#!/bin/sh

#-------------------------------------------------------------------------------
cleanup ()
{
	rm $backlog
	rm ${backlog}.new
	rm $m3u8
	rm $segment
}
trap cleanup HUP INT QUIT ABRT PIPE TERM EXIT
#-------------------------------------------------------------------------------

python=/nyan/python3/current/bin/python3
yd="$python /root/bin/y"
curl=/nyan/curl/current/bin/curl
m3u8="/run/$1"
backlog="/run/$1_backlog"

fmt=${2:-best}
hls=$($python /root/bin/y -g -f $fmt "https://www.twitch.tv/$1")
if test -z "$hls"; then
	exit 1
fi

rm -f $m3u8
$curl -s -S -o $m3u8 $hls >/dev/null
if test $? -ne 0; then
	echo "unable to download the m3u8 hls playlist $hls"
	exit 1
fi
if ! egrep '^#EXTM3U' <$m3u8 >/dev/null; then
	echo "the downloaded file $m3u8 is not a m3u8 playlist"
	exit 1
fi

truncate -s 0 $backlog

while true; do
	while IFS= read -r line; do
		if echo "$line" | egrep '^http' >/dev/null; then
			if ! echo "$line" | grep -F -f $backlog >/dev/null; then
				segment=$(mktemp -p /run)
				$curl -m 8 --retry 3 --retry-delay 1 -s -S "$line" >$segment
				ret=$?
				if test $ret -eq 23; then # write error/keep it explicit
					echo "unable to write segment $segment"
					rm -f $segment
					exit 1
				elif test $ret -ne 0; then
					echo "unable to download segment $segment"
					rm -f $segment
					exit 1
				fi
				if ! cat $segment; then
					echo "unable to pipe the segment $segment"
					rm -f $segment
					exit
				fi
				rm -f $segment
				echo "$line" >>$backlog
			fi
		fi
	done <$m3u8

	if test $(wc -l <$backlog) -gt 400 ; then
		tail -n 200 $backlog >${backlog}.new
		mv -f ${backlog}.new $backlog
		rm -f ${backlog}.new
	fi

	rm -f $m3u8
	$curl -m 8 --retry 3 --retry-delay 1 -s -S -o $m3u8 $hls >/dev/null
	if test $? -ne 0; then
		echo "unable to download the m3u8 hls playlist $hls"
		exit
	fi
	if ! egrep '^#EXTM3U' <$m3u8 >/dev/null; then
		echo "the downloaded file $m3u8 is not a m3u8 playlist"
		exit
	fi
done