#!/bin/bash

usage() {
	echo "Usage: $0 [options] BASEDIR"
	echo "  Accoda tutti i file presenti nella cartella "
	echo "  piu' recente (usando l mtime) all interno di BASEDIR"
	echo ""
	echo "  I file sono messi tutti, ordinati in ordine alfabetico"
	echo ""
	echo "Options:"
	echo "  -p    DIRPREFIX     La directory deve iniziare con questa stringa"
}

pickdir() {
	base=$1
	prefix=$2
	sorting="-r"  # time-based; use "-r" for name-based
	if [[ -z "$prefix" ]]; then
		ls -1d $sorting "$base"/*/|head -n1
	else
		ls -1d $sorting "$base/${prefix}"*/|head -n1
	fi
}

prefix=
while getopts p: opt; do
	case $opt in 
		p)
			prefix=$OPTARG
			;;
	esac
done
shift $((OPTIND-1))
if [[ $# -ne 1 ]]; then
	usage >&2
	exit 2
fi
base=$1
shift

set -e
set -u

if [[ ! -d "$base" ]]; then
	echo "Errore: cartella non esistente" >&2
	usage >&2
	exit 2
fi

pickeddir=$(pickdir "$base" "$prefix")
if [[ -z "$pickeddir" ]]; then
	echo "Errore: cartella vuota" >&2
	exit 2
fi
if [[ ! -d "$pickeddir" ]]; then
	echo "Errore: cartella trovata non esistente ($pickeddir)"
	exit 2
fi

empty=true
while read -r fpath
do
	empty=false
	fpath=$(readlink -f "$fpath")
	echo "file://$fpath"
done < <(find "$pickeddir" -type f -size +10k \( -iname '*.mp3'  -o -iname '*.ogg' \)| sort)

if $empty; then
	echo "Warning: no file output ($pickeddir)" >&2
	exit 1
else
	exit 0
fi