#!/bin/bash

readonly DB_PATH="/var/lib/knot-resolver/leases.db"

main() {
	# Create the database if it does not exist
	if [ ! -f "${DB_PATH}" ]; then
		if ! sqlite3 "${DB_PATH}" >/dev/null \
				</usr/lib/knot-resolver/leases.schema; then
			echo "${0}: Failed to create database" >&2
			return 1
		fi
	fi

	local action="${1}"
	shift

	case "${action}" in
		commit)
			local address
			local hostname
			local domainname

			while [ $# -gt 0 ]; do
				case "${1}" in
					ADDRESS=*)
						address="${1#*=}"
						;;
					HOSTNAME=*)
						hostname="${1#*=}"
						;;
					DOMAINNAME=*)
						domainname="${1#*=}"
						;;
					*)
						# Ignore any unknown arguments
						;;
				esac
				shift
			done

			# Check if we have enough data
			if [ -z "${address}" ]; then
				echo "${0}: Missing ADDRESS=" >&2
				return 2
			elif [ -z "${hostname}" ]; then
				echo "${0}: Missing HOSTNAME=" >&2
				return 2
			elif [ -z "${domainname}" ]; then
				echo "${0}: Missing DOMAINNAME=" >&2
				return 2

			# Validate the hostname
			elif ! [[ ${hostname} =~ ^[A-Za-z0-9_-]{1,63}$ ]]; then
				echo "${0}: Invalid hostname" >&2
				return 2
			fi

			# Join the hostname together
			hostname="${hostname}.${domainname}."

			# Make the hostname lowercase
			hostname="${hostname,,}"

			sqlite3 "${DB_PATH}" <<-EOF
				-- Set parameters
				.parameter set :address '${address}'
				.parameter set :hostname '${hostname}'

				-- Run statement
				INSERT INTO
					leases
				(
					address,
					hostname
				)
				VALUES
				(
					:address,
					:hostname
				)
				ON CONFLICT
				(
					address
				)
				DO UPDATE SET
					hostname = excluded.hostname;
			EOF
			;;

		release|expiry)
			local address

			while [ $# -gt 0 ]; do
				case "${1}" in
					ADDRESS=*)
						address="${1#*=}"
						;;
					*)
						# Ignore any unknown arguments
						;;
				esac
				shift
			done

			# Check if we have enough data
			if [ -z "${address}" ]; then
				echo "${0}: Missing ADDRESS=" >&2
				return 2
			fi

			sqlite3 "${DB_PATH}" <<-EOF
				-- Set parameters
				.parameter set :address '${address}'

				-- Run statement
				DELETE FROM
					leases
				WHERE
					address = :address;
			EOF
	esac

	return 0
}

main "$@" || exit $?