// Relay.ino
//
// 23.20.2022, Angelika Iskra
//
// Haier 8kW - płynne przejście z CWU na CO
//

const int relayPinCWU = 13;
const int relayPinCO = 12;
const int relayPin3D = 11;
const float BETA = 3950;

enum state {
  CO = 0, 
  CWU = 1, 
  CWUToCO = 2
};

enum state currentState = CO;
boolean cwuOn = true;
boolean coOn = true;

float heatingTemperature = 42;
float heatedTankTemperature = 46;

unsigned long timestamp;
const unsigned long interval = 18000;

const unsigned int MAX_MESSAGE_LENGTH = 12;

void setup() 
{
  Serial.begin(9600);

  pinMode(relayPinCWU, OUTPUT);
  pinMode(relayPinCO, OUTPUT);
  pinMode(relayPin3D, OUTPUT);

  changeToCO();
}

void loop() 
{
  int analogValue = analogRead(A0);
  float temperature = 1 / (log(1 / (1023. / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;

  Serial.print("Temperatura: ");
  Serial.print(temperature);
  Serial.print(" ℃. Tryb: ");
  switch (currentState) {
    case CO: Serial.println("centralne ogrzewanie budynku (CO)."); break;
    case CWU: Serial.println("grzanie wody użytkowej (CWU)."); break;
    case CWUToCO: Serial.println("przełączanie z CWU na CO."); break;
    default: Serial.println("nieznany.");
  }

  if (cwuOn && temperature < heatingTemperature && currentState == CO) {
    changeToCWU();

  } else if (temperature >= heatedTankTemperature && (currentState == CWU || currentState == CWUToCO)) {
    changeToCO();
  }
  
  readInput();

  delay(600);
}

void changeToCO() {
  unsigned long currentMillis = millis();

  if (currentState == CWU) {
    digitalWrite(relayPin3D, LOW);
    timestamp = currentMillis;
    currentState = CWUToCO;

  } else if (currentState == CWUToCO && currentMillis - timestamp >= interval) {
    digitalWrite(relayPinCO, HIGH);
    digitalWrite(relayPinCWU, LOW);

    currentState = CO;
  }
}

void changeToCWU() {
  if (!cwuOn) return;

  digitalWrite(relayPinCO, LOW);
  digitalWrite(relayPinCWU, HIGH);
  digitalWrite(relayPin3D, HIGH);

  currentState = CWU;
}

void readInput() {
   while (Serial.available() > 0)
    {
      static char message[MAX_MESSAGE_LENGTH];
      static unsigned int message_pos = 0;

      //Read the next available byte in the serial receive buffer
      char inByte = Serial.read();

      //Message coming in (check not terminating character) and guard for over message size
      if (inByte != '\n' && (message_pos < MAX_MESSAGE_LENGTH - 1)) {
        message[message_pos] = inByte;
        message_pos++;

      } else {
        message[message_pos] = '\0';
        handleInput(message);
        message_pos = 0;
      }
    }

}

void handleInput(String message) {
  Serial.println(message);

  if (message == "cwu on") {
    cwuOn = true;
  
  } else if (message == "cwu off") {
    cwuOn = false;
  
  } else if (message == "co on") {
    coOn = true;
  
  } else if (message == "co off") {
    coOn = false; 

  } else if (message.indexOf("heatingTemp") > 0) {
    message.remove(0, 12);
    int newTemp = (int)message;
    Serial.print("newTemp ");
    Serial.println(newTemp);
  }

}