using NAudio.Wave;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Resources;
using System.Text;
using System.Threading.Tasks;
using CDSAE3_Lian_Lian_Kan.Properties;
using NAudio.Wave.SampleProviders;
namespace CDSAE3_Lian_Lian_Kan.Sound
{
    public class Audio_processer
    {
        class Audio_File_Processor
        {
            private WaveChannel32? volumeStream;
            private List<string> audioFiles = new List<string>();
            string base_path;
            int next_song = 0;
            int volume = 90;
            public Audio_File_Processor()
            {
                base_path = AppDomain.CurrentDomain.BaseDirectory;
            }
            internal void set_Albums(string s)=>audioFiles = Settings.musics.TryGetValue(s, out List<string>? val) ? val : new List<string>();
            internal Wave16ToFloatProvider get_next_song()
            {
                volumeStream?.Close();
                string name = audioFiles[next_song];
                next_song++;
                next_song %= audioFiles.Count;
                name = name.Split('.').First().Replace(" ","_").Replace("-","_");
                object obj = Settings.res_Manager.GetObject(name, Settings.res_Culture)!;
                MemoryStream sound = new MemoryStream((byte[])obj);
                MemoryStream ms = new MemoryStream(StreamToBytes(sound));
                var ws = new Mp3FileReader(ms);
                BlockAlignReductionStream blockAlignReductionStream = new BlockAlignReductionStream(ws);
                Wave16ToFloatProvider wave16ToFloatProvider = new Wave16ToFloatProvider(blockAlignReductionStream);
                wave16ToFloatProvider.Volume = volume / 100f;
                return wave16ToFloatProvider;
            }
            internal Wave16ToFloatProvider get_last_song()
            {
                next_song = (next_song - 2 + audioFiles.Count) % audioFiles.Count;
                return get_next_song();
            }
            internal void volume_change(int val)
            {
                volume = val;
                if(volumeStream != null)
                    volumeStream.Volume = volume / 100f;
            }
            internal static byte[] StreamToBytes(Stream stream)
            {
                long originalPosition = 0;

                if (stream.CanSeek)
                {
                    originalPosition = stream.Position;
                    stream.Position = 0;
                }

                try
                {
                    byte[] readBuffer = new byte[4096];

                    int totalBytesRead = 0;
                    int bytesRead;

                    while ((bytesRead = stream.Read(readBuffer, totalBytesRead, readBuffer.Length - totalBytesRead)) > 0)
                    {
                        totalBytesRead += bytesRead;

                        if (totalBytesRead == readBuffer.Length)
                        {
                            int nextByte = stream.ReadByte();
                            if (nextByte != -1)
                            {
                                byte[] temp = new byte[readBuffer.Length * 2];
                                Buffer.BlockCopy(readBuffer, 0, temp, 0, readBuffer.Length);
                                Buffer.SetByte(temp, totalBytesRead, (byte)nextByte);
                                readBuffer = temp;
                                totalBytesRead++;
                            }
                        }
                    }

                    byte[] buffer = readBuffer;
                    if (readBuffer.Length != totalBytesRead)
                    {
                        buffer = new byte[totalBytesRead];
                        Buffer.BlockCopy(readBuffer, 0, buffer, 0, totalBytesRead);
                    }
                    return buffer;
                }
                finally
                {
                    if (stream.CanSeek)
                    {
                        stream.Position = originalPosition;
                    }
                }
            }
            ~Audio_File_Processor()
            {
                volumeStream?.Close();
            }

        }
        private WaveOutEvent songOutputDevice;
        private WaveOutEvent infoOutputDevice;
        Audio_File_Processor audio_File_Processor = new Audio_File_Processor();
        public Audio_processer()
        {
            songOutputDevice = new WaveOutEvent();
            infoOutputDevice = new WaveOutEvent();
            set_albums(get_albums().First());
        }
        private void OnPlaybackStopped(object? sender, StoppedEventArgs e)
        {
            next_song();
            resume_song();
        }
        public void pause_song()=>songOutputDevice.Pause();
        public void resume_song()=>songOutputDevice.Play();
        public void last_song()
        {
            waveOutEvent_Provider(audio_File_Processor.get_last_song());
        }
        public void next_song()
        {
            waveOutEvent_Provider(audio_File_Processor.get_next_song());
        }
        /// <summary>
        /// 切换音乐
        /// </summary>
        /// <param name="waveChannel32"></param>
        private void waveOutEvent_Provider(Wave16ToFloatProvider wave16ToFloatProvider)
        {
            
            songOutputDevice.Stop();
            songOutputDevice.Dispose();
            songOutputDevice = new WaveOutEvent();
            songOutputDevice.Init(wave16ToFloatProvider);
            songOutputDevice.PlaybackStopped += OnPlaybackStopped;
        }
        /// <summary>
        /// 调整音乐音量
        /// </summary>
        /// <param name="val">音量大小 1-100</param>
        public void volume_change(int val)=> audio_File_Processor.volume_change(val);
        public List<string> get_albums() => Settings.musics.Select(x => x.Key).ToList();
        public void set_albums(string s)
        {
            audio_File_Processor.set_Albums(s);
        }
        ~Audio_processer()
        {
            songOutputDevice.Dispose();
            infoOutputDevice.Dispose();
        }
    }
}