"""
`adafruit_blinka` - Runtime utility objects for re-implementation of CircuitPython API
======================================================================================

* Author(s): cefn
"""

class Enum(object):
    """
        Object supporting CircuitPython-style of static symbols
        as seen with Direction.OUTPUT, Pull.UP
    """

    def __repr__(self):
        """
        Assumes instance will be found as attribute of own class.
        Returns dot-subscripted path to instance
        (assuming absolute import of containing package)
        """
        cls = type(self)
        for key in dir(cls):
            if getattr(cls, key) is self:
                return "{}.{}.{}".format(cls.__module__, cls.__qualname__, key)
        return repr(self)

    @classmethod
    def iteritems(cls):
        """
            Inspects attributes of the class for instances of the class
            and returns as key,value pairs mirroring dict#iteritems
        """
        for key in dir(cls):
            val = getattr(cls, key)
            if isinstance(cls, val):
                yield (key, val)


class ContextManaged:
    """An object that automatically deinitializes hardware with a context manager."""
    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        self.deinit()

    def deinit(self):
        """Free any hardware used by the object."""
        pass


class Lockable(ContextManaged):
    """An object that must be locked to prevent collisions on a microcontroller resource."""
    _locked = False

    def try_lock(self):
        """Attempt to grab the lock. Return True on success, False if the lock is already taken."""
        if self._locked:
            return False
        self._locked = True
        return True

    def unlock(self):
        """Release the lock so others may use the resource."""
        if self._locked:
            self._locked = False
        else:
            raise ValueError("Not locked")

def patch_system():
    """Patch modules that may be different due to the platform."""
    import sys
    from adafruit_blinka.agnostic import time
    sys.modules['time'] = time