/*
  An LV2 plugin to modulate a frequency by a signal.
  Copyright 2011 David Robillard
  Copyright 2002 Mike Rawes

  This is free software: you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This software is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this software.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <stdlib.h>
#include "lv2/lv2plug.in/ns/lv2core/lv2.h"
#include "math_func.h"

#define FMOD_FREQUENCY 0
#define FMOD_MODULATOR 1
#define FMOD_OUTPUT    2

typedef struct {
	float* frequency;
	float* modulator;
	float* output;
} Fmod;

static void
cleanup(LV2_Handle instance)
{
	free(instance);
}

static void
connect_port(LV2_Handle instance,
             uint32_t   port,
             void*      data)
{
	Fmod* plugin = (Fmod*)instance;

	switch (port) {
	case FMOD_FREQUENCY:
		plugin->frequency = data;
		break;
	case FMOD_MODULATOR:
		plugin->modulator = data;
		break;
	case FMOD_OUTPUT:
		plugin->output = data;
		break;
	}
}

static LV2_Handle
instantiate(const LV2_Descriptor*     descriptor,
            double                    sample_rate,
            const char*               bundle_path,
            const LV2_Feature* const* features)
{
	Fmod* plugin = (Fmod*)malloc(sizeof(Fmod));

	return (LV2_Handle)plugin;
}

static void
runFmod_fama_oa(LV2_Handle instance,
                uint32_t   sample_count)
{
	Fmod* plugin = (Fmod*)instance;

	/* Frequency to Modulate (array of floats of length sample_count) */
	float* frequency = plugin->frequency;

	/* LFO Input (array of floats of length sample_count) */
	float* modulator = plugin->modulator;

	/* Output Frequency (array of floats of length sample_count) */
	float* output = plugin->output;

	float freq;
	float mod;
	float scale;

	for (uint32_t s = 0; s < sample_count; ++s) {
		freq = frequency[s];
		mod  = modulator[s];

		scale = (float)EXPF(M_LN2 * mod);

		output[s] = scale * freq;
	}
}

static void
runFmod_famc_oa(LV2_Handle instance,
                uint32_t   sample_count)
{
	Fmod* plugin = (Fmod*)instance;

	/* Frequency to Modulate (array of floats of length sample_count) */
	float* frequency = plugin->frequency;

	/* Shift (Octaves) (float value) */
	float modulator = *(plugin->modulator);

	/* Output Frequency (array of floats of length sample_count) */
	float* output = plugin->output;

	float freq;
	float scale = (float)EXPF(M_LN2 * modulator);

	for (uint32_t s = 0; s < sample_count; ++s) {
		freq = frequency[s];

		output[s] = scale * freq;
	}
}

static void
runFmod_fcma_oa(LV2_Handle instance,
                uint32_t   sample_count)
{
	Fmod* plugin = (Fmod*)instance;

	/* Frequency to Modulate (float value) */
	float frequency = *(plugin->frequency);

	/* LFO Input (array of floats of length sample_count) */
	float* modulator = plugin->modulator;

	/* Output Frequency (array of floats of length sample_count) */
	float* output = plugin->output;

	float mod;
	float scale;

	for (uint32_t s = 0; s < sample_count; ++s) {
		mod = modulator[s];

		scale = (float)EXPF(M_LN2 * mod);

		output[s] = scale * frequency;
	}
}

static void
runFmod_fcmc_oc(LV2_Handle instance,
                uint32_t   sample_count)
{
	Fmod* plugin = (Fmod*)instance;

	/* Frequency to Modulate (float value) */
	float frequency = *(plugin->frequency);

	/* Shift (Octaves) (float value) */
	float modulator = *(plugin->modulator);

	/* Output Frequency (pointer to float value) */
	float* output = plugin->output;

	float scale;

	scale = (float)EXPF(M_LN2 * modulator);

	output[0] = scale * frequency;
}

static const LV2_Descriptor descriptor = {
	"http://drobilla.net/plugins/blip/fmod",
	instantiate,
	connect_port,
	NULL,
	runFmod_fcmc_oc,
	NULL,
	cleanup,
	NULL,
};

LV2_SYMBOL_EXPORT const LV2_Descriptor*
lv2_descriptor(uint32_t index)
{
	switch (index) {
	case 0:  return &descriptor;
	default: return NULL;
	}
}