#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);

  const int ecgPin = 34;  // Potentiometer for ECG
  const int buttonPin = 25;  // Button for X-ray result
  #define MAX_SAMPLES 128
  int ecgBuffer[MAX_SAMPLES];
  int bufferIndex = 0;

  // ECG waveform parameters
  float heartRateBase = 60.0;
  const float pWave = 0.15, qrsWave = 0.7, tWave = 0.25;
  const float pTime = 0.08, qrsTime = 0.04, tTime = 0.15;

  void setup() {
    Serial.begin(115200);
    pinMode(buttonPin, INPUT_PULLUP);  // Button with internal pull-up

    Wire.begin(21, 22);
    if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
      Serial.println(F("SSD1306 failed"));
      for (;;);
    }
    display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(SSD1306_WHITE);
    display.setCursor(0, 0);
    display.println("ECG & X-Ray Kiosk");
    display.display();
    delay(2000);

    for (int i = 0; i < MAX_SAMPLES; i++) {
      ecgBuffer[i] = SCREEN_HEIGHT / 2;
    }
  }

  float generateECGWaveform(float t, float period) {
    float phase = fmod(t, period) / period;
    float ecg = 0.0;
    if (phase < 0.08) {
      ecg += pWave * sin(2 * PI * phase / pTime);
    }
    else if (phase < 0.12) {
      ecg += qrsWave * (sin(2 * PI * (phase - 0.08) / qrsTime) * 1.5 - 0.2);
    }
    else if (phase < 0.27) {
      ecg += tWave * sin(2 * PI * (phase - 0.12) / tTime);
    }
    return constrain(ecg * 25 + SCREEN_HEIGHT / 2, 10, 50);
  }

  void loop() {
    int potValue = analogRead(ecgPin);
    float heartRate = map(potValue, 0, 4095, 60, 120);
    float period = 1000.0 / (heartRate / 60.0);
    float t = millis() % (unsigned long)period;
    int ecgValue = (int)generateECGWaveform(t, period);
    ecgBuffer[bufferIndex] = ecgValue;

    static unsigned long lastPeak = 0;
    static int peakCount = 0;
    static unsigned long lastCheck = 0;
    int calculatedHeartRate = heartRate;
    if (ecgValue > SCREEN_HEIGHT / 2 + 15 && millis() - lastPeak > 150) {
      peakCount++;
      lastPeak = millis();
    }
    if (millis() - lastCheck > 60000) {
      calculatedHeartRate = peakCount;
      peakCount = 0;
      lastCheck = millis();
    }

    String ecgStatus = (calculatedHeartRate > 100) ? "Abnormal" : "Normal";
    static int xrayResult = 1;  // Default: Normal
    if (digitalRead(buttonPin) == LOW) {  // Button pressed
      xrayResult = !xrayResult;  // Toggle
      delay(200);  // Debounce
    }
    String xrayStatus = (xrayResult == 1) ? "Normal" : "Pneumonia Detected";

    display.clearDisplay();
    for (int x = 0; x < SCREEN_WIDTH; x += 25) {
      display.drawLine(x, 0, x, 48, SSD1306_WHITE);
    }
    for (int y = 0; y <= 48; y += 10) {
      display.drawLine(0, y, SCREEN_WIDTH, y, SSD1306_WHITE);
    }
    for (int i = 0; i < MAX_SAMPLES - 1; i++) {
      int x0 = i;
      int x1 = i + 1;
      int y0 = ecgBuffer[(bufferIndex + i) % MAX_SAMPLES];
      int y1 = ecgBuffer[(bufferIndex + i + 1) % MAX_SAMPLES];
      display.drawLine(x0, y0, x1, y1, SSD1306_WHITE);
    }

    display.setCursor(0, 50);
    display.print("HR:");
    display.print(calculatedHeartRate);
    display.print("bpm ");
    display.print(ecgStatus);
    display.setCursor(0, 58);
    display.print("X-Ray:");
    display.println(xrayStatus);
    display.display();

    Serial.print("ECG Value: ");
    Serial.print(potValue);
    Serial.print(", Voltage: ");
    Serial.print(potValue * (3.3 / 4095.0));
    Serial.print("V, Heart Rate: ");
    Serial.print(calculatedHeartRate);
    Serial.print(" bpm, ECG Status: ");
    Serial.print(ecgStatus);
    Serial.print(", X-Ray Status: ");
    Serial.println(xrayStatus);

    bufferIndex = (bufferIndex + 1) % MAX_SAMPLES;
    delay(20);
  }