package main

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

	"github.com/nonoo/kappanhang/log"
)

type controlStream struct {
	common streamCommon
	serial serialStream
	audio  audioStream

	deinitNeededChan   chan bool
	deinitFinishedChan chan bool

	authSendSeq      uint16
	authInnerSendSeq uint16
	authID           [6]byte

	serialAndAudioStreamOpened bool

	requestSerialAndAudioTimeout *time.Timer
}

func (s *controlStream) sendPktAuth() error {
	// The reply to the auth packet will contain a 6 bytes long auth ID with the first 2 bytes set to our randID.
	var randID [2]byte
	if _, err := rand.Read(randID[:]); err != nil {
		return err
	}
	p := []byte{0x80, 0x00, 0x00, 0x00, 0x00, 0x00, byte(s.authSendSeq), byte(s.authSendSeq >> 8),
		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, randID[0], randID[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,
		0x2b, 0x3f, 0x55, 0x5c, 0x00, 0x00, 0x00, 0x00, // username: beer
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x2b, 0x3f, 0x55, 0x5c, 0x3f, 0x25, 0x77, 0x58, // pass: beerbeer
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		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.send(p); err != nil {
		return err
	}
	if err := s.common.send(p); err != nil {
		return err
	}

	s.authSendSeq++
	s.authInnerSendSeq++
	return nil
}

func (s *controlStream) sendPktReauth(firstReauthSend bool) error {
	var magic byte

	if firstReauthSend {
		magic = 0x02
	} else {
		magic = 0x05
	}

	// 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, byte(s.authSendSeq), byte(s.authSendSeq >> 8),
		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.send(p); err != nil {
		return err
	}
	if err := s.common.send(p); err != nil {
		return err
	}
	s.authSendSeq++
	s.authInnerSendSeq++
	return nil
}

// func (s *controlStream) sendDisconnect() { TODO
// 	if s.common.conn == nil {
// 		return
// 	}
// s.common.send([]byte{0x40, 0x00, 0x00, 0x00, 0x00, 0x00, byte(s.authSendSeq), byte(s.authSendSeq >> 8),
// 	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, 0x01, 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})
// 	s.common.sendDisconnect()
// }

func (s *controlStream) sendPkt0() error {
	p := []byte{0x10, 0x00, 0x00, 0x00, 0x00, 0x00, byte(s.authSendSeq), byte(s.authSendSeq >> 8),
		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)}
	if err := s.common.send(p); err != nil {
		return err
	}
	if err := s.common.send(p); err != nil {
		return err
	}
	s.authSendSeq++
	return nil
}

func (s *controlStream) sendRequestSerialAndAudio() error {
	log.Print("requesting serial and audio stream")
	p := []byte{0x90, 0x00, 0x00, 0x00, 0x00, 0x00, byte(s.authSendSeq), byte(s.authSendSeq >> 8),
		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],
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10,
		0x80, 0x00, 0x00, 0x90, 0xc7, 0x0e, 0x86, 0x01, // The last 5 bytes from this row can be acquired from a reply starting with 0xa8 or 0x90
		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,
		0x2b, 0x3f, 0x55, 0x5c, 0x00, 0x00, 0x00, 0x00, // username: beer
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x01, 0x01, 0x04, 0x04, 0x00, 0x00, 0xbb, 0x80,
		0x00, 0x00, 0xbb, 0x80, 0x00, 0x00, 0xc3, 0x52,
		0x00, 0x00, 0xc3, 0x53, 0x00, 0x00, 0x00, 0xa0,
		0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
	if err := s.common.send(p); err != nil {
		return err
	}
	if err := s.common.send(p); err != nil {
		return err
	}

	s.authSendSeq++
	s.authInnerSendSeq++

	s.requestSerialAndAudioTimeout = time.AfterFunc(3*time.Second, func() {
		reportError(errors.New("serial and audio request timeout"))
	})
	return nil
}

func (s *controlStream) parseNullTerminatedString(d []byte) (res string) {
	nullIndex := strings.Index(string(d), "\x00")
	if nullIndex > 0 {
		res = string(d[:nullIndex])
	}
	return
}

func (s *controlStream) handleRead(r []byte) error {
	switch len(r) {
	case 16:
		if bytes.Equal(r[:6], []byte{0x10, 0x00, 0x00, 0x00, 0x00, 0x00}) {
			// Replying to the radio.
			// Example request from radio: 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x13, 0x00, 0xe4, 0x35, 0xdd, 0x72, 0xbe, 0xd9, 0xf2, 0x63
			// Example answer from PC:     0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x13, 0x00, 0xbe, 0xd9, 0xf2, 0x63, 0xe4, 0x35, 0xdd, 0x72
			gotSeq := binary.LittleEndian.Uint16(r[6:8])
			p := []byte{0x10, 0x00, 0x00, 0x00, 0x00, 0x00, byte(gotSeq), byte(gotSeq >> 8),
				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)}
			if err := s.common.send(p); err != nil {
				return err
			}
			if err := s.common.send(p); err != nil {
				return err
			}
		}
	case 80:
		if bytes.Equal(r[:6], []byte{0x50, 0x00, 0x00, 0x00, 0x00, 0x00}) && bytes.Equal(r[48:51], []byte{0xff, 0xff, 0xff}) {
			// 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

			return errors.New("reauth failed")
		}
	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,
			// 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
			devName := s.parseNullTerminatedString(r[64:])
			log.Print("serial and audio request success, device name: ", devName)
			if s.requestSerialAndAudioTimeout != nil {
				s.requestSerialAndAudioTimeout.Stop()
				s.requestSerialAndAudioTimeout = nil
			}

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

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

			s.serialAndAudioStreamOpened = true
		}
	}
	return nil
}

func (s *controlStream) loop() {
	startTime := time.Now()
	pkt0SendTicker := time.NewTicker(100 * time.Millisecond)
	reauthTicker := time.NewTicker(60 * time.Second)
	statusLogTicker := time.NewTicker(3 * time.Second)

	for {
		select {
		case r := <-s.common.readChan:
			if err := s.handleRead(r); err != nil {
				reportError(err)
			}
		case <-pkt0SendTicker.C:
			if err := s.sendPkt0(); err != nil {
				reportError(err)
			}
		case <-reauthTicker.C:
			if err := s.sendPktReauth(false); err != nil {
				reportError(err)
			}
		case <-statusLogTicker.C:
			if s.serialAndAudioStreamOpened {
				log.Print("running for ", time.Since(startTime), " roundtrip latency ", s.common.pkt7.latency)
			}
		case <-s.deinitNeededChan:
			s.deinitFinishedChan <- true
			return
		}
	}
}

func (s *controlStream) start() error {
	if err := s.common.init("control", 50001); err != nil {
		return err
	}

	if err := s.common.sendPkt3(); err != nil {
		return err
	}
	s.common.pkt7.sendSeq = 1
	if err := s.common.pkt7.send(&s.common); err != nil {
		return err
	}
	if err := s.common.sendPkt3(); err != nil {
		return err
	}
	if err := s.common.waitForPkt4Answer(); err != nil {
		return err
	}
	if err := s.common.sendPkt6(); err != nil {
		return err
	}
	if err := s.common.waitForPkt6Answer(); err != nil {
		return err
	}

	s.authSendSeq = 1
	s.authInnerSendSeq = 1
	if err := s.sendPktAuth(); err != nil {
		return err
	}

	log.Debug("expecting auth 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 user/password")
	}

	copy(s.authID[:], r[26:32])
	log.Print("auth ok, waiting a bit")

	time.AfterFunc(2*time.Second, func() {
		log.Print("sending reauth 1/2...")
		if err := s.sendPktReauth(true); err != nil {
			reportError(err)
		}
		time.AfterFunc(2*time.Second, func() {
			log.Print("sending reauth 2/2...")
			if err := s.sendPktReauth(false); err != nil {
				reportError(err)
			}
			time.AfterFunc(2*time.Second, func() {
				if err := s.sendRequestSerialAndAudio(); err != nil {
					reportError(err)
				}
			})
		})
	})

	s.common.pkt7.startPeriodicSend(&s.common, 5, false)

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

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

	if err := s.serial.init(); err != nil {
		return err
	}
	if err := s.audio.init(); err != nil {
		return err
	}
	return nil
}

func (s *controlStream) deinit() {
	if s.deinitNeededChan != nil {
		s.deinitNeededChan <- true
		<-s.deinitFinishedChan
	}
	if s.requestSerialAndAudioTimeout != nil {
		s.requestSerialAndAudioTimeout.Stop()
		s.requestSerialAndAudioTimeout = nil
	}
	s.audio.deinit()
	s.serial.deinit()
	s.common.deinit()
}