#!/bin/sh

_printhelp ()
{
    cat<<EOF
Usage: ${1##*/} [-p PROC] ROOT [OPTIONS]

This will batch-process all audio files found in ROOT folder and subfolders with
the tc-audio-transcode script.

All OPTIONS are passed to tc-audio-transcode.  For more details see

  tc-audio-transcode -h

This script has the ability to run multiple processes. The number or processes
defaults to the number of online cores if 'lscpu' is found, or to 1
otherwise. The number of parallel processes is bounded by the number of input
files. Outputting from several processes at the same time to the standard output
is not convenient, therefore when more than 1 process is started, the output is
disabled (except for errors).

If you still want the output, you need to restrict the number of processes to
1. For instance to preview changes in current folder you would write:

  ${1##*/} -p1 . -p

Options:

  -p PROC: run PROC processes in parallel.

EOF
}

if [ -n "$(command -v lscpu)" ]; then
    ## lscpu is a Linux util also available on *BSD.
    CPUNO=$(lscpu  | awk '/^CPU\(s\)/ {print $2;exit}')
else
    CPUNO=1
fi

while getopts ":p:h" opt; do
    case $opt in
        h)
            _printhelp "$0"
            exit 1 ;;
        p)
            CPUNO=$OPTARG ;;
        ?)
            _printhelp "$0"
            exit 1 ;;
        :)
            _printhelp "$0"
            exit 1 ;;
    esac
done

shift $(($OPTIND - 1))
if [ $# -eq 0 ]; then
    _printhelp "$0"
    exit 1
fi

ROOT="$1"
shift

if [ -z "$(command -v ffmpeg)" ]; then
    echo "ffmpeg required."
    exit
fi

if [ ! -f "${0%/*}/titlecase.awk" ]; then
    echo "AWK titlecase script required."
    exit
fi

if [ ! -f "${0%/*}/tc-audio-transcode" ]; then
    echo "tc-audio-transcode script required."
    exit
fi

INPUT="$(find "."  \( \
    -iname '*.aac'  -o \
    -iname '*.ape'  -o \
    -iname '*.flac' -o \
    -iname '*.ogg'  -o \
    -iname '*.mp3'  -o \
    -iname '*.mp4'  -o \
    -iname '*.mpc'  -o \
    -iname '*.wav'  -o \
    -iname '*.wv'   \) | sort -n)"

_worker()
{
    CORE=$1
    shift

    ## WARNING: ffmpeg should not be called from within a while<<EOF loop since
    ## it continues to read input while running.
    OLDIFS=$IFS
    IFS="
"

    for file in $(echo "$INPUT" | sed -n "$CORE~${CPUNO}p"); do
        if [ -n "$file" ]; then
            echo "$(tput setf 2)$(tput bold)==>$(tput sgr0) $file"

            [ $CPUNO -eq 1 ] && "${0%/*}"/tc-audio-transcode "$@" "$file" || \
                tc-audio-transcode -q "$@" "$file" >/dev/null
        fi
    done
    IFS=$OLDIFS

    echo "$(tput setf 5)$(tput bold)::$(tput sgr0) Thread $CORE/$CPUNO terminated."
}

FILENO=$(echo "$INPUT" | wc -l)
if [ $CPUNO -gt $FILENO ]; then
    CPUNO=$FILENO
fi

for i in $(seq 2 $CPUNO); do
    _worker $i "$@" &
done

## We run one worker in the current process so that this script will hopefully
## terminate when the last job finishes.
_worker 1 "$@"