Invoke notify-send based on khal, with a 15 and 3 minute wakeup margin - should play nice with all kinds of UTF-8 and special characters (Curse you, colleagues who put paths to windows shares into appointments. \\foo\)

remind-khal-notify-send

#!/usr/bin/env bash

set -euo pipefail
trap 'echo "ERROR: $BASH_SOURCE:$LINENO $BASH_COMMAND" >&2' ERR

for prg in notify-send khal; do
	if ! which $prg &>/dev/null; then
		echo $prg not found
		exit -1
	fi
done

function clean_iconv {
	iconv -c -t UTF-8
}

function clean_grep {
	grep -axv '.*'
}
if which iconv &>/dev/null; then
	clean=clean_iconv
else
	clean=clean_grep
fi

#set -x
lastturn=$(date +%s -d"now - 120 minutes")
while true; do
	turn=$(( $(date +%s) / 60 * 60 ))
	khal list -f $'{start}\3{title}\3{description}\3\4' -df '' today \
	| while IFS= read -rd $'\4' e; do
		begin=$(date -d"$(cut <<<"$e" -z -d$'\3' -f1 | tr -d \\0)" +%s)
		title="$(cut <<<"$e" -z -d$'\3' -f2 | tr -d \\0)"
		desc="$(cut <<<"$e" -z -d$'\3' -f3 | tr -d \\0 | cut -c-50)"
		notify=false
		for n in 3 15; do
			if test $lastturn -lt $(( $begin - 60 * $n )) && test $(( $begin - 60 * $n )) -le $turn; then
				in=$(( ($begin - $(date +%s)) / 60 ))
				prio=low
				if test $in -lt 5; then
					prio=critical
				elif test $in -lt 16; then
					prio=normal
				fi
				if test $in -gt 0; then
					in="In $in min."
				else
					in="$(( - $in )) min. ago"
				fi
				echo "Reminding of $title ($in)"
				notify-send -u $prio -- "$in: $($clean <<<"$title")" "$($clean <<<"$desc")" || echo notify-send failed
				break
			fi
		done
	done
	lastturn=$turn
	snooze=$(( $turn + 60 - $(date +%s) ))
	if test $snooze -gt 0; then
		sleep $snooze
	fi
done