From 898beb369a8be32686dcf656ec4f842b1cd432aa Mon Sep 17 00:00:00 2001
From: Joe Turki <git@joeturki.com>
Date: Sat, 20 Dec 2025 09:17:57 +0200
Subject: [PATCH] Add ice renomination option

---
 jsep.go      | 26 +++++++++++++++++-
 jsep_test.go | 78 ++++++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 91 insertions(+), 13 deletions(-)

diff --git a/jsep.go b/jsep.go
index ce0ba53..a0960f3 100644
--- a/jsep.go
+++ b/jsep.go
@@ -117,10 +117,34 @@ func (s *SessionDescription) WithValueAttribute(key, value string) *SessionDescr
 	return s
 }
 
+// addOrUpdateICEOption adds or updates the ice-options attribute with the given value.
+func (s *SessionDescription) addOrUpdateICEOption(value string) *SessionDescription {
+	for i := range s.Attributes {
+		if s.Attributes[i].Key == AttrKeyICEOptions {
+			prefix := " "
+			if s.Attributes[i].Value == "" {
+				prefix = ""
+			}
+
+			s.Attributes[i].Value += prefix + value
+
+			return s
+		}
+	}
+
+	return s.WithValueAttribute(AttrKeyICEOptions, value)
+}
+
 // WithICETrickleAdvertised advertises ICE trickle support in the session description.
 // See https://datatracker.ietf.org/doc/html/rfc9429#section-5.2.1
 func (s *SessionDescription) WithICETrickleAdvertised() *SessionDescription {
-	return s.WithValueAttribute(AttrKeyICEOptions, "trickle")
+	return s.addOrUpdateICEOption("trickle")
+}
+
+// WithICERenomination advertises ICE renomination support in the session description.
+// See https://datatracker.ietf.org/doc/html/draft-thatcher-ice-renomination-01#section-3
+func (s *SessionDescription) WithICERenomination() *SessionDescription {
+	return s.addOrUpdateICEOption("renomination")
 }
 
 // WithFingerprint adds a fingerprint to the session description.
diff --git a/jsep_test.go b/jsep_test.go
index 2478301..e21a7a8 100644
--- a/jsep_test.go
+++ b/jsep_test.go
@@ -37,34 +37,88 @@ func TestNewJSEPSessionDescription(t *testing.T) {
 }
 
 func TestSessionDescriptionAttributes(t *testing.T) {
-	sd, err := NewJSEPSessionDescription(false)
-	assert.NoError(t, err)
-
 	t.Run("WithPropertyAttribute", func(t *testing.T) {
+		sd, err := NewJSEPSessionDescription(false)
+		assert.NoError(t, err)
 		sd = sd.WithPropertyAttribute(AttrKeyRTCPMux)
 		assert.Len(t, sd.Attributes, 1)
 		assert.Equal(t, AttrKeyRTCPMux, sd.Attributes[0].Key)
 	})
 
 	t.Run("WithValueAttribute", func(t *testing.T) {
+		sd, err := NewJSEPSessionDescription(false)
+		assert.NoError(t, err)
 		sd = sd.WithValueAttribute(AttrKeyMID, "video")
-		assert.Len(t, sd.Attributes, 2)
-		assert.Equal(t, AttrKeyMID, sd.Attributes[1].Key)
-		assert.Equal(t, "video", sd.Attributes[1].Value)
+		assert.Len(t, sd.Attributes, 1)
+		assert.Equal(t, AttrKeyMID, sd.Attributes[0].Key)
+		assert.Equal(t, "video", sd.Attributes[0].Value)
 	})
 
 	t.Run("WithICETrickleAdvertised", func(t *testing.T) {
+		sd, err := NewJSEPSessionDescription(false)
+		assert.NoError(t, err)
 		sd = sd.WithICETrickleAdvertised()
-		assert.Len(t, sd.Attributes, 3)
-		assert.Equal(t, AttrKeyICEOptions, sd.Attributes[2].Key)
-		assert.Equal(t, "trickle", sd.Attributes[2].Value)
+		assert.Len(t, sd.Attributes, 1)
+		assert.Equal(t, AttrKeyICEOptions, sd.Attributes[0].Key)
+		assert.Equal(t, "trickle", sd.Attributes[0].Value)
+	})
+
+	t.Run("WithICERenomination", func(t *testing.T) {
+		sd, err := NewJSEPSessionDescription(false)
+		assert.NoError(t, err)
+		sd = sd.WithICETrickleAdvertised().WithICERenomination()
+		assert.Len(t, sd.Attributes, 1)
+		assert.Equal(t, AttrKeyICEOptions, sd.Attributes[0].Key)
+		assert.Equal(t, "trickle renomination", sd.Attributes[0].Value)
 	})
 
 	t.Run("WithFingerprint", func(t *testing.T) {
+		sd, err := NewJSEPSessionDescription(false)
+		assert.NoError(t, err)
 		sd = sd.WithFingerprint("sha-256", "test-fingerprint")
-		assert.Len(t, sd.Attributes, 4)
-		assert.Equal(t, "fingerprint", sd.Attributes[3].Key)
-		assert.Equal(t, "sha-256 test-fingerprint", sd.Attributes[3].Value)
+		assert.Len(t, sd.Attributes, 1)
+		assert.Equal(t, "fingerprint", sd.Attributes[0].Key)
+		assert.Equal(t, "sha-256 test-fingerprint", sd.Attributes[0].Value)
+	})
+}
+
+func TestSessionDescription_ICEOptions_Combined(t *testing.T) {
+	t.Run("WithICETrickleAdvertised and WithICERenominationAdvertised", func(t *testing.T) {
+		sd, err := NewJSEPSessionDescription(false)
+		assert.NoError(t, err)
+
+		sd = sd.WithICETrickleAdvertised().WithICERenomination()
+
+		iceOptionsCount := 0
+		var iceOptionsValue string
+		for _, attr := range sd.Attributes {
+			if attr.Key == AttrKeyICEOptions {
+				iceOptionsCount++
+				iceOptionsValue = attr.Value
+			}
+		}
+
+		assert.Equal(t, 1, iceOptionsCount, "Should have exactly one ice-options attribute")
+		assert.Equal(t, "trickle renomination", iceOptionsValue, "Should combine both values with space")
+	})
+
+	t.Run("WithICERenominationAdvertised and WithICETrickleAdvertised (reverse order)", func(t *testing.T) {
+		sd, err := NewJSEPSessionDescription(false)
+		assert.NoError(t, err)
+
+		sd = sd.WithICERenomination().WithICETrickleAdvertised()
+
+		iceOptionsCount := 0
+		var iceOptionsValue string
+		for _, attr := range sd.Attributes {
+			if attr.Key == AttrKeyICEOptions {
+				iceOptionsCount++
+				iceOptionsValue = attr.Value
+			}
+		}
+
+		assert.Equal(t, 1, iceOptionsCount, "Should have exactly one ice-options attribute")
+		assert.Equal(t, "renomination trickle", iceOptionsValue, "Should combine both values with space")
 	})
 }