#!/usr/env python

import io

import os

import MAUS

def main():

    geometry_root_dir = os.getenv('ERIT_ROOT')

    if geometry_root_dir == '':

        err_msg = """

    To run the MAUS install of ERIT_FFAG you need to set the environment variable

        ERIT_ROOT

    to point at the root of your bzr branch.

    """

        raise EnvironmentError(err_msg)

    # This input generates empty spills, to be filled by the beam maker later on

    my_input = MAUS.InputPySpillGenerator()

    # Create an empty array of mappers, then populate it

    # with the functionality you want to use.

    my_map = MAUS.MapPyGroup()

    my_map.append(MAUS.MapPyBeamMaker()) # beam construction

    my_map.append(MAUS.MapCppSimulation())  #  geant4 simulation

    # can specify datacards here or by using appropriate command line calls

    datacards = io.StringIO(u"")

    # Then construct a MAUS output component - filename comes from datacards

    my_output = MAUS.OutputPyJSON()

    # The Go() drives all the components you pass in, then check the file

    # (default simulation.out) for output

    MAUS.Go(my_input, my_map, MAUS.ReducePyDoNothing(), my_output, datacards)

if __name__=="__main__":

    main()