#include <DHT.h>

/*
  DHT22 Sensor with RGB LED, Buzzer, and Switch Control
  This program reads temperature and humidity, controls an RGB LED based on humidity,
  triggers a buzzer for high humidity, and allows switch override for LED color.
*/

// Pin Definitions
#define DHT_PIN 4         // Data pin for DHT22 sensor
#define DHT_TYPE DHT22    // Sensor type
#define RGB_RED 16        // Red LED pin (PWM capable)
#define RGB_GREEN 17      // Green LED pin (PWM capable)
#define RGB_BLUE 18       // Blue LED pin (PWM capable)
#define BUZZER 19         // Buzzer control pin
#define SWITCH 26         // Toggle switch pin

// Initialize DHT sensor
DHT dht(DHT_PIN, DHT_TYPE);

// Interrupt Variables (volatile because used in interrupt)
volatile bool switchState = false;    // Stores current switch position
volatile bool overrideLED = false;    // Flag for LED override mode
volatile unsigned long lastSwitchTime = 0; // Tracks last switch activation time

// INTERRUPT SERVICE ROUTINE (Triggered on switch change)
void IRAM_ATTR handleSwitch() {
  switchState = digitalRead(SWITCH);  // Read current switch state
  overrideLED = true;                // Activate LED override
  lastSwitchTime = millis();          // Record activation time
}

void setup() {
  Serial.begin(115200);
  Serial.println("Initializing system...");

  // Sensor and Device Setup
  dht.begin();
  pinMode(RGB_RED, OUTPUT);
  pinMode(RGB_GREEN, OUTPUT);
  pinMode(RGB_BLUE, OUTPUT);
  
  // Buzzer Setup (start turned off)
  pinMode(BUZZER, OUTPUT);
  digitalWrite(BUZZER, LOW);
  
  // Switch Setup with Interrupt
  pinMode(SWITCH, INPUT);
  attachInterrupt(digitalPinToInterrupt(SWITCH), handleSwitch, CHANGE);

  // Initialize LED to off
  analogWrite(RGB_RED, 0);
  analogWrite(RGB_GREEN, 0);
  analogWrite(RGB_BLUE, 0);

  Serial.println("System Ready!");
  Serial.println("DHT22 Sensor Test with RGB LED, Buzzer, and Switch");
  Serial.println("Humidity (%)\tTemperature (C)");
  delay(2000);  // Initial stabilization delay
}

void loop() {
  static bool prevOverride = false;  // Track previous override state

  // Check if override should expire after 2 seconds
  if (overrideLED && (millis() - lastSwitchTime >= 2000)) {
    overrideLED = false;
    Serial.println("LED override timed out. Returning to humidity mode.");
  }

  // Detect override state changes
  if (overrideLED != prevOverride) {
    if (overrideLED) {
      Serial.print("Switch override activated. Position: ");
      Serial.println(switchState ? "LEFT (Pink)" : "RIGHT (Cyan)");
    }
    prevOverride = overrideLED;
  }

  // Read sensor data
  float humidity = 85;// dht.readHumidity();
  float temperature = dht.readTemperature();

  // Check if readings failed
  if (isnan(humidity) || isnan(temperature)) {
    Serial.println("Error: Failed to read from DHT sensor!");
  } else {
    // Print sensor values
    Serial.print("Humidity: ");
    Serial.print(humidity);
    Serial.print("%\tTemperature: ");
    Serial.print(temperature);
    Serial.println("°C");

    // LED Control Logic
    if (overrideLED) {
      // Switch override colors
      if (switchState) {  // LEFT position
        analogWrite(RGB_RED, 255);   // Pink
        analogWrite(RGB_GREEN, 192);
        analogWrite(RGB_BLUE, 203);
        Serial.println("LED override: Pink (LEFT position)");
      } else {            // RIGHT position
        analogWrite(RGB_RED, 0);     // Cyan
        analogWrite(RGB_GREEN, 255);
        analogWrite(RGB_BLUE, 255);
        Serial.println("LED override: Cyan (RIGHT position)");
      }
    } else {
      // Normal humidity-based colors
      setRGBColor(humidity);
    }

    // Buzzer activation for high humidity
    if (humidity > 80) {
      tone(BUZZER, 1000, 500);
      Serial.println("Warning! High humidity detected - Buzzer activated");
    }
  }

  delay(2000);  // Wait 2 seconds between readings
}

void setRGBColor(float humidity) {
  int red = 0, green = 0, blue = 0;
  String colorName = "Off";  // Default color name

  // Determine color based on humidity ranges
  if (humidity >= 30 && humidity < 40) {
    red = 255; green = 255; blue = 255;  // White
    colorName = "White";
  } else if (humidity >= 40 && humidity < 50) {
    red = 0; green = 0; blue = 255;      // Blue
    colorName = "Blue";
  } else if (humidity >= 50 && humidity < 60) {
    red = 0; green = 255; blue = 0;      // Green
    colorName = "Green";
  } else if (humidity >= 60 && humidity < 70) {
    red = 255; green = 255; blue = 0;    // Yellow
    colorName = "Yellow";
  } else if (humidity >= 70 && humidity < 80) {
    red = 255; green = 165; blue = 0;    // Orange
    colorName = "Orange";
  } else if (humidity >= 80 && humidity < 90) {
    red = 255; green = 0; blue = 0;      // Red
    colorName = "Red";
  } else if (humidity >= 90 && humidity <= 100) {
    red = 128; green = 0; blue = 128;    // Purple
    colorName = "Purple";
  }

  // Apply colors and send debug info
  analogWrite(RGB_RED, red);
  analogWrite(RGB_GREEN, green);
  analogWrite(RGB_BLUE, blue);
  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.print("% - Setting LED to: ");
  Serial.println(colorName);
}