package ftp

import (
	"strings"

	osm "git.loafle.net/overflow/service_matcher-go"
)

// FTP Status codes, defined in RFC 959
const (
	statusReadyServer         = "120"
	statusOK                  = "200"
	statusNewConnectOK        = "220"
	statusSystemNameOK        = "215"
	statusCloseConnect        = "221"
	statusUnkownCMD           = "202"
	statusTlsUseOK            = "234"
	statusCloseControlConnect = "421"
	statusSyntaxErr           = "500"
	statusParamSyntaxErr      = "501"
	statusNotUseCMD           = "502"
	statusIncorrectCMD        = "503"
	statusNotLoggedIn         = "530"
	statusTlsNotUse           = "534"
	statusNeedUserId          = "332"
)

type FTPMatcher struct {
	osm.Matchers
	meta osm.Metadata
}

func (ftp *FTPMatcher) Key() string {
	return "FTP"
}

func (ftp *FTPMatcher) Name() string {
	return "FTP"
}

func (ftp *FTPMatcher) Meta() osm.Metadata {
	return ftp.meta
}

func (ftp *FTPMatcher) IsPrePacket() bool {
	return true
}

func (ftp *FTPMatcher) HasResponse(index int) bool {
	return true
}

func (ftp *FTPMatcher) IsError(info osm.MatchInfo, index int, packet *osm.Packet) bool {
	return false
}

func (ftp *FTPMatcher) Match(info osm.MatchInfo, index int, packet *osm.Packet) error {

	if packet == nil || packet.Buffer == nil || packet.Len == 0 {
		return osm.NoPacketReceivedError()
	}

	str := strings.Split(string(packet.Buffer), "\r\n")[0]
	if len(str) < 4 {
		return osm.NotMatchedError()
	}
	code := str[:3]

	if index == 0 {
		switch code {
		case statusNewConnectOK, statusReadyServer:
			ftp.meta["comment"] = str[4:]
			return nil
		}
	} else if index == 1 {
		switch code {
		case statusCloseConnect, statusSyntaxErr:
			return nil
		}
	}

	return osm.NotMatchedError()
}

func NewMatcher() osm.Matcher {

	m := &FTPMatcher{}
	m.meta = osm.NewMetadata()

	quitStr := "QUIT\r\n"
	quitByte := make([]byte, len(quitStr))
	copy(quitByte[:], quitStr)
	m.AddPacket(osm.NewPacket(quitByte, len(quitStr)))

	return m
}