#if UNITY_ANDROID && !UNITY_EDITOR
#define OVR_ANDROID_MRC
#endif

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

namespace MRCHelpers
{

    /// <summary>
    /// Triggers the Oculus MRC tracking engine if the scene uses the XR Interaction Toolkit. 
    /// The code is modified from the file OVRMixedRealityCaptureTest in Oculus plugin
    /// </summary>
    public class OVRMixedRealityCaptureTestMod : MonoBehaviour
    {

        bool inited = false;

        public Camera defaultExternalCamera;
        OVRPlugin.Fovf defaultFov;

        // Use this for initialization
        void Start()
        {
#if UNITY_EDITOR_WIN || UNITY_STANDALONE_WIN || OVR_ANDROID_MRC
            if (!defaultExternalCamera)
            {
                Debug.LogWarning("defaultExternalCamera undefined");
            }

#if !OVR_ANDROID_MRC
            // On Quest, we enable MRC automatically through the configuration
            if (!OVRManager.instance.enableMixedReality)
            {
                OVRManager.instance.enableMixedReality = true;
            }
#endif
#endif
        }

        void Initialize()
        {
#if UNITY_EDITOR_WIN || UNITY_STANDALONE_WIN || OVR_ANDROID_MRC
            if (inited)
                return;

#if OVR_ANDROID_MRC
		if (!OVRPlugin.Media.GetInitialized())
			return;
#else
            if (!OVRPlugin.IsMixedRealityInitialized())
                return;
#endif

            OVRPlugin.ResetDefaultExternalCamera();
            Debug.LogFormat("GetExternalCameraCount before adding manual external camera {0}", OVRPlugin.GetExternalCameraCount());
            UpdateDefaultExternalCamera();
            Debug.LogFormat("GetExternalCameraCount after adding manual external camera {0}", OVRPlugin.GetExternalCameraCount());

            // obtain default FOV
            {
                OVRPlugin.CameraIntrinsics cameraIntrinsics;
                OVRPlugin.CameraExtrinsics cameraExtrinsics;
                OVRPlugin.GetMixedRealityCameraInfo(0, out cameraExtrinsics, out cameraIntrinsics);
                defaultFov = cameraIntrinsics.FOVPort;
            }

            inited = true;
#endif
        }

        void UpdateDefaultExternalCamera()
        {
#if UNITY_EDITOR_WIN || UNITY_STANDALONE_WIN || OVR_ANDROID_MRC
            // always build a 1080p external camera
            const int cameraPixelWidth = 1920;
            const int cameraPixelHeight = 1080;
            const float cameraAspect = (float)cameraPixelWidth / cameraPixelHeight;


            string cameraName = "UnityExternalCamera";
            OVRPlugin.CameraIntrinsics cameraIntrinsics = new OVRPlugin.CameraIntrinsics();
            OVRPlugin.CameraExtrinsics cameraExtrinsics = new OVRPlugin.CameraExtrinsics();

            // intrinsics

            cameraIntrinsics.IsValid = OVRPlugin.Bool.True;
            cameraIntrinsics.LastChangedTimeSeconds = Time.time;

            float vFov = defaultExternalCamera.fieldOfView * Mathf.Deg2Rad;
            float hFov = Mathf.Atan(Mathf.Tan(vFov * 0.5f) * cameraAspect) * 2.0f;
            OVRPlugin.Fovf fov = new OVRPlugin.Fovf();
            fov.UpTan = fov.DownTan = Mathf.Tan(vFov * 0.5f);
            fov.LeftTan = fov.RightTan = Mathf.Tan(hFov * 0.5f);

            cameraIntrinsics.FOVPort = fov;
            cameraIntrinsics.VirtualNearPlaneDistanceMeters = defaultExternalCamera.nearClipPlane;
            cameraIntrinsics.VirtualFarPlaneDistanceMeters = defaultExternalCamera.farClipPlane;
            cameraIntrinsics.ImageSensorPixelResolution.w = cameraPixelWidth;
            cameraIntrinsics.ImageSensorPixelResolution.h = cameraPixelHeight;

            // extrinsics

            cameraExtrinsics.IsValid = OVRPlugin.Bool.True;
            cameraExtrinsics.LastChangedTimeSeconds = Time.time;
            cameraExtrinsics.CameraStatusData = OVRPlugin.CameraStatus.CameraStatus_Calibrated;
            cameraExtrinsics.AttachedToNode = OVRPlugin.Node.None;

            Camera mainCamera = Camera.main;

            Transform trackingSpace = Camera.main.transform.parent;
            OVRPose trackingSpacePose = trackingSpace.ToOVRPose(false);
            OVRPose cameraPose = defaultExternalCamera.transform.ToOVRPose(false);
            OVRPose relativePose = trackingSpacePose.Inverse() * cameraPose;
#if OVR_ANDROID_MRC
		OVRPose stageToLocalPose = OVRPlugin.GetTrackingTransformRelativePose(OVRPlugin.TrackingOrigin.Stage).ToOVRPose();
		OVRPose localToStagePose = stageToLocalPose.Inverse();
		relativePose = localToStagePose * relativePose;
#endif
            cameraExtrinsics.RelativePose = relativePose.ToPosef();

            if (!OVRPlugin.SetDefaultExternalCamera(cameraName, ref cameraIntrinsics, ref cameraExtrinsics))
            {
                Debug.LogError("SetDefaultExternalCamera() failed");
            }
#endif
        }

        // Update is called once per frame
        void Update()
        {
#if UNITY_EDITOR_WIN || UNITY_STANDALONE_WIN || OVR_ANDROID_MRC
            if (!inited)
            {
                Initialize();
                return;
            }

            if (!defaultExternalCamera)
            {
                return;
            }

#if OVR_ANDROID_MRC
		if (!OVRPlugin.Media.GetInitialized())
		{
			return;
		}
#else
            if (!OVRPlugin.IsMixedRealityInitialized())
            {
                return;
            }
#endif

            UpdateDefaultExternalCamera();
            OVRPlugin.OverrideExternalCameraFov(0, false, new OVRPlugin.Fovf());
            OVRPlugin.OverrideExternalCameraStaticPose(0, false, OVRPlugin.Posef.identity);
#endif
        }
    }

}