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


"""
Functions for reading and writing graphs.

@sort: read_xml, write_xml, write_dot_graph, write_dot_digraph, write_dot_hypergraph
"""


# Imports
from xml.dom.minidom import Document, parseString


# Values
colors = ['aquamarine4', 'blue4', 'brown4', 'cornflowerblue', 'cyan4',
			'darkgreen', 'darkorange3', 'darkorchid4', 'darkseagreen4', 'darkslategray',
			'deeppink4', 'deepskyblue4', 'firebrick3', 'hotpink3', 'indianred3',
			'indigo', 'lightblue4', 'lightseagreen', 'lightskyblue4', 'magenta4',
			'maroon', 'palevioletred3', 'steelblue', 'violetred3']


# XML

def write_xml(graph):
	"""
	Return a string specifying the given graph as a XML document.
	
	@type  graph: graph
	@param graph: Graph.

	@rtype:  string
	@return: String specifying the graph as a XML document.
	"""

	# Document root
	grxml = Document()
	grxmlr = grxml.createElement('graph')
	grxml.appendChild(grxmlr)

	# Each node...
	for each_node in graph.nodes():
		node = grxml.createElement('node')
		node.setAttribute('id',str(each_node))
		grxmlr.appendChild(node)
		for each_attr in graph.get_node_attributes(each_node):
			attr = grxml.createElement('attribute')
			attr.setAttribute('attr', each_attr[0])
			attr.setAttribute('value', each_attr[1])
			node.appendChild(attr)

	# Each edge...
	for edge_from, edge_to in graph.edges():
		edge = grxml.createElement('edge')
		edge.setAttribute('from',str(edge_from))
		edge.setAttribute('to',str(edge_to))
		edge.setAttribute('wt',str(graph.get_edge_weight(edge_from, edge_to)))
		edge.setAttribute('label',str(graph.get_edge_label(edge_from, edge_to)))
		grxmlr.appendChild(edge)
		for attr_name, attr_value in graph.get_edge_attributes(edge_from, edge_to):
			attr = grxml.createElement('attribute')
			attr.setAttribute('attr', attr_name)
			attr.setAttribute('value', attr_value)
			edge.appendChild(attr)

	return grxml.toprettyxml()


def write_xml_hypergraph(hypergraph):
	"""
	Return a string specifying the given hypergraph as a XML document.
	
	@type  hypergraph: hypergraph
	@param hypergraph: Hypergraph.

	@rtype:  string
	@return: String specifying the graph as a XML document.
	"""

	# Document root
	grxml = Document()
	grxmlr = grxml.createElement('hypergraph')
	grxml.appendChild(grxmlr)

	# Each node...
	nodes = hypergraph.nodes()
	hyperedges = hypergraph.get_hyperedges()
	for each_node in (nodes + hyperedges):
		if (each_node in nodes):
			node = grxml.createElement('node')
		else:
			node = grxml.createElement('hyperedge')
		node.setAttribute('id',str(each_node))
		grxmlr.appendChild(node)

		# and its outgoing edge
		for each_edge in hypergraph.get_links(each_node):
			edge = grxml.createElement('link')
			edge.setAttribute('to',str(each_edge))
			node.appendChild(edge)

	return grxml.toprettyxml()


def read_xml(graph, string):
	"""
	Read a graph from a XML document. Nodes and edges specified in the input will be added to the current graph.
	
	@type  graph: graph
	@param graph: Graph

	@type  string: string
	@param string: Input string in XML format specifying a graph.
	"""
	dom = parseString(string)
	
	# Read nodes...
	for each_node in dom.getElementsByTagName("node"):
		graph.add_node(each_node.getAttribute('id'))
		for each_attr in each_node.getElementsByTagName("attribute"):
			graph.add_node_attribute(each_node.getAttribute('id'), (each_attr.getAttribute('attr'),
				each_attr.getAttribute('value')))

	# Read edges...
	for each_edge in dom.getElementsByTagName("edge"):
		graph.add_edge(each_edge.getAttribute('from'), each_edge.getAttribute('to'), \
			wt=float(each_edge.getAttribute('wt')), label=each_edge.getAttribute('label'))
		for each_attr in each_edge.getElementsByTagName("attribute"):
			attr_tuple = (each_attr.getAttribute('attr'), each_attr.getAttribute('value'))
			if (attr_tuple not in graph.get_edge_attributes(each_edge.getAttribute('from'), \
				each_edge.getAttribute('to'))):
				graph.add_edge_attribute(each_edge.getAttribute('from'), \
					each_edge.getAttribute('to'), attr_tuple)


def read_xml_hypergraph(hypergraph, string):
	"""
	Read a graph from a XML document. Nodes and hyperedges specified in the input will be added to the current graph.
	
	@type  hypergraph: hypergraph
	@param hypergraph: Hypergraph

	@type  string: string
	@param string: Input string in XML format specifying a graph.
	"""
	dom = parseString(string)
	for each_node in dom.getElementsByTagName("node"):
		hypergraph.add_nodes(each_node.getAttribute('id'))
	for each_node in dom.getElementsByTagName("hyperedge"):
		hypergraph.add_hyperedges(each_node.getAttribute('id'))
	dom = parseString(string)
	for each_node in dom.getElementsByTagName("node"):
		for each_edge in each_node.getElementsByTagName("link"):
			hypergraph.link(each_node.getAttribute('id'), each_edge.getAttribute('to'))


# DOT Language

def _dot_node_str(graph, node, wt):
	line = '\t"%s" [ ' % str(node)
	attrlist = graph.get_node_attributes(node)
	for each in attrlist:
		attr = '%s="%s" ' % (each[0], each[1])
		line = line + attr
	line = line + ']\n'
	return line


def _dot_edge_str(graph, u, v, wt):
	line = '\t"%s" -- "%s" [ ' % (str(u), str(v))
	attrlist = graph.get_edge_attributes(u, v) + [('label',graph.get_edge_label(u, v))]
	for each in attrlist:
		attr = '%s="%s" ' % (each[0], each[1])
		line = line + attr
	line = line + ']\n'
	return line


def _dot_arrow_str(graph, u, v, wt):
	line = '\t"%s" -> "%s" [ ' % (str(u), str(v))
	attrlist = graph.get_edge_attributes(u, v) + [('label',graph.get_edge_label(u, v))]
	for each in attrlist:
		attr = '%s="%s" ' % (each[0], each[1])
		line = line + attr
	line = line + ']\n'
	return line


def write_dot_graph(graph, wt):
	"""
	Return a string specifying the given graph in DOT Language.
	
	@type  graph: graph
	@param graph: Graph.

	@type  wt: boolean
	@param wt: Whether edges should be labelled with its weight.

	@rtype:  string
	@return: String specifying the graph in DOT Language.
	"""
	doc = 'graph graphname \n{\n'
	for node in graph:
		doc = doc + _dot_node_str(graph, node, wt)
		for edge in graph[node]:
			if (node >= edge):
				doc = doc + _dot_edge_str(graph, node, edge, wt)
	doc = doc + '}'
	return doc


def write_dot_digraph(graph, wt):
	"""
	Return a string specifying the given digraph in DOT Language.
	
	@type  graph: graph
	@param graph: Graph.

	@type  wt: boolean
	@param wt: Whether arrows should be labelled with its weight.

	@rtype:  string
	@return: String specifying the graph in DOT Language.
	"""
	doc = 'digraph graphname \n{\n'
	for node in graph:
		doc = doc + _dot_node_str(graph, node, wt)
		for edge in graph[node]:
			doc = doc + _dot_arrow_str(graph, node, edge, wt)
	doc = doc + '}'
	return doc


def write_dot_hypergraph(hypergraph, coloured=False):
	"""
	Return a string specifying the given hypergraph in DOT Language.
	
	@type  hypergraph: hypergraph
	@param hypergraph: Hypergraph.
	
	@type  coloured: boolean
	@param coloured: Whether hyperedges should be coloured.

	@rtype:  string
	@return: String specifying the hypergraph in DOT Language.
	"""
	# Start document
	doc = ""
	doc = doc + "graph graphname" + "\n{\n"
	colortable = {}
	colorcount = 0


	# Add hyperedges
	color = ''
	for each_hyperedge in hypergraph.hyperedges():
		colortable[each_hyperedge] = colors[colorcount % len(colors)]
		colorcount = colorcount + 1
		if (coloured):
			color = " color=%s" % colortable[each_hyperedge]
		vars = {
			'hyperedge' : str(each_hyperedge),
			'color' : color
		}
		doc = doc + '\t"%(hyperedge)s" [shape=point %(color)s]\n' % vars
	
	color = "\n"
	# Add nodes and links
	for each_node in hypergraph.nodes():
		doc = doc + "\t\"%s\"\n" % str(each_node)
		for each_link in hypergraph.links(each_node):
			if (coloured):
				color = " [color=%s]\n" % colortable[each_link]
			linkvars = {
				'node' : str(each_node),
				'hyperedge' : str(each_link)
			}
			doc = doc + '\t %(node)s -- %(hyperedge)s' % linkvars + color

	doc = doc + "}"
	return doc