/************************************************************************************
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.
************************************************************************************/

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

[DefaultExecutionOrder(-80)]
public class OVRMesh : MonoBehaviour
{
	public interface IOVRMeshDataProvider
	{
		MeshType GetMeshType();
	}

	public enum MeshType
	{
		None = OVRPlugin.MeshType.None,
		HandLeft = OVRPlugin.MeshType.HandLeft,
		HandRight = OVRPlugin.MeshType.HandRight,
	}

	[SerializeField]
	private IOVRMeshDataProvider _dataProvider;
	[SerializeField]
	private MeshType _meshType = MeshType.None;
	private Mesh _mesh;

	public bool IsInitialized { get; private set; }

	public Mesh Mesh
	{
		get { return _mesh; }
	}

	private void Awake()
	{
		if (_dataProvider == null)
		{
			_dataProvider = GetComponent<IOVRMeshDataProvider>();
		}

		if (_dataProvider != null)
		{
			_meshType = _dataProvider.GetMeshType();
		}

		if (ShouldInitialize())
		{
			Initialize(_meshType);
		}
	}

	private bool ShouldInitialize()
	{
		if (IsInitialized)
		{
			return false;
		}

		if (_meshType == MeshType.None)
		{
			return false;
		}
		else if (_meshType == MeshType.HandLeft || _meshType == MeshType.HandRight)
		{
#if UNITY_EDITOR
			return OVRInput.IsControllerConnected(OVRInput.Controller.Hands);
#else
			return true;
#endif
		}
		else
		{
			return true;
		}
	}

	private void Initialize(MeshType meshType)
	{
		_mesh = new Mesh();

		var ovrpMesh = new OVRPlugin.Mesh();
		if (OVRPlugin.GetMesh((OVRPlugin.MeshType)_meshType, out ovrpMesh))
		{
			var vertices = new Vector3[ovrpMesh.NumVertices];
			for (int i = 0; i < ovrpMesh.NumVertices; ++i)
			{
				vertices[i] = ovrpMesh.VertexPositions[i].FromFlippedXVector3f();
			}
			_mesh.vertices = vertices;

			var uv = new Vector2[ovrpMesh.NumVertices];
			for (int i = 0; i < ovrpMesh.NumVertices; ++i)
			{
				uv[i] = new Vector2(ovrpMesh.VertexUV0[i].x, -ovrpMesh.VertexUV0[i].y);
			}
			_mesh.uv = uv;

			var triangles = new int[ovrpMesh.NumIndices];
			for (int i = 0; i < ovrpMesh.NumIndices; ++i)
			{
				triangles[i] = ovrpMesh.Indices[ovrpMesh.NumIndices - i - 1];
			}
			_mesh.triangles = triangles;

			var normals = new Vector3[ovrpMesh.NumVertices];
			for (int i = 0; i < ovrpMesh.NumVertices; ++i)
			{
				normals[i] = ovrpMesh.VertexNormals[i].FromFlippedXVector3f();
			}
			_mesh.normals = normals;

			var boneWeights = new BoneWeight[ovrpMesh.NumVertices];
			for (int i = 0; i < ovrpMesh.NumVertices; ++i)
			{
				var currentBlendWeight = ovrpMesh.BlendWeights[i];
				var currentBlendIndices = ovrpMesh.BlendIndices[i];

				boneWeights[i].boneIndex0 = (int)currentBlendIndices.x;
				boneWeights[i].weight0 = currentBlendWeight.x;
				boneWeights[i].boneIndex1 = (int)currentBlendIndices.y;
				boneWeights[i].weight1 = currentBlendWeight.y;
				boneWeights[i].boneIndex2 = (int)currentBlendIndices.z;
				boneWeights[i].weight2 = currentBlendWeight.z;
				boneWeights[i].boneIndex3 = (int)currentBlendIndices.w;
				boneWeights[i].weight3 = currentBlendWeight.w;
			}
			_mesh.boneWeights = boneWeights;

			IsInitialized = true;
		}
	}

#if UNITY_EDITOR
	private void Update()
	{
		if (ShouldInitialize())
		{
			Initialize(_meshType);
		}
	}
#endif

}