package sl500_api

import (
	"bytes"
	"encoding/binary"
	"errors"
	"fmt"
	"time"

	"github.com/tarm/serial"
)

var Baud = baudRegistry()

func baudRegistry() *baudList {
	return &baudList{
		Baud4800:   baud{0, 4800},
		Baud9600:   baud{1, 9600},
		Baud14400:  baud{2, 14400},
		Baud19200:  baud{3, 19200},
		Baud28800:  baud{4, 28800},
		Baud38400:  baud{5, 38400},
		Baud57600:  baud{6, 57600},
		Baud115200: baud{7, 115200},
	}
}

const (
	Type_A       = byte(0xA)
	Type_B       = byte(0xB)
	Type_ISO     = byte(0x1)
	AntennaOn    = byte(0x1)
	AntennaOff   = byte(0x0)
	ColorOff     = byte(0x0)
	ColorRed     = byte(0x1)
	ColorGreen   = byte(0x2)
	ColorYellow  = byte(0x3)
	RequestStd   = byte(0x26)
	RequestAll   = byte(0x52)
	AuthModeKeyA = byte(0x60)
	AuthModeKeyB = byte(0x61)
)

type baudList struct {
	Baud4800   baud
	Baud9600   baud
	Baud14400  baud
	Baud19200  baud
	Baud28800  baud
	Baud38400  baud
	Baud57600  baud
	Baud115200 baud
}

type baud struct {
	ByteValue byte
	IntValue  int
}

type Sl500 struct {
	config  *serial.Config
	port    *serial.Port
	logging bool
	open    bool
}

type response struct {
	data []byte
	err  error
}

func NewConnection(path string, baud baud, logging bool) (Sl500, error) {
	c := &serial.Config{Name: path, Baud: baud.IntValue, ReadTimeout: 100 * time.Millisecond}
	o, err := serial.OpenPort(c)

	res := Sl500{}

	if err != nil {
		return res, err
	}

	res.config = c
	res.port = o
	res.logging = logging
	res.open = true

	return res, nil
}

func (s *Sl500) Open() error {
	if s.open {
		return errors.New("port already opened")
	}

	p, err := serial.OpenPort(s.config)

	if err != nil {
		return err
	}

	s.port = p
	s.open = true

	return nil
}

func (s *Sl500) Close() error {
	if s.port == nil || !s.open {
		return errors.New("port not opened")
	}

	err := s.port.Close()
	s.open = false

	return err
}

func (s *Sl500) RfInitCom(baud byte) ([]byte, error) {
	err := sendRequest(s, 0x0101, []byte{baud})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfInitDeviceNumber(deviceId []byte) ([]byte, error) {
	err := sendRequest(s, 0x0201, deviceId)

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfGetDeviceNumber() ([]byte, error) {
	err := sendRequest(s, 0x0301, []byte{})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfGetModel() ([]byte, error) {
	err := sendRequest(s, 0x0401, []byte{})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfAntennaSta(antennaState byte) ([]byte, error) {
	err := sendRequest(s, 0x0C01, []byte{antennaState})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfInitType(workType byte) ([]byte, error) {
	err := sendRequest(s, 0x0801, []byte{workType})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfBeep(durationMs byte) ([]byte, error) {
	err := sendRequest(s, 0x0601, []byte{durationMs})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfLight(color byte) ([]byte, error) {
	err := sendRequest(s, 0x0701, []byte{color})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfRequest(requestType byte) ([]byte, error) {
	err := sendRequest(s, 0x0102, []byte{requestType})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfAnticoll() ([]byte, error) {
	err := sendRequest(s, 0x0202, []byte{})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfSelect(serialNumber []byte) ([]byte, error) {
	err := sendRequest(s, 0x0302, serialNumber)

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfHalt() ([]byte, error) {
	err := sendRequest(s, 0x0402, []byte{})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfM1Authentication2(authMode byte, blockNumber byte, key []byte) ([]byte, error) {
	err := sendRequest(s, 0x0702, []byte{authMode, blockNumber}, key)

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfM1Read(blockNumber byte) ([]byte, error) {
	err := sendRequest(s, 0x0802, []byte{blockNumber})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfM1Write(blockNumber byte, data []byte) ([]byte, error) {
	err := sendRequest(s, 0x0902, []byte{blockNumber}, data)

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfM1Initval(blockNumber byte, initialValue []byte) ([]byte, error) {
	err := sendRequest(s, 0x0A02, []byte{blockNumber}, initialValue)

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfM1Readval(blockNumber byte) ([]byte, error) {
	err := sendRequest(s, 0x0B02, []byte{blockNumber})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfM1Decrement(blockNumber byte, decrementValue []byte) ([]byte, error) {
	err := sendRequest(s, 0x0C02, []byte{blockNumber}, decrementValue)

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfM1Increment(blockNumber byte, incrementValue []byte) ([]byte, error) {
	err := sendRequest(s, 0x0D02, []byte{blockNumber}, incrementValue)

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfM1Restore(blockNumber byte) ([]byte, error) {
	err := sendRequest(s, 0x0E02, []byte{blockNumber})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func (s *Sl500) RfM1Transfer(blockNumber byte) ([]byte, error) {
	err := sendRequest(s, 0x0F02, []byte{blockNumber})

	if err != nil {
		return nil, err
	}

	return readResponseWithTimeout(s)
}

func readResponseWithTimeout(s *Sl500) ([]byte, error) {
	inner := make(chan response)

	go func() {
		i, v := readResponse(s)
		inner <- response{data: i, err: v}
	}()

	v := <-inner

	return v.data, v.err
}

func readResponse(s *Sl500) ([]byte, error) {
	var buf []byte
	innerBuf := make([]byte, 128)

	totalRead := 0

	for {
		n, err := s.port.Read(innerBuf)

		if err != nil {
			return nil, err
		}

		totalRead += n
		buf = append(buf, innerBuf[:n]...)

		if totalRead < 3 {
			continue
		}
		if int(buf[2]) != getBufLen(buf)-4 {
			continue
		}

		break
	}

	if buf[0] != 0xAA || buf[1] != 0xBB {
		return nil, fmt.Errorf("Response format invalid")
	}

	if buf[8] != 0x0 {
		return nil, fmt.Errorf("Response status is fail")
	}

	buf = buf[4:]
	ver := byte(0x00)

	for _, k := range buf[:len(buf)-1] {
		ver = ver ^ k
	}

	if ver != buf[len(buf)-1] {
		return nil, fmt.Errorf("Response verification failed")
	}

	buf = filterBuf(buf)
	buf = buf[5 : len(buf)-1]

	if s.logging {
		fmt.Printf("sl500[%v]: <- %X\n", s.config.Name, buf)
	}

	return buf, nil
}

func getBufLen(buf []byte) int {
	l := len(buf)
	for i, b := range buf {
		if i < 2 {
			continue
		}

		if b == 0xAA {
			l--
		}
	}
	return l
}

func filterBuf(buf []byte) []byte {
	result := make([]byte, getBufLen(buf))

	ind := 0
	for i, b := range buf {
		if i > 0 && buf[i-1] == 0xAA && b == 0x00 {
			continue
		}

		result[ind] = b
		ind++
	}
	return result
}

func sendRequest(s *Sl500, commandCode int16, bytesData ...[]byte) error {
	if !s.open {
		return errors.New("serial port is closed")
	}

	buf := new(bytes.Buffer)

	ver := byte(0x00)
	length := 5

	for _, b := range bytesData {
		length += len(b)
	}

	_ = binary.Write(buf, binary.BigEndian, byte(0xAA))
	_ = binary.Write(buf, binary.BigEndian, byte(0xBB))
	_ = binary.Write(buf, binary.BigEndian, byte(length))
	_ = binary.Write(buf, binary.BigEndian, byte(0x00))
	_ = binary.Write(buf, binary.BigEndian, int16(0)) // device id
	_ = binary.Write(buf, binary.BigEndian, commandCode)

	for _, data := range bytesData {
		_ = binary.Write(buf, binary.BigEndian, data)
	}

	for _, k := range buf.Bytes()[3:] {
		ver = ver ^ k
	}
	_ = binary.Write(buf, binary.BigEndian, ver)

	if s.logging {
		fmt.Printf("sl500[%v]: -> %X\n", s.config.Name, buf.Bytes())
	}

	_, err := s.port.Write(buf.Bytes())

	return err
}