#include "DHT.h"

#define DHTPIN 4
#define DHTTYPE DHT22
#define HEATER_PIN 5

DHT dht(DHTPIN, DHTTYPE);

float targetTemp = 60.0;
float overheatTemp = 80.0;
float stabilizingRange = 2.0;

enum State { IDLE, HEATING, STABILIZING, TARGET_REACHED, OVERHEAT };
State currentState = IDLE;

void setup() {
  Serial.begin(115200);
  dht.begin();
  pinMode(HEATER_PIN, OUTPUT);
  digitalWrite(HEATER_PIN, LOW);
}

void loop() {
  float temp = dht.readTemperature();
  if (isnan(temp)) {
    Serial.println("Error reading temperature!");
    delay(1000);
    return;
  }

  switch (currentState) {
    case IDLE:
      if (temp < targetTemp - stabilizingRange) {
        currentState = HEATING;
        digitalWrite(HEATER_PIN, HIGH);
      }
      break;

    case HEATING:
      if (temp >= targetTemp - stabilizingRange) {
        currentState = STABILIZING;
      }
      break;

    case STABILIZING:
      if (temp >= targetTemp && temp < overheatTemp) {
        currentState = TARGET_REACHED;
        digitalWrite(HEATER_PIN, LOW);
      } else if (temp >= overheatTemp) {
        currentState = OVERHEAT;
      }
      break;

    case TARGET_REACHED:
      if (temp < targetTemp - stabilizingRange) {
        currentState = HEATING;
        digitalWrite(HEATER_PIN, HIGH);
      }
      break;

    case OVERHEAT:
      digitalWrite(HEATER_PIN, LOW);
      Serial.println("OVERHEAT! Heater OFF!");
      break;
  }

  Serial.print("Temp: ");
  Serial.print(temp);
  Serial.print(" °C | State: ");
  Serial.println(stateToString(currentState));

  delay(1000);
}

String stateToString(State s) {
  switch(s) {
    case IDLE: return "IDLE";
    case HEATING: return "HEATING";
    case STABILIZING: return "STABILIZING";
    case TARGET_REACHED: return "TARGET_REACHED";
    case OVERHEAT: return "OVERHEAT";
  }
  return "";
}