#!/usr/bin/env bash

if [ -z "$1" ]
then
    echo "Usage: $0 <filename>"
    exit 1
fi

SF_FP=0.142125
SF_MP=3.613
SF_LP=11.31725
SF_ELP=31.976875

ECHO_LEVEL=0.3
ECHO_DELAY=0.125
ECHO_FP=0.358
ECHO_MP=0.890375
ECHO_LP=6.514875
ECHO_ELP=33.61525

BG_LEVEL=0.2
BGSF_FP=0.3415
BGSF_MP=1.3145
BGSF_LP=6.82225
BGSF_ELP=37.534875

IF_LEVEL=0.02
IF_FREQ=3125
IF_FP=0.2005
IF_MP=1.017125
IF_LP=8.7015
IF_ELP=20.376

FILENAME=$1
FILTER="[0]highpass=f=200, aecho=delays=$ECHO_LEVEL/1000.0, aeval=val(0) + $ECHO_LEVEL * val(0) * (0.4*sin(t*6.28/$ECHO_ELP) + 0.3*sin(t*6.28/$ECHO_LP) + 0.2*sin(t*6.28/$ECHO_MP) + 0.1*sin(t*6.28/$ECHO_FP))[ECHO], [0]highpass=f=500, aeval=val(0) + val(0) * (0.4*sin(t*6.28/$SF_ELP) + 0.3*sin(t*6.28/$SF_LP) + 0.2*sin(t*6.28/$SF_MP) + 0.1*sin(t*6.28/$SF_FP))[SF], [1]aeval=val(0)*0.1[NOISE], [SF][NOISE]amix[OUT], [OUT][ECHO]amix[OUT2], [OUT2]aeval=val(0) + $IF_LEVEL*sin(t*6.28*$IF_FREQ)*(0.4*sin(t*6.28/$IF_ELP) + 0.3*sin(t*6.28/$IF_LP) + 0.2*sin(t*6.28/$IF_MP) + 0.1*sin(t*6.28/$IF_FP)), lowpass=f=3000"

ffmpeg -ss 20 -i "${FILENAME}" -f u8 -ar 8000 -ac 1 -i /dev/urandom -f u8 -ar 8000 -ac 1 -acodec pcm_u8 -filter_complex "$FILTER" - | ffplay -f u8 -ar 8000 -ac 1 -