module Ostend

# File lib/ostend/core.rb, line 2
def self.included(base)
  base.send(:attr_writer, :ostend_attr_type)
  base.send(:attr_writer, :ostend_attr_filter)
  base.send(:attr_writer, :ostend_strict)
  # TODO : set ostend defaults here instead of in ostendify
end

# File lib/ostend/core.rb, line 9
def ostendify( hash )
  @ostend_attr_type ||= :accessor
  @ostend_attr_filter ||= nil
  @ostend_strict ||= false

  ostend_raise_disallowed_attrs( hash ) if @ostend_attr_filter && @ostend_strict
  ostend_create_attributes( hash )
end

# File lib/ostend/core.rb, line 20
def ostend_create_attributes( hash )
  ostend_filterd_hash( hash ).each do |key,value|
    temp_type = @ostend_attr_type
    self.instance_variable_set("@#{key}", value)
    # self.class.send("attr_#{@ostend_attr_type}", key)
    # I'm basically trying to do the above.
    #   However, there is an issue with the above send in that it modifies the core class
    #   We really want to access the instance's single class like below.
    #   I really want this to be simple but it end up being rediculous to modify the singleton class while honoring scoped variables
    #   To get everything I needed into scope I have to retrieve the singleton class
    #   and then class_eval on it.
    #   Also, instance vars don't evaluate so I had to create a temporary value which will properly scope in the class_eval block.
    #   Hlurg
    (class << self; self; end).class_eval do
      send("attr_#{temp_type}", key)
    end
  end
end

# File lib/ostend/core.rb, line 39
def ostend_filterd_hash( hash )
  return hash unless @ostend_attr_filter.respond_to?(:include?)
  hash.keep_if{|key, val| @ostend_attr_filter.include?( key ) }
end

# File lib/ostend/core.rb, line 44
def ostend_raise_disallowed_attrs( hash )
  disallowed_attrs = hash.delete_if{|key, val| @ostend_attr_filter.include?( key ) }
  return if disallowed_attrs.empty?
  raise "The following are not allowed attributes: #{disallowed_attrs}" 
end