feat: add genre filtering and longest streak display in TopSongs

src/main/scala/TopSongs/TopSongs.scala

@@ -122,6 +122,14 @@ case class TopSongs(songs: List[Song] = List()) {
       .toMap
   }
 
+  // This function return the song spent the most weeks on the chart
+  // It uses reduce to find the song with the maximum streak value
+  def longestStreak(): Song = {
+    songs.reduce((s1, s2) => {
+      if (s1.rank._1.streak.getOrElse(0) > s2.rank._1.streak.getOrElse(0)) s1 else s2
+    })
+  }
+
   // This function returns the top N songs by weeks on chart
   // It sorts the songs by the streak value in descending order and takes the top N songs
   def topNSongsByWeeks(n: Int): List[Song] = {