using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace ConsoleApp2.Services;

public class TaskMonitorService : BackgroundService
{
    private readonly IHostApplicationLifetime _lifetime;
    private readonly TaskManager _taskManager;
    private readonly ILogger<TaskMonitorService> _logger;

    public TaskMonitorService(IHostApplicationLifetime lifetime, TaskManager taskManager,
        ILogger<TaskMonitorService> logger)
    {
        _lifetime = lifetime;
        _taskManager = taskManager;
        _logger = logger;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        while (!_taskManager.MainTaskCompleted || _taskManager.RunningTaskCount != 0)
        {
            var running = 0;
            var error = 0;
            var completed = 0;
            var canceled = 0;
            foreach (var task in _taskManager.Tasks)
            {
                switch (task.Status)
                {
                    case TaskStatus.Running:
                        running++;
                        break;
                    case TaskStatus.Canceled:
                        canceled++;
                        break;
                    case TaskStatus.Faulted:
                        error++;
                        break;
                    case TaskStatus.RanToCompletion:
                        completed++;
                        break;
                    default:
                        throw new ArgumentOutOfRangeException();
                }
            }

            _logger.LogInformation(
                "Task monitor: running: {Running}, error: {Error}, completed: {Completed}, canceled: {Canceled}",
                running, error, completed, canceled);
            await Task.Delay(2000);
        }

        _logger.LogInformation("***** All tasks completed *****");
    }
}