#!/bin/sh

# Only count keys that satisfy this condition. $3 is the key index
# Use `xinput test "AT Translated Set 2 keyboard"` to find out key indices
CONDITION='($3 >= 24 && $3 <= 33) || ($3 >= 37 && $3 <= 54) || ($3 >= 52 && $3 <= 57)'

# cpm: characters per minute
# wpm: words per minute (1 word = 5 characters)
METRIC=wpm

FORMAT="  %d $METRIC\n"


case "$METRIC" in
	wpm) factor=3; ;;
	cpm) factor=1; ;;
	*) echo "Unsupported metric \"$METRIC\""; exit 1; ;;
esac

hackspeed_cache="$(mktemp -p '' hackspeed_cache.XXXXX)"
trap 'rm "$hackspeed_cache"' EXIT

# Write a dot to our cache for each key press
printf '' > "$hackspeed_cache"
xinput test "AT Translated Set 2 keyboard" | \
	stdbuf -o0 awk '$1 == "key" && $2 == "press" && ('"$CONDITION"') {printf "."}' >> "$hackspeed_cache" &

while true; do
	lines=$(stat --format %s "$hackspeed_cache")
	value=$(($lines * $factor / 5))

	printf '' > "$hackspeed_cache"
	printf "$FORMAT" "$value"

	sleep 20
done