using ZB.MOM.WW.OtOpcUa.Cluster;

namespace ZB.MOM.WW.OtOpcUa.Host.Configuration;

/// <summary>
///     Names the per-role appsettings overlay (<c>appsettings.{suffix}.json</c>) for a node.
/// </summary>
/// <remarks>
///     The suffix is built from the node's PLAIN roles only. <c>cluster-{ClusterId}</c> roles are mesh-membership
///     tags (and carry a verbatim, operator-chosen ClusterId), not configuration profiles — folding one into the
///     filename produced names like <c>appsettings.admin-cluster-MAIN-driver.json</c> that never exist, so on every
///     node with a cluster role the shipped overlays silently never loaded.
/// </remarks>
internal static class RoleOverlay
{
    /// <summary>
    ///     The overlay filename suffix: the plain (non-cluster) roles, ordinal-sorted and joined with <c>-</c>, or
    ///     <see langword="null"/> when the node has none.
    /// </summary>
    public static string? Suffix(IReadOnlyList<string> gossipedRoles)
    {
        var plain = gossipedRoles
            .Where(r => !string.IsNullOrWhiteSpace(r) && !RoleParser.IsClusterRole(r))
            .OrderBy(r => r, StringComparer.Ordinal)
            .ToList();
        return plain.Count == 0 ? null : string.Join('-', plain);
    }
}