using LibAudioVisualizer;
using NAudio.CoreAudioApi;
using NAudio.Wave;
using System.Drawing.Drawing2D;
using System.Numerics;

namespace AudioVisualizer
{
    public partial class MainWindow : Form
    {
        WasapiCapture capture;             // 音频捕获
        Visualizer visualizer;             // 可视化
        double[]? spectrumData;            // 频谱数据

        Color[] allColors;                 // 渐变颜色

        public MainWindow()
        {
            capture = new WasapiLoopbackCapture();          // 捕获电脑发出的声音
            visualizer = new Visualizer(256);               // 新建一个可视化器, 并使用 256 个采样进行傅里叶变换

            allColors = GetAllHsvColors();                  // 获取所有的渐变颜色 (HSV 颜色)

            capture.WaveFormat = WaveFormat.CreateIeeeFloatWaveFormat(8192, 1);      // 指定捕获的格式, 单声道, 32位深度, IeeeFloat 编码, 8192采样率
            capture.DataAvailable += Capture_DataAvailable;                          // 订阅事件

            InitializeComponent();
        }

        /// <summary>
        /// 获取 HSV 中所有的基础颜色 (饱和度和明度均为最大值)
        /// </summary>
        /// <returns>所有的 HSV 基础颜色(共 256 * 6 个, 并且随着索引增加, 颜色也会渐变)</returns>
        private Color[] GetAllHsvColors()
        {
            Color[] result = new Color[256 * 6];

            for (int i = 0; i < 256; i++)
            {
                result[i] = Color.FromArgb(255, i, 0);
            }

            for (int i = 0; i < 256; i++)
            {
                result[256 + i] = Color.FromArgb(255 - i, 255, 0);
            }

            for (int i = 0; i < 256; i++)
            {
                result[512 + i] = Color.FromArgb(0, 255, i);
            }

            for (int i = 0; i < 256; i++)
            {
                result[768 + i] = Color.FromArgb(0, 255 - i, 255);
            }

            for (int i = 0; i < 256; i++)
            {
                result[1024 + i] = Color.FromArgb(i, 0, 255);
            }

            for (int i = 0; i < 256; i++)
            {
                result[1280 + i] = Color.FromArgb(255, 0, 255 - i);
            }

            return result;
        }

        /// <summary>
        /// 当捕获有数据的时候, 就怼到可视化器里面
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Capture_DataAvailable(object? sender, WaveInEventArgs e)
        {
            int length = e.BytesRecorded / 4;           // 采样的数量 (每一个采样是 4 字节)
            double[] result = new double[length];       // 声明结果

            for (int i = 0; i < length; i++)
                result[i] = BitConverter.ToSingle(e.Buffer, i * 4);      // 取出采样值

            visualizer.PushSampleData(result);          // 将新的采样存储到 可视化器 中
        }

        /// <summary>
        /// 用来刷新频谱数据以及实现频谱数据缓动
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void DataTimer_Tick(object? sender, EventArgs e)
        {
            double[] newSpectrumData = visualizer.GetSpectrumData();         // 从可视化器中获取频谱数据
            newSpectrumData = Visualizer.GetBlurry(newSpectrumData, 2);                // 平滑频谱数据

            spectrumData = newSpectrumData;
        }

        /// <summary>
        /// 绘制一个渐变的 波浪
        /// </summary>
        /// <param name="g">绘图目标</param>
        /// <param name="down">下方颜色</param>
        /// <param name="up">上方颜色</param>
        /// <param name="spectrumData">频谱数据</param>
        /// <param name="pointCount">波浪中, 点的数量</param>
        /// <param name="drawingWidth">波浪的宽度</param>
        /// <param name="xOffset">波浪的起始X坐标</param>
        /// <param name="yOffset">波浪的其实Y坐标</param>
        /// <param name="scale">频谱的缩放(使用负值可以翻转波浪)</param>
        private void DrawGradient(Graphics g, Color down, Color up, double[] spectrumData, int pointCount, int drawingWidth, float xOffset, float yOffset, double scale)
        {
            GraphicsPath path = new GraphicsPath();

            PointF[] points = new PointF[pointCount + 2];
            for (int i = 0; i < pointCount; i++)
            {
                double x = i * drawingWidth / pointCount + xOffset;
                double y = spectrumData[i * spectrumData.Length / pointCount] * scale + yOffset;
                points[i + 1] = new PointF((float)x, (float)y);
            }

            points[0] = new PointF(xOffset, yOffset);
            points[points.Length - 1] = new PointF(xOffset + drawingWidth, yOffset);

            path.AddCurve(points);

            float upP = (float)points.Min(v => v.Y);

            if (Math.Abs(upP - yOffset) < 1)
                return;

            using Brush brush = new LinearGradientBrush(new PointF(0, yOffset), new PointF(0, upP), down, up);
            g.FillPath(brush, path);
        }

        /// <summary>
        /// 绘制渐变的条形
        /// </summary>
        /// <param name="g">绘图目标</param>
        /// <param name="down">下方颜色</param>
        /// <param name="up">上方颜色</param>
        /// <param name="spectrumData">频谱数据</param>
        /// <param name="stripCount">条形的数量</param>
        /// <param name="drawingWidth">绘图的宽度</param>
        /// <param name="xOffset">绘图的起始 X 坐标</param>
        /// <param name="yOffset">绘图的起始 Y 坐标</param>
        /// <param name="spacing">条形与条形之间的间隔(像素)</param>
        /// <param name="scale"></param>
        private void DrawGradientStrips(Graphics g, Color down, Color up, double[] spectrumData, int stripCount, int drawingWidth, float xOffset, float yOffset, float spacing, double scale)
        {
            float stripWidth = (drawingWidth - spacing * stripCount) / stripCount;
            PointF[] points = new PointF[stripCount];

            for (int i = 0; i < stripCount; i++)
            {
                double x = stripWidth * i + spacing * i + xOffset;
                double y = spectrumData[i * spectrumData.Length / stripCount] * scale;   // height
                points[i] = new PointF((float)x, (float)y);
            }

            float upP = (float)points.Min(v => v.Y < 0 ? yOffset + v.Y : yOffset);
            float downP = (float)points.Max(v => v.Y < 0 ? yOffset : yOffset + v.Y);

            if (downP < yOffset)
                downP = yOffset;

            if (Math.Abs(upP - downP) < 1)
                return;

            using Brush brush = new LinearGradientBrush(new PointF(0, downP), new PointF(0, upP), down, up);

            for (int i = 0; i < stripCount; i++)
            {
                PointF p = points[i];
                float y = yOffset;
                float height = p.Y;

                if (height < 0)
                {
                    y += height;
                    height = -height;
                }

                g.FillRectangle(brush, new RectangleF(p.X, y, stripWidth, height));
            }
        }

        /// <summary>
        /// 画曲线
        /// </summary>
        /// <param name="g"></param>
        /// <param name="pen"></param>
        /// <param name="spectrumData"></param>
        /// <param name="pointCount"></param>
        /// <param name="drawingWidth"></param>
        /// <param name="xOffset"></param>
        /// <param name="yOffset"></param>
        /// <param name="scale"></param>
        private void DrawCurve(Graphics g, Pen pen, double[] spectrumData, int pointCount, int drawingWidth, double xOffset, double yOffset, double scale)
        {
            PointF[] points = new PointF[pointCount];
            for (int i = 0; i < pointCount; i++)
            {
                double x = i * drawingWidth / pointCount + xOffset;
                double y = spectrumData[i * spectrumData.Length / pointCount] * scale + yOffset;
                points[i] = new PointF((float)x, (float)y);
            }

            g.DrawCurve(pen, points);
        }

        /// <summary>
        /// 画简单的圆环线条
        /// </summary>
        /// <param name="g"></param>
        /// <param name="brush"></param>
        /// <param name="spectrumData"></param>
        /// <param name="stripCount"></param>
        /// <param name="xOffset"></param>
        /// <param name="yOffset"></param>
        /// <param name="radius"></param>
        /// <param name="spacing"></param>
        /// <param name="rotation"></param>
        /// <param name="scale"></param>
        private void DrawCircleStrips(Graphics g, Brush brush, double[] spectrumData, int stripCount, double xOffset, double yOffset, double radius, double spacing, double rotation, double scale)
        {
            double rotationAngle = Math.PI / 180 * rotation;
            double blockWidth = MathF.PI * 2 / stripCount;           // angle
            double stripWidth = blockWidth - MathF.PI / 180 * spacing;                // angle
            PointF[] points = new PointF[stripCount];

            for (int i = 0; i < stripCount; i++)
            {
                double x = blockWidth * i + rotationAngle;      // angle
                double y = spectrumData[i * spectrumData.Length / stripCount] * scale;   // height
                points[i] = new PointF((float)x, (float)y);
            }

            for (int i = 0; i < stripCount; i++)
            {
                PointF p = points[i];
                double sinStart = Math.Sin(p.X);
                double sinEnd = Math.Sin(p.X + stripWidth);
                double cosStart = Math.Cos(p.X);
                double cosEnd = Math.Cos(p.X + stripWidth);

                PointF[] polygon = new PointF[]
                {
                    new PointF((float)(cosStart * radius + xOffset), (float)(sinStart * radius + yOffset)),
                    new PointF((float)(cosEnd * radius + xOffset), (float)(sinEnd * radius + yOffset)),
                    new PointF((float)(cosEnd * (radius + p.Y) + xOffset), (float)(sinEnd * (radius + p.Y) + yOffset)),
                    new PointF((float)(cosStart * (radius + p.Y) + xOffset), (float)(sinStart * (radius + p.Y) + yOffset)),
                };

                g.FillPolygon(brush, polygon);
            }
        }

        /// <summary>
        /// 画圆环渐变条
        /// </summary>
        /// <param name="g"></param>
        /// <param name="inner"></param>
        /// <param name="outer"></param>
        /// <param name="spectrumData"></param>
        /// <param name="stripCount"></param>
        /// <param name="xOffset"></param>
        /// <param name="yOffset"></param>
        /// <param name="radius"></param>
        /// <param name="spacing"></param>
        /// <param name="scale"></param>
        private void DrawCircleGradientStrips(Graphics g, Color inner, Color outer, double[] spectrumData, int stripCount, double xOffset, double yOffset, double radius, double spacing, double rotation, double scale)
        {
            double rotationAngle = Math.PI / 180 * rotation;
            double blockWidth = Math.PI * 2 / stripCount;           // angle
            double stripWidth = blockWidth - MathF.PI / 180 * spacing;                // angle
            PointF[] points = new PointF[stripCount];

            for (int i = 0; i < stripCount; i++)
            {
                double x = blockWidth * i + rotationAngle;      // angle
                double y = spectrumData[i * spectrumData.Length / stripCount] * scale;   // height
                points[i] = new PointF((float)x, (float)y);
            }

            double maxHeight = points.Max(v =>  v.Y);
            double outerRadius = radius + maxHeight;

            PointF[] polygon = new PointF[4];
            for (int i = 0; i < stripCount; i++)
            {
                PointF p = points[i];
                double sinStart = Math.Sin(p.X);
                double sinEnd = Math.Sin(p.X + stripWidth);
                double cosStart = Math.Cos(p.X);
                double cosEnd = Math.Cos(p.X + stripWidth);

                PointF
                    p1 = new PointF((float)(cosStart * radius + xOffset),(float)(sinStart * radius + yOffset)),
                    p2 = new PointF((float)(cosEnd * radius + xOffset),(float)(sinEnd * radius + yOffset)),
                    p3 = new PointF((float)(cosEnd * (radius + p.Y) + xOffset), (float)(sinEnd * (radius + p.Y) + yOffset)),
                    p4 = new PointF((float)(cosStart * (radius + p.Y) + xOffset), (float)(sinStart * (radius + p.Y) + yOffset));

                polygon[0] = p1;
                polygon[1] = p2;
                polygon[2] = p3;
                polygon[3] = p4;


                PointF innerP = new PointF((p1.X + p2.X) / 2, (p1.Y + p2.Y) / 2);
                PointF outerP = new PointF((p3.X + p4.X) / 2, (p3.Y + p4.Y) / 2);

                Vector2 offset = new Vector2(outerP.X - innerP.X, outerP.Y - innerP.Y);
                if (MathF.Sqrt(offset.X * offset.X + offset.Y * offset.Y) < 1)                                // 渐变笔刷两点之间距离不能太小
                    continue;

                try
                {
                    using LinearGradientBrush brush = new LinearGradientBrush(innerP, outerP, inner, outer);        // 这里有玄学 bug, 这个 线性笔刷会 OutMemoryException
                    g.FillPolygon(brush, polygon);                                                            // 但是实际上不应该有这个异常...
                }
                catch { }
            }
        }

        /// <summary>
        /// 画简单的线条
        /// </summary>
        /// <param name="g"></param>
        /// <param name="brush"></param>
        /// <param name="spectrumData"></param>
        /// <param name="stripCount"></param>
        /// <param name="drawingWidth"></param>
        /// <param name="xOffset"></param>
        /// <param name="yOffset"></param>
        /// <param name="spacing"></param>
        /// <param name="scale"></param>
        private void DrawStrips(Graphics g, Brush brush, double[] spectrumData, int stripCount, int drawingWidth, float xOffset, float yOffset, float spacing, double scale)
        {
            float stripWidth = (drawingWidth - spacing * stripCount) / stripCount;
            PointF[] points = new PointF[stripCount];

            for (int i = 0; i < stripCount; i++)
            {
                double x = stripWidth * i + spacing * i + xOffset;
                double y = spectrumData[i * spectrumData.Length / stripCount] * scale;   // height
                points[i] = new PointF((float)x, (float)y);
            }

            for (int i = 0; i < stripCount; i++)
            {
                PointF p = points[i];
                float y = yOffset;
                float height = p.Y;

                if (height < 0)
                {
                    y += height;
                    height = -height;
                }

                g.FillRectangle(brush, new RectangleF(p.X, y, stripWidth, height));
            }
        }

        /// <summary>
        /// 画渐变的边框
        /// </summary>
        /// <param name="g"></param>
        /// <param name="inner"></param>
        /// <param name="outer"></param>
        /// <param name="area"></param>
        /// <param name="scale"></param>
        /// <param name="width"></param>
        private void DrawGradientBorder(Graphics g, Color inner, Color outer, Rectangle area, double scale, float width)
        {
            int thickness = (int)(width * scale);
            if (thickness < 1)
                return;

            Rectangle rect = new Rectangle(area.X, area.Y, area.Width, area.Height);

            Rectangle up = new Rectangle(rect.Location, new Size(rect.Width, thickness));
            Rectangle down = new Rectangle(new Point(rect.X, (int)(rect.X + rect.Height - scale * width)), new Size(rect.Width, thickness));
            Rectangle left = new Rectangle(rect.Location, new Size(thickness, rect.Height));
            Rectangle right = new Rectangle(new Point((int)(rect.X + rect.Width - scale * width), rect.Y), new Size(thickness, rect.Height));

            LinearGradientBrush upB = new LinearGradientBrush(up, outer, inner, LinearGradientMode.Vertical);
            LinearGradientBrush downB = new LinearGradientBrush(down, inner, outer, LinearGradientMode.Vertical);
            LinearGradientBrush leftB = new LinearGradientBrush(left, outer, inner, LinearGradientMode.Horizontal);
            LinearGradientBrush rightB = new LinearGradientBrush(right, inner, outer, LinearGradientMode.Horizontal);

            upB.WrapMode = downB.WrapMode = leftB.WrapMode = rightB.WrapMode = WrapMode.TileFlipXY;

            g.FillRectangle(upB, up);
            g.FillRectangle(downB, down);
            g.FillRectangle(leftB, left);
            g.FillRectangle(rightB, right);
        }

        int colorIndex = 0;
        double rotation = 0;
        BufferedGraphics? oldBuffer;
        private void DrawingTimer_Tick(object? sender, EventArgs e)
        {
            if (spectrumData == null)
                return;

            rotation += 0.1;
            colorIndex++;

            Color color1 = allColors[colorIndex % allColors.Length];
            Color color2 = allColors[(colorIndex + 200) % allColors.Length];

            double[] bassArea = Visualizer.TakeSpectrumOfFrequency(spectrumData, capture.WaveFormat.SampleRate, 250);       // 低频区域
            double bassScale = bassArea.Average() * 100;                                                                    // 低音导致的缩放 (比例数)
            double extraScale = Math.Min(drawingPanel.Width, drawingPanel.Height) / 6;                                      // 低音导致的缩放 (乘上窗口大小)

            Rectangle border = new Rectangle(Point.Empty, drawingPanel.Size);

            BufferedGraphics buffer = BufferedGraphicsManager.Current.Allocate(drawingPanel.CreateGraphics(), drawingPanel.ClientRectangle);
            Graphics g = buffer.Graphics;

            if (oldBuffer != null)
            {
                //oldBuffer.Render(buffer.Graphics);      // 如果你想要实现 "留影" 效果, 就取消注释这段代码, 并且将 g.Clear 改为 g.FillRectange(xxx, 半透明的黑色)
                oldBuffer.Dispose();
            }

            using Pen pen = new Pen(Color.Pink);                  // 画音频采样波形用的笔

            g.SmoothingMode = SmoothingMode.HighQuality;          // 嗨嗨害, 那必须得是高质量绘图
            g.Clear(drawingPanel.BackColor);

            //DrawGradientBorder(g, Color.FromArgb(0, color1), color2, border, bassScale, drawingPanel.Width / 10);
            DrawGradientStrips(g, color1, color2, spectrumData, spectrumData.Length, drawingPanel.Width, 0, drawingPanel.Height, 3, -drawingPanel.Height * 50);
            //DrawCircleGradientStrips(g, color1, color2, spectrumData, spectrumData.Length, drawingPanel.Width / 2, drawingPanel.Height / 2, MathF.Min(drawingPanel.Width, drawingPanel.Height) / 4 + extraScale * bassScale, 1, rotation, drawingPanel.Width / 6 * 10);

            //DrawCurve(g, pen, visualizer.SampleData, visualizer.SampleData.Length, drawingPanel.Width, 0, drawingPanel.Height / 2, MathF.Min(drawingPanel.Height / 10, 100));

            buffer.Render();

            oldBuffer = buffer;                                   // 保存一下 buffer (之所以不全局只使用一个 Buffer 是因为,,, 用户可能调整窗口大小, 所以每一帧都必须适应)
        }

        private void MainWindow_Load(object sender, EventArgs e)
        {
            capture.StartRecording();
            dataTimer.Start();
            drawingTimer.Start();
        }

        private void MainWindow_FormClosed(object sender, FormClosedEventArgs e)
        {
            Environment.Exit(0);
        }

        private void DrawingPanel_MouseDoubleClick(object sender, MouseEventArgs e)
        {
            WindowState = WindowState != FormWindowState.Maximized ? FormWindowState.Maximized : FormWindowState.Normal;
            FormBorderStyle = WindowState == FormWindowState.Maximized ? FormBorderStyle.None : FormBorderStyle.Sizable;
        }
    }
}