#include <DHT.h>
#include <Wire.h>              // 🆕 I2C protocol
#include <Adafruit_GFX.h>      // 🆕 Graphics library
#include <Adafruit_SSD1306.h>  // 🆕 OLED library

// ========== PIN DEFINITIONS ==========
#define LED_PIN    2   // Red LED
#define PIR_PIN    13  // Motion Sensor
#define DHT_PIN    15  // DHT22 Data
#define LDR_PIN    4   // Light Sensor
#define MQ2_PIN    5   // 🆕 MQ-2 Gas/Smoke Sensor
#define DHTTYPE DHT22


// 🆕 RGB LED Pins
#define RGB_RED    8   // Red channel
#define RGB_GREEN  9   // Green channel
#define RGB_BLUE   10  // Blue channel

// ========== OLED DISPLAY SETUP ==========
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1  // Reset pin (nuk përdoret në I2C)
#define OLED_ADDRESS 0x3C  // I2C address

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// 🆕 Buzzer
#define BUZZER_PIN 11  // Buzzer
#define BUTTON_PIN 12  // Push button


// ========== RGB LED CONTROL FUNCTION ==========
void setRGBColor(int red, int green, int blue) {
  analogWrite(RGB_RED, red);     // 0-255
  analogWrite(RGB_GREEN, green); // 0-255
  analogWrite(RGB_BLUE, blue);   // 0-255
}

// Quick color helpers
void rgbRed() { setRGBColor(255, 0, 0); }      // DANGER
void rgbYellow() { setRGBColor(255, 255, 0); } // WARNING
void rgbGreen() { setRGBColor(0, 255, 0); }    // OCCUPIED
void rgbBlue() { setRGBColor(0, 0, 255); }     // EMPTY
void rgbOff() { setRGBColor(0, 0, 0); }        // OFF

// ========== INITIALIZE SENSORS ==========
DHT dht(DHT_PIN, DHTTYPE);

void setup() {
  // Start Serial Monitor
  Serial.begin(115200);
  
  // Configure pins
  pinMode(LED_PIN, OUTPUT);
  pinMode(PIR_PIN, INPUT);
  pinMode(LDR_PIN, INPUT);
  pinMode(MQ2_PIN, INPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  
    // 🆕 RGB LED pins
  pinMode(RGB_RED, OUTPUT);
  pinMode(RGB_GREEN, OUTPUT);
  pinMode(RGB_BLUE, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  // Start DHT22
  dht.begin();
  
    // Test RGB on startup (optional)
  rgbRed(); delay(500);
  rgbGreen(); delay(500);
  rgbBlue(); delay(500);
  rgbOff();
  
  // Welcome message
  Serial.println("\n╔════════════════════════════════════╗");
  Serial.println("║  SMART ROOM OCCUPANCY SYSTEM      ║");
  Serial.println("║  ESP32-S3 IoT Project             ║");
  Serial.println("╚════════════════════════════════════╝\n");
  
  delay(2000);  // DHT22 needs 2 sec to stabilize
}

void loop() {
  Serial.println("━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━");
  Serial.println("📊 SENSOR READINGS");
  Serial.println("━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━\n");
  
  // ========== READ DHT22 ==========
  Serial.println("🌡️  [DHT22 - Temperature & Humidity]");
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();
  
  if (isnan(temperature) || isnan(humidity)) {
    Serial.println("   ❌ ERROR: Cannot read DHT22!");
    Serial.println("   → Check GPIO 15, VCC, GND\n");
  } else {
    Serial.print("   Temperature: ");
    Serial.print(temperature);
    Serial.println("°C ✅");
    
    Serial.print("   Humidity: ");
    Serial.print(humidity);
    Serial.println("% ✅\n");
  }
  
  // ========== READ PIR ==========
  Serial.println("👤 [PIR - Motion Detection]");
  int motion = digitalRead(PIR_PIN);
  
  if (motion == HIGH) {
    Serial.println("   🚶 MOTION DETECTED! ✅");
    digitalWrite(LED_PIN, HIGH);  // Turn LED ON
    Serial.println("   💡 LED Status: ON\n");
  } else {
    Serial.println("   ⚪ No motion detected");
    digitalWrite(LED_PIN, LOW);   // Turn LED OFF
    Serial.println("   💡 LED Status: OFF\n");
  }
  
  // ========== READ LDR ==========
  Serial.println("💡 [LDR - Light Sensor]");
  int lightRaw = analogRead(LDR_PIN);
  float lightPercent = (lightRaw / 4095.0) * 100;
  
  Serial.print("   Raw Value: ");
  Serial.print(lightRaw);
  Serial.println(" (0-4095) ✅");
  
  Serial.print("   Light Level: ");
  Serial.print(lightPercent, 1);
  Serial.println("%");
  
  // Light interpretation
  if (lightPercent < 20) {
    Serial.println("   → 🌙 Dark room\n");
  } else if (lightPercent < 60) {
    Serial.println("   → 🏠 Normal lighting\n");
  } else {
    Serial.println("   → ☀️  Bright room\n");
  }

  // ========== READ MQ-2 (Gas/Smoke Sensor) ==========
  Serial.println("🔥 [MQ-2 - Gas/Smoke Detection]");
  int gasValue = analogRead(MQ2_PIN);  // 0-4095
  float gasPercent = (gasValue / 4095.0) * 100;
  
  Serial.print("   Raw Value: ");
  Serial.print(gasValue);
  Serial.println(" (0-4095) ✅");
  
  Serial.print("   Gas Level: ");
  Serial.print(gasPercent, 1);
  Serial.println("%");
  
  // Gas interpretation
  if (gasValue < 500) {
    Serial.println("   → ✅ Air Quality: GOOD\n");
  } else if (gasValue < 1500) {
    Serial.println("   → ⚠️  Air Quality: MODERATE (Ventilation needed)\n");
  } else if (gasValue < 2500) {
    Serial.println("   → ❌ Air Quality: POOR (High gas detected!)\n");
  } else {
    Serial.println("   → 🚨 DANGER: Smoke/Gas leak detected!\n");
  }
  
  // ========== SYSTEM STATUS ==========
  Serial.println("🔧 [SYSTEM INFO]");
  Serial.print("   Uptime: ");
  Serial.print(millis() / 1000);
  Serial.println(" seconds");
  
  Serial.print("   Free Memory: ");
  Serial.print(ESP.getFreeHeap());
  Serial.println(" bytes\n");
  
  Serial.println("━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━");
  Serial.println("⏳ Next reading in 3 seconds...\n\n");
  
  delay(3000);  // Wait 3 seconds

    // ========== RGB LED STATUS ==========
  Serial.println("🎨 [RGB LED - System Status]");
  
  // Priority 1: DANGER (High gas)
  if (gasValue > 2500) {
    rgbRed();
    Serial.println("   🔴 RED - DANGER! Gas leak!\n");
  }
  // Priority 2: WARNING (Moderate gas)
  else if (gasValue > 1500) {
    rgbYellow();
    Serial.println("   🟡 YELLOW - Warning, ventilate!\n");
  }
  // Priority 3: OCCUPIED (Motion + Safe)
  else if (motion == HIGH) {
    rgbGreen();
    Serial.println("   🟢 GREEN - Room occupied\n");
  }
  // Priority 4: EMPTY (No motion)
  else {
    rgbBlue();
    Serial.println("   🔵 BLUE - Room empty\n");
  }

    // ========== BUZZER ALERT ==========
  if (gasValue > 2500) {
    // DANGER level - sound alarm!
    tone(BUZZER_PIN, 2000, 500);  // 2kHz beep for 500ms
    Serial.println("🔔 BUZZER: ALARM ACTIVE!\n");
  }
  else if (gasValue > 1500) {
    // WARNING level - short beep
    tone(BUZZER_PIN, 1000, 200);  // 1kHz beep for 200ms
  }

    // 🆕 Initialize OLED
  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDRESS)) {
    Serial.println(F("❌ OLED allocation failed!"));
    for (;;);  // Loop forever
  }
  
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("SMART ROOM");
  display.println("Initializing...");
  display.display();
  delay(2000);

  // ========== UPDATE OLED DISPLAY ==========
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  
  // Header
  display.println("SMART ROOM v1.0");
  display.println("---------------");
  
  // Temperature
  display.print("Temp: ");
  display.print(temperature, 1);
  display.println("C");
  
  // Humidity
  display.print("Hum:  ");
  display.print(humidity, 1);
  display.println("%");
  
  // Motion
  display.print("Motion: ");
  display.println(motion ? "YES" : "NO ");
  
  // Light
  display.print("Light:  ");
  display.print((lightRaw / 4095.0) * 100, 0);
  display.println("%");
  
  // Gas
  display.print("Gas:  ");
  if (gasValue > 2500) {
    display.println("DANGER!");
  } else if (gasValue > 1500) {
    display.println("WARNING");
  } else {
    display.println("GOOD   ");
  }
  
  display.display();  // Push to screen

  // ========== BUTTON CHECK ==========
  int buttonState = digitalRead(BUTTON_PIN);
  
  if (buttonState == LOW) {  // Button pressed (pull-up inverts)
    Serial.println("🔘 BUTTON PRESSED - Manual override!");
    digitalWrite(LED_PIN, HIGH);  // Force LED ON
    rgbWhite();  // RGB white = manual mode
  }
}