#!/usr/bin/env bash
# 20260819 - Hyperling
# Alert the user every so often once the battery is low.

## Setup ##

echo "`date` - Checking Active Programs"

PID="$$"
ps -ef | grep battery_nag.sh | grep -v grep | grep -v killall | grep -v $$

active=`ps -ef | grep battery_nag.sh | grep -v grep | grep -v killall | grep -vc $$`
if (( "$active" >= 1 )); then
	echo "Program already running, exiting. Number of processes: $active"
	exit 1
fi

echo "`date` - Loading Functions"

which battery.function || {
	echo "ERROR: Battery function not found, exiting."
	exit 2
}
source battery.function

## Params ##

echo "`date` - Parsing Parameters"

typeset -i alert sleep

# Default to 20%.
alert=20
if [[ -n "$1" ]]; then
	echo -n "alert changed from '$alert' "
	alert="$1"
	echo "to '$alert'"
fi

# Default to 5 minutes.
sleep=300
if [[ -n "$2" ]]; then
	echo -n "sleep changed from '$sleep' "
	sleep="$2"
	echo "to '$sleep'"
fi

# Default to true.
accelerate="Y"
if [[ -n "$3" ]]; then
	echo -n "accelerate changed from '$accelerate' "
	accelerate="$3"
	echo "to '$accelerate'"
fi

echo "Alerting when under ${alert}%."
echo "Notifying every ${sleep} seconds."
if [[ "$accelerate" == "Y" ]]; then
	echo -n "Speeding up notifications as % gets lower."
else
	echo -n "Notifcations staying persistent."
fi
echo " (accelerate == $accelerate)"

## Main ##

echo "`date` - Starting Loop"

while true; do

	batt=`battery-display`
	batt=${batt//%/}

	if (( batt <= alert )); then
		title="Battery is below ${alert}%"
		message="Currently at ${batt}%"
		cmd="`which fyi 2>/dev/null || which notify-send 2>/dev/null`"
		if [[ -z "$cmd" ]]; then
			echo "ERROR: No command found to send notification, exiting."
			echo "Please install 'fyi' or 'notify-send' to use this script."
			echo "If not using a DE, also ensure 'dunst' or similar is running."
			exit 3
		fi

		$cmd "$title" "$message"
		status="$?"

		if [[ "$status" == 0 ]]; then
			echo -n "`date` - Success! "
		else
			echo -n "`date` - ERROR: "
		fi
		echo "Nag returned status ${status}."
	else
		echo "`date` - Battery at ${batt}%, did not nag."
	fi

	time=$sleep
	if [[ "$accelerate" == "Y" ]]; then
		if (( batt > 0 )); then
			time=$(( time / (alert / batt) ))
		else
			time=10
		fi
	fi
	# Showing a notification every 10 seconds makes it persistent.
	# Any more than that casues multiple to stack which is unnecessary.
	if (( time < 10 )); then
		time=10
	fi
	echo "`date` - Sleeping for ${time}."
	sleep $time
done