using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using Unity.Collections;
using Unity.Profiling;
using Unity.Simulation;
using UnityEditor;
using UnityEngine;
using UnityEngine.Experimental.Rendering;
using UnityEngine.Profiling;

namespace UnityEngine.Perception.GroundTruth
{
    /// <summary>
    ///  Produces instance segmentation for each frame.
    /// </summary>
    [Serializable]
    public sealed class InstanceSegmentationLabeler : CameraLabeler, IOverlayPanelProvider
    {
        ///<inheritdoc/>
        public override string description
        {
            get => "Produces an instance segmentation image for each frame. The image will render the pixels of each labeled object in a distinct color.";
            protected set { }
        }

        /// <inheritdoc/>
        protected override bool supportsVisualization => true;

        static readonly string k_Directory = "InstanceSegmentation" + Guid.NewGuid().ToString();
        const string k_FilePrefix = "Instance_";

        /// <summary>
        /// The GUID to associate with annotations produced by this labeler.
        /// </summary>
        [Tooltip("The id to associate with instance segmentation annotations in the dataset.")]
        public string annotationId = "1ccebeb4-5886-41ff-8fe0-f911fa8cbcdf";

        /// <summary>
        /// The <see cref="idLabelConfig"/> which associates objects with labels.
        /// </summary>
        public IdLabelConfig idLabelConfig;

        AnnotationDefinition m_AnnotationDefinition;

        static ProfilerMarker s_OnObjectInfoReceivedCallback = new ProfilerMarker("OnInstanceSegmentationObjectInformationReceived");
        static ProfilerMarker s_OnImageReceivedCallback = new ProfilerMarker("OnInstanceSegmentationImagesReceived");

        Dictionary<int, AsyncAnnotation> m_AsyncAnnotations;
        Texture m_CurrentTexture;

        /// <inheritdoc cref="IOverlayPanelProvider"/>
        // ReSharper disable once ConvertToAutoPropertyWithPrivateSetter
        public Texture overlayImage => m_CurrentTexture;

        /// <inheritdoc cref="IOverlayPanelProvider"/>
        public string label => "InstanceSegmentation";

        [SuppressMessage("ReSharper", "InconsistentNaming")]
        [SuppressMessage("ReSharper", "NotAccessedField.Local")]
        struct InstanceColorValue
        {
            public uint instance_id;
            public Color32 color;
        }

        string m_InstancePath;
        List<InstanceColorValue> m_InstanceColorValues;

        struct AsyncWrite
        {
            public NativeArray<Color32> data;
            public int width;
            public int height;
            public string path;
        }

        /// <summary>
        /// Creates a new InstanceSegmentationLabeler. Be sure to assign <see cref="idLabelConfig"/> before adding to a <see cref="PerceptionCamera"/>.
        /// </summary>
        public InstanceSegmentationLabeler() { }

        /// <summary>
        /// Creates a new InstanceSegmentationLabeler with the given <see cref="IdLabelConfig"/>.
        /// </summary>
        /// <param name="labelConfig">The label config for resolving the label for each object.</param>
        public InstanceSegmentationLabeler(IdLabelConfig labelConfig)
        {
            this.idLabelConfig = labelConfig;
        }

        void OnRenderedObjectInfosCalculated(int frame, NativeArray<RenderedObjectInfo> renderedObjectInfos)
        {
            if (!m_AsyncAnnotations.TryGetValue(frame, out var annotation))
                return;

            m_AsyncAnnotations.Remove(frame);

            using (s_OnObjectInfoReceivedCallback.Auto())
            {
                m_InstanceColorValues.Clear();

                foreach (var objectInfo in renderedObjectInfos)
                {
                    if (!idLabelConfig.TryGetLabelEntryFromInstanceId(objectInfo.instanceId, out var labelEntry))
                        continue;

                    m_InstanceColorValues.Add(new InstanceColorValue
                    {
                        instance_id = objectInfo.instanceId,
                        color = objectInfo.instanceColor
                    });
                }

                annotation.ReportFileAndValues(m_InstancePath, m_InstanceColorValues);
            }
        }

        void OnImageCaptured(int frame, NativeArray<Color32> data, RenderTexture renderTexture)
        {
            using (s_OnImageReceivedCallback.Auto())
            {
                m_CurrentTexture = renderTexture;

                m_InstancePath = $"{k_Directory}/{k_FilePrefix}{frame}.png";
                var localPath = $"{Manager.Instance.GetDirectoryFor(k_Directory)}/{k_FilePrefix}{frame}.png";

                var colors = new NativeArray<Color32>(data, Allocator.TempJob);

                var asyncRequest = Manager.Instance.CreateRequest<AsyncRequest<AsyncWrite>>();

                asyncRequest.data = new AsyncWrite
                {
                    data = colors,
                    width = renderTexture.width,
                    height = renderTexture.height,
                    path = localPath
                };

                asyncRequest.Enqueue(r =>
                {
                    Profiler.BeginSample("InstanceSegmentationEncode");
                    var pngBytes = ImageConversion.EncodeArrayToPNG(r.data.data.ToArray(), GraphicsFormat.R8G8B8A8_UNorm, (uint)r.data.width, (uint)r.data.height);
                    Profiler.EndSample();
                    Profiler.BeginSample("InstanceSegmentationWritePng");
                    File.WriteAllBytes(r.data.path, pngBytes);
                    Manager.Instance.ConsumerFileProduced(r.data.path);
                    Profiler.EndSample();
                    r.data.data.Dispose();
                    return AsyncRequest.Result.Completed;
                });
                asyncRequest.Execute();
            }
        }

        /// <inheritdoc/>
        protected override void OnBeginRendering()
        {
            m_AsyncAnnotations[Time.frameCount] = perceptionCamera.SensorHandle.ReportAnnotationAsync(m_AnnotationDefinition);
        }

        /// <inheritdoc/>
        protected override void Setup()
        {
            if (idLabelConfig == null)
                throw new InvalidOperationException("InstanceSegmentationLabeler's idLabelConfig field must be assigned");

            m_InstanceColorValues = new List<InstanceColorValue>();

            perceptionCamera.InstanceSegmentationImageReadback += OnImageCaptured;
            perceptionCamera.RenderedObjectInfosCalculated += OnRenderedObjectInfosCalculated;

            m_AsyncAnnotations = new Dictionary<int, AsyncAnnotation>();

            m_AnnotationDefinition = DatasetCapture.RegisterAnnotationDefinition(
                "instance segmentation",
                idLabelConfig.GetAnnotationSpecification(),
                "pixel-wise instance segmentation label",
                "PNG",
                Guid.Parse(annotationId));

            visualizationEnabled = supportsVisualization;
        }
    }
}