#!/bin/sh
set -eu

usage() {
	cat <<-'EOF'
		Usage:
		  collection-for FILE
		  collection-for -h
	EOF
}

help() {
	cat <<-'EOF'


		Options:
		  -h, --help    show this message

		  FILE          the path of the file to get the collection for


		Say the collection of the given file, using the path of FILE.


		Examples:

		  Get "til" for "src/en/til/some-pt.md":

		    $ collection-for src/en/til/some-pt.md
		    til
	EOF
}


for flag in "$@"; do
	case "$flag" in
		--)
			break
			;;
		--help)
			usage
			help
			exit
			;;
		*)
			;;
	esac
done

while getopts 'h' flag; do
	case "$flag" in
		h)
			usage
			help
			exit
			;;
		*)
			usage >&2
			exit 2
			;;
	esac
done
shift $((OPTIND - 1))

. src/lib.sh


FILE="${1:-}"
eval "$(assert_arg "$FILE" 'FILE')"


lang="$(lang-for "$FILE")"
DIR="$(dirname "$FILE")"
if [ "$DIR" = "$CONTENT_PREFIX/$lang" ]; then
	echo
else
	NAME="$(basename "$DIR")"
	NTH="$(
		collections |
			xargs -I% coll2path "$lang" % |
			awk '{ print NR, substr($0, 1, length($0) - 1) }' |
			grep " $NAME$" |
			cut -d' ' -f1
	)"
	collections | awk -vNTH="$NTH" 'NR == NTH'
fi