Second homework

The second homework was to judge King of the Dot rap battles.

Objective

The task was to determine winner in each battle. Lyrics were taken from Genius.com. The criteria is the number of letters spelled by each participant in the battle. You may also choose name of the participant and your own criteria.

$ NAME=DNA CRITERIA=you ruby kotd.rb

Source code

# kotd.rb
require 'mechanize'
require_relative 'kotd_battle'

class Kotd
  START_PAGE = 'https://genius.com/artists/songs?for_artist_page=117146&id=King-of-the-dot&page=1&pagination=true'.freeze

  attr_reader :links, :name, :criteria

  def initialize(name = nil, criteria = nil)
    @links = []
    @name = name
    @criteria = criteria
    parse_links
  end

  def run
    if @name
      run_by_name
    else
      run_all
    end
  end

  private

  def parse_links
    puts 'Initializing...'
    puts
    agent = Mechanize.new
    page = agent.get(START_PAGE)
    page.links_with(href: /\w+-lyrics/).each { |link| @links << link }
    next_page = page.links_with(class: 'next_page').first
    while next_page
      page = next_page.click
      page.links_with(href: /\w+-lyrics/).each { |link| @links << link }
      next_page = page.links_with(class: 'next_page').first
    end
  end

  def run_all
    @links.each do |link|
      battle = KotdBattle.new(link.click, @criteria)
      puts battle
      puts
    end
  end

  def run_by_name
    wins = 0
    battles = @links.select { |link| link.text.scan(@name).size >= 1 }
    battles.each do |link|
      battle = KotdBattle.new(link.click, @criteria)
      wins += 1 if battle.winners.include?(@name.to_sym)
      puts battle
      puts
    end
    loses = battles.size - wins
    puts @name + ' wins ' + wins.to_s + ' times, loses ' + loses.to_s + ' times'
  end
end

name = ENV['NAME']
criteria = ENV['CRITERIA']
Kotd.new(name, criteria).run

# kotd_battle.rb
require 'mechanize'

class KotdBattle
  attr_reader :title, :lyrics, :uri, :winners, :score

  def initialize(page = nil, criteria = nil)
    @title = ''
    @lyrics = ''
    @count = {}
    @winners = []
    @score = 0
    @criteria = criteria
    return if page.nil?
    init_by_page(page)
    battle
    guess_winner
  end

  def to_s
    str = @title.to_s + ' - ' + @uri.to_s
    if @count
      str += "\n"
      @count.each { |key, value| str += key.to_s + ' - ' + value.to_s + "\n" }
      str += @winners.join(' and ').to_s + ' WINS!' + "\n"
    end
    str
  end

  private

  def init_by_page(page)
    @uri = page.uri
    @title = page.title
    @title.gsub!('King of the Dot –', ' ')
    @title.gsub!('Lyrics | Genius Lyrics', ' ')
    @title.strip!
    @lyrics = page.css('.lyrics').text.strip
    # remove [?]
    @lyrics.gsub!(/\[\?\]/, ' ')
    # remove [...]
    @lyrics.gsub!(/\[\.\.\.\]/, ' ')
    @lyrics.gsub!(/\[…\]/, ' ')
    # remove [*text*]
    @lyrics.gsub!(/\[\*.*?\*\]/, ' ')
  end

  def battle
    round = @lyrics.scan(/\[.*?\]/)
    text = @lyrics.split(/\[.*?\]/)
    text.shift # first element is always "" (zero string)
    (0...round.count).each do |i|
      performer = round[i][1...-1]
      performer.gsub!(/Round\s\d\s?[:|\-|\u2013]*\s*/, ' ')
      performer.strip!
      key = performer.to_sym
      if text[i]
        t = text[i] # duct tape to avoid rubocop "line is too long"
        counter = @criteria ? t.scan(@criteria).count : t.scan(/[A-Za-z]/).count
      end
      if counter
        @count[key] = @count[key] ? @count[key] + counter : counter
      end
    end
  end

  def guess_winner
    return if @count.empty?
    @score = @count.values.max
    @count.each { |key, value| @winners << key if value == @score }
  end
end

Output

$ NAME=DNA CRITERIA=you ruby kotd.rb
Initializing...

AR & Talksic vs DNA & Charron - https://genius.com/King-of-the-dot-ar-and-talksic-vs-dna-and-charron-lyrics
DNA - 22
Charron - 34
Talksic - 0
100 Bulletz - 0
Charron WINS!

A. Ward vs DNA - https://genius.com/King-of-the-dot-a-ward-vs-dna-lyrics
DNA - 47
A. Ward - 50
A. Ward + DNA - 23
A. Ward WINS!

Charron vs DNA - https://genius.com/King-of-the-dot-charron-vs-dna-lyrics
Charron - 61
DNA - 60
Charron WINS!

Dizaster vs DNA - https://genius.com/King-of-the-dot-dizaster-vs-dna-lyrics
Dizaster - 254
DNA - 292
Diz: DNA's a faggot! - 0
Diz: Canadians are faggots! *Crowd boos* - 5
DNA WINS!

Dizaster vs DNA (2016) - https://genius.com/King-of-the-dot-dizaster-vs-dna-2016-lyrics
DNA - 52
Dizaster - 63
Dizaster WINS!

DNA vs Dirtbag Dan - https://genius.com/King-of-the-dot-dna-vs-dirtbag-dan-lyrics
DNA - 67
Dirtbag Dan - 91
Dirtbag Dan WINS!

DNA vs Eurgh - https://genius.com/King-of-the-dot-dna-vs-eurgh-lyrics
Eurgh - 69
DNA - 91
DNA WINS!

DNA vs Jimz - https://genius.com/King-of-the-dot-dna-vs-jimz-lyrics
Jimz - 67
DNA - 52
Crowd - 0
Jimz WINS!

DNA vs. Rone (2014) - https://genius.com/King-of-the-dot-dna-vs-rone-2014-lyrics
Intro: Organik - 2
DNA - 47
Organik - 0
Rone - 37
DNA WINS!

Illmaculate vs DNA - https://genius.com/King-of-the-dot-illmaculate-vs-dna-lyrics
DNA - 69
Illmaculate - 54
DNA WINS!

The Saurus vs DNA - https://genius.com/King-of-the-dot-the-saurus-vs-dna-lyrics
The Saurus - 41
DNA - 97
DNA WINS!

DNA wins 5 times, loses 6 times

Video

Source files are available on GitHub.