/************************************************************************************
Copyright : Copyright (c) Facebook Technologies, LLC and its affiliates. All rights reserved.

Your use of this SDK or tool is subject to the Oculus SDK License Agreement, available at
https://developer.oculus.com/licenses/oculussdk/

Unless required by applicable law or agreed to in writing, the Utilities SDK distributed
under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
ANY KIND, either express or implied. See the License for the specific language governing
permissions and limitations under the License.
************************************************************************************/

#if USING_XR_MANAGEMENT && USING_XR_SDK_OCULUS
#define USING_XR_SDK
#endif

#if UNITY_2020_1_OR_NEWER
#define REQUIRES_XR_SDK
#endif

using UnityEngine;
using System.Collections;

#if USING_XR_SDK
using UnityEngine.XR;
using UnityEngine.Experimental.XR;
#endif

/// <summary>
/// This is a simple behavior that can be attached to a parent of the CameraRig in order
/// to provide movement via the gamepad. This is useful when testing an application in
/// the Unity editor without the HMD.
/// To use it, create a game object in your scene and drag your CameraRig to be a child
/// of the game object. Then, add the OVRDebugHeadController behavior to the game object.
/// Alternatively, this behavior can be placed directly on the OVRCameraRig object, but
/// that is not guaranteed to work if OVRCameraRig functionality changes in the future.
/// In the parent case, the object with OVRDebugHeadController can be thougt of as a
/// platform that your camera is attached to. When the platform moves or rotates, the
/// camera moves or rotates, but the camera can still move independently while "on" the
/// platform.
/// In general, this behavior should be disabled when not debugging.
/// </summary>
public class OVRDebugHeadController : MonoBehaviour
{
	[SerializeField]
	public bool AllowPitchLook = false;
	[SerializeField]
	public bool AllowYawLook = true;
	[SerializeField]
	public bool InvertPitch = false;
	[SerializeField]
	public float GamePad_PitchDegreesPerSec = 90.0f;
	[SerializeField]
	public float GamePad_YawDegreesPerSec = 90.0f;
	[SerializeField]
	public bool AllowMovement = false;
	[SerializeField]
	public float ForwardSpeed = 2.0f;
	[SerializeField]
	public float StrafeSpeed = 2.0f;

	protected OVRCameraRig CameraRig = null;

	void Awake()
	{
		// locate the camera rig so we can use it to get the current camera transform each frame
		OVRCameraRig[] CameraRigs = gameObject.GetComponentsInChildren<OVRCameraRig>();

		if( CameraRigs.Length == 0 )
			Debug.LogWarning("OVRCamParent: No OVRCameraRig attached.");
		else if (CameraRigs.Length > 1)
			Debug.LogWarning("OVRCamParent: More then 1 OVRCameraRig attached.");
		else
			CameraRig = CameraRigs[0];
	}

	// Use this for initialization
	void Start ()
	{

	}

	// Update is called once per frame
	void Update ()
	{
		if ( AllowMovement )
		{
			float gamePad_FwdAxis = OVRInput.Get(OVRInput.RawAxis2D.LThumbstick).y;
			float gamePad_StrafeAxis = OVRInput.Get(OVRInput.RawAxis2D.LThumbstick).x;

			Vector3 fwdMove = ( CameraRig.centerEyeAnchor.rotation * Vector3.forward ) * gamePad_FwdAxis * Time.deltaTime * ForwardSpeed;
			Vector3 strafeMove = ( CameraRig.centerEyeAnchor.rotation * Vector3.right ) * gamePad_StrafeAxis * Time.deltaTime * StrafeSpeed;
			transform.position += fwdMove + strafeMove;
		}

		bool hasDevice = false;
#if USING_XR_SDK
		XRDisplaySubsystem currentDisplaySubsystem = OVRManager.GetCurrentDisplaySubsystem();
		if (currentDisplaySubsystem != null)
			hasDevice = currentDisplaySubsystem.running;
#elif REQUIRES_XR_SDK
		hasDevice = false;
#else
		hasDevice = UnityEngine.XR.XRDevice.isPresent;
#endif

		if ( !hasDevice && ( AllowYawLook || AllowPitchLook ) )
		{
			Quaternion r = transform.rotation;
			if ( AllowYawLook )
			{
				float gamePadYaw = OVRInput.Get(OVRInput.RawAxis2D.RThumbstick).x;
				float yawAmount = gamePadYaw * Time.deltaTime * GamePad_YawDegreesPerSec;
				Quaternion yawRot = Quaternion.AngleAxis( yawAmount, Vector3.up );
				r = yawRot * r;
			}
			if ( AllowPitchLook )
			{
				float gamePadPitch = OVRInput.Get(OVRInput.RawAxis2D.RThumbstick).y;
				if ( Mathf.Abs( gamePadPitch ) > 0.0001f )
				{
					if ( InvertPitch )
					{
						gamePadPitch *= -1.0f;
					}
					float pitchAmount = gamePadPitch * Time.deltaTime * GamePad_PitchDegreesPerSec;
					Quaternion pitchRot = Quaternion.AngleAxis( pitchAmount, Vector3.left );
					r = r * pitchRot;
				}
			}

			transform.rotation = r;
		}
	}
}