1 files changed, 116 insertions, 0 deletions
diff --git a/xmpp/gateway/gateway.go b/xmpp/gateway/gateway.go
index 534ee7e..9cd2102 100644
--- a/xmpp/gateway/gateway.go
+++ b/xmpp/gateway/gateway.go
@@ -1,8 +1,13 @@
 package gateway
 
 import (
+	"bytes"
+	"encoding/base64"
 	"encoding/xml"
 	"github.com/pkg/errors"
+	"fmt"
+	"io"
+	"sort"
 	"strings"
 	"sync"
 
@@ -37,6 +42,19 @@ var DirtySessions = false
 // MessageOutgoingPermission allows to fake outgoing messages by foreign JIDs
 var MessageOutgoingPermission = false
 
+// CapsType is a capability category
+type CapsType int
+const (
+	CapsAudio CapsType = iota
+)
+
+// ContactType is a disco JID category
+type ContactType int
+const (
+	ContactTransport CapsType = iota
+	ContactPM
+)
+
 // SendMessage creates and sends a message stanza
 func SendMessage(to string, from string, body string, id string, component *xmpp.Component, reply *Reply, isOutgoing bool) {
 	sendMessageWrapper(to, from, body, id, component, reply, "", isOutgoing)
@@ -225,6 +243,9 @@ var SPResource = args.NewString()
 // SPImmed skips queueing
 var SPImmed = args.NewBool(args.Default(true))
 
+// SPCaps is a XEP-0115 verification string
+var SPCaps = args.NewString()
+
 func newPresence(bareJid string, to string, args ...args.V) stanza.Presence {
 	var presenceFrom string
 	if SPFrom.IsSet(args) {
@@ -280,6 +301,16 @@ func newPresence(bareJid string, to string, args ...args.V) stanza.Presence {
 			})
 		}
 	}
+	if SPCaps.IsSet(args) {
+		ver := SPCaps.Get(args)
+		if ver != "" {
+			presence.Extensions = append(presence.Extensions, extensions.CapsExtension{
+				Hash: "sha-1",
+				Node: "https://dev.narayana.im/narayana/telegabber/",
+				Ver:  ver,
+			})
+		}
+	}
 
 	return presence
 }
@@ -356,3 +387,88 @@ func SplitJID(from string) (string, string, bool) {
 	}
 	return fromJid.Bare(), fromJid.Resource, true
 }
+
+func getDiscoFeatures(caps []CapsType) []string {
+	features := []string{
+		"http://jabber.org/protocol/caps",
+		"http://jabber.org/protocol/disco#info",
+	}
+	for typ := range features {
+		switch typ {
+		case CapsAudio:
+			features = append(
+				features,
+				"urn:xmpp:jingle-message:0",
+				"urn:xmpp:jingle:1",
+				"urn:xmpp:jingle:apps:dtls:0",
+				"urn:xmpp:jingle:apps:rtp:1",
+				"urn:xmpp:jingle:apps:rtp:audio",
+				"urn:xmpp:jingle:transports:ice-udp:1",
+			)
+		}
+	}
+	return features
+}
+
+// GetDiscoInfo generates a disco info IQ query response
+func GetDiscoInfo(typ ContactType, features []string) *stanza.DiscoInfo {
+	disco := stanza.DiscoInfo{}
+	if typ == ContactPM {
+		disco.AddIdentity("", "account", "registered")
+	} else {
+		disco.AddIdentity("Telegram Gateway", "gateway", "telegram")
+	}
+	disco.AddFeatures(features...)
+	return &disco
+}
+
+
+// GetCapsVer hashes a capabilities set into a verification string
+func GetCapsVer(caps []CapsType) (string, error) {
+	features := getDiscoFeatures(caps)
+	disco := GetDiscoInfo(features)
+	discoToCapsHash(disco)
+	buf := new(bytes.Buffer)
+	binval := base64.NewEncoder(base64.StdEncoding, buf)
+	_, err = io.Copy(binval, file)
+	binval.Close()
+	if err != nil {
+		return "", errors.Wrap(err, "Error calculating caps base64")
+	}
+	return buf.String(), nil
+}
+
+func iOctetComparator(a, b string) bool {
+	return a < b
+}
+
+func discoToCaps(disco *stanza.DiscoInfo) string {
+	var s strings.Builder
+	var identities, vars, capsForms []string
+
+	for _, identity := range disco.Identity {
+		identities = append(identities, fmt.Sprintf(
+			"%s/%s//%s",
+			identity.Category,
+			identity.Type,
+			identity.Name,
+		))
+	}
+	sort.Slice(identities, iOctetComparator)
+	for _, identity := range identities {
+		s.WriteString(identity)
+		s.WriteString(">")
+	}
+
+	for _, feature := range disco.Features {
+		vars = append(vars, feature.Var)
+	}
+	sort.Slice(vars, iOctetComparator)
+	for _, var := range vars {
+		s.WriteString(var)
+		s.WriteString(">")
+	}
+
+	for disco
+	s.WriteString(
+}