/// <summary>
/// 輸入產(chǎn)數(shù)
/// </summary>
class InputQuery
{
    /// <summary>
    /// APP ID
    /// </summary>
    private static string appId = "2021xxxxxxx0626";
    /// <summary>
    /// 密鑰
    /// </summary>
    private static string passWord = "cnblongsxtimefiles";


    /// <summary>
    /// 請(qǐng)求翻譯query UTF-8編碼
    /// </summary>
    public string Content { get; set; }
    /// <summary>
    /// 翻譯源語(yǔ)言 可設(shè)置為auto
    /// </summary>
    public string From { get; set; }
    /// <summary>
    /// 翻譯目標(biāo)語(yǔ)言 不可設(shè)置為auto
    /// </summary>
    public string To { get; set; }
    /// <summary>
    /// APP ID
    /// </summary>
    public string AppId { get; set; }
    /// <summary>
    /// 隨機(jī)數(shù) 可為字母或數(shù)字的字符串
    /// </summary>
    public string Salt { get; set; }
    /// <summary>
    /// 簽名 appid+q+salt+密鑰的MD5值
    /// </summary>
    public string Sign { get; set; }

    /// <summary>
    /// 構(gòu)造函數(shù)
    /// </summary>
    /// <param name="content">翻譯內(nèi)容</param>
    /// <param name="fromStr">源語(yǔ)言</param>
    /// <param name="toStr">目標(biāo)語(yǔ)言</param>
    public InputQuery(string content, string fromStr, string toStr)
    {
        Content = content;
        From = fromStr;
        To = toStr;
        AppId = appId;

        string randomNum = new Random().Next().ToString();
        string md5Sign = GetMD5(appId + content + randomNum + passWord).ToLower();
        Salt = randomNum;
        Sign = md5Sign;
    }

    /// <summary>
    /// 計(jì)算字符串的MD5值
    /// </summary>
    static string GetMD5(string source)
    {
        MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
        byte[] data = Encoding.UTF8.GetBytes(source);
        byte[] md5Data = md5.ComputeHash(data, 0, data.Length);
        md5.Clear();

        string destString = string.Empty;
        for (int i = 0; i < md5Data.Length; i++)
        {
            destString += Convert.ToString(md5Data[i], 16).PadLeft(2, '0');
        }
        destString = destString.PadLeft(32, '0');
        return destString;
    }
}

/// <summary>
/// 輸出參數(shù)
/// </summary>
[DataContract]
class OutputResult
{
    
    /// <summary>
    /// 錯(cuò)誤碼 僅當(dāng)出現(xiàn)錯(cuò)誤時(shí)顯示
    /// </summary>
    [DataMember(Name = "error_code")]
    public string Error_code { set; get; }

    /// <summary>
    /// 錯(cuò)誤信息
    /// </summary>
    [DataMember(Name = "error_msg")]
    public string Error_msg { set; get; }

    /// <summary>
    /// 源語(yǔ)言 返回用戶指定的語(yǔ)言，或者自動(dòng)檢測(cè)出的語(yǔ)種（源語(yǔ)言設(shè)為 auto 時(shí)）
    /// </summary>
    [DataMember(Name = "from")]
    public string From { set; get; }

    /// <summary>
    /// 目標(biāo)語(yǔ)言 返回用戶指定的目標(biāo)語(yǔ)言
    /// </summary>
    [DataMember(Name = "to")]
    public string To { set; get; }

    /// <summary>
    /// 翻譯結(jié)果 返回翻譯結(jié)果，包括 src 和 dst 字段
    /// </summary>
    [DataMember(Name = "trans_result")]
    public TranslateContent[] Trans_result { set; get; }
}
/// <summary>
/// 翻譯結(jié)果
/// </summary>
[DataContract]
class TranslateContent
{
    /// <summary>
    /// 原文
    /// </summary>
    [DataMember(Name = "src")]
    public string Src { set; get; }

    /// <summary>
    /// 譯文
    /// </summary>
    [DataMember(Name = "dst")]
    public string Dst { set; get; }
}

public class GoodController
{
    public static readonly HttpClient HttpClient;

    static GoodController()
    {
        HttpClient = new HttpClient();
    }
}

/// <summary>
/// 百度通用翻譯API工具類
/// </summary>
class Translate
{
    /*
     * 代碼鏈接：https://www.cnblogs.com/timefiles/p/BaiduTranslateAPI.html
     * 創(chuàng)建時(shí)間：2021/06/26
     * 主頁(yè)鏈接：https://www.cnblogs.com/timefiles/
     * 
     * 常用的語(yǔ)種代碼：
     * 自動(dòng)檢測(cè)	auto	
     * 中文	zh	
     * 英語(yǔ)	en
     * 日語(yǔ)	jp
     */

    /// <summary>
    /// 英文翻譯為中文
    /// </summary>
    /// <param name="content">翻譯內(nèi)容</param>
    /// <returns></returns>
    public static string EnToZh(string content)
    {
        string languageFrom = "en", languageTo = "zh";
        return GetTranslateResult(content, languageFrom, languageTo);
    }

    /// <summary>
    /// 獲取翻譯結(jié)果
    /// </summary>
    /// <param name="content">翻譯內(nèi)容</param>
    /// <param name="fromStr">源語(yǔ)言</param>
    /// <param name="toStr">目標(biāo)語(yǔ)言</param>
    /// <returns></returns>
    static string GetTranslateResult(string content, string fromStr, string toStr)
    {
        InputQuery input = new InputQuery(content, fromStr, toStr);
        Uri uri = GetUri(input);
        var task = GetOutputResultAsync(uri);
        //個(gè)人認(rèn)證后API的每秒請(qǐng)求量最高為10，異步意義不大，直接使用同步的方式
        OutputResult output = task.Result;
        if (output.Error_code == null)
        {
            return output.Trans_result[0].Dst;
        }
        else
        {
            throw new Exception("翻譯異常，錯(cuò)誤代碼：" + output.Error_msg);
        }
    }

    /// <summary>
    /// 獲取請(qǐng)求Uri
    /// </summary>
    /// <param name="input"></param>
    /// <returns></returns>
    static Uri GetUri(InputQuery input)
    {
        var query = HttpUtility.ParseQueryString(string.Empty);
        query["q"] = input.Content;
        query["from"] = input.From;
        query["to"] = input.To;
        query["appid"] = input.AppId;
        query["salt"] = input.Salt;
        query["sign"] = input.Sign;

        //構(gòu)造Uri，不建議直接拼字符串
        UriBuilder uriBur = new UriBuilder("http://api.fanyi.baidu.com/api/trans/vip/translate");
        uriBur.Query = query.ToString();
        //Uri會(huì)自動(dòng)進(jìn)行轉(zhuǎn)義
        return uriBur.Uri;
    }

    /// <summary>
    /// 獲取API返回的結(jié)果
    /// </summary>
    /// <param name="uri">請(qǐng)求的uri</param>
    /// <returns></returns>
    static async Task<OutputResult> GetOutputResultAsync(Uri uri)
    {
        OutputResult result = null;
        var response = await GoodController.HttpClient.GetStringAsync(uri);
        var ser = new DataContractJsonSerializer(typeof(OutputResult));
        using (var ms = new MemoryStream(Encoding.UTF8.GetBytes(response)))
        {
            result = (OutputResult)ser.ReadObject(ms);
        }
        return result;
    }
}

static void Main(string[] args)
{
    XmlDocument xd = new XmlDocument();
    xd.Load("index_examples_en_US.xml");
    //查找固定名稱 節(jié)點(diǎn)名要從根節(jié)點(diǎn)開始寫
    XmlNodeList nodelist = xd.DocumentElement.SelectNodes("/examples/example/desc");
    for (int i = 0; i < nodelist.Count; i++)
    {
        string desc = nodelist[i].InnerText;
        //百度翻譯有時(shí)不太準(zhǔn)確，建議保留原文
        nodelist[i].InnerText = Translate.EnToZh(desc)+"（"+ nodelist[i].InnerText+"）";               
        Console.WriteLine("翻譯結(jié)果"+i+"：" + nodelist[i].InnerText);
        Console.WriteLine();
    }

    StreamWriter sw = new StreamWriter("index_examples_en_US_翻譯.xml", false, new UTF8Encoding(false));
    //為了和原文件保存一致，原文件是使用的是"\n"換行
    sw.NewLine = "\n";
    xd.Save(sw);
    sw.Close();                  
    Console.WriteLine("完成");
    Console.Read();
}