#!/bin/sh
#
# snd2img converter
# by pasp <pasp@users.sourceforge.net>
#
# last update: Sun Aug  5 01:13:11 CEST 2007
#

# default settings
outputformat=eps
skip=1
title=false
extendedtitle=false
amplitudelabel=false
normalize=false

# ------------------------------------------------------------------------
# functions

check_tools () {

tools_paths=( /usr/bin/sox /usr/bin/gnuplot )     # change paths if needed

for tool in ${tools[@]}
do
    if [ ! -e $tool ];
    then
        error "$tool not found."
    fi
done
}

header () {
    echo "snd2img - sound file to image converter"
    echo "by pasp <pasp@users.sourceforge.net>"
    echo ""
}

error () {
    echo ""
    echo "ERROR: $1"
    exit -1
}

set_title () {
    if [ $title == "true" ];
    then
        echo "set title '"${1%.*}"'" >> $script
    else if [ $extendedtitle == "true" ];
    then
        echo "set title '$1 ($channels_str, $rate_str)'" >> $script
        fi
    fi
}

# ------------------------------------------------------------------------
# MAIN

check_tools

if [ $# -lt "1" ]  # filename passed to script ?
then
    header
    echo "usage: `basename $0` [options] filename"
    echo ""
    echo "options:"
    echo "   -d <n> : draw every n-th sample"
    echo "   -s     : generate SVG figure (default is EPS)"
    echo "   -a     : enable amplitude label"
    echo "   -t     : use filename without extension as title"
    echo "   -e     : use filename with extension,"
    echo "            number of channels and sample rate as title"
    echo "   -n     : set amplitude axis to <-1,1> range"
    exit
fi

set -- `getopt d:snate "$@"`

counter=$#
while [ $counter -gt 1 ]
do
    case "$1" in
        -d)
            skip=$2;
            shift;
            let counter=counter-1;;
        -s)
            outputformat=svg;;
        -a)
            amplitudelabel=true;;
        -t)
            title=true;;
        -e)
            extendedtitle=true;;
        -n)
            normalize=true;;
    esac

    shift
    let counter=counter-1
done

if [ $skip -lt "1" ]  # skip > 0 ?
then
    error "n must be greater then zero."
fi

if [ -e "$@" ];
then

    tmpfile=`mktemp`
    script=$tmpfile.gnu

    header
    echo -n "processing..."

    sox "$1" $tmpfile.dat 2>/dev/null

    if [ ! -e $tmpfile.dat ];
    then
        error "Wrong file type."
    fi

    grep -v '^;' $tmpfile.dat > $tmpfile.txt
    rate=`awk 'NR==1 {print $4}' $tmpfile.dat`      # sample rate -> 4th column
    channels=`awk 'NR==2 {print $3}' $tmpfile.dat`  # channels -> 3rd column
    n=${#channels}
    n=$(($n-1))
    channels=`echo $channels | cut -c 1-$n`         # convert to integer

    rate_str=`echo $rate | tr -d [:space:]`Hz
    if [ $channels -eq 1 ];
    then
        channels_str="1 channel"
    else
        channels_str="$channels channels"
    fi

    if [ $outputformat == "eps" ];
    then
        echo "set terminal postscript enhanced 'Helvetica' 14" > $script
    else
        echo "set terminal svg fname 'Helvetica' fsize 14" > $script
    fi

    if [ $normalize == "true" ];
    then
        echo "set yrange [-1:1]" >> $script
    fi

    if [ $amplitudelabel == "true" ];
    then
        echo "set ylabel 'amplitude'" >> $script
    fi

    echo "set nokey" >> $script    # hide legend
    echo "set xzeroaxis" >> $script
    echo "set grid" >> $script
    echo "set xlabel 'time [s]'" >> $script
    echo "set output '"${@%.*}.$outputformat"'" >> $script

    if [ $channels -eq 1 ];
    then
        set_title $@
        echo "plot '$tmpfile.txt' every $skip with lines" >> $script
    else
        echo "set size 1.0, 1.0" >> $script
        echo "set origin 0.0, 0.0" >> $script
        echo "set multiplot" >> $script
        echo "set size 1.0,0.5" >> $script
        echo "set origin 0.0,0.0" >> $script
        echo "plot '$tmpfile.txt' every $skip using 1:3 with lines" >> $script
        echo "set size 1.0,0.5" >> $script
        echo "set origin 0.0,0.5" >> $script
        set_title $@
        echo "set noxlabel" >> $script
        echo "set format x ''" >> $script
        echo "plot '$tmpfile.txt' every $skip using 1:2 with lines" >> $script
        echo "set nomultiplot" >> $script
    fi

    gnuplot < $script
    rm -rf $tmpfile $tmpfile.dat $tmpfile.txt $script
    echo "done"
else
    error "File not found."
fi