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

Adafruit_MPU6050 mpu;

#define BUZZER_PIN 25
#define SW420_PIN 35

float baseline = 0;
bool calibrated = false;

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

  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(SW420_PIN, INPUT_PULLUP);

  Wire.begin(21, 22);

  if (!mpu.begin()) {
    Serial.println("MPU6050 not found!");
    while (1);
  }

  Serial.println("Local Quake Alert started");
}

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

  float mag = sqrt(
    a.acceleration.x * a.acceleration.x +
    a.acceleration.y * a.acceleration.y +
    a.acceleration.z * a.acceleration.z
  );

  if (!calibrated) {
    baseline = mag;
    calibrated = true;
  }

  float vibration = abs(mag - baseline);
  bool sw420Triggered = digitalRead(SW420_PIN) == LOW;

  Serial.print("Vibration: ");
  Serial.print(vibration);
  Serial.print(" | SW420: ");
  Serial.println(sw420Triggered);

  if (sw420Triggered && vibration > 2.0) {
    digitalWrite(BUZZER_PIN, HIGH);
    Serial.println("!!! EARTHQUAKE ALERT !!!");
  } else {
    digitalWrite(BUZZER_PIN, LOW);
  }

  delay(50);
}