package message

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

// CanetFrame USR-CANET200_V1.0.7 设备  以太网-CAN 透传协议帧(13字节)
type CanetFrame struct {
	FF           bool       //true-1扩展帧
	RTR          bool       //true-1远程帧
	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
	IsTrainPcSim bool       //是否列车pc仿真
}

func NewCanetFrame(buf []byte, isTrainPcSim bool) *CanetFrame {
	cf := &CanetFrame{IsTrainPcSim: isTrainPcSim}
	cf.Decode(buf)
	return cf
}

func NewCanetFrame2(buf []byte, isTrainPcSim bool) *CanetFrame {
	cf := &CanetFrame{IsTrainPcSim: isTrainPcSim}
	cf.Decode2(buf)
	return cf
}
func (p *CanetFrame) Encode2() []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("len(p.CanData)!=8")
	}
	buf = append(buf, p.CanData...)
	return buf
}

func (p *CanetFrame) Encode() []byte {
	buf := make([]byte, 0)
	if !p.IsTrainPcSim {
		//canet200帧信息
		b1 := byte(0x00)
		if p.FF {
			b1 |= 0x80 //bit7
		}
		if p.RTR {
			b1 |= 0x40 //bit6
		}
		b1 |= p.CanLen & 0x0f
		buf = append(buf, b1)
	}
	//CAN 帧ID
	buf = append(buf, p.CanId.ID1)
	buf = append(buf, p.CanId.ID2)
	buf = append(buf, p.CanId.ID3)
	if p.IsTrainPcSim {
		buf = append(buf, p.CanId.ID4)
	} else {
		buf = append(buf, p.CanId.ID4<<3)
	}

	//CAN 帧数据
	if len(p.CanData) != 8 {
		panic("len(p.CanData)!=8")
	}
	buf = append(buf, p.CanData...)
	return buf
}
func (p *CanetFrame) Decode2(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)
	b2 := byte((idSource << 7) >> 13)
	b3 := byte((idSource << 15) >> 20)
	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 *CanetFrame) Decode(buf []byte) {
	if len(buf) != 13 {
		panic("len(buf)!=13")
	}
	p.FF = buf[0]&0x80 == 0x80
	p.RTR = buf[0]&0x40 == 0x40
	p.CanLen = buf[0] & 0x0f
	//1 2 3 4
	p.CanId.ID1 = buf[1]
	p.CanId.ID2 = buf[2]
	p.CanId.ID3 = buf[3]
	p.CanId.ID4 = buf[4] >> 3
	//
	p.CanData = buf[5:]
}
func (p *CanetFrame) String() string {
	sb := strings.Builder{}
	sb.WriteString(fmt.Sprintf("CanetFrame FF = %t, RTR = %t, CanLen = %d, ID1 = 0x%0x, ID2 = 0x%0x, ID3 = 0x%0x, ID4 = 0x%0x, isTrainPcSim=%v", p.FF, p.RTR, p.CanLen,
		p.CanId.ID1, p.CanId.ID2, p.CanId.ID3, p.CanId.ID4, p.IsTrainPcSim))
	sb.WriteString("CanData = ")
	for _, d := range p.CanData {
		sb.WriteString(fmt.Sprintf(" 0x%0x ", d))
	}
	return sb.String()
}

// CanFrameType 获取canet帧类型
func (p *CanetFrame) CanFrameType() CanFrameType {
	switch p.CanId.ID3 {
	case 0x01:
		{ //状态应答帧0x01
			return CfStatusRsp
		}
	case 0x8d:
		{ //msgTimeA数据帧0x80+0x0d
			return CfMsgTimeA
		}
	case 0x8e:
		{ //msgTimeB数据帧0x80+0x0e
			return CfMsgTimeB
		}
	case 0xff:
		{ //msgEnd数据帧0x80+0x7f
			return CfMsgEnd
		}
	case 0x02:
		{
			if p.CanId.ID1 == 0x62 && p.CanId.ID2 == 0x81 {
				return CfReq
			} else {
				return CfTimeSync
			}
		}
	default:
		if p.CanId.ID3 >= 0x80 && p.CanId.ID3 <= 0x8c { //数据帧0x80+(0x00-0x0c)
			return CfMsg
		} else {
			slog.Warn(fmt.Sprintf("无法识别的Canet帧[%s]", p.String()))
			return CfNon
		}
	}
}

// CanFrameType 帧类型定义
type CanFrameType = byte

// Can帧类型枚举
const (
	CfNon       = CanFrameType(0)
	CfReq       = CanFrameType(1) //查询帧0x02
	CfStatusRsp = CanFrameType(2) //状态应答帧0x01
	CfTimeSync  = CanFrameType(3) //时间同步校验帧0x02
	CfMsg       = CanFrameType(4) //数据帧0x80+(0x00-0x0c)
	CfMsgTimeA  = CanFrameType(5) //msgTimeA数据帧0x80+0x0d
	CfMsgTimeB  = CanFrameType(6) //msgTimeB数据帧0x80+0x0e
	CfMsgEnd    = CanFrameType(7) //msgEnd数据帧0x80+0x7f
)