#!/bin/sh

# Manage events (replacement for https://git.tronto.net/sdep)

# Usage: event [command [argument]]
# See usage() for details

file="$HOME/box/events" # Change to $XDG_DATA_HOME/events or whatever
editor=${EDITOR:-vi}
notify=${NOTIFY:-"notify push"}

usage() {
	echo "Usage: event [command]"
	echo "Commands:"
	echo "  add [day]    Add a new event (default date: none)"
	echo "               day: today, t; tomorrow, tm"
	echo "  clear        Sort and cleanup event file"
	echo "  edit         Open event file in $editor"
	echo "  list [date]  List all events on date (default: all events)"
	echo "               date: now, n; today, t; tomorrow, tm;"
	echo "                     week, w; nextweek, nw;"
	echo "                     future, f; past, p"
	echo "  notify-loop  Notify of all past events, then start a loop that"
	echo "               checks for events every minute and notifies"
}

secondstoday() {
	if [ "$(uname)" = "Linux" ]; then
		date -d @$1 +'%Y-%m-%d'
	else # Assume BSD date
		date -r $1 +'%Y-%m-%d'
	fi
}

secondstomin() {
	if [ "$(uname)" = "Linux" ]; then
		date -d @$1 +'%Y-%m-%d %H:%M'
	else # Assume BSD date
		date -r $1 +'%Y-%m-%d %H:%M'
	fi
}

datetoseconds() {
	# Read date in YYYY-MM-DD HH:MM format
	if [ "$(uname)" = "Linux" ]; then
		date -d "$1 $2" +'%s'
	else # Assume BSD date
		date -f '%Y-%m-%d %H:%M' -j "$1 $2" +'%s'
	fi
}

today() { echo "$(date +'%Y-%m-%d') 00:00"; }
dayplus() {
	d="$1"
	n="$(datetoseconds $(today))"
	echo "$((n+d*60*60*24))"
}
monday() { d="$(date +%u)"; dayplus "$((1-d))"; }
monday1() { d="$(date +%u)"; dayplus "$((8-d))"; }
monday2() { d="$(date +%u)"; dayplus "$((15-d))"; }
daydiff() {
	ar="$1"
	d="$(date +%u)"
	case "$ar" in
		mon|monday)
			w=1
			;;
		tue|tuesday)
			w=2
			;;
		wed|wednesday)
			w=3
			;;
		thu|thursday)
			w=4
			;;
		fri|friday)
			w=5
			;;
		sat|saturday)
			w=6
			;;
		sun|sunday)
			w=7
			;;
		*)
			w=0
			;;
	esac
	[ "$w" = "0" ] && echo "" || echo "$(((w-d+7) % 7))"
}

secondsline() {
	# TODO: this function is not needed, need similar one with weekday
	line="$(cat)"
	s="$(datetoseconds $line)"
	t="$(echo "$line" | sed -E 's/....-..-.. .{1,2}:.. //g')"
	echo "$s $t"
}

filterlines() {
	while read -r line; do
		cleanline="$(echo "$line" | awk '{print $1, $2}')"
		s="$(datetoseconds $cleanline)"
		[ "$s" -ge "$1" ] && [ "$s" -lt "$2" ] && echo "$line"
	done
}

list() {
	if [ -z "$1" ]; then
		cat
	elif [ "$1" = "now" ] || [ "$1" = "n" ]; then
		grep "$(date +'%Y-%m-%d %H:%M')"
	elif [ "$1" = "today" ] || [ "$1" = "t" ]; then
		grep "$(date +'%Y-%m-%d')"
	elif [ "$1" = "tomorrow" ] || [ "$1" = "tm" ]; then
		grep "$(secondstoday $(dayplus 1))"
	elif [ "$1" = "week" ] || [ "$1" = "w" ]; then
		filterlines "$(monday)" "$(monday1)"
	elif [ "$1" = "nextweek" ] || [ "$1" = "nw" ]; then
		filterlines "$(monday1)" "$(monday2)"
	elif [ "$1" = "future" ] || [ "$1" = "f" ]; then
		filterlines "$(date +%s)" "9999999999"
	elif [ "$1" = "past" ] || [ "$1" = "p" ]; then
		filterlines "0" "$(date +%s)"
	fi
}

case "$1" in
	add)
		if [ "$2" = "today" ] || [ "$2" = "t" ]; then
			d="$(date +'%Y-%m-%d')"
		elif [ "$2" = "tomorrow" ] || [ "$2" = "tm" ]; then
			d="$(secondstoday $(dayplus 1))"
		elif [ -n "$2" ]; then
			d="$(secondstoday $(dayplus $(daydiff $2)))"
		fi
		[ -n "$d" ] && printf '%s ' "$d"
		read -r line
		[ -n "$d" ] && line="$d $line"
		echo "$line" >> "$file"
		;;
	clear)
		tmp=$(mktemp)
		cat "$file" | list future | sort > "$tmp"
		mv "$tmp" "$file"
		;;
	edit)
		"$editor" "$file"
		;;
	list)
		cat "$file" | list $2 | sort
		;;
	notify-loop)
		clean="sed -E 's/....-..-.. .{1,2}:..[[:space:]]*//g'"
		cat "$file" | list past | sort | \
		    sed -E 's/....-..-.. .{1,2}:..[[:space:]]*//g' | \
			while read text; do
				$notify "$text"
			done &
		while true; do
			cat "$file" | list now | sort | \
			    sed -E 's/....-..-.. .{1,2}:..[[:space:]]*//g' | \
				while read text; do
					$notify "$text"
				done &
			sleep $((60 - $(date +%-S)))
		done
		;;
	*)
		usage
		;;
esac