/* Spa */
/* SPDX-FileCopyrightText: Copyright © 2018 Wim Taymans */
/* SPDX-License-Identifier: MIT */

#include <errno.h>
#include <stddef.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>

#include <spa/support/plugin.h>
#include <spa/support/log.h>
#include <spa/support/system.h>
#include <spa/support/loop.h>
#include <spa/utils/list.h>
#include <spa/utils/keys.h>
#include <spa/utils/result.h>
#include <spa/utils/string.h>
#include <spa/node/node.h>
#include <spa/node/utils.h>
#include <spa/node/io.h>
#include <spa/node/keys.h>
#include <spa/param/audio/format-utils.h>
#include <spa/param/param.h>
#include <spa/pod/filter.h>
#include <spa/control/control.h>

#undef SPA_LOG_TOPIC_DEFAULT
#define SPA_LOG_TOPIC_DEFAULT &log_topic
SPA_LOG_TOPIC_DEFINE_STATIC(log_topic, "spa.audiotestsrc");

#define SAMPLES_TO_TIME(this,s)   ((s) * SPA_NSEC_PER_SEC / (port)->current_format.info.raw.rate)
#define BYTES_TO_SAMPLES(this,b)  ((b)/(port)->bpf)
#define BYTES_TO_TIME(this,b)     SAMPLES_TO_TIME(this, BYTES_TO_SAMPLES (this, b))

enum wave_type {
	WAVE_SINE,
	WAVE_SQUARE,
};

#define DEFAULT_RATE		48000
#define DEFAULT_CHANNELS	2

#define DEFAULT_LIVE true
#define DEFAULT_WAVE WAVE_SINE
#define DEFAULT_FREQ 440.0
#define DEFAULT_VOLUME 1.0

struct props {
	bool live;
	uint32_t wave;
	float freq;
	float volume;
};

static void reset_props(struct props *props)
{
	props->live = DEFAULT_LIVE;
	props->wave = DEFAULT_WAVE;
	props->freq = DEFAULT_FREQ;
	props->volume = DEFAULT_VOLUME;
}

#define MAX_BUFFERS	16
#define MAX_PORTS	1

struct buffer {
	uint32_t id;
	struct spa_buffer *outbuf;
	bool outstanding;
	struct spa_meta_header *h;
	struct spa_list link;
};

struct impl;

typedef void (*render_func_t) (struct impl *this, void *samples, size_t n_samples);

struct port {
	uint64_t info_all;
	struct spa_port_info info;
	struct spa_param_info params[5];

	struct spa_io_buffers *io;
	struct spa_io_sequence *io_control;

	bool have_format;
	struct spa_audio_info current_format;
	size_t bpf;
	render_func_t render_func;
	float accumulator;

	struct buffer buffers[MAX_BUFFERS];
	uint32_t n_buffers;

	struct spa_list empty;
};

struct impl {
	struct spa_handle handle;
	struct spa_node node;

	struct spa_log *log;
	struct spa_loop *data_loop;
	struct spa_system *data_system;

	uint32_t quantum_limit;

	uint64_t info_all;
	struct spa_node_info info;
	struct spa_param_info params[2];
	struct props props;
	struct spa_io_clock *clock;
	struct spa_io_position *position;

	struct spa_hook_list hooks;
	struct spa_callbacks callbacks;

	bool async;
	struct spa_source timer_source;
	struct itimerspec timerspec;

	bool started;
	uint64_t start_time;
	uint64_t elapsed_time;

	uint64_t sample_count;

	struct port port;
};

#define CHECK_PORT(this,d,p)  ((d) == SPA_DIRECTION_OUTPUT && (p) < MAX_PORTS)

static int impl_node_enum_params(void *object, int seq,
			uint32_t id, uint32_t start, uint32_t num,
			const struct spa_pod *filter)
{
	struct impl *this = object;
	struct spa_pod *param;
	struct spa_pod_builder b = { 0 };
	uint8_t buffer[1024];
	struct spa_result_node_params result;
	uint32_t count = 0;

	spa_return_val_if_fail(this != NULL, -EINVAL);
	spa_return_val_if_fail(num != 0, -EINVAL);

	result.id = id;
	result.next = start;
      next:
	result.index = result.next++;

	spa_pod_builder_init(&b, buffer, sizeof(buffer));

	switch (id) {
	case SPA_PARAM_PropInfo:
	{
		struct props *p = &this->props;
		struct spa_pod_frame f[2];

		switch (result.index) {
		case 0:
			param = spa_pod_builder_add_object(&b,
				SPA_TYPE_OBJECT_PropInfo, id,
				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_live),
				SPA_PROP_INFO_description, SPA_POD_String("Configure live mode of the source"),
				SPA_PROP_INFO_type, SPA_POD_Bool(p->live));
			break;
		case 1:
			spa_pod_builder_push_object(&b, &f[0], SPA_TYPE_OBJECT_PropInfo, id);
			spa_pod_builder_add(&b,
				SPA_PROP_INFO_id,     SPA_POD_Id(SPA_PROP_waveType),
				SPA_PROP_INFO_description,   SPA_POD_String("Select the waveform"),
				SPA_PROP_INFO_type,   SPA_POD_Int(p->wave),
				0);
			spa_pod_builder_prop(&b, SPA_PROP_INFO_labels, 0);
			spa_pod_builder_push_struct(&b, &f[1]);
			spa_pod_builder_int(&b, WAVE_SINE);
			spa_pod_builder_string(&b, "Sine wave");
			spa_pod_builder_int(&b, WAVE_SQUARE);
			spa_pod_builder_string(&b, "Square wave");
			spa_pod_builder_pop(&b, &f[1]);
			param = spa_pod_builder_pop(&b, &f[0]);
			break;
		case 2:
			param = spa_pod_builder_add_object(&b,
				SPA_TYPE_OBJECT_PropInfo, id,
				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_frequency),
				SPA_PROP_INFO_description, SPA_POD_String("Select the frequency"),
				SPA_PROP_INFO_type, SPA_POD_CHOICE_RANGE_Float(p->freq, 0.0, 50000000.0));
			break;
		case 3:
			param = spa_pod_builder_add_object(&b,
				SPA_TYPE_OBJECT_PropInfo, id,
				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_volume),
				SPA_PROP_INFO_description, SPA_POD_String("Select the volume"),
				SPA_PROP_INFO_type, SPA_POD_CHOICE_RANGE_Float(p->volume, 0.0, 10.0));
			break;
		default:
			return 0;
		}
		break;
	}
	case SPA_PARAM_Props:
	{
		struct props *p = &this->props;

		switch (result.index) {
		case 0:
			param = spa_pod_builder_add_object(&b,
				SPA_TYPE_OBJECT_Props, id,
				SPA_PROP_live,      SPA_POD_Bool(p->live),
				SPA_PROP_waveType,  SPA_POD_Int(p->wave),
				SPA_PROP_frequency, SPA_POD_Float(p->freq),
				SPA_PROP_volume,    SPA_POD_Float(p->volume));
			break;
		default:
			return 0;
		}
		break;
	}
	case SPA_PARAM_IO:
	{
		switch (result.index) {
		case 0:
			param = spa_pod_builder_add_object(&b,
					SPA_TYPE_OBJECT_ParamIO, id,
					SPA_PARAM_IO_id,	SPA_POD_Id(SPA_IO_Clock),
					SPA_PARAM_IO_size,	SPA_POD_Int(sizeof(struct spa_io_clock)));
			break;
		case 1:
			param = spa_pod_builder_add_object(&b,
					SPA_TYPE_OBJECT_ParamIO, id,
					SPA_PARAM_IO_id,	SPA_POD_Id(SPA_IO_Position),
					SPA_PARAM_IO_size,	SPA_POD_Int(sizeof(struct spa_io_position)));
			break;
		default:
			return 0;
		}
		break;
	}
	default:
		return -ENOENT;
	}

	if (spa_pod_filter(&b, &result.param, param, filter) < 0)
		goto next;

	spa_node_emit_result(&this->hooks, seq, 0, SPA_RESULT_TYPE_NODE_PARAMS, &result);

	if (++count != num)
		goto next;

	return 0;
}

static int impl_node_set_param(void *object, uint32_t id, uint32_t flags,
			       const struct spa_pod *param)
{
	struct impl *this = object;

	spa_return_val_if_fail(this != NULL, -EINVAL);

	if (id == SPA_PARAM_Props) {
		struct props *p = &this->props;
		struct port *port = &this->port;

		if (param == NULL) {
			reset_props(p);
			return 0;
		}
		spa_pod_parse_object(param,
			SPA_TYPE_OBJECT_Props, NULL,
			SPA_PROP_live,      SPA_POD_OPT_Bool(&p->live),
			SPA_PROP_waveType,  SPA_POD_OPT_Int(&p->wave),
			SPA_PROP_frequency, SPA_POD_OPT_Float(&p->freq),
			SPA_PROP_volume,    SPA_POD_OPT_Float(&p->volume));

		if (p->live)
			port->info.flags |= SPA_PORT_FLAG_LIVE;
		else
			port->info.flags &= ~SPA_PORT_FLAG_LIVE;
	}
	else
		return -ENOENT;

	return 0;
}

static int impl_node_set_io(void *object, uint32_t id, void *data, size_t size)
{
	struct impl *this = object;

	spa_return_val_if_fail(this != NULL, -EINVAL);

	switch (id) {
	case SPA_IO_Clock:
		if (size > 0 && size < sizeof(struct spa_io_clock))
			return -EINVAL;
		this->clock = data;
		break;
	case SPA_IO_Position:
		this->position = data;
		break;
	default:
		return -ENOENT;
	}
	return 0;
}

#include "render.c"

static void set_timer(struct impl *this, bool enabled)
{
	if (this->async || this->props.live) {
		if (enabled) {
			if (this->props.live) {
				uint64_t next_time = this->start_time + this->elapsed_time;
				this->timerspec.it_value.tv_sec = next_time / SPA_NSEC_PER_SEC;
				this->timerspec.it_value.tv_nsec = next_time % SPA_NSEC_PER_SEC;
			} else {
				this->timerspec.it_value.tv_sec = 0;
				this->timerspec.it_value.tv_nsec = 1;
			}
		} else {
			this->timerspec.it_value.tv_sec = 0;
			this->timerspec.it_value.tv_nsec = 0;
		}
		spa_system_timerfd_settime(this->data_system,
				this->timer_source.fd, SPA_FD_TIMER_ABSTIME, &this->timerspec, NULL);
	}
}

static int read_timer(struct impl *this)
{
	uint64_t expirations;
	int res = 0;

	if (this->async || this->props.live) {
		if ((res = spa_system_timerfd_read(this->data_system,
				this->timer_source.fd, &expirations)) < 0) {
			if (res != -EAGAIN)
				spa_log_error(this->log, "%p: timerfd error: %s",
						this, spa_strerror(res));
		}
	}
	return 0;
}

static void update_target(struct impl *this)
{
	if (this->position) {
		this->position->clock.duration = this->position->clock.target_duration;
		this->position->clock.rate = this->position->clock.target_rate;
	}
}

static int make_buffer(struct impl *this)
{
	struct buffer *b;
	struct port *port = &this->port;
	struct spa_io_buffers *io = port->io;
	uint32_t n_bytes, n_samples, maxsize;
	void *data;
	struct spa_data *d;
	uint32_t filled, avail;
	uint32_t index, offset, l0, l1;

	if (read_timer(this) < 0)
		return 0;

	if (spa_list_is_empty(&port->empty)) {
		set_timer(this, false);
		spa_log_error(this->log, "%p: out of buffers", this);
		return -EPIPE;
	}
	b = spa_list_first(&port->empty, struct buffer, link);
	spa_list_remove(&b->link);
	b->outstanding = true;

	d = b->outbuf->datas;
	maxsize = d[0].maxsize;
	data = d[0].data;

	n_bytes = maxsize;

	spa_log_trace(this->log, "%p: dequeue buffer %d %d %d", this, b->id,
		      maxsize, n_bytes);

	filled = 0;
	index = 0;
	avail = maxsize - filled;

	offset = index % maxsize;

	if (this->position && this->position->clock.duration) {
		n_bytes = SPA_MIN(avail, n_bytes);
		n_samples = this->position->clock.duration;
		if (n_samples * port->bpf < n_bytes)
			n_bytes = n_samples * port->bpf;
	} else {
		n_bytes = SPA_MIN(avail, n_bytes);
		n_samples = n_bytes / port->bpf;
	}
	l0 = SPA_MIN(n_bytes, maxsize - offset) / port->bpf;
	l1 = n_samples - l0;

	port->render_func(this, SPA_PTROFF(data, offset, void), l0);
	if (l1 > 0)
		port->render_func(this, data, l1);

	d[0].chunk->offset = index;
	d[0].chunk->size = n_bytes;
	d[0].chunk->stride = port->bpf;

	if (b->h) {
		b->h->seq = this->sample_count;
		b->h->pts = this->start_time + this->elapsed_time;
		b->h->dts_offset = 0;
	}

	this->sample_count += n_samples;
	this->elapsed_time = SAMPLES_TO_TIME(this, this->sample_count);
	set_timer(this, true);

	io->buffer_id = b->id;
	io->status = SPA_STATUS_HAVE_DATA;

	return io->status;
}

static void on_output(struct spa_source *source)
{
	struct impl *this = source->data;
	int res;

	update_target(this);

	res = make_buffer(this);

	if (res == SPA_STATUS_HAVE_DATA)
		spa_node_call_ready(&this->callbacks, res);
}

static int impl_node_send_command(void *object, const struct spa_command *command)
{
	struct impl *this = object;
	struct port *port;

	spa_return_val_if_fail(this != NULL, -EINVAL);
	spa_return_val_if_fail(command != NULL, -EINVAL);

	port = &this->port;

	switch (SPA_NODE_COMMAND_ID(command)) {
	case SPA_NODE_COMMAND_Start:
	{
		struct timespec now;

		if (!port->have_format)
			return -EIO;
		if (port->n_buffers == 0)
			return -EIO;

		if (this->started)
			return 0;

		clock_gettime(CLOCK_MONOTONIC, &now);
		if (this->props.live)
			this->start_time = SPA_TIMESPEC_TO_NSEC(&now);
		else
			this->start_time = 0;
		this->sample_count = 0;
		this->elapsed_time = 0;

		this->started = true;
		set_timer(this, true);
		break;
	}
	case SPA_NODE_COMMAND_Suspend:
	case SPA_NODE_COMMAND_Pause:
		if (!this->started)
			return 0;
		this->started = false;
		set_timer(this, false);
		break;

	default:
		return -ENOTSUP;
	}
	return 0;
}

static const struct spa_dict_item node_info_items[] = {
	{ SPA_KEY_MEDIA_CLASS, "Audio/Source" },
	{ SPA_KEY_NODE_DRIVER, "true" },
};

static void emit_node_info(struct impl *this, bool full)
{
	uint64_t old = full ? this->info.change_mask : 0;
	if (full)
		this->info.change_mask = this->info_all;
	if (this->info.change_mask) {
		this->info.props = &SPA_DICT_INIT_ARRAY(node_info_items);
		spa_node_emit_info(&this->hooks, &this->info);
		this->info.change_mask = old;
	}
}

static void emit_port_info(struct impl *this, struct port *port, bool full)
{
	uint64_t old = full ? port->info.change_mask : 0;
	if (full)
		port->info.change_mask = port->info_all;
	if (port->info.change_mask) {
		spa_node_emit_port_info(&this->hooks,
				SPA_DIRECTION_OUTPUT, 0, &port->info);
		port->info.change_mask = old;
	}
}

static int
impl_node_add_listener(void *object,
		struct spa_hook *listener,
		const struct spa_node_events *events,
		void *data)
{
	struct impl *this = object;
	struct spa_hook_list save;

	spa_return_val_if_fail(this != NULL, -EINVAL);

	spa_hook_list_isolate(&this->hooks, &save, listener, events, data);

	emit_node_info(this, true);
	emit_port_info(this, &this->port, true);

	spa_hook_list_join(&this->hooks, &save);

	return 0;
}

static int
impl_node_set_callbacks(void *object,
			const struct spa_node_callbacks *callbacks,
			void *data)
{
	struct impl *this = object;

	spa_return_val_if_fail(this != NULL, -EINVAL);

	this->callbacks = SPA_CALLBACKS_INIT(callbacks, data);

	return 0;
}

static int impl_node_add_port(void *object, enum spa_direction direction, uint32_t port_id,
		const struct spa_dict *props)
{
	return -ENOTSUP;
}

static int
impl_node_remove_port(void *object, enum spa_direction direction, uint32_t port_id)
{
	return -ENOTSUP;
}

static int
port_enum_formats(struct impl *this,
		  enum spa_direction direction, uint32_t port_id,
		  uint32_t index,
		  struct spa_pod **param,
		  struct spa_pod_builder *builder)
{
	switch (index) {
	case 0:
		*param = spa_pod_builder_add_object(builder,
			SPA_TYPE_OBJECT_Format, SPA_PARAM_EnumFormat,
			SPA_FORMAT_mediaType,      SPA_POD_Id(SPA_MEDIA_TYPE_audio),
			SPA_FORMAT_mediaSubtype,   SPA_POD_Id(SPA_MEDIA_SUBTYPE_raw),
			SPA_FORMAT_AUDIO_format,   SPA_POD_CHOICE_ENUM_Id(5,
							SPA_AUDIO_FORMAT_S16,
							SPA_AUDIO_FORMAT_S16,
							SPA_AUDIO_FORMAT_S32,
							SPA_AUDIO_FORMAT_F32,
							SPA_AUDIO_FORMAT_F64),
			SPA_FORMAT_AUDIO_rate,     SPA_POD_CHOICE_RANGE_Int(
							DEFAULT_RATE, 1, INT32_MAX),
			SPA_FORMAT_AUDIO_channels, SPA_POD_CHOICE_RANGE_Int(
							DEFAULT_CHANNELS, 1, INT32_MAX));
		break;
	default:
		return 0;
	}
	return 1;
}

static int
impl_node_port_enum_params(void *object, int seq,
			enum spa_direction direction, uint32_t port_id,
			uint32_t id, uint32_t start, uint32_t num,
			const struct spa_pod *filter)
{
	struct impl *this = object;
	struct port *port;
	struct spa_pod_builder b = { 0 };
	uint8_t buffer[1024];
	struct spa_pod *param;
	struct spa_result_node_params result;
	uint32_t count = 0;
	int res;

	spa_return_val_if_fail(this != NULL, -EINVAL);
	spa_return_val_if_fail(num != 0, -EINVAL);

	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);

	port = &this->port;

	result.id = id;
	result.next = start;
      next:
	result.index = result.next++;

	spa_pod_builder_init(&b, buffer, sizeof(buffer));

	switch (id) {
	case SPA_PARAM_EnumFormat:
		if ((res = port_enum_formats(this, direction, port_id,
						result.index, &param, &b)) <= 0)
			return res;
		break;

	case SPA_PARAM_Format:
		if (!port->have_format)
			return -EIO;
		if (result.index > 0)
			return 0;

		param = spa_format_audio_raw_build(&b, id, &port->current_format.info.raw);
		break;

	case SPA_PARAM_Buffers:
		if (!port->have_format)
			return -EIO;
		if (result.index > 0)
			return 0;

		param = spa_pod_builder_add_object(&b,
			SPA_TYPE_OBJECT_ParamBuffers, id,
			SPA_PARAM_BUFFERS_buffers, SPA_POD_CHOICE_RANGE_Int(1, 1, MAX_BUFFERS),
			SPA_PARAM_BUFFERS_blocks,  SPA_POD_Int(1),
			SPA_PARAM_BUFFERS_size,    SPA_POD_CHOICE_RANGE_Int(
							this->quantum_limit * port->bpf,
							16 * port->bpf,
							INT32_MAX),
			SPA_PARAM_BUFFERS_stride,  SPA_POD_Int(port->bpf));
		break;
	case SPA_PARAM_Meta:
		switch (result.index) {
		case 0:
			param = spa_pod_builder_add_object(&b,
				SPA_TYPE_OBJECT_ParamMeta, id,
				SPA_PARAM_META_type, SPA_POD_Id(SPA_META_Header),
				SPA_PARAM_META_size, SPA_POD_Int(sizeof(struct spa_meta_header)));
			break;
		default:
			return 0;
		}
		break;
	case SPA_PARAM_IO:
		switch (result.index) {
		case 0:
			param = spa_pod_builder_add_object(&b,
				SPA_TYPE_OBJECT_ParamIO, id,
				SPA_PARAM_IO_id,   SPA_POD_Id(SPA_IO_Buffers),
				SPA_PARAM_IO_size, SPA_POD_Int(sizeof(struct spa_io_buffers)));
			break;
		case 1:
			param = spa_pod_builder_add_object(&b,
				SPA_TYPE_OBJECT_ParamIO, id,
				SPA_PARAM_IO_id,   SPA_POD_Id(SPA_IO_Control),
				SPA_PARAM_IO_size, SPA_POD_Int(sizeof(struct spa_io_sequence)));
			break;
		default:
			return 0;
		}
		break;
	default:
		return -ENOENT;
	}

	if (spa_pod_filter(&b, &result.param, param, filter) < 0)
		goto next;

	spa_node_emit_result(&this->hooks, seq, 0, SPA_RESULT_TYPE_NODE_PARAMS, &result);

	if (++count != num)
		goto next;

	return 0;
}

static int clear_buffers(struct impl *this, struct port *port)
{
	if (port->n_buffers > 0) {
		spa_log_info(this->log, "%p: clear buffers", this);
		port->n_buffers = 0;
		spa_list_init(&port->empty);
		this->started = false;
		set_timer(this, false);
	}
	return 0;
}

static int
port_set_format(struct impl *this,
		enum spa_direction direction,
		uint32_t port_id,
		uint32_t flags,
		const struct spa_pod *format)
{
	int res;
	struct port *port = &this->port;

	if (format == NULL) {
		port->have_format = false;
		clear_buffers(this, port);
	} else {
		struct spa_audio_info info = { 0 };
		int idx;
		const size_t sizes[4] = { 2, 4, 4, 8 };

		if ((res = spa_format_parse(format, &info.media_type, &info.media_subtype)) < 0)
			return res;

		if (info.media_type != SPA_MEDIA_TYPE_audio ||
		    info.media_subtype != SPA_MEDIA_SUBTYPE_raw)
			return -EINVAL;

		if (spa_format_audio_raw_parse(format, &info.info.raw) < 0)
			return -EINVAL;

		if (info.info.raw.rate == 0 ||
		    info.info.raw.channels == 0)
			return -EINVAL;

		switch (info.info.raw.format) {
		case SPA_AUDIO_FORMAT_S16:
			idx = 0;
			break;
		case SPA_AUDIO_FORMAT_S32:
			idx = 1;
			break;
		case SPA_AUDIO_FORMAT_F32:
			idx = 2;
			break;
		case SPA_AUDIO_FORMAT_F64:
			idx = 3;
			break;
		default:
			return -EINVAL;
		}

		port->bpf = sizes[idx] * info.info.raw.channels;
		port->current_format = info;
		port->have_format = true;
		port->render_func = sine_funcs[idx];
	}

	port->info.change_mask |= SPA_PORT_CHANGE_MASK_PARAMS;
	if (port->have_format) {
		port->info.change_mask |= SPA_PORT_CHANGE_MASK_RATE;
		port->info.rate = SPA_FRACTION(1, port->current_format.info.raw.rate);
		port->params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_READWRITE);
		port->params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, SPA_PARAM_INFO_READ);
	} else {
		port->params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
		port->params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
	}
	emit_port_info(this, port, false);

	return 0;
}

static int
impl_node_port_set_param(void *object,
			 enum spa_direction direction, uint32_t port_id,
			 uint32_t id, uint32_t flags,
			 const struct spa_pod *param)
{
	struct impl *this = object;

	spa_return_val_if_fail(this != NULL, -EINVAL);

	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);

	if (id == SPA_PARAM_Format)
		return port_set_format(this, direction, port_id, flags, param);

	return -ENOENT;
}

static int
impl_node_port_use_buffers(void *object,
			   enum spa_direction direction,
			   uint32_t port_id,
			   uint32_t flags,
			   struct spa_buffer **buffers,
			   uint32_t n_buffers)
{
	struct impl *this = object;
	struct port *port;
	uint32_t i;

	spa_return_val_if_fail(this != NULL, -EINVAL);

	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);

	port = &this->port;

	clear_buffers(this, port);

	if (n_buffers > 0 && !port->have_format)
		return -EIO;
	if (n_buffers > MAX_BUFFERS)
		return -ENOSPC;

	for (i = 0; i < n_buffers; i++) {
		struct buffer *b;
		struct spa_data *d = buffers[i]->datas;

		b = &port->buffers[i];
		b->id = i;
		b->outbuf = buffers[i];
		b->outstanding = false;
		b->h = spa_buffer_find_meta_data(buffers[i], SPA_META_Header, sizeof(*b->h));

		if (d[0].data == NULL) {
			spa_log_error(this->log, "%p: invalid memory on buffer %p", this,
				      buffers[i]);
			return -EINVAL;
		}
		spa_list_append(&port->empty, &b->link);
	}
	port->n_buffers = n_buffers;

	return 0;
}

static int
impl_node_port_set_io(void *object,
		      enum spa_direction direction,
		      uint32_t port_id,
		      uint32_t id,
		      void *data, size_t size)
{
	struct impl *this = object;
	struct port *port;

	spa_return_val_if_fail(this != NULL, -EINVAL);

	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);

	port = &this->port;

	switch (id) {
	case SPA_IO_Buffers:
		port->io = data;
		break;
	case SPA_IO_Control:
		port->io_control = data;
		break;
	default:
		return -ENOENT;
	}
	return 0;
}

static inline void reuse_buffer(struct impl *this, struct port *port, uint32_t id)
{
	struct buffer *b = &port->buffers[id];
	spa_return_if_fail(b->outstanding);

	spa_log_trace(this->log, "%p: reuse buffer %d", this, id);

	b->outstanding = false;
	spa_list_append(&port->empty, &b->link);

	if (!this->props.live)
		set_timer(this, true);
}

static int impl_node_port_reuse_buffer(void *object, uint32_t port_id, uint32_t buffer_id)
{
	struct impl *this = object;
	struct port *port;

	spa_return_val_if_fail(this != NULL, -EINVAL);

	spa_return_val_if_fail(port_id == 0, -EINVAL);
	port = &this->port;
	spa_return_val_if_fail(buffer_id < port->n_buffers, -EINVAL);

	reuse_buffer(this, port, buffer_id);

	return 0;
}

static int process_control(struct impl *this, struct spa_pod_sequence *sequence)
{
	struct spa_pod_control *c;

	SPA_POD_SEQUENCE_FOREACH(sequence, c) {
		switch (c->type) {
		case SPA_CONTROL_Properties:
		{
			struct props *p = &this->props;
			spa_pod_parse_object(&c->value,
				SPA_TYPE_OBJECT_Props, NULL,
				SPA_PROP_frequency, SPA_POD_OPT_Float(&p->freq),
				SPA_PROP_volume,    SPA_POD_OPT_Float(&p->volume));
			break;
		}
		default:
			break;
                }
	}
	return 0;
}

static int impl_node_process(void *object)
{
	struct impl *this = object;
	struct port *port;
	struct spa_io_buffers *io;

	spa_return_val_if_fail(this != NULL, -EINVAL);

	port = &this->port;

	io = port->io;
	if ((io = port->io) == NULL)
		return -EIO;

	if (port->io_control)
		process_control(this, &port->io_control->sequence);

	if (io->status == SPA_STATUS_HAVE_DATA)
		return SPA_STATUS_HAVE_DATA;

	if (io->buffer_id < port->n_buffers) {
		reuse_buffer(this, port, io->buffer_id);
		io->buffer_id = SPA_ID_INVALID;
	}

	if (!this->props.live)
		return make_buffer(this);
	else
		return SPA_STATUS_OK;
}

static const struct spa_node_methods impl_node = {
	SPA_VERSION_NODE_METHODS,
	.add_listener = impl_node_add_listener,
	.set_callbacks = impl_node_set_callbacks,
	.enum_params = impl_node_enum_params,
	.set_param = impl_node_set_param,
	.set_io = impl_node_set_io,
	.send_command = impl_node_send_command,
	.add_port = impl_node_add_port,
	.remove_port = impl_node_remove_port,
	.port_enum_params = impl_node_port_enum_params,
	.port_set_param = impl_node_port_set_param,
	.port_use_buffers = impl_node_port_use_buffers,
	.port_set_io = impl_node_port_set_io,
	.port_reuse_buffer = impl_node_port_reuse_buffer,
	.process = impl_node_process,
};

static int impl_get_interface(struct spa_handle *handle, const char *type, void **interface)
{
	struct impl *this;

	spa_return_val_if_fail(handle != NULL, -EINVAL);
	spa_return_val_if_fail(interface != NULL, -EINVAL);

	this = (struct impl *) handle;

	if (spa_streq(type, SPA_TYPE_INTERFACE_Node))
		*interface = &this->node;
	else
		return -ENOENT;

	return 0;
}

static int do_remove_timer(struct spa_loop *loop, bool async, uint32_t seq, const void *data, size_t size, void *user_data)
{
	struct impl *this = user_data;
	spa_loop_remove_source(this->data_loop, &this->timer_source);
	return 0;
}

static int impl_clear(struct spa_handle *handle)
{
	struct impl *this;

	spa_return_val_if_fail(handle != NULL, -EINVAL);

	this = (struct impl *) handle;

	if (this->data_loop)
		spa_loop_locked(this->data_loop, do_remove_timer, 0, NULL, 0, this);
	spa_system_close(this->data_system, this->timer_source.fd);

	return 0;
}

static size_t
impl_get_size(const struct spa_handle_factory *factory,
	      const struct spa_dict *params)
{
	return sizeof(struct impl);
}

static int
impl_init(const struct spa_handle_factory *factory,
	  struct spa_handle *handle,
	  const struct spa_dict *info,
	  const struct spa_support *support,
	  uint32_t n_support)
{
	struct impl *this;
	struct port *port;
	uint32_t i;

	spa_return_val_if_fail(factory != NULL, -EINVAL);
	spa_return_val_if_fail(handle != NULL, -EINVAL);

	handle->get_interface = impl_get_interface;
	handle->clear = impl_clear;

	this = (struct impl *) handle;

	this->log = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_Log);

	this->data_loop = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_DataLoop);
	if (this->data_loop == NULL) {
		spa_log_error(this->log, "%p: could not find a data loop", this);
		return -EINVAL;
	}

	this->data_system = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_DataSystem);
	if (this->data_system == NULL) {
		spa_log_error(this->log, "%p: could not find a data system", this);
		return -EINVAL;
	}

	for (i = 0; info && i < info->n_items; i++) {
		const char *k = info->items[i].key;
		const char *s = info->items[i].value;
		if (spa_streq(k, "clock.quantum-limit"))
			spa_atou32(s, &this->quantum_limit, 0);
	}
	spa_hook_list_init(&this->hooks);

	this->node.iface = SPA_INTERFACE_INIT(
			SPA_TYPE_INTERFACE_Node,
			SPA_VERSION_NODE,
			&impl_node, this);

	this->info_all |= SPA_NODE_CHANGE_MASK_FLAGS |
			SPA_NODE_CHANGE_MASK_PROPS |
			SPA_NODE_CHANGE_MASK_PARAMS;
	this->info = SPA_NODE_INFO_INIT();
	this->info.max_output_ports = 1;
	this->info.flags = SPA_NODE_FLAG_RT;
	this->params[0] = SPA_PARAM_INFO(SPA_PARAM_PropInfo, SPA_PARAM_INFO_READ);
	this->params[1] = SPA_PARAM_INFO(SPA_PARAM_Props, SPA_PARAM_INFO_READWRITE);
	this->info.params = this->params;
	this->info.n_params = 2;
	reset_props(&this->props);

	this->timer_source.func = on_output;
	this->timer_source.data = this;
	this->timer_source.fd = spa_system_timerfd_create(this->data_system,
			CLOCK_MONOTONIC, SPA_FD_CLOEXEC | SPA_FD_NONBLOCK);
	this->timer_source.mask = SPA_IO_IN;
	this->timer_source.rmask = 0;
	this->timerspec.it_value.tv_sec = 0;
	this->timerspec.it_value.tv_nsec = 0;
	this->timerspec.it_interval.tv_sec = 0;
	this->timerspec.it_interval.tv_nsec = 0;

	if (this->data_loop)
		spa_loop_add_source(this->data_loop, &this->timer_source);

	port = &this->port;
	port->info_all = SPA_PORT_CHANGE_MASK_FLAGS |
			SPA_PORT_CHANGE_MASK_PARAMS;
	port->info = SPA_PORT_INFO_INIT();
	port->info.flags = SPA_PORT_FLAG_NO_REF;
	if (this->props.live)
		port->info.flags |= SPA_PORT_FLAG_LIVE;
	port->params[0] = SPA_PARAM_INFO(SPA_PARAM_EnumFormat, SPA_PARAM_INFO_READ);
	port->params[1] = SPA_PARAM_INFO(SPA_PARAM_Meta, SPA_PARAM_INFO_READ);
	port->params[2] = SPA_PARAM_INFO(SPA_PARAM_IO, SPA_PARAM_INFO_READ);
	port->params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
	port->params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
	port->info.params = port->params;
	port->info.n_params = 5;
	spa_list_init(&port->empty);

	spa_log_info(this->log, "%p: initialized", this);

	return 0;
}

static const struct spa_interface_info impl_interfaces[] = {
	{SPA_TYPE_INTERFACE_Node,},
};

static int
impl_enum_interface_info(const struct spa_handle_factory *factory,
			 const struct spa_interface_info **info,
			 uint32_t *index)
{
	spa_return_val_if_fail(factory != NULL, -EINVAL);
	spa_return_val_if_fail(info != NULL, -EINVAL);
	spa_return_val_if_fail(index != NULL, -EINVAL);

	switch (*index) {
	case 0:
		*info = &impl_interfaces[*index];
		break;
	default:
		return 0;
	}
	(*index)++;

	return 1;
}

static const struct spa_dict_item info_items[] = {
	{ SPA_KEY_FACTORY_AUTHOR, "Wim Taymans <wim.taymans@gmail.com>" },
	{ SPA_KEY_FACTORY_DESCRIPTION, "Generate an audio test pattern" },
};

static const struct spa_dict info = SPA_DICT_INIT_ARRAY(info_items);

const struct spa_handle_factory spa_audiotestsrc_factory = {
	SPA_VERSION_HANDLE_FACTORY,
	"audiotestsrc",
	&info,
	impl_get_size,
	impl_init,
	impl_enum_interface_info,
};