# Subroutines allow you to build reusable blocks of TML code that return some result back to
# your main TML source.
#
# If you are able to make use of Subroutines to fill a role that Widgets don't already fill,
# let me know so that I have a reason to keep this code around, because I'm considering removing
# this from RTML.
#
class Rtml::Widgets::Subroutine < Rtml::Widget
  affects :document, :element
  entry_point :subroutine, :call, :subroutine?
  disable_subprocessing!
  shared :subroutines => HashWithIndifferentAccess

  def subroutine(name, options = { }, &block)
    #return document.subroutine(name, options, &block) if document != parent

    subroutines[name] = Rtml::HighLevel::Subroutine.new(name, parent, options, &block)
  end

  def subroutine?(name)
    name = name.to_s if name.kind_of?(Symbol)
    return true if subroutines.key?(name)
    return true if parent != document && parent.parent.subroutine?(name)
    false
  end

  def call(name, arguments = {})
    raise Rtml::Errors::ProcessingError, "Can only call a subroutine from within a screen" unless parent.name == 'screen'
    #return document.call(name, arguments) if document != parent
    name = name.to_s if name.kind_of?(Symbol)
    doc = document
    p = parent
    document.string :rtml_sub_return_val
    while p == doc || p.respond_to?(:parent)
      #unless p.subroutines
      #  raise "No subroutines hash for #{p.inspect}"
      #end
      if p.subroutines && p.subroutines.key?(name)
        return_value = p.subroutines[name].call(parent, arguments)
        begin
          parent.set :rtml_sub_return_val => return_value
        rescue ArgumentError
          parent.set :rtml_sub_return_val => ''
        end
        return parent.terminal_variables[:rtml_sub_return_val]
      end
      raise NoMethodError, "Subroutine does not exist: #{name}" if p == doc
      raise Rtml::Errors::ProcessingError, "Parent of #{p.inspect} is nil" unless p.parent
      p = p.parent
    end

    raise Rtml::Errors::ProcessingError, "Found a parent that is not a parent...? (this shouldn't happen)"
  end
end