// vim:ts=4:sts=4:sw=4:noet:tw=72

package ircd

import (
	"fmt"
	"net"
	"os"
	"runtime"
	"strings"
	"time"

	"code.dnix.de/an/conf"
	"code.dnix.de/an/irc"
	"code.dnix.de/an/xlog"
)

const (
	CHANLIMIT  = 1024
	CHANNELLEN = 200
	TOPICLEN   = 1024
)

var myinfo string = "%s %s/%s * *"
var isupport string = "ALIAS FRIEND UNFRIEND CASEMAPPING=rfc1459 CHANLIMIT=#:1024 CHANMODES=b,k,l,imnpst CHANNELLEN=200 CHANTYPES=# EXCEPTS=e KICKLEN MAXLIST=b:50,e:50 MODES=1 NETWORK=dnix.de NICKLEN=32 PREFIX=(aohv)&@%%+ SAFELIST STATUSMSG=&@%%+ TOPICLEN"

type Server struct {
	Dispatch  chan *irc.Message
	AddClient chan Client
	DelClient chan Client

	host     string
	info     string
	software string
	version  string
	created  string
	motd     string
	clients  map[string]Client
	chUsers  map[string]map[string]string
	//chModes    map[string][]string
	chTopics   map[string]string
	config     *conf.ConfigFile
	configPath string

	packetsTransferred float64
	connectionsCurrent float64
	connectionsCount   float64
	queueLen           float64
}

// Create a new server instance.
func NewServer(configPath, software, version string) *Server {
	sv := &Server{software: software, version: version, created: "yes"}

	sv.Dispatch = make(chan *irc.Message, 1024)
	sv.AddClient = make(chan Client, 1024)
	sv.DelClient = make(chan Client, 1024)

	sv.clients = make(map[string]Client)
	sv.chUsers = make(map[string]map[string]string)
	sv.chTopics = make(map[string]string)
	sv.configPath = configPath
	sv.loadConfig()
	loglevel, _ := sv.config.GetInt("system", "loglevel")
	sv.host, _ = sv.config.GetString("server", "host")
	sv.info, _ = sv.config.GetString("server", "info")
	sv.motd, _ = sv.config.GetString("server", "motd")
	xlog.Init(loglevel)

	sv.packetsTransferred = 0
	sv.connectionsCurrent = 0
	sv.connectionsCount = 0
	sv.queueLen = 0

	return sv
}

// Open the listening port and start the main server loop.
func (sv *Server) Run() {
	xlog.Info("%s/%s", sv.software, sv.version)
	go monitoringRun(sv)
	laddr, err := sv.config.GetString("net", "listen")
	if err == nil {
		go sv.listen(laddr)
	}
	laddr, err = sv.config.GetString("net", "listen_tls")
	if err == nil {
		go sv.listenTls(laddr)
	}
	sv.dispatch()
}

func (sv *Server) listen(laddr string) {
	listen, err := net.Listen("tcp", laddr)
	if err != nil {
		xlog.Fatal(err.Error())
		os.Exit(-1)
	}
	for {
		time.Sleep(1 * time.Millisecond)
		conn, err := listen.Accept()
		if err != nil {
			xlog.Error(err.Error())
		} else {
			NewRemoteClient(sv, conn)
			sv.connectionsCount++
		}
	}
}

func (sv *Server) listenTls(laddr string) {
}

func (sv *Server) dispatch() {
	for {
		time.Sleep(1 * time.Microsecond)
		sv.queueLen = float64(len(sv.Dispatch))
		select {
		case msg := <-sv.Dispatch:
			sv.recvMsg(msg)
			sv.packetsTransferred++
		case cl := <-sv.AddClient:
			lnick := strings.ToLower(cl.Name())
			if _, exists := sv.clients[lnick]; exists {
				cl.Register(false)
				xlog.Info("Client registration failed: '%s'", lnick)
			} else {
				sv.clients[lnick] = cl
				sv.sendLogon(lnick)
				sv.connectionsCurrent = float64(len(sv.clients))
				cl.Register(true)
				xlog.Info("Client registered: '%s'", lnick)
				xlog.Info("Server has %d client(s)", len(sv.clients))
				xlog.Debug("Goroutines running: %d", runtime.NumGoroutine())
			}
		case cl := <-sv.DelClient:
			nick := cl.Name()
			lnick := strings.ToLower(nick)
			cl.Destroy()
			for chname, ch := range sv.chUsers {
				if _, exists := ch[lnick]; exists {
					delete(ch, lnick)
					sv.sendMsg(irc.M(nick, "PART", chname, "quit"))
				}
			}
			delete(sv.clients, lnick)
			sv.connectionsCurrent = float64(len(sv.clients))
			xlog.Info("Client deleted: '%s'", lnick)
			xlog.Info("Server has %d client(s)", len(sv.clients))
			xlog.Debug("Goroutines running: %d", runtime.NumGoroutine())
		default:
		}
	}
}

func (sv *Server) loadConfig() {
	cfg, err := conf.ReadConfigFile(sv.configPath)
	if err != nil {
		xlog.Fatal("Can't read config file (%s)", err.Error())
		os.Exit(-1)
	}
	sv.config = cfg
}

func (sv *Server) recvMsg(msg *irc.Message) {
	cmd := msg.Cmd
	hook, exists := svCommandHooks[cmd]
	if !exists {
		sv.sendReply(msg.Pre, ERR_UNKNOWNCOMMAND, cmd, "Unknown command")
		return
	}
	argc := len(msg.Args)
	if argc < hook.MinArgs {
		sv.sendReply(msg.Pre, ERR_NEEDMOREPARAMS, cmd, "Not enough parameters")
		return
	}
	if hook.NeedTrail && msg.Trail == "" {
		sv.sendReply(msg.Pre, ERR_NEEDMOREPARAMS, cmd, "Not enough parameters")
		return
	}
	hook.HookFn(sv, msg)
}

func (sv *Server) sendMsg(msg *irc.Message) {
	if strings.HasPrefix(msg.Args[0], "#") {
		lch := strings.ToLower(msg.Args[0])
		if _, exists := sv.chUsers[lch]; !exists {
			sv.sendReply(msg.Pre, ERR_NOSUCHNICK, msg.Args[0], "No such nick/channel")
			return
		}
		for lnick, _ := range sv.chUsers[lch] {
			if strings.ToLower(msg.Pre) == lnick && msg.Cmd == "PRIVMSG" {
				continue
			}
			if cl, exists := sv.clients[lnick]; exists {
				cl.Receive(msg)
			}
		}
	} else {
		lnick := strings.ToLower(msg.Args[0])
		if _, exists := sv.clients[lnick]; !exists {
			sv.sendReply(msg.Pre, ERR_NOSUCHNICK, msg.Args[0], "No such nick/channel")
			return
		}
		cl := sv.clients[lnick]
		cl.Receive(msg)
	}
}

func (sv *Server) sendReply(tar, cmd, args, trail string) {
	lnick := strings.ToLower(tar)
	if _, exists := sv.clients[lnick]; !exists {
		return
	}
	cl := sv.clients[lnick]
	if args != "" {
		args = tar + " " + args
	} else {
		args = tar
	}
	cl.Receive(irc.M(sv.host, cmd, args, trail))
}

func (sv *Server) sendLogon(nick string) {
	sv.sendReply(nick, RPL_WELCOME, "", "Willkommen!")
	sv.sendReply(nick, RPL_YOURHOST, "",
		fmt.Sprintf("Your host is %s, running on %s/%s",
			sv.host, sv.software, sv.version))
	sv.sendReply(nick, RPL_CREATED, "",
		fmt.Sprintf("Created: %s", sv.created))
	sv.sendReply(nick, RPL_MYINFO, "",
		fmt.Sprintf(myinfo, sv.host, sv.software, sv.version))
	sv.sendReply(nick, RPL_ISUPPORT, "",
		isupport+" are supported by this server")
	sv.sendReply(nick, RPL_MOTDSTART, "",
		fmt.Sprintf("- %s Message of the day -", sv.host))
	for _, line := range strings.Split(sv.motd, "\n") {
		sv.sendReply(nick, RPL_MOTD, "", fmt.Sprintf("- %s", line))
	}
	sv.sendReply(nick, RPL_ENDOFMOTD, "", "End of MOTD command")
}

func (sv *Server) channelJoin(nick, ch string) {
	lnick := strings.ToLower(nick)
	lch := strings.ToLower(ch)
	if _, exists := sv.chUsers[lch]; !exists {
		sv.chUsers[lch] = make(map[string]string)
		sv.chTopics[lch] = ""
	}
	if _, exists := sv.chUsers[lch][lnick]; exists {
		return
	}
	sv.chUsers[lch][lnick] = ""
	sv.sendMsg(irc.M(nick, "JOIN", ch, ""))
	sv.sendReply(nick, RPL_TOPIC, ch, sv.chTopics[ch])
	sv.channelNames(nick, ch)
}

func (sv *Server) channelPart(nick, ch, reason string) {
	lnick := strings.ToLower(nick)
	lch := strings.ToLower(nick)
	if _, exists := sv.chUsers[lch]; !exists {
		return
	}
	if _, exists := sv.chUsers[lch][lnick]; !exists {
		return
	}
	sv.sendMsg(irc.M(nick, "PART", ch, reason))
	delete(sv.chUsers[lch], lnick)
}

func (sv *Server) channelNames(nick, ch string) {
	lch := strings.ToLower(ch)
	if _, exists := sv.chUsers[lch]; !exists {
		return
	}
	names := ""
	for lnick, mode := range sv.chUsers[lch] {
		nick := sv.clients[lnick].Name()
		if names != "" {
			names += " "
		}
		names = names + mode + nick
	}
	sv.sendReply(nick, RPL_NAMEREPLY, "= "+ch, names)
	sv.sendReply(nick, RPL_ENDOFNAMES, ch, "End of /NAMES list")
}

type commandHook struct {
	HookFn    func(sv *Server, msg *irc.Message)
	MinArgs   int
	NeedTrail bool
	NeedOper  bool
	NeedAuth  bool
}

var svCommandHooks = map[string]commandHook{
	"PRIVMSG": {handleCmdPrivmsg, 1, true, false, false},
	"JOIN":    {handleCmdJoin, 1, false, false, false},
	"PART":    {handleCmdPart, 1, false, false, false},
	"QUIT":    {handleCmdQuit, 0, false, false, false},
	"MODE":    {handleCmdMode, 1, false, false, false},
	"TOPIC":   {handleCmdTopic, 1, false, false, false},
	"NAMES":   {handleCmdNames, 1, false, false, false},
	"WHOIS":   {handleCmdWhois, 0, false, false, false},
	"PING":    {handleCmdPing, 1, false, false, false},
	"REHASH":  {handleCmdRehash, 0, false, false, false},
	/*
		"LIST":     {handleCmdList, 0, false, false},
		"VERSION":  {handleCmdVersion, 0, false, false},
		"STATS":    {handleCmdStats, 0, false, false},
		"TIME":     {handleCmdTime, 0, false, false},
		"OPER":     {handleCmdOper, 1, false, false},
		"ADMIN":    {handleCmdAdmin, 0, false, false},
		"INFO":     {handleCmdInfo, 0, false, false},
		"WHO":      {handleCmdWho, 0, false, false},
		"WHOWAS":   {handleCmdWhowas, 0, false, false},
		"KILL":     {handleCmdKill, 0, false, false},
		"PONG":     {handleCmdPong, 0, false, false},
		"ERROR":    {handleCmdError, 0, false, false},
		"AWAY":     {handleCmdAway, 0, false, false},
		"RESTART":  {handleCmdRestart, 0, false, false},
		"SUMMON":   {handleCmdSummon, 0, false, false},
		"USERS":    {handleCmdUsers, 0, false, false},
		"USERHOST": {handleCmdUserhost, 0, false, false},
		"ISON":     {handleCmdIson, 0, false, false},
	*/
}

func handleCmdPrivmsg(sv *Server, msg *irc.Message) {
	sv.sendMsg(msg)
}

func handleCmdJoin(sv *Server, msg *irc.Message) {
	sv.channelJoin(msg.Pre, msg.Args[0])
}

func handleCmdPart(sv *Server, msg *irc.Message) {
	sv.channelPart(msg.Pre, msg.Args[0], msg.Trail)
}

func handleCmdQuit(sv *Server, msg *irc.Message) {

}

func handleCmdMode(sv *Server, msg *irc.Message) {

}

func handleCmdTopic(sv *Server, msg *irc.Message) {
	ch := msg.Args[0]
	if _, exists := sv.chUsers[ch]; !exists {
		sv.sendReply(msg.Pre, ERR_NOSUCHCHANNEL, ch, "No such channel")
	}
	if msg.Trail == "" {
		sv.sendReply(msg.Pre, RPL_TOPIC, ch, sv.chTopics[ch])
	} else {
		sv.chTopics[ch] = msg.Trail
		sv.sendMsg(msg)
		//sv.sendReply(msg.Pre, RPL_TOPIC, ch, msg.Trail)
	}
}

func handleCmdNames(sv *Server, msg *irc.Message) {
	ch := msg.Args[0]
	if _, exists := sv.chUsers[ch]; !exists {
		sv.sendReply(msg.Pre, ERR_NOSUCHCHANNEL, ch, "No such channel")
	}
	sv.channelNames(msg.Pre, ch)
}

func handleCmdWhois(sv *Server, msg *irc.Message) {
	sv.sendReply(msg.Pre, RPL_WHOISUSER, "nick user host *", "real name")
}

func handleCmdPing(sv *Server, msg *irc.Message) {
	sv.sendReply(msg.Pre, "PONG", msg.Args[0], "")
}

func handleCmdRehash(sv *Server, msg *irc.Message) {
	sv.loadConfig()
	sv.sendReply(msg.Pre, RPL_REHASHING, "", "Rehashing.")
	xlog.Info("Rehashing")
}