/*
 * Copyright 2016 Google Inc. 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_BROWSER_WEB_MODULE_STAT_TRACKER_H_
#define COBALT_BROWSER_WEB_MODULE_STAT_TRACKER_H_

#include <string>
#include <vector>

#include "base/memory/scoped_vector.h"
#include "cobalt/base/c_val.h"
#include "cobalt/base/stop_watch.h"
#include "cobalt/dom/dom_stat_tracker.h"
#include "cobalt/dom/event.h"
#include "cobalt/layout/layout_stat_tracker.h"

namespace cobalt {
namespace browser {

// This class handles tracking web module stats and is intended for single
// thread use. It also owns the |DomStatTracker| and |LayoutStatTracker|.
class WebModuleStatTracker : public base::StopWatchOwner {
 public:
  WebModuleStatTracker(const std::string& name,
                       bool should_track_injected_events);
  ~WebModuleStatTracker();

  dom::DomStatTracker* dom_stat_tracker() const {
    return dom_stat_tracker_.get();
  }

  layout::LayoutStatTracker* layout_stat_tracker() const {
    return layout_stat_tracker_.get();
  }

  // |OnInjectEvent| starts event stat tracking if
  // |should_track_injected_events_| is true. Otherwise, it does nothing.
  void OnInjectEvent(const scoped_refptr<dom::Event>& event);

  // |OnRenderTreeProduced| ends stat tracking for the current event and also
  // triggers flushing of periodic counts within the stat trackers.
  void OnRenderTreeProduced();

 private:
  enum EventType {
    kEventTypeInvalid = -1,
    kEventTypeKeyDown,
    kEventTypeKeyUp,
    kNumEventTypes,
  };

  enum StopWatchType {
    kStopWatchTypeEvent,
    kNumStopWatchTypes,
  };

  struct EventStats {
    explicit EventStats(const std::string& name);

    // Count-related
    base::CVal<int, base::CValPublic> count_dom_html_elements_created;
    base::CVal<int, base::CValPublic> count_dom_html_elements_destroyed;
    base::CVal<int, base::CValPublic> count_dom_update_matching_rules;
    base::CVal<int, base::CValPublic> count_dom_update_computed_style;
    base::CVal<int, base::CValPublic> count_layout_boxes_created;
    base::CVal<int, base::CValPublic> count_layout_boxes_destroyed;

    // Duration-related
    base::CVal<base::TimeDelta, base::CValPublic> duration_total;
    base::CVal<base::TimeDelta, base::CValPublic> duration_dom_inject_event;
    base::CVal<base::TimeDelta, base::CValPublic>
        duration_dom_update_computed_style;
    base::CVal<base::TimeDelta, base::CValPublic> duration_layout_box_tree;
    base::CVal<base::TimeDelta, base::CValPublic>
        duration_layout_box_generation;
    base::CVal<base::TimeDelta, base::CValPublic>
        duration_layout_update_used_sizes;
    base::CVal<base::TimeDelta, base::CValPublic>
        duration_layout_render_and_animate;
  };

  // From base::StopWatchOwner
  bool IsStopWatchEnabled(int id) const OVERRIDE;
  void OnStopWatchStopped(int id, base::TimeDelta time_elapsed) OVERRIDE;

  // End the current event if one is active. This triggers an update of all
  // |EventStats| for the event.
  void EndCurrentEvent(bool was_render_tree_produced);

  static std::string GetEventTypeName(EventType event_type);

  // Web module owns the dom and layout stat trackers.
  scoped_ptr<dom::DomStatTracker> dom_stat_tracker_;
  scoped_ptr<layout::LayoutStatTracker> layout_stat_tracker_;

  // Event-related
  const bool should_track_event_stats_;
  EventType current_event_type_;
  // Each individual |EventType| has its own entry in the vector.
  ScopedVector<EventStats> event_stats_;

  // Stop watch-related
  std::vector<base::StopWatch> stop_watches_;
  std::vector<base::TimeDelta> stop_watch_durations_;

  std::string name_;

  base::CVal<int, base::CValPublic> event_is_processing_;
};

}  // namespace browser
}  // namespace cobalt

#endif  // COBALT_BROWSER_WEB_MODULE_STAT_TRACKER_H_