using System;
using System.IO;
using System.Threading;
using System.Threading.Channels;
using System.Threading.Tasks;
using ErsatzTV.Application;
using ErsatzTV.Application.Streaming.Commands;
using ErsatzTV.Core.Interfaces.FFmpeg;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using static LanguageExt.Prelude;

namespace ErsatzTV.Services
{
    public class FFmpegWorkerService : BackgroundService
    {
        private readonly ChannelReader<IFFmpegWorkerRequest> _channel;
        private readonly ILogger<FFmpegWorkerService> _logger;
        private readonly IFFmpegSegmenterService _ffmpegSegmenterService;
        private readonly IServiceScopeFactory _serviceScopeFactory;

        public FFmpegWorkerService(
            ChannelReader<IFFmpegWorkerRequest> channel,
            IServiceScopeFactory serviceScopeFactory,
            ILogger<FFmpegWorkerService> logger,
            IFFmpegSegmenterService ffmpegSegmenterService)
        {
            _channel = channel;
            _serviceScopeFactory = serviceScopeFactory;
            _logger = logger;
            _ffmpegSegmenterService = ffmpegSegmenterService;
        }

        protected override async Task ExecuteAsync(CancellationToken cancellationToken)
        {
            _logger.LogInformation("FFmpeg worker service started");

            await foreach (IFFmpegWorkerRequest request in _channel.ReadAllAsync(cancellationToken))
            {
                try
                {
                    using IServiceScope scope = _serviceScopeFactory.CreateScope();
                    // IMediator mediator = scope.ServiceProvider.GetRequiredService<IMediator>();

                    switch (request)
                    {
                        case TouchFFmpegSession touchFFmpegSession:
                            foreach (DirectoryInfo parent in Optional(Directory.GetParent(touchFFmpegSession.Path)))
                            {
                                _ffmpegSegmenterService.TouchChannel(parent.Name);
                            }

                            break;
                    }
                }
                catch (Exception ex)
                {
                     _logger.LogWarning(ex, "Failed to handle ffmpeg worker request");
                }
            }
        }
    }
}