# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


class RoundRobin:
    """
    Round-robin generator for use with `Client.connect()`. Cycles a node
    list until a maximum number of reconnects is reached (if set).
    """

    def __init__(self, nodes: list, max_reconnects: int=None):
        """
        :param nodes: list of two-tuples of (host, port) format,
        :param max_reconnects: (optional) maximum number of reconnect attempts.
         defaults to None (cycle nodes infinitely).
        """
        self.nodes = nodes
        self.max_reconnects = max_reconnects
        self.node_index = 0
        self.reconnects = 0

    def __iter__(self) -> 'RoundRobin':
        return self

    def __next__(self) -> tuple:
        if self.max_reconnects is not None:
            if self.reconnects >= self.max_reconnects:
                raise StopIteration
            else:
                self.reconnects += 1

        if self.node_index >= len(self.nodes):
            self.node_index = 0
        node = self.nodes[self.node_index]
        self.node_index += 1
        return node