#!/bin/sh

JATWIS_MODE=""
JATWIS_LOCKFILE=""
JATWIS_TIMEOUT=10000
JATWIS_FREQUENCY=600
JATWIS_FIRST_RUN=1

JATWIS_SCRIPT_LOCATION=""
JATWIS_URL=""

function poll_default() {
	echo "error: no poll handler for \"$JATWIS_MODE\", exiting..."
	exit 1
}
JATWIS_POLL_FN=poll_default

function usage() {
	cat << EOF
Usage: jatwisd [options]

	--help
		display (this) help message

	-h, --https <https url>
		poll url using https

	-s, --sftp <sftp url>
		poll url using sftp

	-e, --exec <path>
		script to run if the url is reachable

	-t, --timeout <milliseconds>
		timeout period (in milliseconds)
		default: 10 seconds (10000)

	-f, --freq, --frequency <seconds>
		polling frequency (in seconds)
		default: every 10 minutes (600)

	-l, --lockfile <path>
		set lockfile location and enable lockfile checking
	
	-p, --no-protection
		disable protection agains endpoint success on first run

See jatwisd(1) for more info
EOF
}

function check_ready() {
	if [ -z "$JATWIS_URL" ]; then
		echo "error: no endpoint to poll, exiting..."
		exit 1
	elif [ -z "$JATWIS_SCRIPT_LOCATION" ]; then
		echo "error: no script or executable specified, exiting..."
		exit 1
	fi

	if [ ! -f "$JATWIS_SCRIPT_LOCATION" ]; then
		if [ ! -x "$JATWIS_SCRIPT_LOCATION" ]; then
			echo "error: script or executable not executable, exiting..."
			exit 1
		fi
		echo "error: script or executable not found, exiting..."
		exit 1
	fi

	if [ "$JATWIS_MODE" == "HTTPS" ] && [[ "$JATWIS_URL" != https://* ]]; then
		echo "error: https url without https:// protocol, exiting..."
		exit 1
	fi
}

function trigger() {
	if [ $JATWIS_FIRST_RUN -eq 1 ]; then
		echo "error: poll succeeded on first run, exiting..."
		exit 1
	fi

	sh "$JATWIS_SCRIPT_LOCATION"
}

function poll_https() {
	curl -s -o /dev/null -w "%{http_code}" "$JATWIS_URL"
	trigger
}

# parse args
while [ "$1" != "" ]; do
	case $1 in
		--help)
			usage
			exit
			;;
		-h|--https)
			JATWIS_URL="$2"
			JATWIS_MODE="HTTPS"
			JATWIS_POLL_FN=poll_https
			shift
			;;
		-s|--sftp)
			JATWIS_URL="$2"
			JATWIS_MODE="SFTP"
			shift
			;;
		-e|--exec)
			JATWIS_SCRIPT_LOCATION="$2"
			shift
			;;
		-t|--timeout)
			JATWIS_TIMEOUT="$2"
			shift
			;;
		-f|--freq|--frequency)
			JATWIS_FREQUENCY="$2"
			shift
			;;
		-l|--lockfile)
			JATWIS_LOCKFILE="$2"
			shift
			;;
		-p|--no-protection)
			JATWIS_FIRST_RUN=0
			;;
		*)
			echo "unknown parameter \"$PARAM\""
			usage
			exit 1
			;;
	esac
	shift
done

check_ready

while :; do
	$JATWIS_POLL_FN

	JATWIS_FIRST_RUN=0
	sleep "$JATWIS_FREQUENCY"
done