#. -*- coding: utf-8
#
# helper functions

from copy import deepcopy
import functools

def dict_merge(target, *args):
    """ Recursively merges mutiple dicts """
    # Merge multiple dicts
    if len(args) > 1:
        for obj in args:
            dict_merge(target, obj)
        return target
     
    # Recursively merge dicts and set non-dict values
    obj = args[0]
    if not isinstance(obj, dict):
        return obj
    for k, v in obj.items():
        if k in target and isinstance(target[k], dict):
            dict_merge(target[k], v)
        else:
            target[k] = deepcopy(v)
    return target

def get_rec(search_dict, field):
    """
    Takes a dict with nested lists and dicts,
    and searches all dicts for a key of the field
    provided.
    """
    fields_found = []

    for key, value in search_dict.items():
        if key == field:
            fields_found.append(value)

        elif isinstance(value, dict):
            results = get_rec(value, field)
            for result in results:
                fields_found.append(result)

        elif isinstance(value, list):
            for item in value:
               if isinstance(item, dict):
                    more_results = get_recursively(item, field)
                    for another_result in more_results:
                        fields_found.append(another_result)

    return fields_found


def gen_dict_extract(key, var):
    if hasattr(var,'iteritems'):
        for k, v in var.iteritems():
            if k == key:
                yield v
            if isinstance(v, dict):
                for result in gen_dict_extract(key, v):
                    yield result
            elif isinstance(v, list):
                for d in v:
                    for result in gen_dict_extract(key, d):
                        yield result


def chained_get(dct, *keys):
    SENTRY = object()
    def getter(level, key):
        return 'NA' if level is SENTRY else level.get(key, SENTRY)
    return functools.reduce(getter, keys, dct)