using System.Linq;
using System.Collections;
using System.Collections.Generic;

using UnityEngine;

public class InputHandler : MonoBehaviour, IGameComponent
{
    enum Axis
    {
        x,
        y,
        z,
        w
    }

    private Transform cameraTransform;

    private float X0;
    private float P0;
    private readonly float F = 1;
    private readonly float Q = 6;
    private readonly float H = 1;
    private readonly float R = 15;

    private float Covariance = .1f;
    private float[] state = new float[4];

    float GetValueAfterFilter(float value, Axis axis)
    {
        X0 = F * state[(int)axis];
        P0 = F * Covariance * F + Q;

        var K = H *P0 / (H * P0 * H + R);
        state[(int)axis] = X0 + K * (value - H * X0);
        Covariance = (1 - K * H) * P0;

        return state[(int)axis];
    }

    void Awake()
    {
        cameraTransform = transform;
    }

    void Start()
    {
        GameSystem.Instance.AddGameComponent(this);
        Input.gyro.enabled = true;
    }

    public void OnUpdate()
    {
        var phoneRotation = Input.gyro.attitude;
        cameraTransform.rotation = phoneRotation;

        cameraTransform.Rotate(0, 0, 180, Space.Self);
        cameraTransform.Rotate(90, 180, 0, Space.World);
    }

    public void OnFixedUpdate() { }
    public void OnLateUpdate() { }

    public void OnDestroy()
    {
        GameSystem.Instance.RemoveGameComponent(this);
    }
}