class RuboCop::Cop::Corrector

def self.source_buffer(source)
  source = source.processed_source if source.respond_to?(:processed_source)
  source = source.buffer if source.respond_to?(:buffer)
  source = source.source_buffer if source.respond_to?(:source_buffer)
  unless source.is_a? ::Parser::Source::Buffer
    raise TypeError, 'Expected argument to lead to a Parser::Source::Buffer ' \
                     "but got #{source.inspect}"
  end
  source
end

def check_range_validity(node_or_range)
  super(to_range(node_or_range))
end

def initialize(source)
  source = self.class.source_buffer(source)
  super(
    source,
    different_replacements: :raise,
    swallowed_insertions: :raise,
    crossing_deletions: :accept
  )
  # Don't print warnings to stderr if corrections conflict with each other
  diagnostics.consumer = NOOP_CONSUMER
end

def remove_leading(node_or_range, size)
  range = to_range(node_or_range)
  to_remove = range.with(end_pos: range.begin_pos + size)
  remove(to_remove)
end

def remove_preceding(node_or_range, size)
  range = to_range(node_or_range)
  to_remove = range.with(
    begin_pos: range.begin_pos - size,
    end_pos:   range.begin_pos
  )
  remove(to_remove)
end

def remove_trailing(node_or_range, size)
  range = to_range(node_or_range)
  to_remove = range.with(begin_pos: range.end_pos - size)
  remove(to_remove)
end

def to_range(node_or_range)
  range = case node_or_range
          when ::RuboCop::AST::Node, ::Parser::Source::Comment
            node_or_range.loc.expression
          when ::Parser::Source::Range
            node_or_range
          else
            raise TypeError,
                  'Expected a Parser::Source::Range, Comment or ' \
                  "Rubocop::AST::Node, got #{node_or_range.class}"
          end
  validate_buffer(range.source_buffer)
  range
end

def validate_buffer(buffer)
  return if buffer == source_buffer
  unless buffer.is_a?(::Parser::Source::Buffer)
    # actually this should be enforced by parser gem
    raise 'Corrector expected range source buffer to be a ' \
          "Parser::Source::Buffer, but got #{buffer.class}"
  end
  raise "Correction target buffer #{buffer.object_id} " \
        "name:#{buffer.name.inspect}" \
        " is not current #{@source_buffer.object_id} " \
        "name:#{@source_buffer.name.inspect} under investigation"
end