From e1d00ae799013d174fc3504fc7493436a3fdb263 Mon Sep 17 00:00:00 2001
From: Russ Garrett <russ@garrett.co.uk>
Date: Wed, 25 Jan 2017 15:39:59 +0000
Subject: [PATCH] Add support for parsing IRCv3 tags in received messages

---
 irc.go            | 31 +++++++++++++++++++++++++++++++
 irc_parse_test.go | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 irc_struct.go     |  1 +
 3 files changed, 79 insertions(+)
 create mode 100644 irc_parse_test.go

diff --git a/irc.go b/irc.go
index eb9174d..af50c74 100644
--- a/irc.go
+++ b/irc.go
@@ -87,6 +87,17 @@ func (irc *Connection) readLoop() {
 	}
 }
 
+// Unescape tag values as defined in the IRCv3.2 message tags spec
+// http://ircv3.net/specs/core/message-tags-3.2.html
+func unescapeTagValue(value string) string {
+	value = strings.Replace(value, "\\:", ";", -1)
+	value = strings.Replace(value, "\\s", " ", -1)
+	value = strings.Replace(value, "\\\\", "\\", -1)
+	value = strings.Replace(value, "\\r", "\r", -1)
+	value = strings.Replace(value, "\\n", "\n", -1)
+	return value
+}
+
 //Parse raw irc messages
 func parseToEvent(msg string) (*Event, error) {
 	msg = strings.TrimSuffix(msg, "\n") //Remove \r\n
@@ -95,6 +106,26 @@ func parseToEvent(msg string) (*Event, error) {
 	if len(msg) < 5 {
 		return nil, errors.New("Malformed msg from server")
 	}
+
+	if msg[0] == '@' {
+		// IRCv3 Message Tags
+		if i := strings.Index(msg, " "); i > -1 {
+			event.Tags = make(map[string]string)
+			tags := strings.Split(msg[1:i], ";")
+			for _, data := range tags {
+				parts := strings.SplitN(data, "=", 2)
+				if len(parts) == 1 {
+					event.Tags[parts[0]] = ""
+				} else {
+					event.Tags[parts[0]] = unescapeTagValue(parts[1])
+				}
+			}
+			msg = msg[i+1 : len(msg)]
+		} else {
+			return nil, errors.New("Malformed msg from server")
+		}
+	}
+
 	if msg[0] == ':' {
 		if i := strings.Index(msg, " "); i > -1 {
 			event.Source = msg[1:i]
diff --git a/irc_parse_test.go b/irc_parse_test.go
new file mode 100644
index 0000000..447a590
--- /dev/null
+++ b/irc_parse_test.go
@@ -0,0 +1,47 @@
+package irc
+
+import (
+	"fmt"
+	"testing"
+)
+
+func checkResult(t *testing.T, event *Event) {
+	if event.Nick != "nick" {
+		t.Fatal("Parse failed: nick")
+	}
+	if event.User != "~user" {
+		t.Fatal("Parse failed: user")
+	}
+	if event.Code != "PRIVMSG" {
+		t.Fatal("Parse failed: code")
+	}
+	if event.Arguments[0] != "#channel" {
+		t.Fatal("Parse failed: channel")
+	}
+	if event.Arguments[1] != "message text" {
+		t.Fatal("Parse failed: message")
+	}
+}
+
+func TestParse(t *testing.T) {
+	event, err := parseToEvent(":nick!~user@host PRIVMSG #channel :message text")
+	if err != nil {
+		t.Fatal("Parse PRIVMSG failed")
+	}
+	checkResult(t, event)
+}
+
+func TestParseTags(t *testing.T) {
+	event, err := parseToEvent("@tag;+tag2=raw+:=,escaped\\:\\s\\\\ :nick!~user@host PRIVMSG #channel :message text")
+	if err != nil {
+		t.Fatal("Parse PRIVMSG with tags failed")
+	}
+	checkResult(t, event)
+	fmt.Printf("%s", event.Tags)
+	if _, ok := event.Tags["tag"]; !ok {
+		t.Fatal("Parsing value-less tag failed")
+	}
+	if event.Tags["+tag2"] != "raw+:=,escaped; \\" {
+		t.Fatal("Parsing tag failed")
+	}
+}
diff --git a/irc_struct.go b/irc_struct.go
index a188d9d..e509dbb 100644
--- a/irc_struct.go
+++ b/irc_struct.go
@@ -59,6 +59,7 @@ type Event struct {
 	Source     string //<host>
 	User       string //<usr>
 	Arguments  []string
+	Tags       map[string]string
 	Connection *Connection
 }