#define BLYNK_TEMPLATE_ID "TMPL6PfOvZcTL"
#define BLYNK_TEMPLATE_NAME "Smart Parking Assistant"
#define BLYNK_AUTH_TOKEN "VqBmfEj_RKQwM_95ttADl0mRYGtBO6UU"

#include <WiFi.h>
#include <BlynkSimpleEsp32.h>

char ssid[] = "Wokwi-GUEST";
char pass[] = "";

#define TRIG_PIN   5
#define ECHO_PIN   18
#define BUZZER_PIN 19
#define LED_RED    25
#define LED_GREEN  26
#define LED_BLUE   27

#define DANGER_THRESHOLD  10
#define CAUTION_THRESHOLD 30

#define SERIAL_INTERVAL   500
#define BUZZ_FAST_ON      100
#define BUZZ_FAST_OFF     100
#define BUZZ_SLOW_ON      300
#define BUZZ_SLOW_OFF     600

BlynkTimer timer;

unsigned long lastSerialTime  = 0;
unsigned long lastBuzzToggle  = 0;
bool          buzzState       = false;
float         currentDistance = 0.0;

enum ParkingState { SAFE, CAUTION_STATE, DANGER_STATE };
ParkingState  parkingState    = SAFE;


void setup() {
  Serial.begin(115200);

  pinMode(TRIG_PIN,   OUTPUT);
  pinMode(ECHO_PIN,   INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_RED,    OUTPUT);
  pinMode(LED_GREEN,  OUTPUT);
  pinMode(LED_BLUE,   OUTPUT);

  digitalWrite(BUZZER_PIN, LOW);
  setLED(0, 255, 0);

  Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);

  timer.setInterval(SERIAL_INTERVAL, updateBlynk);

  Serial.println("=== Smart Parking Assistant Ready ===");
}


void loop() {
  Blynk.run();
  timer.run();

  currentDistance = measureDistance();

  if (currentDistance < DANGER_THRESHOLD) {
    parkingState = DANGER_STATE;
  } else if (currentDistance < CAUTION_THRESHOLD) {
    parkingState = CAUTION_STATE;
  } else {
    parkingState = SAFE;
  }

  applyLocalResponse();

  if (millis() - lastSerialTime >= SERIAL_INTERVAL) {
    lastSerialTime = millis();
    Serial.printf("[Parking] Distance: %.1f cm  |  Status: %s\n",
                  currentDistance, statusLabel());
  }
}


float measureDistance() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  long duration = pulseIn(ECHO_PIN, HIGH, 30000UL); 
  if (duration == 0) return 400.0;                 

  return (duration * 0.0343f) / 2.0f;
}


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

  switch (parkingState) {

    case DANGER_STATE:
      setLED(255, 0, 0);  
      if (now - lastBuzzToggle >= (buzzState ? BUZZ_FAST_ON : BUZZ_FAST_OFF)) {
        buzzState = !buzzState;
        digitalWrite(BUZZER_PIN, buzzState ? HIGH : LOW);
        lastBuzzToggle = now;
      }
      break;

    case CAUTION_STATE:
      setLED(255, 150, 0);
      if (now - lastBuzzToggle >= (buzzState ? BUZZ_SLOW_ON : BUZZ_SLOW_OFF)) {
        buzzState = !buzzState;
        digitalWrite(BUZZER_PIN, buzzState ? HIGH : LOW);
        lastBuzzToggle = now;
      }
      break;

    case SAFE:
    default:
      setLED(0, 255, 0);
      digitalWrite(BUZZER_PIN, LOW);
      buzzState = false;
      break;
  }
}


void setLED(uint8_t r, uint8_t g, uint8_t b) {
  analogWrite(LED_RED,   r);
  analogWrite(LED_GREEN, g);
  analogWrite(LED_BLUE,  b);
}


void updateBlynk() {
  Blynk.virtualWrite(V0, currentDistance);

  Blynk.virtualWrite(V1, currentDistance);

  Blynk.virtualWrite(V2, parkingState == DANGER_STATE  ? 255 : 0);
  Blynk.virtualWrite(V3, parkingState == CAUTION_STATE ? 255 : 0);
  Blynk.virtualWrite(V4, parkingState == SAFE          ? 255 : 0);

  Blynk.virtualWrite(V5, statusLabel());
}


const char* statusLabel() {
  switch (parkingState) {
    case DANGER_STATE:  return "DANGER";
    case CAUTION_STATE: return "CAUTION";
    default:            return "SAFE";
  }
}