/*
  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/WaveModifier_supersample.h"
#include "utilities/lookup3.h"
#include <math.h>

#define stemobject_implementation WaveModifier_supersample

stemobject_vtable_begin();
stemobject_vtable_entry(dispose);
stemobject_vtable_entry(copy);
stemobject_vtable_entry(isEqual);
stemobject_vtable_entry(hash);
stemobject_vtable_entry(sample);
stemobject_vtable_end();

WaveModifier_supersample * WaveModifier_supersample_create(unsigned int sampleCount) {
	stemobject_create_implementation(init, sampleCount)
}

bool WaveModifier_supersample_init(WaveModifier_supersample * self, unsigned int sampleCount) {
	call_super(init, self);
	self->sampleCount = sampleCount;
	return true;
}

void WaveModifier_supersample_dispose(WaveModifier_supersample * self) {
	call_super_virtual(dispose, self);
}

WaveModifier_supersample * WaveModifier_supersample_copy(WaveModifier_supersample * self) {
	stemobject_copy_implementation(initCopy)
}

bool WaveModifier_supersample_isEqual(WaveModifier_supersample * self, compat_type(WaveModifier_supersample *) compareUntyped) {
	WaveModifier_supersample * compare = compareUntyped;
	if (!call_super_virtual(isEqual, self, compare)) {
		return false;
	}
	return self->sampleCount == compare->sampleCount;
}

uint32_t WaveModifier_supersample_hash(WaveModifier_supersample * self, uint32_t initval) {
	initval = hashlittle(&self->sampleCount, sizeof(self->sampleCount), initval);
	return initval;
}

void WaveModifier_supersample_initCopy(WaveModifier_supersample * self, WaveModifier_supersample * original) {
	call_super(initCopy, self, (WaveModifier *) original);
	self->sampleCount = original->sampleCount;
}

float WaveModifier_supersample_sample(WaveModifier_supersample * self, SamplerObject_state * state, float phase, float phaseDelta, float time, float timeDelta) {
	struct WaveModifier_state * stateStruct = state;
	float blend = stateStruct->properties[0];
	SamplerObject_state * upstreamState = stateStruct->upstreamState;
	if (blend == 0.0f || self->sampleCount < 2) {
		return call_virtual(sample, self->upstream, upstreamState, phase, phaseDelta, time, timeDelta);
	}
	unsigned int sampleCount = self->sampleCount;
	time -= timeDelta;
	timeDelta /= sampleCount;
	phase -= phaseDelta;
	phaseDelta /= sampleCount;
	float sample = 0.0f;
	for (unsigned int sampleIndex = 0; sampleIndex < sampleCount - 1; sampleIndex++) {
		sample += call_virtual(sample, self->upstream, upstreamState, phase, phaseDelta, time, timeDelta);
		time += timeDelta;
		phase += phaseDelta;
	}
	float lastSample = call_virtual(sample, self->upstream, upstreamState, phase, phaseDelta, time, timeDelta);
	sample += lastSample;
	return sample / sampleCount * blend + lastSample * (1.0f - blend);
}