MFD_FILTER(ntapdelay)

#ifdef MX_TTF

	mflt:ntapdelay
	TTF_DEF("MIDI N-Tap Delay", "MIDI N-Tap Delay", ; atom:supports time:Position)
	, TTF_IPORT(0, "channelf", "Filter Channel", 0, 16, 0,
			PORTENUMZ("Any")
			DOC_CHANF)
	, TTF_IPORT( 1, "bpmsrc",  "BPM source", 0, 1, 1,
			lv2:scalePoint [ rdfs:label "Control Port" ; rdf:value 0 ] ;
			lv2:scalePoint [ rdfs:label "Plugin Host (if available)" ; rdf:value 1 ] ;
			lv2:portProperty lv2:integer; lv2:portProperty lv2:enumeration;
			)
	, TTF_IPORT(2, "delayBPM",  "BPM", 1.0, 280.0,  120.0, units:unit units:bpm;
			rdfs:comment "base unit for the delay-time")
	, TTF_IPORT(3, "delayBeats", "Repeat-time in beats", .00390625, 16.0,  1.0,
			lv2:scalePoint [ rdfs:label "32th" ; rdf:value 0.125 ] ;
			lv2:scalePoint [ rdfs:label "16th" ; rdf:value 0.25 ] ;
			lv2:scalePoint [ rdfs:label "Eighth" ; rdf:value 0.5 ] ;
			lv2:scalePoint [ rdfs:label "Quarter" ; rdf:value 1.0 ] ;
			lv2:scalePoint [ rdfs:label "Half Note" ; rdf:value 2.0 ] ;
			lv2:scalePoint [ rdfs:label "Whole Note" ; rdf:value 4.0 ] ;
			lv2:scalePoint [ rdfs:label "Two Bars" ; rdf:value 8.0 ] ;
			lv2:scalePoint [ rdfs:label "Four Bars" ; rdf:value 16.0 ] ;
			rdfs:comment "delay length in base-units")
	, TTF_IPORT(4, "taps",  "Repeats", 0, 64, 3, lv2:portProperty lv2:integer;
			lv2:scalePoint [ rdfs:label "until note-off" ; rdf:value 0 ] ;
			rdfs:comment "Number of repeats")
	, TTF_IPORT(5, "velocityadj",  "velocity ramp", -64.0, 64.0, -10.0,
			rdfs:comment "Velocity change per repeat")
	; rdfs:comment "This effect repeats notes N times. Where N is either a fixed number or unlimited as long as a given key is pressed. BPM and delay-time variable allows tempo-ramps. On every repeat the given velocity-adjustment is added or subtracted, the result is clamped between 1 and 127."
	.

#elif defined MX_CODE

static void
filter_cleanup_ntapdelay(MidiFilter* self)
{
	free(self->memQ);
}

static inline void filter_ntapdelay_panic(MidiFilter* self, const uint8_t c, const uint32_t tme) {
	int i,k;
	const int max_delay = self->memI[0];
	for (i=0; i < max_delay; ++i) {
		if (self->memQ[i].size == 3
				&& (self->memQ[i].buf[0] & 0xf0) != 0xf0
				&& (self->memQ[i].buf[0] & 0x0f) != c)
			continue;
		self->memQ[i].size = 0;
	}

	for (k=0; k < 127; ++k) {
		if (self->memCS[c][k]) {
			uint8_t buf[3];
			buf[0] = MIDI_NOTEOFF | c;
			buf[1] = k; buf[2] = 0;
			forge_midimessage(self, tme, buf, 3);
		}
		self->memCS[c][k] = 0; // count note-on per key post-delay
		self->memCM[c][k] = 0; // remember velocity of note-on
		self->memCI[c][k] = -1; // remember time of note-on
	}
}

void
filter_midi_ntapdelay(MidiFilter* self,
		const uint32_t tme,
		const uint8_t* const buffer,
		const uint32_t size)
{
	int i;
	float bpm = MAX(*self->cfg[2], 1.0);
	if (*self->cfg[1] && (self->available_info & NFO_BPM)) {
		bpm = self->bpm;
	}
	if (bpm <= 0) bpm = 60;

	if (midi_is_panic(buffer, size)) {
		filter_ntapdelay_panic(self, buffer[0]&0x0f, tme);
	}

	const uint8_t chs = midi_limit_chn(floorf(*self->cfg[0]) -1);
	const uint8_t chn = buffer[0] & 0x0f;
	uint8_t mst = buffer[0] & 0xf0;

	if (size != 3
			|| !(mst == MIDI_NOTEON || mst == MIDI_NOTEOFF || mst == MIDI_POLYKEYPRESSURE)
			|| !(floorf(*self->cfg[0]) == 0 || chs == chn)
		 )
	{
		forge_midimessage(self, tme, buffer, size);
		return;
	}

	if ((self->memI[2] + 1) % self->memI[0] == self->memI[1]) {
		forge_midimessage(self, tme, buffer, size);
		return;
	}

	const float grid = RAIL((*self->cfg[3]), 1/256.0, 4.0);
	const double samples_per_beat = 60.0 / bpm * self->samplerate;
	const uint8_t key = buffer[1] & 0x7f;
	const uint8_t vel = buffer[2] & 0x7f;

	uint8_t buf[3];
	memcpy(buf, buffer, 3);

	/* treat note-on w/velocity==0 as note-off */
	if (mst == MIDI_NOTEON && vel == 0) {
		mst = MIDI_NOTEOFF;
		buf[0] = MIDI_NOTEOFF | chn;
	}

	if (mst == MIDI_NOTEON) {
		self->memCI[chn][key] = tme + rint(grid * samples_per_beat);
		self->memCM[chn][key] = vel;
		if (self->memCS[chn][key] == 0) {
				self->memCS[chn][key]++; // key active
				forge_midimessage(self, tme, buffer, size);
		}
	}
	else if (mst == MIDI_NOTEOFF) {
		self->memCI[chn][key] = -1;
		self->memCM[chn][key] = 0;
		if (self->memCS[chn][key] > 0) {
			self->memCS[chn][key]--;
			if (self->memCS[chn][key] == 0) {
				forge_midimessage(self, tme, buffer, size);
			}
		}

	} else {
		forge_midimessage(self, tme, buffer, size);
	}

	for (i=0; i < RAIL(*self->cfg[4], 0, 128); ++i) {
		int delay = rint(grid * samples_per_beat * (i+1.0));
		if (mst == MIDI_NOTEON) {
			buf[2] = RAIL(rintf(vel + (i+1.0) * (*self->cfg[5])), 1, 127);
		} else {
			buf[2] = vel;
		}
		MidiEventQueue *qm = &(self->memQ[self->memI[2]]);
		memcpy(qm->buf, buf, 3);
		qm->size = size;
		qm->reltime = tme + delay;
		self->memI[2] = (self->memI[2] + 1) % self->memI[0];

		if ((self->memI[2] + 1) % self->memI[0] == self->memI[1]) {
			return;
		}
	}
}

static void
filter_preproc_ntapdelay(MidiFilter* self)
{
	int i,c,k;

	if (*self->cfg[4] != 0 && self->lcfg[4] == 0) for (c=0; c < 16; ++c) for (k=0; k < 127; ++k) {
		self->memCM[c][k] = 0; // remember velocity of note-on
		self->memCI[c][k] = -1; // remember time of note-on
	}

	float newbpm = MAX(*self->cfg[2], 1.0);
	if (*self->cfg[1] && (self->available_info & NFO_BPM)) {
		newbpm = self->bpm;
	}
	if (newbpm <= 0) newbpm = 60;

	if (self->memF[0] == newbpm && *self->cfg[2] == self->lcfg[2]) return;

	const float oldbpm = self->memF[0];
	self->memF[0] = newbpm;

	const float old_grid = RAIL((self->lcfg[3]), 1/256.0, 16.0);
	const double old_samples_per_beat = 60.0 / oldbpm * self->samplerate;
	const float new_grid = RAIL((*self->cfg[3]), 1/256.0, 16.0);
	const double new_samples_per_beat = 60.0 / newbpm * self->samplerate;

	const double fact = (new_grid * new_samples_per_beat) / (old_grid * old_samples_per_beat);

	const int max_delay = self->memI[0];
	const int roff = self->memI[1];
	const int woff = self->memI[2];

	for (i=0; i < max_delay; ++i) {
		const int off = (i + roff) % max_delay;
		if (self->memQ[off].size > 0) {
			self->memQ[off].reltime = rint(self->memQ[off].reltime * fact);
		}
		if (off == woff) break;
	}
}

static void
filter_postproc_ntapdelay(MidiFilter* self)
{
	int i,c,k;
	const int max_delay = self->memI[0];
	const int roff = self->memI[1];
	const uint32_t n_samples = self->n_samples;
	int skipped = 0;

	float bpm = MAX(*self->cfg[2], 1.0);
	if (*self->cfg[1] && (self->available_info & NFO_BPM)) {
		bpm = self->bpm;
	}
	if (bpm <= 0) bpm = 60;
	const float grid = RAIL((*self->cfg[3]), 1/256.0, 16.0);
	const double samples_per_beat = 60.0 / bpm * self->samplerate;

	/* add note-on/off for held notes..
	 * TODO: use a preallocated stack-like structure
	 */
	if (*self->cfg[4] == 0) for (c=0; c < 16; ++c) for (k=0; k < 127; ++k) {
		if (self->memCM[c][k] == 0) continue;

		if (self->memCI[c][k] >= n_samples) {
			self->memCI[c][k] -= n_samples;
			continue;
		}

		while (1) {
			self->memCM[c][k] = RAIL(rintf(self->memCM[c][k] + (*self->cfg[5])), 1, 127);
			/* enqueue note-off + note-on */
			MidiEventQueue *qm = &(self->memQ[self->memI[2]]);
			qm->buf[0] = MIDI_NOTEOFF | c;
			qm->buf[1] = k;
			qm->buf[2] = 0;
			qm->size = 3;
			qm->reltime = self->memCI[c][k];
			self->memI[2] = (self->memI[2] + 1) % self->memI[0];
			if ((self->memI[2] + 1) % self->memI[0] == self->memI[1]) {
				self->memCI[c][k] += ceil(grid * samples_per_beat);
				break;
			}

			qm = &(self->memQ[self->memI[2]]);
			qm->buf[0] = MIDI_NOTEON | c;
			qm->buf[1] = k;
			qm->buf[2] = self->memCM[c][k];
			qm->size = 3;
			qm->reltime = self->memCI[c][k];
			self->memI[2] = (self->memI[2] + 1) % self->memI[0];
			if ((self->memI[2] + 1) % self->memI[0] == self->memI[1]) {
				self->memCI[c][k] += ceil(grid * samples_per_beat);
				break;
			}

			self->memCI[c][k] += ceil(grid * samples_per_beat);

			if (self->memCI[c][k] >= n_samples) {
				break;
			}
		}

		self->memCI[c][k] -= n_samples;
	}

	/* sort queue */
	int pidx = -1;
	for (i=0; i < max_delay; ++i) {
		const int off = (i + roff) % max_delay;
		if (off == self->memI[2]) {
			break;
		}
		if (self->memQ[off].size == 0) {
			continue;
		}
		if (self->memQ[off].size > 3) {
			pidx = -1;
			continue;
		}
		if (pidx < 0 || self->memQ[off].reltime >= self->memQ[pidx].reltime) {
			pidx = off;
			continue;
		}
		// swap
		MidiEventQueue tmp;
		memcpy(&tmp, &self->memQ[off], sizeof(MidiEventQueue));
		memcpy(&self->memQ[off], &self->memQ[pidx], sizeof(MidiEventQueue));
		memcpy(&self->memQ[pidx], &tmp, sizeof(MidiEventQueue));
		pidx = off;
	}

	/* dequeue delayline */
	for (i=0; i < max_delay; ++i) {
		const int off = (i + roff) % max_delay;
		if (off == self->memI[2]) break;

		if (self->memQ[off].size > 0) {
			if (self->memQ[off].reltime < n_samples) {

				if (self->memQ[off].size == 3 && (self->memQ[off].buf[0] & 0xf0) == MIDI_NOTEON) {
					const uint8_t chn = self->memQ[off].buf[0] & 0x0f;
					const uint8_t key = self->memQ[off].buf[1] & 0x7f;
					self->memCS[chn][key]++;
					if (self->memCS[chn][key] > 1) { // send a note-off first
						//self->memCS[chn][key]--;
						uint8_t buf[3];
						buf[0] = MIDI_NOTEOFF | chn;
						buf[1] = key; buf[2] = 0;
						forge_midimessage(self, self->memQ[off].reltime, buf, 3);
					}
					forge_midimessage(self, self->memQ[off].reltime, self->memQ[off].buf, self->memQ[off].size);
				}
				else if (self->memQ[off].size == 3 && (self->memQ[off].buf[0] & 0xf0) == MIDI_NOTEOFF) {
					const uint8_t chn = self->memQ[off].buf[0] & 0x0f;
					const uint8_t key = self->memQ[off].buf[1] & 0x7f;
					if (self->memCS[chn][key] > 0) {
						self->memCS[chn][key]--;
						if (self->memCS[chn][key] == 0) {
							forge_midimessage(self, self->memQ[off].reltime, self->memQ[off].buf, self->memQ[off].size);
						}
					}
				} else {
					forge_midimessage(self, self->memQ[off].reltime, self->memQ[off].buf, self->memQ[off].size);
				}

				self->memQ[off].size = 0;
				if (!skipped) self->memI[1] = (self->memI[1] + 1) % max_delay;
			} else {
				self->memQ[off].reltime -= n_samples;
				skipped = 1;
			}
		} else if (!skipped) self->memI[1] = off;
		if (off == self->memI[2]) break;
	}
}

void filter_init_ntapdelay(MidiFilter* self) {
	int c,k;
	srandom ((unsigned int) time (NULL));
	self->memI[0] = MAX(self->samplerate / 8.0, 1024);
	self->memI[1] = 0; // read-pointer
	self->memI[2] = 0; // write-pointer
	self->memQ = calloc(self->memI[0], sizeof(MidiEventQueue));
	self->preproc_fn = filter_preproc_ntapdelay;
	self->postproc_fn = filter_postproc_ntapdelay;
	self->cleanup_fn = filter_cleanup_ntapdelay;

	for (c=0; c < 16; ++c) for (k=0; k < 127; ++k) {
		self->memCS[c][k] = 0; // count note-on per key post-delay
		self->memCM[c][k] = 0; // remember velocity of note-on
		self->memCI[c][k] = -1; // remember time of note-on
	}
	self->memF[0] = 120; // prev bpm
}

#endif