Done

config/environment.rb

@@ -4,4 +4,6 @@
 module Concerns
 end
 
-require_all 'lib'
+require_relative '../lib/concerns/findable.rb'
+
+require_all 'lib'

lib/artist.rb

@@ -0,0 +1,45 @@
+class Artist 
+  attr_accessor :name, :songs, :genre
+  extend Concerns::Findable
+
+  @@all = []
+
+  def initialize(name)
+    @name = name
+    @songs = []
+  end 
+
+  def self.all
+    @@all
+  end 
+
+  def self.destroy_all
+    @@all.clear
+  end 
+
+  def save
+    @@all << self
+  end 
+
+  def self.create(name)
+    self.new(name).tap do |song|
+      song.save
+    end
+  end 
+
+  #add_song
+  # assigns the current artist to the song's 'artist' property (song belongs to artist)
+  # does not assign the artist if the song already has an artist
+  # adds the song to the current artist's 'songs' collection
+  # does not add the song to the current artist's collection of songs if it already exists therein
+  def add_song(song)
+    song.artist = self unless song.artist == self
+    @songs << song unless @songs.include?(song)
+  end
+
+  def genres 
+    self.songs.map { |song| song.genre }.uniq
+  end 
+
+  @artists
+end 

lib/concerns/findable.rb

@@ -0,0 +1,16 @@
+module Concerns::Findable
+  def find_by_name(name)
+    all.detect {|instance| instance.name == name }
+  end
+
+  def find_or_create_by_name(name)
+    if 
+     self.find_by_name(name)
+     return self.find_by_name(name)
+   else
+      self.create(name)
+    end
+
+  end 
+
+end 

lib/genre.rb

@@ -0,0 +1,33 @@
+class Genre 
+  attr_accessor :name, :songs
+  extend Concerns::Findable
+
+  @@all = []
+
+  def initialize(name)
+    @name = name 
+    @songs = []
+  end 
+
+  def self.all
+    @@all
+  end 
+
+  def self.destroy_all
+    @@all.clear
+  end 
+
+  def save
+    @@all << self
+  end 
+
+  def self.create(name)
+    self.new(name).tap do |song|
+      song.save
+    end    
+  end 
+
+  def artists
+    songs.map { | song| song.artist }.uniq
+  end 
+end 

lib/music_importer.rb

@@ -0,0 +1,18 @@
+require 'pry'
+
+class MusicImporter
+  attr_accessor :path, :files
+
+  def initialize(path)
+    @path = path 
+  end 
+
+  def files 
+   Dir.glob("#{path}/*").map { |file| file.gsub("#{path}/", '') }
+  end
+
+  def import 
+    # binding.pry
+    files.each { |file| Song.create_from_filename(file) }
+  end 
+end 

lib/music_library_controller.rb

@@ -0,0 +1,91 @@
+require 'pry'
+class MusicLibraryController
+
+  def initialize(path = './db/mp3s')
+    MusicImporter.new(path).import
+  end 
+
+  def call 
+    input = ''
+    while input != 'exit'
+      puts "Welcome to your music library!"
+        puts "To list all of your songs, enter 'list songs'."
+      puts "To list all of the artists in your library, enter 'list artists'."
+      puts "To list all of the genres in your library, enter 'list genres'."
+      puts "To list all of the songs by a particular artist, enter 'list artist'."
+      puts "To list all of the songs of a particular genre, enter 'list genre'."
+      puts "To play a song, enter 'play song'."
+      puts "To quit, type 'exit'."
+      puts "What would you like to do?"
+
+      input = gets.strip
+
+      case input 
+      when "list songs"
+        list_songs
+        when "list artists"
+          list_artists
+          when "list genres"
+            list_genres
+            when "list artist"
+              list_songs_by_artist
+              when "list genre"
+                list_songs_by_genre
+                when "play song"
+                  play_song
+                end 
+    end
+  end 
+
+  def list_songs
+    Song.all.sort_by(&:name).each.with_index(1) do |song, index|
+      puts "#{index}. #{song.artist.name} - #{song.name} - #{song.genre.name}"
+    end
+  end
+
+  def list_artists
+    Artist.all.sort_by(&:name).each.with_index(1) do |artist, index|
+      puts "#{index}. #{artist.name}"
+    end
+  end
+
+  def list_genres
+    Genre.all.sort_by(&:name).each.with_index(1) do |genre, index|
+      puts "#{index}. #{genre.name}"
+    end 
+  end
+
+  def list_songs_by_artist
+    puts "Please enter the name of an artist:"
+
+
+    input = gets.strip
+
+    if artist = Artist.find_by_name(input)
+      artist.songs.sort_by(&:name).each.with_index(1) do |song, index|
+      puts "#{index}. #{song.name} - #{song.genre.name}"
+    end
+  end
+  end 
+
+  def list_songs_by_genre
+    puts "Please enter the name of a genre:"
+    input = gets.strip
+
+    if genre = Genre.find_by_name(input)
+      genre.songs.sort_by(&:name).each.with_index(1) do |song, index|
+      puts "#{index}. #{song.artist.name} - #{song.name}"
+    end
+  end
+  end
+
+  def play_song
+    puts "Which song number would you like to play?"
+    input = gets.strip.to_i
+    x = Song.all.length
+    if (1..x).include?(input)
+      song = Song.all.sort_by(&:name)[input-1]
+        puts "Playing #{song.name} by #{song.artist.name}"
+      end
+  end
+end 

lib/song.rb

@@ -0,0 +1,76 @@
+require 'pry'
+
+class Song 
+  attr_accessor :name, :artist, :genre
+
+  @@all = []
+
+  def initialize(name, artist=nil, genre=nil) # can be invoked with optional argument, object to be assigned to property
+    @name = name
+    self.artist = artist if artist
+    self.genre = genre if genre
+  end 
+
+  def self.all 
+    @@all 
+  end 
+
+  def self.destroy_all
+    @@all.clear
+  end
+
+  def save
+    @@all << self
+  end 
+
+  def self.create(name)
+    self.new(name).tap do |song|
+      song.save
+    end
+  end 
+
+  # invokes Artist#add_song to add itself to the artist's collection of songs(artist has many songs)
+  def artist=(artist)
+    if @artist == nil
+      @artist = artist
+    else
+      @artist = @artist
+    end 
+    if self.artist != nil
+      @artist.add_song(self)
+    end
+    @artist
+  end
+
+  def genre=(genre)
+    @genre = genre
+    genre.songs << self unless genre.songs.include?(self)
+  end 
+
+  def self.find_by_name(name)
+    @@all.find {|song| name == song.name }
+  end 
+
+  def self.find_or_create_by_name(name)
+    if 
+     self.find_by_name(name)
+     return self.find_by_name(name)
+   else
+      self.create(name)
+    end
+  end
+
+    def self.new_from_filename(name)
+      artist, song, genre_name = name.split(' - ')
+      fixed_name = genre_name.gsub('.mp3', '')
+      artist = Artist.find_or_create_by_name(artist)
+      genre = Genre.find_or_create_by_name(fixed_name)
+      new(song, artist, genre)
+    end
+
+    def self.create_from_filename(name)
+      # binding.pry
+      new_from_filename(name).save
+    end
+
+end