From e649b9ec5401fc432368e0d341380c4e9a64e89c Mon Sep 17 00:00:00 2001
From: vsariola <5684185+vsariola@users.noreply.github.com>
Date: Sat, 8 May 2021 16:40:06 +0300
Subject: [PATCH] fix(gioui): unnamed instruments on tracks with multiple
 voices crashed.

Closes #62.
---
 tracker/gioui/trackeditor.go | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/tracker/gioui/trackeditor.go b/tracker/gioui/trackeditor.go
index f552a6f..3e5bfc6 100644
--- a/tracker/gioui/trackeditor.go
+++ b/tracker/gioui/trackeditor.go
@@ -325,13 +325,27 @@ func (te *TrackEditor) layoutTracks(gtx C, t *Tracker) D {
 		firstIndex, err := t.Song().Patch.InstrumentForVoice(curVoice)
 		lastIndex, err2 := t.Song().Patch.InstrumentForVoice(curVoice + trk.NumVoices - 1)
 		if err == nil && err2 == nil {
-			switch lastIndex - firstIndex {
+			switch diff := lastIndex - firstIndex; diff {
 			case 0:
 				instrName = t.Song().Patch[firstIndex].Name
-			case 1:
-				instrName = string(t.Song().Patch[firstIndex].Name[0]) + "/" + string(t.Song().Patch[lastIndex].Name[0])
 			default:
-				instrName = string(t.Song().Patch[firstIndex].Name[0]) + "/" + string(t.Song().Patch[firstIndex+1].Name[0]) + "..."
+				n1 := t.Song().Patch[firstIndex].Name
+				n2 := t.Song().Patch[firstIndex+1].Name
+				if len(n1) > 0 {
+					n1 = string(n1[0])
+				} else {
+					n1 = "?"
+				}
+				if len(n2) > 0 {
+					n2 = string(n2[0])
+				} else {
+					n2 = "?"
+				}
+				if diff > 1 {
+					instrName = n1 + "/" + n2 + "..."
+				} else {
+					instrName = n1 + "/" + n2
+				}
 			}
 			if len(instrName) > 7 {
 				instrName = instrName[:7]