refactor(Exporter): extract LRC time formatting to utils/time

Author: Agions

src/core/Exporter.ts

@@ -12,7 +12,7 @@
 
 import { type SubtitleItem } from '@/types/subtitle'
 import { type ExportFormat } from '@/types/subtitle'
-import { _decomposeWithRemainder } from '@/utils/time'
+import { _decomposeWithRemainder, formatTimeLrc } from '@/utils/time'
 
 // ─── 模块级常量（避免每调用重建）───────────────────────────────
 // ASS escape sequences — MUST process backslash FIRST to avoid double-escaping
@@ -183,10 +183,7 @@ function formatLRC(subs: SubtitleItem[]): string {
 
 `
   const content = subs.map(sub => {
-    const min = Math.floor(sub.startTime / 60)
-    const sec = Math.floor(sub.startTime % 60)
-    const ms = Math.floor((sub.startTime % 1) * 100)
-    return `[${pad2(min)}:${pad2(sec)}.${pad2(ms)}]${sub.text}`
+    return `${formatTimeLrc(sub.startTime)}${sub.text}`
   }).join('\n\n')
 
   return `${header}${content}`

src/utils/time.ts

@@ -115,6 +115,17 @@ export function formatTimePrecise(seconds: number): string {
   return `${mins.toString().padStart(2, '0')}:${secs.toString().padStart(2, '0')}.${ms.toString().padStart(3, '0')}`
 }
 
+/**
+ * Format seconds to LRC format ([MM:SS.xx])
+ * Used for .lrc lyric files
+ */
+export function formatTimeLrc(seconds: number): string {
+  const mins = Math.floor(seconds / MINUTES_IN_SECONDS)
+  const secs = Math.floor(seconds % MINUTES_IN_SECONDS)
+  const cs = Math.floor((seconds % 1) * 100)
+  return `[${_pad2(mins)}:${_pad2(secs)}.${_pad2(cs)}]`
+}
+
 /**
  * Format frame number with thousand separators
  */