#!/usr/bin/python2
# attempt to create a graph showing package dependencies 
# in a nice graph

from __future__ import print_function
import os
#import sys
import collections
import argparse
import logging
import re
from time import sleep
import pygraphviz as pgv

pkgs = os.popen("""LANGUAGE=C pacman -Ssq "^libpng$" """).read().strip().split("\n")
print(pkgs)
pkglist = os.popen("LANGUAGE=C pacman -Si").read().strip().split("\n\n")
G = pgv.AGraph(directed=True)
p = re.compile(r"[<>=].*")
for pkg in pkglist:
    lines = pkg.splitlines()
    repo = lines[0][17:]
    name = lines[1][17:]
    depends = lines[8][17:].split()
    for dep in depends:
        if dep != "None":
            dep = p.sub("",dep)
            G.add_edge(dep,name)

all_n = set(G.nodes())
n = set(pkgs)
for pkg in pkgs:
    n |= set(G.successors(pkg))
    n |= set(G.predecessors(pkg))

G.remove_nodes_from(all_n - n)
    

G.write("graph.dot")
#G.draw("graph.svg",prog='dot')