#!/bin/bash

# Group media files together to make hour-long chunks
# with the same sample rate.  Ipods crash when things
# are much longer than an hour, but also randomly skip
# tracks.  We want to minimize the number of tracks in
# order to minimize the number of times the listening
# experience is interrupted by suddenly jumping ahead
# and having to fish out the device and hit back twice.

# This leaves things in numbered directories, all lined
# up for use with speedcode.  For example:
#  { for a in ?;do speedcode "foo-$a.mp3" "$a"/*; done; }

factor=1.7 # same as speedcode
while getopts f: opt;do
 case $opt in
  f)    factor=$OPTARG;;
 esac
done
shift `expr $OPTIND - 1`



media-length -r "$@" | awk -v limit="$(dc <<< "3600 $factor *p")" '
	BEGIN {
		dest=1
		printf "%02d", dest | "xargs -0 mkdir -v"
		close("xargs -0 mkdir -v")
	}
	{
		if ((prevrate && $1 != prevrate) ||
		    (total && total + $2 > limit)) {
			print "===="
			print "total:", total
			print ""
			total=0

			dest++
			printf "%02d", dest | "xargs -0 mkdir -v"
			close("xargs -0 mkdir -v")
		}
		prevrate = $1
		total += $2
		printf "%s\t%s\t", $1, $2
		printf "%s\0%02d", gensub("^[0-9]+ [0-9.]+\t", "", 1), dest | "xargs -0 mv -v "
		close("xargs -0 mv -v ")
	}'