using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using NewLife.Collections;
using NewLife.Data;
using NewLife.Messaging;
using NewLife.Reflection;
using NewLife.Remoting;
using NewLife.Serialization;

namespace NewLife.Http
{
    /// <summary>Http编码器</summary>
    public class HttpEncoder : EncoderBase, IEncoder
    {
        #region 属性
        /// <summary>是否使用Http状态。默认false，使用json包装响应码</summary>
        public Boolean UseHttpStatus { get; set; }
        #endregion

        /// <summary>编码</summary>
        /// <param name="action"></param>
        /// <param name="code"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public virtual Packet Encode(String action, Int32 code, Object value)
        {
            //if (value == null) return null;

            if (value is Packet pk) return pk;
            if (value is IAccessor acc) return acc.ToPacket();

            // 不支持序列化异常
            if (value is Exception ex) value = ex.GetTrue()?.Message;

            String json;
            if (UseHttpStatus)
                json = value.ToJson(false, false, false);
            else
                json = new { action, code, data = value }.ToJson(false, true, false);
            WriteLog("{0}=>{1}", action, json);

            return json.GetBytes();
        }

        /// <summary>解码参数</summary>
        /// <param name="action"></param>
        /// <param name="data"></param>
        /// <param name="msg"></param>
        /// <returns></returns>
        public virtual IDictionary<String, Object> DecodeParameters(String action, Packet data, IMessage msg)
        {
            /*
             * 数据内容解析需要根据http数据类型来判定使用什么格式处理
             * **/

            var str = data.ToStr();
            WriteLog("{0}<={1}", action, str);
            if (str.IsNullOrEmpty()) return null;

            var ctype = Array.Empty<String>();
            if (msg is HttpMessage hmsg && str[0] == '{')
            {
                if (hmsg.ParseHeaders()) ctype = (hmsg.Headers["Content-type"] + "").Split(';');
            }

            if (ctype.Contains("application/json"))
            {
                var dic = new JsonParser(str).Decode().ToDictionary();
                var rs = new Dictionary<String, Object>(StringComparer.OrdinalIgnoreCase);
                foreach (var item in dic)
                {
                    if (item.Value is String str2)
                        rs[item.Key] = HttpUtility.UrlDecode(str2);
                    else
                        rs[item.Key] = item.Value;
                }

                return rs;
            }
            else
            {
                var dic = str.SplitAsDictionary("=", "&");
                var rs = new Dictionary<String, Object>(StringComparer.OrdinalIgnoreCase);
                foreach (var item in dic)
                {
                    rs[item.Key] = HttpUtility.UrlDecode(item.Value);
                }
                return rs;
            }
        }

        /// <summary>解码结果</summary>
        /// <param name="action"></param>
        /// <param name="data"></param>
        /// <param name="msg">消息</param>
        /// <returns></returns>
        public virtual Object DecodeResult(String action, Packet data, IMessage msg)
        {
            var json = data.ToStr();
            WriteLog("{0}<={1}", action, json);

            return new JsonParser(json).Decode();
        }

        /// <summary>转换为目标类型</summary>
        /// <param name="obj"></param>
        /// <param name="targetType"></param>
        /// <returns></returns>
        public virtual Object Convert(Object obj, Type targetType) => JsonHelper.Default.Convert(obj, targetType);

        #region 编码/解码
        /// <summary>创建请求</summary>
        /// <param name="action"></param>
        /// <param name="args"></param>
        /// <returns></returns>
        public virtual IMessage CreateRequest(String action, Object args)
        {
            // 请求方法 GET / HTTP/1.1
            var req = new HttpMessage();
            var sb = Pool.StringBuilder.Get();
            sb.Append("GET ");
            sb.Append(action);

            // 准备参数，二进制优先
            if (args is Packet pk)
            {
            }
            // 支持IAccessor
            else if (args is IAccessor acc)
                pk = acc.ToPacket();
            else if (args is Byte[] buf)
                pk = new Packet(buf);
            else
            {
                pk = null;

                // url参数
                sb.Append('?');
                if (args.GetType().GetTypeCode() != TypeCode.Object)
                {
                    sb.Append(args);
                }
                else
                {
                    foreach (var item in args.ToDictionary())
                    {
                        sb.AppendFormat("{0}={1}", item.Key, item.Value);
                    }
                }
            }
            sb.AppendLine(" HTTP/1.1");

            if (pk != null && pk.Total > 0)
            {
                sb.AppendFormat("Content-Length:{0}\r\n", pk.Total);
                sb.AppendLine("Content-Type:application/json");
            }
            sb.Append("Connection:keep-alive");

            req.Header = sb.Put(true).GetBytes();

            return req;
        }

        /// <summary>创建响应</summary>
        /// <param name="msg"></param>
        /// <param name="action"></param>
        /// <param name="code"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public virtual IMessage CreateResponse(IMessage msg, String action, Int32 code, Object value)
        {
            if (code <= 0 && UseHttpStatus) code = 200;

            // 编码响应数据包，二进制优先
            var pk = Encode(action, code, value);

            // 构造响应消息
            var rs = new HttpMessage
            {
                Payload = pk
            };
            if (code >= 500) rs.Error = true;

            // HTTP/1.1 502 Bad Gateway
            var sb = Pool.StringBuilder.Get();
            sb.Append("HTTP/1.1 ");

            if (UseHttpStatus)
            {
                sb.Append(code);
                if (code < 500)
                    sb.AppendLine(" OK");
                else
                    sb.AppendLine(" Error");
            }
            else
            {
                sb.AppendLine("200 OK");
            }

            sb.AppendFormat("Content-Length:{0}\r\n", pk?.Total ?? 0);
            sb.AppendLine("Content-Type:application/json");
            sb.Append("Connection:keep-alive");

            rs.Header = sb.Put(true).GetBytes();

            return rs;
        }

        /// <summary>解码 请求/响应</summary>
        /// <param name="msg">消息</param>
        /// <param name="action">服务动作</param>
        /// <param name="code">错误码</param>
        /// <param name="value">参数或结果</param>
        /// <returns></returns>
        public override Boolean Decode(IMessage msg, out String action, out Int32 code, out Packet value)
        {
            action = null;
            code = 0;
            value = null;

            if (msg is not HttpMessage http) return false;

            // 分析请求方法 GET / HTTP/1.1
            var p = http.Header.IndexOf(new[] { (Byte)'\r', (Byte)'\n' });
            if (p <= 0) return false;

            var line = http.Header.ToStr(null, 0, p);

            var ss = line.Split(' ');
            if (ss.Length < 3) return false;

            // 第二段是地址
            var url = ss[1];
            p = url.IndexOf('?');
            if (p > 0)
            {
                action = url[1..p];
                value = url[(p + 1)..].GetBytes();
            }
            else
            {
                action = url[1..];
                value = http.Payload;
            }

            return true;
        }
        #endregion
    }
}