package main

import (
	"bytes"
	"fmt"
	"io"
	"libnmdc"
	"net"
	"strings"
	"time"
)

type Server struct {
	eventChan    chan Event
	running      bool
	name         string
	client       *Client
	channel      Channel // Single blessed channel
	upstreamAddr libnmdc.HubAddress
	upstream     libnmdc.HubConnection
	motd         string
}

func NewServer(name string, upstream libnmdc.HubAddress) *Server {
	return &Server{eventChan: make(chan Event),
		name:         name,
		client:       nil,
		motd:         "Connected to " + name,
		upstreamAddr: upstream,
		channel: Channel{
			clientMap: make(map[string]*Client),
			modeMap:   make(map[string]*ClientMode),
		},
	}
}

func (s *Server) RunClient(conn net.Conn) {

	s.client = &Client{
		connection: conn,
		connected:  true,
	}

	// Send the connection handshake
	s.client.reply(rplMOTDStart)
	motd := s.motd
	for len(motd) > 80 {
		s.client.reply(rplMOTD, motd[:80])
		motd = motd[80:]
	}
	if len(motd) > 0 {
		s.client.reply(rplMOTD, motd)
	}
	s.client.reply(rplEndOfMOTD)

	// Read loop
	for {
		s.client.connection.SetReadDeadline(time.Now().Add(time.Second * CLIENT_READ_TIMEOUT_SEC))
		buf := make([]byte, CLIENT_READ_BUFFSIZE)
		ln, err := s.client.connection.Read(buf)
		if err != nil {
			if err == io.EOF {
				s.client.disconnect()
				return // FIXME cleanup
			}
			continue
		}

		rawLines := buf[:ln]
		rawLines = bytes.Replace(rawLines, []byte("\r\n"), []byte("\n"), -1)
		rawLines = bytes.Replace(rawLines, []byte("\r"), []byte("\n"), -1)
		lines := bytes.Split(rawLines, []byte("\n"))
		for _, line := range lines {
			if len(line) > 0 {
				s.handleCommandEvent(string(line))
			}
		}
	}

}

func (s *Server) handleCommandEvent(input string) {

	//Client send a command
	fields := strings.Fields(input)
	if len(fields) < 1 {
		return
	}

	if strings.HasPrefix(fields[0], ":") {
		fields = fields[1:]
	}
	command := strings.ToUpper(fields[0])
	args := fields[1:]

	s.handleCommand(s.client, command, args)

}

func (s *Server) handleCommand(client *Client, command string, args []string) {

	switch command {
	case "PING":
		client.reply(rplPong)

	case "INFO":
		client.reply(rplInfo, APP_DESCRIPTION)

	case "VERSION":
		client.reply(rplVersion, VERSION)

	case "NICK":
		client.reply(rplKill, "Can't change nicks on this server", "")
		client.disconnect()

	case "USER":
		if client.registered == true {
			client.reply(rplKill, "You're already registered.", "")
			client.disconnect()
		}

		if client.nick == "" {
			client.reply(rplKill, "Your nickname is already being used", "")
			client.disconnect()

		} else {
			client.reply(rplWelcome)
			client.registered = true

			// Spawn
		}

	case "JOIN":
		if client.registered == false {
			client.reply(errNotReg)
			return
		}

		if len(args) < 1 {
			client.reply(errMoreArgs)
			return
		}

		switch args[0] {
		case BLESSED_CHANNEL:
			// That's fine, but they're already there
		case "0":
			// Intend to quit all channels, but we don't allow that
		default:
			client.reply(rplKill, "There is only '"+BLESSED_CHANNEL+"'.", "")
			client.disconnect()
		}

	case "PART":
		if client.registered == false {
			client.reply(errNotReg)
			return
		}

		// you can check out any time you like, but you can never leave
		// we'll need to transmit client.reply(rplPart, c.nick, channel.name, reason) messages on behalf of other nmdc users, though

	case "PRIVMSG":
		if client.registered == false {
			client.reply(errNotReg)
			return
		}

		if len(args) < 2 {
			client.reply(errMoreArgs)
			return
		}

		message := strings.Join(args[1:], " ")

		// IRC is case-insensitive case-preserving. We can respect that for the
		//  channel name, but not really for user nicks
		recipient := strings.ToLower(args[0])

		if recipient == BLESSED_CHANNEL {
			for _, c := range s.channel.clientMap {
				if c != client {
					c.reply(rplMsg, client.nick, args[0], message)
				}
			}

		} else if nmdcUser, clientExists := s.upstream.Users[args[0]]; clientExists {

			s.upstream.SayPrivate(recipient, message)
			// client2.reply(rplMsg, client.nick, client2.nick, message)

		} else {
			client.reply(errNoSuchNick, args[0])

		}

	case "QUIT":
		if client.registered == false {
			client.reply(errNotReg)
			return
		}

		client.disconnect()

	case "TOPIC":
		if client.registered == false {
			client.reply(errNotReg)
			return
		}

		if len(args) < 1 {
			client.reply(errMoreArgs)
			return
		}

		exists := strings.ToLower(args[0]) == BLESSED_CHANNEL
		if exists == false {
			client.reply(errNoSuchNick, args[0])
			return
		}

		// Valid topic get
		if len(args) == 1 {
			client.reply(rplTopic, BLESSED_CHANNEL, s.upstream.HubName)
			return
		}

		// Disallow topic set
		client.reply(errNoPriv)
		return

	case "LIST":
		if client.registered == false {
			client.reply(errNotReg)
			return
		}

		listItem := fmt.Sprintf("%s %d :%s", BLESSED_CHANNEL, len(s.channel.clientMap), s.upstream.HubName)
		client.reply(rplList, listItem)
		client.reply(rplListEnd)

	case "OPER":
		if client.registered == false {
			client.reply(errNotReg)
			return
		}

		if len(args) < 2 {
			client.reply(errMoreArgs)
			return
		}

		//username := args[0]
		//password := args[1]

		if false { // op the user
			client.operator = true
			client.reply(rplOper)
			return
		} else {
			client.reply(errPassword)

		}

	case "KILL":
		if client.registered == false {
			client.reply(errNotReg)
			return
		}

		client.reply(errNoPriv)
		return

	case "KICK":
		if client.registered == false {
			client.reply(errNotReg)
			return
		}

		client.reply(errNoPriv)
		return

	case "MODE":
		if client.registered == false {
			client.reply(errNotReg)
			return
		}

		if len(args) < 1 {
			client.reply(errMoreArgs)
			return
		}

		if strings.ToLower(args[0]) != BLESSED_CHANNEL {
			client.reply(errNoSuchNick, args[0])
			return
		}

		if len(args) == 1 {
			//No more args, they just want the mode
			client.reply(rplChannelModeIs, args[0], BLESSED_CHANNEL_MODE, "")
		} else {
			// Setting modes is disallowed
			client.reply(errNoPriv)
		}

		return

	default:
		client.reply(errUnknownCommand, command)
	}
}