// Package route
// @Author: Wang Feng
// @Description:
// @Version: 0.1.0
// @Date: 2022/5/5 20:41
// @Copyright: MIN-Group；国家重大科技基础设施——未来网络北大实验室；深圳市信息论与未来网络重点实验室
//

package route

import (
	"minlib/component"
	"minlib/encoding"
	"mlsr/extensions"
)

//
//  RoutingTableEntry
//  @Description: 路由表条目
//
type RoutingTableEntry struct {
	m_destination *component.Identifier
	NextHopList
}

//
//  ToString
//  @Description: 转string。用于测试
//  @receiver e
//  @return string
//
func (e *RoutingTableEntry) ToString() string {
	res := ""
	res += "目的路由器: " + e.m_destination.ToUri() + "\n"
	res += e.NextHopList.ToString()
	return res
}

//
//  NewRoutingTableEntry
//  @Description: 新建一个路由表条目
//  @param dest
//  @return *RoutingTableEntry
//  @return error
//
func NewRoutingTableEntry(dest *component.Identifier) (*RoutingTableEntry, error) {
	// todo: 判断dest是否格式有效
	rte := new(RoutingTableEntry)
	rte.m_destination = dest
	return rte, nil
}

//
//  GetDestination
//  @Description: 获取目的路由器
//  @receiver e
//  @return *component.Identifier
//
func (e *RoutingTableEntry) GetDestination() *component.Identifier {
	return e.m_destination
}

//
//  SetDestination
//  @Description: 设置目的路由器
//  @receiver e
//  @param dest
//
func (e *RoutingTableEntry) SetDestination(dest *component.Identifier) {
	e.m_destination = dest
}

//
//  WireEncode
//  @Description: 线速编码
//  @receiver l
//  @param encoder
//  @return int
//  @return error
//
func (e *RoutingTableEntry) WireEncode(encoder *encoding.Encoder) (int, error) {
	totalLength := 0
	// TLV-Value
	tmpLen, err := e.NextHopList.WireEncode(encoder)
	if err != nil {
		return 0, err
	}
	totalLength += tmpLen
	tmpLen, err = e.m_destination.WireEncode(encoder)
	if err != nil {
		return 0, err
	}
	totalLength += tmpLen

	// TLV-Length
	tmpLen, err = encoder.PrependVarNumber(encoding.VlInt(totalLength))
	if err != nil {
		return 0, err
	}
	totalLength += tmpLen

	// TLV-Type
	tmpLen, err = encoder.PrependVarNumber(extensions.TlvMlsrRoutingTableEntry)
	if err != nil {
		return 0, err
	}
	totalLength += tmpLen

	return totalLength, nil
}

//
//  WireDecode
//  @Description: 线速解码
//  @receiver l
//  @param block
//  @return error
//
func (e *RoutingTableEntry) WireDecode(block *encoding.Block) error {
	// 检查 TLV-TYPE 是否正确
	if err := encoding.ExpectType(block.GetType(), extensions.TlvMlsrRoutingTableEntry); err != nil {
		return err
	}

	// 首先解析子Block
	if err := block.ParseSubElements(); err != nil {
		return err
	}

	// 提取参数
	for _, parameter := range block.GetSubElements() {
		switch parameter.GetType() {
		case encoding.TlvIdentifier:
			iden := component.Identifier{}
			if err := iden.WireDecode(parameter); err != nil {
				return err
			}
			e.m_destination = &iden
		case extensions.TlvMlsrNextHopList:
			if err := e.NextHopList.WireDecode(parameter); err != nil {
				return err
			}
		}
	}
	return nil
}