package fibs

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"log"
	"math/rand"
	"regexp"
	"strconv"
	"strings"
	"time"

	"github.com/reiver/go-oi"
	"github.com/reiver/go-telnet"
	"golang.org/x/text/language"
	"golang.org/x/text/message"
	"nhooyr.io/websocket"
)

const debug = 1 // TODO

const whoInfoSize = 12

const (
	whoInfoDataName = iota
	whoInfoDataOpponent
	whoInfoDataWatching
	whoInfoDataReady
	whoInfoDataAway
	whoInfoDataRating
	whoInfoDataExperience
	whoInfoDataIdleTime
	whoInfoDataLoginTime
	whoInfoDataHostname
	whoInfoDataClientName
	whoInfoDataEmail
)

var DefaultProxyAddress = ""

var (
	TypeWelcome      = []byte("1")
	TypeOwnInfo      = []byte("2")
	TypeMOTD         = []byte("3")
	TypeEndMOTD      = []byte("4")
	TypeWhoInfo      = []byte("5")
	TypeEndWhoInfo   = []byte("6")
	TypeLogin        = []byte("7")
	TypeLogout       = []byte("8")
	TypeMsg          = []byte("9")
	TypeMsgDelivered = []byte("10")
	TypeMsgSaved     = []byte("11")
	TypeSay          = []byte("12")
	TypeShout        = []byte("13")
	TypeWhisper      = []byte("14")
	TypeKibitz       = []byte("15")
	TypeYouSay       = []byte("16")
	TypeYouShout     = []byte("17")
	TypeYouWhisper   = []byte("18")
	TypeYouKibitz    = []byte("19")
	TypeBoardState   = []byte("board:")
)

var numberPrinter = message.NewPrinter(language.English)

type WhoInfo struct {
	Username   string
	Opponent   string
	Watching   string
	Ready      bool
	Away       bool
	Rating     int
	Experience int
	Idle       int
	LoginTime  int
	ClientName string
}

func (w *WhoInfo) String() string {
	opponent := "In the lobby"
	if w.Opponent != "" && w.Opponent != "-" {
		opponent = "playing against " + w.Opponent
	}
	clientName := ""
	if w.ClientName != "" && w.ClientName != "-" {
		clientName = " using " + w.ClientName
	}
	return fmt.Sprintf("%s (rated %d with %d exp) is %s%s", w.Username, w.Rating, w.Experience, opponent, clientName)
}

type Client struct {
	In    chan []byte
	Out   chan []byte
	Event chan interface{}

	Username string
	Password string

	loggedin bool
	motd     []byte
	rawMode  bool

	who map[string]*WhoInfo

	notified map[string]bool

	serverAddress  string
	wsProxyAddress string // WebSocket->TCP proxy address

	tcpConn io.Writer
	wsConn  *websocket.Conn

	Board *Board

	tvMode bool
}

func NewClient(serverAddress string, username string, password string) *Client {
	c := &Client{
		In:    make(chan []byte, 100),
		Out:   make(chan []byte, 100),
		Event: make(chan interface{}, 100),

		serverAddress:  serverAddress,
		wsProxyAddress: DefaultProxyAddress,

		Username: username,
		Password: password,

		who: make(map[string]*WhoInfo),

		notified: make(map[string]bool),
	}

	c.Board = NewBoard(c)

	go c.eventLoop()

	return c
}

func (c *Client) handleWrite() {
	var buffer bytes.Buffer
	var p []byte

	var crlfBuffer [2]byte = [2]byte{'\r', '\n'}
	crlf := crlfBuffer[:]

	help := []byte("help")
	who := []byte("who")
	quit := []byte("quit")
	bye := []byte("bye")
	watch := []byte("watch")
	tv := []byte("tv")
	reset := []byte("reset")
	about := []byte("about")
	show := []byte("show")
	average := []byte("average")
	dicetest := []byte("dicetest")
	boardstate := []byte("boardstate")
	stat := []byte("stat")
	for b := range c.Out {
		if bytes.Equal(bytes.ToLower(b), watch) {
			c.WatchRandomGame()
			continue
		} else if bytes.Equal(bytes.ToLower(b), tv) {
			c.tvMode = !c.tvMode
			if c.tvMode {
				l("Now watching backgammon TV")
				c.WatchRandomGame()
			} else {
				l("Stopped watching backgammon TV")
			}
			continue
		} else if bytes.Equal(bytes.ToLower(b), reset) {
			c.Board.ResetPreMoves()
			c.Event <- &EventDraw{}
			l("Reset pre-moves")
			continue
		} else if bytes.Equal(bytes.ToLower(b), who) {
			for username := range c.who {
				lf("%s", c.who[username])
			}
			continue
		} else if bytes.HasPrefix(bytes.ToLower(b), help) || bytes.HasPrefix(bytes.ToLower(b), about) || bytes.HasPrefix(bytes.ToLower(b), average) ||
			bytes.HasPrefix(bytes.ToLower(b), dicetest) || bytes.HasPrefix(bytes.ToLower(b), show) || bytes.HasPrefix(bytes.ToLower(b), stat) {
			c.rawMode = true
			go func() {
				time.Sleep(time.Second)
				c.rawMode = false
			}()
		} else if bytes.Equal(bytes.ToLower(b), boardstate) {
			homeBoardStart, homeBoardEnd := c.Board.homeBoardSpaces()

			lf("Board state:  %s", c.Board.GetState())
			lf("Player color:  %d", c.Board.v[StatePlayerColor])
			lf("Direction:  %d", c.Board.v[StateDirection])
			lf("Current turn:  %d", c.Board.v[StateTurn])
			lf("Player home spaces:  %d-%d",
				homeBoardStart, homeBoardEnd)
			lf("Player can bear off:  %t", c.Board.allPlayerPiecesInHomeBoard())
			lf("Moves:  %+v", c.Board.moves)
			lf("Pre-moves:  %+v", c.Board.premove)
			continue
		} else if bytes.Equal(bytes.ToLower(b), quit) || bytes.Equal(bytes.ToLower(b), bye) {
			// TODO match command, not exact string
			c.rawMode = true
		}

		if debug > 0 {
			l("-> " + string(bytes.TrimSpace(b)))
		}

		buffer.Write(b)
		buffer.Write(crlf)

		p = buffer.Bytes()

		if c.wsProxyAddress != "" {
			err := c.wsConn.Write(context.Background(), websocket.MessageBinary, p)
			if err != nil {
				log.Fatalf("Transmission problem: %s", err)
			}
			buffer.Reset()
			continue
		}

		n, err := oi.LongWrite(c.tcpConn, p)
		if nil != err {
			break
		}
		if expected, actual := int64(len(p)), n; expected != actual {
			log.Fatalf("Transmission problem: tried sending %d bytes, but actually only sent %d bytes.", expected, actual)
		}

		buffer.Reset()
	}
}

func (c *Client) handleRead(r io.Reader) {
	var b = &bytes.Buffer{}
	var buffer [1]byte // Seems like the length of the buffer needs to be small, otherwise will have to wait for buffer to fill up.
	p := buffer[:]

	var motd bool // Parse all messages as MOTD text until MsgEndMOTD

	for {
		// Read 1 byte.
		n, err := r.Read(p)
		if n <= 0 && nil == err {
			continue
		} else if n <= 0 && nil != err {
			if err.Error() != "EOF" {
				lf("** Disconnected: %s", err)
			} else {
				l("** Disconnected")
			}
			return
		}

		b.WriteByte(p[0])

		if p[0] == '\n' {
			buf := make([]byte, b.Len())
			copy(buf, b.Bytes())

			if debug > 0 {
				l("<- " + string(bytes.TrimSpace(buf)))
			}

			if c.loggedin {
				if !motd {
					buf = bytes.TrimSpace(buf)
					if len(buf) == 0 {
						b.Reset()
						continue
					}
				}

				if c.rawMode {
					c.In <- append([]byte("** "), buf...)
					b.Reset()
					continue
				}

				if bytes.HasPrefix(b.Bytes(), TypeMOTD) && !motd {
					motd = true
					c.motd = append(c.motd, buf[1:]...)
					b.Reset()
					continue
				} else if bytes.HasPrefix(b.Bytes(), TypeEndMOTD) && motd {
					motd = false
					c.motd = bytes.TrimSpace(c.motd)
					c.In <- append([]byte("3 "), c.motd...)
					b.Reset()
					continue
				} else if motd {
					c.motd = append(c.motd, buf...)
					b.Reset()
					continue
				}

				c.In <- buf
			}
			b.Reset()
		}

		if !c.loggedin {
			bt := strings.TrimSpace(b.String())
			if bt == "login:" {
				b.Reset()
				c.Out <- []byte(fmt.Sprintf("login bgammon 1008 %s %s", c.Username, c.Password))
				c.loggedin = true
			}
		}
	}
}

// CallTELNET is called when a connection is made with the server.
func (c *Client) CallTELNET(ctx telnet.Context, w telnet.Writer, r telnet.Reader) {
	c.tcpConn = w

	go c.handleRead(r)

	c.handleWrite()
}

func (c *Client) keepAlive() {
	t := time.NewTicker(5 * time.Minute)
	for range t.C {
		c.Out <- []byte("set boardstyle 3")
	}
}

func (c *Client) updateWhoInfo(b []byte) {
	s := bytes.Split(b, []byte(" "))
	if len(s) != whoInfoSize {
		return
	}

	info := &WhoInfo{
		Username: string(s[whoInfoDataName]),
	}

	r := s[whoInfoDataRating]
	if bytes.ContainsRune(r, '.') {
		r = s[whoInfoDataRating][:bytes.IndexByte(s[whoInfoDataRating], '.')]
	}
	rating, err := strconv.Atoi(string(r))
	if err != nil {
		rating = 0
	}
	info.Rating = rating

	experience, err := strconv.Atoi(string(s[whoInfoDataExperience]))
	if err != nil {
		experience = 0
	}
	info.Experience = experience

	opponent := ""
	if len(s[whoInfoDataOpponent]) > 1 || s[whoInfoDataOpponent][0] != '-' {
		opponent = string(s[whoInfoDataOpponent])
	}
	info.Opponent = opponent

	watching := ""
	if len(s[whoInfoDataWatching]) > 1 || s[whoInfoDataWatching][0] != '-' {
		watching = string(s[whoInfoDataWatching])
	}
	info.Watching = watching

	ready := false
	if string(s[whoInfoDataReady]) == "1" {
		ready = true
	}
	info.Ready = ready

	clientName := ""
	if len(s[whoInfoDataClientName]) > 1 || s[whoInfoDataClientName][0] != '-' {
		clientName = string(s[whoInfoDataClientName])
	}
	info.ClientName = clientName

	status := "Unavailable"
	if info.Opponent != "" {
		status = "vs. " + info.Opponent
	} else if info.Ready {
		status = "Available"
	}

	itemText := info.Username + strings.Repeat(" ", 18-len(info.Username))

	ratingString := numberPrinter.Sprintf("%d", info.Rating)
	itemText += ratingString + strings.Repeat(" ", 8-len(ratingString))

	experienceString := numberPrinter.Sprintf("%d", info.Experience)
	itemText += experienceString + strings.Repeat(" ", 12-len(experienceString))

	itemText += status

	c.who[string(s[whoInfoDataName])] = info

	// TODO who info event
}

func (c *Client) GetAllWhoInfo() []*WhoInfo {
	w := make([]*WhoInfo, len(c.who))
	var i int
	for _, whoInfo := range c.who {
		w[i] = whoInfo
		i++
	}
	return w
}

func (c *Client) LoggedIn() bool {
	// TODO lock
	return c.loggedin
}

func (c *Client) WatchRandomGame() {
	var options []string
	for username, whoInfo := range c.who {
		if username != "" && whoInfo.Opponent != "" &&
			!strings.Contains(username, "Bot") && !strings.Contains(whoInfo.Opponent, "Bot") {
			options = append(options, username, whoInfo.Opponent)
		}
	}
	if len(options) == 0 {
		for username, whoInfo := range c.who {
			if username != "" && whoInfo.Opponent != "" {
				options = append(options, username, whoInfo.Opponent)
			}
		}
		if len(options) == 0 {
			return
		}
	}

	option := options[rand.Intn(len(options))]
	c.Out <- []byte("watch " + option)
}

func (c *Client) callWebSocket() {
	ctx := context.Background()

	var err error
	c.wsConn, _, err = websocket.Dial(ctx, c.wsProxyAddress, nil)
	if err != nil {
		log.Fatal("dial error", err)
	}
	defer c.wsConn.Close(websocket.StatusInternalError, "the sky is falling")

	//c.wsConn.Close(websocket.StatusNormalClosure, "")

	r, w := io.Pipe()

	go c.handleRead(r)

	go func() {
		for {
			_, data, err := c.wsConn.Read(context.Background())
			if err != nil {
				if err.Error() != "EOF" {
					lf("** Disconnected: %s", err)
				} else {
					l("** Disconnected")
				}
			}
			w.Write(data)
		}
	}()

	c.handleWrite()
	/* TODO
	err := conn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
	if err != nil {
		log.Println("write close:", err)
		return nil
	}
	select {
	case <-done:
	case <-time.After(time.Second):
	}*/
}

func (c *Client) Connect() error {
	connectionType := "Telnet"
	if c.wsProxyAddress != "" {
		connectionType = fmt.Sprintf("WebSocket proxy (%s)", c.wsProxyAddress)
	}
	l(fmt.Sprintf("Connecting via %s to %s...", connectionType, c.serverAddress))

	go c.keepAlive()

	if c.wsProxyAddress != "" {
		go c.callWebSocket()
		return nil
	}

	err := telnet.DialToAndCall(c.serverAddress, c)
	if err != nil {
		lf("** Disconnected: %s", err)
	}
	return err
}

func (c *Client) eventLoop() {
	var setBoardStyle bool
	var turnRegexp = regexp.MustCompile(`^turn: (\w+)\.`)
	var movesRegexp = regexp.MustCompile(`^(\w+) moves (.*)`)
	var rollsRegexp = regexp.MustCompile(`^(\w+) rolls? (.*)`)
	var logInOutRegexp = regexp.MustCompile(`^\w+ logs [In|Out]\.`)
	var dropsConnection = regexp.MustCompile(`^\w+ drops connection\.`)
	var startMatchRegexp = regexp.MustCompile(`^\w+ and \w+ start a .*`)
	var winsMatchRegexp = regexp.MustCompile(`^\w+ wins a [0-9]+ point match against .*`)
	var winsThisMatchRegexp = regexp.MustCompile(`^\w+ wins the [0-9]+ point match .*`)
	var newGameRegexp = regexp.MustCompile(`^Starting a new game with .*`)

	var gameBufferRegexp = regexp.MustCompile(`^\w+ (makes|roll|rolls|rolled|move|moves) .*`)
	var pleaseMoveRegexp = regexp.MustCompile(`^Please move ([0-9]) pieces?.`)
	var cantMoveRegexp = regexp.MustCompile(`^(\w+) can't move.`)
	var doublesRegexp = regexp.MustCompile(`^\w+ doubles.`)
	var acceptDoubleRegexp = regexp.MustCompile(`^\w+ accepts the double.`)

	for b := range c.In {
		b = bytes.Replace(b, []byte{7}, []byte{}, -1)
		b = bytes.TrimSpace(b)
		bl := bytes.ToLower(b)

		// Select 10+ first to read prefixes correctly
		if bytes.HasPrefix(b, TypeMsgSaved) {
			lf("Message to %s saved", b[3:])
			continue
		} else if bytes.HasPrefix(b, TypeMsgDelivered) {
			lf("Message to %s delivered", b[3:])
			continue
		} else if bytes.HasPrefix(b, TypeSay) {
			s := bytes.SplitN(b[3:], []byte(" "), 2)
			lf("%s says: %s", s[0], s[1])
			continue
		} else if bytes.HasPrefix(b, TypeShout) {
			s := bytes.SplitN(b[3:], []byte(" "), 2)
			lf("%s shouts: %s", s[0], s[1])
			continue
		} else if bytes.HasPrefix(b, TypeWhisper) {
			s := bytes.SplitN(b[3:], []byte(" "), 2)
			lf("%s whispers: %s", s[0], s[1])
			continue
		} else if bytes.HasPrefix(b, TypeKibitz) {
			s := bytes.SplitN(b[3:], []byte(" "), 2)
			lf("%s kibitzes: %s", s[0], s[1])
			continue
		} else if bytes.HasPrefix(b, TypeYouSay) {
			s := bytes.SplitN(b[3:], []byte(" "), 2)
			lf("You say to %s: %s", s[0], s[1])
			continue
		} else if bytes.HasPrefix(b, TypeYouShout) {
			lf("You shout: %s", b[3:])
			continue
		} else if bytes.HasPrefix(b, TypeYouWhisper) {
			lf("You whisper: %s", b[3:])
			continue
		} else if bytes.HasPrefix(b, TypeYouKibitz) {
			lf("You kibitz: %s", b[3:])
			continue
		} else if bytes.HasPrefix(b, TypeWelcome) {
			s := bytes.Split(b[2:], []byte(" "))
			loginTimestamp, err := strconv.Atoi(string(s[1]))
			if err != nil {
				loginTimestamp = 0
			}
			loginTime := time.Unix(int64(loginTimestamp), 0)
			lf("Welcome, %s! Last login at %s", s[0], loginTime)
			continue
		} else if bytes.HasPrefix(b, TypeOwnInfo) {
			// TODO Print own info
			continue
		} else if bytes.HasPrefix(b, TypeMOTD) {
			for _, line := range bytes.Split(c.motd, []byte("\n")) {
				l(string(line))
			}
			if !setBoardStyle {
				c.Out <- []byte("set boardstyle 3")
				setBoardStyle = true
			}
			continue
		} else if bytes.HasPrefix(b, TypeWhoInfo) {
			c.updateWhoInfo(b[2:])
			// TODO who window
			continue
		} else if bytes.HasPrefix(b, TypeEndWhoInfo) {
			// TODO draw who info event
			continue
		} else if bytes.HasPrefix(b, TypeLogin) || bytes.HasPrefix(b, TypeLogout) {
			b = b[2:]
			b = b[bytes.IndexByte(b, ' ')+1:]
			l(string(b))
			// TODO enable showing log In and Out messages
			// TODO remove from who
			continue
		} else if bytes.HasPrefix(b, TypeMsg) {
			lf("Received message: %s", b[3:])
			continue
		} else if bytes.HasPrefix(b, TypeBoardState) {
			c.Board.SetState(string(bytes.SplitN(b, []byte(" "), 2)[0][6:]))
			c.Event <- &EventBoardState{S: c.Board.s, V: c.Board.v}
			continue
		} else if turnRegexp.Match(b) {
			turn := turnRegexp.FindSubmatch(b)
			if string(turn[1]) == c.Username || string(turn[1]) == c.Board.s[0] || string(turn[1]) == "You" {
				c.Board.v[StateTurn] = c.Board.v[StatePlayerColor]
			} else {
				c.Board.v[StateTurn] = c.Board.v[StatePlayerColor] * -1
			}
		} else if rollsRegexp.Match(b) {
			roll := rollsRegexp.FindSubmatch(b)
			periodIndex := bytes.IndexRune(roll[2], '.')
			if periodIndex > -1 {
				roll[2] = roll[2][:periodIndex]
			}
			s := bytes.Split(roll[2], []byte(" "))
			var dice [2]int
			var i int
			for _, m := range s {
				v, err := strconv.Atoi(string(m))
				if err == nil {
					dice[i] = v
					i++
				}
			}

			if string(roll[1]) == c.Board.s[0] || string(roll[1]) == "You" {
				c.Board.v[StateTurn] = c.Board.v[StatePlayerColor]
				c.Board.v[StatePlayerDice1] = dice[0]
				c.Board.v[StatePlayerDice2] = dice[1]
			} else {
				c.Board.v[StateTurn] = c.Board.v[StatePlayerColor] * -1
				c.Board.v[StateOpponentDice1] = dice[0]
				c.Board.v[StateOpponentDice2] = dice[1]
			}

			c.Event <- &EventBoardState{S: c.Board.s, V: c.Board.v}

			c.Board.ResetMoves()

			c.Board.Draw()
		} else if movesRegexp.Match(b) {
			match := movesRegexp.FindSubmatch(b)

			player := c.Board.v[StatePlayerColor]
			if string(match[1]) == c.Board.s[1] {
				player *= -1
			}

			c.Board.ResetMoves()

			from := -1
			to := -1

			s := bytes.Split(match[2], []byte(" "))
			for _, m := range s {
				move := bytes.Split(m, []byte("-"))
				if len(move) == 2 {
					from = c.Board.parseMoveString(player, string(move[0]))
					to = c.Board.parseMoveString(player, string(move[1]))
					if from >= 0 && to >= 0 {
						c.Event <- &EventMove{
							Player: player,
							From:   from,
							To:     to,
						}
					}

					c.Board.Move(player, string(move[0]), string(move[1]))
				}
			}

			c.Board.SimplifyMoves()
			c.Board.Draw()

			bs := string(b)
			if strings.HasSuffix(bs, " .") {
				bs = bs[:len(bs)-2] + "."
			}
			lg(bs)
			continue
		} else if string(b) == "Value of 'boardstyle' set to 3." {
			continue
		} else if string(b) == "It's your turn to move." || strings.TrimSpace(string(b)) == "It's your turn to roll or double." || strings.TrimSpace(string(b)) == "It's your turn. Please roll or double" {
			c.Board.v[StateTurn] = c.Board.v[StatePlayerColor]
			c.Board.Draw()
			if strings.TrimSpace(string(b)) == "It's your turn to roll or double." || strings.TrimSpace(string(b)) == "It's your turn. Please roll or double" {
				c.Out <- []byte("roll") // TODO Delay and allow configuring
			}
		} else if cantMoveRegexp.Match(b) {
			match := cantMoveRegexp.FindSubmatch(b)

			u := string(match[1])
			if u == c.Username || u == c.Board.s[0] || u == "You" {
				//c.Board.opponentDice[0] = 0
				//c.Board.opponentDice[1] = 0
				c.Board.v[StateTurn] = c.Board.v[StatePlayerColor] * -1
			} else if u == c.Board.s[1] {
				//c.Board.playerDice[0] = 0
				//c.Board.playerDice[1] = 0
				c.Board.v[StateTurn] = c.Board.v[StatePlayerColor]
			}
		} else if pleaseMoveRegexp.Match(b) {
			match := pleaseMoveRegexp.FindSubmatch(b)

			n, err := strconv.Atoi(string(match[1]))
			if err == nil {
				c.Board.v[StateMovablePieces] = n
			}
		} else if bytes.HasPrefix(bl, []byte("you're now watching")) {
			// Board state is not sent automatically when watching
			c.Out <- []byte("board")
		} else if logInOutRegexp.Match(b) {
			continue
		} else if dropsConnection.Match(b) {
			continue
		} else if startMatchRegexp.Match(b) {
			continue
		} else if winsThisMatchRegexp.Match(b) {
			if c.tvMode {
				go func() {
					time.Sleep(5 * time.Second)
					if !c.tvMode {
						return
					}
					c.WatchRandomGame()
				}()
			}
			continue
		} else if winsMatchRegexp.Match(b) {
			continue
		} else if newGameRegexp.Match(b) {
			c.Board.ResetMoves()
			c.Board.resetSelection()
			// TODO reset premove
			continue
		}

		if gameBufferRegexp.Match(b) || cantMoveRegexp.Match(b) ||
			doublesRegexp.Match(b) || acceptDoubleRegexp.Match(b) ||
			bytes.HasPrefix(bl, []byte("you're now watching")) || bytes.HasPrefix(bl, []byte("** you stop watching")) ||
			strings.HasPrefix(string(b), "Bearing off:") || strings.HasPrefix(string(b), "The only possible move") {
			lg(string(b))

			if !bytes.HasPrefix(bl, []byte("you're now watching")) && !bytes.HasPrefix(bl, []byte("** you stop watching")) {
				continue
			}
		}

		l(string(b))
	}
}