class Mongoid::Document::OrmAdapter

def column_names
  klass.fields.keys
end

def conditions_to_fields(conditions)
  conditions.inject({}) do |fields, (key, value)|
    if value.is_a?(Mongoid::Document) && klass.fields.keys.include?("#{key}_id")
      fields.merge("#{key}_id" => value.id)
    elsif key.to_s == 'id'
      fields.merge('_id' => value)
    else
      fields.merge(key => value)
    end
  end
end

def create!(attributes = {})
  klass.create!(attributes)
end

def destroy(object)
  object.destroy if valid_object?(object)
end

def find_all(options = {})
  conditions, order, limit, offset = extract_conditions!(options)
  klass.where(conditions_to_fields(conditions)).order_by(order).limit(limit).offset(offset)
end

def find_first(options = {})
  conditions, order = extract_conditions!(options)
  klass.limit(1).where(conditions_to_fields(conditions)).order_by(order).first
end

def get(id)
  klass.where(:_id => wrap_key(id)).first
end

def get!(id)
  klass.find(wrap_key(id))
end