using System;

namespace SoundForce.ApiSigner
{
    /// <summary>
    /// 签名算法类型
    /// </summary>
    public enum SignatureAlgorithm
    {
        /// <summary>
        /// MD5算法（默认、最快）
        /// </summary>
        Md5,

        /// <summary>
        /// SHA1算法
        /// </summary>
        Sha1,

        /// <summary>
        /// SHA256算法
        /// </summary>
        Sha256,

        /// <summary>
        /// HMAC-SHA256算法（最安全）
        /// </summary>
        HmacSha256
    }

    /// <summary>
    /// 签名算法扩展方法
    /// </summary>
    public static class SignatureAlgorithmExtensions
    {
        /// <summary>
        /// 从字符串解析算法类型
        /// </summary>
        /// <param name="algorithm">算法字符串</param>
        /// <returns>签名算法枚举</returns>
        /// <exception cref="ArgumentException">如果算法无效</exception>
        public static SignatureAlgorithm FromString(string? algorithm)
        {
            if (string.IsNullOrEmpty(algorithm))
                return SignatureAlgorithm.Md5;

            return algorithm.ToUpperInvariant() switch
            {
                "MD5" => SignatureAlgorithm.Md5,
                "SHA1" => SignatureAlgorithm.Sha1,
                "SHA256" => SignatureAlgorithm.Sha256,
                "HMAC_SHA256" => SignatureAlgorithm.HmacSha256,
                "HMACSHA256" => SignatureAlgorithm.HmacSha256,
                "HMAC-SHA256" => SignatureAlgorithm.HmacSha256,
                _ => throw new ArgumentException($"无效的签名算法: {algorithm}", nameof(algorithm))
            };
        }

        /// <summary>
        /// 获取算法的字符串表示
        /// </summary>
        /// <param name="algorithm">签名算法</param>
        /// <returns>算法的字符串表示</returns>
        public static string ToString(this SignatureAlgorithm algorithm)
        {
            return algorithm switch
            {
                SignatureAlgorithm.Md5 => "MD5",
                SignatureAlgorithm.Sha1 => "SHA1",
                SignatureAlgorithm.Sha256 => "SHA256",
                SignatureAlgorithm.HmacSha256 => "HMAC-SHA256",
                _ => "UNKNOWN"
            };
        }
    }
}