module RuboCop::Cop::StatementModifier

def body_length(body)
  body.source_range ? body.source_range.size : 0
end

def comment_lines
  @comment_lines ||= processed_source.comments.map { |c| c.location.line }
end

def commented?(source)
  comment_lines.include?(source.line)
end

def empty_body?(body)
  !body || body_length(body).zero?
end

def length_in_modifier_form(node, cond, body_length)
  indentation = node.loc.keyword.column
  kw_length = node.loc.keyword.size
  cond_length = cond.source_range.size
  space = 1
  indentation + body_length + space + kw_length + space + cond_length
end

def line_count(node)
  node.source.lines.grep(/\S/).size
end

def max_line_length
  cop_config['MaxLineLength'] ||
    config.for_cop('Metrics/LineLength')['Max']
end

def modifier_fits_on_single_line?(node)
  modifier_length = length_in_modifier_form(node, node.condition,
                                            body_length(node.body))
  modifier_length <= max_line_length
end

def non_eligible_body?(body)
  empty_body?(body) || body.begin_type? || commented?(body.source_range)
end

def non_eligible_condition?(condition)
  condition.each_node.any?(&:lvasgn_type?)
end

def non_eligible_node?(node)
  line_count(node) > 3 ||
    !node.modifier_form? && commented?(node.loc.end)
end

def single_line_as_modifier?(node)
  return false if non_eligible_node?(node) ||
                  non_eligible_body?(node.body) ||
                  non_eligible_condition?(node.condition)
  modifier_fits_on_single_line?(node)
end