Extra2D/include/animation/tween.h

#pragma once

#include <animation/tween_easing.h>
#include <core/color.h>
#include <core/math_types.h>
#include <functional>
#include <initializer_list>
#include <memory>
#include <optional>
#include <string>
#include <vector>

namespace extra2d {

class Node;

struct TweenOptions {
  TweenEasing easing = TweenEasing::Linear;
  std::function<void()> onStart = nullptr;
  std::function<void(float progress)> onUpdate = nullptr;
  std::function<void()> onComplete = nullptr;
};

struct TweenProperty {
  std::optional<Vec2> position;
  std::optional<Vec2> scale;
  std::optional<float> rotation;
  std::optional<float> opacity;
  std::optional<Color> color;
};

class TweenAction {
public:
  enum class Type : uint8_t {
    Interval,
    Delay,
    Call,
    Parallel,
  };

  virtual ~TweenAction() = default;
  virtual void update(float dt) = 0;
  virtual bool isFinished() const = 0;
  virtual float getDuration() const = 0;
  virtual float getElapsed() const = 0;
  virtual void reset() = 0;

  Type getType() const { return type_; }

protected:
  TweenAction(Type type) : type_(type) {}
  Type type_;
};

class Tween {
public:
  using Ptr = std::shared_ptr<Tween>;
  using Callback = std::function<void()>;

  explicit Tween(Node *target);
  Tween(Node *target, const std::string &name);
  ~Tween();

  Tween(const Tween &) = delete;
  Tween &operator=(const Tween &) = delete;
  Tween(Tween &&) = default;
  Tween &operator=(Tween &&) = default;

  static Tween create(Node *target);
  static Tween create(Node *target, const std::string &name);

  Tween &to(float duration, const TweenProperty &props,
            const TweenOptions &options = {});
  Tween &by(float duration, const TweenProperty &props,
            const TweenOptions &options = {});

  Tween &set(const TweenProperty &props);
  Tween &delay(float seconds);
  Tween &call(Callback callback);

  Tween &parallel();
  Tween &endParallel();

  Tween &union_();
  Tween &repeat(int times);
  Tween &repeatForever();
  Tween &yoyo(bool enabled = true);

  void start();
  void stop();
  void pause();
  void resume();

  void update(float dt);

  bool isFinished() const;
  bool isPlaying() const;
  bool isPaused() const;
  float getTotalDuration() const;

  void setName(const std::string &name) { name_ = name; }
  const std::string &getName() const { return name_; }

private:
  Node *target_ = nullptr;
  std::string name_;
  std::vector<std::unique_ptr<TweenAction>> actions_;
  size_t currentActionIndex_ = 0;

  bool playing_ = false;
  bool paused_ = false;
  bool finished_ = false;

  int repeatCount_ = 1;
  int currentRepeat_ = 0;
  bool yoyo_ = false;
  bool reverse_ = false;
  bool repeatForever_ = false;

  bool inParallel_ = false;
  std::vector<std::unique_ptr<TweenAction>> parallelActions_;

  void addAction(std::unique_ptr<TweenAction> action);
  void advanceToNextAction();
  void resetAllActions();
};

namespace tween {

inline TweenProperty pos(const Vec2 &p) {
  TweenProperty props;
  props.position = p;
  return props;
}

inline TweenProperty pos(float x, float y) { return pos(Vec2(x, y)); }

inline TweenProperty scl(const Vec2 &s) {
  TweenProperty props;
  props.scale = s;
  return props;
}

inline TweenProperty scl(float s) { return scl(Vec2(s, s)); }

inline TweenProperty rot(float degrees) {
  TweenProperty props;
  props.rotation = degrees;
  return props;
}

inline TweenProperty opa(float opacity) {
  TweenProperty props;
  props.opacity = opacity;
  return props;
}

inline TweenProperty col(const Color &c) {
  TweenProperty props;
  props.color = c;
  return props;
}

TweenProperty combine(std::initializer_list<TweenProperty> props);

} // namespace tween

} // namespace extra2d