import random
import pprint

num_partitions = 4096
max_cluster_size = 128

full_partition_map = [range(0, max_cluster_size) for _ in range(0, num_partitions)]
map(random.shuffle, full_partition_map)

def make_map(nodes):
    cluster_size = len(nodes)
    partition_map = []
    for row in full_partition_map:
        row = filter(lambda i: i < cluster_size, row)
        row = [nodes[i] for i in row]
        row = filter(lambda n: n != None, row)[:replication_factor] # stable
        partition_map.append(row)

    return partition_map

def compare_maps(map1, map2):
    master_change = 0
    replica_change = 0
    for part1, part2 in zip(map1, map2):
        if part1[0] != part2[0]:
            master_change += 1

        for replica1, replica2 in zip(part1[1:], part2[1:]):
            if replica1 != replica2:
                replica_change += 1

    print "Master Change: %d, Replica Change: %d, Total Change: %d"%(master_change, replica_change, master_change + replica_change)

init_nodes = range(100, 104)
replication_factor = 1

print "Start: %s"%(init_nodes)
initial_map = make_map(init_nodes)

add_node = init_nodes[:]
add_node.append(104)
print "\nAdding a node: %s"%(add_node)
add_node_map = make_map(add_node)
compare_maps(initial_map, add_node_map)

remove_node = init_nodes[:]
removed = init_nodes[2]
del remove_node[2]
print "\nRemoved a node: %s"%(remove_node)
remove_node_map = make_map(remove_node)
compare_maps(initial_map, remove_node_map)

remove_node = init_nodes[:]
removed = init_nodes[2]
remove_node[2] = None
print "\nReplace a node with None: %s"%(remove_node)
remove_node_map = make_map(remove_node)
compare_maps(initial_map, remove_node_map)