module Middleman::Sitemap::Queryable::API

def limit(number)
  Query.new(self).limit(number)
end

def offset(number)
  Query.new(self).offset(number)
end

def order_by(field)
  Query.new(self).order_by(field)
end

def select(options={})
  documents = resources.select { |r| !r.raw_data.empty? }
  options[:where].each do |selector, selector_value|
    documents = documents.select do |document|
      next unless document.raw_data.key? selector.attribute
      document_value = document.raw_data[selector.attribute]
      operator = OPERATOR_MAPPING[selector.operator]
      document_value.send operator, selector_value
    end
  end
  if options[:order_by].present?
    order_attribute = options[:order_by].keys.first
    asc_or_desc = options[:order_by].values.first
    documents = documents.select do |document|
      document.raw_data.include? order_attribute
    end
    documents = documents.sort_by do |document|
      document.raw_data[order_attribute]
    end
    documents.reverse! if asc_or_desc == :desc
  end
  documents
end

def where(hash)
  Query.new(self).where(hash)
end