using System;
using System.Collections.Generic;
using System.IO;
using NewLife.Collections;
using NewLife.Data;

namespace NewLife.Http
{
    /// <summary>Http请求响应基类</summary>
    public abstract class HttpBase
    {
        #region 属性
        /// <summary>内容长度</summary>
        public Int32 ContentLength { get; set; }

        /// <summary>内容类型</summary>
        public String ContentType { get; set; }

        /// <summary>头部集合</summary>
        public IDictionary<String, Object> Headers { get; set; } = new NullableDictionary<String, Object>(StringComparer.OrdinalIgnoreCase);

        /// <summary>获取/设置 头部</summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public String this[String key] { get { return Headers[key] + ""; } set { Headers[key] = value; } }
        #endregion

        #region 解析
        /// <summary>过期时间</summary>
        internal DateTime Expire { get; set; }

        /// <summary>是否已完整</summary>
        internal Boolean IsCompleted => ContentLength == 0 || ContentLength <= BodyLength;

        /// <summary>主体长度</summary>
        internal Int32 BodyLength { get; set; }

        private static Byte[] NewLine = new[] { (Byte)'\r', (Byte)'\n', (Byte)'\r', (Byte)'\n' };
        internal Boolean ParseHeader(Packet pk)
        {
            var p = pk.IndexOf(NewLine);
            if (p < 0) return false;

            var str = pk.ReadBytes(0, p).ToStr();
#if DEBUG
            Log.XTrace.WriteLine(str);
#endif

            // 截取
            var lines = str.Split("\r\n");
            // 重构
            p += 4;
            pk.Set(pk.Data, pk.Offset + p, pk.Count - p);

            // 分析头部
            //headers.Clear();
            var line = lines[0];
            for (var i = 1; i < lines.Length; i++)
            {
                line = lines[i];
                p = line.IndexOf(':');
                if (p > 0) Headers[line.Substring(0, p)] = line.Substring(p + 1).Trim();
            }

            ContentLength = Headers["Content-Length"].ToInt();
            ContentType = Headers["Content-Type"] + "";

            // 分析第一行
            if (!OnParse(lines[0])) return false;

            //// 判断主体长度
            //BodyLength += pk.Count;
            //if (ContentLength > 0 && BodyLength >= ContentLength) IsCompleted = true;

            return true;
        }

        /// <summary>分析第一行</summary>
        /// <param name="firstLine"></param>
        protected abstract Boolean OnParse(String firstLine);

        private MemoryStream _cache;
        internal Boolean ParseBody(ref Packet pk)
        {
            BodyLength += pk.Count;

            if (_cache == null) _cache = new MemoryStream();
            pk.CopyTo(_cache);

            if (!IsCompleted) return false;

            pk = _cache.ToArray();
            _cache = null;

            return true;
        }
        #endregion

        #region 读写
        /// <summary>创建请求响应包</summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public Packet Build(Packet data)
        {
            var len = data != null ? data.Count : 0;

            var rs = new Packet(BuildHeader(len).GetBytes())
            {
                Next = data
            };

            return rs;
        }

        /// <summary>创建头部</summary>
        /// <param name="length"></param>
        /// <returns></returns>
        protected abstract String BuildHeader(Int32 length);
        #endregion
    }
}