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

namespace Bowin.Common.Security
{
    internal class Utils
    {
        /// <summary>
        /// 该方法用来检测用户输入是否带有恶意
        /// </summary>
        /// <param name="text">用户输入的文字</param>
        /// <param name="maxlength">最大的长度</param>
        /// <returns>返回验证后的文字</returns>
        public static string InputText(string text, int maxlength)
        {
            text = text.ToLower().Trim();
            if (text == null || text.Length == 0)
                return string.Empty;
            if (text.Length > maxlength)
                text = text.Substring(0, maxlength);

            text = Regex.Replace(text, "[\\s]{2,{", " ");
            text = Regex.Replace(text, "(<[b|B][r|R]/*>)+|(<[p|P](.|\\n)*?>)", "\n"); //<br>
            text = Regex.Replace(text, "(\\s*&[n|N][b|B][s|S][p|P];\\s*)+", " "); //&nbsp;
            text = Regex.Replace(text, "<(.|\\n)*?>", string.Empty); //any other tags
            text = Regex.Replace(text, "=", "");
            text = Regex.Replace(text, "%", "");
            text = Regex.Replace(text, "'", "");
            text = Regex.Replace(text, "select ", "");
            text = Regex.Replace(text, "insert ", "");
            text = Regex.Replace(text, "delete ", "");
            text = Regex.Replace(text, "or ", "");
            text = Regex.Replace(text, "-- ", "");
            text = Regex.Replace(text, "and ", "");
            text = Regex.Replace(text, "where ", "");
            text = Regex.Replace(text, "update ", "");
            text = Regex.Replace(text, "script ", "");
            text = Regex.Replace(text, "iframe ", "");
            text = Regex.Replace(text, "master ", "");
            text = Regex.Replace(text, "exec ", "");
            text = Regex.Replace(text, "<", "");
            text = Regex.Replace(text, ">", "");
            text = Regex.Replace(text, "\r\n", "");

            return text;
        }

        public static List<string> scriptwords()
        {
            List<string> lw = new List<string>();

            lw.Add("|");
            lw.Add("&");
            lw.Add(";");
            lw.Add("$");
            lw.Add("%");
            lw.Add("@");
            lw.Add(Chr(34));
            lw.Add("\'");
            lw.Add("\\" + Chr(34));
            lw.Add("<");
            lw.Add(">");
            lw.Add("(");
            lw.Add(")");
            lw.Add("+");
            lw.Add(Chr(13));
            lw.Add(Chr(10));
            lw.Add(",");
            lw.Add("\\");

            return lw;
        }

        public static string Chr(int asciiCode)
        {
            if (asciiCode >= 0 && asciiCode <= 255)
            {
                System.Text.ASCIIEncoding asciiEncoding = new System.Text.ASCIIEncoding();
                byte[] byteArray = new byte[] { (byte)asciiCode };
                string strCharacter = asciiEncoding.GetString(byteArray);
                return (strCharacter);
            }
            else
            {
                return "";
            }
        }

        public static List<string> sqlwords()
        {
            List<string> lw = new List<string>();

            lw.Add("select ");
            lw.Add("insert ");
            lw.Add("delete ");
            lw.Add("or ");
            lw.Add("exec ");
            lw.Add("-- ");
            lw.Add("and ");
            lw.Add("where ");
            lw.Add("update ");
            lw.Add("master ");
            lw.Add("script ");
            lw.Add("iframe ");
            lw.Add("declare ");
            lw.Add("char(");
            lw.Add("javascript:");
            lw.Add("truncate ");
            lw.Add("script>");
            lw.Add("/**/");

            return lw;
        }

        /// <summary>
        /// 判断是否包含sql注入关键字
        /// </summary>
        /// <param name="text"></param>
        /// <returns></returns>
        public static bool isSqlWord(string text)
        {
            bool result = false;

            foreach (string w in sqlwords())
            {
                if (text.ToLower().Contains(w))
                {
                    result = true;

                    break;
                }
            }

            return result;
        }

        /// <summary>
        /// 判断是否包含script危险字符
        /// </summary>
        /// <param name="text"></param>
        /// <returns></returns>
        public static bool isscriptword(string text)
        {
            bool result = false;

            foreach (string w in scriptwords())
            {
                if (text.Contains(w))
                {
                    result = true;

                    break;
                }
            }

            return result;
        }
    }
}