#!/opt/imh-python/bin/python3
"""Setup SpamAssassin on CWP.
Configuration and postfix integration provided by Dakota P."""
import re
from pathlib import Path
from datetime import datetime
from subprocess import run

SA_ENV = """# Options to spamd
SAHOME="/var/lib/spamassassin/"
SPAMDOPTIONS="-c -m4 -H --username nobody -s"
"""

SA_RULES = """rewrite_header Subject [***SPAM***]
required_hits 5.0
required_score 5.0
report_safe 0
use_bayes 1
bayes_ignore_header X-Bogosity
bayes_ignore_header X-Spam-Flag
bayes_ignore_header X-Spam-Status
"""


def rename_replace(path, content):
    rename_tstamp = datetime.now().strftime("%Y%m%d_%H%M")
    path.rename(f"{path}-{rename_tstamp}")
    with open(path, "w", encoding="utf-8") as new_file:
        new_file.write(content)


def restart_service(service):
    ret_code = run(["systemctl", "restart", f"{service}"], check=True)
    if ret_code.returncode != 0:
        return f"{service} did not restart, check systemctl status output"
    return None


def configure_spamassassin():
    """Setup SpamAssassin"""
    env_path = Path("/etc/sysconfig/spamassassin")
    filter_path = Path("/etc/mail/spamassassin/local.cf")
    service_path = Path("/usr/lib/systemd/system/spamassassin.service")

    for f_path in env_path, filter_path, service_path:
        if not f_path.exists():
            raise FileNotFoundError(
                f"Error! Missing or inaccessible path: {f_path} Bailing."
            )

    try:
        rename_replace(env_path, SA_ENV)
        rename_replace(filter_path, SA_RULES)
        srv_new = re.sub(
            r"(\$SPAMDOPTIONS)\n",
            r"\1 ${SAHOME}spamd.log\nStartLimitBurst=0\n",
            service_path.read_text(encoding="utf-8"),
        )
        rename_replace(service_path, srv_new)
    except:
        raise

    print("Reloading systemd daemon")
    if run(["systemctl", "daemon-reload"], check=True).returncode != 0:
        print("Non-Zero exit code returned from systemctl daemon-reload")
    restart_service("spamassassin")


def configure_postfix():
    """Setup Postfix"""
    post_path = Path("/etc/postfix/master.cf")

    if not post_path.exists():
        raise FileNotFoundError(
            f"Error! Missing or inaccessible path: {post_path} Bailing."
        )

    try:
        post_new = re.sub(
            '(receive_override_options=no_address_mappings\n)(#\n##)',
            r'\1  -o content_filter=spamassassin\n\2',
            post_path.read_text(encoding="utf-8"),
        )
        post_fnl = re.sub(
            '(/usr/libexec/postfix/policyd-spf\n)',
            r'\1# SA enable\nspamassassin      unix  -       n       n       -       -       pipe\n  user=nobody argv=/usr/bin/spamc -f -e\n  /usr/sbin/sendmail -oi -f ${sender} ${recipient}\n',
            post_new,
        )
        rename_replace(post_path, post_fnl)
    except:
        raise
    restart_service("postfix")


if __name__ == "__main__":
    try:
        configure_spamassassin()
        configure_postfix()
        print("SpamAssassin setup complete!")
    except Exception as e:
        exit(f"SpamAssassin setup failed with exception!\n{e}")