#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_MPU6050.h>

// Standard I2C Pins for ESP32
#define SDA_PIN 21
#define SCL_PIN 22

// Analog Pin Definitions
const int HB100_PIN = 34;      // Radar (Chest Motion)
const int THERM_PIN = 32;      // Thermistor (Nasal Airflow)
const int ECG_PIN = 35;        // AD8232 (Heart Activity)
const int BUZZER_PIN = 13;     // Alarm

Adafruit_SSD1306 display(128, 64, &Wire, -1);
Adafruit_MPU6050 mpu;

void setup() {
  Serial.begin(115200);
  Wire.begin(SDA_PIN, SCL_PIN);
  
  pinMode(BUZZER_PIN, OUTPUT);

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
    Serial.println("OLED missing"); 
  }
  
  if (!mpu.begin()) { 
    Serial.println("MPU6050 missing"); 
  }

  display.clearDisplay();
  display.setTextColor(WHITE);
}

void loop() {
  // 1. Read SpO2 (I2C Custom Chip)
  Wire.requestFrom(0x57, 1);
  int spo2 = Wire.available() ? Wire.read() : 98;

  // 2. Read Analog Inputs (Custom Chips)
  int hb100 = analogRead(HB100_PIN);
  int therm = analogRead(THERM_PIN);
  int ecg = analogRead(ECG_PIN);

  // 3. Read Motion (MPU6050)
  sensors_event_t a, g, temp;
  mpu.getEvent(&a, &g, &temp);
  float motion = abs(a.acceleration.x) + abs(a.acceleration.y);

  // --- 4/5 APNEA LOGIC ---
  int alerts = 0;
  if (spo2 < 92) alerts++;          // Param 1: Low Oxygen
  if (hb100 < 500) alerts++;        // Param 2: No Chest Motion (Radar)
  if (therm < 500) alerts++;        // Param 3: No Nasal Airflow (Thermistor)
  if (ecg > 3000) alerts++;         // Param 4: Cardiac Stress (ECG)
  if (motion > 15.0) alerts++;      // Param 5: Sleep Fragmentation (Motion)

  display.clearDisplay();
  display.setCursor(0,0);

  if (alerts >= 4) {
    // APNEA DETECTED
    display.invertDisplay(true);
    display.setTextSize(2);
    display.println("!! APNEA !!");
    display.setTextSize(1);
    display.println("\n4/5 Params Abnormal");
    display.println("CHECK PATIENT!");
    digitalWrite(BUZZER_PIN, HIGH); // Alarm ON
  } else {
    // NORMAL MONITORING
    display.invertDisplay(false);
    display.setTextSize(1);
    display.println("MONITORING SYSTEM");
    display.drawFastHLine(0, 10, 128, WHITE);
    display.setCursor(0, 15);
    display.print("SpO2: "); display.print(spo2); display.println("%");
    display.print("Flow: "); display.println(therm < 500 ? "BLOCK" : "OK");
    display.print("Chest:"); display.println(hb100 < 500 ? "STOP" : "OK");
    display.print("Heart:"); display.println(ecg > 3000 ? "STRESS" : "Normal");
    display.print("Move: "); display.println(motion > 10 ? "HIGH" : "Steady");
    digitalWrite(BUZZER_PIN, LOW); // Alarm OFF
  }
  
  display.display();
  delay(300);
}