/*
  Copyright (c) 2021 Alex Diener
  
  This software is provided 'as-is', without any express or implied
  warranty. In no event will the authors be held liable for any damages
  arising from the use of this software.
  
  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:
  
  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
  
  Alex Diener alex@ludobloom.com
*/

#include "audiosynth/SignalFilter_delay.h"
#include "utilities/lookup3.h"
#include <math.h>

#define stemobject_implementation SignalFilter_delay

stemobject_vtable_begin();
stemobject_vtable_entry(dispose);
stemobject_vtable_entry(copy);
stemobject_vtable_entry(isEqual);
stemobject_vtable_entry(hash);
stemobject_vtable_entry(initState);
stemobject_vtable_entry(disposeState);
stemobject_vtable_entry(getDecayTime);
stemobject_vtable_entry(getPropertyCount);
stemobject_vtable_entry(getPropertyAtIndex);
stemobject_vtable_entry(getPropertyValueStateless);
stemobject_vtable_entry(setPropertyValue);
stemobject_vtable_entry(transformSample);
stemobject_vtable_end();

SignalFilter_delay * SignalFilter_delay_create(float interval, float falloff, unsigned int repeatCount) {
	stemobject_create_implementation(init, interval, falloff, repeatCount)
}

bool SignalFilter_delay_init(SignalFilter_delay * self, float interval, float falloff, unsigned int repeatCount) {
	call_super(init, self);
	self->interval = interval;
	self->falloff = falloff;
	self->repeatCount = repeatCount;
	return true;
}

void SignalFilter_delay_dispose(SignalFilter_delay * self) {
	call_super_virtual(dispose, self);
}

SignalFilter_delay * SignalFilter_delay_copy(SignalFilter_delay * self) {
	stemobject_copy_implementation(initCopy)
}

bool SignalFilter_delay_isEqual(SignalFilter_delay * self, compat_type(SignalFilter_delay *) compareUntyped) {
	SignalFilter_delay * compare = compareUntyped;
	if (!call_super_virtual(isEqual, self, compare)) {
		return false;
	}
	return compare->interval == self->interval &&
	       compare->falloff == self->falloff &&
	       compare->repeatCount == self->repeatCount;
}

uint32_t SignalFilter_delay_hash(SignalFilter_delay * self, uint32_t initval) {
	initval = hashlittle(&self->interval, sizeof(self->interval), initval);
	initval = hashlittle(&self->falloff, sizeof(self->falloff), initval);
	initval = hashlittle(&self->repeatCount, sizeof(self->repeatCount), initval);
	return initval;
}

void SignalFilter_delay_initCopy(SignalFilter_delay * self, SignalFilter_delay * original) {
	call_super(initCopy, self, (SignalFilter *) original);
	self->interval = original->interval;
	self->falloff = original->falloff;
	self->repeatCount = original->repeatCount;
}

#define DELAY_SAMPLE_COUNT_MAX 88200
#define PROPERTY_INDEX_INTERVAL 0
#define PROPERTY_INDEX_FALLOFF 1

struct SignalFilter_delay_state {
	float properties[2];
	float sampleBuffer[DELAY_SAMPLE_COUNT_MAX];
	unsigned int bufferedSampleCount;
};

SamplerObject_state * SignalFilter_delay_initState(SignalFilter_delay * self) {
	struct SignalFilter_delay_state * stateStruct = malloc(sizeof(*stateStruct));
	stateStruct->properties[PROPERTY_INDEX_INTERVAL] = self->interval;
	stateStruct->properties[PROPERTY_INDEX_FALLOFF] = self->falloff;
	stateStruct->bufferedSampleCount = 0;
	memset(stateStruct->sampleBuffer, 0, DELAY_SAMPLE_COUNT_MAX * sizeof(*stateStruct->sampleBuffer));
	return stateStruct;
}

void SignalFilter_delay_disposeState(SignalFilter_delay * self, SamplerObject_state * state) {
	free(state);
}

float SignalFilter_delay_getDecayTime(SignalFilter_delay * self) {
	return self->interval * self->repeatCount;
}

static SynthProperty synthProperties[2];

static void initSynthProperties(void) {
	SYNTH_PROPERTY(0, interval, "Interval", 0.01f, 0.5f, 0.25f, 0.05f)
	SYNTH_PROPERTY(1, falloff,  "Falloff",  0.0f, 1.0f, 0.5f, 0.05f)
}

SYNTH_PROPERTY_FUNCTION_IMPLEMENTATIONS()

float SignalFilter_delay_getPropertyValueStateless(SignalFilter_delay * self, SynthPropertyIdentifier propertyIdentifier) {
	switch (propertyIdentifier.propertyIndex) {
		case 0:
			return self->interval;
		case 1:
			return self->falloff;
	}
	return 0.0f;
}

void SignalFilter_delay_setPropertyValue(SignalFilter_delay * self, SamplerObject_state * state, SynthPropertyIdentifier propertyIdentifier, float value) {
	struct SignalFilter_delay_state * stateStruct = state;
	stateStruct->properties[propertyIdentifier.propertyIndex] = value;
}

float SignalFilter_delay_transformSample(SignalFilter_delay * self, SamplerObject_state * state, float sample, float time, float timeDelta) {
	struct SignalFilter_delay_state * stateStruct = (struct SignalFilter_delay_state *) state;
	float interval = stateStruct->properties[PROPERTY_INDEX_INTERVAL];
	float falloff = stateStruct->properties[PROPERTY_INDEX_FALLOFF];
	stateStruct->sampleBuffer[stateStruct->bufferedSampleCount % DELAY_SAMPLE_COUNT_MAX] = sample;
	stateStruct->bufferedSampleCount++;
	unsigned int sampleOffsetPerRepeat = interval / timeDelta;
	for (unsigned int repeatIndex = 0; repeatIndex < self->repeatCount; repeatIndex++) {
		sample += stateStruct->sampleBuffer[(stateStruct->bufferedSampleCount + DELAY_SAMPLE_COUNT_MAX - sampleOffsetPerRepeat * repeatIndex) % DELAY_SAMPLE_COUNT_MAX] * powf(falloff, repeatIndex + 1);
	}
	return sample;
}