namespace DS.Module.HkOpenApi;

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

public class HttpUtillib
{
    /// <summary>
    /// 设置信息参数
    /// </summary>
    /// <param name="appkey">合作方APPKey</param>
    /// <param name="secret">合作方APPSecret</param>
    /// <param name="ip">平台IP</param>
    /// <param name="port">平台端口，默认HTTPS的443端口</param>
    /// <param name="isHttps">是否启用HTTPS协议，默认HTTPS</param>
    /// <return></return>
    public static void SetPlatformInfo(string appkey, string secret, string ip, int port = 443, bool isHttps = true)
    {
        _appkey = appkey;
        _secret = secret;
        _ip = ip;
        _port = port;
        _isHttps = isHttps;

        // 设置并发数，如不设置默认为2
        ServicePointManager.DefaultConnectionLimit = 512;
    }

    /// <summary>
    /// HTTP GET请求
    /// </summary>
    /// <param name="uri">HTTP接口Url，不带协议和端口，如/artemis/api/resource/v1/cameras/indexCode?cameraIndexCode=a10cafaa777c49a5af92c165c95970e0</param>
    /// <param name="timeout">请求超时时间，单位：秒</param>
    /// <returns></returns>
    public static byte[] HttpGet(string uri, int timeout)
    {
        Dictionary<string, string> header = new Dictionary<string, string>();

        // 初始化请求：组装请求头，设置远程证书自动验证通过
        initRequest(header, uri, "", false);

        // build web request object
        StringBuilder sb = new StringBuilder();
        sb.Append(_isHttps ? "https://" : "http://").Append(_ip).Append(":").Append(_port.ToString()).Append(uri);

        HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(sb.ToString());
        req.KeepAlive = false;
        req.ProtocolVersion = HttpVersion.Version11;
        req.AllowAutoRedirect = false; // 不允许自动重定向
        req.Method = "GET";
        req.Timeout = timeout * 1000; // 传入是秒，需要转换成毫秒
        req.Accept = header["Accept"];
        req.ContentType = header["Content-Type"];

        foreach (string headerKey in header.Keys)
        {
            if (headerKey.Contains("x-ca-"))
            {
                req.Headers.Add(headerKey + ":" + header[headerKey]);
            }
        }

        HttpWebResponse rsp = null;
        try
        {
            rsp = (HttpWebResponse)req.GetResponse();
            if (HttpStatusCode.OK == rsp.StatusCode)
            {
                Stream rspStream = rsp.GetResponseStream(); // 响应内容字节流
                StreamReader sr = new StreamReader(rspStream);
                string strStream = sr.ReadToEnd();
                long streamLength = strStream.Length;
                byte[] response = System.Text.Encoding.UTF8.GetBytes(strStream);
                rsp.Close();
                return response;
            }
            else if (HttpStatusCode.Found == rsp.StatusCode ||
                     HttpStatusCode.Moved == rsp.StatusCode) // 302/301 redirect
            {
                string reqUrl = rsp.Headers["Location"].ToString(); // 获取重定向URL
                WebRequest wreq = WebRequest.Create(reqUrl); // 重定向请求对象
                WebResponse wrsp = wreq.GetResponse(); // 重定向响应
                long streamLength = wrsp.ContentLength; // 重定向响应内容长度
                Stream rspStream = wrsp.GetResponseStream(); // 响应内容字节流
                byte[] response = new byte[streamLength];
                rspStream.Read(response, 0, (int)streamLength); // 读取响应内容至byte数组
                rspStream.Close();
                rsp.Close();
                return response;
            }

            rsp.Close();
        }
        catch (WebException e)
        {
            if (rsp != null)
            {
                rsp.Close();
            }
        }

        return null;
    }

    /// <summary>
    /// HTTP Post请求
    /// </summary>
    /// <param name="uri">HTTP接口Url，不带协议和端口，如/artemis/api/resource/v1/org/advance/orgList</param>
    /// <param name="body">请求参数</param>
    /// <param name="timeout">请求超时时间，单位：秒</param>
    /// <return>请求结果</return>
    public static string HttpPost(string uri, string body, int timeout)
    {
        Dictionary<string, string> header = new Dictionary<string, string>();

        // 初始化请求：组装请求头，设置远程证书自动验证通过
        initRequest(header, uri, body, true);

        // build web request object
        StringBuilder sb = new StringBuilder();
        sb.Append(_isHttps ? "https://" : "http://").Append(_ip).Append(":").Append(_port.ToString()).Append(uri);

        // 创建POST请求
        HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(sb.ToString());
        req.KeepAlive = false;
        req.ProtocolVersion = HttpVersion.Version11;
        req.AllowAutoRedirect = false; // 不允许自动重定向
        req.Method = "POST";
        req.Timeout = timeout * 1000; // 传入是秒，需要转换成毫秒
        req.Accept = header["Accept"];
        req.ContentType = header["Content-Type"];
        req.UserAgent = "PostmanRuntime/7.26.8";

        foreach (string headerKey in header.Keys)
        {
            if (headerKey.Contains("x-ca-"))
            {
                req.Headers.Add(headerKey + ":" + header[headerKey]);
            }
        }
        byte[] data = Encoding.UTF8.GetBytes(body);
        
        req.ContentLength = data.Length;
        
        using (Stream reqStream = req.GetRequestStream())
        {
            reqStream.Write(data, 0, data.Length);
        
            reqStream.Close();
        }

        HttpWebResponse response = (HttpWebResponse)req.GetResponse();
        Stream stream = response.GetResponseStream();
        Encoding encode = Encoding.UTF8;
        StreamReader reader = new StreamReader(stream, encode);
        string content = reader.ReadToEnd();
        stream.Close();
        reader.Close(); 
        return content;
        // if (!string.IsNullOrWhiteSpace(body))
        // {
        //     byte[] postBytes = Encoding.UTF8.GetBytes(body);
        //     req.ContentLength = postBytes.Length;
        //     Stream reqStream = null;
        //
        //     try
        //     {
        //         reqStream = req.GetRequestStream();
        //         reqStream.Write(postBytes, 0, postBytes.Length);
        //         reqStream.Close();
        //     }
        //     catch (WebException e)
        //     {
        //         if (reqStream != null)
        //         {
        //             reqStream.Close();
        //         }
        //
        //         return null;
        //     }
        // }
        //
        // HttpWebResponse rsp = null;
        // try
        // {
        //     rsp = (HttpWebResponse)req.GetResponse();
        //     if (HttpStatusCode.OK == rsp.StatusCode)
        //     {
        //         Stream rspStream = rsp.GetResponseStream();
        //         StreamReader sr = new StreamReader(rspStream);
        //         string strStream = sr.ReadToEnd();
        //         long streamLength = strStream.Length;
        //         byte[] response = System.Text.Encoding.UTF8.GetBytes(strStream);
        //         rsp.Close();
        //         return response;
        //     }
        //     else if (HttpStatusCode.Found == rsp.StatusCode ||
        //              HttpStatusCode.Moved == rsp.StatusCode) // 302/301 redirect
        //     {
        //         try
        //         {
        //             string reqUrl = rsp.Headers["Location"].ToString(); // 如需要重定向URL，请自行修改接口返回此参数
        //             rsp.Close();
        //             WebRequest wreq = WebRequest.Create(reqUrl);
        //             rsp = (HttpWebResponse)wreq.GetResponse();
        //             Stream rspStream = rsp.GetResponseStream();
        //             long streamLength = rsp.ContentLength;
        //             int offset = 0;
        //             byte[] response = new byte[streamLength];
        //             while (streamLength > 0)
        //             {
        //                 int n = rspStream.Read(response, offset, (int)streamLength);
        //                 if (0 == n)
        //                 {
        //                     break;
        //                 }
        //
        //                 offset += n;
        //                 streamLength -= n;
        //             }
        //
        //             return response;
        //         }
        //         catch (Exception e)
        //         {
        //             rsp.Close();
        //             return null;
        //         }
        //     }
        //
        //     rsp.Close();
        // }
        // catch (WebException e)
        // {
        //     if (rsp != null)
        //     {
        //         rsp.Close();
        //     }
        // }

        // return null;
    }

    private static void initRequest(Dictionary<string, string> header, string url, string body, bool isPost)
    {
        // Accept                
        // string accept = "application/json"; // "*/*";
        string accept = "*/*"; // "*/*";
        header.Add("Accept", accept);

        // ContentType  
        string contentType = "application/json";
        header.Add("Content-Type", contentType);

        // if (isPost)
        // {
        //     // content-md5，be careful it must be lower case.
        //     string contentMd5 = computeContentMd5(body);
        //     header.Add("content-md5", contentMd5);
        // }

        // // x-ca-timestamp
        // string timestamp =
        //     ((DateTime.Now.Ticks -
        //       TimeZone.CurrentTimeZone.ToLocalTime(new System.DateTime(1970, 1, 1, 0, 0, 0, 0)).Ticks) / 1000)
        //     .ToString();
        // header.Add("x-ca-timestamp", timestamp);
        //
        // // x-ca-nonce
        // string nonce = System.Guid.NewGuid().ToString();
        // header.Add("x-ca-nonce", nonce);

        // x-ca-key
        header.Add("x-ca-key", _appkey);

        // build string to sign
        string strToSign = buildSignString(isPost ? "POST" : "GET", url, header);
        string signedStr = computeForHMACSHA256(strToSign, _secret);

        // x-ca-signature
        header.Add("x-ca-signature", signedStr);

        if (_isHttps)
        {
            // set remote certificate Validation auto pass
            ServicePointManager.ServerCertificateValidationCallback =
                new System.Net.Security.RemoteCertificateValidationCallback(remoteCertificateValidate);
            // FIX：修复不同.Net版对一些SecurityProtocolType枚举支持情况不一致导致编译失败等问题，这里统一使用数值
            // ServicePointManager.SecurityProtocol = (SecurityProtocolType)48 | (SecurityProtocolType)3072 | 
            //                                        (SecurityProtocolType)768 | (SecurityProtocolType)192 ;
            // ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;
        }
    }

    /// <summary>
    /// 计算content-md5
    /// </summary>
    /// <param name="body"></param>
    /// <returns>base64后的content-md5</returns>
    private static string computeContentMd5(string body)
    {
        MD5 md5 = new MD5CryptoServiceProvider();
        byte[] result = md5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(body));
        return Convert.ToBase64String(result);
    }

    /// <summary>
    /// 远程证书验证
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="cert"></param>
    /// <param name="chain"></param>
    /// <param name="error"></param>
    /// <returns>验证是否通过，始终通过</returns>
    private static bool remoteCertificateValidate(object sender, X509Certificate cert, X509Chain chain,
        SslPolicyErrors error)
    {
        return true;
    }

    /// <summary>
    /// 计算HMACSHA265
    /// </summary>
    /// <param name="str">待计算字符串</param>
    /// <param name="secret">平台APPSecet</param>
    /// <returns>HMAXH265计算结果字符串</returns>
    private static string computeForHMACSHA256(string str, string secret)
    {
        var encoder = new System.Text.UTF8Encoding();
        byte[] secretBytes = encoder.GetBytes(secret);
        byte[] strBytes = encoder.GetBytes(str);
        var opertor = new HMACSHA256(secretBytes);
        byte[] hashbytes = opertor.ComputeHash(strBytes);
        return Convert.ToBase64String(hashbytes);
    }

    /// <summary>
    /// 计算签名字符串
    /// </summary>
    /// <param name="method">HTTP请求方法，如“POST”</param>
    /// <param name="url">接口Url，如/artemis/api/resource/v1/org/advance/orgList</param>
    /// <param name="header">请求头</param>
    /// <returns>签名字符串</returns>
    private static string buildSignString(string method, string url, Dictionary<string, string> header)
    {
        StringBuilder sb = new StringBuilder();
        sb.Append(method.ToUpper()).Append("\n");
        if (null != header)
        {
            if (null != header["Accept"])
            {
                sb.Append((string)header["Accept"]);
                sb.Append("\n");
            }

            if (header.Keys.Contains("Content-MD5") && null != header["Content-MD5"])
            {
                sb.Append((string)header["Content-MD5"]);
                sb.Append("\n");
            }

            if (null != header["Content-Type"])
            {
                sb.Append((string)header["Content-Type"]);
                sb.Append("\n");
            }

            if (header.Keys.Contains("Date") && null != header["Date"])
            {
                sb.Append((string)header["Date"]);
                sb.Append("\n");
            }
        }

        // build and add header to sign
        string signHeader = buildSignHeader(header);
        sb.Append(signHeader);
        sb.Append(url);
        return sb.ToString();
    }

    /// <summary>
    /// 计算签名头
    /// </summary>
    /// <param name="header">请求头</param>
    /// <returns>签名头</returns>
    private static string buildSignHeader(Dictionary<string, string> header)
    {
        Dictionary<string, string> sortedDicHeader = new Dictionary<string, string>();
        sortedDicHeader = header;
        var dic = from objDic in sortedDicHeader orderby objDic.Key ascending select objDic;

        StringBuilder sbSignHeader = new StringBuilder();
        StringBuilder sb = new StringBuilder();
        foreach (KeyValuePair<string, string> kvp in dic)
        {
            if (kvp.Key.Replace(" ", "").Contains("x-ca-"))
            {
                sb.Append(kvp.Key + ":");
                if (!string.IsNullOrWhiteSpace(kvp.Value))
                {
                    sb.Append(kvp.Value);
                }

                sb.Append("\n");
                if (sbSignHeader.Length > 0)
                {
                    sbSignHeader.Append(",");
                }

                sbSignHeader.Append(kvp.Key);
            }
        }

        header.Add("x-ca-signature-headers", sbSignHeader.ToString());

        return sb.ToString();
    }

    /// <summary>
    /// 平台ip
    /// </summary>
    private static string _ip;

    /// <summary>
    /// 平台端口
    /// </summary>
    private static int _port = 443;

    /// <summary>
    /// 平台APPKey
    /// </summary>
    private static string _appkey;

    /// <summary>
    /// 平台APPSecret
    /// </summary>
    private static string _secret;

    /// <summary>
    /// 是否使用HTTPS协议
    /// </summary>
    private static bool _isHttps = true;
     
}