From fe1cee0159f0228ecaf64a0a7bcc0fd137de017a Mon Sep 17 00:00:00 2001
From: beerpsi <92439990+beer-psi@users.noreply.github.com>
Date: Fri, 7 Nov 2025 02:24:07 +0700
Subject: [PATCH] fix(share): slice content label by utf-8 runes (#4634)

* fix(share): slice content label by utf-8 runes

* Apply suggestions about avoiding allocations

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* lint: remove unused import

* test: add test cases for CJK truncation

* test: add tests for ASCII labels too

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 core/share.go      | 17 +++++++++++++++--
 core/share_test.go | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/core/share.go b/core/share.go
index 202c27d8..d653795e 100644
--- a/core/share.go
+++ b/core/share.go
@@ -119,8 +119,21 @@ func (r *shareRepositoryWrapper) Save(entity interface{}) (string, error) {
 		log.Error(r.ctx, "Invalid Resource ID", "id", firstId)
 		return "", model.ErrNotFound
 	}
-	if len(s.Contents) > 30 {
-		s.Contents = s.Contents[:26] + "..."
+
+	const maxContentRunes = 30
+	const truncateToRunes = 26
+
+	var runeCount int
+	var truncateIndex int
+	for i := range s.Contents {
+		runeCount++
+		if runeCount == truncateToRunes+1 {
+			truncateIndex = i
+		}
+	}
+
+	if runeCount > maxContentRunes {
+		s.Contents = s.Contents[:truncateIndex] + "..."
 	}
 
 	id, err = r.Persistable.Save(s)
diff --git a/core/share_test.go b/core/share_test.go
index 21069bb5..ad5a986b 100644
--- a/core/share_test.go
+++ b/core/share_test.go
@@ -38,6 +38,38 @@ var _ = Describe("Share", func() {
 				Expect(id).ToNot(BeEmpty())
 				Expect(entity.ID).To(Equal(id))
 			})
+
+			It("does not truncate ASCII labels shorter than 30 characters", func() {
+				_ = ds.MediaFile(ctx).Put(&model.MediaFile{ID: "456", Title: "Example Media File"})
+				entity := &model.Share{Description: "test", ResourceIDs: "456"}
+				_, err := repo.Save(entity)
+				Expect(err).ToNot(HaveOccurred())
+				Expect(entity.Contents).To(Equal("Example Media File"))
+			})
+
+			It("truncates ASCII labels longer than 30 characters", func() {
+				_ = ds.MediaFile(ctx).Put(&model.MediaFile{ID: "789", Title: "Example Media File But The Title Is Really Long For Testing Purposes"})
+				entity := &model.Share{Description: "test", ResourceIDs: "789"}
+				_, err := repo.Save(entity)
+				Expect(err).ToNot(HaveOccurred())
+				Expect(entity.Contents).To(Equal("Example Media File But The..."))
+			})
+
+			It("does not truncate CJK labels shorter than 30 runes", func() {
+				_ = ds.MediaFile(ctx).Put(&model.MediaFile{ID: "456", Title: "青春コンプレックス"})
+				entity := &model.Share{Description: "test", ResourceIDs: "456"}
+				_, err := repo.Save(entity)
+				Expect(err).ToNot(HaveOccurred())
+				Expect(entity.Contents).To(Equal("青春コンプレックス"))
+			})
+
+			It("truncates CJK labels longer than 30 runes", func() {
+				_ = ds.MediaFile(ctx).Put(&model.MediaFile{ID: "789", Title: "私の中の幻想的世界観及びその顕現を想起させたある現実での出来事に関する一考察"})
+				entity := &model.Share{Description: "test", ResourceIDs: "789"}
+				_, err := repo.Save(entity)
+				Expect(err).ToNot(HaveOccurred())
+				Expect(entity.Contents).To(Equal("私の中の幻想的世界観及びその顕現を想起させたある現実..."))
+			})
 		})
 
 		Describe("Update", func() {