using ClaudeDo.Worker.Config;

namespace ClaudeDo.Worker.Runner;

// Stops interactive/streaming sessions that have gone idle. Interactive `claude` processes wait
// on stdin and never exit on their own, and there is no client-disconnect teardown — so an
// abandoned chat (UI closed, navigated away, crashed) keeps its claude.exe (+ conhost) alive for
// the worker's entire lifetime. Under a long-running autostart worker these pile up (observed:
// ~170 child processes). This sweep reaps the idle ones.
public sealed class IdleSessionReaper : BackgroundService
{
    private static readonly TimeSpan SweepInterval = TimeSpan.FromMinutes(5);

    private readonly LiveSessionRegistry _registry;
    private readonly WorkerConfig _cfg;
    private readonly ILogger<IdleSessionReaper> _logger;

    public IdleSessionReaper(LiveSessionRegistry registry, WorkerConfig cfg, ILogger<IdleSessionReaper> logger)
    {
        _registry = registry;
        _cfg = cfg;
        _logger = logger;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        var idleTimeout = TimeSpan.FromMinutes(_cfg.InteractiveIdleTimeoutMinutes);
        if (idleTimeout <= TimeSpan.Zero)
            return; // reaper disabled

        using var timer = new PeriodicTimer(SweepInterval);
        while (await timer.WaitForNextTickAsync(stoppingToken))
        {
            try
            {
                var reaped = await _registry.ReapIdleAsync(DateTime.UtcNow, idleTimeout);
                if (reaped.Count > 0)
                    _logger.LogInformation(
                        "Reaped {session_count} idle interactive session(s) after {idle_minutes} min: {task_ids}",
                        reaped.Count, _cfg.InteractiveIdleTimeoutMinutes, string.Join(", ", reaped));
            }
            catch (OperationCanceledException) { throw; }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Idle session reap sweep failed");
            }
        }
    }
}