from lsst.pipe.tasks.processCcd import ProcessCcdTask

import re

def dict_generator(indict, pre=None):

    """Walk through a dictionary and return a list of lists

    Slightly modified from  

    http://stackoverflow.com/questions/12507206/python-recommended-way-to-walk-complex-dictionary-structures-imported-from-json

    The last item in each list is the value.

    """

    pre = pre[:] if pre else []

    if isinstance(indict, dict):

        for key, value in indict.items():

            if isinstance(value, dict) and len(value) > 0:

                for d in dict_generator(value, [key] + pre):

                    yield d

            elif isinstance(value, list) or isinstance(value, tuple):

                for v in value:

                    for d in dict_generator(v, [key] + pre):

                        yield d

            else:

                yield pre + [key, value]

    else:

        yield indict

def search_config(config, key):

    """Returns any config options and values matching key

    Config is instance of a Config object.

    Searching by key name:

        >>> search_config(ProcessCcdTask.ConfigClass(), 'filterMap')

            {'astromRefObjLoader.calibrate.filterMap': {},

             'photoRefObjLoader.calibrate.filterMap': {},

             'refObjLoader.charImage.filterMap': {}}

    Or by task name:

        >>> search_config(ProcessCcdTask.ConfigClass(), 'photoRefObjLoader')

            {'photoRefObjLoader.calibrate.defaultFilter': '',

             'photoRefObjLoader.calibrate.filterMap': {},

             'photoRefObjLoader.calibrate.pixelMargin': 50}    

    No need for exact matches:

        >>> search_config(ProcessCcdTask.ConfigClass(), 'ObjLoader')

            {'astromRefObjLoader.calibrate.defaultFilter': '',

             'astromRefObjLoader.calibrate.filterMap': {},

             'astromRefObjLoader.calibrate.pixelMargin': 50,

             'photoRefObjLoader.calibrate.defaultFilter': '',

             'photoRefObjLoader.calibrate.filterMap': {},

             'photoRefObjLoader.calibrate.pixelMargin': 50,

             'refObjLoader.charImage.defaultFilter': '',

             'refObjLoader.charImage.filterMap': {},

             'refObjLoader.charImage.pixelMargin': 50}    

    """

    # Import 'nan' because otherwise eval command will fail 

    from numpy import nan

    d = eval(str(config))

    lfound = []

    for l in dict_generator(d):

        try:

            for s in l:

                if re.search(key, str(s)):

                    lfound.append(l)

#             if key in l:

#                 lfound.append(l)

        except TypeError:

            pass

    # The last item in each list is the value

    return {'.'.join(l[:-1]):l[-1] for l in lfound}