using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Discord;
using Discord.Audio;
using Discord.WebSocket;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace KasinoBot
{
    public class Music
    {
        private IAudioClient AudioClient { get; set; }
        private ISocketMessageChannel TextChannel { get; set; }
        private Queue<MusicInfo> Queue { get; }
        private Stream? CurrentMusicStream { get; set; }
        private Process? CurrentFFmpeg { get; set; }
        private AudioOutStream? CurrentOuAudio { get; set; }

        public Music(SocketGuild guild, ISocketMessageChannel channel, IAudioClient audioClient)
        {
            Queue = new Queue<MusicInfo>();
            TextChannel = channel;
            AudioClient = audioClient;
        }

        public async Task Play(string query, SocketUser user, SocketUserMessage message)
        {
            if (message.Channel != null)
                TextChannel = message.Channel;

            MusicInfo musicInfo = new MusicInfo(query, user);
            //await message.AddReactionAsync(Emoji.Parse("👌"));
            await TextChannel.SendMessageAsync($"Enqueued **\"{musicInfo.Title}\"** *({musicInfo.Duration})*");

            Queue.Enqueue(musicInfo);
            if (Queue.Count == 1)
                await PlayNextMusic();
        }

        public async Task Stop()
        {
            Queue.Clear();
            if (CurrentMusicStream != null)
                CurrentMusicStream.Close();
            await Task.Delay(10);
        }

        public async Task Skip()
        {
            Console.WriteLine("Skipping");
            if (CurrentMusicStream != null)
                CurrentMusicStream.Close();
            await Task.Delay(10);
        }

        private async Task PlayNextMusic()
        {
            if (Queue.Count == 0)
                return;

            try
            {
                var musicInfo = Queue.Peek();

                using (var input = AudioClient.CreatePCMStream(AudioApplication.Music))
                using (CurrentFFmpeg = CreateAudioStream(musicInfo.MediaURL))
                using (CurrentMusicStream = CurrentFFmpeg.StandardOutput.BaseStream)
                {
                    try
                    {
                        await CurrentMusicStream.CopyToAsync(input);
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine("Error CopyToAsync: " + ex.ToString());
                    }
                    finally
                    {
                        Queue.Dequeue();
                        await input.FlushAsync();
                    }
                }
            }
            catch (Exception e)
            {
                await TextChannel.SendMessageAsync($"Error: {e.Message}");
                Console.WriteLine(e);
            }

            await PlayNextMusic();
        }

        private Process CreateAudioStream(string path)
        {
            var p = Process.Start(new ProcessStartInfo
            {
                FileName = "ffmpeg",
                Arguments = $"-hide_banner -loglevel panic -i \"{path}\" -ac 2 -f s16le -ar 48000 pipe:1",
                UseShellExecute = false,
                RedirectStandardOutput = true,
            });

            if (p == null)
                throw new Exception("Could not start ffmpeg. Please make sure ffmpeg is available.");
            else if (p.HasExited)
                throw new Exception("ffmpeg exited with code " + p.ExitCode);

            return p;
        }
    }

    public class MusicInfo
    {
        public string Query { get; }
        public SocketUser User { get; }
        public string Title { get; set; }
        public string Duration { get; set; }
        public string MediaURL { get; set; }
        public string YoutubeURL { get; set; }
        public MusicInfo(string query, SocketUser user)
        {
            Query = query;
            User = user;

            var p = Process.Start(new ProcessStartInfo
            {
                FileName = "youtube-dl",
                Arguments = $"-f bestaudio --dump-json --default-search \"ytsearch\" -g \"{this.Query}\"",
                UseShellExecute = false,
                RedirectStandardOutput = true,
            });

            if (p == null)
                throw new Exception("Could not start youtube-dl. Please make sure youtube-dl is available.");
            else if (p.HasExited)
                throw new Exception("youtube-dl exited with code " + p.ExitCode);

            var output = p.StandardOutput.ReadToEnd();
            p.WaitForExit();

            try
            {
                JToken json = JObject.Parse(output.Split('\n')[1]);
                if (json == null)
                    throw new Exception("Could not parse youtube-dl output.");

                int duration = int.Parse(json["duration"].ToString());
                this.MediaURL = output.Split('\n')[0];
                this.Title = json["title"].ToString();
                this.YoutubeURL = json["webpage_url"].ToString();
                this.Duration = $"{Math.Floor((float)duration / 60)}m {duration % 60}s";
            }
            catch (Exception e)
            {
                throw new Exception("Error parsing information from Youtube-DL: " + e.Message);
            }
        }
    }
}