DotNetCore.SKIT.FlurlHttpClient.Wechat/src/SKIT.FlurlHttpClient.Wechat.OpenAI/Settings/Credentials.cs

using System;

namespace SKIT.FlurlHttpClient.Wechat.OpenAI.Settings
{
    public sealed class Credentials
    {
        /// <summary>
        /// 初始化客户端时 <see cref="WechatOpenAIClientOptions.AppId"/> / <see cref="WechatChatbotClientOptions.AppId"/> 的副本。
        /// </summary>
        public string AppId { get; }

        /// <summary>
        /// 初始化客户端时 <see cref="WechatOpenAIClientOptions.Token"/> / <see cref="WechatChatbotClientOptions.Token"/> 的副本。
        /// </summary>
        public string Token { get; }

        /// <summary>
        /// 初始化客户端时 <see cref="WechatOpenAIClientOptions.EncodingAESKey"/> / <see cref="WechatChatbotClientOptions.EncodingAESKey"/> 的副本。
        /// </summary>
        public string EncodingAESKey { get; }

        internal Credentials(WechatOpenAIClientOptions options)
        {
            if (options is null) throw new ArgumentNullException(nameof(options));

            AppId = options.AppId;
            Token = options.Token;
            EncodingAESKey = PadEncodingAESKey(options.EncodingAESKey);
        }

        internal Credentials(WechatChatbotClientOptions options)
        {
            if (options is null) throw new ArgumentNullException(nameof(options));

            AppId = options.AppId;
            Token = options.Token;
            EncodingAESKey = PadEncodingAESKey(options.EncodingAESKey);
        }

        private string PadEncodingAESKey(string encodingAESKey)
        {
            // AES 密钥的长度不是 4 的倍数需要补齐，确保其始终为有效的 Base64 字符串
            const int MULTI = 4;
            int tLen = encodingAESKey.Length;
            int tRem = tLen % MULTI;
            if (tRem > 0)
            {
                encodingAESKey = encodingAESKey.PadRight(tLen - tRem + MULTI, '=');
            }

            return encodingAESKey;
        }
    }
}