// ESP32 + HC-SR04 + 5 LED (yeşil/sarı/kırmızı) + Buzzer + OLED
// Park Sensörü — yaklaştıkça LED bar dolar, buzzer bip aralığı kısalır

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define TRIG_PIN   25
#define ECHO_PIN   26
#define BUZZER_PIN 5

// LED pinleri (uzaktan yakına)
const int LED_PINS[5] = { 2, 4, 15, 18, 19 };

#define SCREEN_W 128
#define SCREEN_H 64
#define OLED_ADDR 0x3C

Adafruit_SSD1306 oled(SCREEN_W, SCREEN_H, &Wire, -1);

long distanceCm = 999;
unsigned long lastBeepMs = 0;
bool beepState = false;

// ============ Helpers ============
void lcdAt(int x, int y, uint8_t size, const String &t) {
  oled.setTextSize(size);
  oled.setCursor(x, y);
  oled.print(t);
}

void centered(uint8_t y, uint8_t size, const String &t) {
  int w = t.length() * 6 * size;
  int x = (128 - w) / 2;
  if (x < 0) x = 0;
  lcdAt(x, y, size, t);
}

long readDistanceCm() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  long dur = pulseIn(ECHO_PIN, HIGH, 30000);
  if (dur == 0) return 999;
  return dur / 58;
}

// ============ Mesafe → LED sayısı, buzzer aralığı, durum ============
int ledsForDistance(long d) {
  if (d < 20)  return 5;
  if (d < 40)  return 4;
  if (d < 60)  return 3;
  if (d < 80)  return 2;
  if (d < 100) return 1;
  return 0;
}

int beepIntervalForDistance(long d) {
  if (d < 10)  return 0;      // Sürekli (alarm)
  if (d < 20)  return 100;    // Çok hızlı
  if (d < 40)  return 250;    // Hızlı
  if (d < 60)  return 500;    // Orta
  if (d < 80)  return 800;    // Yavaş
  if (d < 100) return 1200;   // Çok yavaş
  return -1;                  // Sessiz
}

String statusText(long d) {
  if (d < 10)  return "TEHLIKE!";
  if (d < 20)  return "DUR!";
  if (d < 40)  return "COK YAKIN";
  if (d < 60)  return "YAKIN";
  if (d < 80)  return "DIKKAT";
  if (d < 100) return "UZAK";
  return "SAKIN";
}

// ============ Ekranlar ============
void drawSplash() {
  oled.clearDisplay();
  oled.setTextColor(SSD1306_WHITE);
  centered(10, 2, "BlueGrays");
  centered(40, 1, "Park Sensoru v1");
  oled.drawRoundRect(2, 2, 124, 60, 6, SSD1306_WHITE);
  oled.display();
}

void drawStatus() {
  oled.clearDisplay();
  oled.setTextColor(SSD1306_WHITE);

  // Üst: başlık
  lcdAt(0, 0, 1, "> Park Sensoru");
  oled.drawLine(0, 10, 127, 10, SSD1306_WHITE);

  // Büyük mesafe cm
  String d = (distanceCm >= 999) ? "---" : String(distanceCm);
  centered(14, 3, d + " cm");

  // Durum metni
  centered(44, 1, statusText(distanceCm));

  oled.drawLine(0, 53, 127, 53, SSD1306_WHITE);

  // Alt: LED bar simülasyon (5 dörtgen)
  int leds = ledsForDistance(distanceCm);
  for (int i = 0; i < 5; i++) {
    int x = 10 + i * 22;
    if (i < leds) {
      oled.fillRect(x, 56, 18, 6, SSD1306_WHITE);
    } else {
      oled.drawRect(x, 56, 18, 6, SSD1306_WHITE);
    }
  }

  oled.display();
}

// ============ SETUP ============
void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  digitalWrite(BUZZER_PIN, LOW);

  for (int i = 0; i < 5; i++) {
    pinMode(LED_PINS[i], OUTPUT);
    digitalWrite(LED_PINS[i], LOW);
  }

  Wire.begin();
  if (!oled.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
    while (1);
  }

  drawSplash();
  delay(2500);
}

// ============ LOOP ============
void loop() {
  distanceCm = readDistanceCm();

  // LED bar güncelle
  int leds = ledsForDistance(distanceCm);
  for (int i = 0; i < 5; i++) {
    digitalWrite(LED_PINS[i], i < leds ? HIGH : LOW);
  }

  // Buzzer bip yönetimi
  int interval = beepIntervalForDistance(distanceCm);
  if (interval < 0) {
    digitalWrite(BUZZER_PIN, LOW);
    beepState = false;
  } else if (interval == 0) {
    digitalWrite(BUZZER_PIN, HIGH); // Sürekli alarm
  } else {
    if (millis() - lastBeepMs > interval) {
      lastBeepMs = millis();
      beepState = !beepState;
      digitalWrite(BUZZER_PIN, beepState ? HIGH : LOW);
    }
  }

  // Ekran güncelle (150ms)
  static unsigned long lastDraw = 0;
  if (millis() - lastDraw > 150) {
    lastDraw = millis();
    drawStatus();
  }

  delay(50);
}