using System;
using System.Web;

//正则
using System.Text.RegularExpressions;

using System.Security.Cryptography;
//泛型
using System.Collections.Generic;
// 字符相关
using System.Text;

namespace HttpProxyWorld
{
	/**
	 * 生成签名类
	 *
	 * @version 3.0.0
	 * @author open.qq.com
	 * @copyright © 2012, Tencent Corporation. All rights reserved.
	 * @ History:
	 *               3.0.0 | coolinchen | 2013-1-11 11:11:11 | initialization
	 */
	 
    public class SnsSigCheck
    {
        public SnsSigCheck()
        {
        }

        /// <summary>
        ///   生成签名
        /// </summary>
        /// <param name="method">请求方法 get/post </param>
        /// <param name="url_path">url_path</param>
        /// <param name="param">表单参数</param>
        /// <param name="secret">密钥</param>
        /// <returns>返回签名结果</returns>
        //
        static public string MakeSig(string method, string url_path, Dictionary<string, string>param, string secret)
        {
            string mk = MakeSource(method, url_path, param);
            //使用SHA1的HMAC
            HMAC hmac = HMACSHA1.Create();
            hmac.Key = Encoding.UTF8.GetBytes(secret); 
            byte[] hash = hmac.ComputeHash(Encoding.UTF8.GetBytes(mk));
            //转为base64编码
            string my_sign =  Convert.ToBase64String(hash);
            return my_sign;
        }


        static private string MakeSource(string method, string url_path, Dictionary<string, string> param)
        {
            string strs = method.ToUpper() + "&" + UrlEncode(url_path, Encoding.UTF8) + "&";
            string query_string = "";
            List<KeyValuePair<string, string>> myList = new List<KeyValuePair<string, string>>(param);
            myList.Sort(delegate(KeyValuePair<string, string> s1, KeyValuePair<string, string> s2)
            {
                return s1.Key.CompareTo(s2.Key);
            });
            foreach (KeyValuePair<string, string> pair in myList)
            {
                query_string = query_string + pair.Key + "=" + pair.Value + "&";
            }
            query_string = query_string.Substring(0, query_string.Length - 1);
            query_string = UrlEncode(query_string, Encoding.UTF8);
            return  strs + query_string; 
        }


        /// <summary>
        ///解决HttpUtility.UrlEncode会将符号编码为小写英文的问题
        /// </summary>
        /// <param name="temp">待编码的字符串</param>
        /// <param name="encoding">编码的方式</param>
        /// <returns>返回编码结果</returns>
        static public string UrlEncode(string temp, Encoding encoding)
        {
            StringBuilder builder = new StringBuilder();
            for (int i = 0; i < temp.Length; i++)
            {
                string t = temp[i].ToString();
                string k;
                switch (t)
                {
                    case "'":
                        t = "%27";
                        builder.Append(t); 
                        break;

                    case " ":
                        t = "%20";
                        builder.Append(t); 
                        break;

                    case "(":
                        t = "%28";
                        builder.Append(t);
                        break;

                    case ")":
                        t = "%29";
                        builder.Append(t);
                        break;

                    case "!":
                        t = "%21";
                        builder.Append(t);
                        break;

                    case "*":
                        t = "%2A";
                        builder.Append(t);
                        break;

                    default:
                        k = HttpUtility.UrlEncode(t, encoding);
                        if (t == k)
                        {
                            builder.Append(t);
                        }
                        else
                        {
                            builder.Append(k.ToUpper());
                        }
                        break;
                }
            }
            return builder.ToString();
        }

        /// <summary>
        ///验证回调发货URL的签名 (注意和普通的OpenAPI签名算法不一样, 详见
        ///http://wiki.open.qq.com/wiki/%E5%9B%9E%E8%B0%83%E5%8F%91%E8%B4%A7URL%E7%9A%84%E5%8D%8F%E8%AE%AE%E8%AF%B4%E6%98%8E_V3
        /// </summary>
        /// <param name="method">请求方法 get/post</param>
        /// <param name="url_path">url_path</param>
        /// <param name="param">腾讯调用发货回调URL携带的请求参数</param>
        /// <param name="secret">密钥</param>
        /// <param name="sig">腾讯调用发货回调URL时传递的签名</param>
        /// <returns>签名校验结果</returns>

        static public bool VerifySig(string method,string url_path, Dictionary<string, string> param,string secret,string sig) 
        {
            
            // param无需传sig
            if (param.ContainsKey("sig"))
            {
                param.Remove("sig");
            }
            Dictionary<string, string> new_param = new Dictionary<string, string>();

            // 先使用专用的编码规则对value编码
            foreach (string key in param.Keys)
            {
                new_param.Add(key, EncodeValue(param[key]));
            }

            // 再计算签名
            string sig_new = MakeSig(method, url_path, new_param, secret);

            return sig_new.Equals(sig);
        }




        /// <summary>
        ///回调发货URL专用的编码算法
        ///编码规则为：除了 0~9 a~z A~Z !*()之外其他字符按其ASCII码的十六进制加%进行表示，例如"-"编码为"%2D"
        ///详见 http://wiki.open.qq.com/wiki/%E5%9B%9E%E8%B0%83%E5%8F%91%E8%B4%A7URL%E7%9A%84%E5%8D%8F%E8%AE%AE%E8%AF%B4%E6%98%8E_V3
        /// </summary>
        /// <param name="value">待编码的字符串</param>
        /// <returns>返回编码结果</returns>
        static public string  EncodeValue(string value) 
        {
            StringBuilder builder = new StringBuilder();
            for (int i = 0; i < value.Length; i++)
            {
                if (Regex.IsMatch(value[i].ToString(), @"[a-zA-Z0-9!()*]"))
                {
                    builder.Append(value[i].ToString());
                }
                else
                {
                    //byte[] bt = new byte[1];
                    byte[] bt = Encoding.UTF8.GetBytes(value[i].ToString());//中文的话，一个汉字有三个字节
                    for (int k = 0; k < bt.Length; k++)
                    {
                        int ascii = (short)(bt[k]);//计算每个字节的ascii码值
                        builder.Append("%" + Convert.ToString(ascii, 16).ToUpper());
                    }
                    
                }
            }
            return builder.ToString();
        } 


    }
}