#ifndef EFFECT_SYSTEM_H_0B497B39
#define EFFECT_SYSTEM_H_0B497B39

#include "system.h"
#include "timer.h"
#include "vector.h"

class Game;

class EffectSystem : public System {
public:

  static constexpr SystemKey Key = SystemKey::Effect;

  explicit EffectSystem(Game& game) : game_(game) {}

  void tick(double dt) override;

  /* Commands */

  // Fades the entire screen in or out
  // - length is in milliseconds
  // - amount is [0,1]
  void fadeScreen(int length, double amount);

  // Fades just the map, leaving the sprites, messages, etc unfaded.
  // - length is in milliseconds
  // - amount is [0,1]
  void fadeMap(int length, double amount);

  // Shakes the viewport by 1 tile in both directions.
  // - period is in milliseconds, it's actually a half period
  void shakeCamera(int period);

  void stopShakingCamera();

  /* Information */

  bool isScreenFaded() const { return screenFade_ > 0.0; }

  double getScreenFadeProgress() const { return screenFade_; }

  bool isScreenFadeComplete() const { return screenFade_ == screenFadeDest_; }

  bool isMapFaded() const { return mapFade_ > 0.0; }

  double getMapFadeProgress() const { return mapFade_; }

  bool isMapFadeComplete() const { return mapFade_ == mapFadeDest_; }

  const vec2i& getCameraShakeOffset() const { return cameraShakeOffset_; }

  bool isCameraShaking() const { return cameraShaking_; }

private:

  Game& game_;

  double screenFade_ = 0.0;
  double screenFadeDest_ = 0.0;
  double screenFadeStart_ = 0.0;
  double screenFadeLength_ = 0;
  double screenFadeThus_ = 0;

  double mapFade_ = 0.0;
  double mapFadeDest_ = 0.0;
  double mapFadeStart_ = 0.0;
  double mapFadeLength_ = 0.0;
  double mapFadeThus_ = 0.0;

  bool cameraShaking_ = false;
  vec2i cameraShakeOffset_ { 0, 0 };
  bool cameraShakeOn_ = false;
  Timer cameraShakeTimer_ { 0 };
};

#endif /* end of include guard: EFFECT_SYSTEM_H_0B497B39 */