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.Nodes.Meshes;
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.Meshs
{
    [CategoryOrder("Mesh", 0)]
    public abstract class DxMeshNodeBase : DxNodeBase
    {
        protected MeshValue? _output;
        protected bool _resourcesCreated;

        protected DxMeshNodeBase()
        {
            var meshGroup = new EndpointGroup("Mesh");
            Outputs.Add(Output = new CodeGenOutputViewModel<MeshValue?>(EPortType.Mesh)
            {
                Name = "Output",
                Group = meshGroup
            });

            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 MeshValue(_output!));

            var dxMeshPreviewViewModel = new DxMeshPreviewViewModel(this, Output.Value);
            Preview = dxMeshPreviewViewModel;
        }

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

        protected bool EnsureMesh(Device device, [NotNull] ref MeshValue? meshValue)
        {
            meshValue = null!;
            //if (false) // TODO: changed
            //{
            //    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 meshModel = (DxMeshModelBase)model;
        }

        public override void LoadModel(NodeModelBase model)
        {
            base.LoadModel(model);
            var meshModel = (DxMeshModelBase)model;
        }

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