#!/usr/bin/env python

import optparse
import os.path
import sys

sys.path.insert(0, os.path.join(
        os.path.dirname(os.path.dirname(os.path.realpath(__file__))),
        'lib'))
import krb5
import roost

def macro_sub(s, sender):
    if s == '%me%':
        return sender
    return s

def parse_subsfile(path, sender):
    # Modelled after zwgc's parser.
    with open(path) as f:
        ret = []
        for line in f:
            idx = line.find('#')
            if idx >= 0:
                line = line[:idx]
            line = line.strip(' \n')
            # Skip blank lines.
            if not line:
                continue
            klass, inst, recip = line.split(',', 2)
            # Punt punts and unsubs.
            if klass and klass[0] in ('!', '-'):
                continue
            # Eh. Let's do all of them, like zwgc does.
            klass = macro_sub(klass, sender)
            inst = macro_sub(inst, sender)
            recip = macro_sub(recip, sender)
            # This is normally done in ZSubscribeTo, but roost won't
            # allow it:
            if recip and recip[0] == '*':
                recip = recip[1:]
            ret.append((klass, inst, recip))
        return ret

def zuser_is_personal(recip):
    return recip and recip[0] != '@'

def main(args):
    parser = optparse.OptionParser(
        usage='Usage: %prog [OPTIONS] [FILES]')
    parser.add_option('--server', default=roost.DEFAULT_SERVER,
                      help='Roost backend server (default: %default)')
    parser.add_option('--service', default=roost.DEFAULT_SERVICE,
                      help='Service name (default: %default)')
    (options, args) = parser.parse_args()

    # Get the default principal.
    ctx = krb5.Context()
    ccache = ctx.cc_default()
    principal = ccache.get_principal()
    principal_str = principal.unparse_name()

    # Parse out the subs files.
    args = args or [os.path.expanduser('~/.zephyr.subs')]
    all_subs = []
    for arg in args:
        all_subs.extend(parse_subsfile(arg, principal_str))

    good_subs = []
    for sub in all_subs:
        if zuser_is_personal(sub[2]) and sub[2] != principal_str:
            print 'Skipping <%s,%s,%s>; bad triple' % sub
        else:
            good_subs.append(sub)

    # Alway staple zephyr creds.
    zephyr = ctx.build_principal('ATHENA.MIT.EDU', ['zephyr', 'zephyr'])
    creds = ccache.get_credentials(principal, zephyr)

    # Confirm.
    print 'About to upload %d subscriptions to %s along with' % (len(good_subs),
                                                                 options.server)
    print 'a copy of your %s ticket.' % (zephyr.unparse_name(),)
    print
    print 'This will allow Roost to send and receive zephyrgrams on your behalf.'
    print
    print 'Press Enter to confirm, Ctrl-C to cancel.'
    raw_input()

    # Build the data.
    data = {
        'subscriptions': [{ 'class': s[0],
                            'instance': s[1],
                            'recipient': s[2] }
                          for s in good_subs],
        'credentials': creds.to_dict(),
    }

    # Get an auth token.
    token, _expires = roost.get_auth_token(options, principal_str,
                                           create_user=True)
    # And subscribe.
    roost.post(options, token, '/v1/subscribe', data)

    print 'Subscribed'

    return 0

if __name__ == '__main__':
    sys.exit(main(sys.argv[1:]))