using System;
using System.Text;
using Unity.Collections.LowLevel.Unsafe;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.XR.ARFoundation;
using UnityEngine.XR.ARSubsystems;

namespace UnityEngine.XR.ARFoundation.Samples
{
    /// <summary>
    /// This component tests getting the latest camera image
    /// and converting it to RGBA format. If successful,
    /// it displays the image on the screen as a RawImage
    /// and also displays information about the image.
    ///
    /// This is useful for computer vision applications where
    /// you need to access the raw pixels from camera image
    /// on the CPU.
    ///
    /// This is different from the ARCameraBackground component, which
    /// efficiently displays the camera image on the screen. If you
    /// just want to blit the camera texture to the screen, use
    /// the ARCameraBackground, or use Graphics.Blit to create
    /// a GPU-friendly RenderTexture.
    ///
    /// In this example, we get the camera image data on the CPU,
    /// convert it to an RGBA format, then display it on the screen
    /// as a RawImage texture to demonstrate it is working.
    /// This is done as an example; do not use this technique simply
    /// to render the camera image on screen.
    /// </summary>
    public class TestDepthImage : MonoBehaviour
    {
        [SerializeField]
        [Tooltip("The AROcclusionManager which will produce frame events.")]
        AROcclusionManager m_OcclusionManager;

        /// <summary>
        /// Get or set the <c>AROcclusionManager</c>.
        /// </summary>
        public AROcclusionManager occlusionManager
        {
            get { return m_OcclusionManager; }
            set { m_OcclusionManager = value; }
        }

        [SerializeField]
        RawImage m_RawImage;

        /// <summary>
        /// The UI RawImage used to display the image on screen.
        /// </summary>
        public RawImage rawImage
        {
            get { return m_RawImage; }
            set { m_RawImage = value; }
        }

        [SerializeField]
        Text m_ImageInfo;

        /// <summary>
        /// The UI Text used to display information about the image on screen.
        /// </summary>
        public Text imageInfo
        {
            get { return m_ImageInfo; }
            set { m_ImageInfo = value; }
        }

        void LogTextureInfo(StringBuilder stringBuilder, string textureName, Texture2D texture)
        {
            stringBuilder.AppendFormat("texture : {0}\n", textureName);
            if (texture == null)
            {
                stringBuilder.AppendFormat("   <null>\n");
            }
            else
            {
                stringBuilder.AppendFormat("   format : {0}\n", texture.format.ToString());
                stringBuilder.AppendFormat("   width  : {0}\n", texture.width);
                stringBuilder.AppendFormat("   height : {0}\n", texture.height);
                stringBuilder.AppendFormat("   mipmap : {0}\n", texture.mipmapCount);
            }
        }

        void Update()
        {
            Debug.Assert(m_OcclusionManager != null, "no occlusion manager");
            if ((m_OcclusionManager.descriptor?.supportsHumanSegmentationStencilImage == false)
                && (m_OcclusionManager.descriptor?.supportsHumanSegmentationDepthImage == false)
                && (m_OcclusionManager.descriptor?.supportsEnvironmentDepthImage == false))
            {
                if (m_ImageInfo != null)
                {
                    m_ImageInfo.text = "Depth functionality is not supported on this device.";
                }
                return;
            }

            StringBuilder sb = new StringBuilder();
            Texture2D humanStencil = m_OcclusionManager.humanStencilTexture;
            Texture2D humanDepth = m_OcclusionManager.humanDepthTexture;
            Texture2D envDepth = m_OcclusionManager.environmentDepthTexture;
            LogTextureInfo(sb, "stencil", humanStencil);
            LogTextureInfo(sb, "depth", humanDepth);
            LogTextureInfo(sb, "env", envDepth);

            if (m_ImageInfo != null)
            {
                m_ImageInfo.text = sb.ToString();
            }
            else
            {
                Debug.Log(sb.ToString());
            }

            // To use the stencil, be sure the HumanSegmentationStencilMode property on the AROcclusionManager is set to a
            // non-disabled value.
            m_RawImage.texture = envDepth;

            // To use the depth, be sure the HumanSegmentationDepthMode property on the AROcclusionManager is set to a
            /// non-disabled value.
            // m_RawImage.texture = eventArgs.humanDepth;
        }
    }
}