#!/usr/bin/env bash

file="$1"

horizontal=0
depth=0

while read line; do
	direction="$(echo "$line" | cut -d ' ' -f 1)"
	amount="$(echo "$line" | cut -d ' ' -f 2)"
	case "$direction" in
		forward) horizontal=$((horizontal + amount)) ;;
		down) depth="$((depth + amount))" ;;
		up) depth="$((depth - amount))" ;;
	esac
done < <(cat "$file")

echo "Horizontal: $horizontal"
echo "Depth: $depth"
echo "Product: $(( depth * horizontal ))"