'''
Audit changes to Perforce groups.

This should be used as a form-save trigger:

  audit-groups form-save group "python3 audit_groups.py -p perforce:1666 -u P4USER -g supergroup -L /p4/audit.groups -S smtp.example.org -e p4admins@example.org -a p4admins@example.org %formname% %formfile% %user%"

$Author: lester_cheung $
$Id: //guest/lester_cheung/p4util/p4util/trigger/form/audit_groups.py#2 $
'''

__version__ = '0.{0}'.format('$Change: 10926 $'.split()[-2])

import logging
import argparse
import difflib
import shlex
import os.path
import sys
import functools
from email.mime.text import MIMEText
import smtplib

from pprint import pprint, pformat


# try:
#     from ...p4cli import P4
# except:
#     # failback to P4Python (so we can run the script without installing the module)
#     import P4

from ...p4cli import P4CLI as P4 # We are using P4CLI.run_plaintext which is not in P4Python

def parse_args():
    ap = argparse.ArgumentParser(description=__doc__)
    p4 = P4()
    ap.add_argument('-p', '--port', metavar=p4.env('P4PORT'), default=p4.env('P4PORT'))
    ap.add_argument('-u', '--user', metavar=p4.env('P4USER'), default=p4.env('P4USER'))
    ap.add_argument('-c', '--client', metavar=p4.env('P4CLIENT'), default=p4.env('P4CLIENT'))
    ap.add_argument('-C', '--charset', metavar=p4.env('P4CHARSET'), default=p4.env('P4CHARSET'))

    ap.add_argument('-g', '--group', action='append', dest='groups',
                    help='Group to audit. Repeat this options to specify more than one group.')
    ap.add_argument('-L', '--log', default='audit.group')
    ap.add_argument('-S', '--smtp-server', help='e.g. smtp.example.org:25')
    ap.add_argument('-e', '--email', action='append', dest='emails',
                    help='Change notifications will be sent to this email. '
                    'Repeat this option to add multiple recipients')
    ap.add_argument('-a', '--admin-email', default='p4admin@example.org', metavar='p4admin@example.org')

    ap.add_argument('formname', metavar='%formname%')
    ap.add_argument('formfile', metavar='%formfile%')
    ap.add_argument('user', metavar='%user%')

    return ap.parse_args()

def sendemail(cfg, msg):
    mail = MIMEText(msg)
    mail['From'] = cfg.admin_email
    mail['To']   = ', '.join(cfg.emails)
    mail['Subject'] = '[Perforce audit] Group "{0}" updated by {1}'.format(cfg.formname, cfg.user)
    print(mail.as_string())
    smtp = smtplib.SMTP( *(cfg.smtp_server.split(':')) )
    smtp.sendmail(from_addr=cfg.admin_email, to_addrs=cfg.emails, msg=mail.as_string())

def main():

    if cfg.groups and cfg.formname not in cfg.groups:
        sys.exit(0)             # short-circuit and exit early

    p4 = P4()
    p4.prog = __file__

    if cfg.user:
        p4.user = cfg.user
    if cfg.port:
        p4.port = cfg.port
    if cfg.client:
        p4.client = cfg.client
    if cfg.charset:
        if cfg.charset == 'none':
            p4.charset = None
        else:
            p4.charset = cfg.charset

    p4.connect()

    grp0 = p4.run_plaintext( *shlex.split('group -o {0}'.format(cfg.formname)) ).splitlines()
    p4.disconnect()

    with open(cfg.formfile) as fd:
        grp1 = fd.read().splitlines()

    differ = difflib.Differ()
    diff = list(differ.compare(grp0, grp1))

    if not functools.reduce(lambda x, y: x or y,
                            [ x[0] in '-+?' for x in
                              filter(lambda x: not '', diff) ] ):
        # Exit if there is no diff markers in front of all lines
        sys.exit(0)

    msg = 'Group {0} updated by {1}:\n'.format(cfg.formname, cfg.user) + '\n'.join(diff)
    log.info(msg)

    if cfg.emails:
        try:
            sendemail(cfg, '\n'.join(diff))
        except Exception as e:
            import io, traceback
            sbuf = io.StringIO()
            traceback.print_exc(file=sbuf)
            log.error('Error sending notification email.' + sbuf.getvalue())



if __name__ == '__main__':
    cfg = parse_args()

    logging.basicConfig(format='%(asctime)-15s %(funcName)s.%(levelname)s %(message)s',
                        filename=cfg.log,
                        level=logging.DEBUG)
    log = logging.getLogger(__name__)
    log.debug(cfg)

    main()
    # making sure that we exit with zero return so the group mod
    # gets committed
    sys.exit(0)