class RuboCop::Cop::Style::LineEndConcatenation

def autocorrect(operator_range)
  # Include any trailing whitespace so we don't create a syntax error.
  operator_range = range_with_surrounding_space(operator_range,
                                                :right,
                                                !:with_newline)
  ->(corrector) { corrector.replace(operator_range, '\\') }
end

def check_token_set(index)
  predecessor, operator, successor = processed_source.tokens[index, 3]
  return unless successor
  return unless CONCAT_TOKEN_TYPES.include?(operator.type)
  return unless standard_string_literal?(predecessor)
  return unless standard_string_literal?(successor)
  return if operator.pos.line == successor.pos.line
  next_successor = token_after_last_string(successor, index)
  return if next_successor &&
            HIGH_PRECEDENCE_OP_TOKEN_TYPES.include?(next_successor.type)
  add_offense(operator.pos, operator.pos)
end

def investigate(processed_source)
  processed_source.tokens.each_index do |index|
    check_token_set(index)
  end
end

def standard_string_literal?(token)
  case token.type
  when SIMPLE_STRING_TOKEN_TYPE
    true
  when *COMPLEX_STRING_EDGE_TOKEN_TYPES
    QUOTE_DELIMITERS.include?(token.text)
  else
    false
  end
end

def token_after_last_string(successor, base_index)
  index = base_index + 3
  begin_token, end_token = COMPLEX_STRING_EDGE_TOKEN_TYPES
  if successor.type == begin_token
    ends_to_find = 1
    while ends_to_find > 0
      case processed_source.tokens[index].type
      when begin_token then ends_to_find += 1
      when end_token then ends_to_find -= 1
      end
      index += 1
    end
  end
  processed_source.tokens[index]
end