using System.Globalization;

namespace ZB.MOM.WW.ScadaBridge.CLI.Commands;

/// <summary>
/// Helpers for the <c>audit verify-chain</c> subcommand. v1 is a no-op: hash-chain
/// tamper-evidence is deferred to v1.x (see Component-AuditLog.md). The command still
/// validates its <c>--month</c> argument so the surface is stable for v1.x.
/// </summary>
public static class AuditVerifyChainHelpers
{
    /// <summary>
    /// Returns true if <paramref name="month"/> is a well-formed <c>YYYY-MM</c> value
    /// with a real month (01-12). A malformed month (e.g. <c>2026-13</c>) is rejected.
    /// </summary>
    /// <param name="month">The month string to validate in YYYY-MM format.</param>
    /// <returns><c>true</c> if the string is a well-formed YYYY-MM value with a real month; otherwise <c>false</c>.</returns>
    public static bool IsValidMonth(string? month)
        => !string.IsNullOrWhiteSpace(month)
           && DateTime.TryParseExact(month, "yyyy-MM", CultureInfo.InvariantCulture,
               DateTimeStyles.None, out _);
}
