A traffic light simulator for an arduino uno

traffic.ino

typedef enum {
  Pedestrian,
  Traffic
} LightType;

typedef struct {
  int lights[2];
  int phase;
} PedestrianLights;

typedef struct {
  int lights[3];
  PedestrianLights *pedestrian_lights;
  int phase;
} TrafficLights;

typedef struct {
  LightType type;
  void *content;
} Lights;

void set_phase(Lights lights, int phase) {
  if (lights.type == Pedestrian) {
    PedestrianLights *content = lights.content;
    
    content->phase = phase;

    if (!phase) {
      digitalWrite(content->lights[0], HIGH);
      digitalWrite(content->lights[1], LOW);
    } else if (phase) {
      digitalWrite(content->lights[0], LOW);
      digitalWrite(content->lights[1], HIGH);
    }
  } else if (lights.type == Traffic) {
    TrafficLights *content = lights.content;

    content->phase = phase;

    if (!phase) {
      digitalWrite(content->lights[0], HIGH);
      digitalWrite(content->lights[1], LOW);
      digitalWrite(content->lights[2], LOW);
    } else if (phase == 1) {
      digitalWrite(content->lights[0], HIGH);
      digitalWrite(content->lights[1], HIGH);
      digitalWrite(content->lights[2], LOW);
    } else if (phase == 2) {
      digitalWrite(content->lights[0], LOW);
      digitalWrite(content->lights[1], LOW);
      digitalWrite(content->lights[2], HIGH);
    } else if (phase == 3) {
      digitalWrite(content->lights[0], LOW);
      digitalWrite(content->lights[1], HIGH);
      digitalWrite(content->lights[2], LOW);
    }
  }
}

void next_phase(Lights lights) {
  if (lights.type == Pedestrian) {
    PedestrianLights *content = lights.content;
    set_phase(lights, !content->phase);
  } else if (lights.type == Traffic) {
    TrafficLights *content = lights.content;

    int phase = content->phase + 1;
    if (phase > 3) phase = 0;

    set_phase(lights, phase);
  }
}

PedestrianLights first_p_content;
Lights first_p;

TrafficLights first_t_content;
Lights first_t;

void setup() {
  first_p_content = {
    .lights = {13, 12},
    .phase = 0
  };

  first_p = {
    .type = Pedestrian,
    .content = (void *)&first_p_content
  };

  first_t_content = {
    .lights = {9, 10, 11},
    .pedestrian_lights = &first_p_content,
    .phase = 0
  };

  first_t = {
    .type = Traffic,
    .content = (void *)&first_t_content
  };

  pinMode(13, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(9, OUTPUT);

  //set_phase(first_p, 0);
  set_phase(first_t, 0); 
}

void loop() {
  //next_phase(first_p);
  delay(1000);
  next_phase(first_t);
}