# from operator import itemgetter
# import heapq


# class Node:
#     def __init__(self, node_id, ip=None, port=None):
#         self.id = node_id  # pylint: disable=invalid-name
#         self.ip = ip  # pylint: disable=invalid-name
#         self.port = port
#         self.long_id = int(node_id.hex(), 16)

#     def same_home_as(self, node):
#         return self.ip == node.ip and self.port == node.port

#     def distance_to(self, node):
#         """
#         Get the distance between this node and another.
#         """
#         return self.long_id ^ node.long_id

#     def __iter__(self):
#         """
#         Enables use of Node as a tuple - i.e., tuple(node) works.
#         """
#         return iter([self.id, self.ip, self.port])

#     def __repr__(self):
#         return repr([self.long_id, self.ip, self.port])

#     def __str__(self):
#         return "%s:%s" % (self.ip, str(self.port))


# class NodeHeap:
#     """
#     A heap of nodes ordered by distance to a given node.
#     """
#     def __init__(self, node, maxsize):
#         """
#         Constructor.

#         @param node: The node to measure all distnaces from.
#         @param maxsize: The maximum size that this heap can grow to.
#         """
#         self.node = node
#         self.heap = []
#         self.contacted = set()
#         self.maxsize = maxsize

#     def remove(self, peers):
#         """
#         Remove a list of peer ids from this heap.  Note that while this
#         heap retains a constant visible size (based on the iterator), it's
#         actual size may be quite a bit larger than what's exposed.  Therefore,
#         removal of nodes may not change the visible size as previously added
#         nodes suddenly become visible.
#         """
#         peers = set(peers)
#         if not peers:
#             return
#         nheap = []
#         for distance, node in self.heap:
#             if node.id not in peers:
#                 heapq.heappush(nheap, (distance, node))
#         self.heap = nheap

#     def get_node(self, node_id):
#         for _, node in self.heap:
#             if node.id == node_id:
#                 return node
#         return None

#     def have_contacted_all(self):
#         return len(self.get_uncontacted()) == 0

#     def get_ids(self):
#         return [n.id for n in self]

#     def mark_contacted(self, node):
#         self.contacted.add(node.id)

#     def popleft(self):
#         return heapq.heappop(self.heap)[1] if self else None

#     def push(self, nodes):
#         """
#         Push nodes onto heap.

#         @param nodes: This can be a single item or a C{list}.
#         """
#         if not isinstance(nodes, list):
#             nodes = [nodes]

#         for node in nodes:
#             if node not in self:
#                 distance = self.node.distance_to(node)
#                 heapq.heappush(self.heap, (distance, node))

#     def __len__(self):
#         return min(len(self.heap), self.maxsize)

#     def __iter__(self):
#         nodes = heapq.nsmallest(self.maxsize, self.heap)
#         return iter(map(itemgetter(1), nodes))

#     def __contains__(self, node):
#         for _, other in self.heap:
#             if node.id == other.id:
#                 return True
#         return False

#     def get_uncontacted(self):
#         return [n for n in self if n.id not in self.contacted]