using System;
using System.Diagnostics.CodeAnalysis;
using System.Reactive.Linq;
using DynamicData;
using Intromat.Graphics;
using Intromat.Model.Compiler;
using Intromat.Nodes.Code;
using Intromat.PersistentModel;
using Intromat.ViewModels;
using Intromat.ViewModels.Editors;
using Intromat.ViewModels.Previews;
using NodeNetwork.Toolkit.ValueNode;
using NodeNetwork.ViewModels;
using ReactiveUI;
using SharpDX.Direct3D11;
using SharpDX.DXGI;
using Splat;
using Xceed.Wpf.Toolkit.PropertyGrid.Attributes;
using Device = SharpDX.Direct3D11.Device;

namespace Intromat.Nodes.Textures
{
    [CategoryOrder("Texture", 0)]
    public abstract class DxTextureNodeBase : DxNodeBase
    {
        protected TextureValue? _output;
        protected Texture2DDescription _texDesc;
        protected bool _resourcesCreated;

        protected DxTextureNodeBase()
        {
            var textureGroup = new EndpointGroup("Texture");
            var parentObservable = this.WhenAnyObservable(vm => vm.ParentChanged).Select(parent => (CodeGenNetworkViewModel?)parent);
            Inputs.Add(Width = new CodeGenInputViewModel<ITypedExpression<int>>(EPortType.None)
            {
                Name = "Width",
                Group = textureGroup,
                Editor = WidthEditor = new()
                {
                    ParentValueProvider = parentObservable.Select(parent => parent?.DefaultWidth ?? -1),
                    MinValue = -16,
                    MaxValue = 16,
                    CustomValue = 0,
                    RelativeSource = ERelativeSource.Parent
                }
            });
            Inputs.Add(Height = new CodeGenInputViewModel<ITypedExpression<int>>(EPortType.None)
            {
                Name = "Height",
                Group = textureGroup,
                Editor = HeightEditor = new()
                {
                    ParentValueProvider = parentObservable.Select(parent => parent?.DefaultHeight ?? -1),
                    MinValue = -16,
                    MaxValue = 16,
                    CustomValue = 0,
                    RelativeSource = ERelativeSource.Parent
                }
            });
            Outputs.Add(Output = new CodeGenOutputViewModel<TextureValue?>(EPortType.Texture)
            {
                Name = "Output",
                Group = textureGroup
            });

            var dxHost = Locator.Current.GetService<DxHost>()!;
            Output.Value = this
                .WhenAnyObservable(vm => vm.ParentChanged, vm => vm.AnyInputChanged, (parent, _) => parent)
                .Where(parent => parent != null)
                .Throttle(TimeSpan.FromMilliseconds(1))
                .ObserveOn(dxHost.RenderDispatcher)
                .Do(_ => { UpdateFrame(dxHost.Device, dxHost.Device.ImmediateContext); })
                .Select(_ => new TextureValue(_output!));

            var dxTexturePreviewViewModel = new DxTexturePreviewViewModel(this, Output.Value);
            Preview = dxTexturePreviewViewModel;

            _texDesc = new Texture2DDescription
            {
                ArraySize = 1,
                Format = Format.R16G16B16A16_Float,
                BindFlags = BindFlags.ShaderResource | BindFlags.UnorderedAccess,
                Usage = ResourceUsage.Default,
                SampleDescription = new(1, 0)
            };
        }

        [MemberNotNull(nameof(_output))]
        protected bool EnsureBuffers(Device device)
        {
            return EnsureTexture(device, ref _output);
        }

        protected bool EnsureTexture(Device device, [NotNull] ref TextureValue? textureValue)
        {
            var width = ((IntLiteralValue)Width.Value).EvaluateDimension();
            var height = ((IntLiteralValue)Height.Value).EvaluateDimension();
            if (_texDesc.Width != width || _texDesc.Height != height || textureValue == null)
            {
                textureValue?.ShaderResourceView?.Resource?.Dispose();
                textureValue?.ShaderResourceView?.Dispose();
                textureValue?.UnorderedAccessView?.Dispose();

                _texDesc.Width = width;
                _texDesc.Height = height;
                var texture = new Texture2D(device, _texDesc);

                textureValue ??= new TextureValue();
                textureValue.Width = width;
                textureValue.Height = height;
                textureValue.ShaderResourceView = new ShaderResourceView(device, texture);
                textureValue.UnorderedAccessView = new UnorderedAccessView(device, texture);
                return true;
            }

            return false;
        }

        protected virtual void UpdateFrame(Device device, DeviceContext deviceContext)
        {
            if (!_resourcesCreated)
            {
                _resourcesCreated = true;
                CreateDeviceResources(device);
            }
            EnsureBuffers(device);
        }

        protected virtual void CreateDeviceResources(Device device)
        {
        }

        public override void SaveModel(NodeModelBase model)
        {
            base.SaveModel(model);
            var textureModel = (DxTextureModelBase)model;
            textureModel.Width = WidthEditor.CreateModel();
            textureModel.Height = HeightEditor.CreateModel();
        }

        public override void LoadModel(NodeModelBase model)
        {
            base.LoadModel(model);
            var textureModel = (DxTextureModelBase)model;
            WidthEditor.LoadModel(textureModel.Width);
            HeightEditor.LoadModel(textureModel.Height);
        }

        public DimensionEditorViewModel WidthEditor { get; }
        public ValueNodeInputViewModel<ITypedExpression<int>> Width { get; }

        public DimensionEditorViewModel HeightEditor { get; }
        public ValueNodeInputViewModel<ITypedExpression<int>> Height { get; }

        public ValueNodeOutputViewModel<TextureValue?> Output { get; }
    }
}