using System.Security.Claims;
using System.Security.Cryptography;
using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using static System.Net.Mime.MediaTypeNames;
using Microsoft.Net.Http.Headers;
using Microsoft.Extensions.Configuration;
using NPOI.SS.Formula.Functions;

namespace OASystem.API.OAMethodLib.APNs
{
    public enum NotificationType : int
    {
        Alert = 0,
        Sound = 1,
        Badge = 2,
        Silent = 3
    }

    /// <summary>
    /// APNs 生成 JWT token，添加服务的时候，使用单利
    /// </summary>
    public class APNsService : IAPNsService
    {
        static string token = null;
        static string baseUrl = null;

        private readonly IConfiguration _configuration;
        private readonly IHttpClientFactory _httpClientFactory;
        public APNsService(IConfiguration configuration, IHttpClientFactory httpClientFactory)
        {
            this._configuration = configuration;
            this._httpClientFactory = httpClientFactory;

            //APNsService.baseUrl = this._configuration["apple:pushNotificationServer"];
            APNsService.baseUrl = this._configuration["apple:pushNotificationServer_Production"];
        }

        /// <summary>
        /// 生成 APNs JWT token
        /// </summary>
        /// <returns></returns>
        public string GetnerateAPNsJWTToken()
        {
            return this.GetnerateAPNsJWTToken(APNsService.token);
        }

        /// <summary>
        /// 生成 APNs JWT token
        /// </summary>
        /// <returns></returns>
        private string GetnerateAPNsJWTToken(string oldToken)
        {
            var tokenHandler = new JwtSecurityTokenHandler();
            var iat = ((DateTime.UtcNow.Ticks - new DateTime(1970, 1, 1).Ticks) / TimeSpan.TicksPerSecond);

            // 判断原 token 是否超过 50 分钟，如果未超过，直接返回
            if (string.IsNullOrWhiteSpace(oldToken) == false)
            {
                JwtPayload oldPayload = tokenHandler.ReadJwtToken(oldToken).Payload;
                var oldIat = oldPayload.Claims.FirstOrDefault(c => c.Type == "iat");
                if (oldIat != null)
                {
                    if (long.TryParse(oldIat.Value, out long oldIatValue) == true)
                    {
                        // 两次间隔小于 50 分钟，使用原 token
                        if ((iat - oldIatValue) < (50 * 60))
                        {
                            return oldToken;
                        }
                    }
                }
            }

            var kid = _configuration["apple:kid"];
            var securityKey = _configuration["apple:securityKey"].Replace("\n", "");
            var iss = _configuration["apple:iss"];

            var claims = new Claim[]
            {
            new Claim("iss", iss),
            new Claim("iat", iat.ToString())
            };

            var eCDsa = ECDsa.Create();

            eCDsa.ImportPkcs8PrivateKey(Convert.FromBase64String(securityKey), out _);

            var key = new ECDsaSecurityKey(eCDsa);

            key.KeyId = kid;

            var signingCredentials = new SigningCredentials(key, SecurityAlgorithms.EcdsaSha256);
            var jwtHeader = new JwtHeader(signingCredentials);
            var jwtPayload = new JwtPayload(claims);

            var jwtSecurityToken = new JwtSecurityToken(jwtHeader, jwtPayload);

            APNsService.token = tokenHandler.WriteToken(jwtSecurityToken);

            return APNsService.token;
        }

        /// <summary>
        /// 发送推送通知
        /// </summary>
        /// <param name="apnsTopic">APP Id</param>
        /// <param name="deviceToken">设备标识</param>
        /// <param name="type">通知类型</param>
        /// <param name="title">标题</param>
        /// <param name="subtitle">子标题</param>
        /// <param name="body">通知内容</param>
        /// <returns></returns>
        public async Task<string> PushNotification(string apnsTopic, string deviceToken, NotificationType type, string title, string subtitle, string body)
        {
            var responseData = FailedAPNsReponseData();
            var token = this.GetnerateAPNsJWTToken();
            var httpRequestMessage = new HttpRequestMessage(HttpMethod.Post, APNsService.baseUrl + deviceToken)
            {
                Headers =
            {
                { HeaderNames.Authorization, "bearer " +  token },
                { "apns-topic", apnsTopic },
                { "apns-expiration", "0" }
            },
                Version = new Version(2, 0)
            };

            var notContent = new
            {
                aps = new
                {
                    alert = new
                    {
                        title = title,
                        subtitle = subtitle,
                        body = body
                    }
                }
            };
            //var content = new StringContent(JsonSerializerTool.SerializeDefault(notContent), System.Text.Encoding.UTF8, Application.Json);

            var content = new StringContent(System.Text.Json.JsonSerializer.Serialize(notContent));

            httpRequestMessage.Content = content;

            var httpClient = _httpClientFactory.CreateClient();
            try
            {
                var httpResponseMessage = await httpClient.SendAsync(httpRequestMessage);

                if (httpResponseMessage.IsSuccessStatusCode)
                {
                    responseData.Code = 200;
                    return System.Text.Json.JsonSerializer.Serialize(responseData);
                }
                else
                {
                    responseData.Data = httpResponseMessage.StatusCode;
                    return System.Text.Json.JsonSerializer.Serialize(responseData);
                }
            }
            catch (Exception e)
            {
                responseData.Data = e.Message;
                return System.Text.Json.JsonSerializer.Serialize(responseData);
            }
        }

        public APNsReponseData FailedAPNsReponseData()
        {
            return new APNsReponseData() { Code = 400, Data = "" };
        }
    }

    public class APNsReponseData
    {
        public int Code { get; set; } = 0;

        public object Data { get; set; } = "";

    }

   
}