dot_testing/lappy/builds/utils/status

#!/bin/bash

# try to load the sleep builtin dynamically, because otherwise there's
# a *lot* of overhead (in terms of PID count)
if [[ $(</proc/cmdline) = *"nixos-system"* ]]; then
	enable -f /run/current-system/sw/lib/bash/sleep sleep
else
	enable -f /lib/bash/sleep sleep
fi

schedule_needs_update="yes"

get_schedule_info () {
	if [ "$schedule_needs_update" = "yes" ]; then
		output=$(
			khal at now --format '{title}|{end-time}|{categories}' | \
				awk -F'|' '{if($3 == "school") { print $1 "|" $2 }}'
		)

		if [ -z "$output" ]; then
			schedule_needs_update="no"
			schedule_status=""
			return
		fi

		class_name=${output%%|*}
		schedule_time=${output##*|}
		schedule_time_hours=${schedule_time%%:*}
		schedule_time_minutes=${schedule_time##*:}
		schedule_time_unix=$(date --date "$schedule_time" "+%s")

		schedule_needs_update="no"
	fi

	printf -v current_time '%(%s)T' -1
	difference=$(($schedule_time_unix - $current_time))
	if [ "$difference" -lt 0 ]; then
		schedule_needs_update="yes"
		get_schedule_info
	fi
	until_end=$(($difference / 60))

	if [ "$until_end" -le 5 ]; then
		until_end_seconds=$(($difference % 60))
		schedule_status=$(printf "%02d:%02d left in %s/" "$until_end" "$until_end_seconds" "$class_name")
	else
		schedule_status=$(printf "%d minutes left in %s/" "$until_end" "$class_name")
	fi
}

get_cmus_info () {
	if [ /dev/shm/status/cmus -nt /dev/shm/status/modified ]; then
		cmus_status="$(</dev/shm/status/cmus)/"
		touch /dev/shm/status/modified
	fi
}

get_battery_info () {
	battery_status=$(</sys/class/power_supply/BAT0/capacity)
}

get_time_info () {
	printf -v date_status '%(%d(%a)-%m(%b)-%y)T %(%H)T:%(%M)T:%(%S)T/' -1
}

while true; do
	# use /dev/shm to minimize the amount of i/o on disk
	if [ ! -d /dev/shm/status ]; then
		mkdir -p /dev/shm/status
		touch /dev/shm/status/modified
	fi

	get_time_info
	get_battery_info
	get_cmus_info
	get_schedule_info

	printf "%s%s%s%s\n" "$schedule_status" "$cmus_status" "$date_status" "$battery_status"
	sleep 1
done | dwm-setstatus