# Copyright (c) 2007-2008 Pedro Matiello <pmatiello@gmail.com>

#                         Zsolt Haraszti <zsolt@drawwell.net>

#

# Permission is hereby granted, free of charge, to any person

# obtaining a copy of this software and associated documentation

# files (the "Software"), to deal in the Software without

# restriction, including without limitation the rights to use,

# copy, modify, merge, publish, distribute, sublicense, and/or sell

# copies of the Software, and to permit persons to whom the

# Software is furnished to do so, subject to the following

# conditions:

# The above copyright notice and this permission notice shall be

# included in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

# OTHER DEALINGS IN THE SOFTWARE.

"""

Random graph generators for python-graph.

@sort: generate

"""

# Imports

import graph as classes

from random import randint

# Generator

def generate(graph, num_nodes, num_edges, weight_range=(1, 1)):

	"""

	Add nodes and random edges to the graph.

	@type  graph: graph

	@param graph: Graph.

	@type  num_nodes: number

	@param num_nodes: Number of nodes.

	@type  num_edges: number

	@param num_edges: Number of edges.

	@type  weight_range: tuple

	@param weight_range: tuple of two integers as lower and upper limits on randomly generated

	weights (uniform distribution).

	"""

	# Discover if graph is directed or not

 	directed = (type(graph) == classes.digraph)

	# Nodes first

	nodes = xrange(num_nodes)

	graph.add_nodes(nodes)

	# Build a list of all possible edges

	edges = []

        edges_append = edges.append

	for x in nodes:

		for y in nodes:

			if ((directed and x != y) or (x > y)):

				edges_append((x, y))

	# Randomize the list

	for i in xrange(len(edges)):

		r = randint(0, len(edges)-1)

		edges[i], edges[r] = edges[r], edges[i]

		# Add edges to the graph

		min_wt = min(weight_range)

		max_wt = max(weight_range)

	for i in xrange(num_edges):

		each = edges[i]

		graph.add_edge(each[0], each[1], wt = randint(min_wt, max_wt))