/* Simple Plugin API
 * Copyright (C) 2016 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 <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dlfcn.h>
#include <errno.h>
#include <poll.h>

#include <spa/support/log-impl.h>
#include <spa/support/loop.h>
#include <spa/support/plugin.h>
#include <spa/monitor/monitor.h>

#include <spa/debug/dict.h>
#include <spa/debug/pod.h>

static SPA_LOG_IMPL(default_log);

struct data {
	struct spa_log *log;
	struct spa_loop main_loop;

	struct spa_support support[3];
	uint32_t n_support;

	unsigned int n_sources;
	struct spa_source sources[16];

	bool rebuild_fds;
	struct pollfd fds[16];
	unsigned int n_fds;
};


static void inspect_item(struct data *data, struct spa_pod *item)
{
	spa_debug_pod(0, spa_type_monitor, item);
}

static void on_monitor_event(void *_data, struct spa_event *event)
{
	struct data *data = _data;

	switch (SPA_EVENT_TYPE(event)) {
	case SPA_ID_EVENT_MONITOR_Added:
		fprintf(stderr, "added:\n");
		inspect_item(data, SPA_POD_CONTENTS(struct spa_event, event));
		break;
	case SPA_ID_EVENT_MONITOR_Removed:
		fprintf(stderr, "removed:\n");
		inspect_item(data, SPA_POD_CONTENTS(struct spa_event, event));
		break;
	case SPA_ID_EVENT_MONITOR_Changed:
		fprintf(stderr, "changed:\n");
		inspect_item(data, SPA_POD_CONTENTS(struct spa_event, event));
		break;
	}
}

static int do_add_source(struct spa_loop *loop, struct spa_source *source)
{
	struct data *data = SPA_CONTAINER_OF(loop, struct data, main_loop);

	data->sources[data->n_sources] = *source;
	data->n_sources++;
	data->rebuild_fds = true;

	return 0;
}

static int do_update_source(struct spa_source *source)
{
	return 0;
}

static void do_remove_source(struct spa_source *source)
{
}

static const struct spa_monitor_callbacks impl_callbacks = {
	SPA_VERSION_MONITOR_CALLBACKS,
	.event = on_monitor_event,
};

static void handle_monitor(struct data *data, struct spa_monitor *monitor)
{
	int res;
	uint32_t index;

	if (monitor->info)
		spa_debug_dict(0, monitor->info);

	for (index = 0;;) {
		struct spa_pod *item;
		uint8_t buffer[4096];
		struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));

		if ((res = spa_monitor_enum_items(monitor, &index, &item, &b)) <= 0) {
			if (res != 0)
				printf("spa_monitor_enum_items: %s\n", spa_strerror(res));
			break;
		}
		inspect_item(data, item);
	}
	spa_monitor_set_callbacks(monitor, &impl_callbacks, data);

	while (true) {
		int i, r;

		/* rebuild */
		if (data->rebuild_fds) {
			for (i = 0; i < data->n_sources; i++) {
				struct spa_source *p = &data->sources[i];
				data->fds[i].fd = p->fd;
				data->fds[i].events = p->mask;
			}
			data->n_fds = data->n_sources;
			data->rebuild_fds = false;
		}

		r = poll((struct pollfd *) data->fds, data->n_fds, -1);
		if (r < 0) {
			if (errno == EINTR)
				continue;
			break;
		}
		if (r == 0) {
			fprintf(stderr, "monitor %p: select timeout", monitor);
			break;
		}

		/* after */
		for (i = 0; i < data->n_sources; i++) {
			struct spa_source *p = &data->sources[i];
			p->func(p);
		}
	}
}

int main(int argc, char *argv[])
{
	struct data data = { 0 };
	int res;
	void *handle;
	spa_handle_factory_enum_func_t enum_func;
	uint32_t fidx;

	data.log = &default_log.log;
	data.main_loop.version = SPA_VERSION_LOOP;
	data.main_loop.add_source = do_add_source;
	data.main_loop.update_source = do_update_source;
	data.main_loop.remove_source = do_remove_source;

	data.support[1] = SPA_SUPPORT_INIT(SPA_ID_INTERFACE_Log, data.log);
	data.support[2] = SPA_SUPPORT_INIT(SPA_ID_INTERFACE_MainLoop, &data.main_loop);
	data.n_support = 3;

	if (argc < 2) {
		printf("usage: %s <plugin.so>\n", argv[0]);
		return -1;
	}

	if ((handle = dlopen(argv[1], RTLD_NOW)) == NULL) {
		printf("can't load %s\n", argv[1]);
		return -1;
	}
	if ((enum_func = dlsym(handle, SPA_HANDLE_FACTORY_ENUM_FUNC_NAME)) == NULL) {
		printf("can't find function\n");
		return -1;
	}

	for (fidx = 0;;) {
		const struct spa_handle_factory *factory;
		uint32_t iidx;

		if ((res = enum_func(&factory, &fidx)) <= 0) {
			if (res != 0)
				printf("can't enumerate factories: %d\n", res);
			break;
		}

		for (iidx = 0;;) {
			const struct spa_interface_info *info;

			if ((res =
			     spa_handle_factory_enum_interface_info(factory, &info, &iidx)) <= 0) {
				if (res != 0)
					printf("can't enumerate interfaces: %d\n", res);
				break;
			}

			if (info->type == SPA_ID_INTERFACE_Monitor) {
				struct spa_handle *handle;
				void *interface;

				handle = calloc(1, spa_handle_factory_get_size(factory, NULL));
				if ((res =
				     spa_handle_factory_init(factory, handle, NULL, data.support,
							     data.n_support)) < 0) {
					printf("can't make factory instance: %s\n", strerror(res));
					continue;
				}

				if ((res =
				     spa_handle_get_interface(handle, SPA_ID_INTERFACE_Monitor,
							      &interface)) < 0) {
					printf("can't get interface: %s\n", strerror(res));
					continue;
				}
				handle_monitor(&data, interface);
			}
		}
	}

	return 0;
}