//======= Copyright (c) Valve Corporation, All rights reserved. ===============
//
// Purpose: Displays text and button hints on the controllers
//
//=============================================================================

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

namespace Valve.VR.InteractionSystem
{
	//-------------------------------------------------------------------------
	public class ControllerButtonHints : MonoBehaviour
	{
		public Material controllerMaterial;
		public Color flashColor = new Color( 1.0f, 0.557f, 0.0f );
		public GameObject textHintPrefab;

		[Header( "Debug" )]
		public bool debugHints = false;

		private SteamVR_RenderModel renderModel;
		private Player player;

		private List<MeshRenderer> renderers = new List<MeshRenderer>();
		private List<MeshRenderer> flashingRenderers = new List<MeshRenderer>();
		private float startTime;
		private float tickCount;

		private enum OffsetType
		{
			Up,
			Right,
			Forward,
			Back
		}

		//Info for each of the buttons
		private class ButtonHintInfo
		{
			public string componentName;
			public List<MeshRenderer> renderers;
			public Transform localTransform;

			//Text hint
			public GameObject textHintObject;
			public Transform textStartAnchor;
			public Transform textEndAnchor;
			public Vector3 textEndOffsetDir;
			public Transform canvasOffset;

			public Text text;
			public TextMesh textMesh;
			public Canvas textCanvas;
			public LineRenderer line;

			public float distanceFromCenter;
			public bool textHintActive = false;
		}

		private Dictionary<EVRButtonId, ButtonHintInfo> buttonHintInfos;
		private Transform textHintParent;
		private List<KeyValuePair<string, ulong>> componentButtonMasks = new List<KeyValuePair<string, ulong>>();

		private int colorID;

		public bool initialized { get; private set; }
		private Vector3 centerPosition = Vector3.zero;

		SteamVR_Events.Action renderModelLoadedAction;

		
		//-------------------------------------------------
		void Awake()
		{
			renderModelLoadedAction = SteamVR_Events.RenderModelLoadedAction( OnRenderModelLoaded );
			colorID = Shader.PropertyToID( "_Color" );
		}


		//-------------------------------------------------
		void Start()
		{
			player = Player.instance;
		}


		//-------------------------------------------------
		private void HintDebugLog( string msg )
		{
			if ( debugHints )
			{
				Debug.Log( "Hints: " + msg );
			}
		}


		//-------------------------------------------------
		void OnEnable()
		{
			renderModelLoadedAction.enabled = true;
		}


		//-------------------------------------------------
		void OnDisable()
		{
			renderModelLoadedAction.enabled = false;
			Clear();
		}


		//-------------------------------------------------
		private void OnParentHandInputFocusLost()
		{
			//Hide all the hints when the controller is no longer the primary attached object
			HideAllButtonHints();
			HideAllText();
		}


		//-------------------------------------------------
		// Gets called when the hand has been initialized and a render model has been set
		//-------------------------------------------------
		private void OnHandInitialized( int deviceIndex )
		{
			//Create a new render model for the controller hints
			renderModel = new GameObject( "SteamVR_RenderModel" ).AddComponent<SteamVR_RenderModel>();
			renderModel.transform.parent = transform;
			renderModel.transform.localPosition = Vector3.zero;
			renderModel.transform.localRotation = Quaternion.identity;
			renderModel.transform.localScale = Vector3.one;
			renderModel.SetDeviceIndex( deviceIndex );

			if ( !initialized )
			{
				//The controller hint render model needs to be active to get accurate transforms for all the individual components
				renderModel.gameObject.SetActive( true );
			}
		}


		//-------------------------------------------------
		void OnRenderModelLoaded( SteamVR_RenderModel renderModel, bool succeess )
		{
			//Only initialize when the render model for the controller hints has been loaded
			if ( renderModel == this.renderModel )
			{
				textHintParent = new GameObject( "Text Hints" ).transform;
				textHintParent.SetParent( this.transform );
				textHintParent.localPosition = Vector3.zero;
				textHintParent.localRotation = Quaternion.identity;
				textHintParent.localScale = Vector3.one;

				//Get the button mask for each component of the render model
				using ( var holder = new SteamVR_RenderModel.RenderModelInterfaceHolder() )
				{
					var renderModels = holder.instance;
					if ( renderModels != null )
					{
						string renderModelDebug = "Components for render model " + renderModel.index;
						foreach ( Transform child in renderModel.transform )
						{
							ulong buttonMask = renderModels.GetComponentButtonMask( renderModel.renderModelName, child.name );

							componentButtonMasks.Add( new KeyValuePair<string, ulong>( child.name, buttonMask ) );

							renderModelDebug += "\n\t" + child.name + ": " + buttonMask;
						}

						//Uncomment to show the button mask for each component of the render model
						HintDebugLog( renderModelDebug );
					}
				}

				buttonHintInfos = new Dictionary<EVRButtonId, ButtonHintInfo>();

				CreateAndAddButtonInfo( EVRButtonId.k_EButton_SteamVR_Trigger );
				CreateAndAddButtonInfo( EVRButtonId.k_EButton_ApplicationMenu );
				CreateAndAddButtonInfo( EVRButtonId.k_EButton_System );
				CreateAndAddButtonInfo( EVRButtonId.k_EButton_Grip );
				CreateAndAddButtonInfo( EVRButtonId.k_EButton_SteamVR_Touchpad );
				CreateAndAddButtonInfo( EVRButtonId.k_EButton_A );

				ComputeTextEndTransforms();

				initialized = true;

				//Set the controller hints render model to not active
				renderModel.gameObject.SetActive( false );
			}
		}


		//-------------------------------------------------
		private void CreateAndAddButtonInfo( EVRButtonId buttonID )
		{
			Transform buttonTransform = null;
			List<MeshRenderer> buttonRenderers = new List<MeshRenderer>();

			string buttonDebug = "Looking for button: " + buttonID;

			EVRButtonId searchButtonID = buttonID;
			if ( buttonID == EVRButtonId.k_EButton_Grip && SteamVR.instance.hmd_TrackingSystemName.ToLowerInvariant().Contains( "oculus" ) )
			{
				searchButtonID = EVRButtonId.k_EButton_Axis2;
			}
			ulong buttonMaskForID = ( 1ul << (int)searchButtonID );

			foreach ( KeyValuePair<string, ulong> componentButtonMask in componentButtonMasks )
			{
				if ( ( componentButtonMask.Value & buttonMaskForID ) == buttonMaskForID )
				{
					buttonDebug += "\nFound component: " + componentButtonMask.Key + " " + componentButtonMask.Value;
					Transform componentTransform = renderModel.FindComponent( componentButtonMask.Key );

					buttonTransform = componentTransform;

					buttonDebug += "\nFound componentTransform: " + componentTransform + " buttonTransform: " + buttonTransform;

					buttonRenderers.AddRange( componentTransform.GetComponentsInChildren<MeshRenderer>() );
				}
			}

			buttonDebug += "\nFound " + buttonRenderers.Count + " renderers for " + buttonID;
			foreach ( MeshRenderer renderer in buttonRenderers )
			{
				buttonDebug += "\n\t" + renderer.name;
			}

			HintDebugLog( buttonDebug );

			if ( buttonTransform == null )
			{
				HintDebugLog( "Couldn't find buttonTransform for " + buttonID );
				return;
			}

			ButtonHintInfo hintInfo = new ButtonHintInfo();
			buttonHintInfos.Add( buttonID, hintInfo );

			hintInfo.componentName = buttonTransform.name;
			hintInfo.renderers = buttonRenderers;

			//Get the local transform for the button
			hintInfo.localTransform = buttonTransform.Find( SteamVR_RenderModel.k_localTransformName );

			OffsetType offsetType = OffsetType.Right;
			switch ( buttonID )
			{
				case EVRButtonId.k_EButton_SteamVR_Trigger:
					{
						offsetType = OffsetType.Right;
					}
					break;
				case EVRButtonId.k_EButton_ApplicationMenu:
					{
						offsetType = OffsetType.Right;
					}
					break;
				case EVRButtonId.k_EButton_System:
					{
						offsetType = OffsetType.Right;
					}
					break;
				case Valve.VR.EVRButtonId.k_EButton_Grip:
					{
						offsetType = OffsetType.Forward;
					}
					break;
				case Valve.VR.EVRButtonId.k_EButton_SteamVR_Touchpad:
					{
						offsetType = OffsetType.Up;
					}
					break;
			}

			//Offset for the text end transform
			switch ( offsetType )
			{
				case OffsetType.Forward:
					hintInfo.textEndOffsetDir = hintInfo.localTransform.forward;
					break;
				case OffsetType.Back:
					hintInfo.textEndOffsetDir = -hintInfo.localTransform.forward;
					break;
				case OffsetType.Right:
					hintInfo.textEndOffsetDir = hintInfo.localTransform.right;
					break;
				case OffsetType.Up:
					hintInfo.textEndOffsetDir = hintInfo.localTransform.up;
					break;
			}

			//Create the text hint object
			Vector3 hintStartPos = hintInfo.localTransform.position + ( hintInfo.localTransform.forward * 0.01f );
			hintInfo.textHintObject = GameObject.Instantiate( textHintPrefab, hintStartPos, Quaternion.identity ) as GameObject;
			hintInfo.textHintObject.name = "Hint_" + hintInfo.componentName + "_Start";
			hintInfo.textHintObject.transform.SetParent( textHintParent );
			hintInfo.textHintObject.layer = gameObject.layer;
			hintInfo.textHintObject.tag = gameObject.tag;

			//Get all the relevant child objects
			hintInfo.textStartAnchor = hintInfo.textHintObject.transform.Find( "Start" );
			hintInfo.textEndAnchor = hintInfo.textHintObject.transform.Find( "End" );
			hintInfo.canvasOffset = hintInfo.textHintObject.transform.Find( "CanvasOffset" );
			hintInfo.line = hintInfo.textHintObject.transform.Find( "Line" ).GetComponent<LineRenderer>();
			hintInfo.textCanvas = hintInfo.textHintObject.GetComponentInChildren<Canvas>();
			hintInfo.text = hintInfo.textCanvas.GetComponentInChildren<Text>();
			hintInfo.textMesh = hintInfo.textCanvas.GetComponentInChildren<TextMesh>();

			hintInfo.textHintObject.SetActive( false );

			hintInfo.textStartAnchor.position = hintStartPos;

			if ( hintInfo.text != null )
			{
				hintInfo.text.text = hintInfo.componentName;
			}

			if ( hintInfo.textMesh != null )
			{
				hintInfo.textMesh.text = hintInfo.componentName;
			}

			centerPosition += hintInfo.textStartAnchor.position;

			// Scale hint components to match player size
			hintInfo.textCanvas.transform.localScale = Vector3.Scale( hintInfo.textCanvas.transform.localScale, player.transform.localScale );
			hintInfo.textStartAnchor.transform.localScale = Vector3.Scale( hintInfo.textStartAnchor.transform.localScale, player.transform.localScale );
			hintInfo.textEndAnchor.transform.localScale = Vector3.Scale( hintInfo.textEndAnchor.transform.localScale, player.transform.localScale );
			hintInfo.line.transform.localScale = Vector3.Scale( hintInfo.line.transform.localScale, player.transform.localScale );
		}


		//-------------------------------------------------
		private void ComputeTextEndTransforms()
		{
			//This is done as a separate step after all the ButtonHintInfos have been initialized
			//to make the text hints fan out appropriately based on the button's position on the controller.

			centerPosition /= buttonHintInfos.Count;
			float maxDistanceFromCenter = 0.0f;

			foreach ( var hintInfo in buttonHintInfos )
			{
				hintInfo.Value.distanceFromCenter = Vector3.Distance( hintInfo.Value.textStartAnchor.position, centerPosition );

				if ( hintInfo.Value.distanceFromCenter > maxDistanceFromCenter )
				{
					maxDistanceFromCenter = hintInfo.Value.distanceFromCenter;
				}
			}

			foreach ( var hintInfo in buttonHintInfos )
			{
				Vector3 centerToButton = hintInfo.Value.textStartAnchor.position - centerPosition;
				centerToButton.Normalize();

				centerToButton = Vector3.Project( centerToButton, renderModel.transform.forward );

				//Spread out the text end positions based on the distance from the center
				float t = hintInfo.Value.distanceFromCenter / maxDistanceFromCenter;
				float scale = hintInfo.Value.distanceFromCenter * Mathf.Pow( 2, 10 * ( t - 1.0f ) ) * 20.0f;

				//Flip the direction of the end pos based on which hand this is
				float endPosOffset = 0.1f;

				Vector3 hintEndPos = hintInfo.Value.textStartAnchor.position + ( hintInfo.Value.textEndOffsetDir * endPosOffset ) + ( centerToButton * scale * 0.1f );
				hintInfo.Value.textEndAnchor.position = hintEndPos;

				hintInfo.Value.canvasOffset.position = hintEndPos;
				hintInfo.Value.canvasOffset.localRotation = Quaternion.identity;
			}
		}


		//-------------------------------------------------
		private void ShowButtonHint( params EVRButtonId[] buttons )
		{
			renderModel.gameObject.SetActive( true );

			renderModel.GetComponentsInChildren<MeshRenderer>( renderers );
			for ( int i = 0; i < renderers.Count; i++ )
			{
				Texture mainTexture = renderers[i].material.mainTexture;
				renderers[i].sharedMaterial = controllerMaterial;
				renderers[i].material.mainTexture = mainTexture;

				// This is to poke unity into setting the correct render queue for the model
				renderers[i].material.renderQueue = controllerMaterial.shader.renderQueue;
			}

			for ( int i = 0; i < buttons.Length; i++ )
			{
				if ( buttonHintInfos.ContainsKey( buttons[i] ) )
				{
					ButtonHintInfo hintInfo = buttonHintInfos[buttons[i]];
					foreach ( MeshRenderer renderer in hintInfo.renderers )
					{
						if ( !flashingRenderers.Contains( renderer ) )
						{
							flashingRenderers.Add( renderer );
						}
					}
				}
			}

			startTime = Time.realtimeSinceStartup;
			tickCount = 0.0f;
		}


		//-------------------------------------------------
		private void HideAllButtonHints()
		{
			Clear();

			renderModel.gameObject.SetActive( false );
		}


		//-------------------------------------------------
		private void HideButtonHint( params EVRButtonId[] buttons )
		{
			Color baseColor = controllerMaterial.GetColor( colorID );
			for ( int i = 0; i < buttons.Length; i++ )
			{
				if ( buttonHintInfos.ContainsKey( buttons[i] ) )
				{
					ButtonHintInfo hintInfo = buttonHintInfos[buttons[i]];
					foreach ( MeshRenderer renderer in hintInfo.renderers )
					{
						renderer.material.color = baseColor;
						flashingRenderers.Remove( renderer );
					}
				}
			}

			if ( flashingRenderers.Count == 0 )
			{
				renderModel.gameObject.SetActive( false );
			}
		}




		//-------------------------------------------------
		private bool IsButtonHintActive( EVRButtonId button )
		{
			if ( buttonHintInfos.ContainsKey( button ) )
			{
				ButtonHintInfo hintInfo = buttonHintInfos[button];
				foreach ( MeshRenderer buttonRenderer in hintInfo.renderers )
				{
					if ( flashingRenderers.Contains( buttonRenderer ) )
					{
						return true;
					}
				}
			}

			return false;
		}


		//-------------------------------------------------
		private IEnumerator TestButtonHints()
		{
			while ( true )
			{
				ShowButtonHint( EVRButtonId.k_EButton_SteamVR_Trigger );
				yield return new WaitForSeconds( 1.0f );
				ShowButtonHint( EVRButtonId.k_EButton_ApplicationMenu );
				yield return new WaitForSeconds( 1.0f );
				ShowButtonHint( EVRButtonId.k_EButton_System );
				yield return new WaitForSeconds( 1.0f );
				ShowButtonHint( EVRButtonId.k_EButton_Grip );
				yield return new WaitForSeconds( 1.0f );
				ShowButtonHint( EVRButtonId.k_EButton_SteamVR_Touchpad );
				yield return new WaitForSeconds( 1.0f );
			}
		}


		//-------------------------------------------------
		private IEnumerator TestTextHints()
		{
			while ( true )
			{
				ShowText( EVRButtonId.k_EButton_SteamVR_Trigger, "Trigger" );
				yield return new WaitForSeconds( 3.0f );
				ShowText( EVRButtonId.k_EButton_ApplicationMenu, "Application" );
				yield return new WaitForSeconds( 3.0f );
				ShowText( EVRButtonId.k_EButton_System, "System" );
				yield return new WaitForSeconds( 3.0f );
				ShowText( EVRButtonId.k_EButton_Grip, "Grip" );
				yield return new WaitForSeconds( 3.0f );
				ShowText( EVRButtonId.k_EButton_SteamVR_Touchpad, "Touchpad" );
				yield return new WaitForSeconds( 3.0f );

				HideAllText();
				yield return new WaitForSeconds( 3.0f );
			}
		}


		//-------------------------------------------------
		void Update()
		{
			if ( renderModel != null && renderModel.gameObject.activeInHierarchy && flashingRenderers.Count > 0 )
			{
				Color baseColor = controllerMaterial.GetColor( colorID );

				float flash = ( Time.realtimeSinceStartup - startTime ) * Mathf.PI * 2.0f;
				flash = Mathf.Cos( flash );
				flash = Util.RemapNumberClamped( flash, -1.0f, 1.0f, 0.0f, 1.0f );

				float ticks = ( Time.realtimeSinceStartup - startTime );
				if ( ticks - tickCount > 1.0f )
				{
					tickCount += 1.0f;
					SteamVR_Controller.Device device = SteamVR_Controller.Input( (int)renderModel.index );
					if ( device != null )
					{
						device.TriggerHapticPulse();
					}
				}

				for ( int i = 0; i < flashingRenderers.Count; i++ )
				{
					Renderer r = flashingRenderers[i];
					r.material.SetColor( colorID, Color.Lerp( baseColor, flashColor, flash ) );
				}

				if ( initialized )
				{
					foreach ( var hintInfo in buttonHintInfos )
					{
						if ( hintInfo.Value.textHintActive )
						{
							UpdateTextHint( hintInfo.Value );
						}
					}
				}
			}
		}


		//-------------------------------------------------
		private void UpdateTextHint( ButtonHintInfo hintInfo )
		{
			Transform playerTransform = player.hmdTransform;
			Vector3 vDir = playerTransform.position - hintInfo.canvasOffset.position;

			Quaternion standardLookat = Quaternion.LookRotation( vDir, Vector3.up );
			Quaternion upsideDownLookat = Quaternion.LookRotation( vDir, playerTransform.up );

			float flInterp;
			if ( playerTransform.forward.y > 0.0f )
			{
				flInterp = Util.RemapNumberClamped( playerTransform.forward.y, 0.6f, 0.4f, 1.0f, 0.0f );
			}
			else
			{
				flInterp = Util.RemapNumberClamped( playerTransform.forward.y, -0.8f, -0.6f, 1.0f, 0.0f );
			}

			hintInfo.canvasOffset.rotation = Quaternion.Slerp( standardLookat, upsideDownLookat, flInterp );

			Transform lineTransform = hintInfo.line.transform;

			hintInfo.line.useWorldSpace = false;
			hintInfo.line.SetPosition( 0, lineTransform.InverseTransformPoint( hintInfo.textStartAnchor.position ) );
			hintInfo.line.SetPosition( 1, lineTransform.InverseTransformPoint( hintInfo.textEndAnchor.position ) );
		}


		//-------------------------------------------------
		private void Clear()
		{
			renderers.Clear();
			flashingRenderers.Clear();
		}


		//-------------------------------------------------
		private void ShowText( EVRButtonId button, string text, bool highlightButton = true )
		{
			if ( buttonHintInfos.ContainsKey( button ) )
			{
				ButtonHintInfo hintInfo = buttonHintInfos[button];
				hintInfo.textHintObject.SetActive( true );
				hintInfo.textHintActive = true;

				if ( hintInfo.text != null )
				{
					hintInfo.text.text = text;
				}

				if ( hintInfo.textMesh != null )
				{
					hintInfo.textMesh.text = text;
				}

				UpdateTextHint( hintInfo );

				if ( highlightButton )
				{
					ShowButtonHint( button );
				}

				renderModel.gameObject.SetActive( true );
			}
		}


		//-------------------------------------------------
		private void HideText( EVRButtonId button )
		{
			if ( buttonHintInfos.ContainsKey( button ) )
			{
				ButtonHintInfo hintInfo = buttonHintInfos[button];
				hintInfo.textHintObject.SetActive( false );
				hintInfo.textHintActive = false;

				HideButtonHint( button );
			}
		}


		//-------------------------------------------------
		private void HideAllText()
		{
			foreach ( var hintInfo in buttonHintInfos )
			{
				hintInfo.Value.textHintObject.SetActive( false );
				hintInfo.Value.textHintActive = false;
			}

			HideAllButtonHints();
		}


		//-------------------------------------------------
		private string GetActiveHintText( EVRButtonId button )
		{
			if ( buttonHintInfos.ContainsKey( button ) )
			{
				ButtonHintInfo hintInfo = buttonHintInfos[button];
				if ( hintInfo.textHintActive )
				{
					return hintInfo.text.text;
				}
			}
			return string.Empty;
		}


		//-------------------------------------------------
		// These are the static functions which are used to show/hide the hints
		//-------------------------------------------------

		//-------------------------------------------------
		private static ControllerButtonHints GetControllerButtonHints( Hand hand )
		{
			if ( hand != null )
			{
				ControllerButtonHints hints = hand.GetComponentInChildren<ControllerButtonHints>();
				if ( hints != null && hints.initialized )
				{
					return hints;
				}
			}

			return null;
		}


		//-------------------------------------------------
		public static void ShowButtonHint( Hand hand, params EVRButtonId[] buttons )
		{
			ControllerButtonHints hints = GetControllerButtonHints( hand );
			if ( hints != null )
			{
				hints.ShowButtonHint( buttons );
			}
		}


		//-------------------------------------------------
		public static void HideButtonHint( Hand hand, params EVRButtonId[] buttons )
		{
			ControllerButtonHints hints = GetControllerButtonHints( hand );
			if ( hints != null )
			{
				hints.HideButtonHint( buttons );
			}
		}


		//-------------------------------------------------
		public static void HideAllButtonHints( Hand hand )
		{
			ControllerButtonHints hints = GetControllerButtonHints( hand );
			if ( hints != null )
			{
				hints.HideAllButtonHints();
			}
		}


		//-------------------------------------------------
		public static bool IsButtonHintActive( Hand hand, EVRButtonId button )
		{
			ControllerButtonHints hints = GetControllerButtonHints( hand );
			if ( hints != null )
			{
				return hints.IsButtonHintActive( button );
			}

			return false;
		}


		//-------------------------------------------------
		public static void ShowTextHint( Hand hand, EVRButtonId button, string text, bool highlightButton = true )
		{
			ControllerButtonHints hints = GetControllerButtonHints( hand );
			if ( hints != null )
			{
				hints.ShowText( button, text, highlightButton );
			}
		}


		//-------------------------------------------------
		public static void HideTextHint( Hand hand, EVRButtonId button )
		{
			ControllerButtonHints hints = GetControllerButtonHints( hand );
			if ( hints != null )
			{
				hints.HideText( button );
			}
		}


		//-------------------------------------------------
		public static void HideAllTextHints( Hand hand )
		{
			ControllerButtonHints hints = GetControllerButtonHints( hand );
			if ( hints != null )
			{
				hints.HideAllText();
			}
		}


		//-------------------------------------------------
		public static string GetActiveHintText( Hand hand, EVRButtonId button )
		{
			ControllerButtonHints hints = GetControllerButtonHints( hand );
			if ( hints != null )
			{
				return hints.GetActiveHintText( button );
			}

			return string.Empty;
		}
	}
}