package http

import (
	"strings"

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

type HTTPMatcher struct {
	osm.Matchers
}

func (m *HTTPMatcher) Key() string {
	return "HTTP"
}

func (m *HTTPMatcher) Type() string {
	return "WEB"
}

func (m *HTTPMatcher) Vendor(matchCtx *osm.MatchCtx) string {
	return "UNKNOWN"
}

func (m *HTTPMatcher) Version(matchCtx *osm.MatchCtx) string {
	return "UNKNOWN"
}

func (m *HTTPMatcher) OsType(matchCtx *osm.MatchCtx) string {
	return "UNKNOWN"
}

func (m *HTTPMatcher) OsVersion(matchCtx *osm.MatchCtx) string {
	return "UNKNOWN"
}

func (m *HTTPMatcher) Name(matchCtx *osm.MatchCtx) string {
	name := "HTTP"
	if v, ok := matchCtx.GetAttribute("server"); ok {
		name = name + " (" + v + ")"
	}
	return name
}

func (m *HTTPMatcher) IsPrePacket() bool {
	return false
}

func (m *HTTPMatcher) HasResponse(matchCtx *osm.MatchCtx, index int) bool {
	return true
}

func (m *HTTPMatcher) IsError(matchCtx *osm.MatchCtx, index int, packet *osm.Packet) bool {
	return false
}

func (m *HTTPMatcher) Match(matchCtx *osm.MatchCtx, index int, packet *osm.Packet) error {

	if packet == nil || !packet.Valid() {
		return osm.NoPacketReceivedError()
	}

	str := string(packet.Bytes())
	elems := strings.Split(str, "\r\n")

	if len(elems) <= 0 || 9 > len(elems[0]) {
		return osm.NotMatchedError()
	}

	protocol := (elems[0])[:8]

	if !strings.HasPrefix(protocol, "HTTP/") {
		return osm.NotMatchedError()
	}

	serverName := ""
	for _, valueStr := range elems {
		tempElems := strings.Split(valueStr, ":")

		if 0 == strings.Compare(tempElems[0], "Server") {
			serverName = strings.TrimSpace(tempElems[1])
			break
		}
	}

	matchCtx.SetAttribute("protocol_version", protocol)
	if len(serverName) > 0 {
		matchCtx.SetAttribute("server", serverName)
	}

	return nil
}

func NewMatcher() osm.Matcher {

	m := &HTTPMatcher{}

	reqStr := "GET / HTTP/1.1\r\n\r\n"
	byte := make([]byte, len(reqStr))
	copy(byte[:], reqStr)

	m.AddPacket(osm.NewPacket(byte, len(reqStr)))

	return m
}