using System.Threading;
using Microsoft.Extensions.DependencyInjection;
using NCrontab;
using LCU.Api.Internal.DispatcherSharedLib.Utilities;
using LCU.Api.Internal.Dispatcher.Configurations;
using LCU.Api.Internal.Dispatcher.Services.DispatcherOperationServices;
using LCU.Library.Internal.LCUHostedService.LCUBackgroundService;
namespace LCU.Api.Internal.Dispatcher.HostedServices;

public class JobSchedulerHostedService : LCUBackgroundService, IJobSchedulerHostedService
{
    private readonly ApiConfiguration _apiConfiguration;
    private readonly IServiceScopeFactory _scopeFactory;
    private CancellationToken _cancellationToken;

    public JobSchedulerHostedService(IServiceScopeFactory scopeFactory,
                                  ApiConfiguration apiConfiguration)
    {
        _scopeFactory = scopeFactory;
        _apiConfiguration = apiConfiguration;
        _cancellationToken = new CancellationToken();
    }

    protected override async Task ExecuteAsync(CancellationToken cancellationToken)
    {
		if (!_apiConfiguration.FeatureFlags.RunJobSchedulerHostedService)
		{
			Log.Error("Job Scheduler Hosted Service is disabled by feature flag. Service not started.");
			return;
		}

		Log.Debug("Dispatcher's Job Schedule Hosted Service is starting.");
        try
        {
            while (!cancellationToken.IsCancellationRequested)
            {
                await Task.Delay(_apiConfiguration.DefaultDelayMilliseconds, cancellationToken); // wait until next time

                using (var scope = _scopeFactory.CreateAsyncScope())
                {
                    Log.Debug("Running Job Schedule Service");
                    await scope.ServiceProvider.GetRequiredService<IJobScheduleService>().PerformSchedule(_cancellationToken);
                }
            }
        }
        catch(OperationCanceledException taskCanceledEx)
        {
            Log.Error(taskCanceledEx, $"Manual start/stop of Dispatcher's Job Scheduler Hosted Service was initiated.");
        }
        catch (Exception exception)
        {
            Log.Error(exception,
                "Error trying to startup main thread for Dispatcher's Job Schedule Hosted Service");
        }

        Log.Debug("Dispatcher's Job Schedule Hosted Service is stopping.");
    }
}