using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System;

public class TurntableSensorCamera : MonoBehaviour
{
    public Transform target;
    public float distance;
    public float heightdistance;
    public bool useRelativeCameraRotation = true;
    // initial camera and sensor value
    private Quaternion initialCameraRotation = Quaternion.identity;
    List<Quaternion> quaternionList = new List<Quaternion>();
    private bool gotFirstValue = false;

    float timer = 0f;
    // Use this for initialization
    void Start()
    {
        Input.compass.enabled = true;
        // for distance calculation --> its much easier to make adjusments in the editor, just put
        // your camera where you want it to be
        if (target == null) { Debug.LogWarning("Warning! Target for TurntableSensorCamera is null."); return; }

        // if distance is set to zero, use current camera position --> easier setup
        if (distance == 0)
            distance = (transform.position - target.position).magnitude;
        heightdistance = -1;
        // if you start the app, you will be viewing in the same direction your unity camera looks right now
        if (useRelativeCameraRotation)
            initialCameraRotation = Quaternion.Euler(0, -transform.rotation.eulerAngles.y, 0);
        else
            initialCameraRotation = Quaternion.identity;
        print(-transform.rotation.eulerAngles.y);
        // direct call
        // Sensor.Activate(Sensor.Type.RotationVector);

        // SensorHelper call with fallback
        //		SensorHelper.ActivateRotation();
        SensorHelper.TryForceRotationFallback(RotationFallbackType.OrientationAndAcceleration);

        StartCoroutine(Calibration());
    }

    IEnumerator Calibration()
    {
        gotFirstValue = false;

        while (!SensorHelper.gotFirstValue)
        {
            SensorHelper.FetchValue();
            yield return null;
        }

        SensorHelper.FetchValue();

        // wait some frames
        yield return new WaitForSeconds(0.1f);

        // Initialize rotation values
        Quaternion initialSensorRotation = SensorHelper.rotation;
        initialCameraRotation *= Quaternion.Euler(0, Input.compass.trueHeading - initialSensorRotation.eulerAngles.y, 0);//真實方向

        // allow updates
        gotFirstValue = true;
    }
    AngleFilter magneticFilter = new AngleFilter(10);
    // Update is called once per frame
    void LateUpdate()
    {
        // first value gotten from sensor is the offset value for further processing
        if (useRelativeCameraRotation)
            if (!gotFirstValue) return;

        // do nothing if there is no target
        timer += Time.deltaTime;
        if (target == null) return;
        if (timer >= 1 && timer <= 1.5)
        {
            initialCameraRotation = Quaternion.identity;
            Quaternion initialSensorRotation = SensorHelper.rotation;
            switch (Input.deviceOrientation)
            {
                case DeviceOrientation.FaceDown://該裝置與地面平行，螢幕朝下。
                    initialCameraRotation *= Quaternion.Euler(0, initialSensorRotation.eulerAngles.y - Input.compass.trueHeading, 0);//真實方向
                    break;
                case DeviceOrientation.FaceUp://該裝置與地面平行，螢幕朝上。
                case DeviceOrientation.LandscapeLeft://裝置處於橫向模式，裝置保持直立狀態
                case DeviceOrientation.LandscapeRight://裝置處於橫向模式，裝置保持直立狀態
                case DeviceOrientation.Portrait://裝置處於豎屏模式，裝置保持直立狀態
                case DeviceOrientation.PortraitUpsideDown://該裝置處於豎屏模式，但上下顛倒，裝置直立。
                    initialCameraRotation *= Quaternion.Euler(0, Input.compass.trueHeading - initialSensorRotation.eulerAngles.y, 0);//真實方向
                    break;
            }
            Quaternion q = initialCameraRotation * SensorHelper.rotation;
            transform.rotation = Quaternion.Slerp(transform.rotation, q, 0.5f);
            if (timer > 1.5f)
                timer = 0;
        }
        else
        {
            quaternionList.Add(initialCameraRotation * SensorHelper.rotation);
            if (quaternionList.Count > 1)
            {
                Quaternion q = new Quaternion(Round(EndPosionManager.Average(quaternionList).x, 1), Round(EndPosionManager.Average(quaternionList).y, 1), Round(EndPosionManager.Average(quaternionList).z, 1), EndPosionManager.Average(quaternionList).w);

                transform.rotation = Quaternion.Slerp(transform.rotation, q, 0.2f);
                quaternionList.Clear();
            }
        }
        transform.position = target.position - transform.forward * distance - transform.up * heightdistance;
    }
    float Round(float x, int f)//四元數精度處理
    {
        float result = (float)Math.Round((double)x, f);
        return result;
    }