using Microsoft.DirectX.DirectSound;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
//————————————————
//版权声明：本文为CSDN博主「zuoyefeng1990」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
//原文链接：https://blog.csdn.net/zuoyefeng1990/article/details/71158111

namespace ZSMusic.Winform
{
    public class SoundRecord
    {
        #region 成员数据
        private Capture mCapDev = null;              // 音频捕捉设备
        private CaptureBuffer mRecBuffer = null;     // 缓冲区对象
        private WaveFormat mWavFormat;               // 录音的格式

        private int mNextCaptureOffset = 0;         // 该次录音缓冲区的起始点
        private int mSampleCount = 0;               // 录制的样本数目

        private Notify mNotify = null;               // 消息通知对象
        public const int cNotifyNum = 16;           // 通知的个数
        private int mNotifySize = 0;                // 每次通知大小
        private int mBufferSize = 0;                // 缓冲队列大小
        private Thread mNotifyThread = null;                 // 处理缓冲区消息的线程
        private AutoResetEvent mNotificationEvent = null;    // 通知事件

        private string mFileName = string.Empty;     // 文件保存路径
        private FileStream mWaveFile = null;         // 文件流
        private BinaryWriter mWriter = null;         // 写文件
        #endregion
        public SoundRecord()
        {
            //初始化音频捕捉设备  
            InitCaptureDevice();
            //设定录音格式  
            mWavFormat = CreateWaveFormat();
        }
        #region 对外操作函数
        /// <summary>  
        /// 创建录音格式,此处使用16bit,16KHz,Mono的录音格式  
        /// <summary>  
        private WaveFormat CreateWaveFormat()
        {
            WaveFormat format = new WaveFormat();
            format.FormatTag = WaveFormatTag.Pcm;   // PCM  
            format.SamplesPerSecond = 16000;        // 采样率：16KHz  
            format.BitsPerSample = 16;              // 采样位数：16Bit  
            format.Channels = 1;                    // 声道：Mono  
            format.BlockAlign = (short)(format.Channels * (format.BitsPerSample / 8));  // 单位采样点的字节数   
            format.AverageBytesPerSecond = format.BlockAlign * format.SamplesPerSecond;
            return format;
            // 按照以上采样规格，可知采样1秒钟的字节数为 16000*2=32000B 约为31K  
        }
        /// <summary>  
        /// 设定录音结束后保存的文件,包括路径  
        /// </summary>  
        /// <param name="filename">保存wav文件的路径名</param>  
        public void SetFileName(string filename)
        {
            mFileName = filename;
        }

        /// <summary>  
        /// 开始录音  
        /// </summary>  
        public void RecStart()
        {
            // 创建录音文件  
            CreateSoundFile();
            // 创建一个录音缓冲区，并开始录音  
            CreateCaptureBuffer();
            // 建立通知消息,当缓冲区满的时候处理方法  
            InitNotifications();
            mRecBuffer.Start(true);
        }
        /// <summary>  
        /// 停止录音  
        /// </summary>  
        public void RecStop()
        {
            mRecBuffer.Stop();      // 调用缓冲区的停止方法，停止采集声音  
            if (null != mNotificationEvent)
                mNotificationEvent.Set();       //关闭通知  
            mNotifyThread.Abort();  //结束线程  
            RecordCapturedData();   // 将缓冲区最后一部分数据写入到文件中  

            // 写WAV文件尾  
            mWriter.Seek(4, SeekOrigin.Begin);
            mWriter.Write((int)(mSampleCount + 36));   // 写文件长度  
            mWriter.Seek(40, SeekOrigin.Begin);
            mWriter.Write(mSampleCount);                // 写数据长度  

            mWriter.Close();
            mWaveFile.Close();
            mWriter = null;
            mWaveFile = null;
        }
        #endregion


        #region 对内操作函数
        /// <summary>
        /// 初始化录音设备,此处使用主录音设备.
        /// </summary>
        /// <returns>调用成功返回true,否则返回false</returns>
        private bool InitCaptureDevice()
        {
            //获取默认音频捕捉设备
            CaptureDevicesCollection devices = new CaptureDevicesCollection();  // 枚举音频捕捉设备
            Guid deviceGuid = Guid.Empty;
            if (devices.Count > 0)
                deviceGuid = devices[0].DriverGuid;
            else
            {
                //MessageBox.Show("系统中没有音频捕捉设备");
                return false;
            }

            // 用指定的捕捉设备创建Capture对象
            try
            {
                mCapDev = new Capture(deviceGuid);
            }
            catch (Exception e)
            {//MessageBox.Show(e.ToString());
                return false;
            }
            return true;
        }

        /// <summary>
        /// 创建录音使用的缓冲区
        /// </summary>
        private void CreateCaptureBuffer()
        {
            // 缓冲区的描述对象
            CaptureBufferDescription bufferdescription = new CaptureBufferDescription();
            if (null != mNotify)
            {
                mNotify.Dispose();
                mNotify = null;
            }
            if (null != mRecBuffer)
            {
                mRecBuffer.Dispose();
                mRecBuffer = null;
            }
            // 设定通知的大小,默认为1s钟
            mNotifySize = (1024 > mWavFormat.AverageBytesPerSecond / 8) ? 1024 : (mWavFormat.AverageBytesPerSecond / 8);
            mNotifySize -= mNotifySize % mWavFormat.BlockAlign;
            // 设定缓冲区大小
            mBufferSize = mNotifySize * cNotifyNum;
            // 创建缓冲区描述
            bufferdescription.BufferBytes = mBufferSize;
            bufferdescription.Format = mWavFormat;           // 录音格式
            // 创建缓冲区
            mRecBuffer = new CaptureBuffer(bufferdescription, mCapDev);
            mNextCaptureOffset = 0;
        }

        /// <summary>
        /// 初始化通知事件,将原缓冲区分成16个缓冲队列,在每个缓冲队列的结束点设定通知点.
        /// </summary>
        /// <returns>是否成功</returns>
        private bool InitNotifications()
        {
            if (null == mRecBuffer)
            {
                // MessageBox.Show("未创建录音缓冲区");
                return false;
            }
            // 创建一个通知事件,当缓冲队列满了就激发该事件.
            mNotificationEvent = new AutoResetEvent(false);
            // 创建一个线程管理缓冲区事件
            if (null == mNotifyThread)
            {
                mNotifyThread = new Thread(new ThreadStart(WaitThread));
                mNotifyThread.Start();
            }
            // 设定通知的位置
            BufferPositionNotify[] PositionNotify = new BufferPositionNotify[cNotifyNum + 1];
            for (int i = 0; i < cNotifyNum; i++)
            {
                PositionNotify[i].Offset = (mNotifySize * i) + mNotifySize - 1;
                PositionNotify[i].EventNotifyHandle = mNotificationEvent.SafeWaitHandle.DangerousGetHandle();
            }
            mNotify = new Notify(mRecBuffer);
            mNotify.SetNotificationPositions(PositionNotify, cNotifyNum);
            return true;
        }

        /// <summary>
        /// 接收缓冲区满消息的处理线程
        /// </summary>
        private void WaitThread()
        {
            while (true)
            {
                // 等待缓冲区的通知消息
                mNotificationEvent.WaitOne(Timeout.Infinite, true);
                // 录制数据
                RecordCapturedData();
            }
        }

        /// <summary>
        /// 将录制的数据写入wav文件
        /// </summary>
        private void RecordCapturedData()
        {
            byte[] CaptureData = null;
            int ReadPos = 0, CapturePos = 0, LockSize = 0;
            mRecBuffer.GetCurrentPosition(out CapturePos, out ReadPos);
            LockSize = ReadPos - mNextCaptureOffset;
            if (LockSize < 0)       // 因为是循环的使用缓冲区，所以有一种情况下为负：当文以载读指针回到第一个通知点，而Ibuffeoffset还在最后一个通知处
                LockSize += mBufferSize;
            LockSize -= (LockSize % mNotifySize);   // 对齐缓冲区边界,实际上由于开始设定完整,这个操作是多余的.
            if (0 == LockSize)
                return;

            // 读取缓冲区内的数据
            CaptureData = (byte[])mRecBuffer.Read(mNextCaptureOffset, typeof(byte), LockFlag.None, LockSize);
            // 写入Wav文件
            mWriter.Write(CaptureData, 0, CaptureData.Length);
            // 更新已经录制的数据长度.
            mSampleCount += CaptureData.Length;
            // 移动录制数据的起始点,通知消息只负责指示产生消息的位置,并不记录上次录制的位置
            mNextCaptureOffset += CaptureData.Length;
            mNextCaptureOffset %= mBufferSize; // Circular buffer
        }

        /// <summary>
        /// 创建保存的波形文件,并写入必要的文件头.
        /// </summary>
        private void CreateSoundFile()
        {
            // Open up the wave file for writing.
            mWaveFile = new FileStream(mFileName, FileMode.Create);
            mWriter = new BinaryWriter(mWaveFile);
            /************************************************************************** 
               Here is where the file will be created. A 
               wave file is a RIFF file, which has chunks 
               of data that describe what the file contains. 
               A wave RIFF file is put together like this: 
               The 12 byte RIFF chunk is constructed like this: 
               Bytes 0 - 3 :  'R' 'I' 'F' 'F' 
               Bytes 4 - 7 :  Length of file, minus the first 8 bytes of the RIFF description. 
                                 (4 bytes for "WAVE" + 24 bytes for format chunk length + 
                                 8 bytes for data chunk description + actual sample data size.) 
                Bytes 8 - 11: 'W' 'A' 'V' 'E' 
                The 24 byte FORMAT chunk is constructed like this: 
                Bytes 0 - 3 : 'f' 'm' 't' ' ' 
                Bytes 4 - 7 : The format chunk length. This is always 16. 
                Bytes 8 - 9 : File padding. Always 1. 
                Bytes 10- 11: Number of channels. Either 1 for mono,  or 2 for stereo. 
                Bytes 12- 15: Sample rate. 
                Bytes 16- 19: Number of bytes per second. 
                Bytes 20- 21: Bytes per sample. 1 for 8 bit mono, 2 for 8 bit stereo or 
                                16 bit mono, 4 for 16 bit stereo. 
                Bytes 22- 23: Number of bits per sample. 
                The DATA chunk is constructed like this: 
                Bytes 0 - 3 : 'd' 'a' 't' 'a' 
                Bytes 4 - 7 : Length of data, in bytes. 
                Bytes 8 -: Actual sample data. 
              ***************************************************************************/
            // Set up file with RIFF chunk info.
            char[] ChunkRiff = { 'R', 'I', 'F', 'F' };
            char[] ChunkType = { 'W', 'A', 'V', 'E' };
            char[] ChunkFmt = { 'f', 'm', 't', ' ' };
            char[] ChunkData = { 'd', 'a', 't', 'a' };

            short shPad = 1;                // File padding
            int nFormatChunkLength = 0x10;  // Format chunk length.
            int nLength = 0;                // File length, minus first 8 bytes of RIFF description. This will be filled in later.
            short shBytesPerSample = 0;     // Bytes per sample.

            // 一个样本点的字节数目
            if (8 == mWavFormat.BitsPerSample && 1 == mWavFormat.Channels)
                shBytesPerSample = 1;
            else if ((8 == mWavFormat.BitsPerSample && 2 == mWavFormat.Channels) || (16 == mWavFormat.BitsPerSample && 1 == mWavFormat.Channels))
                shBytesPerSample = 2;
            else if (16 == mWavFormat.BitsPerSample && 2 == mWavFormat.Channels)
                shBytesPerSample = 4;

            // RIFF 块
            mWriter.Write(ChunkRiff);
            mWriter.Write(nLength);
            mWriter.Write(ChunkType);

            // WAVE块
            mWriter.Write(ChunkFmt);
            mWriter.Write(nFormatChunkLength);
            mWriter.Write(shPad);
            mWriter.Write(mWavFormat.Channels);
            mWriter.Write(mWavFormat.SamplesPerSecond);
            mWriter.Write(mWavFormat.AverageBytesPerSecond);
            mWriter.Write(shBytesPerSample);
            mWriter.Write(mWavFormat.BitsPerSample);

            // 数据块
            mWriter.Write(ChunkData);
            mWriter.Write((int)0);   // The sample length will be written in later.
        }
        #endregion
    }
}