#ifndef UDO_BPMDETECT
#define UDO_BPMDETECT ##

/*
	BPM detection from trigger

	This file is part of the SONICS UDO collection by Richard Knight 2021
		License: GPL-2.0-or-later
		http://1bpm.net
*/


/*
	Detect a BPM given a stream of pulses

	kdone, kbpm bpmdetect kpulse [, imaxpulses, imintime]

	kdone		outputs 1 when a new BPM has been ascertained
	kbpm		the detected BPM
	kpulse		trigger input
	imaxpulses	number of pulses to consider: will output BPM after this many
	imintime	minimum time between beats to normalise signal
*/
opcode bpmdetect, kk, kjj
	kpulse, imaxpulses, imintime xin
	imax = (imaxpulses == -1) ? 4 : imaxpulses
	imintime = (imintime == -1) ? 0.2 : imintime
	kcycle init 0
	ktimesum init 0
	ktime timeinsts
	klasttime init 0
	kbpm init 0
	kdone init 0
	if (kpulse == 1 && klasttime != 0) then
		kelapsed = ktime - klasttime
		if (kelapsed > imintime) then
			ktimesum += kelapsed
			klasttime = ktime
			kcycle += 1
		endif
	elseif (klasttime == 0) then
		klasttime = ktime
	endif

	if (kcycle >= imax) then
		kcycle = 0
		kbpm = 60 / (ktimesum / imax)
		ktimesum = 0
		kdone = 1
	else
		kdone = 0
	endif
	xout kdone, kbpm
endop

#end