package com.example.mycompass

import android.hardware.Sensor
import android.hardware.SensorEvent
import android.hardware.SensorEventListener
import android.hardware.SensorManager
import android.os.Bundle
import android.widget.ImageView
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity


class MainActivity : AppCompatActivity(){

    lateinit var imageView: ImageView
    lateinit var textView: TextView

    lateinit var sensorManager: SensorManager
    lateinit var sensorAccelerometer: Sensor
    lateinit var sensorMagneticField: Sensor

    private var floatGravity = FloatArray(3)
    private var floatGeoMagnetic = FloatArray(3)

    private val floatOrientation = FloatArray(3)
    private val floatRotationMatrix = FloatArray(9)

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        imageView = findViewById(R.id.imageView_compass)
        textView = findViewById(R.id.textView_under)

        sensorManager = getSystemService(SENSOR_SERVICE) as SensorManager
        sensorAccelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER)
        sensorMagneticField = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD)

        val sensorEventListenerAccelerometer: SensorEventListener = object : SensorEventListener {
            override fun onSensorChanged(event: SensorEvent) {
                floatGravity = event.values
                SensorManager.getRotationMatrix(
                    floatRotationMatrix,
                    null,
                    floatGravity,
                    floatGeoMagnetic
                )
                SensorManager.getOrientation(floatRotationMatrix, floatOrientation)
                val degree = (-floatOrientation[0] * 180 / 3.14159).toFloat()

                imageView.setRotation(degree)
                textView.setText(degree.toString())
            }

            override fun onAccuracyChanged(sensor: Sensor, accuracy: Int) {}
        }

        val sensorEventListenerMagneticField: SensorEventListener = object : SensorEventListener {
            override fun onSensorChanged(event: SensorEvent) {
                floatGeoMagnetic = event.values
                SensorManager.getRotationMatrix(
                    floatRotationMatrix,
                    null,
                    floatGravity,
                    floatGeoMagnetic
                )
                SensorManager.getOrientation(floatRotationMatrix, floatOrientation)
                val degree = (-floatOrientation[0] * 180 / 3.14159).toFloat()
                imageView.setRotation(degree)
                textView.setText(degree.toString())

            }
            override fun onAccuracyChanged(sensor: Sensor, accuracy: Int) {}
        }
        sensorManager.registerListener(
            sensorEventListenerAccelerometer,
            sensorAccelerometer,
            SensorManager.SENSOR_DELAY_NORMAL
        )
        sensorManager.registerListener(
            sensorEventListenerMagneticField,
            sensorMagneticField,
            SensorManager.SENSOR_DELAY_NORMAL
        )
    }

}