using AForge.Video;
using AForge.Video.DirectShow;
using AIDiagnosisDemo.Infrastucture;
using System;
using System.Drawing;
using System.Linq;
using System.Threading;

namespace AIDiagnosisDemo.Service
{
    internal class VideoCapturePlayer : IPlayer
    {
        private readonly string _deviceId;
        private readonly object _deviceLocker = new object();
        private int _startTickCount;
        private int _displayCount;
        private int _fps;

        /// <summary>
        /// 接收到图像输入的事件
        /// </summary>
        public event EventHandler<Bitmap> InputFrameReceived;

        /// <summary>
        /// FPS变更的事件
        /// </summary>
        public event EventHandler<int> FPSChanged;

        private VideoCaptureDevice _videoCaptureDevice;

        /// <summary>
        /// VideoPlayer构造函数
        /// </summary>
        /// <param name="deviceId">Device Id</param>
        public VideoCapturePlayer(string deviceId)
        {
            _deviceId = deviceId;
        }

        /// <summary>
        /// 播放
        /// </summary>
        /// <param name="isVideo">是视频为True，是图片为False</param>
        /// <returns>播放成功为True，播放失败为False</returns>
        public bool Play()
        {
            lock (_deviceLocker)
            {
                try
                {
                    var videoFilterInfos = new FilterInfoCollection(FilterCategory.VideoInputDevice).OfType<FilterInfo>();
                    if (videoFilterInfos.FirstOrDefault(i => i.MonikerString == _deviceId) == null)
                    {
                        Logger.Info("Video Device is Empty!!!");
                        return false;
                    }
                    _videoCaptureDevice = new VideoCaptureDevice(_deviceId);
                    _videoCaptureDevice.NewFrame += OnNewFrame;
                    _startTickCount = -1;
                    _videoCaptureDevice.Start();
                    return true;
                }
                catch
                {
                    _videoCaptureDevice = null;
                    Logger.Info("Video Device Play Fail!!!");
                }
                return false;
            }
        }

        private void OnNewFrame(object sender, NewFrameEventArgs eventArgs)
        {
            if (_startTickCount == -1)
            {
                _displayCount = 0;
                _startTickCount = Environment.TickCount;
            }
            else
            {
                var currentTickCount = Environment.TickCount;
                var fpsTimeUsed = currentTickCount - _startTickCount;
                _displayCount++;
                if (fpsTimeUsed > 1000)
                {
                    var fps = (int)((double)_displayCount / fpsTimeUsed * 1000);
                    if (_fps != fps)
                    {
                        _fps = fps;
                        FPSChanged?.Invoke(this, _fps);
                    }
                    _startTickCount = currentTickCount;
                    _displayCount = 0;
                }
            }
            InputFrameReceived?.Invoke(this, eventArgs.Frame);
        }

        /// <summary>
        /// 停止播放
        /// </summary>
        public void Stop()
        {
            lock (_deviceLocker)
            {
                if (_videoCaptureDevice == null)
                {
                    return;
                }
                try
                {
                    _videoCaptureDevice.NewFrame -= OnNewFrame;
                    if (_videoCaptureDevice.IsRunning)
                    {
                        DoStop();
                    }
                }
                catch
                {
                }
                finally
                {
                    _videoCaptureDevice = null;
                }
            }
        }

        private void DoStop()
        {
            var stopThread = new Thread(() =>
            {
                try
                {
                    _videoCaptureDevice.SignalToStop();
                    _videoCaptureDevice.WaitForStop();
                }
                catch
                {
                }
            });
            stopThread.Start();
            try
            {
                if (!stopThread.Join(2000))
                {
                    stopThread.Abort();
                }
            }
            catch
            {
            }
        }

        /// <summary>
        /// 继续播放
        /// </summary>
        public void Continue()
        {
            Play();
        }

        /// <summary>
        /// 暂停播放
        /// </summary>
        public void Pause()
        {
            Stop();
        }
    }
}