#include <Wire.h>
#include <Keypad.h>
#include <LiquidCrystal_I2C.h>
#include <HX711.h>

//LCD FUNCTION
LiquidCrystal_I2C lcd(0x27,16,2);

//KEYPAD FUNCTION
const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
//define the cymbols on the buttons of the keypads
char hexaKeys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'.','0','#','D'}
};

byte rowPins[ROWS] = {9, 8, 7, 6}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {5, 4, 3, 2}; //connect to the column pinouts of the keypad

//initialize an instance of class NewKeypad
Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS); 

//LOAD CELL FUNCTION
const int LOADCELL_DOUT_PIN = 11;
const int LOADCELL_SCK_PIN = 12;
HX711 scale;

//GLOBAL VARIABLE
static String Action = "nothing";
static float CalibrationFactor;
static String keypadinput = "";
static float TargetWeight = 0.00;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0,0);
  lcd.println("AUTOMATIC WEIGHT");
  lcd.setCursor(0,1);
  lcd.println("   DISPENSER");
  delay(2000);
  lcd.clear();

  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
  scale.set_scale(CalibrationFactor);
  scale.tare();
  
}

void calibrate(){
  if (Action == "nothing")
  {
    Action = "calibrate_1";
    keypadinput = "";
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.println("==CALIBRATION==");
    delay(3000);
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.println("Remove weight");
    lcd.setCursor(0,1);
    lcd.println("then press Enter");
    return;
  }

  if (Action == "calibrate_1")
  {
    if (scale.is_ready())
    {
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.println("Calculating");
      lcd.setCursor(0,1);
      lcd.println("Please wait..");
      delay(2000);
      scale.tare();
      scale.set_scale(0);
      CalibrationFactor = 0;
      CalibrationFactor = scale.get_units(10);
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.print("Weight:0");
      lcd.setCursor(0,1);
      lcd.print("CF:");
      lcd.print(String(CalibrationFactor));
      delay(2000);
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.println("Place weight");
      lcd.setCursor(0,1);
      lcd.println("then press Enter");
      Action = "calibrate_2";
    }
    else
    {
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.println("Scale not found");
      lcd.setCursor(0,1);
      lcd.println("Calibrate failed");
      Action == "false";
      delay(3000);
    }
    return;
  }

  if (Action == "calibrate_2")
  {
    if (scale.is_ready())
    {
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.println("Weight (gr):");
      lcd.setCursor(0,1);
      Action = "calibrate_3";
    }
    else
    {
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.println("Scale not found");
      lcd.setCursor(0,1);
      lcd.println("Calibrate failed");
      Action == "nothing";
      delay(3000);
    }
  return;
  }

  if(Action == "calibrate_3")
  {
    lcd.clear();
    CalibrationFactor = CalibrationFactor + scale.get_units(10);
    CalibrationFactor = CalibrationFactor / keypadinput.toFloat();
    scale.set_scale(CalibrationFactor);
    lcd.setCursor(0,0);
    lcd.print("Weight:");
    lcd.print(keypadinput);
    lcd.setCursor(0,1);
    lcd.print("CF:");
    lcd.print(String(CalibrationFactor));
    delay(2000);
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.println("Calibration");
    lcd.setCursor(0,1);
    lcd.println("Success!");
    Action = "nothing";
    delay(2000);
    lcd.clear();
    return;
  }
}

void scale_func(){
  if(Action == "nothing"){
    float weight = scale.get_units(10);

    lcd.setCursor(0,0);
    lcd.print("Weight:");
    lcd.print(weight,1);
    lcd.println("gr");
    lcd.setCursor(0,1);
    lcd.print("Set to:");
    delay(100);
  }
}

void setTargetWeight(){
  if(Action == "nothing"){
    keypadinput = "";
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Set Weight (gr):");
    lcd.setCursor(0,1);
    Action = "set_target";
    return;
  }

  if(Action == "set_target"){
    TargetWeight = keypadinput.toFloat();
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Done");
    lcd.setCursor(0,1);
    lcd.print("Set to:");
    lcd.print(TargetWeight,1);
    lcd.print("gr");
    Action = "nothing";
    delay(1000);
    return;
  }  
}

void loop() {
  // put your main code here, to run repeatedly:
  char customKey = customKeypad.getKey();
  
  if(customKey != NO_KEY)
  {
    if (isdigit(customKey)){
      lcd.print(String(customKey));
      keypadinput = keypadinput + String(customKey);
    }
    if(customKey == 'A'){
      Action = "nothing";
      calibrate();
    }
    if(customKey == 'B'){
      Action = "nothing";
      scale.tare();
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.println("Weight:0.0gr");
    }
    if(customKey == 'C'){
      setTargetWeight();
    }
    if(customKey == 'D'){

      if(Action == "calibrate_1" or Action == "calibrate_2" or Action == "calibrate_3"){
        calibrate();
      }
      if(Action == "set_target"){
        setTargetWeight();
      }
    }
    if(customKey == '.'){
      
    }
    if(customKey == '#'){
      
    }
  } else
  {
    scale_func();
  }
}