package message

import (
	"bytes"
	"encoding/binary"
	"fmt"
	"strings"
)

// CanetFrame USR-CANET200_V1.0.7 设备  以太网-CAN 透传协议帧(12字节)
type BtmHeadFrame struct {
	CanLen  byte       //CAN帧数据长度[0,8]，CanData中有效数据字节数
	CanId   CanFrameId //CAN帧ID
	CanData []byte     //CAN帧数据，8字节

}

func NewBtmHeadFrame(buf []byte) *BtmHeadFrame {
	cf := &BtmHeadFrame{}
	cf.Decode(buf)
	return cf
}
func (p *BtmHeadFrame) Encode() []byte {
	buf := make([]byte, 0)
	//CAN 帧ID
	frameId := uint32(p.CanId.ID1)<<21 | uint32(p.CanId.ID2)<<13 | uint32(p.CanId.ID3)<<5 | uint32(p.CanId.ID4)
	buf = binary.BigEndian.AppendUint32(buf, frameId)
	//CAN 帧数据
	if len(p.CanData) != 8 {
		panic(fmt.Sprintf("len(p.CanData)!=8 datalen:%v", len(p.CanData)))
	}
	buf = append(buf, p.CanData...)
	return buf
}

func (p *BtmHeadFrame) Decode(buf []byte) {
	bb := bytes.NewBuffer(buf)
	var idSource uint32
	binary.Read(bb, binary.BigEndian, &idSource)
	data := make([]byte, bb.Len())
	_, err := bb.Read(data)
	if err != nil {
		fmt.Println(err)
		return
	}
	b1 := byte((idSource >> 21) & 0xFF)
	b2 := byte((idSource >> 13) & 0xFF)
	b3 := byte((idSource >> 5) & 0xFF)
	b4 := byte(idSource & 0x1F)

	p.CanId.ID1 = b1
	p.CanId.ID2 = b2
	p.CanId.ID3 = b3
	p.CanId.ID4 = b4
	p.CanData = data
}

func (p *BtmHeadFrame) String() string {
	sb := strings.Builder{}
	sb.WriteString(fmt.Sprintf("CanetFrame CanLen = %d, ID1 = 0x%0x, ID2 = 0x%0x, ID3 = 0x%0x, ID4 = 0x%0x", p.CanLen,
		p.CanId.ID1, p.CanId.ID2, p.CanId.ID3, p.CanId.ID4))
	sb.WriteString("CanData = ")
	for _, d := range p.CanData {
		sb.WriteString(fmt.Sprintf(" 0x%0x ", d))
	}
	return sb.String()
}