#region

using System;
using System.IO;
using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Threading;
using System.Web;
using System.Windows.Forms;
using CSFrameworkV5.Core;
using Newtonsoft.Json;

#endregion

namespace CSFrameworkV5.Language
{
    /// <summary>
    ///     百度翻译
    /// </summary>
    public class BaiduTrans
    {
        private string _appKey;
        private string _secretKey;

        private int _TryCount;

        /// <summary>
        ///     屏蔽默认构造器
        /// </summary>
        private BaiduTrans()
        {
        }

        public BaiduTrans(string appKey, string secretKey)
        {
            _appKey = appKey;
            _secretKey = secretKey;
        }

        //付费接口
        public bool IsNoMoney { get; set; }

        //使用免费翻译
        public bool IsUseFreeAPI { get; set; }

        /// <summary>
        ///     百度翻译免费账号
        /// </summary>
        /// <returns></returns>
        public static BaiduTrans CreateDefault()
        {
            //国鹏免费账号
            var tran =
                new BaiduTrans("20210427000804053", "5ZkKRBKxYyndy7_VhhLS");
            tran.IsUseFreeAPI = true;
            return tran;
        }

        // 计算MD5值
        public static string EncryptString(string str)
        {
            var md5 = MD5.Create();

            // 将字符串转换成字节数组
            var byteOld = Encoding.UTF8.GetBytes(str);
            // 调用加密方法
            var byteNew = md5.ComputeHash(byteOld);
            // 将加密结果转换为字符串
            var sb = new StringBuilder();
            foreach (var b in byteNew)
                // 将字节转换成16进制表示的字符串，
                sb.Append(b.ToString("x2"));

            // 返回加密的字符串
            return sb.ToStringEx();
        }

        /// <summary>
        ///     还原特殊符号
        /// </summary>
        /// <param name="content">原始内容</param>
        /// <param name="baiduTrans">翻译后内容</param>
        /// <returns></returns>
        private static string GetResult(string content, string baiduTrans)
        {
            if (string.IsNullOrWhiteSpace(baiduTrans)) return baiduTrans;

            //下滑线,check_time=检查\u时间
            if (baiduTrans.ToLower().IndexOf(@"\u") > 0)
                baiduTrans = baiduTrans.Replace(@"\u", "_").Replace(@"\U", "_");

            if (baiduTrans.ToLower().IndexOf(@"\ u") > 0 &&
                content.IndexOf("_") > 0)
                baiduTrans = baiduTrans.Replace(@"\ u", "_")
                    .Replace(@"\ U", "_");

            if (baiduTrans.ToLower().IndexOf(@"\ ") > 0 &&
                content.IndexOf("_") > 0)
                baiduTrans = baiduTrans.Replace(@"\ ", "_");

            if (baiduTrans.ToLower().IndexOf(@"\") > 0 &&
                content.IndexOf("_") > 0)
                baiduTrans = baiduTrans.Replace(@"\", "_");

            //VCHAR39==>VCHAR39公司
            if (baiduTrans.LastIndexOf("公司") > 0)
            {
                //尾部是公司
                var ss = baiduTrans.Substring(baiduTrans.LastIndexOf("公司"), 2);
                if (ss == "公司" &&
                    (baiduTrans.ToLower().IndexOf("company") < 0 ||
                     baiduTrans.ToLower().IndexOf("corporation") < 0 ||
                     baiduTrans.ToLower().IndexOf("corp") < 0))
                    baiduTrans = baiduTrans.Replace("公司", "");
            }

            //&#39；单引号，转换为全局单引号
            if (baiduTrans.LastIndexOf("&#39") > 0)
                baiduTrans = baiduTrans.Replace("&#39；", "‘")
                    .Replace("&#39;", "‘").Replace("&#39", "‘");

            return baiduTrans.Trim();
        }

        /// <summary>
        ///     翻译内容
        /// </summary>
        /// <param name="content">内容</param>
        /// <param name="from">源语言</param>
        /// <param name="to">目标语言</param>
        /// <returns></returns>
        public string Tran(string content, string from = "zh",
            string to = "eng")
        {
            if (string.IsNullOrWhiteSpace(content)) return string.Empty;

            //截取左右空格空白字符
            content = content.Trim();

            //如果使用免费翻译API,访问频率受限1s翻译一次
            if (IsUseFreeAPI)
            {
                Application.DoEvents();
                Thread.Sleep(1000);
            }

            //余额不足，不翻译
            if (IsNoMoney) return content;

            var q = content; // 原文
            var rd = new Random();
            var salt = rd.Next(100000).ToStringEx();

            var appId = _appKey; // 改成您的APP ID
            var secretKey = _secretKey; // 改成您的密钥

            //MD5
            var sign = EncryptString(appId + q + salt + secretKey);
            var url = "http://api.fanyi.baidu.com/api/trans/vip/translate?";
            url += "q=" + HttpUtility.UrlEncode(q);
            url += "&from=" + from;
            url += "&to=" + to;
            url += "&appid=" + appId;
            url += "&salt=" + salt;
            url += "&sign=" + sign;
            var request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "GET";
            request.ContentType = "text/html;charset=UTF-8";
            request.UserAgent = null;
            request.Timeout = 6000;
            var response = (HttpWebResponse)request.GetResponse();
            var myResponseStream = response.GetResponseStream();
            var myStreamReader = new StreamReader(myResponseStream,
                Encoding.GetEncoding("utf-8"));
            var retString = myStreamReader.ReadToEnd();
            myStreamReader.Close();
            myResponseStream.Close();

            var data =
                JsonConvert.DeserializeObject<BaiduTransResult>(retString);

            //翻译成功
            if (data != null && data.trans_result != null &&
                data.trans_result.Count > 0)
            {
                var str = data.trans_result[0].dst;

                //HTML转译
                str = HttpUtility.HtmlDecode(str);

                var result = GetResult(content, str); //特殊处理

                _TryCount = 0; //翻译成功，计算器重置

                return result;
            }

            if (data.error_code == "54004")
            {
                //{"error_code":"54004","error_msg":"Please recharge"}
                IsNoMoney = true;

                //SetFreeAccount();
            }
            else if (data.error_code == "54003")
            {
                //54003,Invalid Access Limit
                //SetFreeAccount1();

                //流量限制，尝试最多翻译3次
                _TryCount++;

                if (_TryCount < 5) return Tran(content);
            }
            else if (!string.IsNullOrEmpty(data.error_msg))
            {
                throw new Exception(
                    $"调用百度翻译API发生错误：{data.error_code},{data.error_msg}");
            }

            _TryCount = 0;

            return content;
        }

        public class BaiduTransKey
        {
            public string ApiKey { get; set; }

            public string SecureKey { get; set; }
        }
    }
}