using Grpc.Core;

namespace Svrnty.CQRS.Altcha.Grpc;

/// <summary>
/// Helper that builds gRPC call metadata (an <c>Authorization</c> header)
/// from <see cref="AltchaGrpcOptions.TokenProvider"/>. Kept as a separate
/// shared helper so the verifier and challenge provider apply identical
/// rules.
/// </summary>
internal static class AltchaCallCredentials
{
    public static async Task<Metadata?> BuildMetadataAsync(AltchaGrpcOptions options, CancellationToken cancellationToken)
    {
        if (options.TokenProvider is null)
            return null;

        var token = await options.TokenProvider(cancellationToken);
        if (string.IsNullOrWhiteSpace(token))
            return null;

        return new Metadata
        {
            { "Authorization", $"Bearer {token}" }
        };
    }
}