#!/bin/bash

set -e
[ -n "$DEBUG" ] && set -x

print_gateway_uri=
print_time_diff=
print_json=
if=wlan0
debug=
while getopts djuhDI: opt; do
	case "$opt" in
	d) print_time_diff=1 ;;
	j) print_json=1 ;;
	u) print_gateway_uri=1 ;;
	I) if=$OPTARG ;;
	D) debug=1 ;;
	h | ?)
		printf "usage: hspl [options]\n"
		printf "\n"
		printf "supported hotspot vendors:\n"
		printf "    hotsplots.de (e.g. Espresso House / public libraries)\n"
		printf "    pbspot (e.g. CoffeeFellows)\n"
		printf "\n"
		printf "options:\n"
		printf "  -d   print time until expiry in seconds\n"
		printf "  -j   output json\n"
		printf "  -u   print gateway address\n"
		printf "  -I   use a specific interface (default: %s)\n" "$if"
		printf "  -D   emit the html for debugging\n"
		printf "\n"
		exit 2
		;;
	esac
done
shift $((OPTIND - 1))

gateway=$(ip route show dev "$if" | awk '/default via/{print $3; exit}')

if [ -n "$print_gateway_uri" ]; then
	echo "$gateway"
	exit 0
fi

html=$(curl -Ls --interface "$if" "$gateway")

t=
tx=
rx=
logged_in=0
vendor=unknown
name=unknown

if [ -n "$debug" ]; then
	echo "$html"
	exit 1
fi

# hotspot vendor implementations go here:

if grep -q pbspot <<<"$html"; then
	vendor=pbspot
	# TODO: logged_in=$(grep -qi 'eingeloggt seit' && echo 1)
	t=$(grep -i 'expires' <<<"$html" | awk -F 'td>' '{print $4}' | tr -d '</' | tr -d ':' | sed -e 's,s, seconds,' -e 's,m, minutes,')
	t=${t:-unlimited}
	tx=$(grep -i 'transmitted' <<<"$html" | awk -F 'td>' '{print $4}' | tr -d '</')
	rx=$(grep -i 'received' <<<"$html" | awk -F 'td>' '{print $4}' | tr -d '</')
fi

if grep -q hotsplots <<<"$html"; then
	vendor=hotsplots
	html=$(sed 's,\/tr>,\/tr>\n,g' <<<"$html")
	logged_in=$(grep -qi 'eingeloggt seit' <<<"$html" && echo 1 || echo 0)
	t=$(grep -i 'verbleibende zeit' <<<"$html" | awk -F 'td>' '{print $3}' | tr -d '</' | sed -e 's,&nbsp,,' -e 's,h, hours,' -e 's,min, minutes,' -e 's,sec, seconds,')
	t=${t:-unlimited}
	tx=$(grep -i 'übertragene daten' <<<"$html" | awk -F 'td>' '{print $3}' | tr -d '</' | sed -e 's,&nbsp,,' -e 's, (.*),,')
	rx="-"
	name=$(grep -i 'loginHead' <<<"$html" | awk -F 'h2>' '{print $2}' | tr -d '</')
fi

# end of hotspot vendor implementations

if [ "$logged_in" -eq 0 ]; then
	echo "not logged in" >&2
	echo "open" "$gateway" "and complete hotspot sign in process" >&2
	echo "" >&2
	exit 1
fi

if [ -z "$t" ]; then
	echo "no hotspot or unimplemented vendor" >&2
	exit 1
fi

if [ "$t" != "unlimited" ]; then
	expiry_time=$(date --date "now + $t" +%s)
	remaining=$(((expiry_time - $(date +%s))))

	if [ -n "$print_time_diff" ]; then
		echo "$remaining"
		exit 0
	fi

	# format remaining time like: 5h30m or 10s
	remaining=$(awk '{
		s=$0
		h=(s/60/60);
		if(h>1){ printf "%dh", h }
		m=(s/60%60)
		if(m>1){ printf "%dm", m }
		if(h<1 && m<1){ printf "%ds", $0 }
	}' <<<"$remaining")
else
	remaining=$t
fi

if [ -n "$print_json" ]; then
	jq -n --args '{
		remaining:$ARGS.positional[0],
		tx:$ARGS.positional[1],
		rx:$ARGS.positional[2],
		t:$ARGS.positional[3],
		vendor:$ARGS.positional[4],
		name:$ARGS.positional[5]
	}' "$remaining" "$tx" "$rx" "$t" "$vendor" "$name"
else
	echo "$remaining"
	echo "TX:" "$tx"
	echo "RX:" "$rx"
	echo "[" "$name" "]"
fi