class OrmAdapter::ActiveRecord

def column_names
  klass.column_names
end

def conditions_to_fields(conditions)
  fields = {}
  conditions.each do |key, value|
    if value.is_a?(::ActiveRecord::Base) && (assoc = klass.reflect_on_association(key.to_sym)) && assoc.belongs_to?
      if ::ActiveRecord::VERSION::STRING < "3.1"
        fields[assoc.primary_key_name] = value.send(value.class.primary_key)
        fields[assoc.options[:foreign_type]] = value.class.base_class.name.to_s if assoc.options[:polymorphic]
      else # >= 3.1
        fields[assoc.foreign_key] = value.send(value.class.primary_key)
        fields[assoc.foreign_type] = value.class.base_class.name.to_s if assoc.options[:polymorphic]
      end
    else
      fields[key] = value
    end
  end
  fields
end

def construct_relation(relation, options)
  conditions, order, limit, offset = extract_conditions!(options)
  relation = relation.where(conditions_to_fields(conditions))
  relation = relation.order(order_clause(order)) if order.any?
  relation = relation.limit(limit) if limit
  relation = relation.offset(offset) if offset
  relation
end

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

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

def find_all(options = {})
  construct_relation(klass, options)
end

def find_first(options = {})
  construct_relation(klass, options).first
end

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

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

def order_clause(order)
  order.map {|pair| "#{pair[0]} #{pair[1]}"}.join(",")
end