#region Apache License Version 2.0
/*----------------------------------------------------------------

Copyright 2019 Jeffrey Su & Suzhou Senparc Network Technology Co.,Ltd.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the
License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
either express or implied. See the License for the specific language governing permissions
and limitations under the License.

Detail: https://github.com/JeffreySu/WeiXinMPSDK/blob/master/license.md

----------------------------------------------------------------*/
#endregion Apache License Version 2.0

/*----------------------------------------------------------------
    Copyright (C) 2019 Senparc
    
    文件名：MessageHandler.cs
    文件功能描述：微信请求的集中处理方法
    
    
    创建标识：Senparc - 20150211
    
    修改标识：Senparc - 20150303
    修改描述：整理接口
    
    修改标识：Senparc - 20150327
    修改描述：添加接收小视频消息方法

    修改标识：Senparc - 20151205
    修改描述：v13.4.5 提供OmitRepeatedMessageFunc方法增强消息去重灵活性
  
    修改标识：Senparc - 20160722
    修改描述：记录上下文，此处修改

    修改标识：Senparc - 20180122
    修改描述：OnExecuting() 和 OnExecuted() 方法改为 override

    修改标识：Senparc - 20180318
    修改描述：v14.10.7 MessageHandler消息去重增加对“领取事件推送”的特殊判断 - https://github.com/JeffreySu/WeiXinMPSDK/issues/1106

    修改标识：Senparc - 20181030
    修改描述：v16.4.10 优化 MessageHandler 构造函数，提供 PostModel 默认值

    修改标识：Senparc - 20181117
    修改描述：v16.5.0 Execute() 重写方法名称改为 BuildResponseMessage()

----------------------------------------------------------------*/

using Senparc.CO2NET.Extensions;
using Senparc.NeuChar;
using Senparc.NeuChar.ApiHandlers;
using Senparc.NeuChar.Context;
using Senparc.NeuChar.Entities;
using Senparc.NeuChar.Helpers;
using Senparc.NeuChar.MessageHandlers;
using Senparc.Weixin.Exceptions;
using Senparc.Weixin.MP.AdvancedAPIs;
using Senparc.Weixin.MP.AppStore;
using Senparc.Weixin.MP.Entities;
using Senparc.Weixin.MP.Entities.Request;
using Senparc.Weixin.Tencent;
using System;
using System.IO;
using System.Threading.Tasks;
using System.Xml.Linq;

namespace Senparc.Weixin.MP.MessageHandlers
{
    /// <summary>
    /// 微信请求的集中处理方法
    /// 此方法中所有过程，都基于Senparc.Weixin.MP的基础功能，只为简化代码而设。
    /// </summary>
    public abstract partial class MessageHandler<TC> :
        MessageHandler<TC, IRequestMessageBase, IResponseMessageBase>, IMessageHandler
        where TC : class, IMessageContext<IRequestMessageBase, IResponseMessageBase>, new()
    {
        /// <summary>
        /// 上下文（仅限于当前MessageHandler基类内）
        /// </summary>
        public static GlobalMessageContext<TC, IRequestMessageBase, IResponseMessageBase> GlobalWeixinContext = new GlobalMessageContext<TC, IRequestMessageBase, IResponseMessageBase>();
        //TODO:这里如果用一个MP自定义的WeixinContext，继承WeixinContext<TC, IRequestMessageBase, IResponseMessageBase>，在下面的WeixinContext中将无法转换成基类要求的类型


        /// <summary>
        /// 全局消息上下文
        /// </summary>
        public override GlobalMessageContext<TC, IRequestMessageBase, IResponseMessageBase> GlobalMessageContext
        {
            get
            {
                return GlobalWeixinContext;
            }
        }

        ///// <summary>
        ///// 原始的加密请求（如果不加密则为null）
        ///// </summary>
        //public XDocument EcryptRequestDocument { get; set; }

        /// <summary>
        /// 根据ResponseMessageBase获得转换后的ResponseDocument
        /// 注意：这里每次请求都会根据当前的ResponseMessageBase生成一次，如需重用此数据，建议使用缓存或局部变量
        /// </summary>
        public override XDocument ResponseDocument
        {
            get
            {
                return ResponseMessage != null ? EntityHelper.ConvertEntityToXml(ResponseMessage as ResponseMessageBase) : null;
            }
        }

        /// <summary>
        /// 最后返回的ResponseDocument。
        /// 这里是Senparc.Weixin.MP，根据请求消息半段在ResponseDocument基础上是否需要再次进行加密（每次获取重新加密，所以结果会不同）
        /// </summary>
        public override XDocument FinalResponseDocument
        {
            get
            {
                if (ResponseDocument == null)
                {
                    return null;
                }

                if (!UsingEcryptMessage)
                {
                    return ResponseDocument;
                }

                var timeStamp = SystemTime.Now.Ticks.ToString();
                var nonce = SystemTime.Now.Ticks.ToString();

                WXBizMsgCrypt msgCrype = new WXBizMsgCrypt(_postModel.Token, _postModel.EncodingAESKey, _postModel.AppId);
                string finalResponseXml = null;
                msgCrype.EncryptMsg(ResponseDocument.ToString().Replace("\r\n", "\n")/* 替换\r\n是为了处理iphone设备上换行bug */, timeStamp, nonce, ref finalResponseXml);//TODO:这里官方的方法已经把EncryptResponseMessage对应的XML输出出来了

                return XDocument.Parse(finalResponseXml);
            }
        }


        /// <summary>
        /// 请求实体
        /// </summary>
        public new IRequestMessageBase RequestMessage
        {
            get
            {
                return base.RequestMessage as IRequestMessageBase;
            }
            set
            {
                base.RequestMessage = value;
            }
        }

        /// <summary>
        /// 响应实体
        /// 正常情况下只有当执行Execute()方法后才可能有值。
        /// 也可以结合Cancel，提前给ResponseMessage赋值。
        /// </summary>
        public new IResponseMessageBase ResponseMessage
        {
            get
            {
                return base.ResponseMessage as IResponseMessageBase;
            }
            set
            {
                base.ResponseMessage = value;
            }
        }

        private PostModel _postModel;

        /// <summary>
        /// 微微嗨开发者信息
        /// </summary>
        public DeveloperInfo DeveloperInfo { get; set; }


        /// <summary>
        /// 动态去重判断委托，仅当返回值为false时，不使用消息去重功能
        /// </summary>
        public Func<IRequestMessageBase, bool> OmitRepeatedMessageFunc = null;


        /// <summary>
        /// 请求和响应消息定义
        /// </summary>
        public override MessageEntityEnlightener MessageEntityEnlightener { get { return MpMessageEntityEnlightener.Instance; } }
        /// <summary>
        /// Api 接口定义
        /// </summary>
        public override ApiEnlightener ApiEnlightener { get { return MpApiEnlightener.Instance; } }


        #region 私有方法

        /// <summary>
        /// 标记为已重复消息
        /// </summary>
        private void MarkRepeatedMessage()
        {
            CancelExcute = true;//重复消息，取消执行
            MessageIsRepeated = true;
        }

        #endregion

        /// <summary>
        /// 构造MessageHandler
        /// </summary>
        /// <param name="inputStream">请求消息流</param>
        /// <param name="postModel">PostModel</param>
        /// <param name="maxRecordCount">单个用户上下文消息列表储存的最大长度</param>
        /// <param name="developerInfo">微微嗨开发者信息，如果不为空，则优先请求云端应用商店的资源</param>
        public MessageHandler(Stream inputStream, PostModel postModel, int maxRecordCount = 0, DeveloperInfo developerInfo = null)
            : base(inputStream, postModel, maxRecordCount)
        {
            DeveloperInfo = developerInfo;
            postModel = postModel ?? new PostModel();
        }

        /// <summary>
        /// 构造MessageHandler
        /// </summary>
        /// <param name="requestDocument">请求消息的XML</param>
        /// <param name="postModel">PostModel</param>
        /// <param name="maxRecordCount">单个用户上下文消息列表储存的最大长度</param>
        /// <param name="developerInfo">微微嗨开发者信息，如果不为空，则优先请求云端应用商店的资源</param>
        public MessageHandler(XDocument requestDocument, PostModel postModel, int maxRecordCount = 0, DeveloperInfo developerInfo = null)
            : base(requestDocument, postModel, maxRecordCount)
        {
            DeveloperInfo = developerInfo;
            postModel = postModel ?? new PostModel();
            //GlobalMessageContext.MaxRecordCount = maxRecordCount;
            //Init(requestDocument);
        }

        /// <summary>
        /// 直接传入IRequestMessageBase，For UnitTest
        /// </summary>
        /// <param name="postModel">PostModel</param>
        /// <param name="maxRecordCount">单个用户上下文消息列表储存的最大长度</param>
        /// <param name="developerInfo">微微嗨开发者信息，如果不为空，则优先请求云端应用商店的资源</param>
        /// <param name="requestMessageBase"></param>
        public MessageHandler(RequestMessageBase requestMessageBase, PostModel postModel, int maxRecordCount = 0, DeveloperInfo developerInfo = null)
            : base(requestMessageBase, postModel, maxRecordCount)
        {
            DeveloperInfo = developerInfo;
            postModel = postModel ?? new PostModel();

            var postDataDocument = requestMessageBase.ConvertEntityToXml();
            base.CommonInitialize(postDataDocument, maxRecordCount, postModel);
        }

        /// <summary>
        /// 初始化
        /// </summary>
        /// <param name="postDataDocument"></param>
        /// <param name="postModel"></param>
        /// <returns></returns>
        public override XDocument Init(XDocument postDataDocument, IEncryptPostModel postModel)
        {
            //进行加密判断并处理
            _postModel = postModel as PostModel;
            var postDataStr = postDataDocument.ToString();

            XDocument decryptDoc = postDataDocument;

            if (_postModel != null && !_postModel.Token.IsNullOrWhiteSpace()
                && postDataDocument.Root.Element("Encrypt") != null && !string.IsNullOrEmpty(postDataDocument.Root.Element("Encrypt").Value))
            {
                //使用了加密
                UsingEcryptMessage = true;
                EcryptRequestDocument = postDataDocument;

                WXBizMsgCrypt msgCrype = new WXBizMsgCrypt(_postModel.Token, _postModel.EncodingAESKey, _postModel.AppId);
                string msgXml = null;
                var result = msgCrype.DecryptMsg(_postModel.Msg_Signature, _postModel.Timestamp, _postModel.Nonce, postDataStr, ref msgXml);

                //判断result类型
                if (result != 0)
                {
                    //验证没有通过，取消执行
                    CancelExcute = true;
                    return null;
                }

                if (postDataDocument.Root.Element("FromUserName") != null && !string.IsNullOrEmpty(postDataDocument.Root.Element("FromUserName").Value))
                {
                    //TODO：使用了兼容模式，进行验证即可
                    UsingCompatibilityModelEcryptMessage = true;
                }

                decryptDoc = XDocument.Parse(msgXml);//完成解密
            }

            RequestMessage = RequestMessageFactory.GetRequestEntity(decryptDoc);
            if (UsingEcryptMessage)
            {
                RequestMessage.Encrypt = postDataDocument.Root.Element("Encrypt").Value;
            }


            //TODO:分布式系统中本地的上下文会有同步问题，需要同步使用远程的储存
            if (MessageContextGlobalConfig.UseMessageContext)
            {
                var omit = OmitRepeatedMessageFunc == null || OmitRepeatedMessageFunc(RequestMessage);

                lock (MessageContextGlobalConfig.OmitRepeatLock)//TODO:使用分布式锁
                {
                    #region 消息去重

                    if (omit &&
                        OmitRepeatedMessage &&
                        CurrentMessageContext.RequestMessages.Count > 0
                         //&& !(RequestMessage is RequestMessageEvent_Merchant_Order)批量订单的MsgId可能会相同
                         )
                    {
                        //lastMessage必定有值（除非极端小的过期时间条件下，几乎不可能发生）
                        var lastMessage = CurrentMessageContext.RequestMessages[CurrentMessageContext.RequestMessages.Count - 1];

                        if (
                            //使用MsgId去重
                            (lastMessage.MsgId != 0 && lastMessage.MsgId == RequestMessage.MsgId) ||
                            //使用CreateTime去重（OpenId对象已经是同一个）
                            (lastMessage.MsgId == RequestMessage.MsgId &&
                                 lastMessage.CreateTime == RequestMessage.CreateTime &&
                                 lastMessage.MsgType == RequestMessage.MsgType)
                            )
                        {
                            MarkRepeatedMessage();//标记为已重复
                        }

                        //判断特殊事件
                        if (!MessageIsRepeated &&
                            lastMessage is RequestMessageEventBase &&
                            RequestMessage is RequestMessageEventBase &&
                            (lastMessage as RequestMessageEventBase).Event == (RequestMessage as RequestMessageEventBase).Event
                            )
                        {
                            var lastEventMessage = lastMessage as RequestMessageEventBase;
                            var currentEventMessage = RequestMessage as RequestMessageEventBase;
                            switch (lastEventMessage.Event)
                            {

                                case Event.user_get_card://领取事件推送
                                    //文档：https://mp.weixin.qq.com/wiki?t=resource/res_main&id=mp1451025274
                                    //问题反馈：https://github.com/JeffreySu/WeiXinMPSDK/issues/1106
                                    var lastGetUserCardMessage = lastMessage as RequestMessageEvent_User_Get_Card;
                                    var currentGetUserCardMessage = RequestMessage as RequestMessageEvent_User_Get_Card;
                                    if (lastGetUserCardMessage.UserCardCode == currentGetUserCardMessage.UserCardCode &&
                                        lastGetUserCardMessage.CardId == currentGetUserCardMessage.CardId)
                                    {
                                        MarkRepeatedMessage();//标记为已重复
                                    }
                                    break;
                                default:
                                    break;
                            }
                        }
                    }

                    #endregion

                    //在消息没有被去重的情况下记录上下文
                    if (!MessageIsRepeated)
                    {
                        GlobalMessageContext.InsertMessage(RequestMessage);
                    }
                }
            }

            return decryptDoc;
        }

        #region 扩展

        ///// <summary>
        ///// 根据当前的RequestMessage创建指定类型的ResponseMessage
        ///// </summary>
        ///// <typeparam name="TR">基于ResponseMessageBase的响应消息类型</typeparam>
        ///// <returns></returns>
        //public ResponseMessageText CreateResponseMessage<TR>(string content) where TR : ResponseMessageText
        //{
        //    if (RequestMessage == null)
        //    {
        //        return null;
        //    }

        //    var responseMessage = RequestMessage.CreateResponseMessage<TR>();
        //    responseMessage.Content = content;
        //    return responseMessage;
        //}

        #endregion


        /// <summary>
        /// 执行微信请求
        /// </summary>
        public override void BuildResponseMessage()
        {
            #region NeuChar 执行过程

            #region 添加模拟数据

            //var fakeMessageHandlerNode = new MessageHandlerNode()
            //{
            //    Name = "MessageHandlerNode",
            //};

            //fakeMessageHandlerNode.Config.MessagePair.Add(new MessagePair()
            //{
            //    Request = new Request
            //    {
            //        Type = RequestMsgType.Text,
            //        Keywords = new List<string>() { "nc", "neuchar" }
            //    },
            //    Response = new Response() { Type = ResponseMsgType.Text, Content = "这条消息来自NeuChar\r\n\r\n当前时间：{now}" }
            //});

            //fakeMessageHandlerNode.Config.MessagePair.Add(new MessagePair()
            //{
            //    Request = new Request
            //    {
            //        Type = RequestMsgType.Text,
            //        Keywords = new List<string>() { "senparc", "s" }
            //    },
            //    Response = new Response() { Type = ResponseMsgType.Text, Content = "这条消息同样来自NeuChar\r\n\r\n当前时间：{now}" }
            //});

            //neuralSystem.Root.SetChildNode(fakeMessageHandlerNode);//TODO：模拟添加（应当在初始化的时候就添加）

            #endregion

            var weixinAppId = this._postModel == null ? "" : this._postModel.AppId;

            switch (RequestMessage.MsgType)
            {
                case RequestMsgType.Text:
                    {
                        var requestMessage = RequestMessage as RequestMessageText;

                        ResponseMessage = CurrentMessageHandlerNode.Execute(requestMessage, this, weixinAppId) ??
                                            (OnTextOrEventRequest(requestMessage) ?? OnTextRequest(requestMessage));
                    }
                    break;
                case RequestMsgType.Location:
                    ResponseMessage = OnLocationRequest(RequestMessage as RequestMessageLocation);
                    break;
                case RequestMsgType.Image:
                    ResponseMessage = CurrentMessageHandlerNode.Execute(RequestMessage, this, weixinAppId) ??
                                        OnImageRequest(RequestMessage as RequestMessageImage);
                    break;
                case RequestMsgType.Voice:
                    ResponseMessage = OnVoiceRequest(RequestMessage as RequestMessageVoice);
                    break;
                case RequestMsgType.Video:
                    ResponseMessage = OnVideoRequest(RequestMessage as RequestMessageVideo);
                    break;
                case RequestMsgType.Link:
                    ResponseMessage = OnLinkRequest(RequestMessage as RequestMessageLink);
                    break;
                case RequestMsgType.ShortVideo:
                    ResponseMessage = OnShortVideoRequest(RequestMessage as RequestMessageShortVideo);
                    break;
                case RequestMsgType.File:
                    ResponseMessage = OnFileRequest(RequestMessage as RequestMessageFile);
                    break;
                case RequestMsgType.NeuChar:
                    ResponseMessage = OnNeuCharRequest(RequestMessage as RequestMessageNeuChar);
                    break;
                case RequestMsgType.Unknown:
                    ResponseMessage = OnUnknownTypeRequest(RequestMessage as RequestMessageUnknownType);
                    break;
                case RequestMsgType.Event:
                    {
                        var requestMessageText = (RequestMessage as IRequestMessageEventBase).ConvertToRequestMessageText();
                        ResponseMessage = CurrentMessageHandlerNode.Execute(RequestMessage, this, weixinAppId) ??
                                            OnTextOrEventRequest(requestMessageText) ??
                                                OnEventRequest(RequestMessage as IRequestMessageEventBase);
                    }
                    break;
                default:
                    throw new UnknownRequestMsgTypeException("未知的MsgType请求类型", null);
            }

            #endregion
        }

        /// <summary>
        /// OnExecuting
        /// </summary>
        public override void OnExecuting()
        {
            /* 
             * 此处原消息去重逻辑已经转移到 Init() 方法中。
             * 原因是插入RequestMessage过程发生在Init中，从Init执行到此处的时间内，
             * 如果有新消息加入，将导致去重算法失效。
             * （当然这样情况发生的概率极低，一般只在测试中会发生，
             * 为了确保各种测试环境下的可靠性，作此修改。  —— Jeffrey Su 2018.1.23
             */

            if (CancelExcute)
            {
                return;
            }

            base.OnExecuting();

            //判断是否已经接入开发者信息
            if (DeveloperInfo != null || CurrentMessageContext.AppStoreState == AppStoreState.Enter)
            {
                //优先请求云端应用商店资源

            }
        }

        public override void OnExecuted()
        {
            base.OnExecuted();
        }

    }
}