feat: add genre filtering and longest streak display in TopSongs

src/main/scala/TopSongs/TopSongs.scala

@@ -31,7 +31,11 @@ enum MusicGenre:
   case Rock, Soul, Blues, Folk, Funk, Reggae, HipHop, NewWave, Electro, Metal
 
 // Define an Album with a union between a String and a MusicGenre
-class Album(title: String, label: String, genre: String|MusicGenre)
+class Album(title: String, label: String, genre: String|MusicGenre) {
+  def getGenre(): String | MusicGenre = {
+     genre
+  }
+}
 
 class Streak(val s: String) {
   val streak: Option[Int] = {
@@ -102,20 +106,33 @@ case class TopSongs(songs: List[Song] = List()) {
     })
   }
 
+  // This function filter the songs by a specific music gender
+  def filterByGenre(genre: MusicGenre): List[Song] = {
+    songs.filter(song => song.album.exists(_.getGenre() == genre))
+  }
+
   // 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] = {
+  def countSongsByArtist(): Map[String, Int] = {
     songs.flatMap(_.singer.map(_.person.name))
       .groupBy(identity)
       .view.mapValues(_.size)
       .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(songs: List[Song], n: Int): List[Song] = {
+  def topNSongsByWeeks(n: Int): List[Song] = {
     songs.sortBy(song => -song.rank._1.streak.getOrElse(0)).take(n)
   }
 
@@ -156,19 +173,25 @@ case class TopSongs(songs: List[Song] = List()) {
   // print the songs
   topSongs.printSongs()
 
-  println("----------");
+  println("----------")
 
   // print the number of songs by artist
-  val songsByArtist = topSongs.countSongsByArtist(topSongs.songs)
+  val songsByArtist = topSongs.countSongsByArtist()
   println("Number of songs by artist:")
   songsByArtist.foreach {
     case (artist, count) => println(s"$artist: $count")
   }
 
-  println("----------");
+  println("----------")
+
+  // print the longest streak
+  val longestStreakSong = topSongs.longestStreak()
+  println(s"Longest streak: ${longestStreakSong.title} by ${longestStreakSong.singer.map(_.person.name).mkString(", ")} - ${longestStreakSong.rank._1.streak.getOrElse(0)} weeks")
+
+  println("----------")
 
   // print the top N songs by weeks on chart
-  val topNSongs = topSongs.topNSongsByWeeks(topSongs.songs, 5)
+  val topNSongs = topSongs.topNSongsByWeeks(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")