package main

import (
	"fmt"
	"math"
	"time"
)

const civAddress = 0xa4
const sReadInterval = time.Second

type civOperatingMode struct {
	name string
	code byte
}

var civOperatingModes = []civOperatingMode{
	{name: "LSB", code: 0x00},
	{name: "USB", code: 0x01},
	{name: "AM", code: 0x02},
	{name: "CW", code: 0x03},
	{name: "RTTY", code: 0x04},
	{name: "FM", code: 0x05},
	{name: "WFM", code: 0x06},
	{name: "CW-R", code: 0x07},
	{name: "RTTY-R", code: 0x08},
	{name: "DV", code: 0x17},
}

type civFilter struct {
	name string
	code byte
}

var civFilters = []civFilter{
	{name: "FIL1", code: 0x01},
	{name: "FIL2", code: 0x02},
	{name: "FIL3", code: 0x03},
}

type civBand struct {
	freqFrom uint
	freqTo   uint
	freq     uint
}

var civBands = []civBand{
	{freqFrom: 1800000, freqTo: 1999999},     // 1.9
	{freqFrom: 3400000, freqTo: 4099999},     // 3.5
	{freqFrom: 6900000, freqTo: 7499999},     // 7
	{freqFrom: 9900000, freqTo: 10499999},    // 10
	{freqFrom: 13900000, freqTo: 14499999},   // 14
	{freqFrom: 17900000, freqTo: 18499999},   // 18
	{freqFrom: 20900000, freqTo: 21499999},   // 21
	{freqFrom: 24400000, freqTo: 25099999},   // 24
	{freqFrom: 28000000, freqTo: 29999999},   // 28
	{freqFrom: 50000000, freqTo: 54000000},   // 50
	{freqFrom: 74800000, freqTo: 107999999},  // WFM
	{freqFrom: 108000000, freqTo: 136999999}, // AIR
	{freqFrom: 144000000, freqTo: 148000000}, // 144
	{freqFrom: 420000000, freqTo: 450000000}, // 430
	{freqFrom: 0, freqTo: 0},                 // GENE
}

type civControlStruct struct {
	st              *serialStream
	deinitNeeded    chan bool
	deinitFinished  chan bool
	resetSReadTimer chan bool

	state struct {
		getSSent   bool
		getOVFSent bool
		getSWRSent bool

		freq             uint
		ptt              bool
		tune             bool
		pwrPercent       int
		rfGainPercent    int
		sqlPercent       int
		nrPercent        int
		nrEnabled        bool
		operatingModeIdx int
		filterIdx        int
		dataMode         bool
		bandIdx          int
		bandChanging     bool
		preamp           int
		tsValue          byte
		ts               uint
	}
}

var civControl *civControlStruct

// Returns false if the message should not be forwarded to the serial port TCP server or the virtual serial port.
func (s *civControlStruct) decode(d []byte) bool {
	if len(d) < 6 || d[0] != 0xfe || d[1] != 0xfe || d[len(d)-1] != 0xfd {
		return true
	}

	payload := d[5 : len(d)-1]

	switch d[4] {
	case 0x00:
		s.decodeFreq(payload)
	case 0x01:
		s.decodeMode(payload)
	case 0x03:
		s.decodeFreq(payload)
	case 0x04:
		s.decodeMode(payload)
	case 0x10:
		s.decodeTS(payload)
	case 0x1a:
		return s.decodeDataModeAndOVF(payload)
	case 0x14:
		s.decodePowerRFGainSQLNR(payload)
	case 0x1c:
		s.decodeTransmitStatus(payload)
	case 0x15:
		return s.decodeVdSWRS(payload)
	case 0x16:
		s.decodePreampAndNR(payload)
	}
	return true
}

func (s *civControlStruct) decodeFreq(d []byte) {
	var f uint
	var pos int
	for _, v := range d {
		s1 := v & 0x0f
		s2 := v >> 4
		f += uint(s1) * uint(math.Pow(10, float64(pos)))
		pos++
		f += uint(s2) * uint(math.Pow(10, float64(pos)))
		pos++
	}
	if f == 0 {
		return
	}
	s.state.freq = f
	statusLog.reportFrequency(s.state.freq)

	s.state.bandIdx = len(civBands) - 1 // Set the band idx to GENE by default.
	for i := range civBands {
		if s.state.freq >= civBands[i].freqFrom && s.state.freq <= civBands[i].freqTo {
			s.state.bandIdx = i
			civBands[s.state.bandIdx].freq = s.state.freq
			break
		}
	}
}

func (s *civControlStruct) decodeFilterValueToFilterIdx(v byte) int {
	for i := range civFilters {
		if civFilters[i].code == v {
			return i
		}
	}
	return -1
}

func (s *civControlStruct) decodeMode(d []byte) {
	if len(d) < 1 {
		return
	}

	var mode string
	for i := range civOperatingModes {
		if civOperatingModes[i].code == d[0] {
			s.state.operatingModeIdx = i
			mode = civOperatingModes[i].name
			break
		}
	}

	var filter string
	if len(d) > 1 {
		s.state.filterIdx = s.decodeFilterValueToFilterIdx(d[1])
		filter = civFilters[s.state.filterIdx].name
	}
	statusLog.reportMode(mode, filter)

	// The transceiver does not send the data mode setting automatically.
	_ = s.getDataMode()
}

func (s *civControlStruct) decodeTS(d []byte) {
	if len(d) < 1 {
		return
	}

	s.state.tsValue = d[0]

	switch s.state.tsValue {
	default:
		s.state.ts = 1
	case 1:
		s.state.ts = 100
	case 2:
		s.state.ts = 500
	case 3:
		s.state.ts = 1000
	case 4:
		s.state.ts = 5000
	case 5:
		s.state.ts = 6250
	case 6:
		s.state.ts = 8330
	case 7:
		s.state.ts = 9000
	case 8:
		s.state.ts = 10000
	case 9:
		s.state.ts = 12500
	case 10:
		s.state.ts = 20000
	case 11:
		s.state.ts = 25000
	case 12:
		s.state.ts = 50000
	case 13:
		s.state.ts = 100000
	}
	statusLog.reportTS(s.state.ts)
}

func (s *civControlStruct) decodeDataModeAndOVF(d []byte) bool {
	if len(d) < 1 {
		return true
	}

	switch d[0] {
	case 0x06:
		if len(d) < 3 {
			return true
		}
		var dataMode string
		var filter string
		if d[1] == 1 {
			dataMode = "-D"
			s.state.dataMode = true
			s.state.filterIdx = s.decodeFilterValueToFilterIdx(d[2])
			filter = civFilters[s.state.filterIdx].name
		} else {
			s.state.dataMode = false
		}

		statusLog.reportDataMode(dataMode, filter)
	case 0x09:
		if len(d) < 2 {
			return !s.state.getOVFSent
		}
		if d[1] != 0 {
			statusLog.reportOVF(true)
		} else {
			statusLog.reportOVF(false)
		}
		if s.state.getOVFSent {
			s.state.getOVFSent = false
			return false
		}
	}
	return true
}

func (s *civControlStruct) decodePowerRFGainSQLNR(d []byte) {
	if len(d) < 3 {
		return
	}

	switch d[0] {
	case 0x02:
		hex := uint16(d[1])<<8 | uint16(d[2])
		s.state.rfGainPercent = int(math.Round((float64(hex) / 0x0255) * 100))
		statusLog.reportRFGain(s.state.rfGainPercent)
	case 0x03:
		hex := uint16(d[1])<<8 | uint16(d[2])
		s.state.sqlPercent = int(math.Round((float64(hex) / 0x0255) * 100))
		statusLog.reportSQL(s.state.sqlPercent)
	case 0x06:
		hex := uint16(d[1])<<8 | uint16(d[2])
		s.state.nrPercent = int(math.Round((float64(hex) / 0x0255) * 100))
		statusLog.reportNR(s.state.nrPercent)
	case 0x0a:
		hex := uint16(d[1])<<8 | uint16(d[2])
		s.state.pwrPercent = int(math.Round((float64(hex) / 0x0255) * 100))
		statusLog.reportTxPower(s.state.pwrPercent)
	}
}

func (s *civControlStruct) decodeTransmitStatus(d []byte) {
	if len(d) < 2 {
		return
	}

	switch d[0] {
	case 0:
		if d[1] == 1 {
			s.state.ptt = true
		} else {
			if s.state.ptt { // PTT released?
				s.state.ptt = false
				_ = s.getVd()
			}
		}
	case 1:
		if d[1] == 2 {
			s.state.tune = true

			// The transceiver does not send the tune state after it's finished.
			time.AfterFunc(time.Second, func() {
				_ = s.getTransmitStatus()
			})
		} else {
			if s.state.tune { // Tune finished?
				s.state.tune = false
				_ = s.getVd()
			}
		}
	}
	statusLog.reportPTT(s.state.ptt, s.state.tune)
}

func (s *civControlStruct) decodeVdSWRS(d []byte) bool {
	if len(d) < 1 {
		return true
	}

	switch d[0] {
	case 0x02:
		if len(d) < 3 {
			return !s.state.getSSent
		}
		sValue := (int(math.Round(((float64(int(d[1])<<8) + float64(d[2])) / 0x0241) * 18)))
		sStr := "S"
		if sValue <= 9 {
			sStr += fmt.Sprint(sValue)
		} else {
			sStr += "9+"

			switch sValue {
			case 10:
				sStr += "10"
			case 11:
				sStr += "20"
			case 12:
				sStr += "30"
			case 13:
				sStr += "40"
			case 14:
				sStr += "40"
			case 15:
				sStr += "40"
			case 16:
				sStr += "40"
			case 17:
				sStr += "50"
			case 18:
				sStr += "50"
			default:
				sStr += "60"
			}
		}
		statusLog.reportS(sStr)
		if s.state.getSSent {
			s.state.getSSent = false
			return false
		}
	case 0x12:
		if len(d) < 3 {
			return !s.state.getSWRSent
		}
		statusLog.reportSWR(((float64(int(d[1])<<8) + float64(d[2])) / 0x0241) * 16)
		if s.state.getSWRSent {
			s.state.getSWRSent = false
			return false
		}
	case 0x15:
		if len(d) < 3 {
			return true
		}
		statusLog.reportVd(((float64(int(d[1])<<8) + float64(d[2])) / 0x0241) * 16)
	}
	return true
}

func (s *civControlStruct) decodePreampAndNR(d []byte) {
	if len(d) < 2 {
		return
	}

	switch d[0] {
	case 0x02:
		s.state.preamp = int(d[1])
		statusLog.reportPreamp(s.state.preamp)
	case 0x40:
		if d[1] == 1 {
			s.state.nrEnabled = true
		} else {
			s.state.nrEnabled = false
		}
		statusLog.reportNREnabled(s.state.nrEnabled)
	}
}

func (s *civControlStruct) setPwr(percent int) error {
	v := uint16(0x0255 * (float64(percent) / 100))
	return s.st.send([]byte{254, 254, civAddress, 224, 0x14, 0x0a, byte(v >> 8), byte(v & 0xff), 253})
}

func (s *civControlStruct) incPwr() error {
	if s.state.pwrPercent < 100 {
		return s.setPwr(s.state.pwrPercent + 1)
	}
	return nil
}

func (s *civControlStruct) decPwr() error {
	if s.state.pwrPercent > 0 {
		return s.setPwr(s.state.pwrPercent - 1)
	}
	return nil
}

func (s *civControlStruct) setRFGain(percent int) error {
	v := uint16(0x0255 * (float64(percent) / 100))
	return s.st.send([]byte{254, 254, civAddress, 224, 0x14, 0x02, byte(v >> 8), byte(v & 0xff), 253})
}

func (s *civControlStruct) incRFGain() error {
	if s.state.rfGainPercent < 100 {
		return s.setRFGain(s.state.rfGainPercent + 1)
	}
	return nil
}

func (s *civControlStruct) decRFGain() error {
	if s.state.rfGainPercent > 0 {
		return s.setRFGain(s.state.rfGainPercent - 1)
	}
	return nil
}

func (s *civControlStruct) setSQL(percent int) error {
	v := uint16(0x0255 * (float64(percent) / 100))
	return s.st.send([]byte{254, 254, civAddress, 224, 0x14, 0x03, byte(v >> 8), byte(v & 0xff), 253})
}

func (s *civControlStruct) incSQL() error {
	if s.state.sqlPercent < 100 {
		return s.setSQL(s.state.sqlPercent + 1)
	}
	return nil
}

func (s *civControlStruct) decSQL() error {
	if s.state.sqlPercent > 0 {
		return s.setSQL(s.state.sqlPercent - 1)
	}
	return nil
}

func (s *civControlStruct) setNR(percent int) error {
	v := uint16(0x0255 * (float64(percent) / 100))
	return s.st.send([]byte{254, 254, civAddress, 224, 0x14, 0x06, byte(v >> 8), byte(v & 0xff), 253})
}

func (s *civControlStruct) incNR() error {
	if s.state.nrPercent < 100 {
		return s.setNR(s.state.nrPercent + 1)
	}
	return nil
}

func (s *civControlStruct) decNR() error {
	if s.state.nrPercent > 0 {
		return s.setNR(s.state.nrPercent - 1)
	}
	return nil
}

func (s *civControlStruct) getDigit(v uint, n int) byte {
	f := float64(v)
	for n > 0 {
		f /= 10
		n--
	}
	return byte(uint(f) % 10)
}

func (s *civControlStruct) incFreq() error {
	return s.setFreq(s.state.freq + s.state.ts)
}

func (s *civControlStruct) decFreq() error {
	return s.setFreq(s.state.freq - s.state.ts)
}

func (s *civControlStruct) setFreq(f uint) error {
	var b [5]byte
	v0 := s.getDigit(f, 9)
	v1 := s.getDigit(f, 8)
	b[4] = v0<<4 | v1
	v0 = s.getDigit(f, 7)
	v1 = s.getDigit(f, 6)
	b[3] = v0<<4 | v1
	v0 = s.getDigit(f, 5)
	v1 = s.getDigit(f, 4)
	b[2] = v0<<4 | v1
	v0 = s.getDigit(f, 3)
	v1 = s.getDigit(f, 2)
	b[1] = v0<<4 | v1
	v0 = s.getDigit(f, 1)
	v1 = s.getDigit(f, 0)
	b[0] = v0<<4 | v1
	if err := s.st.send([]byte{254, 254, civAddress, 224, 5, b[0], b[1], b[2], b[3], b[4], 253}); err != nil {
		return err
	}
	// The transceiver does not send the new freq automatically.
	return s.getFreq()
}

func (s *civControlStruct) incOperatingMode() error {
	s.state.operatingModeIdx++
	if s.state.operatingModeIdx >= len(civOperatingModes) {
		s.state.operatingModeIdx = 0
	}
	return civControl.setOperatingModeAndFilter(civOperatingModes[s.state.operatingModeIdx].code,
		civFilters[s.state.filterIdx].code)
}

func (s *civControlStruct) decOperatingMode() error {
	s.state.operatingModeIdx--
	if s.state.operatingModeIdx < 0 {
		s.state.operatingModeIdx = len(civOperatingModes) - 1
	}
	return civControl.setOperatingModeAndFilter(civOperatingModes[s.state.operatingModeIdx].code,
		civFilters[s.state.filterIdx].code)
}

func (s *civControlStruct) incFilter() error {
	s.state.filterIdx++
	if s.state.filterIdx >= len(civFilters) {
		s.state.filterIdx = 0
	}
	return civControl.setOperatingModeAndFilter(civOperatingModes[s.state.operatingModeIdx].code,
		civFilters[s.state.filterIdx].code)
}

func (s *civControlStruct) decFilter() error {
	s.state.filterIdx--
	if s.state.filterIdx < 0 {
		s.state.filterIdx = len(civFilters) - 1
	}
	return civControl.setOperatingModeAndFilter(civOperatingModes[s.state.operatingModeIdx].code,
		civFilters[s.state.filterIdx].code)
}

func (s *civControlStruct) setOperatingModeAndFilter(modeCode, filterCode byte) error {
	if err := s.st.send([]byte{254, 254, civAddress, 224, 0x06, modeCode, filterCode, 253}); err != nil {
		return err
	}
	return s.getMode()
}

func (s *civControlStruct) setPTT(enable bool) error {
	var b byte
	if enable {
		b = 1
	}
	return s.st.send([]byte{254, 254, civAddress, 224, 0x1c, 0, b, 253})
}

func (s *civControlStruct) toggleTune() error {
	if s.state.ptt {
		return nil
	}

	var b byte
	if !s.state.tune {
		b = 2
	} else {
		b = 1
	}
	return s.st.send([]byte{254, 254, civAddress, 224, 0x1c, 1, b, 253})
}

func (s *civControlStruct) toggleDataMode() error {
	var b byte
	var f byte
	if !s.state.dataMode {
		b = 1
		f = 1
	} else {
		b = 0
		f = 0
	}
	return s.st.send([]byte{254, 254, civAddress, 224, 0x1a, 0x06, b, f, 253})
}

func (s *civControlStruct) incBand() error {
	s.state.bandChanging = true
	i := s.state.bandIdx + 1
	if i >= len(civBands) {
		i = 0
	}
	f := civBands[i].freq
	if f == 0 {
		f = (civBands[i].freqFrom + civBands[i].freqTo) / 2
	}
	return s.setFreq(f)
}

func (s *civControlStruct) decBand() error {
	s.state.bandChanging = true
	i := s.state.bandIdx - 1
	if i < 0 {
		i = len(civBands) - 1
	}
	f := civBands[i].freq
	if f == 0 {
		f = civBands[i].freqFrom
	}
	return s.setFreq(f)
}

func (s *civControlStruct) togglePreamp() error {
	b := byte(s.state.preamp + 1)
	if b > 2 {
		b = 0
	}
	return s.st.send([]byte{254, 254, civAddress, 224, 0x16, 0x02, b, 253})
}

func (s *civControlStruct) toggleNR() error {
	var b byte
	if !s.state.nrEnabled {
		b = 1
	}
	return s.st.send([]byte{254, 254, civAddress, 224, 0x16, 0x40, b, 253})
}

func (s *civControlStruct) incTS() error {
	var b byte
	if s.state.tsValue == 13 {
		b = 0
	} else {
		b = s.state.tsValue + 1
	}
	return s.st.send([]byte{254, 254, civAddress, 224, 0x10, b, 253})
}

func (s *civControlStruct) decTS() error {
	var b byte
	if s.state.tsValue == 0 {
		b = 13
	} else {
		b = s.state.tsValue - 1
	}
	return s.st.send([]byte{254, 254, civAddress, 224, 0x10, b, 253})
}

func (s *civControlStruct) getFreq() error {
	return s.st.send([]byte{254, 254, civAddress, 224, 3, 253})
}

func (s *civControlStruct) getMode() error {
	return s.st.send([]byte{254, 254, civAddress, 224, 4, 253})
}

func (s *civControlStruct) getDataMode() error {
	return s.st.send([]byte{254, 254, civAddress, 224, 0x1a, 0x06, 253})
}

func (s *civControlStruct) getTransmitStatus() error {
	if err := s.st.send([]byte{254, 254, civAddress, 224, 0x1c, 0, 253}); err != nil {
		return err
	}
	return s.st.send([]byte{254, 254, civAddress, 224, 0x1c, 1, 253})
}

func (s *civControlStruct) getVd() error {
	return s.st.send([]byte{254, 254, civAddress, 224, 0x15, 0x15, 253})
}

func (s *civControlStruct) getS() error {
	s.state.getSSent = true
	return s.st.send([]byte{254, 254, civAddress, 224, 0x15, 0x02, 253})
}

func (s *civControlStruct) getOVF() error {
	s.state.getOVFSent = true
	return s.st.send([]byte{254, 254, civAddress, 224, 0x1a, 0x09, 253})
}

func (s *civControlStruct) getSWR() error {
	s.state.getSWRSent = true
	return s.st.send([]byte{254, 254, civAddress, 224, 0x15, 0x12, 253})
}

func (s *civControlStruct) getTS() error {
	return s.st.send([]byte{254, 254, civAddress, 224, 0x10, 253})
}

func (s *civControlStruct) getRFGain() error {
	return s.st.send([]byte{254, 254, civAddress, 224, 0x14, 0x02, 253})
}

func (s *civControlStruct) getSQL() error {
	return s.st.send([]byte{254, 254, civAddress, 224, 0x14, 0x03, 253})
}

func (s *civControlStruct) getNR() error {
	return s.st.send([]byte{254, 254, civAddress, 224, 0x14, 0x06, 253})
}

func (s *civControlStruct) getNREnabled() error {
	return s.st.send([]byte{254, 254, civAddress, 224, 0x16, 0x40, 253})
}

func (s *civControlStruct) loop() {
	for {
		select {
		case <-s.deinitNeeded:
			s.deinitFinished <- true
			return
		case <-time.After(sReadInterval):
			_ = s.getS()
			_ = s.getOVF()
			_ = s.getSWR()
		case <-s.resetSReadTimer:
		}
	}
}

func (s *civControlStruct) init(st *serialStream) error {
	s.st = st

	if err := s.getFreq(); err != nil {
		return err
	}
	if err := s.getMode(); err != nil {
		return err
	}
	if err := s.getDataMode(); err != nil {
		return err
	}
	// Querying power.
	if err := s.st.send([]byte{254, 254, civAddress, 224, 0x14, 0x0a, 253}); err != nil {
		return err
	}
	if err := s.getTransmitStatus(); err != nil {
		return err
	}
	// Querying preamp.
	if err := s.st.send([]byte{254, 254, civAddress, 224, 0x16, 0x02, 253}); err != nil {
		return err
	}
	if err := s.getVd(); err != nil {
		return err
	}
	if err := s.getS(); err != nil {
		return err
	}
	if err := s.getOVF(); err != nil {
		return err
	}
	if err := s.getSWR(); err != nil {
		return err
	}
	if err := s.getTS(); err != nil {
		return err
	}
	if err := s.getRFGain(); err != nil {
		return err
	}
	if err := s.getSQL(); err != nil {
		return err
	}
	if err := s.getNR(); err != nil {
		return err
	}
	if err := s.getNREnabled(); err != nil {
		return err
	}

	s.deinitNeeded = make(chan bool)
	s.deinitFinished = make(chan bool)
	s.resetSReadTimer = make(chan bool)
	go s.loop()
	return nil
}

func (s *civControlStruct) deinit() {
	if s.deinitNeeded != nil {
		s.deinitNeeded <- true
		<-s.deinitFinished
	}
	s.deinitNeeded = nil
}