class RuboCop::Cop::Layout::IndentHeredoc

RUBY
something
<<-RUBY.strip_heredoc
# the following code.
# When EnforcedStyle is active_support, bad code is auto-corrected to
# good
RUBY
something
<<~RUBY
# following code.
# When EnforcedStyle is squiggly, bad code is auto-corrected to the
# good
RUBY
something
<<-RUBY
# bad
@example
(e.g. ActiveSupport, Powerpack or Unindent).
use the older rubies, you should introduce some library to your project
In Ruby 2.3 or newer, squiggly heredocs (‘<<~`) should be used. If you
are indented one step.
This cops checks the indentation of the here document bodies. The bodies

def autocorrect(node) 

def autocorrect(node)
  check_style!
  case style
  when :squiggly
    correct_by_squiggly(node)
  else
    correct_by_library(node)
  end
end

def base_indent_level(node) 

def base_indent_level(node)
  base_line_num = node.loc.expression.line
  base_line = processed_source.lines[base_line_num - 1]
  indent_level(base_line)
end

def check_style! 

def check_style!
  case style
  when nil
    raise Warning, "Auto-correction does not work for #{cop_name}. " \
                   'Please configure EnforcedStyle.'
  when :squiggly
    if target_ruby_version < 2.3
      raise Warning, '`squiggly` style is selectable only on Ruby ' \
                     "2.3 or higher for #{cop_name}."
    end
  end
end

def correct_by_library(node) 

def correct_by_library(node)
  lambda do |corrector|
    corrector.replace(node.loc.heredoc_body, indented_body(node))
    corrected = ".#{StripMethods[style]}"
    corrector.insert_after(node.loc.expression, corrected)
  end
end

def correct_by_squiggly(node) 

def correct_by_squiggly(node)
  return if target_ruby_version < 2.3
  lambda do |corrector|
    if heredoc_indent_type(node) == '~'
      corrector.replace(node.loc.heredoc_body, indented_body(node))
    else
      heredoc_beginning = node.loc.expression.source
      corrected = heredoc_beginning.sub(/<<-?/, '<<~')
      corrector.replace(node.loc.expression, corrected)
    end
  end
end

def heredoc_body(node) 

def heredoc_body(node)
  scrub_string(node.loc.heredoc_body.source)
end

def heredoc_indent_type(node)

Returns '~', '-' or nil 
def heredoc_indent_type(node)
  node.source[/^<<([~-])/, 1]
end

def indent_level(str) 

def indent_level(str)
  indentations = str.scan(/^\s*/).reject { |line| line == "\n" }
  indentations.empty? ? 0 : indentations.min_by(&:size).size
end

def indentation_width 

def indentation_width
  @config.for_cop('IndentationWidth')['Width'] || 2
end

def indented_body(node) 

def indented_body(node)
  body = heredoc_body(node)
  body_indent_level = indent_level(body)
  correct_indent_level = base_indent_level(node) + indentation_width
  body.gsub(/^\s{#{body_indent_level}}/, ' ' * correct_indent_level)
end

def message(node) 

def message(node)
  case style
  when :squiggly
    current_indent_type = "<<#{heredoc_indent_type(node)}"
    format(RUBY23_MSG, indentation_width, current_indent_type)
  when nil
    method = "some library(e.g. ActiveSupport's `String#strip_heredoc`)"
    format(LIBRARY_MSG, indentation_width, method)
  else
    method = "`String##{StripMethods[style]}`"
    format(LIBRARY_MSG, indentation_width, method)
  end
end

def on_heredoc(node) 

def on_heredoc(node)
  body = heredoc_body(node)
  return if body =~ /\A\s*\z/
  body_indent_level = indent_level(body)
  if heredoc_indent_type(node) == '~'
    expected_indent_level = base_indent_level(node) + indentation_width
    return if expected_indent_level == body_indent_level
  else
    return unless body_indent_level.zero?
  end
  add_offense(node, :heredoc_body)
end

def style 

def style
  style = super
  return style unless style == :auto_detection
  if target_ruby_version >= 2.3
    :squiggly
  elsif rails?
    :active_support
  end
end