#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <HX711_ADC.h>

const int buttonPin = 2;
int buttonState = HIGH;
int lastState = LOW;
unsigned long lastTime = 0;
unsigned long BounceDelay = 50;

bool tared = false;

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

//pins:
const int HX711_dout = 4; //mcu > HX711 dout pin
const int HX711_sck = 5; //mcu > HX711 sck pin

//HX711 constructor:
HX711_ADC LoadCell(HX711_dout, HX711_sck);

const int calVal_calVal_eepromAdress = 0;
unsigned long t = 0;


void setup() {
  Serial.begin(115200);

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  delay(2000);
  display.clearDisplay();
  display.setTextColor(WHITE);
 


  float calibrationValue; // calibration value
  calibrationValue = 21.28;

  LoadCell.begin();
  unsigned long stabilizingtime = 2000; // tare preciscion can be improved by adding a few seconds of stabilizing time
  boolean _tare = false; //set this to false if you don't want tare to be performed in the next step
  LoadCell.start(stabilizingtime, _tare);
  if (LoadCell.getTareTimeoutFlag()) {
    Serial.println("Timeout, check MCU>HX711 wiring and pin designations");
  }
  else {
    LoadCell.setCalFactor(calibrationValue); // set calibration factor (float)
    Serial.println("Startup is complete");
  }
  LoadCell.tareNoDelay();
  delay(1000);
}

void loop() {

  tareCheck();

  static boolean newDataReady = 0;
  const int serialPrintInterval = 500; //increase value to slow down serial print activity

  // check for new data/start next conversion:
  if (LoadCell.update()) newDataReady = true;

  // get smoothed value from the dataset:
  if (newDataReady) {
    if (millis() > t + serialPrintInterval) {
      float i = LoadCell.getData();
      if(tared){
        tared = false;
        i = 0;
      }
      Serial.print("Load_cell output val: ");
      Serial.println(i);
      if(i < 0) i = 0;
      i *= 100;
      if(int(i)%100 > 50)  i = ceil(i/100);
      else i = floor(i/100);
      newDataReady = 0;
      t = millis();
      //clear display
      display.clearDisplay();
   
      // display weight
      display.setTextSize(1);
      display.setCursor(0,0);
      display.print("Weight: ");
      display.setTextSize(4);
      display.setCursor(0,8);
      display.print(int(i));
      display.print(" ");
      display.setTextSize(4);
      display.print("g");
     
     
     
      display.display();
    }
  }
}
void tareCheck(){
  int reading = digitalRead(buttonPin);
 
  if(reading != lastState) lastTime = millis();
  if((millis() - lastTime) > BounceDelay){
    if(reading != buttonState)
    buttonState = reading;
    if(buttonState==HIGH){
      tared = true;
      display.clearDisplay();
      display.setTextSize(2);
      display.setCursor(0,0);
      display.print("Taring...");
      display.display();
      delay(5000);
      LoadCell.tareNoDelay();
     
    }
  }
  lastState = reading;
}