package irc

import (
	"strings"

	"github.com/gissleh/irc/list"
)

// A Channel is a target that manages the userlist
type Channel struct {
	id       string
	name     string
	userlist *list.List
	parted   bool
}

// ID returns a unique ID for the channel target.
func (channel *Channel) ID() string {
	return channel.id
}

// Kind returns "channel"
func (channel *Channel) Kind() string {
	return "channel"
}

// Name gets the channel name
func (channel *Channel) Name() string {
	return channel.name
}

func (channel *Channel) State() ClientStateTarget {
	return ClientStateTarget{
		Kind:  "channel",
		Name:  channel.name,
		Users: channel.userlist.Users(),
	}
}

// UserList gets the channel userlist
func (channel *Channel) UserList() list.Immutable {
	return channel.userlist.Immutable()
}

// Parted returnes whether the channel has been parted
func (channel *Channel) Parted() bool {
	return channel.parted
}

// AddHandler handles messages routed to this channel by the client's event loop
func (channel *Channel) Handle(event *Event, client *Client) {
	switch event.Name() {
	case "packet.join":
		{
			// Support extended-join
			account := ""
			if accountArg := event.Arg(1); accountArg != "" && accountArg != "*" {
				account = accountArg
			}

			channel.userlist.Insert(list.User{
				Nick:    event.Nick,
				User:    event.User,
				Host:    event.Host,
				Account: account,
			})
		}
	case "packet.part", "packet.quit":
		{
			channel.userlist.Remove(event.Nick)
		}
	case "packet.kick":
		{
			channel.userlist.Remove(event.Arg(1))
		}
	case "packet.nick":
		{
			channel.userlist.Rename(event.Nick, event.Arg(0))
		}
	case "packet.account":
		{
			newAccount := event.Arg(0)

			if newAccount != "*" && newAccount != "" {
				channel.userlist.Patch(event.Nick, list.UserPatch{Account: newAccount})
			} else {
				channel.userlist.Patch(event.Nick, list.UserPatch{ClearAccount: true})
			}
		}
	case "packet.away":
		{
			if event.Text != "" {
				channel.userlist.Patch(event.Nick, list.UserPatch{Away: event.Text})
			} else {
				channel.userlist.Patch(event.Nick, list.UserPatch{ClearAway: true})
			}
		}
	case "packet.chghost":
		{
			newUser := event.Arg(0)
			newHost := event.Arg(1)

			channel.userlist.Patch(event.Nick, list.UserPatch{User: newUser, Host: newHost})
		}
	case "packet.353": // NAMES
		{
			channel.userlist.SetAutoSort(false)
			tokens := strings.Split(event.Text, " ")
			for _, token := range tokens {
				channel.userlist.InsertFromNamesToken(token)
			}
		}
	case "packet.366": // End of NAMES
		{
			channel.userlist.SetAutoSort(true)
		}
	case "packet.mode":
		{
			isupport := client.ISupport()
			plus := false
			argIndex := 2

			for _, ch := range event.Arg(1) {
				if ch == '+' {
					plus = true
					continue
				}
				if ch == '-' {
					plus = false
					continue
				}

				arg := ""
				if isupport.ModeTakesArgument(ch, plus) {
					arg = event.Arg(argIndex)
					argIndex++
				}

				if isupport.IsPermissionMode(ch) {
					if plus {
						channel.userlist.AddMode(arg, ch)
					} else {
						channel.userlist.RemoveMode(arg, ch)
					}
				} else {
					// TODO: track non-permission modes
				}
			}
		}
	case "packet.privmsg", "ctcp.action":
		{
			if accountTag, ok := event.Tags["account"]; ok && accountTag != "" {
				channel.userlist.Patch(event.Nick, list.UserPatch{Account: accountTag})
			}
		}
	}
}