#include <math.h>

const int NTC_PIN = A0;
const float VREF = 5.0;
const float ADC_MAX = 1023.0;
const float FIXED_RESISTOR = 10000.0;
const float R0 = 10000.0;
const float T0_K = 298.15;
const float BETA = 3950.0;

const unsigned long SAMPLE_INTERVAL_MS = 1000;
unsigned long lastSampleTime = 0;

const char* getStatus(float temperatureC) {
  if (temperatureC >= 50.0) {
    return "FAIL";
  } else if (temperatureC >= 40.0) {
    return "WARN";
  } else {
    return "NORMAL";
  }
}

void setup() {
  Serial.begin(9600);
  Serial.println("time_ms,adc_value,voltage,resistance_ohms,temperature_c,status");
}

void loop() {
  unsigned long now = millis();

  if (now - lastSampleTime >= SAMPLE_INTERVAL_MS) {
    lastSampleTime = now;

    int adcValue = analogRead(NTC_PIN);
    float voltage = adcValue * VREF / ADC_MAX;

    float safeVoltage = voltage;
    if (safeVoltage <= 0.001) {
      safeVoltage = 0.001;
    }
    if (safeVoltage >= VREF - 0.001) {
      safeVoltage = VREF - 0.001;
    }

    float resistanceOhms = FIXED_RESISTOR * safeVoltage / (VREF - safeVoltage);

    float temperatureC = 1.0 / (
      log(1.0 / (1023.0 / adcValue - 1.0)) / BETA + 1.0 / T0_K
    ) - 273.15;

    const char* status = getStatus(temperatureC);

    Serial.print(now);
    Serial.print(",");
    Serial.print(adcValue);
    Serial.print(",");
    Serial.print(voltage, 3);
    Serial.print(",");
    Serial.print(resistanceOhms, 1);
    Serial.print(",");
    Serial.print(temperatureC, 2);
    Serial.print(",");
    Serial.println(status);
  }
}