package message

import "encoding/binary"

//数据帧（0x80+扩展类型）,一个CAN帧只能存储8个字节，对于一个应答器报文，分片到多个CAN数据帧中

// BtmDataMessageFrame 数据帧-应答器报文
// offset = [0x00,0x0c] 共13个即可用于存储应答器报文的共104个字节
// BtmDataMessageTimeAFrame 数据帧-时间戳A
// offset = 0x0d
// BtmDataMessageTimeBFrame 数据帧-时间戳B
// offset = 0x0e
// BtmDataMessageEndFrame 数据帧-结束
// offset = 0x7f
const (
	DATA_TIME_A_OFFSET = 0x0d
	DATA_TIME_B_OFFSET = 0x0e
	DATA_END_OFFSET    = 0x7f
)

type BtmDataMessageAtpFrame struct {
	//帧ID
	FId CanFrameId
	//8字节,应答器报文片段
	Message []byte
}
type BtmDataMessageAtpTimeAndEndFrame struct {
	//帧ID
	FId CanFrameId
	//时间戳A
	Time uint32
	//CRC
	Crc32 uint32
}

func CreateBtmDataMessageDataAtpFrame(sn byte, offset byte) *BtmDataMessageAtpFrame {
	return &BtmDataMessageAtpFrame{
		FId: *NewCanFrameId(CAN_ADDR_RSP_ATP, CAN_ADDR_RSP_BTM, 0x80+offset, sn),
	}
}

func (f *BtmDataMessageAtpFrame) Encode() *BtmHeadFrame {
	cf := &BtmHeadFrame{}
	cf.CanId = f.FId
	cf.CanLen = 8

	dataBuf := make([]byte, 0, 8)
	for _, data := range f.Message {
		dataBuf = append(dataBuf, data)
	}
	cf.CanData = dataBuf
	return cf
}
func (f *BtmDataMessageAtpFrame) Decode(cf *BtmHeadFrame) bool {
	f.FId = cf.CanId
	//
	reader := NewCanBitsReader(cf.CanData, 8)
	//
	f.Message = make([]byte, 0, 8)
	for c := 0; c < 8; c++ {
		data, ok := reader.ReadByte()
		if !ok {
			return false
		}
		f.Message = append(f.Message, data)
	}
	//
	return true
}

/////////////////////////////////////////////////////

func (atp *BtmDataMessageAtpTimeAndEndFrame) Encode() *BtmHeadFrame {
	cf := &BtmHeadFrame{}
	cf.CanId = atp.FId
	cf.CanLen = 8
	data := make([]byte, 0)
	data = binary.BigEndian.AppendUint32(data, atp.Time)
	data = binary.BigEndian.AppendUint32(data, atp.Crc32)
	cf.CanData = data
	return cf
}

func CreateBtmDataMessageTimeAtpFrame(sn byte, offset byte) *BtmDataMessageAtpTimeAndEndFrame {
	return &BtmDataMessageAtpTimeAndEndFrame{FId: *NewCanFrameId(CAN_ADDR_RSP_ATP, CAN_ADDR_RSP_BTM, 0x80+offset, sn)}
}

////////////////////////////////////////////////////////////

func BtmDataMessageEndAtpFrame(sn byte) *BtmDataMessageAtpTimeAndEndFrame {
	return &BtmDataMessageAtpTimeAndEndFrame{
		FId: *NewCanFrameId(CAN_ADDR_RSP_ATP, CAN_ADDR_RSP_BTM, 0xff, sn),
	}
}