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

SLEEPTIME=60
PLOTDIR=""

function usage() {
	echo >&2 "Usage: $0 [-s sleeptime] [-o plotdir]"
	echo >&2 "  -s sleeptime   Time to sleep between polls; default $SLEEPTIME seconds"
	echo >&2 "  -o plotdir     Output directory for plots; default none"
}

ARGS=$(getopt -o 'hs:o:' -n "$0" -- "$@")
eval set -- "$ARGS"
unset ARGS

while true; do
	case "$1" in
		-h)
			usage
			exit 0
			;;

		-s)
			SLEEPTIME="$2"
			shift 2
			;;

		-o)
			PLOTDIR="$2"
			shift 2
			;;

		--)
			shift
			break
			;;
	esac
done

if [[ $# -gt 0 ]]; then
	usage
	exit 1
fi

[[ -n $PLOTDIR ]] && PLOTDIR=$(realpath "$PLOTDIR")
[[ ! -d $PLOTDIR ]] && { echo >&2 "'$PLOTDIR' is not a directory"; exit 1; }

cd "$(dirname "$0")"

stat --version 2>/dev/null | grep -q 'GNU coreutils' || {
	echo >&2 "Not gnu stat!"; exit 1;
}

logf_dbsize="log_dbsize.txt"
[[ -f $logf_dbsize ]] && echo "Appending to '$logf_dbsize'" || echo "Logging to '$logf_dbsize'"

while true; do
	now="$EPOCHSECONDS"
	dbsize=$(stat -c '%s' ../db.db)
	echo "$now $dbsize" >>"$logf_dbsize"

	if [[ -n $PLOTDIR ]]; then
		gnuplot <<EOF
set terminal png size 960,640
set output '$PLOTDIR/dbsize.png'
set grid
plot '$logf_dbsize' u (\$1/3600/24):2 w lp
EOF
	fi

	sleep "$SLEEPTIME"
done