#include <HX711.h>
#include <Servo.h>

HX711 scale;
Servo servo;

int dispense_button = 0;

void setup() {
  servo.attach(9);
  servo.write(90);
  Serial.begin(9600);
  scale.begin(A1, A0);
  scale.wait_ready();
  delay(500); // seems to give initial false reading otherwise
}

float map_float(
  float x, float in_min, float in_max, float out_min, float out_max
) {
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

int SAMPLES = 10;
int MAX_READING = 1890;
float EMPTY_THRESHOLD = 0.5f;
float REFILL_THRESHOLD = 1.5f;

float read_weight(HX711 scale) {
  return map_float(scale.get_units(SAMPLES), 0, MAX_READING, 0, 5);
}

void loop() {
  if (read_weight(scale) < EMPTY_THRESHOLD) {
      servo.write(0);
      while (read_weight(scale) < REFILL_THRESHOLD) {
        delay(100);
      }
  }

  while (digitalRead(dispense_button) == LOW) {
    servo.write(0);
    delay(100);
  }
  servo.write(90);
  delay(100);
}