class Chainer

# File lib/markovite/chainer.rb, line 11
def initialize(dictionary)
  self.dictionary = dictionary
  @depth = dictionary.depth
  #takes in a dictionary object
  #constructs chain from dictionary object public interface
end

# File lib/markovite/chainer.rb, line 44
def depth=(arg)
  raise "Depth cannot be changed"
end

# File lib/markovite/chainer.rb, line 48
def make_sentence
  raise "No corpus in memory" if dictionary.nil?
  attempts = 0
  while attempts < MAX_ATTEMPTS
    sentence = generate_text
    if is_valid_sentence?(sentence)
      return sentence
    else
      attempts += 1
    end
  end
  nil
end

# File lib/markovite/chainer.rb, line 28
def make_sentence_of_length(how_long)
  begin
    make_sentence_with_block {|sentence| sentence.length <= how_long}
  rescue NoMethodError
    return nil
  end
end

# File lib/markovite/chainer.rb, line 18
def make_sentence_starts_with(phrase)
  chunk = get_chunk(phrase)
  begin
    partial = generate_text(chunk)
  rescue ArgumentError
    return nil
  end
  "#{phrase} #{partial}"
end

# File lib/markovite/chainer.rb, line 36
def make_sentences(amount, condition=true)
  sentences = []
  amount.times do
    sentences << make_sentence
  end
  sentences.join(' ')
end

# File lib/markovite/chainer.rb, line 107
def close_open_quote(sentence)
  if has_open_quote?(sentence)
    "#{sentence}\""
  else
    sentence
  end
end

# File lib/markovite/chainer.rb, line 115
def generate_text(current_chunk = [BEGINNING] * depth)
  sentence = current_chunk
  while current_chunk.last != ENDING
    sentence << pick_next(current_chunk)
    current_chunk = sentence.last(depth)
  end
  remove_markers(sentence)
  sentence = sentence.join(' ')
  close_open_quote(sentence)
end

# File lib/markovite/chainer.rb, line 76
def get_chunk(phrase)
  words = phrase.split(' ')
  chunk = words.last(depth)
  while chunk.size < depth
    chunk.unshift(BEGINNING)
  end
  chunk
end

# File lib/markovite/chainer.rb, line 102
def has_open_quote?(sentence)
  count = sentence.count("\"")
  count.odd?
end

# File lib/markovite/chainer.rb, line 98
def is_valid_sentence?(sentence)
  !dictionary.has_sentence(sentence)
end

# File lib/markovite/chainer.rb, line 64
def make_sentence_with_block
  attempts = 0
  while attempts < MAX_ATTEMPTS
    sentence = make_sentence
    if yield(sentence)
      return sentence
    else
      attempts += 1
    end
  end
end

# File lib/markovite/chainer.rb, line 85
def pick_next(words)
  word_list = dictionary.chain[words]
  raise ArgumentError, "No matching state" if word_list.empty?
  word_list.sample
end

# File lib/markovite/chainer.rb, line 91
def remove_markers(sentence)
  #removes BEGINNING and ENDING markers
  sentence.shift while sentence.first == BEGINNING
  sentence.pop while sentence.last == ENDING
  sentence
end