require 'ostruct'

# An adapter class that conforms a Pops model instance + adapters to the
# interface expected by YARD handlers.
#
# FIXME: Inhertiting from OpenStruct is a bit of a hack. It allows attributes
# to be declared as needed but in the long run understandibility of the code
# would be improved by having a concrete model.
class PuppetX::PuppetLabs::Strings::Pops::YARDStatement < OpenStruct
  attr_reader :pops_obj, :comments

  def initialize(pops_obj)
    # Initialize OpenStruct
    super({})

    unless pops_obj.is_a? Puppet::Pops::Model::PopsObject
      raise ArgumentError, "A YARDStatement can only be initialized from a PopsObject. Got a: #{pops_obj.class}"
    end

    @pops_obj = pops_obj
    @pos_adapter = Puppet::Pops::Adapters::SourcePosAdapter.adapt(@pops_obj)
    # FIXME: Perhaps this should be a seperate adapter?
    @comments = extract_comments
  end

  def type
    pops_obj.class
  end

  def line
    @line ||= @pos_adapter.line
  end

  def source
    @source ||= @pos_adapter.extract_text
  end

  # FIXME: I don't know quite what these are supposed to do, but they show up
  # quite often in the YARD handler code. Figure out whether they are
  # necessary.
  alias_method :show, :source
  def comments_hash_flag; nil end
  def comments_range; nil end

  private
  # TODO: This stuff should probably be part of a separate class/adapter.
  COMMENT_PATTERN = /^\s*#.*\n/

  def extract_comments
    comments = []
    program = pops_obj.eAllContainers.find {|c| c.is_a?(Puppet::Pops::Model::Program) }
    # FIXME: Horribly inefficient. Multiple copies. Generator pattern would
    # be much better.
    source_text = program.source_text.lines.to_a

    source_text.slice(0, line-1).reverse.each do |line|
      if COMMENT_PATTERN.match(line)
        # FIXME: The gsub trims comments, but is extremely optimistic: It
        # assumes only one space separates the comment body from the
        # comment character.
        comments.unshift line.gsub(/^\s*#\s/, '')
      else
        # No comment found on this line. We must be done piecing together a
        # comment block.
        break
      end
    end

    # Stick everything back together.
    comments.join
  end
end