namespace ZB.MOM.WW.OtOpcUa.AdminUI.Browsing;

/// <summary>
///     Closes a browse session that finished opening after its host went away (R04 L4). Every picker and
///     <c>RawBrowseModal</c> awaited <see cref="IBrowserSessionService.OpenAsync"/> and then stored the token;
///     if the host was disposed (or the modal closed) meanwhile, its teardown had already run with no token,
///     so the session — an OPC UA client session, an MQTT connection, a SQL connection against the plant —
///     stayed open until the reaper's idle TTL (2 min + one 30 s tick).
/// </summary>
public static class BrowseOpenGuard
{
    /// <summary>
    ///     Call right after <see cref="IBrowserSessionService.OpenAsync"/> returns. When the host is gone it
    ///     closes the new session (fire-and-forget, like the hosts' own teardown) and returns
    ///     <see langword="true"/>, telling the caller not to adopt the token.
    /// </summary>
    /// <param name="result">The open result.</param>
    /// <param name="hostGone">Whether the host was disposed (or closed) while the open was in flight.</param>
    /// <param name="service">The browse service the session was opened on.</param>
    /// <returns><see langword="true"/> when the caller must drop the result.</returns>
    public static bool CloseIfOrphaned(BrowseOpenResult result, bool hostGone, IBrowserSessionService service)
    {
        if (!hostGone) return false;
        if (result.Ok && result.Token != Guid.Empty)
        {
            // Never block (or throw into) a dead host's continuation on a slow remote close.
            _ = CloseQuietlyAsync(service, result.Token);
        }

        return true;
    }

    private static async Task CloseQuietlyAsync(IBrowserSessionService service, Guid token)
    {
        try
        {
            await service.CloseAsync(token).ConfigureAwait(false);
        }
        catch
        {
            // The reaper still bounds a session whose close failed.
        }
    }
}