//LCD config
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);

//Thermistor needed libraries
#include <thermistor.h>
thermistor therm1(A0, 0);

//I/O
int PWM_pin = 5;         //Pin for PWM signal to the MOSFET driver (the BJT npn with pullup)
int speed_pot = A1;
int temp_pot = A2;
int LED = 13;

//Variables
float set_temperature = 200;    //Default temperature setpoint. Leave it 0 and control it with rotary encoder
float temperature_read = 0.0;
float PID_error = 0;
float previous_error = 0;
float elapsedTime, Time, timePrev;
float PID_value = 0;
float rotating_speed = 0;

#include <AccelStepper.h>
AccelStepper stepper1(1, 3, 4);  //(Type of driver: with 2 pins, STEP, DIR)

//PID constants
int kp = 90;
int ki = 30;
int kd = 80;

int PID_p = 0;
int PID_i = 0;
int PID_d = 0;

int max_PWM = 255;
int max_speed = 500;

void setup() {
  pinMode(LED, OUTPUT);
  digitalWrite(LED, LOW);

  pinMode(PWM_pin, OUTPUT);
  TCCR0B = TCCR0B & B11111000 | B00000010;    // D6 adn D6 PWM frequency of 7812.50 Hz
  Time = millis();

  TCCR1A = 0;       //Reset entire TCCR1A register
  TCCR1B = 0;       //Reset entire TCCR1B register
  TCCR1A |= B00000010;  // /8
  TCNT1 = 0;        //Reset Timer 1 value to 0

  lcd.init();
  lcd.backlight();
  
  }

void loop() {
  // Reading the real value of temperature
  temperature_read = therm1.analog2temp(); // read temperature
  set_temperature = map(analogRead(temp_pot), 0, 1023, 0, 300); // Adjust the range as needed

  // Calculating the error between the setpoint and the real value
  PID_error = set_temperature - temperature_read + 6;
  // Calculate the P value
  PID_p = 0.01 * kp * PID_error;
  // Calculate the I value in a range on +-6
  PID_i = 0.01 * PID_i + (ki * PID_error);

  // For derivative we need real time to calculate speed change rate
  timePrev = Time;                            // the previous time is stored before the actual time read
  Time = millis();                            // actual time read
  elapsedTime = (Time - timePrev) / 1000;
  // Now we can calculate the D value
  PID_d = 0.01 * kd * ((PID_error - previous_error) / elapsedTime);
  // Final total PID value is the sum of P + I + D
  PID_value = PID_p + PID_i + PID_d;

  // We define PWM range between 0 and 255
  if (PID_value < 0) {
    PID_value = 0;
  }
  if (PID_value > max_PWM) {
    PID_value = max_PWM;
  }

  // Now we can write the PWM signal to the mosfet on digital pin D5
  analogWrite(PWM_pin, PID_value);
  previous_error = PID_error;

 // Running the stepper motor at the calculated speed
  digitalWrite(LED, HIGH);
    // Calculating rotating speed based on potentiometer value
 int potValue = analogRead(speed_pot);
  Serial.print("Potentiometer Value: ");
  Serial.println(potValue);

  int rotating_speed = map(potValue, 0, 1024, 0, 4000);
  Serial.print("Rotating Speed: ");
  Serial.println(rotating_speed);

  stepper1.setMaxSpeed(rotating_speed);
  stepper1.moveTo(10000); // Set a long distance to move to
  stepper1.run(); // This will run the motor continuously at the set speed

  delay(250); //Refresh rate + delay of LCD print


  // Displaying temperature and speed on LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("T: ");
  lcd.print(temperature_read, 1);
  lcd.print(" S: ");
  lcd.print(rotating_speed);

  lcd.setCursor(0, 1);
  lcd.print("PID: ");
  lcd.print(PID_value);

}