/* PipeWire
 * Copyright (C) 2018 Wim Taymans <wim.taymans@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include <stdio.h>
#include <errno.h>
#include <time.h>
#include <math.h>
#include <sys/mman.h>

#include <spa/support/type-map.h>
#include <spa/param/format-utils.h>
#include <spa/param/audio/format-utils.h>
#include <spa/param/props.h>
#include <spa/lib/debug.h>

#include <pipewire/pipewire.h>

#define M_PI_M2 ( M_PI + M_PI )

#define DEFAULT_RATE		44100
#define DEFAULT_CHANNELS	1

struct type {
	struct spa_type_media_type media_type;
	struct spa_type_media_subtype media_subtype;
	struct spa_type_format_audio format_audio;
	struct spa_type_audio_format audio_format;
};

static inline void init_type(struct type *type, struct spa_type_map *map)
{
	spa_type_media_type_map(map, &type->media_type);
	spa_type_media_subtype_map(map, &type->media_subtype);
	spa_type_format_audio_map(map, &type->format_audio);
	spa_type_audio_format_map(map, &type->audio_format);
}

struct data {
	struct type type;

	struct pw_main_loop *loop;

	struct pw_core *core;
	struct pw_type *t;
	struct pw_remote *remote;
	struct spa_hook remote_listener;

	struct pw_stream *stream;
	struct spa_hook stream_listener;

	struct spa_audio_info_raw format;

	double accumulator;
};

static void fill_f32(struct data *d, void *dest, int avail)
{
	float *dst = dest;
	int n_samples = avail / (sizeof(float) * d->format.channels);
	int i, c;

        for (i = 0; i < n_samples; i++) {
		float val;

                d->accumulator += M_PI_M2 * 440 / d->format.rate;
                if (d->accumulator >= M_PI_M2)
                        d->accumulator -= M_PI_M2;

                val = sin(d->accumulator);

                for (c = 0; c < d->format.channels; c++)
                        *dst++ = val;
        }
}

static void on_need_buffer(void *userdata)
{
	struct data *data = userdata;
	uint32_t id;
	struct spa_buffer *buf;
	uint8_t *p;

	id = pw_stream_get_empty_buffer(data->stream);
	if (id == SPA_ID_INVALID)
		return;

	buf = pw_stream_peek_buffer(data->stream, id);

	if ((p = buf->datas[0].data) == NULL)
		return;

	fill_f32(data, p, buf->datas[0].maxsize);

	buf->datas[0].chunk->size = buf->datas[0].maxsize;

	pw_stream_send_buffer(data->stream, id);
}

static const struct pw_stream_events stream_events = {
	PW_VERSION_STREAM_EVENTS,
	.need_buffer = on_need_buffer,
};

static void on_state_changed(void *_data, enum pw_remote_state old, enum pw_remote_state state, const char *error)
{
	struct data *data = _data;
	struct pw_remote *remote = data->remote;

	switch (state) {
	case PW_REMOTE_STATE_ERROR:
		printf("remote error: %s\n", error);
		pw_main_loop_quit(data->loop);
		break;

	case PW_REMOTE_STATE_CONNECTED:
	{
		const struct spa_pod *params[1];
		uint8_t buffer[1024];
		struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));

		printf("remote state: \"%s\"\n",
		       pw_remote_state_as_string(state));

		data->stream = pw_stream_new(remote, "audio-src", NULL);

		params[0] = spa_pod_builder_object(&b,
			data->t->param.idEnumFormat, data->t->spa_format,
			"I", data->type.media_type.audio,
			"I", data->type.media_subtype.raw,
			":", data->type.format_audio.format,    "I", data->type.audio_format.F32,
			":", data->type.format_audio.channels,  "i", DEFAULT_CHANNELS,
			":", data->type.format_audio.rate,	"i", DEFAULT_RATE);

		data->format.channels = DEFAULT_CHANNELS;
		data->format.rate = DEFAULT_RATE;

		pw_stream_add_listener(data->stream,
				       &data->stream_listener,
				       &stream_events,
				       data);

		pw_stream_connect(data->stream,
				  PW_DIRECTION_OUTPUT,
				  NULL,
				  PW_STREAM_FLAG_AUTOCONNECT |
				  PW_STREAM_FLAG_MAP_BUFFERS,
				  params, 1);
		break;
	}
	default:
		printf("remote state: \"%s\"\n", pw_remote_state_as_string(state));
		break;
	}
}

static const struct pw_remote_events remote_events = {
	PW_VERSION_REMOTE_EVENTS,
	.state_changed = on_state_changed,
};

int main(int argc, char *argv[])
{
	struct data data = { 0, };

	pw_init(&argc, &argv);

	data.loop = pw_main_loop_new(NULL);
	data.core = pw_core_new(pw_main_loop_get_loop(data.loop), NULL);
	data.t = pw_core_get_type(data.core);
	data.remote = pw_remote_new(data.core, NULL, 0);

	init_type(&data.type, data.t->map);

	pw_remote_add_listener(data.remote, &data.remote_listener, &remote_events, &data);

	pw_remote_connect(data.remote);

	pw_main_loop_run(data.loop);

	pw_core_destroy(data.core);
	pw_main_loop_destroy(data.loop);

	return 0;
}