feat: add function to retrieve top N songs by weeks on chart

src/main/scala/TopSongs/TopSongs.scala

@@ -83,28 +83,42 @@ case class TopSongs(songs: List[Song] = List()) {
     TopSongs(song :: songs)
   }
   def printSongs(): Unit = {
-    songs.foreach(song => {
+    songs.map(song => {
       val title = song.title
       val singer = song.singer
       val producers = song.producer.map(_.create()).mkString(", ")
       val streak = song.rank._1.streak.getOrElse("no")
       val pos = song.rank._2.pos.getOrElse("NA")
 
-      if (singer.exists(a => {
-        a.isInstanceOf[God]
-      })) {
-        println(s"$title by God ${singer.map(_.person.name).mkString(", ")} spent $streak weeks on the charts on Pos. $pos")
-      } else {
-        println(
+      singer match {
+        case s if s.exists(_.person.isInstanceOf[God]) => println(s"$title by God ${singer.map(_.person.name).mkString(", ")} spent $streak weeks on the charts on Pos. $pos")
+        case _ => println(
           s"$title by ${singer.map(_.person.name).mkString(", ")}. " +
             s"$producers this song that " +
             s"spent $streak weeks " +
             s"on the charts on Pos. $pos"
         )
       }
-
     })
   }
+
+  // This function counts the number of songs by each artist
+  // It uses flatMap to extract the artist names from the songs
+  // Then it groups the songs by artist name and counts the occurrences
+  // Finally, it returns a map with the artist names as keys and the counts as values
+  def countSongsByArtist(songs: List[Song]): Map[String, Int] = {
+    songs.flatMap(_.singer.map(_.person.name))
+      .groupBy(identity)
+      .view.mapValues(_.size)
+      .toMap
+  }
+
+  // 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(songs: List[Song], n: Int): List[Song] = {
+    songs.sortBy(song => -song.rank._1.streak.getOrElse(0)).take(n)
+  }
+
 }
 
 @main def main(): Unit =
@@ -141,3 +155,26 @@ case class TopSongs(songs: List[Song] = List()) {
 
   // print the songs
   topSongs.printSongs()
+
+  println("----------");
+
+  // print the number of songs by artist
+  val songsByArtist = topSongs.countSongsByArtist(topSongs.songs)
+  println("Number of songs by artist:")
+  songsByArtist.foreach {
+    case (artist, count) => println(s"$artist: $count")
+  }
+
+  println("----------");
+
+  // print the top N songs by weeks on chart
+  val topNSongs = topSongs.topNSongsByWeeks(topSongs.songs, 5)
+  println("Top N songs by weeks on chart:")
+  topNSongs.foreach { song =>
+    println(s"${song.title} by ${song.singer.map(_.person.name).mkString(", ")} - ${song.rank._1.streak.getOrElse(0)} weeks")
+  }
+
+
+
+
+