from ..core import *
from ..oms import Oms

class MemoryOms(Oms):

	def __init__(self):
		self.__current_tenant = None
		self.__instances = dict()
		self.__tenants = dict()
	
	def get_instance_by_key(self, key : InstanceKey):
		return self.__instances[key.to_tuple()]
	
	# def get_instance_by_global_identifier(self, global_identifier : Guid):

	def create_tenant(self, tenant_name : str):
		if tenant_name in self.__tenants:
			raise NameError("tenant with specified name already exists")

		self.__tenants[tenant_name] = TenantReference(tenant_name, None)

	def select_tenant(self, tenant : TenantReference):
		self.__current_tenant = tenant

	def release_tenant(self):
		self.__current_tenant = None

	def get_current_tenant(self):
		return self.__current_tenant

	def get_tenant_by_name(self, tenant_name : str):
		if tenant_name in self.__tenants:
			return self.__tenants[tenant_name]

		return None