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

Licensed under the Oculus Utilities SDK License Version 1.31 (the "License"); you may not use
the Utilities SDK except in compliance with the License, which is provided at the time of installation
or download, or which otherwise accompanies this software in either electronic or hard copy form.

You may obtain a copy of the License at
https://developer.oculus.com/licenses/utilities-1.31

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(-70)]
public class OVRSkeletonRenderer : MonoBehaviour
{
	public interface IOVRSkeletonRendererDataProvider
	{
		SkeletonRendererData GetSkeletonRendererData();
	}

	public struct SkeletonRendererData
	{
		public float RootScale { get; set; }
		public bool IsDataValid { get; set; }
		public bool IsDataHighConfidence { get; set; }
		public bool ShouldUseSystemGestureMaterial { get; set; }
	}

	public enum ConfidenceBehavior
	{
		None,
		ToggleRenderer,
	}

	public enum SystemGestureBehavior
	{
		None,
		SwapMaterial,
	}

	[SerializeField]
	private IOVRSkeletonRendererDataProvider _dataProvider;
	[SerializeField]
	private ConfidenceBehavior _confidenceBehavior = ConfidenceBehavior.ToggleRenderer;
	[SerializeField]
	private SystemGestureBehavior _systemGestureBehavior = SystemGestureBehavior.SwapMaterial;
	[SerializeField]
	private bool _renderPhysicsCapsules = false;
	[SerializeField]
	private Material _skeletonMaterial;
	private Material _skeletonDefaultMaterial;
	[SerializeField]
	private Material _capsuleMaterial;
	private Material _capsuleDefaultMaterial;
	[SerializeField]
	private Material _systemGestureMaterial = null;
	private Material _systemGestureDefaultMaterial;

	private const float LINE_RENDERER_WIDTH = 0.005f;
	private List<BoneVisualization> _boneVisualizations;
	private List<CapsuleVisualization> _capsuleVisualizations;
	private OVRSkeleton _ovrSkeleton;
	private GameObject _skeletonGO;
	private float _scale;
	private static readonly Quaternion _capsuleRotationOffset = Quaternion.Euler(0, 0, 90);

	public bool IsInitialized { get; private set; }
	public bool IsDataValid { get; private set; }
	public bool IsDataHighConfidence { get; private set; }
	public bool ShouldUseSystemGestureMaterial { get; private set; }

	private class BoneVisualization
	{
		private GameObject BoneGO;
		private Transform BoneBegin;
		private Transform BoneEnd;
		private LineRenderer Line;
		private Material RenderMaterial;
		private Material SystemGestureMaterial;

		public BoneVisualization(GameObject rootGO,
				Material renderMat,
				Material systemGestureMat,
				float scale,
				Transform begin,
				Transform end)
		{
			RenderMaterial = renderMat;
			SystemGestureMaterial = systemGestureMat;

			BoneBegin = begin;
			BoneEnd = end;

			BoneGO = new GameObject(begin.name);
			BoneGO.transform.SetParent(rootGO.transform, false);

			Line = BoneGO.AddComponent<LineRenderer>();
			Line.sharedMaterial = RenderMaterial;
			Line.useWorldSpace = true;
			Line.positionCount = 2;

			Line.SetPosition(0, BoneBegin.position);
			Line.SetPosition(1, BoneEnd.position);

			Line.startWidth = LINE_RENDERER_WIDTH * scale;
			Line.endWidth = LINE_RENDERER_WIDTH * scale;
		}

		public void Update(float scale,
				bool shouldRender,
				bool shouldUseSystemGestureMaterial,
				ConfidenceBehavior confidenceBehavior,
				SystemGestureBehavior systemGestureBehavior)
		{
			Line.SetPosition(0, BoneBegin.position);
			Line.SetPosition(1, BoneEnd.position);

			Line.startWidth = LINE_RENDERER_WIDTH * scale;
			Line.endWidth = LINE_RENDERER_WIDTH * scale;

			if (confidenceBehavior == ConfidenceBehavior.ToggleRenderer)
			{
				Line.enabled = shouldRender;
			}

			if (systemGestureBehavior == SystemGestureBehavior.SwapMaterial)
			{
				if (shouldUseSystemGestureMaterial && Line.sharedMaterial != SystemGestureMaterial)
				{
					Line.sharedMaterial = SystemGestureMaterial;
				}
				else if (!shouldUseSystemGestureMaterial && Line.sharedMaterial != RenderMaterial)
				{
					Line.sharedMaterial = RenderMaterial;
				}
			}
		}
	}

	private class CapsuleVisualization
	{
		private GameObject CapsuleGO;
		private OVRBoneCapsule BoneCapsule;
		private Vector3 capsuleScale;
		private MeshRenderer Renderer;
		private Material RenderMaterial;
		private Material SystemGestureMaterial;

		public CapsuleVisualization(GameObject rootGO,
				Material renderMat,
				Material systemGestureMat,
				float scale,
				OVRBoneCapsule boneCapsule)
		{
			RenderMaterial = renderMat;
			SystemGestureMaterial = systemGestureMat;

			BoneCapsule = boneCapsule;
			
			CapsuleGO = GameObject.CreatePrimitive(PrimitiveType.Capsule);
			CapsuleCollider collider = CapsuleGO.GetComponent<CapsuleCollider>();
			Destroy(collider);
			Renderer = CapsuleGO.GetComponent<MeshRenderer>();
			Renderer.sharedMaterial = RenderMaterial;

			capsuleScale = Vector3.one;
			capsuleScale.y = boneCapsule.CapsuleCollider.height / 2;
			capsuleScale.x = boneCapsule.CapsuleCollider.radius * 2;
			capsuleScale.z = boneCapsule.CapsuleCollider.radius * 2;
			CapsuleGO.transform.localScale = capsuleScale * scale;
		}

		public void Update(float scale,
				bool shouldRender,
				bool shouldUseSystemGestureMaterial,
				ConfidenceBehavior confidenceBehavior,
				SystemGestureBehavior systemGestureBehavior)
		{
			if (confidenceBehavior == ConfidenceBehavior.ToggleRenderer)
			{
				if (CapsuleGO.activeSelf != shouldRender)
				{
					CapsuleGO.SetActive(shouldRender);
				}
			}
			
			CapsuleGO.transform.rotation = BoneCapsule.CapsuleCollider.transform.rotation * _capsuleRotationOffset;
			CapsuleGO.transform.position = BoneCapsule.CapsuleCollider.transform.TransformPoint(BoneCapsule.CapsuleCollider.center);
			CapsuleGO.transform.localScale = capsuleScale * scale;

			if (systemGestureBehavior == SystemGestureBehavior.SwapMaterial)
			{
				if (shouldUseSystemGestureMaterial && Renderer.sharedMaterial != SystemGestureMaterial)
				{
					Renderer.sharedMaterial = SystemGestureMaterial;
				}
				else if (!shouldUseSystemGestureMaterial && Renderer.sharedMaterial != RenderMaterial)
				{
					Renderer.sharedMaterial = RenderMaterial;
				}
			}
		}
	}

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

		if (_ovrSkeleton == null)
		{
			_ovrSkeleton = GetComponent<OVRSkeleton>();
		}
	}

	private void Start()
	{
		if (_ovrSkeleton == null)
		{
			this.enabled = false;
			return;
		}

		Initialize();
	}

	private void Initialize()
	{
		_boneVisualizations = new List<BoneVisualization>();
		_capsuleVisualizations = new List<CapsuleVisualization>();
		_ovrSkeleton = GetComponent<OVRSkeleton>();
		_skeletonGO = new GameObject("SkeletonRenderer");
		_skeletonGO.transform.SetParent(transform, false);

		if (_skeletonMaterial == null)
		{
			_skeletonDefaultMaterial = new Material(Shader.Find("Diffuse"));
			_skeletonMaterial = _skeletonDefaultMaterial;
		}

		if (_capsuleMaterial == null)
		{
			_capsuleDefaultMaterial = new Material(Shader.Find("Diffuse"));
			_capsuleMaterial = _capsuleDefaultMaterial;
		}

		if (_systemGestureMaterial == null)
		{
			_systemGestureDefaultMaterial = new Material(Shader.Find("Diffuse"));
			_systemGestureDefaultMaterial.color = Color.blue;
			_systemGestureMaterial = _systemGestureDefaultMaterial;
		}

		for (int i = 0; i < _ovrSkeleton.Bones.Count; i++)
		{
			var boneVis = new BoneVisualization(
				_skeletonGO,
				_skeletonMaterial,
				_systemGestureMaterial,
				_scale,
				_ovrSkeleton.Bones[i].Transform,
				_ovrSkeleton.Bones[i].Transform.parent);

			_boneVisualizations.Add(boneVis);
		}

		if (_renderPhysicsCapsules && _ovrSkeleton.Capsules != null)
		{
			for (int i = 0; i < _ovrSkeleton.Capsules.Count; i++)
			{
				var capsuleVis = new CapsuleVisualization(
					_skeletonGO,
					_capsuleMaterial,
					_systemGestureMaterial,
					_scale,
					_ovrSkeleton.Capsules[i]);

				_capsuleVisualizations.Add(capsuleVis);
			}
		}

		IsInitialized = true;
	}

	public void Update()
	{
		IsDataValid = false;
		IsDataHighConfidence = false;
		ShouldUseSystemGestureMaterial = false;

		if (IsInitialized)
		{
			bool shouldRender = false;

			if (_dataProvider != null)
			{
				var data = _dataProvider.GetSkeletonRendererData();

				IsDataValid = data.IsDataValid;
				IsDataHighConfidence = data.IsDataHighConfidence;
				ShouldUseSystemGestureMaterial = data.ShouldUseSystemGestureMaterial;

				shouldRender = data.IsDataValid && data.IsDataHighConfidence;

				if (data.IsDataValid)
				{
					_scale = data.RootScale;
				}
			}

			for (int i = 0; i < _boneVisualizations.Count; i++)
			{
				_boneVisualizations[i].Update(_scale, shouldRender, ShouldUseSystemGestureMaterial, _confidenceBehavior, _systemGestureBehavior);
			}

			for (int i = 0; i < _capsuleVisualizations.Count; i++)
			{
				_capsuleVisualizations[i].Update(_scale, shouldRender, ShouldUseSystemGestureMaterial, _confidenceBehavior, _systemGestureBehavior);
			}
		}
	}

	private void OnDestroy()
	{
		if (_skeletonDefaultMaterial != null)
		{
			DestroyImmediate(_skeletonDefaultMaterial, false);
		}

		if (_capsuleDefaultMaterial != null)
		{
			DestroyImmediate(_capsuleDefaultMaterial, false);
		}

		if (_systemGestureDefaultMaterial != null)
		{
			DestroyImmediate(_systemGestureDefaultMaterial, false);
		}
	}
}