#!/bin/bash

# Simple script to record ambient sounds. recording is paused
# until a sound threshold is reached and stopped after 5 seconds
# of silence.  Sound clip is saved as flac,date/time stamped and
# the process repeated until a specified time duration.

# NOTE: sox is set to use the default audio input.  If using pulseadio,
#       especially with KDE and USB microphone, use 
#       'pulse audio volume control' and mixer to set the correct input source.

# DEPS:
#    bash
#    bc
#    sox
#    flac
#    alsa

START_REC=$SECONDS

AUDIO_PATH=${AUDIO_PATH:-/$HOME/audio}
mkdir -p $AUDIO_PATH

# trap ctrl-c and call ctrl_c()
trap ctrl_c INT

function ctrl_c() {
        echo "terminating script..."
        exit 0
}

# Check if ran with root permissions
if [ `id -u` -eq 0 ]; then
   echo "This script must not be run as root!"
   exit 1
fi

if [ -n "$1" ]; then
    REC_LEN=$(echo "scale=0; ($1*3600)/1" | bc)
    echo "Recording for $1 hours ($REC_LEN seconds)." 
else
    echo "Usage: $0 hours"
    echo "Specify the number of hours script to to run."
    echo "Fractional values are allowed."
    exit 1
fi

while [ $(($SECONDS - $START_REC)) -lt $REC_LEN ]; do
    /usr/bin/rec -S -c 1 -b 16 -r 32000 $AUDIO_PATH/sleep.flac silence 1 0.1 3% 1 5.0 3%
    DATE=$(date +%Y%m%d%H%M%S)
    mv $AUDIO_PATH/sleep.flac $AUDIO_PATH/$DATE-sleep.flac
done
echo "Time expired."