namespace UtopiaCanteenSystem.Services;

/// <summary>
/// Maps HRMS <c>employee_rfid_tag.grade_type</c> to <c>menu_item.item_for</c>.
/// Menu rows only use MANAGEMENT / NON_MANAGEMENT; other grades must map to one of those.
/// Contractual and MTO/TE/Intern use the management menu; Unassigned uses non-management.
/// </summary>
public static class HrmsMenuItemForMapping
{
    /// <summary>
    /// Returns MANAGEMENT or NON_MANAGEMENT for menu queries. Never returns empty.
    /// </summary>
    public static string FromGradeType(string? gradeType)
    {
        var compact = ToCompactAlphaNum(gradeType);
        if (string.IsNullOrEmpty(compact))
            return "NON_MANAGEMENT";

        if (compact == "management")
            return "MANAGEMENT";

        if (compact == "nonmanagement")
            return "NON_MANAGEMENT";

        if (compact == "contractual" || compact == "mtoteintern")
            return "MANAGEMENT";

        if (compact == "unassigned")
            return "NON_MANAGEMENT";

        if (compact.StartsWith("non", StringComparison.Ordinal) && compact.Contains("management", StringComparison.Ordinal))
            return "NON_MANAGEMENT";

        // Any other label (e.g. future grade codes) — use non-management menu so items still resolve.
        return "NON_MANAGEMENT";
    }

    /// <summary>Human-readable grade label for Excel export (Management / Non Management).</summary>
    public static string ToExportGradeLabel(string? gradeType)
    {
        return FromGradeType(gradeType) == "MANAGEMENT" ? "Management" : "Non Management";
    }

    private static string ToCompactAlphaNum(string? s)
    {
        if (string.IsNullOrWhiteSpace(s))
            return string.Empty;
        var chars = s.Trim().ToLowerInvariant().Where(char.IsLetterOrDigit).ToArray();
        return new string(chars);
    }
}