using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.Text;

namespace POSV.Utils
{
    /// <summary>
    /// HTTP 请求工具类
    /// </summary>
    public static class RequestUtility
    {
        #region 代理

        private static WebProxy _webproxy = null;

        /// <summary>
        /// 设置Web代理
        /// </summary>
        /// <param name="host"></param>
        /// <param name="port"></param>
        /// <param name="username"></param>
        /// <param name="password"></param>
        public static void SetHttpProxy(string host , string port , string username , string password)
        {
            ICredentials cred;
            cred = new NetworkCredential(username , password);
            if (!string.IsNullOrEmpty(host))
            {
                _webproxy = new WebProxy(host + ":" + port ?? "80" , true , null , cred);
            }
        }

        /// <summary>
        /// 清除Web代理状态
        /// </summary>
        public static void RemoveHttpProxy()
        {
            _webproxy = null;
        }

        #endregion

        #region 同步方法

        #region Get

        /// <summary>
        /// 使用Get方法获取字符串结果（没有加入Cookie）
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public static string HttpGet(string url , Encoding encoding = null)
        {
            WebClient wc = new WebClient();
            wc.Proxy = _webproxy;
            wc.Encoding = encoding ?? Encoding.UTF8;
            return wc.DownloadString(url);
        }

        /// <summary>
        /// 使用Get方法获取字符串结果（加入Cookie）
        /// </summary>
        /// <param name="url"></param>
        /// <param name="cookieContainer"></param>
        /// <param name="encoding"></param>
        /// <param name="cer">证书，如果不需要则保留null</param>
        /// <param name="timeOut"></param>
        /// <returns></returns>
        public static string HttpGet(string url , CookieContainer cookieContainer = null , Encoding encoding = null , X509Certificate2 cer = null , int timeOut = Constant.TIMEOUT)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "GET";
            request.Timeout = timeOut;
            request.Proxy = _webproxy;
            if (cer != null)
            {
                request.ClientCertificates.Add(cer);
            }

            if (cookieContainer != null)
            {
                request.CookieContainer = cookieContainer;
            }

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();

            if (cookieContainer != null)
            {
                response.Cookies = cookieContainer.GetCookies(response.ResponseUri);
            }

            using (Stream responseStream = response.GetResponseStream())
            {
                using (StreamReader myStreamReader = new StreamReader(responseStream , encoding ?? Encoding.GetEncoding("utf-8")))
                {
                    string retString = myStreamReader.ReadToEnd();
                    return retString;
                }
            }
        }

        #endregion

        #region Post

        /// <summary>
        /// 使用Post方法获取字符串结果，常规提交
        /// </summary>
        /// <returns></returns>
        public static string HttpPost(string url , CookieContainer cookieContainer = null , Dictionary<string , string> formData = null , Encoding encoding = null , X509Certificate2 cer = null , int timeOut = Constant.TIMEOUT)
        {
            MemoryStream ms = new MemoryStream();
            formData.FillFormDataStream(ms);//填充formData
            return HttpPost(url , cookieContainer , ms , null , null , encoding , cer , timeOut);
        }

        /// <summary>
        /// 使用Post方法获取字符串结果
        /// </summary>
        /// <param name="url"></param>
        /// <param name="cookieContainer"></param>
        /// <param name="postStream"></param>
        /// <param name="fileDictionary">需要上传的文件，Key：对应要上传的Name，Value：本地文件名</param>
        /// <param name="encoding"></param>
        /// <param name="cer">证书，如果不需要则保留null</param>
        /// <param name="timeOut"></param>
        /// <param name="checkValidationResult">验证服务器证书回调自动验证</param>
        /// <param name="refererUrl"></param>
        /// <returns></returns>
        public static string HttpPost(string url , CookieContainer cookieContainer = null , Stream postStream = null , Dictionary<string , string> fileDictionary = null , string refererUrl = null , Encoding encoding = null , X509Certificate2 cer = null , int timeOut = Constant.TIMEOUT , bool checkValidationResult = false)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "POST";
            request.Timeout = timeOut;
            request.Proxy = _webproxy;
            if (cer != null)
            {
                request.ClientCertificates.Add(cer);
            }

            if (checkValidationResult)
            {
                ServicePointManager.ServerCertificateValidationCallback =
                    new RemoteCertificateValidationCallback(CheckValidationResult);
            }

            #region 处理Form表单文件上传
            var formUploadFile = fileDictionary != null && fileDictionary.Count > 0;//是否用Form上传文件
            if (formUploadFile)
            {
                //通过表单上传文件
                postStream = postStream ?? new MemoryStream();

                string boundary = "----" + DateTime.Now.Ticks.ToString("x");
                //byte[] boundarybytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
                string fileFormdataTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: application/octet-stream\r\n\r\n";
                string dataFormdataTemplate = "\r\n--" + boundary +
                                                "\r\nContent-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
                foreach (var file in fileDictionary)
                {
                    try
                    {
                        var fileName = file.Value;
                        //准备文件流
                        using (var fileStream = FileHelper.GetFileStream(fileName))
                        {
                            string formdata = null;
                            if (fileStream != null)
                            {
                                //存在文件
                                formdata = string.Format(fileFormdataTemplate , file.Key , /*fileName*/ Path.GetFileName(fileName));
                            }
                            else
                            {
                                //不存在文件或只是注释
                                formdata = string.Format(dataFormdataTemplate , file.Key , file.Value);
                            }

                            //统一处理
                            var formdataBytes = Encoding.UTF8.GetBytes(postStream.Length == 0 ? formdata.Substring(2 , formdata.Length - 2) : formdata);//第一行不需要换行
                            postStream.Write(formdataBytes , 0 , formdataBytes.Length);

                            //写入文件
                            if (fileStream != null)
                            {
                                byte[] buffer = new byte[1024];
                                int bytesRead = 0;
                                while ((bytesRead = fileStream.Read(buffer , 0 , buffer.Length)) != 0)
                                {
                                    postStream.Write(buffer , 0 , bytesRead);
                                }
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        throw ex;
                    }
                }
                //结尾
                var footer = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");
                postStream.Write(footer , 0 , footer.Length);

                request.ContentType = string.Format("multipart/form-data; boundary={0}" , boundary);
            }
            else
            {
                request.ContentType = "application/x-www-form-urlencoded";
            }
            #endregion

            request.ContentLength = postStream != null ? postStream.Length : 0;
            request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
            request.KeepAlive = true;

            if (!string.IsNullOrEmpty(refererUrl))
            {
                request.Referer = refererUrl;
            }
            request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.57 Safari/537.36";

            if (cookieContainer != null)
            {
                request.CookieContainer = cookieContainer;
            }

            #region 输入二进制流
            if (postStream != null)
            {
                postStream.Position = 0;

                //直接写入流
                Stream requestStream = request.GetRequestStream();

                byte[] buffer = new byte[1024];
                int bytesRead = 0;
                while ((bytesRead = postStream.Read(buffer , 0 , buffer.Length)) != 0)
                {
                    requestStream.Write(buffer , 0 , bytesRead);
                }

                //debug
                //postStream.Seek(0, SeekOrigin.Begin);
                //StreamReader sr = new StreamReader(postStream);
                //var postStr = sr.ReadToEnd();

                postStream.Close();//关闭文件访问
            }
            #endregion

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();

            if (cookieContainer != null)
            {
                response.Cookies = cookieContainer.GetCookies(response.ResponseUri);
            }

            using (Stream responseStream = response.GetResponseStream())
            {
                using (StreamReader myStreamReader = new StreamReader(responseStream , encoding ?? Encoding.GetEncoding("utf-8")))
                {
                    string retString = myStreamReader.ReadToEnd();
                    return retString;
                }
            }
        }

        /// <summary>
        /// 使用Post方法获取字符串结果
        /// </summary>
        /// <param name="url"></param>
        /// <param name="cookieContainer"></param>
        /// <param name="postStream"></param>
        /// <param name="fileDictionary">需要上传的文件，Key：对应要上传的Name，Value：本地文件名</param>
        /// <param name="encoding"></param>
        /// <param name="cer">证书，如果不需要则保留null</param>
        /// <param name="timeOut"></param>
        /// <param name="checkValidationResult">验证服务器证书回调自动验证</param>
        /// <param name="refererUrl"></param>
        /// <returns></returns>
        public static string HttpPostCCB(string url, CookieContainer cookieContainer = null, Stream postStream = null, Dictionary<string, string> fileDictionary = null, string refererUrl = null, Encoding encoding = null, X509Certificate2 cer = null, int timeOut = Constant.TIMEOUT, bool checkValidationResult = false)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "POST";
            request.Timeout = timeOut;
            request.Proxy = _webproxy;
            if (cer != null)
            {
                request.ClientCertificates.Add(cer);
            }

            if (checkValidationResult)
            {
                ServicePointManager.ServerCertificateValidationCallback =
                    new RemoteCertificateValidationCallback(CheckValidationResult);
            }

            #region 处理Form表单文件上传
            var formUploadFile = fileDictionary != null && fileDictionary.Count > 0;//是否用Form上传文件
            if (formUploadFile)
            {
                //通过表单上传文件
                postStream = postStream ?? new MemoryStream();

                string boundary = "----" + DateTime.Now.Ticks.ToString("x");
                //byte[] boundarybytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
                string fileFormdataTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: application/octet-stream\r\n\r\n";
                string dataFormdataTemplate = "\r\n--" + boundary +
                                                "\r\nContent-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
                foreach (var file in fileDictionary)
                {
                    try
                    {
                        var fileName = file.Value;
                        //准备文件流
                        using (var fileStream = FileHelper.GetFileStream(fileName))
                        {
                            string formdata = null;
                            if (fileStream != null)
                            {
                                //存在文件
                                formdata = string.Format(fileFormdataTemplate, file.Key, /*fileName*/ Path.GetFileName(fileName));
                            }
                            else
                            {
                                //不存在文件或只是注释
                                formdata = string.Format(dataFormdataTemplate, file.Key, file.Value);
                            }

                            //统一处理
                            var formdataBytes = Encoding.UTF8.GetBytes(postStream.Length == 0 ? formdata.Substring(2, formdata.Length - 2) : formdata);//第一行不需要换行
                            postStream.Write(formdataBytes, 0, formdataBytes.Length);

                            //写入文件
                            if (fileStream != null)
                            {
                                byte[] buffer = new byte[1024];
                                int bytesRead = 0;
                                while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
                                {
                                    postStream.Write(buffer, 0, bytesRead);
                                }
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        throw ex;
                    }
                }
                //结尾
                var footer = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");
                postStream.Write(footer, 0, footer.Length);

                request.ContentType = string.Format("multipart/form-data; boundary={0}", boundary);
            }
            else
            {
                request.ContentType = "application/x-www-form-urlencoded";
            }
            #endregion

            request.ContentLength = postStream != null ? postStream.Length : 0;
            request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
            request.KeepAlive = false;
            request.ProtocolVersion = new Version(1, 0);

            if (!string.IsNullOrEmpty(refererUrl))
            {
                request.Referer = refererUrl;
            }
            request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.57 Safari/537.36";

            if (cookieContainer != null)
            {
                request.CookieContainer = cookieContainer;
            }

            #region 输入二进制流
            if (postStream != null)
            {
                postStream.Position = 0;

                //直接写入流
                Stream requestStream = request.GetRequestStream();

                byte[] buffer = new byte[1024];
                int bytesRead = 0;
                while ((bytesRead = postStream.Read(buffer, 0, buffer.Length)) != 0)
                {
                    requestStream.Write(buffer, 0, bytesRead);
                }

                //debug
                //postStream.Seek(0, SeekOrigin.Begin);
                //StreamReader sr = new StreamReader(postStream);
                //var postStr = sr.ReadToEnd();

                postStream.Close();//关闭文件访问
            }
            #endregion

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();

            if (cookieContainer != null)
            {
                response.Cookies = cookieContainer.GetCookies(response.ResponseUri);
            }

            using (Stream responseStream = response.GetResponseStream())
            {
                using (StreamReader myStreamReader = new StreamReader(responseStream, encoding ?? Encoding.GetEncoding("GB18030")))
                {
                    string retString = myStreamReader.ReadToEnd();
                    return retString;
                }
            }
        }


        #endregion

        /// <summary>
        /// 验证服务器证书
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="certificate"></param>
        /// <param name="chain"></param>
        /// <param name="errors"></param>
        /// <returns></returns>
        private static bool CheckValidationResult(object sender , X509Certificate certificate , X509Chain chain , SslPolicyErrors errors)
        {
            return true;
        }


        #endregion

        /// <summary>
        /// 组装QueryString的方法
        /// 参数之间用&amp;连接，首位没有符号，如：a=1&amp;b=2&amp;c=3
        /// </summary>
        /// <param name="formData"></param>
        /// <returns></returns>
        public static string GetQueryString(this Dictionary<string , string> formData)
        {
            if (formData == null || formData.Count == 0)
            {
                return "";
            }

            StringBuilder sb = new StringBuilder();

            var i = 0;
            foreach (var kv in formData)
            {
                i++;
                sb.AppendFormat("{0}={1}" , kv.Key , kv.Value);
                if (i < formData.Count)
                {
                    sb.Append("&");
                }
            }

            return sb.ToString();
        }

        /// <summary>
        /// 填充表单信息的Stream
        /// </summary>
        /// <param name="formData"></param>
        /// <param name="stream"></param>
        public static void FillFormDataStream(this Dictionary<string , string> formData , Stream stream)
        {
            string dataString = GetQueryString(formData);
            var formDataBytes = formData == null ? new byte[0] : Encoding.UTF8.GetBytes(dataString);
            stream.Write(formDataBytes , 0 , formDataBytes.Length);
            stream.Seek(0 , SeekOrigin.Begin);//设置指针读取位置
        }

        /// <summary>
        /// <para>将 URL 中的参数名称/值编码为合法的格式。</para>
        /// <para>可以解决类似这样的问题：假设参数名为 tvshow, 参数值为 Tom&Jerry，如果不编码，可能得到的网址： http://a.com/?tvshow=Tom&Jerry&year=1965 编码后则为：http://a.com/?tvshow=Tom%26Jerry&year=1965 </para>
        /// <para>实践中经常导致问题的字符有：'&', '?', '=' 等</para>
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public static string AsUrlData(this string data)
        {
            if (data == null)
            {
                return null;
            }
            return Uri.EscapeDataString(data);
        }
    }
}