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

#define SCREEN_WIDTH 128  
#define SCREEN_HEIGHT 64  
#define OLED_RESET    -1  

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

// MQ Sensor Pins
#define MQ_BEFORE_PIN 12
#define MQ_AFTER_PIN 14

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

    if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
        Serial.println(F("SSD1306 allocation failed"));
        for (;;);
    }

    display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(WHITE);
    display.setCursor(0, 0);
    display.println("MQ Sensor Test");
    display.display();
    delay(2000);
}

void loop() {
    // Simulated readings (Replace with real MQ sensor values)
    float mq_before = analogRead(MQ_BEFORE_PIN) * 0.1;  // Convert to PPM (example)
    float mq_after = analogRead(MQ_AFTER_PIN) * 0.1;    

    // Calculate Efficiency
    float efficiency = 0;
    if (mq_before > 0) {
        efficiency = ((mq_before - mq_after) / mq_before) * 100;
    }

    // Print values to Serial Monitor with labels & units
    Serial.print("MQ Before: ");
    Serial.print(mq_before);
    Serial.println(" PPM");

    Serial.print("MQ After: ");
    Serial.print(mq_after);
    Serial.println(" PPM");

    Serial.print("Efficiency: ");
    Serial.print(efficiency);
    Serial.println(" %");

    Serial.println("---------------------");  // Separator

    // Display on OLED
    display.clearDisplay();
    display.setCursor(0, 0);
    display.println("MQ Sensor Readings:");
    display.setCursor(0, 15);
    display.print("Before: ");
    display.print(mq_before);
    display.println(" PPM");
    display.setCursor(0, 30);
    display.print("After: ");
    display.print(mq_after);
    display.println(" PPM");
    display.setCursor(0, 45);
    display.print("Eff: ");
    display.print(efficiency);
    display.println(" %");
    display.display();

    delay(2000); 
}