"""Module implementing error-catching version of send (sendRobust)"""
from dispatcher import Any, Anonymous, liveReceivers, getAllReceivers
from robustapply import robustApply

def sendRobust(
        signal=Any,
        sender=Anonymous,
        *arguments, **named
):
    """Send signal from sender to all connected receivers catching errors

    signal -- (hashable) signal value, see connect for details

    sender -- the sender of the signal

            if Any, only receivers registered for Any will receive
            the message.

            if Anonymous, only receivers registered to receive
            messages from Anonymous or Any will receive the message

            Otherwise can be any python object (normally one
            registered with a connect if you actually want
            something to occur).

    arguments -- positional arguments which will be passed to
            *all* receivers. Note that this may raise TypeErrors
            if the receivers do not allow the particular arguments.
            Note also that arguments are applied before named
            arguments, so they should be used with care.

    named -- named arguments which will be filtered according
            to the parameters of the receivers to only provide those
            acceptable to the receiver.

    Return a list of tuple pairs [(receiver, response), ... ]

    if any receiver raises an error (specifically any subclass of Exception),
    the error instance is returned as the result for that receiver.
    """
    # Call each receiver with whatever arguments it can accept.
    # Return a list of tuple pairs [(receiver, response), ... ].
    responses = []
    for receiver in liveReceivers(getAllReceivers(sender, signal)):
        try:
            response = robustApply(
                    receiver,
                    signal=signal,
                    sender=sender,
                    *arguments,
                    **named
            )
        except Exception, err:
            responses.append((receiver, err))
        else:
            responses.append((receiver, response))
    return responses
