#!/usr/bin/env python3
#
# Read dgml from stdin, write dot to stdout
# 
import re
import sys
import xml.etree.ElementTree as ET
import argparse

parser = argparse.ArgumentParser(description='Read a dgml file and produce dot output.')
parser.add_argument('-m', '--merge-with', metavar='mergefile', type=str,
                    help='Color nodes found in main and mergefile to distinguish them')
args = parser.parse_args()

mergenodes = set()
if args.merge_with:
    # Form a set of Node Ids to check Node presence later
    mergetree = ET.fromstring(open(args.merge_with, 'rb').read())
    for node in mergetree.find("{http://schemas.microsoft.com/vs/2009/dgml}Nodes"):
        mergenodes.add(node.attrib['Id'])

# Read source
xml = sys.stdin.read()
root = ET.fromstring(xml)

# Form dot element sequence
body_l = ["digraph qlast {",
          "node [shape=box];",
]

for node in root.find("{http://schemas.microsoft.com/vs/2009/dgml}Nodes"):
    att = node.attrib
    keys = set(att.keys()) - set(['Id', 'Label'])
    prop_l = ['{}="{}"'.format(key, att[key]) for key in keys]
    prop_l.append('{}="{}"'.format("label", att["Label"]))
    node_id = att['Id']
    if node_id in mergenodes:
        prop_l.append('color=green')
    node_s = "nd_{} [{}];".format(node_id, ", ".join(prop_l))
    body_l.append(node_s)

for edge in root.find("{http://schemas.microsoft.com/vs/2009/dgml}Links"):
    att = edge.attrib
    edge_s = 'nd_{} -> nd_{} [label="{}"];'.format(
        att["Source"], att["Target"], att.get("Label", ""))
    body_l.append(edge_s)

body_l.append("}")

# Write dot 
sys.stdout.write("\n".join(body_l))