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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1  // not used for I2C
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

Adafruit_MPU6050 mpu;

// Buzzer pin
#define BUZZER_PIN 19

// Fall detection thresholds
const float fallThreshold = 3.0; // Lower for testing in Wokwi

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

  pinMode(BUZZER_PIN, OUTPUT);
  digitalWrite(BUZZER_PIN, LOW);

  // Initialize OLED
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("SSD1306 failed");
    while (1);
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Initializing...");
  display.display();

  // Initialize MPU6050
  if (!mpu.begin()) {
    Serial.println("MPU6050 open failed");
    while (1);
  }
  mpu.setAccelerometerRange(MPU6050_RANGE_8_G);
  mpu.setFilterBandwidth(MPU6050_BAND_21_HZ);

  display.clearDisplay();
  display.setCursor(0, 0);
  display.println("Fall Detection Active");
  display.display();
  delay(1000);
}

void loop() {
  sensors_event_t a, g, temp;
  mpu.getEvent(&a, &g, &temp);

  float ax = a.acceleration.x;
  float ay = a.acceleration.y;
  float az = a.acceleration.z;
  float magnitude = sqrt(ax * ax + ay * ay + az * az);

  display.clearDisplay();
  display.setCursor(0, 0);
  display.setTextSize(1);
  display.print("Ax: "); display.println(ax, 2);
  display.print("Ay: "); display.println(ay, 2);
  display.print("Az: "); display.println(az, 2);
  display.print("Mag: "); display.println(magnitude, 2);

  if (magnitude > fallThreshold) {
    display.setTextSize(2);
    display.setCursor(0, 40);
    display.println("FALL!");
    display.display();

    // Buzz for 200ms
    digitalWrite(BUZZER_PIN, HIGH);
    delay(200);
    digitalWrite(BUZZER_PIN, LOW);
  } else {
    display.display();
  }

  delay(200);
}