using Microsoft.Extensions.Hosting;

namespace OwnerNumberMigration.Migrations;

public class MigrationManager : IMigrationManager
{
    private readonly IHostApplicationLifetime _appLifetime;
    private readonly IList<Task> _migrationTasks = new List<Task>();

    private static readonly IReadOnlySet<TaskStatus> CompletedStatuses = new HashSet<TaskStatus>
    {
        TaskStatus.Faulted,
        TaskStatus.Canceled,
        TaskStatus.RanToCompletion
    };

    public MigrationManager(IHostApplicationLifetime appLifetime)
    {
        _appLifetime = appLifetime;
    }

    public void Start(Task migrationTask)
    {
        _migrationTasks.Add(migrationTask);

        migrationTask.ContinueWith(_ =>
        {
            lock (_migrationTasks)
            {
                if (_migrationTasks.All(t => CompletedStatuses.Contains(t.Status)))
                {
                    _appLifetime.StopApplication();
                }
            }
        });
    }
}