#!/usr/bin/python3
"""
OpenLDAP tool to check CRC32 of LDIF files of slapd.d directory
"""

import argparse
import binascii
import logging
import os
import re
import sys

default_slapdd_path = '/etc/ldap/slapd.d'

### MAIN ####
parser = argparse.ArgumentParser()

parser.add_argument(
    '-d', '--debug',
    action='store_true',
    help='Show debug messages'
)

parser.add_argument(
    '-v', '--verbose',
    action='store_true',
    help='Show verbose messages'
)

parser.add_argument(
    '-l',
    '--log-file',
    action="store",
    type=str,
    dest="logfile",
    help="Log file path"
)

parser.add_argument(
    '-C', '--console',
    action='store_true',
    help='Also log on console (even if log file is provided)'
)

parser.add_argument(
    '-f', '--fix',
    action='store_true',
    help='Fix CRC32 value in LDIF files'
)

parser.add_argument(
    '-p', '--path',
    action='store',
    type=str,
    dest='slapdd_path',
    help='Default slapd.d directory path (default: %s)' % default_slapdd_path,
    default=default_slapdd_path
)


options = parser.parse_args()

# Initialize log
log = logging.getLogger()
logformat = logging.Formatter("%(asctime)s - " + os.path.basename(sys.argv[0]) + " - %(levelname)s - %(message)s")

if options.debug:
    log.setLevel(logging.DEBUG)
elif options.verbose:
    log.setLevel(logging.INFO)
else:
    log.setLevel(logging.WARNING)

if options.logfile:
    logfile = logging.FileHandler(options.logfile)
    logfile.setFormatter(logformat)
    log.addHandler(logfile)

if not options.logfile or options.console:
    logconsole = logging.StreamHandler()
    logconsole.setFormatter(logformat)
    log.addHandler(logconsole)

def check_file(dir_path, file_name):
    """
    Check CRC32 of an LDIF file

    :param  dir_path:   The directory path
    :param  file_name:  The file name
    """
    path = os.path.join(dir_path, file_name)

    lines = []
    current_crc32 = None
    try:
        with open(path, 'rb') as fd:
            for line in fd.readlines():
                if line.startswith(b'# AUTO-GENERATED FILE - DO NOT EDIT!! Use ldapmodify.'):
                    logging.debug('%s: AUTO-GENERATED line detected, pass (%s)', path, line)
                    continue
                if line.startswith(b'# CRC32 '):
                    logging.debug('%s: CRC32 line detected, retreive current CRC32 value (%s)', path, line)
                    current_crc32 = re.match('^# CRC32 (.*)$', line.decode()).group(1)
                    logging.debug('%s: current CRC32 found is "%s"', path, current_crc32)
                    continue
                lines.append(line)
    except IOError as err:
        logging.error('%s: fail to read file content (%s)', path, err)
        return False

    crc32 = ("%08X" % ((binascii.crc32(b"".join(lines)) & 0xFFFFFFFF) % (1<<32))).lower()
    if current_crc32:
        if current_crc32 == crc32:
            log.info('%s: current CRC32 value is correct (%s)', path, crc32)
        else:
            log.warning('%s: invalid CRC32 value found (%s != %s)', path, current_crc32, crc32)
            fix_crc32(path, crc32, lines)
    else:
        log.warning('%s: no CRC32 value found. Correct CRC32 value is "%s".', path, crc32)
        fix_crc32(path, crc32, lines)
    return True

def fix_crc32(path, crc32, lines):
    """
    Fix CRC32 value of an LDIF file

    :param  path:   The file path
    :param  crc32:  The CRC32 value of the file
    :param  lines:  Array of file lines without headers
    """
    if not options.fix:
        return True
    try:
        headers_lines = [
            b'# AUTO-GENERATED FILE - DO NOT EDIT!! Use ldapmodify.\n',
            b'# CRC32 ' + crc32.encode() + b'\n',
        ]
        with open(path, 'wb') as fd:
            for line in headers_lines + lines:
                fd.write(line)
    except IOError as err:
        logging.error('%s: fail to write new file content (%s)', path, err)
        return False
    return True

log.info('Checking CRC32 in slapd directory "%s"', options.slapdd_path)
for dirpath, dnames, fnames in os.walk(options.slapdd_path):
    log.debug('%s: sub-dirs = "%s", files = "%s"', dirpath, '", "'.join(dnames), '", "'.join(fnames))
    for fname in fnames:
        if fname.endswith('.ldif'):
            check_file(dirpath, fname)