#!/bin/sh
# invidious
# Written in 2019 by Leslie
# Modified in 2019-2020 by Lucas
# CC0 1.0 Universal/Public domain - No rights reserved
#
# To the extent possible under law, the author(s) have dedicated all
# copyright and related and neighboring rights to this software to the
# public domain worldwide. This software is distributed without any
# warranty. You should have received a copy of the CC0 Public Domain
# Dedication along with this software. If not, see
# <http://creativecommons.org/publicdomain/zero/1.0/>.

usage()
{
	printf "Usage: [-T] %s url\n" "${0##*/}" >&2
	exit 1
}

err()
{
	printf "%s: %s\n" "${0##*/}" "$*" >&2
	exit 1
}

fetch_file()
{
	# Assumes utility supports `-o output_file`
	case $(uname) in
	OpenBSD)
		$torsocks ftp -MV "$@"
		;;
	*)
		$torsocks curl -fLSs "$@"
		;;
	esac
}

api()
{
	printf "https://%s%s\n" "$INVIDIOUS" "$*"
}

known_site()
{
	printf "%s\n" "$1" | grep -Eq \
	    -e "^https?://(www\.)?youtube\.com/" \
	    -e "^https?://youtu\.be/" \
	    -e "^https?://(www\.)?invidio\.us/" \
	    -e "^https?://invidious\.snopyta\.org/" \
	    -e "^https?://yewtu\.be/"
}

get_id_path()
{
	printf "%s\n" "${1##*/}"
}

get_id_query()
{
	oldIFS=$IFS
	IFS="&"
	set -- ${1##*"?"}
	IFS=$oldIFS

	id=
	for param; do
		case $param in
		v=*)
			id=${param#v=}
			break
			;;
		esac
	done

	printf "%s\n" "$id"
}

get_id()
{
	case $1 in
	*"?v="*)
		get_id_query "$1"
		;;
	*)	get_id_path "$1"
		;;
	esac
}

: ${INVIDIOUS:=invidious.snopyta.org}

torsocks=torsocks
while getopts T flag; do
	case $flag in
	T)	torsocks= ;;
	*)	usage ;;
	esac
done
shift $((OPTIND - 1))
[ $# -eq 1 ] || usage

url=$1
known_site "$url" || err "unknown site $url"

id=$(get_id "$url")
[ ${#id} -eq 11 ] || err "invalid video ID $id"

# XXX choose in some clever way
itag=$(fetch_file -o - "$(api "/api/v1/videos/$id")" |
    jq -r ".formatStreams[].itag" | head -n 1)
api "/latest_version?id=$id&itag=$itag"