using System;
using System.Threading;
using System.Threading.Tasks;
using GmRelay.Shared.Features.Sessions.CreateSession.Wizard;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace GmRelay.Bot.Features.Sessions.CreateSession.Wizard;

public sealed class WizardDraftCleanupService : BackgroundService
{
    private static readonly TimeSpan TickInterval = TimeSpan.FromMinutes(1);

    private readonly IWizardDraftRepository _drafts;
    private readonly ILogger<WizardDraftCleanupService> _log;

    public WizardDraftCleanupService(
        IWizardDraftRepository drafts,
        ILogger<WizardDraftCleanupService> log)
    {
        _drafts = drafts;
        _log = log;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        using var timer = new PeriodicTimer(TickInterval);
        try
        {
            while (await timer.WaitForNextTickAsync(stoppingToken))
            {
                await RunOnceAsync(stoppingToken);
            }
        }
        catch (OperationCanceledException)
        {
            // graceful shutdown
        }
    }

    internal async Task RunOnceAsync(CancellationToken ct)
    {
        try
        {
            var deleted = await _drafts.DeleteExpiredAsync(ct);
            if (deleted > 0)
            {
                _log.LogInformation("Wizard cleanup deleted {Count} expired drafts", deleted);
            }
        }
        catch (OperationCanceledException) when (ct.IsCancellationRequested)
        {
            throw;
        }
        catch (Exception ex)
        {
            _log.LogError(ex, "Wizard cleanup tick failed");
        }
    }
}