using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace RS.Common
{
    /// <summary>
    /// 请求类型
    /// </summary>
    public enum EnumHttpVerb
    {
        GET,
        POST,
        PUT,
        DELETE
    }
    /// <summary>
    /// REST FUL接口类
    /// </summary>
    public class RestClient
    {
        #region 属性
        /// <summary>
        /// 端点路径
        /// </summary>
        public string EndPoint { get; set; }

        /// <summary>
        /// 请求方式
        /// </summary>
        public EnumHttpVerb Method { get; set; }

        /// <summary>
        /// 文本类型（1、application/json 2、txt/html）
        /// </summary>
        public string ContentType { get; set; }

        /// <summary>
        /// 请求的数据(一般为JSon格式)
        /// </summary>
        public string PostData { get; set; }
        #endregion

        #region 初始化
        public RestClient()
        {
            EndPoint = "";
            Method = EnumHttpVerb.GET;
            ContentType = "application/json";
            PostData = "";
        }

        public RestClient(string endpoint)
        {
            EndPoint = endpoint;
            Method = EnumHttpVerb.GET;
            ContentType = "application/json";
            PostData = "";
        }

        public RestClient(string endpoint, EnumHttpVerb method)
        {
            EndPoint = endpoint;
            Method = method;
            ContentType = "application/json";
            PostData = "";
        }

        public RestClient(string endpoint, EnumHttpVerb method, string postData)
        {
            EndPoint = endpoint;
            Method = method;
            ContentType = "application/json";
            PostData = postData;
        }
        #endregion

        #region 方法
        /// <summary>
        /// http请求(不带参数请求)
        /// </summary>
        /// <returns></returns>
        public string HttpRequest()
        {
            return HttpRequest("");
        }

        /// <summary>
        /// http请求(带参数)
        /// </summary>
        /// <param name="parameters">parameters例如：?name=LiLei</param>
        /// <returns></returns>
        public string HttpRequest(string parameters)
        {
            try
            {
                var request = (HttpWebRequest)WebRequest.Create(EndPoint + parameters);

                request.Method = Method.ToString();
                request.ContentLength = 0;
                request.ContentType = ContentType;

                if (!string.IsNullOrEmpty(PostData) && Method == EnumHttpVerb.POST)
                {
                    var bytes = Encoding.UTF8.GetBytes(PostData);
                    request.ContentLength = bytes.Length;

                    using (var writeStream = request.GetRequestStream())
                    {
                        writeStream.Write(bytes, 0, bytes.Length);
                    }
                }

                using (var response = (HttpWebResponse)request.GetResponse())
                {
                    var responseValue = string.Empty;

                    if (response.StatusCode != HttpStatusCode.OK)
                    {
                        var message = string.Format("请求数据失败. 返回的 HTTP 状态码：{0}", response.StatusCode);
                        throw new ApplicationException(message);
                    }

                    using (var responseStream = response.GetResponseStream())
                    {
                        if (responseStream != null)
                            using (var reader = new StreamReader(responseStream))
                            {
                                responseValue = reader.ReadToEnd();
                            }
                    }
                    return responseValue;
                }
            }
            catch (Exception ex)
            {
                return ex.ToString();
            }

        }
        #endregion
    }
}