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# Authors: R. W. Ford, A. R. Porter and S. Siso, STFC Daresbury Lab

'''A simple transformation script for the introduction of OpenMP with PSyclone.
In order to use it you must first install PSyclone. See README.md in the
top-level psyclone directory.

Once you have PSyclone installed, this script may be used by doing:

 >>> psyclone -api "nemo" -s ./omp_levels_trans.py traldf_iso.F90

This should produce a lot of output, ending with generated
Fortran.
'''

from psyclone.nemo import NemoKern
from psyclone.psyGen import TransInfo
from psyclone.transformations import TransformationError


def trans(psy):
    ''' Transform a specific Schedule by making all loops
    over levels OpenMP parallel.

    :param psy: the object holding all information on the PSy layer \
                to be modified.
    :type psy: :py:class:`psyclone.psyGen.PSy`

    :returns: the transformed PSy object
    :rtype:  :py:class:`psyclone.psyGen.PSy`

    '''
    # Get the Schedule of the target routine
    sched = psy.invokes.get('tra_ldf_iso').schedule
    # Get the transformation we will apply
    ompt = TransInfo().get_trans_name('OMPParallelLoopTrans')
    # Apply it to each loop over levels containing a kernel
    for loop in sched.loops():
        # TODO loop.kernel method needs extending to cope with
        # multiple kernels
        kernels = loop.walk(NemoKern)
        if kernels and loop.loop_type == "levels":
            try:
                ompt.apply(loop)
            except TransformationError as error:
                print(str(error))
                continue

    # Return the modified psy object
    return psy
