/* 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/loop.h>
#include <spa/utils/list.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/param/param.h>
#include <spa/param/format.h>
#include <spa/pod/parser.h>
#include <spa/pod/filter.h>

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

struct props {
	bool live;
	uint32_t pattern;
};

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

	struct spa_io_buffers *io;

	bool have_format;
	uint8_t format_buffer[1024];

	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;

	uint64_t info_all;
	struct spa_node_info info;
	struct spa_param_info params[1];
	struct props props;

	struct spa_hook_list hooks;
	struct spa_callbacks callbacks;

	struct spa_source timer_source;
	struct itimerspec timerspec;

	bool started;
	uint64_t start_time;
	uint64_t elapsed_time;

	uint64_t buffer_count;
	bool underrun;

	struct port port;
};

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

#define DEFAULT_LIVE false
#define DEFAULT_PATTERN 0

static void reset_props(struct impl *this, struct props *props)
{
	props->live = DEFAULT_LIVE;
	props->pattern = DEFAULT_PATTERN;
}

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_builder b = { 0 };
	uint8_t buffer[1024];
	struct spa_pod *param;
	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_Props:
	{
		struct props *p = &this->props;

		if (result.index > 0)
			return 0;

		param = spa_pod_builder_add_object(&b,
			SPA_TYPE_OBJECT_Props, id,
			SPA_PROP_live,        SPA_POD_Bool(p->live),
			SPA_PROP_patternType, SPA_POD_CHOICE_ENUM_Id(2, p->pattern, p->pattern));
		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_io(void *object, uint32_t id, void *data, size_t size)
{
	return -ENOTSUP;
}

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);

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

		if (param == NULL) {
			reset_props(this, p);
			return 0;
		}
		spa_pod_parse_object(param,
			SPA_TYPE_OBJECT_Props, NULL,
			SPA_PROP_live,        SPA_POD_OPT_Bool(&p->live),
			SPA_PROP_patternType, SPA_POD_OPT_Id(&p->pattern));

		if (p->live)
			port->info.flags |= SPA_PORT_FLAG_LIVE;
		else
			port->info.flags &= ~SPA_PORT_FLAG_LIVE;
		break;
	}
	default:
		return -ENOENT;
	}
	return 0;
}

static int fill_buffer(struct impl *this, struct buffer *b)
{
	return 0;
}

static void set_timer(struct impl *this, bool enabled)
{
	if (this->callbacks.funcs || 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 inline int read_timer(struct impl *this)
{
	uint64_t expirations;
	int res = 0;

	if (this->callbacks.funcs || 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 res;
}

static int make_buffer(struct impl *this)
{
	struct buffer *b;
	struct port *port = &this->port;
	struct spa_io_buffers *io = port->io;
	int n_bytes;

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

	if (spa_list_is_empty(&port->empty)) {
		set_timer(this, false);
		this->underrun = true;
		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;

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

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

	fill_buffer(this, b);

	b->outbuf->datas[0].chunk->offset = 0;
	b->outbuf->datas[0].chunk->size = n_bytes;
	b->outbuf->datas[0].chunk->stride = n_bytes;

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

	this->buffer_count++;
	this->elapsed_time = this->buffer_count;
	set_timer(this, true);

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

	return SPA_STATUS_HAVE_DATA;
}

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

	res = make_buffer(this);

	if (res == SPA_STATUS_HAVE_DATA && this->callbacks.funcs)
		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->buffer_count = 0;
		this->elapsed_time = 0;

		this->started = true;
		set_timer(this, true);
		break;
	}
	case SPA_NODE_COMMAND_Pause:
		if (!port->have_format)
			return -EIO;
		if (port->n_buffers == 0)
			return -EIO;

		if (!this->started)
			return 0;

		this->started = false;
		set_timer(this, false);
		break;
	default:
		return -ENOTSUP;
	}
	return 0;
}

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) {
		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);

	if (this->data_loop == NULL && callbacks != NULL) {
		spa_log_error(this->log, "a data_loop is needed for async operation");
		return -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, struct port *port,
			     uint32_t index,
			     const struct spa_pod *filter,
			     struct spa_pod **param,
			     struct spa_pod_builder *builder)
{
	return 0;
}

static int port_get_format(struct impl *this, struct port *port,
			   uint32_t index,
			   const struct spa_pod *filter,
			   struct spa_pod **param,
			   struct spa_pod_builder *builder)
{
	if (!port->have_format)
		return -EIO;
	if (index > 0)
		return 0;

	*param = SPA_PTROFF(port->format_buffer, 0, struct spa_pod);

	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(node, 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, port,
					result.index, filter, &param, &b)) <= 0)
			return res;
		break;
	case SPA_PARAM_Format:
		if ((res = port_get_format(this, port,
					result.index, filter, &param, &b)) <= 0)
			return res;
		break;
	case SPA_PARAM_Buffers:
		switch (result.index) {
		case 0:
			param = spa_pod_builder_add_object(&b,
				SPA_TYPE_OBJECT_ParamBuffers, id,
				SPA_PARAM_BUFFERS_buffers, SPA_POD_CHOICE_RANGE_Int(32, 2, 32),
				SPA_PARAM_BUFFERS_blocks,  SPA_POD_Int(1),
				SPA_PARAM_BUFFERS_size,    SPA_POD_Int(128),
				SPA_PARAM_BUFFERS_stride,  SPA_POD_Int(1));
			break;
		default:
			return 0;
		}
		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;
	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_debug(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, struct port *port,
			   uint32_t flags,
			   const struct spa_pod *format)
{
	if (format == NULL) {
		port->have_format = false;
		clear_buffers(this, port);
	} else {
		if (SPA_POD_SIZE(format) > sizeof(port->format_buffer))
			return -ENOSPC;
		memcpy(port->format_buffer, format, SPA_POD_SIZE(format));
		port->have_format = true;
	}
	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;
	struct port *port;

	spa_return_val_if_fail(this != NULL, -EINVAL);
	spa_return_val_if_fail(CHECK_PORT(node, direction, port_id), -EINVAL);
	port = &this->port;

	if (id == SPA_PARAM_Format) {
		return port_set_format(this, port, flags, param);
	}
	else
		return -ENOENT;
}

static int
impl_node_port_use_buffers(void *object,
		enum spa_direction direction, uint32_t flags,
		uint32_t port_id,
		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]);
		}
		spa_list_append(&port->empty, &b->link);
	}
	port->n_buffers = n_buffers;
	this->underrun = false;

	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;

	if (id == SPA_IO_Buffers)
		port->io = data;
	else
		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->underrun) {
		set_timer(this, true);
		this->underrun = false;
	}
}

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

	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->callbacks.funcs == NULL)
		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_invoke(this->data_loop, do_remove_timer, 0, NULL, 0, true, 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;

	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);
	this->data_system = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_DataSystem);

	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_PARAMS;
	this->info = SPA_NODE_INFO_INIT();
	this->info.max_input_ports = 0;
	this->info.max_output_ports = 1;
	this->info.flags = SPA_NODE_FLAG_RT;
	this->params[0] = SPA_PARAM_INFO(SPA_PARAM_Props, SPA_PARAM_INFO_READWRITE);
	this->info.params = this->params;
	this->info.n_params = 1;
	reset_props(this, &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_Meta, SPA_PARAM_INFO_READ);
	port->params[1] = SPA_PARAM_INFO(SPA_PARAM_IO, 0);
	port->params[2] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
	port->params[3] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
	port->info.params = port->params;
	port->info.n_params = 4;

	spa_list_init(&port->empty);

	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;
}

const struct spa_handle_factory spa_fakesrc_factory = {
	SPA_VERSION_HANDLE_FACTORY,
	"fakesrc",
	NULL,
	impl_get_size,
	impl_init,
	impl_enum_interface_info,
};
