#!/usr/bin/env python

#
# find and import a version of 'py' that exists in a parent dir
# of the current working directory. fall back to import a
# globally available version
#
import sys
import os
from os.path import dirname as opd, exists, join, basename, abspath

def searchpy(current):
    while 1:
        last = current
        initpy = join(current, '__init__.py')
        if not exists(initpy):
            pydir = join(current, 'py')
            # recognize py-package and ensure it is importable
            if exists(pydir) and exists(join(pydir, '__init__.py')):
                #for p in sys.path:
                #    if p == current:
                #        return True
                if current != sys.path[0]:  # if we are already first, then ok
                    sys.stderr.write("inserting into sys.path: %s\n" % current)
                    sys.path.insert(0, current)
                return True
        current = opd(current)
        if last == current:
            return False

if not searchpy(abspath(os.curdir)):
    if not searchpy(opd(abspath(sys.argv[0]))):
        if not searchpy(opd(__file__)):
            pass # let's hope it is just on sys.path

import py

if __name__ == '__main__':
    print ("py lib is at %s" % py.__file__)