package main

import (
	"bytes"
	"crypto/rand"
	"encoding/binary"
	"os"
	"time"

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

type controlStream struct {
	stream                streamConnection
	authSendSeq           uint16
	authInnerSendSeq      uint16
	authID                [6]byte
	randIDByteForPktSeven [1]byte
	expectedPkt7ReplySeq  uint16
	lastReauthAt          time.Time
}

func (p *controlStream) sendPkt7(replyID []byte, seq uint16) {
	// Example request from PC:  0x15, 0x00, 0x00, 0x00, 0x07, 0x00, 0x09, 0x00, 0xbe, 0xd9, 0xf2, 0x63, 0xe4, 0x35, 0xdd, 0x72, 0x00, 0x78, 0x40, 0xf6, 0x02
	// Example reply from radio: 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x09, 0x00, 0xe4, 0x35, 0xdd, 0x72, 0xbe, 0xd9, 0xf2, 0x63, 0x01, 0x78, 0x40, 0xf6, 0x02
	var replyFlag byte
	if replyID == nil {
		replyID = make([]byte, 4)
		var randID [2]byte
		_, err := rand.Read(randID[:])
		if err != nil {
			log.Fatal(err)
		}
		replyID[0] = randID[0]
		replyID[1] = randID[1]
		replyID[2] = p.randIDByteForPktSeven[0]
		replyID[3] = 0x03
	} else {
		replyFlag = 0x01
	}

	p.expectedPkt7ReplySeq = p.stream.sendSeq

	p.stream.send([]byte{0x15, 0x00, 0x00, 0x00, 0x07, 0x00, byte(seq), byte(seq >> 8),
		byte(p.stream.localSID >> 24), byte(p.stream.localSID >> 16), byte(p.stream.localSID >> 8), byte(p.stream.localSID),
		byte(p.stream.remoteSID >> 24), byte(p.stream.remoteSID >> 16), byte(p.stream.remoteSID >> 8), byte(p.stream.remoteSID),
		replyFlag, replyID[0], replyID[1], replyID[2], replyID[3]})
}

func (p *controlStream) sendPktLogin() {
	// The reply to the login packet will contain a 6 bytes long auth ID with the first 2 bytes set to our randID.
	var randID [2]byte
	_, err := rand.Read(randID[:])
	if err != nil {
		log.Fatal(err)
	}
	p.stream.send([]byte{0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00,
		byte(p.stream.localSID >> 24), byte(p.stream.localSID >> 16), byte(p.stream.localSID >> 8), byte(p.stream.localSID),
		byte(p.stream.remoteSID >> 24), byte(p.stream.remoteSID >> 16), byte(p.stream.remoteSID >> 8), byte(p.stream.remoteSID),
		0x00, 0x00, 0x00, 0x70, 0x01, 0x00, 0x00, byte(p.authInnerSendSeq),
		byte(p.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})
	p.authSendSeq++
	p.authInnerSendSeq++
}

func (p *controlStream) sendPktReauth(firstReauthSend bool) {
	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.stream.send([]byte{0x40, 0x00, 0x00, 0x00, 0x00, 0x00, byte(p.authSendSeq), byte(p.authSendSeq >> 8),
		byte(p.stream.localSID >> 24), byte(p.stream.localSID >> 16), byte(p.stream.localSID >> 8), byte(p.stream.localSID),
		byte(p.stream.remoteSID >> 24), byte(p.stream.remoteSID >> 16), byte(p.stream.remoteSID >> 8), byte(p.stream.remoteSID),
		0x00, 0x00, 0x00, 0x30, 0x01, magic, 0x00, byte(p.authInnerSendSeq),
		byte(p.authInnerSendSeq >> 8), 0x00, p.authID[0], p.authID[1], p.authID[2], p.authID[3], p.authID[4], p.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})
	p.authSendSeq++
	p.authInnerSendSeq++
	p.lastReauthAt = time.Now()
}

func (p *controlStream) SendDisconnect() {
	p.stream.send([]byte{0x40, 0x00, 0x00, 0x00, 0x00, 0x00, byte(p.stream.sendSeq), byte(p.stream.sendSeq >> 8),
		byte(p.stream.localSID >> 24), byte(p.stream.localSID >> 16), byte(p.stream.localSID >> 8), byte(p.stream.localSID),
		byte(p.stream.remoteSID >> 24), byte(p.stream.remoteSID >> 16), byte(p.stream.remoteSID >> 8), byte(p.stream.remoteSID),
		0x00, 0x00, 0x00, 0x30, 0x01, 0x01, 0x00, byte(p.authInnerSendSeq),
		byte(p.authInnerSendSeq >> 8), 0x00, p.authID[0], p.authID[1], p.authID[2], p.authID[3], p.authID[4], p.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})
	p.stream.send([]byte{0x10, 0x00, 0x00, 0x00, 0x05, 0x00, 0x00, 0x00,
		byte(p.stream.localSID >> 24), byte(p.stream.localSID >> 16), byte(p.stream.localSID >> 8), byte(p.stream.localSID),
		byte(p.stream.remoteSID >> 24), byte(p.stream.remoteSID >> 16), byte(p.stream.remoteSID >> 8), byte(p.stream.remoteSID)})
}

func (p *controlStream) sendRequestSerialAndAudio() {
	log.Print("requesting serial and audio stream")
	p.stream.send([]byte{0x90, 0x00, 0x00, 0x00, 0x00, 0x00, byte(p.authSendSeq), byte(p.authSendSeq >> 8),
		byte(p.stream.localSID >> 24), byte(p.stream.localSID >> 16), byte(p.stream.localSID >> 8), byte(p.stream.localSID),
		byte(p.stream.remoteSID >> 24), byte(p.stream.remoteSID >> 16), byte(p.stream.remoteSID >> 8), byte(p.stream.remoteSID),
		0x00, 0x00, 0x00, 0x80, 0x01, 0x03, 0x00, byte(p.authInnerSendSeq),
		byte(p.authInnerSendSeq >> 8), 0x00, p.authID[0], p.authID[1], p.authID[2], p.authID[3], p.authID[4], p.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, 0x64,
		0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
	p.authSendSeq++
	p.authInnerSendSeq++
}

func (p *controlStream) Start() {
	p.stream.open(50001)

	p.stream.sendPkt3()
	p.stream.sendSeq = 1
	p.sendPkt7(nil, p.stream.sendSeq)
	p.stream.sendSeq = 0
	p.stream.sendPkt3()

	// Expecting a Pkt4 answer.
	// Example answer from radio: 0x10, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x8c, 0x7d, 0x45, 0x7a, 0x1d, 0xf6, 0xe9, 0x0b
	r := p.stream.expect(16, []byte{0x10, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00})
	p.stream.remoteSID = binary.BigEndian.Uint32(r[8:12])

	log.Debugf("got remote session id %.8x", p.stream.remoteSID)

	p.authSendSeq = 1
	p.authInnerSendSeq = 0x50
	p.stream.sendPkt6()

	// Expecting a Pkt6 answer.
	r = p.stream.expect(16, []byte{0x10, 0x00, 0x00, 0x00, 0x06, 0x00, 0x01, 0x00})
	p.stream.remoteSID = binary.BigEndian.Uint32(r[8:12]) // TODO

	p.sendPktLogin()
	p.stream.sendSeq = 5

	// 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 = p.stream.expect(96, []byte{0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00})
	if bytes.Equal(r[48:52], []byte{0xff, 0xff, 0xff, 0xfe}) {
		log.Fatal("invalid user/password")
	}

	copy(p.authID[:], r[26:32])
	log.Print("auth ok")
	p.sendPktReauth(true)
	time.AfterFunc(time.Second*2, p.sendRequestSerialAndAudio)

	var lastPingAt time.Time
	var lastStatusLog time.Time
	var errCount int

	_, err := rand.Read(p.randIDByteForPktSeven[:])
	if err != nil {
		log.Fatal(err)
	}

	for {
		r, err := p.stream.read()
		if err != nil {
			errCount++
			if errCount > 5 {
				log.Fatal("timeout")
			}
			log.Error("stream break detected")
		}
		errCount = 0

		if len(r) == 21 && bytes.Equal(r[1:6], []byte{0x00, 0x00, 0x00, 0x07, 0x00}) {
			gotSeq := binary.LittleEndian.Uint16(r[6:8])
			if r[16] == 0x00 { // This is a pkt7 request from the radio.
				// Replying to the radio.
				// Example request from radio: 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x1c, 0x0e, 0xe4, 0x35, 0xdd, 0x72, 0xbe, 0xd9, 0xf2, 0x63, 0x00, 0x57, 0x2b, 0x12, 0x00
				// Example answer from PC:     0x15, 0x00, 0x00, 0x00, 0x07, 0x00, 0x1c, 0x0e, 0xbe, 0xd9, 0xf2, 0x63, 0xe4, 0x35, 0xdd, 0x72, 0x01, 0x57, 0x2b, 0x12, 0x00
				p.sendPkt7(r[17:21], gotSeq)
			} else {
				if p.expectedPkt7ReplySeq != gotSeq { // TODO
					var missingPkts int
					if gotSeq > p.expectedPkt7ReplySeq {
						missingPkts = int(gotSeq) - int(p.expectedPkt7ReplySeq)
					} else {
						missingPkts = int(gotSeq) + 65536 - int(p.expectedPkt7ReplySeq)
					}
					if missingPkts < 1000 {
						log.Error("lost ", missingPkts, " packets ", gotSeq, " ", p.expectedPkt7ReplySeq)
					}
				}
			}
		}
		if len(r) == 16 && 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.stream.send([]byte{0x10, 0x00, 0x00, 0x00, 0x00, 0x00, byte(gotSeq), byte(gotSeq >> 8),
				byte(p.stream.localSID >> 24), byte(p.stream.localSID >> 16), byte(p.stream.localSID >> 8), byte(p.stream.localSID),
				byte(p.stream.remoteSID >> 24), byte(p.stream.remoteSID >> 16), byte(p.stream.remoteSID >> 8), byte(p.stream.remoteSID)})
		}
		if len(r) == 80 && 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

			log.Error("reauth failed")
			p.SendDisconnect()
			os.Exit(1)
		}
		if len(r) == 144 && 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
			log.Print("serial and audio request success")
			go streams.audio.Start()
		}

		if time.Since(lastPingAt) >= 100*time.Millisecond {
			p.sendPkt7(nil, p.stream.sendSeq)
			p.stream.sendPkt3()
			p.stream.sendSeq++
			lastPingAt = time.Now()

			if time.Since(p.lastReauthAt) >= 60*time.Second {
				p.sendPktReauth(false)
			}

			if time.Since(lastStatusLog) >= 10*time.Second {
				log.Print("still connected")
				lastStatusLog = time.Now()
			}
		}
	}
}