From 8a1e2a53357acc8523cda319ce4bc369d6867c75 Mon Sep 17 00:00:00 2001
From: Maxim Vershinin <im@vmn.su>
Date: Thu, 20 Aug 2026 12:47:58 +0500
Subject: [PATCH] FIX: aligns line number with the corresponding lines in the
 tracklist editor

---
 .../src/components/TracklistEditor.tsx        | 53 ++++++++++++++-----
 1 file changed, 41 insertions(+), 12 deletions(-)

diff --git a/web/frontend/src/components/TracklistEditor.tsx b/web/frontend/src/components/TracklistEditor.tsx
index d878f45..3f49bb7 100644
--- a/web/frontend/src/components/TracklistEditor.tsx
+++ b/web/frontend/src/components/TracklistEditor.tsx
@@ -1,4 +1,4 @@
-import React, { useCallback, useEffect, useState } from 'react'
+import React, { useCallback, useEffect, useRef, useState } from 'react'
 import { Box, Paper, TextField, Typography, Alert } from '@mui/material'
 import { useDropzone } from 'react-dropzone'
 import { useTracklistStore } from '../stores/tracklistStore'
@@ -10,6 +10,9 @@ export const TracklistEditor: React.FC = () => {
   const { options } = useOptionsStore()
   const [isDragging, setIsDragging] = useState(false)
 
+  const textAreaRef = useRef<HTMLTextAreaElement>(null)
+  const lineNumbersRef = useRef<HTMLDivElement>(null)
+
   const validate = (text: string) => {
     const result = parseAndValidateTracklist(text, options.tracklist_format)
     setEntries(result.entries)
@@ -23,10 +26,29 @@ export const TracklistEditor: React.FC = () => {
     validate(text)
   }
 
+  const handleScroll = useCallback(() => {
+    if (lineNumbersRef.current && textAreaRef.current) {
+      lineNumbersRef.current.scrollTop = textAreaRef.current.scrollTop
+    }
+  }, [])
+
+  useEffect(() => {
+    const textArea = textAreaRef.current
+    if (textArea) {
+      textArea.addEventListener('scroll', handleScroll)
+      return () => textArea.removeEventListener('scroll', handleScroll)
+    }
+  }, [handleScroll])
+
+  useEffect(() => {
+    if (rawText) {
+      validate(rawText)
+    }
+  }, [options.tracklist_format])
+
   const onDrop = useCallback(
     (acceptedFiles: File[]) => {
       if (acceptedFiles.length === 0) return
-
       const file = acceptedFiles[0]
       const reader = new FileReader()
       reader.onload = (event) => {
@@ -48,13 +70,6 @@ export const TracklistEditor: React.FC = () => {
     multiple: false,
   })
 
-  // Re-validate when tracklist format changes
-  useEffect(() => {
-    if (rawText) {
-      validate(rawText)
-    }
-  }, [options.tracklist_format])
-
   const lineCount = rawText.split('\n').filter(line => line.trim() !== '').length
 
   return (
@@ -82,12 +97,13 @@ export const TracklistEditor: React.FC = () => {
         </Typography>
       </Typography>
 
-      <Box sx={{ display: 'flex', gap: 2 }}>
+      <Box sx={{ display: 'flex', gap: 2, position: 'relative' }}>
         {/* Line numbers column */}
         <Box
+          ref={lineNumbersRef}
           sx={{
             minWidth: 40,
-            maxWidth: 40,
+            maxWidth: 60,  // Allow more space for 3-digit numbers
             fontFamily: 'monospace',
             fontSize: '14px',
             lineHeight: 1.7,
@@ -95,6 +111,11 @@ export const TracklistEditor: React.FC = () => {
             textAlign: 'right',
             userSelect: 'none',
             overflow: 'hidden',
+            paddingTop: '8.5px',
+            paddingBottom: '8.5px',
+            scrollbarWidth: 'none',
+            '&::-webkit-scrollbar': { display: 'none' },
+            whiteSpace: 'nowrap',  // Prevent wrapping of line numbers
           }}
         >
           {rawText.split('\n').map((_, i) => (
@@ -102,7 +123,7 @@ export const TracklistEditor: React.FC = () => {
           ))}
         </Box>
 
-        {/* Editor text area */}
+        {/* Editor text area – now with horizontal scroll and no wrap */}
         <TextField
           multiline
           fullWidth
@@ -112,11 +133,19 @@ export const TracklistEditor: React.FC = () => {
           onChange={handleTextChange}
           placeholder={`Enter your tracklist here...\n\nExample (format: ${options.tracklist_format}):\n00:00 Intro\n01:30 Song One - Artist A\n04:20-06:45 Another Song - Artist B`}
           variant="outlined"
+          inputRef={textAreaRef}
           sx={{
             '& .MuiInputBase-root': {
               fontFamily: 'monospace',
               fontSize: '14px',
               lineHeight: 1.7,
+              overflowX: 'auto',  // Enable horizontal scroll
+            },
+            '& .MuiInputBase-input': {
+              paddingTop: '8.5px',
+              paddingBottom: '8.5px',
+              whiteSpace: 'nowrap',  // Prevent wrapping
+              overflowX: 'auto',
             },
           }}
           error={!isValid && errors.length > 0}