fix(synced-lyrics): merge consecutive empty lines and improve time parsing clarity

Author: robroid

src/plugins/synced-lyrics/parsers/lrc.ts

@@ -55,10 +55,10 @@ export const LRC = {
       const ms2 = milliseconds.padEnd(2, '0').slice(0, 2);
 
       // Convert to ms (xx → xx0)
-      const timeInMs =
-        parseInt(minutes) * 60 * 1000 +
-        parseInt(seconds) * 1000 +
-        parseInt(ms2) * 10;
+      const minutesMs = parseInt(minutes) * 60 * 1000;
+      const secondsMs = parseInt(seconds) * 1000;
+      const centisMs = parseInt(ms2) * 10;
+      const timeInMs = minutesMs + secondsMs + centisMs;
 
       const currentLine: LRCLine = {
         time: `${minutes.padStart(2, '0')}:${seconds.padStart(2, '0')}.${ms2}`,
@@ -89,6 +89,33 @@ export const LRC = {
       });
     }
 
+    // Merge consecutive empty lines into a single empty line
+    {
+      const merged: LRCLine[] = [];
+      for (const line of lrc.lines) {
+        const isEmpty = !line.text || !line.text.trim();
+        if (isEmpty && merged.length > 0) {
+          const prev = merged[merged.length - 1];
+          const prevEmpty = !prev.text || !prev.text.trim();
+          if (prevEmpty) {
+            const prevEnd = Number.isFinite(prev.duration)
+              ? prev.timeInMs + prev.duration
+              : Infinity;
+            const thisEnd = Number.isFinite(line.duration)
+              ? line.timeInMs + line.duration
+              : Infinity;
+            const newEnd = Math.max(prevEnd, thisEnd);
+            prev.duration = Number.isFinite(newEnd)
+              ? newEnd - prev.timeInMs
+              : Infinity;
+            continue;
+          }
+        }
+        merged.push(line);
+      }
+      lrc.lines = merged;
+    }
+
     return lrc;
   },
 };