#!/bin/sh

# Usage:
#	price <currency-base currency> <name of currency> <icon> <signal>
#	price bat-btc "Basic Attention Token" 🦁 24
#	This will give the price of BAT denominated in BTC and will update on
#	signal 24.
# When the name of the currency is multi-word, put it in quotes.

[ -z "$1" ] && exit 1

url="${CRYPTOURL:-rate.sx}"
target="${1%%-*}"
denom="${1##*-}"
name="${2:-$1}"
icon="${3:-💰}"
case "$denom" in
	"$target"|usd) denom="usd"; symb="$" ;;
	gbp) symb="£" ;;
	eur) symb="€" ;;
	btc) symb="" ;;
esac
interval="@14d"	# History contained in chart preceded by '@' (7d = 7 days)
dir="${XDG_CACHE_HOME:-$HOME/.cache}/crypto-prices"
pricefile="$dir/$target-$denom"
chartfile="$dir/$target-$denom-chart"

[ -d "$dir" ] || mkdir -p "$dir"

checkprice() {
	[ "$(stat -c %y "$pricefile" 2>/dev/null |
		cut -d' ' -f1)" = "$(date '+%Y-%m-%d')" ]
}

updateprice() { { grep -q -m1 '^up$' /sys/class/net/w*/operstate || grep -q -m1 '^up$' /sys/class/net/e*/operstate; } &&
	curl -sf \
		--fail-early "${denom}.${url}/1${target}" "${denom}.${url}/${target}${interval}" \
		--output "$pricefile" --output "$chartfile" &&
		touch "$pricefile" "$chartfile"
}

checkprice || updateme="1"

case $BLOCK_BUTTON in
	1) setsid "$TERMINAL" -e less -Srf "$chartfile" ;;
	2) notify-send -u low "$icon Updating..." "Updating $name price..." ; updateme="1" ; showupdate="1" ;;
	3) uptime="$(date -d "$(stat -c %x "$pricefile" 2>/dev/null)" '+%D at %T' | sed "s|$(date '+%D')|Today|")"
		notify-send "$icon $name module" "\- <b>Exact price: \$$(cat "$pricefile")</b>
- Left click for chart of changes.
- Middle click to update.
- Shows 🔃 if updating prices.
- <b>Last updated:
	$uptime</b>" ;;
	6) setsid -f "$TERMINAL" -e "$EDITOR" "$0" ;;
esac

[ -n "$updateme" ] &&
	if [ -n "$showupdate" ]; then
		updateprice && notify-send "$icon Update complete." "$name price is now \$$(cat "$pricefile")"
	else
		# shellcheck disable=SC2015
		[ -n "$4" ] &&
			( flock -n 9 &&
				( tries=0; while [ $tries -ne 100 ]; do
					updateprice && break ||
						{ tries=$((tries+1)); sleep .1; }
				done
				! checkprice &&
					until updateprice; do sleep 60; done
				pkill -RTMIN+"$4" "${STATUSBAR:-dwmblocks}"
				) &
			echo; exit ) 9>"${XDG_RUNTIME_DIR}/sb-price.lock" ||
				updateprice
	fi

[ -f "$pricefile" ] && printf "%s%s%0.2f" "$icon" "$symb" "$(cat "$pricefile")"