using System;

using System.Text;

using System.Text.RegularExpressions;

using System.Net;

using System.IO;

using System.IO.Compression;

namespace HuaTong.General.Utility

{

    /// <summary>

    /// html内容处理

    /// </summary>

    public static class HtmlHelper

    {

        /// <summary>

        /// 纯文本转HTML

        /// </summary>

        public static string TextToHTML(string value)

        {

            return TextToHTML(value, false, false);

        }

        /// <summary>

        /// 纯文本转HTML

        /// </summary>

        public static string TextToHTML(string value, bool isHasEmptyRow)

        {

            return TextToHTML(value, isHasEmptyRow, false);

        }

        /// <summary>

        /// 纯文本转HTML

        /// </summary>

        public static string TextToHTML(string value, bool isHasEmptyRow, bool isOutBr)

        {

            StringBuilder sr = new StringBuilder();

            if (isHasEmptyRow)

            {

                sr.Append(StringHelper.RemoveEmptyRow(value));

            }

            else

            {

                sr.Append(value);

            }

            sr.Replace("&", "&amp;");

            sr.Replace(">", "&gt;");

            sr.Replace("<", "&lt;");

            sr.Replace(" ", "&nbsp;");

            sr.Replace("\"", "&quot;");

            sr.Replace("©", "&copy;");

            sr.Replace("®", "&reg;");

            sr.Replace("×", "&times;");

            sr.Replace("÷", "&divide;");

            if (isOutBr)

            {

                sr.Replace("\r\n", "<br>");

                sr.Replace("\r", "<br>");

                sr.Replace("\n", "<br>");

            }

            else

            {

                sr.Insert(, "<p>");

                sr.Replace("\r\n", "\r");

                sr.Replace("\r", "</p>\r\n<p>");

                sr.Append("</p>");

            }

            return sr.ToString();

        }

        /// <summary>

        /// HTML输出为JS

        /// </summary>

        public static string HtmlToScript(string value)

        {

            StringBuilder sr = new StringBuilder();

            sr.Append(value);

            sr.Replace("\\", "\\\\");

            sr.Replace("/", "\\/");

            sr.Replace("'", "\\'");

            sr.Replace("\"", "\\\"");

            string[] strs = sr.ToString().Split(new char[] { '\r', '\n' },

                StringSplitOptions.RemoveEmptyEntries);

            return String.Format("document.writeln(\"{0}\");",

                String.Join("\");\r\ndocument.writeln(\"", strs),

                StringSplitOptions.RemoveEmptyEntries);

        }

        /// <summary>

        /// JS脚本输出字符串

        /// </summary>

        /// <returns></returns>

        public static string ScriptStringFormat(string value)

        {

            value = value.Replace("\\", "\\\\");

            value = value.Replace("'", "\\'");

            value = value.Replace("\"", "\\\"");

            return value;

        }

        /// <summary>

        /// HTML转纯文本

        /// </summary>

        public static string HtmlToText(string value)

        {

            string regexstr = @"(&(#)?.+;)|(<[^>]*>)";

            return Regex.Replace(value, regexstr, "", RegexOptions.IgnoreCase);

        }

        /// <summary>

        /// 过滤HTML中的不安全标签

        /// </summary>

        public static string HtmlFilter(string value)

        {

            value = Regex.Replace(value, @"(\<|\s+)o([a-z]+\s?=)", "$1$2", RegexOptions.IgnoreCase);

            value = Regex.Replace(value, @"(select|textarea|input|link|iframe|frameset|frame|form|applet|embedlayer|ilayer|meta|object|script|behavior|style)([\s|:|>])+", "$1.$2", RegexOptions.IgnoreCase);

            value = Regex.Replace(value, @"javascript|eval", "", RegexOptions.IgnoreCase);

            return value;

        }

        /// <summary>

        /// 获取源代码

        /// </summary>

        public static string GetHtmlContent(string url, string encoding)

        {

            HttpWebRequest request = null;

            HttpWebResponse response = null;

            StreamReader reader = null;

            try

            {

                request = (HttpWebRequest)WebRequest.Create(url);

                request.Timeout = ;

                request.AllowAutoRedirect = false;

                response = (HttpWebResponse)request.GetResponse();

                if (response.StatusCode == HttpStatusCode.OK)

                {

                    if (response.ContentEncoding != null && StringHelper.IsEqualString(response.ContentEncoding,"gzip"))

                        reader = new StreamReader(new GZipStream(response.GetResponseStream(), CompressionMode.Decompress), Encoding.GetEncoding(encoding));

                    else

                        reader = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding(encoding));

                    string html = reader.ReadToEnd();

                    return html;

                }

            }

            catch

            {

            }

            finally

            {

                if (response != null)

                {

                    response.Close();

                    response = null;

                }

                if (reader != null)

                    reader.Close();

                if (request != null)

                    request = null;

            }

            return string.Empty;

        }

        /// <summary>

        /// 获取HTML网页的编码

        /// </summary>

        /// <returns></returns>

        public static string GetEncoding(string url)

        {

            string charset = string.Empty;

            HttpWebRequest request = null;

            HttpWebResponse response = null;

            StreamReader reader = null;

            try

            {

                request = (HttpWebRequest)WebRequest.Create(url);

                request.Timeout = ;

                request.AllowAutoRedirect = false;

                response = (HttpWebResponse)request.GetResponse();

                if (response.StatusCode == HttpStatusCode.OK && response.ContentLength <  * )

                {

                    if (response.ContentEncoding != null && StringHelper.IsEqualString(response.ContentEncoding, "gzip"))

                        reader = new StreamReader(new GZipStream(response.GetResponseStream(), CompressionMode.Decompress));

                    else

                        reader = new StreamReader(response.GetResponseStream(), Encoding.ASCII);

                    string html = reader.ReadToEnd();

                    Regex reg_charset = new Regex(@"charset\b\s*=\s*(?<charset>[^""]*)");

                    if (reg_charset.IsMatch(html))

                    {

                        return reg_charset.Match(html).Groups["charset"].Value;

                    }

                    else if (response.CharacterSet != string.Empty)

                    {

                        return response.CharacterSet;

                    }

                    else

                        return Encoding.Default.BodyName;

                }

            }

            catch

            {

            }

            finally

            {

                if (response != null)

                {

                    response.Close();

                    response = null;

                }

                if (reader != null)

                    reader.Close();

                if (request != null)

                    request = null;

            }

            return Encoding.Default.BodyName;

        }

    }

}