package main

import (
	"bytes"
	"crypto/rand"
	"encoding/binary"
	"errors"
	"time"
)

const controlStreamPort = 50001
const serialStreamPort = 50002
const audioStreamPort = 50003

const reauthInterval = time.Minute
const reauthTimeout = 3 * time.Second

type controlStream struct {
	common streamCommon
	serial serialStream
	audio  audioStream

	deinitNeededChan   chan bool
	deinitFinishedChan chan bool

	authInnerSendSeq uint16
	authID           [6]byte
	gotAuthID        bool
	authOk           bool

	a8replyID    [16]byte
	gotA8ReplyID bool

	serialAndAudioStreamOpened bool
	deinitializing             bool

	requestSerialAndAudioTimeout *time.Timer
	reauthTimeoutTimer           *time.Timer
}

func (s *controlStream) sendPktLogin() error {
	// The reply to the auth packet will contain a 6 bytes long auth ID with the first 2 bytes set to our ID.
	var authStartID [2]byte
	if _, err := rand.Read(authStartID[:]); err != nil {
		return err
	}
	usernameEncoded := passcode(username)
	passwordEncoded := passcode(password)
	p := []byte{0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		byte(s.common.localSID >> 24), byte(s.common.localSID >> 16), byte(s.common.localSID >> 8), byte(s.common.localSID),
		byte(s.common.remoteSID >> 24), byte(s.common.remoteSID >> 16), byte(s.common.remoteSID >> 8), byte(s.common.remoteSID),
		0x00, 0x00, 0x00, 0x70, 0x01, 0x00, 0x00, byte(s.authInnerSendSeq),
		byte(s.authInnerSendSeq >> 8), 0x00, authStartID[0], authStartID[1], 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		usernameEncoded[0], usernameEncoded[1], usernameEncoded[2], usernameEncoded[3],
		usernameEncoded[4], usernameEncoded[5], usernameEncoded[6], usernameEncoded[7],
		usernameEncoded[8], usernameEncoded[9], usernameEncoded[10], usernameEncoded[11],
		usernameEncoded[12], usernameEncoded[13], usernameEncoded[14], usernameEncoded[15],
		passwordEncoded[0], passwordEncoded[1], passwordEncoded[2], passwordEncoded[3],
		passwordEncoded[4], passwordEncoded[5], passwordEncoded[6], passwordEncoded[7],
		passwordEncoded[8], passwordEncoded[9], passwordEncoded[10], passwordEncoded[11],
		passwordEncoded[12], passwordEncoded[13], passwordEncoded[14], passwordEncoded[15],
		0x69, 0x63, 0x6f, 0x6d, 0x2d, 0x70, 0x63, 0x00, // icom-pc in plain text
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
	if err := s.common.pkt0.sendTrackedPacket(&s.common, p); err != nil {
		return err
	}

	s.authInnerSendSeq++
	return nil
}

func (s *controlStream) sendPktAuth(magic byte) error {
	// Example request from PC:  0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0d, 0x00,
	//                           0xbb, 0x41, 0x3f, 0x2b, 0xe6, 0xb2, 0x7b, 0x7b,
	//                           0x00, 0x00, 0x00, 0x30, 0x01, 0x05, 0x00, 0x02,
	//                           0x00, 0x00, 0x5d, 0x37, 0x12, 0x82, 0x3b, 0xde,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
	// Example reply from radio: 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0e, 0x00,
	//                           0xe6, 0xb2, 0x7b, 0x7b, 0xbb, 0x41, 0x3f, 0x2b,
	//                           0x00, 0x00, 0x00, 0x30, 0x02, 0x05, 0x00, 0x02,
	//                           0x00, 0x00, 0x5d, 0x37, 0x12, 0x82, 0x3b, 0xde,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00

	p := []byte{0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		byte(s.common.localSID >> 24), byte(s.common.localSID >> 16), byte(s.common.localSID >> 8), byte(s.common.localSID),
		byte(s.common.remoteSID >> 24), byte(s.common.remoteSID >> 16), byte(s.common.remoteSID >> 8), byte(s.common.remoteSID),
		0x00, 0x00, 0x00, 0x30, 0x01, magic, 0x00, byte(s.authInnerSendSeq),
		byte(s.authInnerSendSeq >> 8), 0x00, s.authID[0], s.authID[1], s.authID[2], s.authID[3], s.authID[4], s.authID[5],
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
	if err := s.common.pkt0.sendTrackedPacket(&s.common, p); err != nil {
		return err
	}
	s.authInnerSendSeq++
	return nil
}

func (s *controlStream) sendRequestSerialAndAudio() error {
	log.Debug("requesting serial and audio stream")

	txSeqBufLengthMs := uint16(txSeqBufLength.Milliseconds())

	usernameEncoded := passcode(username)
	p := []byte{0x90, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		byte(s.common.localSID >> 24), byte(s.common.localSID >> 16), byte(s.common.localSID >> 8), byte(s.common.localSID),
		byte(s.common.remoteSID >> 24), byte(s.common.remoteSID >> 16), byte(s.common.remoteSID >> 8), byte(s.common.remoteSID),
		0x00, 0x00, 0x00, 0x80, 0x01, 0x03, 0x00, byte(s.authInnerSendSeq),
		byte(s.authInnerSendSeq >> 8), 0x00, s.authID[0], s.authID[1], s.authID[2], s.authID[3], s.authID[4], s.authID[5],
		s.a8replyID[0], s.a8replyID[1], s.a8replyID[2], s.a8replyID[3], s.a8replyID[4], s.a8replyID[5], s.a8replyID[6], s.a8replyID[7],
		s.a8replyID[8], s.a8replyID[9], s.a8replyID[10], s.a8replyID[11], s.a8replyID[12], s.a8replyID[13], s.a8replyID[14], s.a8replyID[15],
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x49, 0x43, 0x2d, 0x37, 0x30, 0x35, 0x00, 0x00, // IC-705 in plain text
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		usernameEncoded[0], usernameEncoded[1], usernameEncoded[2], usernameEncoded[3],
		usernameEncoded[4], usernameEncoded[5], usernameEncoded[6], usernameEncoded[7],
		usernameEncoded[8], usernameEncoded[9], usernameEncoded[10], usernameEncoded[11],
		usernameEncoded[12], usernameEncoded[13], usernameEncoded[14], usernameEncoded[15],
		0x01, 0x01, 0x04, 0x04, 0x00, 0x00, byte(audioSampleRate >> 8), byte(audioSampleRate & 0xff),
		0x00, 0x00, byte(audioSampleRate >> 8), byte(audioSampleRate & 0xff),
		0x00, 0x00, byte(serialStreamPort >> 8), byte(serialStreamPort & 0xff),
		0x00, 0x00, byte(audioStreamPort >> 8), byte(audioStreamPort & 0xff), 0x00, 0x00,
		byte(txSeqBufLengthMs >> 8), byte(txSeqBufLengthMs & 0xff), 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
	if err := s.common.pkt0.sendTrackedPacket(&s.common, p); err != nil {
		return err
	}

	s.authInnerSendSeq++

	return nil
}

func (s *controlStream) sendRequestSerialAndAudioIfPossible() {
	if !s.serialAndAudioStreamOpened && s.authOk && s.gotA8ReplyID {
		if err := s.sendRequestSerialAndAudio(); err != nil {
			reportError(err)
		}
	}
}

func (s *controlStream) handleRead(r []byte) error {
	switch len(r) {
	case 168:
		if bytes.Equal(r[:6], []byte{0xa8, 0x00, 0x00, 0x00, 0x00, 0x00}) {
			// Example answer from radio:
			// 0xa8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00,
			// 0x01, 0x13, 0x11, 0x18, 0x38, 0xff, 0x55, 0x7d,
			// 0x00, 0x00, 0x00, 0x98, 0x02, 0x02, 0x00, 0x07,
			// 0x00, 0x00, 0x7f, 0x91, 0x00, 0x00, 0x4f, 0x0d,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x01, 0x93, 0x8a, 0x01, 0x24, 0x17, 0x64,
			// 0xbc, 0x4b, 0xa3, 0xa0, 0x13, 0x58, 0x41, 0x04,
			// 0x58, 0x2d, 0x49, 0x43, 0x2d, 0x37, 0x30, 0x35,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x49, 0x43, 0x4f, 0x4d, 0x5f, 0x56,
			// 0x41, 0x55, 0x44, 0x49, 0x4f, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x3f, 0x3f, 0xa4, 0x01, 0xff, 0x01,
			// 0xff, 0x01, 0x01, 0x01, 0x00, 0x00, 0x4b, 0x00,
			// 0x01, 0x50, 0x00, 0xb8, 0x0b, 0x00, 0x00, 0x00
			copy(s.a8replyID[:], r[66:82])
			s.gotA8ReplyID = true
		}
	case 64:
		if bytes.Equal(r[:6], []byte{0x40, 0x00, 0x00, 0x00, 0x00, 0x00}) {
			// Example answer from radio:   0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00,
			// 0x33, 0x60, 0xd4, 0xe5, 0xf4, 0x67, 0x86, 0xe1,
			// 0x00, 0x00, 0x00, 0x30, 0x02, 0x05, 0x00, 0x02,
			// 0x00, 0x00, 0x35, 0x34, 0x76, 0x11, 0xb9, 0xd0,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00

			s.reauthTimeoutTimer.Stop()

			log.Debug("auth ok")

			if r[21] == 0x05 { // Answer for our second auth?
				s.authOk = true
				s.sendRequestSerialAndAudioIfPossible()
			}
		}
	case 80:
		if bytes.Equal(r[:6], []byte{0x50, 0x00, 0x00, 0x00, 0x00, 0x00}) {
			// Example answer from radio: 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00,
			//							  0x86, 0x1f, 0x2f, 0xcc, 0x03, 0x03, 0x89, 0x29,
			//							  0x00, 0x00, 0x00, 0x40, 0x02, 0x03, 0x00, 0x52,
			//							  0x00, 0x00, 0xf8, 0xad, 0x06, 0x8d, 0xda, 0x7b,
			//							  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10,
			//							  0x80, 0x00, 0x00, 0x90, 0xc7, 0x0e, 0x86, 0x01,
			//							  0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
			//							  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			//							  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			//							  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00

			if bytes.Equal(r[48:51], []byte{0xff, 0xff, 0xff}) {
				if !s.serialAndAudioStreamOpened {
					return errors.New("auth failed, try rebooting the radio")
				}
				return errors.New("auth failed")
			}
			if bytes.Equal(r[48:51], []byte{0x00, 0x00, 0x00}) && r[64] == 0x01 {
				return errors.New("got radio disconnected")
			}
		}
	case 144:
		if !s.serialAndAudioStreamOpened && bytes.Equal(r[:6], []byte{0x90, 0x00, 0x00, 0x00, 0x00, 0x00}) && r[96] == 1 {
			// Example answer:
			// 0x90, 0x00, 0x00, 0x00, 0x00, 0x00, 0x19, 0x00,
			// 0xc6, 0x5f, 0x6f, 0x0c, 0x5f, 0x8b, 0x1e, 0x89,
			// 0x00, 0x00, 0x00, 0x80, 0x03, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x31, 0x30, 0x31, 0x47, 0x39, 0x07,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10,
			// 0x80, 0x00, 0x00, 0x90, 0xc7, 0x0e, 0x86, 0x01,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x49, 0x43, 0x2d, 0x37, 0x30, 0x35, 0x00, 0x00, // IC-705 in plain text
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x01, 0x00, 0x00, 0x00, 0x69, 0x63, 0x6f, 0x6d,
			// 0x2d, 0x70, 0x63, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0xc0, 0xa8, 0x03, 0x03,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00

			s.requestSerialAndAudioTimeout.Stop()

			devName := parseNullTerminatedString(r[64:])
			log.Print("got serial and audio request success, device name: ", devName)

			// Stuff can change in the meantime because of a previous login...
			s.common.remoteSID = binary.BigEndian.Uint32(r[8:12])
			s.common.localSID = binary.BigEndian.Uint32(r[12:16])
			copy(s.authID[:], r[26:32])
			s.gotAuthID = true

			if err := s.serial.init(devName); err != nil {
				return errors.New("serial/" + err.Error())
			}

			if err := s.audio.init(devName); err != nil {
				return errors.New("audio/" + err.Error())
			}

			s.serialAndAudioStreamOpened = true
			statusLog.startPeriodicPrint()

			runCmdRunner.startIfNeeded(runCmd)
			if enableSerialDevice {
				serialCmdRunner.startIfNeeded(runCmdOnSerialPortCreated)
			}
			if err := rigctld.initIfNeeded(); err != nil {
				return err
			}
		}
	}
	return nil
}

func (s *controlStream) loop() {
	netstat.reset()

	s.reauthTimeoutTimer = time.NewTimer(0)
	<-s.reauthTimeoutTimer.C

	reauthTicker := time.NewTicker(reauthInterval)

	for {
		select {
		case r := <-s.common.readChan:
			if !s.deinitializing {
				if err := s.handleRead(r); err != nil {
					reportError(err)
				}
			}
		case <-reauthTicker.C:
			log.Debug("sending auth")
			s.reauthTimeoutTimer.Reset(reauthTimeout)
			if err := s.sendPktAuth(0x05); err != nil {
				reportError(err)
			}
		case <-s.reauthTimeoutTimer.C:
			log.Error("auth timeout, audio/serial stream may stop")
		case <-s.deinitNeededChan:
			s.deinitFinishedChan <- true
			return
		}
	}
}

func (s *controlStream) init() error {
	log.Debug("init")

	if err := s.common.init("control", controlStreamPort); err != nil {
		return err
	}

	if err := s.common.start(); err != nil {
		return err
	}

	s.common.pkt0.init(&s.common)
	if err := s.sendPktLogin(); err != nil {
		return err
	}

	log.Debug("expecting login answer")
	// Example success auth packet: 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00,
	//                              0xe6, 0xb2, 0x7b, 0x7b, 0xbb, 0x41, 0x3f, 0x2b,
	//                              0x00, 0x00, 0x00, 0x50, 0x02, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x5d, 0x37, 0x12, 0x82, 0x3b, 0xde,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x46, 0x54, 0x54, 0x48, 0x00, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
	r, err := s.common.expect(96, []byte{0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00})
	if err != nil {
		return err
	}
	if bytes.Equal(r[48:52], []byte{0xff, 0xff, 0xff, 0xfe}) {
		return errors.New("invalid username/password")
	}

	s.common.pkt7.startPeriodicSend(&s.common, 2, false)

	copy(s.authID[:], r[26:32])
	s.gotAuthID = true
	if err := s.sendPktAuth(0x02); err != nil {
		return err
	}
	log.Debug("login ok, first auth sent...")

	s.common.pkt0.startPeriodicSend(&s.common)

	if err := s.sendPktAuth(0x05); err != nil {
		return err
	}
	log.Debug("second auth sent...")

	s.requestSerialAndAudioTimeout = time.AfterFunc(5*time.Second, func() {
		reportError(errors.New("login/serial/audio request timeout"))
	})

	s.deinitNeededChan = make(chan bool)
	s.deinitFinishedChan = make(chan bool)
	go s.loop()
	return nil
}

func (s *controlStream) deinit() {
	s.deinitializing = true
	s.serialAndAudioStreamOpened = false
	statusLog.stopPeriodicPrint()

	if s.deinitNeededChan != nil {
		s.deinitNeededChan <- true
		<-s.deinitFinishedChan
	}
	if s.requestSerialAndAudioTimeout != nil {
		s.requestSerialAndAudioTimeout.Stop()
		s.requestSerialAndAudioTimeout = nil
	}

	if s.gotAuthID && s.common.gotRemoteSID && s.common.conn != nil {
		log.Debug("sending deauth")
		_ = s.sendPktAuth(0x01)
		// Waiting a little bit to make sure the radio can send retransmit requests.
		time.Sleep(500 * time.Millisecond)
	}

	s.common.deinit()
	s.serial.deinit()
	s.audio.deinit()
}