tui: make entry input backspace rune-safe

2 files changed, 38 insertions, 6 deletions

diff --git a/internal/tui/entries.go b/internal/tui/entries.go
index 512e9d2..ca84300 100644
--- a/internal/tui/entries.go
+++ b/internal/tui/entries.go
@@ -7,6 +7,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode/utf8"
 
 	"codeberg.org/snonux/timr/internal/duration"
 	"codeberg.org/snonux/timr/internal/worktime"
@@ -150,9 +151,7 @@ func (m *EntriesModel) updateEditMode(keyMsg tea.KeyMsg) bool {
 		m.editMode = false
 		m.input = ""
 	case "backspace":
-		if len(m.input) > 0 {
-			m.input = m.input[:len(m.input)-1]
-		}
+		m.input = trimLastRune(m.input)
 	default:
 		if keyMsg.Type == tea.KeyRunes {
 			m.input += string(keyMsg.Runes)
@@ -183,9 +182,7 @@ func (m *EntriesModel) updateSearchFilterMode(keyMsg tea.KeyMsg) bool {
 		m.filterMode = false
 		m.input = ""
 	case "backspace":
-		if len(m.input) > 0 {
-			m.input = m.input[:len(m.input)-1]
-		}
+		m.input = trimLastRune(m.input)
 	default:
 		if keyMsg.Type == tea.KeyRunes {
 			m.input += string(keyMsg.Runes)
@@ -695,3 +692,16 @@ func insertEntryAt(entries []worktime.Entry, idx int, entry worktime.Entry) []wo
 	entries[idx] = entry
 	return entries
 }
+
+func trimLastRune(value string) string {
+	if value == "" {
+		return ""
+	}
+
+	_, size := utf8.DecodeLastRuneInString(value)
+	if size <= 0 {
+		return ""
+	}
+
+	return value[:len(value)-size]
+}
diff --git a/internal/tui/entries_test.go b/internal/tui/entries_test.go
index 9377f30..da5a5c4 100644
--- a/internal/tui/entries_test.go
+++ b/internal/tui/entries_test.go
@@ -141,6 +141,28 @@ func TestEntriesValueEditFlow(t *testing.T) {
 	}
 }
 
+func TestEntriesBackspaceIsRuneSafeInEditMode(t *testing.T) {
+	model := NewEntriesModel(sampleEntries(1))
+	model.editMode = true
+	model.input = "aй"
+
+	model, _ = model.Update(tea.KeyMsg{Type: tea.KeyBackspace})
+	if model.input != "a" {
+		t.Fatalf("input after backspace = %q, want %q", model.input, "a")
+	}
+}
+
+func TestEntriesBackspaceIsRuneSafeInSearchMode(t *testing.T) {
+	model := NewEntriesModel(sampleEntries(1))
+	model.searchMode = true
+	model.input = "тест"
+
+	model, _ = model.Update(tea.KeyMsg{Type: tea.KeyBackspace})
+	if model.input != "тес" {
+		t.Fatalf("input after backspace = %q, want %q", model.input, "тес")
+	}
+}
+
 func TestEntriesDeleteWithConfirmation(t *testing.T) {
 	model := NewEntriesModel(sampleEntries(3))
 	model.SetSize(120, 12)