#!/bin/bash

# from https://shallowsky.com/blog/linux/command-line-metronome.html

# Usage: metronome bpm [minutes [volume]]
metronome() {
    bpm=$1
    if [[ $bpm == '-h' || $bpm == '--help' || $bpm == '' ]]; then
        echo 'Usage: metronome bpm [minutes [volume]]'
        return
    fi
    minutes=$2
    volume=$3
    if [[ $minutes != '' ]]; then
        beats=$(awk "BEGIN { print $bpm * $minutes }")
    else
        beats='-'
    fi
    if [[ $volume == '' ]]; then
        volume=1
    fi
    echo "BPM $bpm minutes $minutes Volume $volume"
    play -n -c1 synth 0.004 sine 2000 pad $(awk "BEGIN { print 60/$bpm -.004 }") repeat $beats vol $volume
}

metronome $@