#include <MAX6675.h>
#include <LiquidCrystal_I2C.h>

// MAX6675 Pins
int thermoDO = 4;
int thermoCS = 5;
int thermoCLK = 6;

// Control Pins
int triacPin = 9;
int potPin = A0;      // Potentiometer

// 10 Temperature Levels (0-200°C)
int tempLevels[11] = {0, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200};
int currentLevel = 0;
float currentTemp = 0;
int powerLevel = 0;
unsigned long previousBlinkTime = 0;
bool blinkState = false;

MAX6675 thermocouple(thermoCLK, thermoCS, thermoDO);
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  pinMode(triacPin, OUTPUT);
  pinMode(potPin, INPUT);
  
  lcd.init();
  lcd.backlight();
  lcd.print("Temp Controller");
  lcd.setCursor(0, 1);
  lcd.print("0-200C 10 Levels");
  delay(2000);
  
  Serial.begin(9600);
}

void loop() {
  // Read temperature
  currentTemp = thermocouple.readCelsius();
  
  // Read potentiometer and select level 0-10
  int potValue = analogRead(potPin);
  currentLevel = map(potValue, 0, 1023, 0, 10);
  
  int setpoint = tempLevels[currentLevel];
  
  // Calculate power based on temperature difference
  powerLevel = calculateStepPower(currentTemp, setpoint);
  
  // Safety cutoff at 200°C
  if (currentTemp >= 200) {
    powerLevel = 0;
    digitalWrite(triacPin, LOW);
  }
  
  // Apply power to triac
  analogWrite(triacPin, powerLevel);
  
  // Display information with blinking ON
  displayStatus(currentTemp, powerLevel, currentLevel);
  
  delay(500);
}

int calculateStepPower(float current, int target) {
  int power = 0;
  float diff = target - current;
  
  if (current >= 200) return 0;
  
  if (target == 0) {
    power = 0;
  }
  else if (diff > 20) {
    power = 255;
  }
  else if (diff > 10) {
    power = 200;
  }
  else if (diff > 5) {
    power = 150;
  }
  else if (diff > 2) {
    power = 100;
  }
  else if (diff > 0) {
    power = 50;
  }
  else {
    power = 0;
  }
  
  return power;
}

void displayStatus(float current, int power, int level) {
  // Blink logic for ON text (500ms interval)
  if (millis() - previousBlinkTime > 500) {
    blinkState = !blinkState;
    previousBlinkTime = millis();
  }
  
  lcd.clear();
  
  // Row 1: Power:ON/OFF Temp:(current temperature)*C
  lcd.setCursor(0, 0);
  lcd.print("Power:");
  
  if (power > 0) {
    // Blinking ON
    if (blinkState) {
      lcd.print("ON ");
    } else {
      lcd.print("   "); // Blank when off
    }
  } else {
    // Steady OFF
    lcd.print("OFF");
  }
  
  lcd.setCursor(10, 0);
  lcd.print("T:");
  lcd.print(current, 1);
  lcd.print("*C");
  
  // Row 2: Level=0-10
  lcd.setCursor(0, 1);
  lcd.print("Level=");
  lcd.print(level);
  
  // Serial Monitor output
  Serial.print("Pot Value: ");
  Serial.print(analogRead(potPin));
  Serial.print(" | Level: ");
  Serial.print(level);
  Serial.print(" | Set: ");
  Serial.print(tempLevels[level]);
  Serial.print("C | Temp: ");
  Serial.print(current, 1);
  Serial.print("C | Power: ");
  Serial.println(power > 0 ? "ON" : "OFF");
}