using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using POSV.Entity;
using POSV.HttpApi;
using POSV.LoadBalance;

namespace POSV.Utils
{
    public class OpenApiUtils
    {
        static NLog.Logger logger = NLog.LogManager.GetCurrentClassLogger();

        private static object _lock = new object();

        private static OpenApiUtils _instance = null;

        /// <summary>
        /// 数据表中配置的API接口
        /// </summary>
        private Dictionary<string,Apis> _apis;

        /// <summary>
        /// 数据表中API接口对应的URL列表
        /// </summary>
        private Dictionary<string , List<OpenApi>> _urls;

        public static OpenApiUtils Instance
        {
            get
            {
                if (_instance == null)
                {
                    lock (_lock)
                    {
                        _instance = new OpenApiUtils();

                        _instance.Init();
                    }
                }
                return _instance;
            }
        }

        private void Init()
        {
            this._apis = new Dictionary<string , Apis>();

            this._urls = new Dictionary<string , List<OpenApi>>();

            Tuple<List<Apis> , List<Urls>> result = null;

            using (var db = Global.Instance.OpenDataBase)
            {
                result = db.FetchMultiple<Apis , Urls>(SqlConstant.ApisQueryAll + SqlConstant.UrlsQueryAll);
            }

            if (result != null)
            {
                var apis = result.Item1;

                var urls = result.Item2;

                foreach (var api in apis)
                {
                    this._apis[api.ApiType] = api;

                    //查找ApiType匹配的全部URLS
                    var servers = urls.FindAll(x => x.ApiType == api.ApiType);

                    if (servers != null && servers.Count > 0)
                    {
                        var list = new List<OpenApi>();
                        foreach (var url in servers)
                        {
                            var openApi = new OpenApi();

                            openApi.Url = string.Format("{0}://{1}/{2}/api" , url.Protocol , url.Url , url.ContextPath);

                            openApi.Open = string.Format("{0}://{1}/{2}/open/api/extend" , url.Protocol , url.Url , url.ContextPath);

                            openApi.ApiType = (ApiType)Enum.Parse(typeof(ApiType) , url.ApiType);

                            openApi.AppKey = api.AppKey;
                            openApi.AppSecret = api.AppSecret;
                            openApi.Client = api.Client;
                            openApi.Locale = api.Locale;
                            openApi.Format = api.Format;
                            openApi.Version = api.Version;

                            openApi.Memo = url.Memo;

                            list.Add(openApi);
                        }

                        this._urls[api.ApiType] = list;
                    }
                }
            }
        }


        public void Refresh()
        {
            lock (_lock)
            {
                //Global.Instance.ReloadConfig(ConfigConstant.CONFIG_GROUP_SYSTEM);

                Init();
            }
        }


        public OpenApi NextApi(ApiType api)
        {
            IRouting<OpenApi> routing = null;
            if (!this._apis.ContainsKey(api.ToString())) {
                return null;
            }
            string balance = this._apis[api.ToString()].Routing + "";
            switch (balance)
            {
                case "0"://随机
                    routing = new RandomRouting<OpenApi>();
                    break;
                case "1"://轮询
                    routing = new RoundRobinRouting<OpenApi>(this._urls.Values.Count);
                    break;
                case "2"://一致性Hash
                    routing = new ConsistentHashRouting<OpenApi>(this._urls.Values.Count);
                    break;
                case "3"://一致性Hash
                    routing = new ConsistentHashRouting<OpenApi>(this._urls.Values.Count);
                    break;
                default:
                    routing = new RandomRouting<OpenApi>();
                    break;
            }

            var apis = routing.select("juweiyun.cn" , this._urls[api.ToString()].ToArray());

            return apis;
        }
        
        /// <summary>
        /// 获取当前时间戳，兼容Java服务端
        /// </summary>
        /// <returns></returns>
        public string GetTimestamp()
        {
            TimeSpan ts = new TimeSpan(DateTime.UtcNow.Ticks - new DateTime(1970 , 1 , 1 , 0 , 0 , 0).Ticks);

            return Convert.ToString((long)ts.TotalMilliseconds);
        }


        public SortedList<string , string> NewParameters(OpenApi api)
        {
            SortedList<string , string> parameters = new SortedList<string , string>();
            parameters.Add("appKey" , api.AppKey);
            parameters.Add("format" , api.Format);
            parameters.Add("locale" , api.Locale);
            parameters.Add("timestamp" , GetTimestamp());
            parameters.Add("client" , api.Client);
            parameters.Add("v" , api.Version);

            return parameters;
        }

        /// <summary>
        /// 开放平台签名算法
        /// </summary>
        /// <param name="parameters"></param>
        /// <returns></returns>
        public string Sign(OpenApi api , SortedList<string , string> parameters)
        {
            return Sign(api , parameters , null);
        }

        /// <summary>
        /// 开放平台签名算法
        /// </summary>
        /// <param name="parameters"></param>
        /// <returns></returns>
        public string Sign(OpenApi api , SortedList<string , string> parameters , List<string> ignoreParameters)
        {
            IList<string> keys = parameters.Keys;

            var paramNames = new List<string>(keys.Count);
            paramNames.AddRange(keys);
            if (ignoreParameters != null && ignoreParameters.Count > 0)
            {
                foreach (string ignore in ignoreParameters)
                {
                    paramNames.Remove(ignore);
                }
            }

            StringBuilder input = new StringBuilder();
            input.Append(api.AppSecret);
            foreach (string key in paramNames)
            {
                input.Append(key + parameters[key]);
            }
            input.Append(api.AppSecret);

            SHA1 sha1 = new SHA1CryptoServiceProvider();//建立一个SHA1
            byte[] source = Encoding.UTF8.GetBytes(input.ToString());//将字符串转为Byte[]
            byte[] crypto = sha1.ComputeHash(source);//进行SHA1加密

            return ByteArrayToHexString(crypto);//把加密后的字符串从Byte[]转为字符串
        }

        /// <summary>
        /// 字节数组转十六进制字符串
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public string ByteArrayToHexString(byte[] data)
        {
            StringBuilder sb = new StringBuilder(data.Length * 3);
            foreach (byte b in data)
            {
                sb.Append(Convert.ToString(b , 16).PadLeft(2 , '0'));
            }
            return sb.ToString().ToUpper();

        }

    }
}