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 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
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 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_ANIMATION_ANIMATION_EFFECT_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_ANIMATION_ANIMATION_EFFECT_H_

#include "base/optional.h"
#include "third_party/blink/renderer/core/animation/animation_time_delta.h"
#include "third_party/blink/renderer/core/animation/timing.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/platform/bindings/exception_state.h"
#include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
#include "third_party/blink/renderer/platform/heap/handle.h"

namespace blink {

class Animation;
enum class TimelinePhase;
class AnimationEffectOwner;
class EffectTiming;
class ComputedEffectTiming;
class OptionalEffectTiming;
class WorkletAnimation;

enum TimingUpdateReason {
  kTimingUpdateOnDemand,
  kTimingUpdateForAnimationFrame
};

// Represents the content of an Animation and its fractional timing state.
// https://drafts.csswg.org/web-animations/#the-animationeffect-interface
class CORE_EXPORT AnimationEffect : public ScriptWrappable {
  DEFINE_WRAPPERTYPEINFO();
  // Calls Attach/Detach, GetAnimation, UpdateInheritedTime.
  friend class Animation;
  friend class WorkletAnimation;

  // Calls GetAnimation().
  // TODO(majidvp): Remove this. EffectStack should not need to access animation
  // directly.
  friend class EffectStack;

 public:
  class EventDelegate : public GarbageCollected<EventDelegate> {
   public:
    virtual ~EventDelegate() = default;
    virtual bool RequiresIterationEvents(const AnimationEffect&) = 0;
    virtual void OnEventCondition(const AnimationEffect&, Timing::Phase) = 0;
    virtual bool IsAnimationEventDelegate() const { return false; }
    virtual bool IsTransitionEventDelegate() const { return false; }
    virtual void Trace(Visitor* visitor) const {}
  };

  ~AnimationEffect() override = default;

  virtual bool IsKeyframeEffect() const { return false; }
  virtual bool IsInertEffect() const { return false; }

  Timing::Phase GetPhase() const { return EnsureCalculated().phase; }
  bool IsCurrent() const { return EnsureCalculated().is_current; }
  bool IsInEffect() const { return EnsureCalculated().is_in_effect; }
  bool IsInPlay() const { return EnsureCalculated().is_in_play; }
  base::Optional<double> CurrentIteration() const {
    return EnsureCalculated().current_iteration;
  }
  base::Optional<double> Progress() const {
    return EnsureCalculated().progress;
  }
  AnimationTimeDelta TimeToForwardsEffectChange() const {
    return EnsureCalculated().time_to_forwards_effect_change;
  }
  AnimationTimeDelta TimeToReverseEffectChange() const {
    return EnsureCalculated().time_to_reverse_effect_change;
  }
  base::Optional<double> LocalTime() const {
    return EnsureCalculated().local_time;
  }

  const Timing& SpecifiedTiming() const { return timing_; }
  void UpdateSpecifiedTiming(const Timing&);
  void SetIgnoreCssTimingProperties();

  EventDelegate* GetEventDelegate() { return event_delegate_; }
  void SetEventDelegate(EventDelegate* delegate) { event_delegate_ = delegate; }

  EffectTiming* getTiming() const;
  ComputedEffectTiming* getComputedTiming() const;
  void updateTiming(OptionalEffectTiming*,
                    ExceptionState& = ASSERT_NO_EXCEPTION);
  AnimationTimeDelta GetCancelTime() const { return cancel_time_; }
  void SetCancelTime(AnimationTimeDelta cancel_time) {
    cancel_time_ = cancel_time;
  }

  // Attach/Detach the AnimationEffect from its owning animation.
  virtual void Attach(AnimationEffectOwner* owner) { owner_ = owner; }
  virtual void Detach() {
    DCHECK(owner_);
    owner_ = nullptr;
  }

  const Animation* GetAnimationForTesting() const { return GetAnimation(); }

  void Trace(Visitor*) const override;

 protected:
  explicit AnimationEffect(const Timing&, EventDelegate* = nullptr);

  // When AnimationEffect receives a new inherited time via updateInheritedTime
  // it will (if necessary) recalculate timings and (if necessary) call
  // updateChildrenAndEffects.
  void UpdateInheritedTime(base::Optional<AnimationTimeDelta> inherited_time,
                           base::Optional<TimelinePhase> inherited_phase,
                           TimingUpdateReason) const;
  void Invalidate() const { needs_update_ = true; }
  void InvalidateAndNotifyOwner() const;
  bool RequiresIterationEvents() const {
    return event_delegate_ && event_delegate_->RequiresIterationEvents(*this);
  }
  void ClearEventDelegate() { event_delegate_ = nullptr; }

  virtual void UpdateChildrenAndEffects() const = 0;

  // This is the value of the iteration duration when it is specified as 'auto'.
  // In web-animations-1, auto is treated as "the value zero for the purpose of
  // timing model calculations and for the result of the duration member
  // returned from getComputedTiming()".
  virtual AnimationTimeDelta IntrinsicIterationDuration() const {
    return AnimationTimeDelta();
  }

  virtual AnimationTimeDelta CalculateTimeToEffectChange(
      bool forwards,
      base::Optional<double> local_time,
      AnimationTimeDelta time_to_next_iteration) const = 0;

  const Animation* GetAnimation() const;
  Animation* GetAnimation();

  Member<AnimationEffectOwner> owner_;
  Timing timing_;
  Member<EventDelegate> event_delegate_;

  mutable Timing::CalculatedTiming calculated_;
  mutable bool needs_update_;
  mutable base::Optional<AnimationTimeDelta> last_update_time_;
  mutable base::Optional<Timing::Phase> last_update_phase_;
  AnimationTimeDelta cancel_time_;
  const Timing::CalculatedTiming& EnsureCalculated() const;
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_ANIMATION_ANIMATION_EFFECT_H_