using System;
using System.Diagnostics;
using System.IO;
using System.Threading.Tasks;
using Unity.Collections.LowLevel.Unsafe;
using UnityEngine;
using UnityEngine.UI;
using Debug = UnityEngine.Debug;

/*
 * 采集摄像头数据，上传rtmp流
 * 需布置对应的rtmp服务器
 * 使用flv 播放器可以拉取视频流
 */
public class RtmpStream : MonoBehaviour
{
    /// <summary>
    /// 抓取摄像头图像的纹理
    /// </summary>
    private Texture2D outputTexture;

    private int frameNum = 0;

    /// <summary>
    /// 推流进程
    /// </summary>
    private Process _proc;

    private Process _pullProcess;

    /// <summary>
    /// 记录是否正在推流
    /// </summary>
    private bool _isRunning = false;

    Camera _camera;

    /// <summary>
    /// 推流地址
    /// </summary>
    string formattedPath = "rtmp://127.0.0.1:1935/live/";

    /// <summary>
    /// 最大码率 单位kb
    /// </summary>
    int maxBitRate = 5000;

    /// <summary>
    /// 推流码,加在formattedPath后面，区分不同流地址
    /// </summary>
    [SerializeField]
    private string streamCode = "default";

    private Texture2D inputTexture;
    [SerializeField] private RawImage image;
    byte[] buffer = new byte[4096];

    private void Awake()
    {
    }

    // Start is called before the first frame update
    void Start()
    {
        _camera = GetComponent<Camera>();
        outputTexture = new Texture2D(_camera.targetTexture.width, _camera.targetTexture.height);
    }

    // Update is called once per frame
    void Update()
    {
        frameNum++;
        if (_isRunning && _camera != null && _camera.isActiveAndEnabled)
        {
            RenderTexture.active = _camera.targetTexture;
            outputTexture.ReadPixels(new Rect(0, 0, _camera.targetTexture.width, _camera.targetTexture.height), 0, 0, true);
            var na = outputTexture.GetRawTextureData<byte>();
            var val = ImageConversion.EncodeNativeArrayToPNG<byte>(na, outputTexture.graphicsFormat, (uint)outputTexture.width, (uint)outputTexture.height);
            SendImage2Pipe(val);
            na.Dispose();
            val.Dispose();
        }
    }


    private void OnDisable()
    {
        StopCapture();
    }

    private void OnDestroy()
    {
        StopCapture();
    }

    /// <summary>
    /// 使用ffmpeg将摄像头图像编码成视频流并推流
    /// </summary>
    private void FfmpegToStream()
    {
        ReadConfig();
        _proc = new Process();

        _proc.StartInfo.RedirectStandardInput = true;
        _proc.StartInfo.RedirectStandardOutput = true;
        _proc.StartInfo.UseShellExecute = false;
        _proc.StartInfo.CreateNoWindow = true;
        _proc.StartInfo.FileName = Application.streamingAssetsPath + "/ffmpeg.exe";
        _proc.StartInfo.Arguments = $"-f image2pipe -use_wallclock_as_timestamps 1  -i - -c:v libx264 -bf 0 -preset ultrafast -tune zerolatency -r 60 -pix_fmt yuv420p -g 20 -s 512X512 -tcp_nodelay 1 -rtmp_flush_interval 1 -maxrate {maxBitRate}k -f flv {GetRtmpServerUrl()}";
        _proc.Start();
    }

    private string GetRtmpServerUrl()
    {
        return formattedPath + streamCode;
    }

    private void CreateProcessGetSteamFromRtmp()
    {
        ReadConfig();
        _pullProcess = new Process();

        _pullProcess.StartInfo.RedirectStandardInput = true;
        _pullProcess.StartInfo.RedirectStandardOutput = true;
        _pullProcess.StartInfo.UseShellExecute = false;
        _pullProcess.StartInfo.CreateNoWindow = true;
        _pullProcess.StartInfo.FileName = Application.streamingAssetsPath + "/ffmpeg.exe";
        _pullProcess.StartInfo.Arguments = $"-i {GetRtmpServerUrl()} -f image2pipe -pix_fmt rgb24 -vcodec rawvideo -";
        _pullProcess.Start();
    }

    /// <summary>
    /// 读取配置文件
    /// </summary>
    private void ReadConfig()
    {
        formattedPath = "rtmp://localhost:1935/live/";
        maxBitRate = 120;
    }

    /// <summary>
    /// 使用ffmpeg将摄像头图像编码成视频流并保存到本地
    /// </summary>
    private void FfmpegToVedio()
    {
        string formattedPath = "D:\\rtmp.mp4";
        int maxBitRate = 5000;

        _proc = new Process();
        _proc.StartInfo.RedirectStandardInput = true;
        _proc.StartInfo.RedirectStandardOutput = true;
        _proc.StartInfo.UseShellExecute = false;
        _proc.StartInfo.CreateNoWindow = true;
        _proc.StartInfo.FileName = @"ffmpeg";
        _proc.StartInfo.Arguments = $"-f image2pipe -use_wallclock_as_timestamps 1 -i - -c:v libx264 -vsync passthrough -s 1920x1080 -maxrate {maxBitRate}k -an -y {formattedPath}";
        _proc.Start();
    }

    /// <summary>
    /// 开始推流
    /// 默认推流地址 rtmp://192.168.48.4:1935/live/
    /// 默认推流码 default
    /// 拉流地址为推流地址+推流码即 rtmp://192.168.48.4:1935/live/default
    /// 推流地址在streamingAssets中的config.ini文件设置，推流码由streamCode变量设置
    /// 使用前先设置streamCode再推流
    /// </summary>
    public void StartCapture()
    {
        if (_isRunning)
            return;
        Debug.Log("Start");
        //FfmpegToVedio();
        FfmpegToStream();
        _isRunning = true;
    }

    /// <summary>
    /// 停止推流
    /// </summary>
    public void StopCapture()
    {
        _isRunning = false;
        if (_proc != null)
        {
            try
            {
                _proc.StartInfo.RedirectStandardInput = false;
                _proc.StartInfo.RedirectStandardOutput = false;
                _proc.StandardInput.Close();
                _proc.StandardOutput.Close();
                _proc.Close();
            }
            catch
            {
                Debug.LogError("stop capture error");
            }
        }
    }


    /// <summary>
    /// 将图片推入管道供编码器使用
    /// </summary>
    /// <param name="bytes"></param>
    private void SendImage2Pipe(Unity.Collections.NativeArray<byte> bytes)
    {
        if (_proc.StartInfo.RedirectStandardInput)
        {
            _proc.StandardInput.BaseStream.Write(bytes);

        }
    }

    private void GetImageFromPipe()
    {
        if (this._pullProcess.StartInfo.RedirectStandardOutput)
        {
            _pullProcess.StandardOutput.BaseStream.BeginRead(buffer, 0, buffer.Length, Callback, buffer);
        }
    }

    private void Callback(IAsyncResult ar)
    {
        var readCount = this._pullProcess.StandardOutput.BaseStream.EndRead(ar);
        if (readCount > 0)
        {
            unsafe
            {
                Debug.LogError(readCount);
                var buffer = (byte[])ar.AsyncState;
                var bytes = new byte[readCount];
                fixed (byte* origin = buffer)
                fixed (byte* destination = bytes)
                    UnsafeUtility.MemCpy(destination, origin, readCount * sizeof(byte));
                this.inputTexture.LoadImage(bytes);
            }
        }
    }

    /// <summary>
    /// unity editor调试
    /// </summary>
    [ContextMenu("start")]
    private void TestStartCaputre()
    {
        StartCapture();
    }

    /// <summary>
    /// unity editor调试
    /// </summary>
    [ContextMenu("stop")]
    private void TestStopCaputre()
    {
        StopCapture();
    }
}