/************************************************************************************

Copyright   :   Copyright 2017 Oculus VR, LLC. All Rights reserved.

Licensed under the Oculus VR Rift SDK License Version 3.4.1 (the "License");
you may not use the Oculus VR Rift 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/sdk-3.4.1

Unless required by applicable law or agreed to in writing, the Oculus VR 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 UnityEngine;
using System.Collections;
using UnityEngine.UI;

//-------------------------------------------------------------------------------------
/// <summary>
/// Shows debug information on a heads-up display.
/// </summary>
public class OVRDebugInfo : MonoBehaviour
{
    #region GameObjects for Debug Information UIs   
    GameObject debugUIManager;
    GameObject debugUIObject;
    GameObject riftPresent;    
    GameObject fps;    
    GameObject ipd;
    GameObject fov;
    GameObject height;
	GameObject depth;
	GameObject resolutionEyeTexture;
    GameObject latencies;
    GameObject texts;    
    #endregion

    #region Debug strings
	string strRiftPresent            = null; // "VR DISABLED"
    string strFPS                    = null; // "FPS: 0";
    string strIPD                    = null; // "IPD: 0.000";
    string strFOV                    = null; // "FOV: 0.0f";
    string strHeight                 = null; // "Height: 0.0f";
	string strDepth                  = null; // "Depth: 0.0f";
	string strResolutionEyeTexture   = null; // "Resolution : {0} x {1}"
    string strLatencies              = null; // "R: {0:F3} TW: {1:F3} PP: {2:F3} RE: {3:F3} TWE: {4:F3}"
    #endregion

    /// <summary>
    /// Variables for FPS
    /// </summary>
    float updateInterval = 0.5f;
    float accum          = 0.0f;
    int   frames         = 0;
    float timeLeft       = 0.0f;

    /// <summary>
    /// Managing for UI initialization
    /// </summary>
    bool  initUIComponent = false;
    bool  isInited        = false;

    /// <summary>
    /// UIs Y offset
    /// </summary>
    float offsetY = 55.0f;

    /// <summary>
    /// Managing for rift detection UI
    /// </summary>
    float riftPresentTimeout = 0.0f;

    /// <summary>
    /// Turn on / off VR variables
    /// </summary>
    bool showVRVars = false;

    #region MonoBehaviour handler

    /// <summary>
    /// Initialization
    /// </summary>
    void Awake()
    {
        // Create canvas for using new GUI
        debugUIManager = new GameObject();
        debugUIManager.name = "DebugUIManager";
        debugUIManager.transform.parent = GameObject.Find("LeftEyeAnchor").transform;

        RectTransform rectTransform = debugUIManager.AddComponent<RectTransform>();
        rectTransform.sizeDelta = new Vector2(100f, 100f);
        rectTransform.localScale = new Vector3(0.001f, 0.001f, 0.001f);
        rectTransform.localPosition = new Vector3(0.01f, 0.17f, 0.53f);
        rectTransform.localEulerAngles = Vector3.zero;

        Canvas canvas = debugUIManager.AddComponent<Canvas>();
        canvas.renderMode = RenderMode.WorldSpace;
        canvas.pixelPerfect = false;
    }

    /// <summary>
    /// Updating VR variables and managing UI present
    /// </summary>
    void Update()
    {
        if (initUIComponent && !isInited)
        {
            InitUIComponents();
        }

        if (Input.GetKeyDown(KeyCode.Space) && riftPresentTimeout < 0.0f)
        {
            initUIComponent = true;
            showVRVars ^= true;
        }

        UpdateDeviceDetection();

        // Presenting VR variables
        if (showVRVars)
        {
            debugUIManager.SetActive(true);
            UpdateVariable();
            UpdateStrings();           
        }
        else
        {
            debugUIManager.SetActive(false);
        }
    }

    /// <summary>
    /// Initialize isInited value on OnDestroy
    /// </summary>
    void OnDestroy()
    {
        isInited = false;
    }
    #endregion

    #region Private Functions
    /// <summary>
    /// Initialize UI GameObjects
    /// </summary>
    void InitUIComponents()
    {
        float posY = 0.0f;
        int fontSize = 20;

        debugUIObject = new GameObject();
        debugUIObject.name = "DebugInfo";
        debugUIObject.transform.parent = GameObject.Find("DebugUIManager").transform;
        debugUIObject.transform.localPosition = new Vector3(0.0f, 100.0f, 0.0f);
        debugUIObject.transform.localEulerAngles = Vector3.zero;
        debugUIObject.transform.localScale = new Vector3(1.0f, 1.0f, 1.0f);

        // Print out for FPS
        if (!string.IsNullOrEmpty(strFPS))
        {
            fps = VariableObjectManager(fps, "FPS", posY -= offsetY, strFPS, fontSize);
        }

        // Print out for IPD
        if (!string.IsNullOrEmpty(strIPD))
        {
            ipd = VariableObjectManager(ipd, "IPD", posY -= offsetY, strIPD, fontSize);
        }

        // Print out for FOV
        if (!string.IsNullOrEmpty(strFOV))
        {
            fov = VariableObjectManager(fov, "FOV", posY -= offsetY, strFOV, fontSize);
        }

        // Print out for Height
        if (!string.IsNullOrEmpty(strHeight))
        {
            height = VariableObjectManager(height, "Height", posY -= offsetY, strHeight, fontSize);
        }
		
		// Print out for Depth
		if (!string.IsNullOrEmpty(strDepth))
		{
			depth = VariableObjectManager(depth, "Depth", posY -= offsetY, strDepth, fontSize);
		}

		// Print out for Resoulution of Eye Texture
        if (!string.IsNullOrEmpty(strResolutionEyeTexture))
        {
            resolutionEyeTexture = VariableObjectManager(resolutionEyeTexture, "Resolution", posY -= offsetY, strResolutionEyeTexture, fontSize);
        }

        // Print out for Latency
        if (!string.IsNullOrEmpty(strLatencies))
        {
            latencies = VariableObjectManager(latencies, "Latency", posY -= offsetY, strLatencies, 17);
            posY = 0.0f;
        }

        initUIComponent = false;
        isInited = true;

    }

    /// <summary>
    /// Update VR Variables
    /// </summary>
    void UpdateVariable()
    {        
        UpdateIPD();
        UpdateEyeHeightOffset();
		UpdateEyeDepthOffset();
		UpdateFOV();
        UpdateResolutionEyeTexture();
        UpdateLatencyValues();
        UpdateFPS();       
    }

    /// <summary>
    /// Update Strings
    /// </summary>
    void UpdateStrings()
    {
        if (debugUIObject == null)
            return;       
                
        if (!string.IsNullOrEmpty(strFPS))
            fps.GetComponentInChildren<Text>().text = strFPS;
        if (!string.IsNullOrEmpty(strIPD))
            ipd.GetComponentInChildren<Text>().text = strIPD;
        if (!string.IsNullOrEmpty(strFOV))
            fov.GetComponentInChildren<Text>().text = strFOV;
        if (!string.IsNullOrEmpty(strResolutionEyeTexture))
            resolutionEyeTexture.GetComponentInChildren<Text>().text = strResolutionEyeTexture;
        if (!string.IsNullOrEmpty(strLatencies))
		{
            latencies.GetComponentInChildren<Text>().text = strLatencies;
			latencies.GetComponentInChildren<Text>().fontSize = 14;
		}
        if (!string.IsNullOrEmpty(strHeight))
            height.GetComponentInChildren<Text>().text = strHeight;
		if (!string.IsNullOrEmpty(strDepth))
			depth.GetComponentInChildren<Text>().text = strDepth;
	}
	
	/// <summary>
    /// It's for rift present GUI
    /// </summary>
    void RiftPresentGUI(GameObject guiMainOBj)
    {
        riftPresent = ComponentComposition(riftPresent);
        riftPresent.transform.SetParent(guiMainOBj.transform);
        riftPresent.name = "RiftPresent";
        RectTransform rectTransform = riftPresent.GetComponent<RectTransform>();
        rectTransform.localPosition = new Vector3(0.0f, 0.0f, 0.0f);
        rectTransform.localScale = new Vector3(1.0f, 1.0f, 1.0f);
        rectTransform.localEulerAngles = Vector3.zero;

        Text text = riftPresent.GetComponentInChildren<Text>();
        text.text = strRiftPresent;
        text.fontSize = 20;
    }

    /// <summary>
    /// Updates the device detection.
    /// </summary>
    void UpdateDeviceDetection()
    {
        if (riftPresentTimeout >= 0.0f)
        {
            riftPresentTimeout -= Time.deltaTime;
        }
    }

    /// <summary>
    /// Object Manager for Variables
    /// </summary>
    /// <returns> gameobject for each Variable </returns>
    GameObject VariableObjectManager(GameObject gameObject, string name, float posY, string str, int fontSize)
    {
        gameObject = ComponentComposition(gameObject);
        gameObject.name = name;
        gameObject.transform.SetParent(debugUIObject.transform);

        RectTransform rectTransform = gameObject.GetComponent<RectTransform>();
        rectTransform.localPosition = new Vector3(0.0f, posY -= offsetY, 0.0f);

        Text text = gameObject.GetComponentInChildren<Text>();
        text.text = str;
        text.fontSize = fontSize;
        gameObject.transform.localEulerAngles = Vector3.zero;

        rectTransform.localScale = new Vector3(1.0f, 1.0f, 1.0f);

        return gameObject;
    }

    /// <summary>
    /// Component composition
    /// </summary>
    /// <returns> Composed gameobject. </returns>
    GameObject ComponentComposition(GameObject GO)
    {
        GO = new GameObject();
        GO.AddComponent<RectTransform>();
        GO.AddComponent<CanvasRenderer>();
        GO.AddComponent<Image>();
        GO.GetComponent<RectTransform>().sizeDelta = new Vector2(350f, 50f);
        GO.GetComponent<Image>().color = new Color(7f / 255f, 45f / 255f, 71f / 255f, 200f / 255f);

        texts = new GameObject();
        texts.AddComponent<RectTransform>();
        texts.AddComponent<CanvasRenderer>();
        texts.AddComponent<Text>();
        texts.GetComponent<RectTransform>().sizeDelta = new Vector2(350f, 50f);
		texts.GetComponent<Text>().font = Resources.GetBuiltinResource(typeof(Font), "Arial.ttf") as Font;
        texts.GetComponent<Text>().alignment = TextAnchor.MiddleCenter;

        texts.transform.SetParent(GO.transform);
        texts.name = "TextBox";

        return GO;
    }
    #endregion

    #region Debugging variables handler
    /// <summary>
    /// Updates the IPD.
    /// </summary>
    void UpdateIPD()
    {
        strIPD = System.String.Format("IPD (mm): {0:F4}", OVRManager.profile.ipd * 1000.0f);
    }

    /// <summary>
    /// Updates the eye height offset.
    /// </summary>
    void UpdateEyeHeightOffset()
    {
        float eyeHeight = OVRManager.profile.eyeHeight;
        strHeight = System.String.Format("Eye Height (m): {0:F3}", eyeHeight);
	}
	
	/// <summary>
	/// Updates the eye depth offset.
	/// </summary>
	void UpdateEyeDepthOffset()
	{
		float eyeDepth = OVRManager.profile.eyeDepth;
		strDepth = System.String.Format("Eye Depth (m): {0:F3}", eyeDepth);
	}
	
	/// <summary>
	/// Updates the FOV.
    /// </summary>
    void UpdateFOV()
    {
#if UNITY_2017_2_OR_NEWER
        OVRDisplay.EyeRenderDesc eyeDesc = OVRManager.display.GetEyeRenderDesc(UnityEngine.XR.XRNode.LeftEye);
#else
		OVRDisplay.EyeRenderDesc eyeDesc = OVRManager.display.GetEyeRenderDesc(UnityEngine.VR.VRNode.LeftEye);
#endif
        strFOV = System.String.Format("FOV (deg): {0:F3}", eyeDesc.fov.y);   
    }

    /// <summary>
    /// Updates resolution of eye texture
    /// </summary>
    void UpdateResolutionEyeTexture()
    {
#if UNITY_2017_2_OR_NEWER
		OVRDisplay.EyeRenderDesc leftEyeDesc = OVRManager.display.GetEyeRenderDesc(UnityEngine.XR.XRNode.LeftEye);
		OVRDisplay.EyeRenderDesc rightEyeDesc = OVRManager.display.GetEyeRenderDesc(UnityEngine.XR.XRNode.RightEye);

		float scale = UnityEngine.XR.XRSettings.renderViewportScale;
#else
		OVRDisplay.EyeRenderDesc leftEyeDesc = OVRManager.display.GetEyeRenderDesc(UnityEngine.VR.VRNode.LeftEye);
		OVRDisplay.EyeRenderDesc rightEyeDesc = OVRManager.display.GetEyeRenderDesc(UnityEngine.VR.VRNode.RightEye);

		float scale = UnityEngine.VR.VRSettings.renderViewportScale;
#endif
        float w = (int)(scale * (float)(leftEyeDesc.resolution.x + rightEyeDesc.resolution.x));
        float h = (int)(scale * (float)Mathf.Max(leftEyeDesc.resolution.y, rightEyeDesc.resolution.y));

        strResolutionEyeTexture = System.String.Format("Resolution : {0} x {1}", w, h);
    }

    /// <summary>
    /// Updates latency values
    /// </summary>
    void UpdateLatencyValues()
    {
#if !UNITY_ANDROID || UNITY_EDITOR
            OVRDisplay.LatencyData latency = OVRManager.display.latency;
            if (latency.render < 0.000001f && latency.timeWarp < 0.000001f && latency.postPresent < 0.000001f)
                strLatencies = System.String.Format("Latency values are not available.");
            else
                strLatencies = System.String.Format("Render: {0:F3} TimeWarp: {1:F3} Post-Present: {2:F3}\nRender Error: {3:F3} TimeWarp Error: {4:F3}",
                    latency.render,
                    latency.timeWarp,
                    latency.postPresent,
                    latency.renderError,
                    latency.timeWarpError);      
#endif
    }

    /// <summary>
    /// Updates the FPS.
    /// </summary>
    void UpdateFPS()
    {
        timeLeft -= Time.unscaledDeltaTime;
        accum += Time.unscaledDeltaTime;
        ++frames;

        // Interval ended - update GUI text and start new interval
        if (timeLeft <= 0.0)
        {
            // display two fractional digits (f2 format)
            float fps = frames / accum;

            strFPS = System.String.Format("FPS: {0:F2}", fps);

            timeLeft += updateInterval;
            accum = 0.0f;
            frames = 0;
        }
    }
    #endregion
}