/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * 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
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * 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
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef AnimationEffectReadOnly_h
#define AnimationEffectReadOnly_h

#include "core/CoreExport.h"
#include "core/animation/Timing.h"
#include "platform/bindings/ScriptWrappable.h"
#include "platform/heap/Handle.h"

namespace blink {

class Animation;
class AnimationEffectReadOnly;
class AnimationEffectTimingReadOnly;
class ComputedTimingProperties;

enum TimingUpdateReason {
  kTimingUpdateOnDemand,
  kTimingUpdateForAnimationFrame
};

static inline bool IsNull(double value) {
  return std::isnan(value);
}

static inline double NullValue() {
  return std::numeric_limits<double>::quiet_NaN();
}

// Represents the content of an Animation and its fractional timing state.
// http://w3c.github.io/web-animations/#animation-effect
class CORE_EXPORT AnimationEffectReadOnly
    : public GarbageCollectedFinalized<AnimationEffectReadOnly>,
      public ScriptWrappable {
  DEFINE_WRAPPERTYPEINFO();
  friend class Animation;  // Calls attach/detach, updateInheritedTime.
 public:
  // Note that logic in CSSAnimations depends on the order of these values.
  enum Phase {
    kPhaseBefore,
    kPhaseActive,
    kPhaseAfter,
    kPhaseNone,
  };

  class EventDelegate : public GarbageCollectedFinalized<EventDelegate> {
   public:
    virtual ~EventDelegate() {}
    virtual bool RequiresIterationEvents(const AnimationEffectReadOnly&) = 0;
    virtual void OnEventCondition(const AnimationEffectReadOnly&) = 0;
    DEFINE_INLINE_VIRTUAL_TRACE() {}
  };

  virtual ~AnimationEffectReadOnly() {}

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

  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; }
  double CurrentIteration() const {
    return EnsureCalculated().current_iteration;
  }
  double Progress() const { return EnsureCalculated().progress; }
  double TimeToForwardsEffectChange() const {
    return EnsureCalculated().time_to_forwards_effect_change;
  }
  double TimeToReverseEffectChange() const {
    return EnsureCalculated().time_to_reverse_effect_change;
  }

  double IterationDuration() const;
  double ActiveDurationInternal() const;
  double EndTimeInternal() const {
    return SpecifiedTiming().start_delay + ActiveDurationInternal() +
           SpecifiedTiming().end_delay;
  }

  const Animation* GetAnimation() const { return animation_; }
  Animation* GetAnimation() { return animation_; }
  const Timing& SpecifiedTiming() const { return timing_; }
  virtual AnimationEffectTimingReadOnly* timing();
  void UpdateSpecifiedTiming(const Timing&);

  void getComputedTiming(ComputedTimingProperties&);
  ComputedTimingProperties getComputedTiming();

  DECLARE_VIRTUAL_TRACE();

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

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

  virtual void Attach(Animation* animation) { animation_ = animation; }

  virtual void Detach() {
    DCHECK(animation_);
    animation_ = nullptr;
  }

  double RepeatedDuration() const;

  virtual void UpdateChildrenAndEffects() const = 0;
  virtual double IntrinsicIterationDuration() const { return 0; }
  virtual double CalculateTimeToEffectChange(
      bool forwards,
      double local_time,
      double time_to_next_iteration) const = 0;
  virtual void SpecifiedTimingChanged() {}

  Member<Animation> animation_;
  Timing timing_;
  Member<EventDelegate> event_delegate_;

  mutable struct CalculatedTiming {
    DISALLOW_NEW();
    Phase phase;
    double current_iteration;
    double progress;
    bool is_current;
    bool is_in_effect;
    bool is_in_play;
    double local_time;
    double time_to_forwards_effect_change;
    double time_to_reverse_effect_change;
  } calculated_;
  mutable bool needs_update_;
  mutable double last_update_time_;
  String name_;

  const CalculatedTiming& EnsureCalculated() const;
};

}  // namespace blink

#endif  // AnimationEffectReadOnly_h
