// CONSTANTS
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

// TITLE
#define TITLE "APS Slave Code"
#define VERSION "v0.0.8"
#define FEATURE "Check RFID on Firebase and Buzz if unverified"

#define DEV_ID "S000001"

// RGB
const int RGB_G_PIN = 5;  // D1
const int RGB_R_PIN = 4;  // D2

// Buzzer
const int BUZZER_PIN = 15;  // D8


String rfidDataContent = "";
unsigned long rfidAccessTime = 0;
bool rfidIsRemoved = false;
bool rfidIsVerified = false;
bool rfidIsDetectedOnce = false;

void setup() {
  rgbSetup();
  buzzerSetup();
  Serial.begin(115200);
  mcuShowVersion();
  pinMode(2, INPUT_PULLUP);
}

void loop() {
  detectRfidRemovalFromReader();
  lightGreenLED();
  sendUnoccupied();
  resetBuzzer();
  

  if (digitalRead(2))
    return;
  else 
    rfidAccessTime = millis();

  if (!rfidIsDetectedOnce) {
    rfidIsDetectedOnce = true;
    readRfidContent();
    showRfidTagToSerial();
    verifyRfid();
    lightRedLED();
    buzzBuzzer();
    sendOccupied();
  }
}

void detectRfidRemovalFromReader() {
  if (rfidDataContent != "" && (millis() - rfidAccessTime > 100)) {
    rfidIsRemoved = true;
    rfidDataContent = "";
    rfidIsDetectedOnce = false;
    Serial.println();
    Serial.println("RFID card removed!");
  } else {
    rfidIsRemoved = false;
  }
}

void lightGreenLED() {
  if (rfidIsRemoved) {
    Serial.println("Light Green LED!");
    rgbGreenOn();
  }
}

void sendUnoccupied() {
  if (rfidIsRemoved && rfidIsVerified) {
    Serial.println("Availability = 1");
  }
}

void resetBuzzer() {
  if (rfidIsRemoved && !rfidIsVerified) {
    Serial.println("Buzzer Off!");
    buzzerOff();
  }
}

void readRfidContent() {
  rfidDataContent = "";
  rfidDataContent = " 13 D0 A5 A1";
  rfidDataContent.toUpperCase();
}

void showRfidTagToSerial() {
  Serial.println();
  Serial.print(F("UID Tag:"));
  Serial.print(rfidDataContent);
  Serial.println();
}

void verifyRfid() {
  char rfidCharArray[16] = "";
  
  strcpy(rfidCharArray, " s13 D0 A5 A1");

  Serial.print("UID From Firebase:");
  Serial.println(rfidCharArray);

  if (strcmp(rfidCharArray, rfidDataContent.c_str()) == 0) {
    rfidIsVerified = true;
    Serial.println(rfidDataContent + " RFID found!");
  } else {
    rfidIsVerified = false;
    Serial.println(rfidDataContent + " RFID not found!");
  }
}

void lightRedLED() {
  Serial.println("Light Red LED!");
  rgbRedOn();
}

void buzzBuzzer() {
  if (!rfidIsVerified) {
    Serial.println("Buzzer On!");
    buzzerOn();
  }
}

void sendOccupied() {
  if (rfidIsVerified) {
    Serial.println("Availability = 0");
  }
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
void mcuShowVersion() {
  Serial.println();
  Serial.println(F(TITLE));
  Serial.println(F(VERSION));
  Serial.println(F(FEATURE));
  Serial.println();
}

// LED
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
void rgbSetup() {
  pinMode(RGB_G_PIN, OUTPUT);
  pinMode(RGB_R_PIN, OUTPUT);

  rgbGreenOn();
}

void rgbGreenOn() {
  digitalWrite(RGB_G_PIN, !HIGH);
  digitalWrite(RGB_R_PIN, !LOW);
}

void rgbRedOn() {
  digitalWrite(RGB_R_PIN, !HIGH);
  digitalWrite(RGB_G_PIN, !LOW);
}

// Buzzer
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
void buzzerSetup() {
  pinMode(BUZZER_PIN, OUTPUT);
}

void buzzerOn() {
  digitalWrite(BUZZER_PIN, HIGH);
}

void buzzerOff() {
  digitalWrite(BUZZER_PIN, LOW);
}