#!/usr/bin/python
# vi: ts=4 expandtab

import os
import sys
import re

def parse_versions(fn):
    with open(fn, 'r') as fh:
        lines = fh.read().splitlines()
    versions = []
    for line in lines:
        line = line.strip()
        if line.startswith("-") or not line:
            continue
        if not re.match(r"[\d]", line):
            continue
        line = line.strip(":")
        if (re.match(r"^[\d+]\.[\d+]\.[\d+]$", line) or
            re.match(r"^[\d+]\.[\d+]$", line)):
            versions.append(line)
    return versions

def find_changelog(args):
    p_files = []
    if args:
        p_files.append(args[0])
    p_files.append(os.path.join(os.pardir, "ChangeLog"))
    p_files.append(os.path.join(os.getcwd(), 'ChangeLog'))
    found = None
    for fn in p_files:
        if os.path.isfile(fn):
            found = fn
            break
    return found


if __name__ == '__main__':
    run_args = sys.argv[1:]
    fn = find_changelog(run_args)
    if not fn:
        sys.stderr.write("'ChangeLog' file not found!\n")
        sys.exit(1)
    else:
        versions = parse_versions(fn)
        if not versions:
            sys.stderr.write("No versions found in %s!\n" % (fn))
            sys.exit(1)
        else:
            sys.stdout.write(versions[0].strip())
            sys.exit(0)