDeltaY = mWheelEvent.mDeltaX;

    mWheelEvent.mDeltaX = mOldDeltaX;

    mWheelEvent.mDeltaZ = mOldDeltaZ;

    mWheelEvent.mOverflowDeltaY = mWheelEvent.mOverflowDeltaX;

    mWheelEvent.mOverflowDeltaX = mOldOverflowDeltaX;

    mWheelEvent.mLineOrPageDeltaY = mWheelEvent.mLineOrPageDeltaX;

    mWheelEvent.mLineOrPageDeltaX = mOldLineOrPageDeltaX;

    mWheelEvent.mDeltaValuesAdjustedForDefaultHandler = false;

  }

}

}  // namespace mozilla