#!/usr/bin/env python

import argparse
from datetime import datetime
import fnmatch
import os
import prettytable
import yaml

from OpenSSL import crypto


def find_hiera_files(dir):
    hiera_files = []
    for root, _, filenames in os.walk(dir):
        files = (fnmatch.filter(filenames, '*.yaml') +
                 fnmatch.filter(filenames, '*.yml'))
        hiera_files.extend([os.path.join(root, f) for f in files])
    return hiera_files


def find_certificates(k, v, hiera_dir, filename):
    certificates = []
    if isinstance(v, str) and v.startswith('-----BEGIN CERTIFICATE-----'):
        fn = os.path.relpath(filename, hiera_dir)
        c = get_x509_commonname_and_notafter(v)
        certificates.append({'filename': fn,
                             'key': k,
                             'name': c[0],
                             'expire_at': c[1]})
    elif isinstance(v, dict):
        for k2, v2 in v.iteritems():
            if k is not None:
                k2 = "%s['%s']" % (k, k2)
            certificates.extend(find_certificates(k2, v2, hiera_dir, filename))
    elif isinstance(v, list):
        for k2, v2 in enumerate(v):
            if k is not None:
                k2 = "%s[%s]" % (k, k2)
            certificates.extend(find_certificates(k2, v2, hiera_dir, filename))
    return certificates


def get_x509_commonname_and_notafter(cert):
    cert = crypto.load_certificate(crypto.FILETYPE_PEM, cert)
    common_name = str(cert.get_subject().commonName)
    not_after = datetime.strptime(cert.get_notAfter(), '%Y%m%d%H%M%SZ')
    return (common_name, not_after)


def main():

    parser = argparse.ArgumentParser()
    parser.add_argument('hiera_dir')
    args = parser.parse_args()
    hiera_dir = args.hiera_dir

    certificates = []
    filenames = find_hiera_files(hiera_dir)
    for filename in filenames:
        with open(filename, 'r') as fh:
            data = yaml.load(fh) or {}
            certs = find_certificates(None, data, hiera_dir, filename)
            certificates.extend(certs)

    fields = ['Filename', 'Key', 'Name', 'Expire at']
    pt = prettytable.PrettyTable(fields, caching=False)
    pt.align = 'l'
    for cert in certificates:
        pt.add_row((cert['filename'], cert['key'],
                    cert['name'], cert['expire_at']))
    print pt.get_string(sortby='Expire at')


if __name__ == '__main__':
    main()