using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using System.Threading.Tasks.Dataflow;

namespace ActionBlockTest
{
    public class Worker : BackgroundService
    {
        private readonly ILogger<Worker> _logger;

        private ActionBlock<int> actionBlock;

        public Worker(ILogger<Worker> logger)
        {
            _logger = logger;
        }
        public override Task StartAsync(CancellationToken cancellationToken)
        {

            FileStream fileStream = new FileStream("./test.txt", FileMode.OpenOrCreate);
            fileStream.Seek(0, SeekOrigin.Current);

            StreamWriter streamWriter = new StreamWriter(fileStream);

            for (int i = 0; i < 2000; i++)
            {
                streamWriter.WriteLine("{\"seq\": \"" + i + "\",\"camName\": \"¿ØÖÆÊÒ_Ïñ»ú1_ǹ»ú\",\"presetCode\": \"1\"},");

            }
            streamWriter.Flush();
            streamWriter.Close();

            actionBlock = new ActionBlock<int>(
                async e => {  Task.Delay(1000).Wait(); Console.WriteLine(e); },
                new ExecutionDataflowBlockOptions()
                { MaxDegreeOfParallelism = 1, MaxMessagesPerTask = 10 }
                );
            return base.StartAsync(cancellationToken);
        }
        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            int index = 0;
            while (!stoppingToken.IsCancellationRequested)
            {
                //_logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
                actionBlock.Post(index++);
                MemoryStream memoryStream = new MemoryStream();
                StreamWriter streamWriter = new StreamWriter(memoryStream);
                await Task.Delay(10, stoppingToken);
            }
        }
    }
}