using System.Data;
using System.Security.Cryptography;
using System.Text;

namespace Net6Demo_Api.Util
{
    public static partial class Extention
    {
        /// <summary>
        /// 转换为MD5加密后的字符串（默认加密为32位）
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string ToMD5String(this string str)
        {
            MD5 md5 = MD5.Create();
            byte[] inputBytes = Encoding.UTF8.GetBytes(str);
            byte[] hashBytes = md5.ComputeHash(inputBytes);

            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < hashBytes.Length; i++)
            {
                sb.Append(hashBytes[i].ToString("x2"));
            }
            md5.Dispose();

            return sb.ToString();
        }

        /// <summary>
        /// 转换为MD5加密后的字符串（16位）
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string ToMD5String16(this string str)
        {
            return str.ToMD5String().Substring(8, 16);
        }

        /// <summary>
        /// Base64加密
        /// 注:默认采用UTF8编码
        /// </summary>
        /// <param name="source">待加密的明文</param>
        /// <returns>加密后的字符串</returns>
        public static string Base64Encode(this string source)
        {
            return Base64Encode(source, Encoding.UTF8);
        }

        /// <summary>
        /// Base64加密
        /// </summary>
        /// <param name="source">待加密的明文</param>
        /// <param name="encoding">加密采用的编码方式</param>
        /// <returns></returns>
        public static string Base64Encode(this string source, Encoding encoding)
        {
            string encode = string.Empty;
            byte[] bytes = encoding.GetBytes(source);
            try
            {
                encode = Convert.ToBase64String(bytes);
            }
            catch
            {
                encode = source;
            }
            return encode;
        }

        /// <summary>
        /// Base64解密
        /// 注:默认使用UTF8编码
        /// </summary>
        /// <param name="result">待解密的密文</param>
        /// <returns>解密后的字符串</returns>
        public static string Base64Decode(this string result)
        {
            return Base64Decode(result, Encoding.UTF8);
        }

        /// <summary>
        /// Base64解密
        /// </summary>
        /// <param name="result">待解密的密文</param>
        /// <param name="encoding">解密采用的编码方式，注意和加密时采用的方式一致</param>
        /// <returns>解密后的字符串</returns>
        public static string Base64Decode(this string result, Encoding encoding)
        {
            string decode = string.Empty;
            byte[] bytes = Convert.FromBase64String(result);
            try
            {
                decode = encoding.GetString(bytes);
            }
            catch
            {
                decode = result;
            }
            return decode;
        }

        /// <summary>
        /// Base64Url编码
        /// </summary>
        /// <param name="text">待编码的文本字符串</param>
        /// <returns>编码的文本字符串</returns>
        public static string Base64UrlEncode(this string text)
        {
            var plainTextBytes = Encoding.UTF8.GetBytes(text);
            var base64 = Convert.ToBase64String(plainTextBytes).Replace('+', '-').Replace('/', '_').TrimEnd('=');

            return base64;
        }

        /// <summary>
        /// Base64Url解码
        /// </summary>
        /// <param name="base64UrlStr">使用Base64Url编码后的字符串</param>
        /// <returns>解码后的内容</returns>
        public static string Base64UrlDecode(this string base64UrlStr)
        {
            base64UrlStr = base64UrlStr.Replace('-', '+').Replace('_', '/');
            switch (base64UrlStr.Length % 4)
            {
                case 2:
                    base64UrlStr += "==";
                    break;
                case 3:
                    base64UrlStr += "=";
                    break;
            }
            var bytes = Convert.FromBase64String(base64UrlStr);

            return Encoding.UTF8.GetString(bytes);
        }

        /// <summary>
        /// 计算SHA1摘要
        /// 注：默认使用UTF8编码
        /// </summary>
        /// <param name="str">字符串</param>
        /// <returns></returns>
        public static byte[] ToSHA1Bytes(this string str)
        {
            return str.ToSHA1Bytes(Encoding.UTF8);
        }

        /// <summary>
        /// 计算SHA1摘要
        /// </summary>
        /// <param name="str">字符串</param>
        /// <param name="encoding">编码</param>
        /// <returns></returns>
        public static byte[] ToSHA1Bytes(this string str, Encoding encoding)
        {
            SHA1 sha1 = SHA1.Create();
            byte[] inputBytes = encoding.GetBytes(str);
            byte[] outputBytes = sha1.ComputeHash(inputBytes);

            return outputBytes;
        }

        /// <summary>
        /// 转为SHA1哈希加密字符串
        /// 注：默认使用UTF8编码
        /// </summary>
        /// <param name="str">字符串</param>
        /// <returns></returns>
        public static string ToSHA1String(this string str)
        {
            return str.ToSHA1String(Encoding.UTF8);
        }

        /// <summary>
        /// 转为SHA1哈希
        /// </summary>
        /// <param name="str">字符串</param>
        /// <param name="encoding">编码</param>
        /// <returns></returns>
        public static string ToSHA1String(this string str, Encoding encoding)
        {
            byte[] sha1Bytes = str.ToSHA1Bytes(encoding);
            string resStr = BitConverter.ToString(sha1Bytes);
            return resStr.Replace("-", "").ToLower();
        }

        /// <summary>
        /// SHA256加密
        /// </summary>
        /// <param name="str">字符串</param>
        /// <returns></returns>
        public static string ToSHA256String(this string str)
        {
            byte[] bytes = Encoding.UTF8.GetBytes(str);
            byte[] hash = SHA256.Create().ComputeHash(bytes);

            StringBuilder builder = new StringBuilder();
            for (int i = 0; i < hash.Length; i++)
            {
                builder.Append(hash[i].ToString("x2"));
            }

            return builder.ToString();
        }

        /// <summary>
        /// HMACSHA256算法
        /// </summary>
        /// <param name="text">内容</param>
        /// <param name="secret">密钥</param>
        /// <returns></returns>
        public static string ToHMACSHA256String(this string text, string secret)
        {
            secret = secret ?? "";
            byte[] keyByte = Encoding.UTF8.GetBytes(secret);
            byte[] messageBytes = Encoding.UTF8.GetBytes(text);
            using (var hmacsha256 = new HMACSHA256(keyByte))
            {
                byte[] hashmessage = hmacsha256.ComputeHash(messageBytes);
                return Convert.ToBase64String(hashmessage).Replace('+', '-').Replace('/', '_').TrimEnd('=');
            }
        }
    }
}