skip tagging if already good (ie lidarr)

src/file_tags.rs

@@ -22,6 +22,7 @@ fn tag_type_for_file(ft: FileType) -> TagType {
 }
 
 /// Write updated metadata back to the music file's embedded tags.
+/// Skips the write if all tags already match (avoids expensive FLAC rewrites).
 pub fn write_tags(
     file_path: &str,
     details: &RecordingDetails,
@@ -46,6 +47,39 @@ pub fn write_tags(
         .cloned()
         .unwrap_or_else(|| lofty::tag::Tag::new(tag_type));
 
+    // Check if all tags already match — skip the expensive write if so
+    let existing_title = tag.title().map(|s| s.to_string());
+    let existing_artist = tag.artist().map(|s| s.to_string());
+    let existing_album = tag.album().map(|s| s.to_string());
+    let existing_year = tag.year();
+    let existing_genre = tag.genre().map(|s| s.to_string());
+
+    let want_album = release.map(|r| r.title.clone());
+    let want_year = year.map(|y| y as u32);
+    let want_genre = genre.map(|g| g.to_string());
+
+    let title_ok = existing_title.as_deref() == Some(&details.title);
+    let artist_ok = existing_artist.as_deref() == Some(&details.artist);
+    let album_ok = match (&existing_album, &want_album) {
+        (Some(e), Some(w)) => e == w,
+        (None, None) => true,
+        _ => false,
+    };
+    let year_ok = existing_year == want_year;
+    let genre_ok = match (&existing_genre, &want_genre) {
+        (Some(e), Some(w)) => e == w,
+        (None, None) => true,
+        _ => false,
+    };
+
+    if title_ok && artist_ok && album_ok && year_ok && genre_ok {
+        tracing::debug!(
+            path = file_path,
+            "file tags already correct, skipping write"
+        );
+        return Ok(());
+    }
+
     // Set metadata
     tag.set_title(details.title.clone());
     tag.set_artist(details.artist.clone());