#include <DHT.h>

// ====== Sensor Setup ======
#define DHTPIN 4       // GPIO pin connected to DHT sensor
#define DHTTYPE DHT22  // Change to DHT11 if using that model
DHT dht(DHTPIN, DHTTYPE);

// ====== State Machine ======
enum State {
    Idle,
    Heating,
    Stabilizing,
    TargetReached,
    Overheat
};

State currentState = Idle;

// ====== Configurable Parameters ======
float targetTemp = 30.0;      // Target temperature in °C
float overheatTemp = 40.0;    // Overheat threshold in °C
float tolerance = 1.0;        // Allowed variation

void setup() {
    Serial.begin(115200);
    dht.begin();
    Serial.println("Temperature State Tracker Started");
}

void loop() {
    float temp = dht.readTemperature(); // Read temperature in °C

    if (isnan(temp)) {
        Serial.println("Failed to read from DHT sensor!");
        delay(2000);
        return;
    }

    // ===== State Transitions =====
    switch (currentState) {
        case Idle:
            if (temp < targetTemp - tolerance)
                currentState = Heating;
            break;

        case Heating:
            if (temp >= targetTemp - tolerance)
                currentState = Stabilizing;
            else if (temp > overheatTemp)
                currentState = Overheat;
            break;

        case Stabilizing:
            if (fabs(temp - targetTemp) <= tolerance)
                currentState = TargetReached;
            else if (temp > overheatTemp)
                currentState = Overheat;
            else if (temp < targetTemp - tolerance)
                currentState = Heating;
            break;

        case TargetReached:
            if (temp > overheatTemp)
                currentState = Overheat;
            else if (temp < targetTemp - tolerance)
                currentState = Heating;
            break;

        case Overheat:
            if (temp <= targetTemp)
                currentState = Stabilizing;
            break;
    }

    // ===== Output =====
    Serial.print("Temperature: ");
    Serial.print(temp);
    Serial.print(" °C -> State: ");
    Serial.println(getStateName(currentState));

    delay(2000); // Wait 2 seconds before next reading
}

// ===== Helper Function =====
String getStateName(State s) {
    switch (s) {
        case Idle: return "Idle";
        case Heating: return "Heating";
        case Stabilizing: return "Stabilizing";
        case TargetReached: return "Target Reached";
        case Overheat: return "Overheat";
    }
    return "Unknown";
}