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

namespace Bowin.Common.Utility
{
    public static class StringEx
    {
        /// <summary>
        /// 从左边起截取指定长度的字符串
        /// </summary>
        /// <param name="input"></param>
        /// <param name="length"></param>
        /// <returns></returns>
        public static string Left(this string input, int length)
        {
            if (input.IsEmpty())
            {
                return string.Empty;
            }

            if (input.Length > length)
            {
                return input.Substring(0, length);
            }

            return input;
        }

        /// <summary>
        /// 从左边起截取指定长度的字符串，并追加指定的字符串
        /// </summary>
        /// <param name="input"></param>
        /// <param name="length"></param>
        /// <returns></returns>
        public static string Left(this string input, int length, string plus)
        {
            if (input.IsEmpty())
            {
                return string.Empty;
            }

            if (input.Length <= length)
            {
                return input;
            }

            return string.Format("{0}{1}", Left(input, length - 1), plus);
        }

        /// <summary>
        /// 验证字符串是否为null 空或者由空白字符串组成
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static bool IsEmpty(this string input)
        {
            if (input == null || input.Trim().Length == 0)
            {
                return true;
            }

            return false;
        }

        /// <summary>
        /// 验证字符串不为null 空或者由空白字符串组成
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static bool IsNotEmpty(this string input)
        {
            return !input.IsEmpty();
        }

        public static string MD5(this string input)
        {
            return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(input, "md5");
        }

        public static string ToCamel(this string input)
        {
            if (input.Length == 0)
            {
                return "";
            }
            else
            {
                string firstCode = input.Substring(0, 1).ToLower();

                return firstCode + input.Substring(1, input.Length - 1);
            }
        }

        public static string TrimStart(this string input, string partern)
        {
            if (input.StartsWith(partern))
            {
                return input.Substring(partern.Length);
            }
            else
            {
                return input;
            }
        }

        public static string TrimEnd(this string input, string partern)
        {
            if (input.EndsWith(partern))
            {
                return input.Remove(input.LastIndexOf(partern));
            }
            else
            {
                return input;
            }
        }

        public static string NoHTML(this string Htmlstring)
        {
            //删除脚本 
            Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?>.*?</script>", "", RegexOptions.IgnoreCase);

            //删除HTML 
            Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"([\r\n])[\s]+", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"-->", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(quot|#34);", "\"", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(amp|#38);", "&", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(nbsp|#160);", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(iexcl|#161);", "\xa1", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(cent|#162);", "\xa2", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(pound|#163);", "\xa3", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(copy|#169);", "\xa9", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&#(\d+);", "", RegexOptions.IgnoreCase);
            //替换单引号 避免js脚本错误 最新文章列表摘要就出错过 duanqh 2011-09-22
            Htmlstring = Htmlstring.Replace("'", "&acute");
            Htmlstring = Htmlstring.Replace("<", "&lt");
            Htmlstring = Htmlstring.Replace(">", "&gt");
            Htmlstring = Htmlstring.Replace("\r\n", "");
            Htmlstring = Htmlstring.Trim();

            return Htmlstring;
        }

        public static string RealTrim(this string source)
        {
            string result = source;

            result = result.Replace("\0", "");
            result = result.Trim();

            return result;
        }

        public static List<Guid?> SplitIDString(this string source, char seperator = ',')
        {
            return source.Split(seperator).Where(x => x != "").Select(x => (Guid?)new Guid(x)).ToList();
        }
    }
}