import copy
import operator
from functools import reduce
from contextlib import contextmanager

@contextmanager
def set_properties(obj, **kwargs):
    """A context manager to set, then reset, certain properties of an object.
    
    The first argument is the object, subsequent keyword arguments are properties
    of said object, which are set initially, then reset to their previous values.
    """
    saved_properties = {}
    for k in kwargs.keys():
        try:
            saved_properties[k] = getattr(obj, k)
        except AttributeError:
            print("Warning: could not get {} on {}.  This property will not be restored!".format(k, obj))
    for k, v in kwargs.items():
        setattr(obj, k, v)
    try:
        yield
    finally:
        for k, v in saved_properties.items():
            setattr(obj, k, v)

def axes_to_array(coordinate_dictionary, axis_keys=['x', 'y', 'z'], base_array=None):
    """Takes key-value pairs of a JSON value, and maps onto an array"""
    # If no base array is given
    if not base_array:
        # Create an array of zeros
        base_array = [0]*len(axis_keys)
    else:
        # Create a copy of the passed base_array
        base_array = copy.copy(base_array)

    # Do the mapping
    for axis, key in enumerate(axis_keys):
        if key in coordinate_dictionary:
            base_array[axis] = coordinate_dictionary[key]

    return base_array

def filter_dict(dictionary: dict, keys: list):
	# Get value by recursively applying getitem
	val = reduce(operator.getitem, keys, dictionary)
	
	# Create new dictionary by running reduce on key, val pairs
	out = reduce(lambda x, y: {y: x}, reversed(keys), val)
	
	return out

def entry_by_id(id: str, object_list: list):
    """Return an object from a list, if <object>.id matches id argument."""
    found = None
    for o in object_list:
        if o.id == id:
            found = o
    return found