class RuboCop::Cop::Style::SpecialGlobalVars

def autocorrect(node)
  lambda do |corrector|
    global_var, = *node
    while node.parent && node.parent.begin_type? &&
          node.parent.children.one?
      node = node.parent
    end
    corrector.replace(node.source_range, replacement(node, global_var))
  end
end

def english_name_replacement(preferred_name, node)
  return "\#{#{preferred_name}}" if node.begin_type?
  "{#{preferred_name}}"
end

def format_english_message(global_var)
  regular, english = ENGLISH_VARS[global_var].partition do |var|
    NON_ENGLISH_VARS.include? var
  end
  format_message(english, regular, global_var)
end

def format_list(items)
  items.join('` or `')
end

def format_message(english, regular, global_var)
  if !regular.empty? && !english.empty?
    format(MSG_BOTH, format_list(english), format_list(regular),
           global_var)
  elsif !regular.empty?
    format(MSG_REGULAR, format_list(regular), global_var)
  elsif !english.empty?
    format(MSG_ENGLISH, format_list(english), global_var)
  else
    raise 'Bug in SpecialGlobalVars - global var w/o preferred vars!'
  end
end

def message(node)
  global_var, = *node
  if style == :use_english_names
    format_english_message(global_var)
  else
    format(MSG_REGULAR, preferred_names(global_var).first, global_var)
  end
end

def on_gvar(node)
  global_var, = *node
  return unless (preferred = preferred_names(global_var))
  if preferred.include?(global_var)
    correct_style_detected
  else
    opposite_style_detected
    add_offense(node, :expression)
  end
end

def preferred_names(global)
  if style == :use_english_names
    ENGLISH_VARS[global]
  else
    PERL_VARS[global]
  end
end

def replacement(node, global_var)
  parent_type = node.parent && node.parent.type
  preferred_name = preferred_names(global_var).first
  unless [:dstr, :xstr, :regexp].include?(parent_type)
    return preferred_name.to_s
  end
  if style == :use_english_names
    return english_name_replacement(preferred_name, node)
  end
  "##{preferred_name}"
end