#!/usr/local/bin/bash
set -euo pipefail

readonly DHCPD_CONF_FILE='/etc/dhcpd.conf'
readonly DHCPD_LEASES_FILE='/var/db/dhcpd.leases'
readonly UNBOUND_LOCAL_DATA_FILE='/var/unbound/etc/local-data-dhcpd.conf'
UNBOUND_LOCAL_DATA_FILE_TMP="$(mktemp)"
readonly UNBOUND_LOCAL_DATA_FILE_TMP

get_file_modify_time() {
	stat -f %m "$1"
}

if [ -e "$UNBOUND_LOCAL_DATA_FILE" ]; then
	UNBOUND_LOCAL_DATA_FILE_MODIFY_TIME="$(get_file_modify_time "$UNBOUND_LOCAL_DATA_FILE")"

	if [ "$UNBOUND_LOCAL_DATA_FILE_MODIFY_TIME" -gt "$(get_file_modify_time "$DHCPD_CONF_FILE")" ]; then
		if [ "$UNBOUND_LOCAL_DATA_FILE_MODIFY_TIME" -gt "$(get_file_modify_time "$DHCPD_LEASES_FILE")" ]; then
			exit 0
		fi
	fi
fi

../dhcpd/list_active_assignments | ../unbound/local-data-file-generator > "$UNBOUND_LOCAL_DATA_FILE_TMP"

mv "$UNBOUND_LOCAL_DATA_FILE_TMP" "$UNBOUND_LOCAL_DATA_FILE"
chmod 644 "$UNBOUND_LOCAL_DATA_FILE"

rcctl reload unbound