/*
  An LV2 plugin to generate a non-bandlimited square waveform with gate for
  trigger and sync.
  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/ext/morph/morph.h"
#include "lv2/lv2plug.in/ns/lv2core/lv2.h"
#include "uris.h"

#define SYNCSQUARE_FREQUENCY 0
#define SYNCSQUARE_GATE      1
#define SYNCSQUARE_OUTPUT    2

typedef struct {
	float*   frequency;
	float*   gate;
	float*   output;
	float    srate;
	float    nyquist;
	float    phase;
	uint32_t frequency_is_cv;
	URIs     uris;
} SyncSquare;

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

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

	switch (port) {
	case SYNCSQUARE_FREQUENCY:
		plugin->frequency = data;
		break;
	case SYNCSQUARE_GATE:
		plugin->gate = data;
		break;
	case SYNCSQUARE_OUTPUT:
		plugin->output = data;
		break;
	}
}

static LV2_Morph_Status
morph_port(LV2_Handle                      instance,
           uint32_t                        port,
           LV2_URID                        type,
           const LV2_Morph_Property*const* properties)
{
	SyncSquare* plugin = (SyncSquare*)instance;

	switch (port) {
	case SYNCSQUARE_FREQUENCY:
		if (type == plugin->uris.lv2_ControlPort) {
			plugin->frequency_is_cv = 0;
		} else if (type == plugin->uris.lv2_CVPort) {
			plugin->frequency_is_cv = 1;
		} else {
			return LV2_MORPH_ERR_BAD_TYPE;
		}
		return LV2_MORPH_SUCCESS;
	default:
		return LV2_MORPH_ERR_BAD_PORT;
	}

	return LV2_MORPH_SUCCESS;
}

static LV2_Handle
instantiate(const LV2_Descriptor*     descriptor,
            double                    sample_rate,
            const char*               bundle_path,
            const LV2_Feature* const* features)
{
	SyncSquare* plugin = (SyncSquare*)malloc(sizeof(SyncSquare));
	if (!plugin) {
		return NULL;
	}

	plugin->srate           = (float)sample_rate;
	plugin->nyquist         = (float)(sample_rate / 2.0f);
	plugin->frequency_is_cv = 0;
	map_uris(&plugin->uris, features);

	return (LV2_Handle)plugin;
}

static void
activate(LV2_Handle instance)
{
	SyncSquare* plugin = (SyncSquare*)instance;

	plugin->phase = 0.0f;
}

static void
run(LV2_Handle instance,
    uint32_t   sample_count)
{
	SyncSquare* plugin = (SyncSquare*)instance;

	/* Frequency (array of float of length 1 or sample_count) */
	const float* frequency = plugin->frequency;

	/* Gate (array of float of length sample_count) */
	const float* gate = plugin->gate;

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

	/* Instance data */
	float phase   = plugin->phase;
	float srate   = plugin->srate;
	float nyquist = plugin->nyquist;

	for (uint32_t s = 0; s < sample_count; ++s) {
		if (gate[s] > 0.0f) {
			const float freq = frequency[s * plugin->frequency_is_cv];

			if (phase < nyquist) {
				output[s] = 1.0f;
			} else {
				output[s] = -1.0f;
			}

			phase += freq;
			if (phase < 0.0f) {
				phase += srate;
			} else if (phase > srate) {
				phase -= srate;
			}
		} else {
			output[s] = 0.0f;
			phase     = 0.0f;
		}
	}

	plugin->phase = phase;
}

static const void*
extension_data(const char* uri)
{
	static const LV2_Morph_Interface morph = { morph_port, NULL };
	if (!strcmp(uri, LV2_MORPH__interface)) {
		return &morph;
	}
	return NULL;
}

static const LV2_Descriptor descriptor = {
	"http://drobilla.net/plugins/blop/sync_square",
	instantiate,
	connect_port,
	activate,
	run,
	NULL,
	cleanup,
	extension_data,
};

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