using System;
using System.Collections.Generic;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.Threading.Tasks;

namespace BuzzGUI.WaveformControl
{
    public class SegmentVisual : DrawingVisual
    {
		public class Resources
		{
			public Brush fill;
			public Pen pen;

			public Resources(WaveformElement e, int h)
			{
				fill = e.FindResource("FillBrush") as Brush;
				if (fill is LinearGradientBrush)
				{
					LinearGradientBrush lgb = fill.Clone() as LinearGradientBrush;
					lgb.EndPoint = new Point(0, h);
					fill = lgb as Brush;
				}
				fill.Freeze();


                pen = new Pen(e.FindResource("WaveformOutlineBrush") as Brush, 0.5);
				pen.Freeze();
			}


		}

        public bool Allocated = false;
        public int SampleIndex;
        RenderTargetBitmap rtb;

        public SegmentVisual()
        {
			/*
			this.CacheMode = new BitmapCache()
			{
				RenderAtScale = 1.0,
				SnapsToDevicePixels = true
			};
			 */
        }

		Task task;
		bool bg = false;

        public void Render(WaveformElement wfc, MinMaxCache mmc, int mmcindex, int sampleWidth, int height, Resources r)
        {
            if (height <= 0)
                return;


			if (bg)
			{
				if (task != null)
					task.Wait();

				task = Task.Factory.StartNew(() =>
				{
					MinMaxCache.MinMax[] points = null;

					lock (this)
					{
						points = mmc.GetSegmentPlusOne(mmcindex);
						CreatePiece(wfc, points, sampleWidth, height, r);
						rtb.Freeze();
					}

					Dispatcher.BeginInvoke(new Action(() =>
					{
						lock (this)
						{
							var dc = RenderOpen();
							dc.DrawImage(rtb, new Rect(0, 0, points.Length * sampleWidth, height));
							dc.Close();
						}
					}), System.Windows.Threading.DispatcherPriority.ApplicationIdle);

				});
			}
			else
			{
				MinMaxCache.MinMax[] points = null;
				points = mmc.GetSegmentPlusOne(mmcindex);
				CreatePiece(wfc, points, sampleWidth, height, r);
				var dc = RenderOpen();
				dc.DrawImage(rtb, new Rect(0, 0, points.Length * sampleWidth, height));
				dc.Close();
			}

        }
	
        void CreatePiece(WaveformElement wfc, MinMaxCache.MinMax[] points, int pw, int h, Resources r)
        {
            double my = h / 2;

			DrawingVisual dv = new DrawingVisual();
			DrawingContext dc = dv.RenderOpen();

            PathFigure pf = new PathFigure();
            PathFigure spf = new PathFigure();
            PathFigure spf2 = new PathFigure();

            pf.StartPoint = new Point(0, my);
            for (int i = 0; i < points.Length; i++)
            {
                double v = my - points[i].MaxNormalized * my;

                pf.Segments.Add(new LineSegment(new Point(pw * i, v), true));

                if (i == 0)
                    spf.StartPoint = new Point(0, v);
                else
                    spf.Segments.Add(new LineSegment(new Point(pw * i, v), true));
            }

            pf.Segments.Add(new LineSegment(new Point(pw * (points.Length - 1), my), true));

            for (int i = points.Length - 1; i >= 0; i--)
            {
                double v = my - points[i].MinNormalized * my;

                pf.Segments.Add(new LineSegment(new Point(pw * i, v), true));

                if (i == points.Length - 1)
                    spf2.StartPoint = new Point(pw * i, v);
                else
                    spf2.Segments.Add(new LineSegment(new Point(pw * i, v), true));                 
            }

            pf.Segments.Add(new LineSegment(new Point(0, my), true));

            PathGeometry pg = new PathGeometry();
            pg.Figures.Add(pf);

            dc.DrawGeometry(r.fill, null, pg);

            PathGeometry spg = new PathGeometry();
            spg.Figures.Add(spf);
            dc.DrawGeometry(null, r.pen, spg);

            PathGeometry spg2 = new PathGeometry();
            spg2.Figures.Add(spf2);
            dc.DrawGeometry(null, r.pen, spg2);

            dc.Close();

			if (rtb == null || bg)
				rtb = new RenderTargetBitmap(pw * points.Length, h, 96, 96, PixelFormats.Pbgra32);
			else
				rtb.Clear();

			rtb.Render(dv);

			if (bg) rtb.Freeze();
        }
		
    }
}