might_i_recommend.rb

# From https://gist.github.com/Schwad/44f01093e4fe7d8a083a0bc2ac246918
#
# Given Data:
# https://gist.githubusercontent.com/Schwad/9938bc64a88727a3ab2eaaf9ee63c99a/raw/6519e28c85820caac2684cfbec5fe4af33f179a4/rows_of_sweet_jams.csv
#
# Output:
# - Has the blog URLs as key values
# - Each blog URL key points to nested arrays.
# - The arrays each have a list of filenames and kilobyte values of songs found on that website.
# - An array's total megabytes cannot exceed 120. (This is the limit when burning an 80 minute audio CD!)

require "csv"
require "debug"
require "pp"

class MightIRecommend
  attr_reader :list

  def initialize(csv)
    @list = CSV.parse(csv, headers: true)
  end

  def to_s
    to_songs.group_by { |song| song.url }.map do |url, songs|
      [
        url,
        Albumator.new(songs, album_type: MixTape).to_albums
      ]
    end.to_h
  end

  private

  def to_songs
    list.map do |row|
      Song.new(
        url: row["url"],
        email: row["email"],
        filename: row["filename"],
        size: row["size in kilobytes"]
      )
    end
  end
end

class Albumator
  attr_reader :album_type, :songs

  def initialize(songs = [], album_type:)
    @songs = songs
    @album_type = album_type
  end

  def to_albums
    [].tap do |albums|
      albums << album_type.new

      songs.each do |song|
        added = albums.last << song
        unless added
          albums << album_type.new
          albums.last << song
        end
      end
    end
  end
end

class MixTape
  MAX_BYTES = 120_000_000

  attr_reader :album

  def initialize
    @album = []
  end

  #
  # Adds the song to the album (if space is available). Returns false if unable to add to the album.
  #
  def <<(song)
    return false if song.size >= remaining_space
    @album << song
  end

  def inspect
    album.inspect
  end

  def size
    album.map { |song| song.size }.sum
  end

  private

  def remaining_space
    MAX_BYTES - size
  end
end

#<CSV::Row "url":"http://murazik.io/mandi.konopelski" "email":"[email protected]" "filename":"twilight_laser/laborum.mp3" "size in kilobytes":"8107">
class Song
  attr_reader :email, :filename, :size, :url

  def initialize(url:, email:, filename:, size:)
    @url = url
    @email = email
    @filename = filename
    @size = size.to_i * 1000 # convert KB to Bytes
  end

  def inspect
    [filename, size]
  end
end

URL = %{https://gist.githubusercontent.com/Schwad/9938bc64a88727a3ab2eaaf9ee63c99a/raw/6519e28c85820caac2684cfbec5fe4af33f179a4/rows_of_sweet_jams.csv}

pp MightIRecommend.new(`curl --silent #{URL}`).to_s