#!/bin/bash

if [[ "$@" == "" ]]; then
    echo "spkplay <items...>"
    echo "    t<bpm>  set tempo to <bpm> beats per minute (default 120)"
    echo "    o<oct>  switch to octave #<oct>"
    echo "    o+  o-  change one octave up or down"
    echo "    l<len>  set note length to 1/<len>th, i.e. l4 for quarter notes."
    echo "    ml mn ms mx  change to legato, normal, staccato or very-staccato playing style"
    echo "    c c+ d- d d+ ... play this note, with the current octave, length, tempo and style"
    echo "    c.      extend note to 3/2 its normal duration"
    echo "    p       pause (with the current length and tempo)"
    echo "    h       enable verbose output (for debugging)"
    
    exit
fi

declare -a beepies
octave=3
tempo=120
length=4
# n=normal (7/8ths), s=staccato (3/4ths), l=legato (1/1)
stac=n

declare -A notefrq;
notefrq['c']=4188
notefrq['c+']=4436
notefrq['d-']=4436
notefrq['d']=4700
notefrq['d+']=4980
notefrq['e-']=4980
notefrq['e']=5276
notefrq['f-']=5276
notefrq['e+']=5588
notefrq['f']=5588
notefrq['f+']=5920
notefrq['g-']=5920
notefrq['g']=6272
notefrq['g+']=6644
notefrq['a-']=6644
notefrq['a']=7040
notefrq['a+']=7460
notefrq['b-']=7460
notefrq['b']=7904
notefrq['b+']=8376
notefrq['p']=10

debug=0

for s in "$@" ; do
	first="${s:0:1}"
	rest="${s:1}"
	(( debug==1 )) && echo "$s"
	case $first in
		h)
			debug=1
			(( debug==1 )) && echo "    debug on"
			;;
		o)
			case $rest in
				+) (( octave++ )) ;;
				-) (( octave-- )) ;;
				*) octave="$rest" ;;
			esac
			(( debug==1 )) && echo "    octave $octave"
			;;
		t)
			tempo=$rest
			(( debug==1 )) && echo "    tempo $tempo"
			;;
		l)
			length=$rest
			(( debug==1 )) && echo "    length 1 / $length"
			;;
		m)
			stac=$rest
			(( debug==1 )) && echo "    music $stac"
			;;
		*)
			#notes
			note="$s"
			extralength="0"
			[[ "${s:(-1):1}" == "." ]] && note="${s:0:(-1)}" && extralength="1";
			
			(( debug==1 )) && echo "    note $note extralength $extralength"
			frq="$(( ${notefrq[$note]} / ( 2 ** ( 8 - octave )  )  ))";
			[[ "$note" == "p" ]] && frq="1";
			fulllen="$(( 2000 * 120 / tempo / length  ))";
			(( extralength == 1 )) && fulllen="$(( fulllen * 3 / 2 ))";
			case $stac in
				n) sndlen="$(( fulllen * 7 / 8 ))"; ;;
				s) sndlen="$(( fulllen * 6 / 8 ))"; ;;
				l) sndlen="$fulllen"; ;;
				x) sndlen="$(( fulllen / 2 ))"; ;;
				*) sndlen="$(( fulllen / 3 ))"; ;;
			esac
			pauslen="$(( fulllen - sndlen ))";
			beepies+=( -n -f $frq -l $sndlen -D $pauslen );
			(( debug==1 )) && echo "    out: frq $frq len $sndlen pau $pauslen"
			;;
	esac
done

# remove the first -n, otherwise beep will not interpret *any* of the arguments
unset -v beepies[0];

beep "${beepies[@]}"