From 03c79fc5f1af69fe2f3d5caa409dca0a820d94f7 Mon Sep 17 00:00:00 2001
From: David Florness <david@florness.com>
Date: Sun, 17 Jul 2022 18:19:11 -0400
Subject: [PATCH] Don't send the same MSC more than once in the same message

---
 main.go     | 7 +++++++
 msc_test.go | 9 +++++++++
 2 files changed, 16 insertions(+)

diff --git a/main.go b/main.go
index 480840c..852602c 100644
--- a/main.go
+++ b/main.go
@@ -158,9 +158,16 @@ func getMsgResponse(client *mautrix.Client, evt *event.Event) *event.MessageEven
 func getMSCs(body string) (mscs []uint) {
 	bodyNoReplies := event.TrimReplyFallbackText(body)
 	matches := MSC_REGEX.FindAllStringSubmatch(bodyNoReplies, -1)
+	mscSet := make(map[int]struct{})
 	for _, match := range matches {
 		// error can never happen because of %d in regex
 		msc, _ := strconv.Atoi(match[1])
+		_, exists := mscSet[msc]
+		if exists {
+			// don't add the same MSC twice
+			continue
+		}
+		mscSet[msc] = struct{}{}
 		mscs = append(mscs, uint(msc))
 	}
 	return mscs
diff --git a/msc_test.go b/msc_test.go
index 68afee8..76588f4 100644
--- a/msc_test.go
+++ b/msc_test.go
@@ -23,3 +23,12 @@ func TestCapitalization(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestNoRepeats(t *testing.T) {
+	mscs := getMSCs("That msc seems to be the last prerequisite for MSC2677: https://github.com/uhoreg/matrix-doc/blob/aggregations-reactions/proposals/2677-reactions.md#msc2677-annotations-and-reactions")
+	if len(mscs) != 1 {
+		t.Fail()
+	} else if mscs[0] != 2677 {
+		t.Fail()
+	}
+}
-- 
2.38.4