using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

namespace NetLibrary
{
    public class DataConvert
    {
        public static DateTime? ToDateTime(string value)
        {
            if (value == null || value == "") return null;
            DateTime? dt = null;
            try { dt = Convert.ToDateTime(value); }
            catch { return null; }
            return dt;
        }
        public static Int32? ToInt32(string value)
        {
            if (value == null || value == "") return null;
            Int32? dt = null;
            try { dt = Convert.ToInt32(value); }
            catch { return null; }
            return dt;
        }
        public static Decimal? ToDecimal(string value)
        {
            if (value == null || value == "") return null;
            Decimal? dt = null;
            try { dt = Convert.ToDecimal(value); }
            catch { return null; }
            return dt;
        }
        public static Double? ToDouble(string value)
        {
            if (value == null || value == "") return null;
            Double? dt = null;
            try { dt = Convert.ToDouble(value); }
            catch { return null; }
            return dt;
        }
        public static Single? ToSingle(string value)
        {
            if (value == null || value == "") return null;
            Single? dt = null;
            try { dt = Convert.ToSingle(value); }
            catch { return null; }
            return dt;
        }
        public static Int16? ToInt16(string value)
        {
            if (value == null || value == "") return null;
            Int16? dt = null;
            try { dt = Convert.ToInt16(value); }
            catch { return null; }
            return dt;
        }
        public static String ToString(string value)
        {
            if (value == null || value == "") return "";
            return value.Trim();
        }

        #region 过滤网页标签
        public static String CleanHTMLTag(string htmlStream)
        {
            if (!string.IsNullOrEmpty(htmlStream))
            {
                /*
                 * 最好把所有的特殊HTML标记都找出来，然后把与其相对应的Unicode字符一起影射到Hash表内，最后一起都替换掉
                 */

                //先单独测试,成功后,再把所有模式合并

                //注:这两个必须单独处理
                //去掉嵌套了HTML标记的JavaScript:(<script)[\\s\\S]*(</script>)
                //去掉css标记:(<style)[\\s\\S]*(</style>)
                //去掉css标记:\\..*\\{[\\s\\S]*\\}
                htmlStream = Regex.Replace(htmlStream, "(<script)[\\s\\S]*?(</script>)|(<style)[\\s\\S]*?(</style>)", " ", RegexOptions.IgnoreCase);
                //htmlStream = RemoveTag(htmlStream, "script");
                //htmlStream = RemoveTag(htmlStream, "style");

                //去掉普通HTML标记:<[^>]+>
                //替换空格:&nbsp;|&amp;|&shy;|&#160;|&#173;
                htmlStream = Regex.Replace(htmlStream, "<[^>]+>|&nbsp;|&amp;|&shy;|&#160;|&#173;|&bull;|&lt;|&gt;", " ", RegexOptions.IgnoreCase);
                //htmlStream = RemoveTag(htmlStream);

                //替换左尖括号
                //htmlStream = Regex.Replace(htmlStream, "&lt;", "<");

                //替换右尖括号
                //htmlStream = Regex.Replace(htmlStream, "&gt;", ">");

                //替换空行
                //htmlStream = Regex.Replace(htmlStream, "[\n|\r|\t]", " ");//[\n|\r][\t*| *]*[\n|\r]
                htmlStream = Regex.Replace(htmlStream, "(\r\n[\r|\n|\t| ]*\r\n)|(\n[\r|\n|\t| ]*\n)", "\r\n");
                htmlStream = Regex.Replace(htmlStream, "[\t| ]{1,}", " ");
            }
            return htmlStream.Trim();
        }
        #endregion

        #region 过滤网页代码
        public static String ToCodeString(string value)
        {
            if (value == null || value == "") return "";
            Dictionary<string, string> where = new Dictionary<string, string>();
            where.Add(@"<P .+?>", "");
            where.Add(@"<P>", "");
            where.Add(@"</P>", "");
            where.Add(@"<SPAN .+?>", "");
            where.Add(@"<SPAN>", "");
            where.Add(@"</SPAN>", "");
            where.Add(@"<STRONG>", "");
            where.Add(@"</STRONG>", "");
            where.Add(@"<U>", "");
            where.Add(@"</U>", "");
            where.Add(@"<EM>", "");
            where.Add(@"</EM>", "");
            where.Add(@"<o:p>", "");
            where.Add(@"</o:p>", "");
            where.Add(@"<FONT .+?>", "");
            where.Add(@"</FONT>", "");
            where.Add(@"<I .+?>", "");
            where.Add(@"</I>", "");
            where.Add(@"<B .+?>", "");
            where.Add(@"</B>", "");
            where.Add(@"<.xml:namespace .+?>", "");
            where.Add(@"<st1:chmetcnv .+?>", "");
            where.Add(@"</st1:chmetcnv>", "");
            where.Add(@"\r", "");
            where.Add(@"\n", "");
            where.Add(@"\t", "");
            where.Add(@"&nbsp;", " ");
            where.Add(@"&lt;", "<");
            where.Add(@"&gt;", ">");
            foreach (string s in where.Keys)
            {
                value = Regex.Replace(value, s, where[s], RegexOptions.IgnoreCase);
            }
            return value;
        }
        #endregion

        /// <summary>
        /// 转换空值
        /// </summary>
        /// <param name="value">校验值</param>
        /// <param name="defaultValue">如果是空值，那么用这个值替换</param>
        /// <returns></returns>
        public static object IsNull(object value, object defaultValue)
        {
            if (value != null && value != DBNull.Value) { return value; }
            else { return defaultValue; }
        }

        public static string Format(object value, TypeCode type, string format)
        {
            if (value == null || value.ToString() == "" || value == DBNull.Value) return "";
            if (format == null || format == "") return value.ToString();
            switch (type)
            {
                case TypeCode.DateTime:
                    return Convert.ToDateTime(value).ToString(format);
                case TypeCode.Decimal:
                    return Convert.ToDecimal(value).ToString(format);
                case TypeCode.Double:
                    return Convert.ToDouble(value).ToString(format);
                case TypeCode.Single:
                    return Convert.ToSingle(value).ToString(format);
                default:
                    return "";
            }
        }

        public static string Format(object value, string format)
        {
            if (value == null || value.ToString() == "" || value == DBNull.Value) return "";
            if (format == null || format == "") return value.ToString();
            try
            {
                return Convert.ToDecimal(value).ToString(format);
            }
            catch
            { }
            try
            {
                return Convert.ToDateTime(value).ToString(format);
            }
            catch
            { }
            return value.ToString();
        }

    }
}