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

package main

import (
	"fmt"
	"net"
	"os"
	"runtime"
	"strconv"
	"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 flagConfig string

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 ControlMsg struct {
	Opcode int
	Client *Client
}

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
	subscriptions map[string][]string
	ports         map[int]bool
	config        *conf.ConfigFile
	configPath    string
}

func init() {
}

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

	srv.Dispatch = make(chan *irc.Message, 1024)
	srv.AddClient = make(chan *Client, 1024)
	srv.DelClient = make(chan *Client, 1024)
	srv.Host = "dnix.de"

	srv.clients = make(map[string]*Client)
	srv.subscriptions = make(map[string][]string)
	srv.info = ""
	srv.motd = `foo bar baz.`
	srv.configPath = configPath
	srv.loadConfig()
	loglevel, _ := srv.config.GetInt("system", "loglevel")
	xlog.Init(loglevel)

	return srv
}

// Open the listening port and start the main server loop.
func (srv *Server) Run() {
	xlog.Info("%s/%s", srv.software, srv.version)
	srv.Host, _ = srv.config.GetString("server", "host")
	srv.info, _ = srv.config.GetString("server", "info")
	port, _ := srv.config.GetInt("net", "port")
	go srv.listen(port)
	srv.dispatch()
}

func (srv *Server) dispatch() {
	xlog.Debug("Entering msg dispatcher")
	for {
		time.Sleep(1 * time.Millisecond)
		select {
		case msg := <-srv.Dispatch:
			srv.recvMsg(msg)
		case cl := <-srv.AddClient:
			name := cl.Name()
			if _, exists := srv.clients[name]; exists {
				xlog.Warning("Client registration failed: '%s'", name)
				go func() { cl.Register() <- false }()
				continue
			}
			go func() { cl.Register() <- true }()
			srv.clients[name] = cl
			xlog.Info("Client registered: '%s'", name)
			xlog.Info("Server has %d client(s)", len(srv.clients))
			xlog.Debug("Goroutines running: %d", runtime.NumGoroutine())
			srv.clientLogon(cl)
			srv.clientMotd(cl)
		case cl := <-srv.DelClient:
			name := cl.Name()
			delete(srv.clients, name)
			xlog.Info("Client deleted: '%s'", name)
			xlog.Info("Server has %d client(s)", len(srv.clients))
			xlog.Debug("Goroutines running: %d", runtime.NumGoroutine())
		default:
		}
	}
}

func (srv *Server) listen(port int) {
	if _, exists := srv.ports[port]; exists {
		xlog.Warning("Port %i already opened", port)
	}
	listen, err := net.Listen("tcp", ":"+strconv.Itoa(port))
	if err != nil {
		xlog.Fatal("Cannot listen on port %i (%s), exiting",
			port, err.Error())
		os.Exit(-1)
	}

	xlog.Info("Start listening on port %d", port)

	for {
		time.Sleep(1e6)
		conn, err := listen.Accept()
		if err != nil {
			xlog.Error(err.Error())
		} else {
			NewClient(srv, conn)
		}
	}
}

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

func (srv *Server) recvMsg(msg *irc.Message) {
	if msg.Args[0] != "" {
		srv.sendMsg(msg)
		return
	}
	cmd := msg.Cmd
	hook, exists := srvCommandHooks[cmd]
	if !exists {
		srv.sendCommand(msg.Pre, ERR_UNKNOWNCOMMAND, cmd, "Unknown command")
		return
	}
	argc := len(msg.Args)
	if argc < hook.MinArgs {
		srv.sendCommand(msg.Pre, ERR_NEEDMOREPARAMS, cmd,
			"Not enough parameters")
		return
	}
	hook.HookFn(srv, msg)
}

func (srv *Server) sendMsg(msg *irc.Message) {
	if strings.HasPrefix(msg.Args[0], "#") {
		srv.sendMsgToChannel(msg)
	} else {
		srv.sendMsgToClient(msg)
	}
}

func (srv *Server) sendMsgToChannel(msg *irc.Message) {
	subj := msg.Args[0]
	if _, exists := srv.subscriptions[subj]; !exists {
		return
	}
	subs := srv.subscriptions[subj]
	for _, sub := range subs {
		if _, exists := srv.clients[sub]; !exists {
			continue
		}
		cl := srv.clients[sub]
		cl.Receive(msg)
	}
}

func (srv *Server) sendMsgToClient(msg *irc.Message) {
	if _, exists := srv.clients[msg.Args[0]]; !exists {
		xlog.Error("Client '%s' does not exist", msg.Args[0])
		return
	}
	cl := srv.clients[msg.Args[0]]
	cl.Receive(msg)
}

func (srv *Server) sendCommand(dst, cmd, args, trail string) {
	srv.sendMsg(irc.M(srv.Host, cmd, args, trail))
}

func (srv *Server) sendClient(cl *Client, cmd, args, trail string) {
	srv.sendMsg(irc.M(srv.Host, cmd, cl.Name()+" "+args, trail))
}

func (srv *Server) clientLogon(cl *Client) {
	srv.sendClient(cl, RPL_WELCOME, "", "Willkommen!")
	srv.sendClient(cl, RPL_YOURHOST, "",
		fmt.Sprintf("Your host is %s, running on %s/%s",
			srv.Host, srv.software, srv.version))
	srv.sendClient(cl, RPL_CREATED, "", fmt.Sprintf("Created: %s", srv.created))
	srv.sendClient(cl, RPL_MYINFO,
		fmt.Sprintf(myinfo, srv.Host, srv.software, srv.version), "")
	srv.sendClient(cl, RPL_ISUPPORT, isupport, "are supported by this server")
}

func (srv *Server) clientMotd(cl *Client) {
	srv.sendClient(cl, RPL_MOTDSTART, "",
		fmt.Sprintf("- %s Message of the day -", srv.Host))
	for _, line := range strings.Split(srv.motd, "\n") {
		srv.sendClient(cl, RPL_MOTD, "", fmt.Sprintf("- %s", line))
	}
	srv.sendClient(cl, RPL_ENDOFMOTD, "", "End of MOTD command")
}

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

var srvCommandHooks = map[string]SrvCommandHook{
	"OPER":     {srvHandleCmdOper, 1, false, false},
	"QUIT":     {srvHandleCmdQuit, 0, false, false},
	"MODE":     {srvHandleCmdMode, 1, false, false},
	"LIST":     {srvHandleCmdList, 0, false, false},
	"VERSION":  {srvHandleCmdVersion, 0, false, false},
	"STATS":    {srvHandleCmdStats, 0, false, false},
	"TIME":     {srvHandleCmdTime, 0, false, false},
	"ADMIN":    {srvHandleCmdAdmin, 0, false, false},
	"INFO":     {srvHandleCmdInfo, 0, false, false},
	"WHO":      {srvHandleCmdWho, 0, false, false},
	"WHOIS":    {srvHandleCmdWhois, 0, false, false},
	"WHOWAS":   {srvHandleCmdWhowas, 0, false, false},
	"KILL":     {srvHandleCmdKill, 0, false, false},
	"PING":     {srvHandleCmdPing, 0, false, false},
	"PONG":     {srvHandleCmdPong, 0, false, false},
	"ERROR":    {srvHandleCmdError, 0, false, false},
	"AWAY":     {srvHandleCmdAway, 0, false, false},
	"REHASH":   {srvHandleCmdRehash, 0, false, false},
	"RESTART":  {srvHandleCmdRestart, 0, false, false},
	"SUMMON":   {srvHandleCmdSummon, 0, false, false},
	"USERS":    {srvHandleCmdUsers, 0, false, false},
	"USERHOST": {srvHandleCmdUserhost, 0, false, false},
	"ISON":     {srvHandleCmdIson, 0, false, false},
}

func srvHandleCmdOper(srv *Server, msg *irc.Message) {
}

func srvHandleCmdQuit(srv *Server, msg *irc.Message) {
}

func srvHandleCmdMode(srv *Server, msg *irc.Message) {
}

func srvHandleCmdList(srv *Server, msg *irc.Message) {
}

func srvHandleCmdVersion(srv *Server, msg *irc.Message) {
}

func srvHandleCmdStats(srv *Server, msg *irc.Message) {
}

func srvHandleCmdTime(srv *Server, msg *irc.Message) {
}

func srvHandleCmdAdmin(srv *Server, msg *irc.Message) {
}

func srvHandleCmdInfo(srv *Server, msg *irc.Message) {
}

func srvHandleCmdWho(srv *Server, msg *irc.Message) {
}

func srvHandleCmdWhois(srv *Server, msg *irc.Message) {
}

func srvHandleCmdWhowas(srv *Server, msg *irc.Message) {
}

func srvHandleCmdKill(srv *Server, msg *irc.Message) {
}

func srvHandleCmdPing(srv *Server, msg *irc.Message) {
	srv.sendCommand(msg.Pre, "PONG", "", msg.Args[0])
}

func srvHandleCmdPong(srv *Server, msg *irc.Message) {
}

func srvHandleCmdError(srv *Server, msg *irc.Message) {
}

func srvHandleCmdAway(srv *Server, msg *irc.Message) {
}

func srvHandleCmdRehash(srv *Server, msg *irc.Message) {
	srv.loadConfig()
	srv.sendCommand(msg.Pre, RPL_REHASHING, "", "Rehashing.")
	xlog.Info("Rehashing.")
}

func srvHandleCmdRestart(srv *Server, msg *irc.Message) {
}

func srvHandleCmdSummon(srv *Server, msg *irc.Message) {
}

func srvHandleCmdUsers(srv *Server, msg *irc.Message) {
}

func srvHandleCmdUserhost(srv *Server, msg *irc.Message) {
}

func srvHandleCmdIson(srv *Server, msg *irc.Message) {
}