namespace EnvelopeGenerator.Application.Services
{
    /// <summary>
    /// Provides extension methods for decoding and extracting information from an envelope receiver ID.
    /// </summary>
    public static class EnvelopeGeneratorExtensions
    {
        /// <summary>
        /// Decodes the envelope receiver ID and extracts the envelope UUID and receiver signature.
        /// </summary>
        /// <param name="envelopeReceiverId">The base64 encoded string containing the envelope UUID and receiver signature.</param>
        /// <returns>A tuple containing the envelope UUID and receiver signature.</returns>
        public static (string EnvelopeUuid, string ReceiverSignature) DecodeEnvelopeReceiverId(this string envelopeReceiverId)
        {
            byte[] bytes = Convert.FromBase64String(envelopeReceiverId);
            string decodedString = System.Text.Encoding.UTF8.GetString(bytes);
            string[] parts = decodedString.Split(new string[] { "::" }, StringSplitOptions.None);

            if (parts.Length > 1)
                return (EnvelopeUuid: parts[0], ReceiverSignature: parts[1]);
            else
                return (string.Empty, string.Empty);
        }

        /// <summary>
        /// Gets the envelope UUID from the decoded envelope receiver ID.
        /// </summary>
        /// <param name="envelopeReceiverId">The base64 encoded string to decode.</param>
        /// <returns>The envelope UUID.</returns>
        public static string GetEnvelopeUuid(this string envelopeReceiverId) => envelopeReceiverId.DecodeEnvelopeReceiverId().EnvelopeUuid;

        /// <summary>
        /// Gets the receiver signature from the decoded envelope receiver ID.
        /// </summary>
        /// <param name="envelopeReceiverId">The base64 encoded string to decode.</param>
        /// <returns>The receiver signature.</returns>
        public static string GetReceiverSignature(this string envelopeReceiverId) => envelopeReceiverId.DecodeEnvelopeReceiverId().ReceiverSignature;
    }
}