#!/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

version = "0.0"
default_slapdd_path = "/etc/ldap/slapd.d"

# Main
parser = argparse.ArgumentParser(description=f"{__doc__} (version: {version})")

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=f"Default slapd.d directory path (default: {default_slapdd_path}",
    default=default_slapdd_path,
)


options = parser.parse_args()

# Initialize log
log = logging.getLogger()
logformat = logging.Formatter(
    f"%(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, retrieve 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 OSError as err:
        logging.error("%s: fail to read file content (%s)", path, err)
        return False

    # pylint: disable=consider-using-f-string
    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 OSError 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)