using JT808.Protocol.Attributes;
using JT808.Protocol.Enums;
using JT808.Protocol.Exceptions;
using JT808.Protocol.Extensions;
using JT808.Protocol.Formatters;
using JT808.Protocol.MessagePack;
using System;

namespace JT808.Protocol
{
    /// <summary>
    /// JT808数据包
    /// </summary>
    public class JT808Package:IJT808MessagePackFormatter<JT808Package>
    {
        /// <summary>
        /// 起始符
        /// </summary>
        public const byte BeginFlag = 0x7e;
        /// <summary>
        /// 终止符
        /// </summary>
        public const byte EndFlag = 0x7e;
        /// <summary>
        /// 起始符
        /// </summary>
        public byte Begin { get; set; } = BeginFlag;
        /// <summary>
        /// 头数据
        /// </summary>
        public JT808Header Header { get; set; }
        /// <summary>
        /// 数据体
        /// </summary>
        public JT808Bodies Bodies { get; set; }
        /// <summary>
        /// 校验码
        /// 从消息头开始，同后一字节异或，直到校验码前一个字节，占用一个字节。
        /// </summary>
        public byte CheckCode { get; set; }
        /// <summary>
        /// 终止符
        /// </summary>
        public byte End { get; set; } = EndFlag;
        /// <summary>
        /// 808版本号
        /// </summary>
        public JT808Version Version
        {
            get
            {
                if (Header != null)
                {
                    try
                    {
                        if (Header.MessageBodyProperty.VersionFlag)
                        {
                            return JT808Version.JTT2019;
                        }
                        else
                        {
                            return JT808Version.JTT2013;
                        }
                    }
                    catch
                    {
                        return JT808Version.JTT2013;
                    }
                }
                else
                {
                    return JT808Version.JTT2013;
                }
            }
        }

        public JT808Package Deserialize(ref JT808MessagePackReader reader, IJT808Config config)
        {
            // 1. 验证校验和
            if (!config.SkipCRCCode)
            {
                if (!reader.CheckXorCodeVali)
                {
                    throw new JT808Exception(JT808ErrorCode.CheckCodeNotEqual, $"{reader.RealCheckXorCode}!={reader.CalculateCheckXorCode}");
                }
            }
            JT808Package jT808Package = new JT808Package();
            // ---------------开始解包--------------
            // 2.读取起始位置        
            jT808Package.Begin = reader.ReadStart();
            // 3.读取头部信息
            jT808Package.Header = new JT808Header();
            //  3.1.读取消息Id
            jT808Package.Header.MsgId = reader.ReadUInt16();
            //  3.2.读取消息体属性
            jT808Package.Header.MessageBodyProperty = new JT808HeaderMessageBodyProperty(reader.ReadUInt16());
            if (jT808Package.Header.MessageBodyProperty.VersionFlag)
            {
                //2019版本
                jT808Package.Header.ProtocolVersion = reader.ReadByte();
                //  3.4.读取终端手机号 
                jT808Package.Header.TerminalPhoneNo = reader.ReadBCD(20, config.Trim);
                reader.Version = JT808Version.JTT2019;
            }
            else
            {
                //2013版本
                //  3.3.读取终端手机号 
                jT808Package.Header.TerminalPhoneNo = reader.ReadBCD(config.TerminalPhoneNoLength, config.Trim);
            }
            //  3.4.读取消息流水号
            jT808Package.Header.MsgNum = reader.ReadUInt16();
            //  3.5.判断有无分包
            if (jT808Package.Header.MessageBodyProperty.IsPackage)
            {
                //3.5.1.读取消息包总数
                jT808Package.Header.PackgeCount = reader.ReadUInt16();
                //3.5.2.读取消息包序号
                jT808Package.Header.PackageIndex = reader.ReadUInt16();
            }
            // 4.处理数据体
            //  4.1.判断有无数据体
            if (jT808Package.Header.MessageBodyProperty.DataLength > 0)
            {
                if(config.MsgIdFactory.TryGetValue(jT808Package.Header.MsgId,out object instance))
                {
                    if (jT808Package.Header.MessageBodyProperty.IsPackage)
                    {
                        if (jT808Package.Header.PackageIndex > 1)
                        {
                            try
                            {
                                //4.2处理第二包之后的分包数据消息体
                                JT808SplitPackageBodies jT808SplitPackageBodies = new JT808SplitPackageBodies();
                                jT808Package.Bodies = jT808SplitPackageBodies.Deserialize(ref reader, config);
                            }
                            catch (Exception ex)
                            {
                                throw new JT808Exception(JT808ErrorCode.BodiesParseError, ex);
                            }
                        }
                        else
                        {
                            try
                            {
                                //4.2.处理消息体
                                jT808Package.Bodies = JT808MessagePackFormatterResolverExtensions.JT808DynamicDeserialize(
                                    instance,
                                    ref reader, config);
                            }
                            catch (Exception ex)
                            {
                                throw new JT808Exception(JT808ErrorCode.BodiesParseError, ex);
                            }
                        }
                    }
                    else
                    {
                        try
                        {
                            //4.2.处理消息体
                            jT808Package.Bodies = JT808MessagePackFormatterResolverExtensions.JT808DynamicDeserialize(
                                instance,
                                ref reader, config);
                        }
                        catch (Exception ex)
                        {
                            throw new JT808Exception(JT808ErrorCode.BodiesParseError, ex);
                        }
                    }
                }
            }
 
            // 5.读取校验码
            jT808Package.CheckCode = reader.ReadByte();
            // 6.读取终止位置
            jT808Package.End = reader.ReadEnd();
            // ---------------解包完成--------------
            return jT808Package;
        }

        public void Serialize(ref JT808MessagePackWriter writer, JT808Package value, IJT808Config config)
        {
            // ---------------开始组包--------------
            // 1.起始符
            writer.WriteStart();
            // 2.写入头部 //部分有带数据体的长度，那么先跳过写入头部部分
            //  2.1.消息ID
            writer.WriteUInt16(value.Header.MsgId);
            //  2.2.消息体属性(包含消息体长度所以先跳过)
            writer.Skip(2, out int msgBodiesPropertyPosition);
            if (value.Header.MessageBodyProperty.VersionFlag)
            {
                //2019版本
                //  2.3.协议版本号
                writer.WriteByte(value.Header.ProtocolVersion);
                //  2.4.终端手机号
                writer.WriteBCD(value.Header.TerminalPhoneNo, 20);
                writer.Version = JT808Version.JTT2019;
            }
            else
            {
                //2013版本
                //  2.3.终端手机号 (写死大陆手机号码)
                writer.WriteBCD(value.Header.TerminalPhoneNo, config.TerminalPhoneNoLength);
            }
            value.Header.MsgNum = value.Header.MsgNum > 0 ? value.Header.MsgNum : config.MsgSNDistributed.Increment();
            //  2.4.消息流水号
            writer.WriteUInt16(value.Header.MsgNum);
            //  2.5.判断是否分包
            if (value.Header.MessageBodyProperty.IsPackage)
            {
                // 2.5.1.消息包总数
                writer.WriteUInt16(value.Header.PackgeCount);
                // 2.5.2.消息包序号
                writer.WriteUInt16(value.Header.PackageIndex);
            }
            int headerLength = writer.GetCurrentPosition();
            // 3.处理数据体部分
            if (value.Bodies != null)
            {
                if (!value.Bodies.SkipSerialization)
                {
                    JT808MessagePackFormatterResolverExtensions.JT808DynamicSerialize(value.Bodies,
                        ref writer, value.Bodies,
                        config);
                }
            }
            //  3.1.处理数据体长度
            // 2.2.回写消息体属性
            value.Header.MessageBodyProperty.DataLength = (writer.GetCurrentPosition() - headerLength);
            writer.WriteUInt16Return(value.Header.MessageBodyProperty.Wrap(), msgBodiesPropertyPosition);
            // 4.校验码
            writer.WriteXor();
            // 5.终止符
            writer.WriteEnd();
            // 6.编码
            writer.WriteEncode();
            // ---------------组包结束--------------
        }
    }
}