// Copyright 2015 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef COBALT_CSSOM_ANIMATION_SET_H_
#define COBALT_CSSOM_ANIMATION_SET_H_

#include <map>
#include <string>
#include <utility>

#include "cobalt/cssom/animation.h"
#include "cobalt/cssom/css_computed_style_data.h"

namespace cobalt {
namespace cssom {

// Manages a set of CSS Animation instantiations applied to a specific
// element (either an HTML Element or a Pseudo Element).  The
// AnimationSet::Update() method should be called to update the AnimationSet's
// internal animations based on the new computed style.  As AnimationSet
// internally creates and destroys a set of animations, it generates
// EventHandler::OnAnimationStarted() and EventHandler::OnAnimationRemoved()
// events.
class AnimationSet {
 public:
  class EventHandler {
   public:
    virtual void OnAnimationStarted(const Animation& animation,
                                    AnimationSet* animation_set) = 0;
    virtual void OnAnimationEnded(const Animation& animation) = 0;
    virtual void OnAnimationRemoved(const Animation& animation) = 0;
  };

  // Create an Animation with the specified EventHandler, whose methods will
  // be called when Animation::Update() is called.
  explicit AnimationSet(EventHandler* event_handler);

  // Update the internal state of animations based on our previous state and the
  // passed in computed style.  Animations may be started or ended when this
  // method is called.
  // Returns whether or not the update modified the animations.
  bool Update(const base::TimeDelta& current_time,
              const CSSComputedStyleData& style,
              const CSSKeyframesRule::NameMap& keyframes_map);

  // Returns true if there are no animations in this set.
  bool empty() const { return animations_.empty(); }

  // Clears all animations out of this animation set.
  void Clear();

 private:
  // Our internal collection of animations, mapping 'animation-name' to
  // a Animation object.
  struct AnimationEntry {
    explicit AnimationEntry(Animation&& in_animation)
        : animation(std::move(in_animation)) {}
    Animation animation;
    bool ended = false;
  };
  typedef std::map<std::string, AnimationEntry> InternalAnimationMap;

  EventHandler* event_handler_;
  InternalAnimationMap animations_;

  DISALLOW_COPY_AND_ASSIGN(AnimationSet);
};

}  // namespace cssom
}  // namespace cobalt

#endif  // COBALT_CSSOM_ANIMATION_SET_H_