class SynchronizePorts(PyScriptObject):
    """
    Description
    -----------
    Using the I{Synchronize Ports} module, you can synchronize ports of two modules of the same type.
    For example, it is particularly useful to control and compare two probes on two different datasets.
    In order to use the module, select the first module to be synchronized, then choose
    I{Animation/Demos/SynchronizePorts} from the popup menu. The new I{Synchronize Ports} module automatically connects
    InputA to the selected module. Finally, connect the InputB port to the second module to be synchronized.
    Alternatively, you can also connect the InputA and InputB ports of the module by hand.

    Connections
    -----------
    Input a [required]
    ~~~~~~~
    First module to synchronize

    Input b [required]
    ~~~~~~~
    Second module to synchronize. NOTE: the connected module should be of the same type as the first connected module.
    """
    def __init__(self):
        self.__connections = []           #name of ports linked between two modules
        self.__data_a = None              #Handle of object connected to input A
        self.__data_b = None              #Handle of object connected to input B

        self.ports.data.visible = False
        self.port_input_a = HxConnection(self, "port_input_a", "Input A")
        self.port_input_a.valid_types = ['HxModule']

        self.port_input_b = HxConnection(self, "port_input_b", "Input B")
        self.port_input_b.valid_types = ['HxModule']

    def __del__(self):
        self.__disconnect_all()
        self.ports.data.visible = True

    def update(self):
        if ((self.port_input_a.source() == None) or
            (self.port_input_b.source() == None) or
            ( (self.__data_a != None) and (not self.__data_a.is_same_object(self.port_input_a.source())) ) or
            ( (self.__data_b != None) and (not self.__data_b.is_same_object(self.port_input_b.source())) ) ):
            self.__disconnect_all()
        PyScriptObject.update(self)

    def compute(self):
        self.__data_a = self.port_input_a.source()
        self.__data_b = self.port_input_b.source()
        if ( ( (self.port_input_a.source() !=  None) ) or
             ( (self.port_input_b.source() !=  None) ) or
             ( (self.__data_a != None) and (not self.__data_a.is_same_object(self.port_input_a.source())) ) or
             ( (self.__data_b != None) and (not self.__data_b.is_same_object(self.port_input_b.source())) ) ):
            self.__disconnect_all()
            self.__connect_all()
        PyScriptObject.compute(self)

    def __connect_all(self):
        #Links common ports in the modules connected to two inputs A and B
        self.__connections = []

        if (self.__data_a ==  None) or (self.__data_b ==  None):
            return
        for portname in self.__data_a.portnames:
            if not hasattr(self.__data_a.ports,portname):
                continue
            portA = getattr(self.__data_a.ports,portname)
            if isinstance(portA, HxConnection):
                continue
            portB = getattr(self.__data_b.ports,portname)
            try:
                portA.link(portB)
                self.__data_a.fire()
                self.__connections.append(portname)
            except TypeError:
                continue

    def __disconnect_all(self):
        #Unlinks common ports in the two modules
        if (self.__data_a !=  None) and (self.__data_b !=  None):
            for portname in self.__connections:
                portA = getattr(self.__data_a.ports,portname)
                portB = getattr(self.__data_b.ports,portname)
                portA.unlink(portB)
            self.__connections=[]