namespace RealTimeGraphEx.DX2D
{
    using SharpDX;
    using SharpDX.Direct2D1;
    using SharpDX.Direct3D10;
    using SharpDX.DXGI;
    using System;
    using System.ComponentModel;
    using System.Diagnostics;
    using System.Threading;
    using System.Windows;
    using Device = SharpDX.Direct3D10.Device1;
    using FeatureLevel = SharpDX.Direct3D10.FeatureLevel;

    public abstract class Direct2DControl : System.Windows.Controls.Image
    {
        private Device Device;
        private Texture2D RenderTarget;
        private DX10ImageSource D3DSurface;
        private readonly Stopwatch RenderTimer;
        private RenderTarget m_d2dRenderTarget;
        protected SharpDX.Direct2D1.Factory m_d2dFactory;
        private bool enableRendering;
        //private Stopwatch renderWatch;

        //public int FrameRate { get; set; }

        public Direct2DControl()
        {
            //renderWatch = new Stopwatch();
            //FrameRate = 60;
            this.RenderTimer = new Stopwatch();
            this.Loaded += this.Window_Loaded;
            this.Unloaded += this.Window_Closing;
            this.Stretch = System.Windows.Media.Stretch.Fill;
        }

        public void EnableRendering()
        {
            enableRendering = true;
        }

        public void DisableRendering()
        {
            enableRendering = false;
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            if (Direct2DControl.IsInDesignMode)
            {
                return;
            }

            this.StartD3D();
            this.StartRendering();
        }

        private void Window_Closing(object sender, RoutedEventArgs e)
        {
            if (Direct2DControl.IsInDesignMode)
            {
                return;
            }

            this.StopRendering();
            this.EndD3D();
        }

        private void StartD3D()
        {
            this.Device = new Device(DriverType.Hardware, DeviceCreationFlags.BgraSupport, FeatureLevel.Level_10_0);

            this.D3DSurface = new DX10ImageSource();
            this.D3DSurface.IsFrontBufferAvailableChanged += OnIsFrontBufferAvailableChanged;

            this.CreateAndBindTargets();

            this.Source = this.D3DSurface;
        }

        private void EndD3D()
        {
            this.D3DSurface.IsFrontBufferAvailableChanged -= OnIsFrontBufferAvailableChanged;
            this.Source = null;

            Disposer.SafeDispose(ref this.m_d2dRenderTarget);
            Disposer.SafeDispose(ref this.m_d2dFactory);
            Disposer.SafeDispose(ref this.D3DSurface);
            Disposer.SafeDispose(ref this.RenderTarget);
            Disposer.SafeDispose(ref this.Device);
        }

        private void CreateAndBindTargets()
        {
            if (this.D3DSurface == null) return;

            this.D3DSurface.SetRenderTargetDX10(null);

            Disposer.SafeDispose(ref this.m_d2dRenderTarget);
            Disposer.SafeDispose(ref this.m_d2dFactory);
            Disposer.SafeDispose(ref this.RenderTarget);

            var width = Math.Max((int)this.ActualWidth, 100);
            var height = Math.Max((int)this.ActualHeight, 100);

            var colordesc = new Texture2DDescription
            {
                BindFlags = BindFlags.RenderTarget | BindFlags.ShaderResource,
                Format = Format.B8G8R8A8_UNorm,
                Width = width,
                Height = height,
                MipLevels = 1,
                SampleDescription = new SampleDescription(1, 0),
                Usage = ResourceUsage.Default,
                OptionFlags = ResourceOptionFlags.Shared,
                CpuAccessFlags = CpuAccessFlags.None,
                ArraySize = 1
            };

            this.RenderTarget = new Texture2D(this.Device, colordesc);

            var surface = this.RenderTarget.QueryInterface<Surface>();

            m_d2dFactory = new SharpDX.Direct2D1.Factory();
            var rtp = new RenderTargetProperties(new PixelFormat(Format.Unknown, AlphaMode.Premultiplied));
            m_d2dRenderTarget = new RenderTarget(m_d2dFactory, surface, rtp);

            this.D3DSurface.SetRenderTargetDX10(this.RenderTarget);
        }

        private void StartRendering()
        {
            if (this.RenderTimer.IsRunning)
            {
                return;
            }

            System.Windows.Media.CompositionTarget.Rendering += OnRendering;
            this.RenderTimer.Start();
            //renderWatch.Start();
        }

        private void StopRendering()
        {
            if (!this.RenderTimer.IsRunning)
            {
                return;
            }

            System.Windows.Media.CompositionTarget.Rendering -= OnRendering;
            this.RenderTimer.Stop();
            RenderTimer.Stop();
        }

        private void OnRendering(object sender, EventArgs e)
        {
            if (!this.RenderTimer.IsRunning)
            {
                return;
            }

            //if (renderWatch.ElapsedMilliseconds >= (1000 / FrameRate))
            //{
            //renderWatch.Restart();
            if (enableRendering)
            {
                this.PrepareAndCallRender();
                this.D3DSurface.InvalidateD3DImage();
            }
            //}
        }

        protected override void OnRenderSizeChanged(SizeChangedInfo sizeInfo)
        {
            this.CreateAndBindTargets();
            base.OnRenderSizeChanged(sizeInfo);
        }

        private void PrepareAndCallRender()
        {
            var device = this.Device;
            if (device == null)
            {
                return;
            }

            var renderTarget = this.RenderTarget;
            if (renderTarget == null)
            {
                return;
            }

            var targetWidth = renderTarget.Description.Width;
            var targetHeight = renderTarget.Description.Height;

            device.Rasterizer.SetViewports(new Viewport(0, 0, targetWidth, targetHeight, 0.0f, 1.0f));


            // Does the actual rendering
            m_d2dRenderTarget.BeginDraw();
            this.Render(m_d2dRenderTarget);
            m_d2dRenderTarget.EndDraw();
            //this.ShowFramesPerSecondsOnDebug();

            device.Flush();
        }

        /// <summary>
        /// Does the actual rendering. 
        /// BeginDraw and EndDraw are already called by the caller. 
        /// </summary>
        public abstract void Render(RenderTarget target);

        /// <summary>
        /// Shows the number of frames per seconds on the debug line
        /// </summary>
        private void ShowFramesPerSecondsOnDebug()
        {
            // Spits out the Frames per second
            f++;
            if ((DateTime.Now - last).TotalSeconds > 1)
            {
                System.Diagnostics.Debug.WriteLine(f);
                f = 0;
                last = DateTime.Now;
            }
        }

        private DateTime last;
        private int f;

        private void OnIsFrontBufferAvailableChanged(object sender, DependencyPropertyChangedEventArgs e)
        {
            // this fires when the screensaver kicks in, the machine goes into sleep or hibernate
            // and any other catastrophic losses of the d3d device from WPF's point of view
            if (this.D3DSurface.IsFrontBufferAvailable)
            {
                this.StartRendering();
            }
            else
            {
                this.StopRendering();
            }
        }

        /// <summary>
        /// Gets f value indicating whether the control is in design mode
        /// (running in Blend or Visual Studio).
        /// </summary>
        public static bool IsInDesignMode
        {
            get
            {
                var prop = DesignerProperties.IsInDesignModeProperty;
                var isDesignMode = (bool)DependencyPropertyDescriptor.FromProperty(prop, typeof(FrameworkElement)).Metadata.DefaultValue;
                return isDesignMode;
            }
        }
    }
}