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

namespace AppletMvcService.Common
{
    public class RequestHelper
    {
        private static readonly string DefaultUserAgent = "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0";

        /// <summary>  
        /// 创建GET方式的HTTP请求  
        /// </summary>  
        /// <param name="url">请求的URL</param>  
        /// <param name="timeout">请求的超时时间</param>  
        /// <param name="userAgent">请求的客户端浏览器信息，可以为空</param>  
        /// <param name="cookies">随同HTTP请求发送的Cookie信息，如果不需要身份验证可以为空</param>  
        /// <returns></returns>  
        public static HttpWebResponse CreateGetHttpResponse(string url, int? timeout, string userAgent, CookieCollection cookies)
        {
            if (string.IsNullOrEmpty(url))
            {
                return null;
            }
            HttpWebRequest request = null;
            HttpWebResponse response = null;
            try
            {
                ServicePointManager.ServerCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback(CheckValidationResult);//验证服务器证书回调自动验证
                request = WebRequest.Create(url) as HttpWebRequest;
                request.Method = "GET";
                request.UserAgent = DefaultUserAgent;
                if (!string.IsNullOrEmpty(userAgent))
                {
                    request.UserAgent = userAgent;
                }
                if (timeout.HasValue)
                {
                    request.Timeout = timeout.Value;
                }
                if (cookies != null)
                {
                    request.CookieContainer = new CookieContainer();
                    request.CookieContainer.Add(cookies);
                }
                response = request.GetResponse() as HttpWebResponse;
                return response;
            }
            catch (Exception ex)
            {
                if (response != null)
                {
                    response.Close();
                }
                throw (ex);
            }
        }

        public static string CreateGetString(string url, int? timeout, string userAgent, CookieCollection cookies)
        {
            HttpWebResponse response = null;
            Stream stream = null;
            StreamReader sr = null;
            try
            {
                response = CreateGetHttpResponse(url, timeout, userAgent, cookies);
                if (response == null)
                {
                    return string.Empty;
                }
                stream = response.GetResponseStream();
                sr = new StreamReader(stream);
                string strResult = sr.ReadToEnd();
                sr.Close();
                stream.Close();
                response.Close();
                return strResult;
            }
            catch (Exception ex)
            {
                throw (ex);
            }
            finally
            {
                if (sr != null) { sr.Close(); }
                if (stream != null) { stream.Close(); }
                if (response != null) { response.Close(); }
            }
        }

        /// <summary>  
        /// 创建POST方式的HTTP请求  
        /// </summary>  
        /// <param name="url">请求的URL</param>  
        /// <param name="parameters">随同请求POST的参数名称及参数值字典</param>  
        /// <param name="timeout">请求的超时时间</param>  
        /// <param name="userAgent">请求的客户端浏览器信息，可以为空</param>  
        /// <param name="requestEncoding">发送HTTP请求时所用的编码</param>  
        /// <param name="cookies">随同HTTP请求发送的Cookie信息，如果不需要身份验证可以为空</param>  
        /// <returns></returns>  
        public static HttpWebResponse CreatePostHttpResponse(string url, object postData, int? timeout, string userAgent, Encoding requestEncoding, CookieCollection cookies)
        {
            if (string.IsNullOrEmpty(url))
            {
                return null;
            }
            if (requestEncoding == null)
            {
                requestEncoding = System.Text.Encoding.UTF8;
            }
            HttpWebRequest request = null;
            HttpWebResponse response = null;
            try
            {
                //如果是发送HTTPS请求  
                if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
                {
                    ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
                    request = WebRequest.Create(url) as HttpWebRequest;
                    request.ProtocolVersion = HttpVersion.Version10;
                }
                else
                {
                    request = WebRequest.Create(url) as HttpWebRequest;
                }
                request.Method = "POST";
                request.ContentType = "application/x-www-form-urlencoded";
                if (!string.IsNullOrEmpty(userAgent))
                {
                    request.UserAgent = userAgent;
                }
                else
                {
                    request.UserAgent = DefaultUserAgent;
                }
                if (timeout.HasValue)
                {
                    request.Timeout = timeout.Value;
                }
                if (cookies != null)
                {
                    request.CookieContainer = new CookieContainer();
                    request.CookieContainer.Add(cookies);
                }
                string strBuffer = string.Empty;
                if (postData is string)
                {
                    strBuffer = (string)postData;
                }
                else if (postData is IDictionary<string, string>)
                {
                    IDictionary<string, string> parameters = (IDictionary<string, string>)postData;
                    //如果需要POST数据  
                    if (!(parameters == null || parameters.Count == 0))
                    {
                        StringBuilder buffer = new StringBuilder();
                        int i = 0;
                        foreach (string key in parameters.Keys)
                        {
                            if (i > 0)
                            {
                                buffer.AppendFormat("&{0}={1}", key, parameters[key]);
                            }
                            else
                            {
                                buffer.AppendFormat("{0}={1}", key, parameters[key]);
                            }
                            i++;
                        }
                        strBuffer = buffer.ToString();
                    }
                }
                byte[] data = requestEncoding.GetBytes(strBuffer.ToString());
                using (Stream stream = request.GetRequestStream())
                {
                    stream.Write(data, 0, data.Length);
                }
                response = request.GetResponse() as HttpWebResponse;
                return response;
            }
            catch (Exception ex)
            {
                if (response != null)
                {
                    response.Close();
                }
                throw (ex);
            }
        }

        public static string CreatePostGetString(string url, object postData, int? timeout, string userAgent, Encoding requestEncoding, CookieCollection cookies)
        {
            HttpWebResponse response = null;
            Stream stream = null;
            StreamReader sr = null;
            try
            {
                response = CreatePostHttpResponse(url, postData, timeout, userAgent, requestEncoding, cookies);
                if (response == null)
                {
                    return string.Empty;
                }
                stream = response.GetResponseStream();
                sr = new StreamReader(stream);
                string strResult = sr.ReadToEnd();
                return strResult;
            }
            catch (Exception ex)
            {
                throw (ex);
            }
            finally
            {
                if (sr != null) { sr.Close(); }
                if (stream != null) { stream.Close(); }
                if (response != null) { response.Close(); }
            }
        }

        private static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
        {
            return true; //总是接受  
        }
    }
}