package Receivers

import (
	"gitee.com/ling-bin/network/netConn"

	"errors"
)

//策略分包器
type DynamicReceiver struct {
	CurrentReceiver netConn.IReceiver   //当前分包器
	Receivers       []netConn.IReceiver //分包器集合
	IsPackStart     bool                //是否开始分包
	IsSingle        bool                //是否只有一个分包算法
}

//策略分包器
func NewDynamicReceiver () *DynamicReceiver {
	return  &DynamicReceiver{
		IsPackStart: false,
		Receivers:   nil,
	}
}

//分包处理
func (d *DynamicReceiver) Receiver(conn netConn.IConnection, buffer []byte, offset int, count int) (err error) {
	var newBuf []byte
	cacheBf := conn.GetBytesCache()
	if cacheBf.Len() > 0{
		cacheBf.Write(buffer[offset:count])
		newBuf = cacheBf.Bytes()
		cacheBf.Reset()
	} else {
		newBuf = buffer[offset:count]
	}
	//fmt.Printf( "[策略缓存]=======:%p\n", newBuf)
	for {
		if d.IsPackStart {
			iReceiver := d.selectReceiver(conn, newBuf)
			if iReceiver == nil {
				//到最后一个字节还未找到分包算法
				if len(newBuf) == 1{
					break
				}
				//未找到分包器跳过当前字节
				newBuf = newBuf[1:]
				continue
			}
			d.CurrentReceiver = iReceiver
			d.IsPackStart = false
		}
		bytes, handleCount, isPackEnd := d.CurrentReceiver.Receiver(conn, newBuf)
		//是否分包结束
		if isPackEnd {
			d.IsPackStart = true
		}
		bufLen := len(bytes)
		if bytes == nil || bufLen == 0 {
			break
		}
		//处理数
		if handleCount == 0 {
			if bufLen != 0 {
				if conn.GetBytesCache().Len() > 65535 {
					conn.Stop()
					return errors.New("设备上传数据过大！")
				}
				conn.GetBytesCache().Write(bytes)
			}
			break
		}
		newBuf = bytes
		//fmt.Printf( "[策略缓存]=======:%p\n", newBuf)
	}
	return nil
}

//选择分包器
func (d *DynamicReceiver) selectReceiver(conn netConn.IConnection, buffer []byte) netConn.IReceiver {
	//单个分包算法直接跳过认包逻辑
	if d.IsSingle {
		isMe := d.Receivers[0].IsMeHandle(conn, buffer)
		if isMe {
			return d.Receivers[0]
		}
		return nil
	}
	for i := 0; i < len(d.Receivers); i++ {
		isMe := d.Receivers[i].IsMeHandle(conn, buffer)
		if isMe {
			return d.Receivers[i]
		}
	}
	return nil
}