require "open-uri"

WORD_URL = "http://learncodethehardway.org/words.txt"
WORDS = []

PHRASES = {
  "class ### < ###\nend" =>
       "Make a class named ### that is-a ###.",
  "class ###\n\tdef initialize(@@@)\n\tend\nend" =>
       "class ### has-a initialize that takes @@@ parameters.",
  "class ###\n\tdef ***(@@@)\n\tend\nend" =>
       "class ### has-a function named *** that takes @@@ parameters.",
  "*** = ###.new()" =>
       "Set *** to an instance of class ###.",
  "***.***(@@@)" =>
       "From *** get the *** function, and call it with parameters @@@.",
  "***.*** = '***'" =>
       "From *** get the *** attribute and set it to '***'."
}

PHRASE_FIRST = ARGV[0] == "english"

URI.open(WORD_URL) { |f|
  f.each_line do |word|
    WORDS.push(word.chomp)
  end
}

def craft_names(rand_words, snippet, pattern, caps = false)
  names = snippet.scan(pattern).map do
    word = rand_words.pop
    caps ? word.capitalize : word
  end

  names * 2
end

def craft_params(rand_words, snippet, pattern)
  names = (0...snippet.scan(pattern).length).map do
    param_count = rand(1..3)
    params = (0...param_count).map do |x|
      rand_words.pop
    end
    params.join(", ")
  end

  names * 2
end

def convert(snippet, phrase)
  rand_words = WORDS.sort_by { rand }
  class_names = craft_names(rand_words, snippet, /###/, caps = true)
  other_names = craft_names(rand_words, snippet, /\*\*\*/)
  param_names = craft_params(rand_words, snippet, /@@@/)

  results = []

  [snippet, phrase].each do |sentence|
    # fake class names, also copies sentence
    result = sentence.gsub("###") do |x|
      class_names.pop
    end

    # fake other names
    result.gsub!("***") do |x|
      other_names.pop
    end

    # fake parameter lists
    result.gsub!(/@@@/) do |x|
      param_names.pop
    end

    results.push(result)
  end

  results
end

# keep going until they hit CTRL-D
loop do
  snippets = PHRASES.keys.sort_by { rand }

  snippets.each do |snippet|
    phrase = PHRASES[snippet]
    question, answer = convert(snippet, phrase)

    if PHRASE_FIRST
      question, answer = answer, question
    end

    print question, "\n\n> "
    exit(0) unless $stdin.gets

    puts "\nANSWER: %s\n\n" % answer
  end
end