/*-
 *   BSD LICENSE
 *
 *   Copyright (c) Intel Corporation.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "spdk/stdinc.h"

#include "nvmf_tgt.h"

#include "spdk/bdev.h"
#include "spdk/event.h"
#include "spdk/log.h"
#include "spdk/nvme.h"
#include "spdk/util.h"

struct nvmf_tgt_poll_group {
	struct spdk_nvmf_poll_group *group;
	struct spdk_poller *poller;
};

struct nvmf_tgt g_tgt = {};

static struct nvmf_tgt_poll_group *g_poll_groups = NULL;
static size_t g_num_poll_groups = 0;
static size_t g_active_poll_groups = 0;

static struct spdk_poller *g_acceptor_poller = NULL;

static TAILQ_HEAD(, nvmf_tgt_subsystem) g_subsystems = TAILQ_HEAD_INITIALIZER(g_subsystems);
static bool g_subsystems_shutdown;

static void nvmf_tgt_advance_state(void *arg1, void *arg2);

static void
subsystem_delete_event(void *arg1, void *arg2)
{
	struct nvmf_tgt_subsystem *app_subsys = arg1;
	struct spdk_nvmf_subsystem *subsystem = app_subsys->subsystem;

	TAILQ_REMOVE(&g_subsystems, app_subsys, tailq);
	free(app_subsys);

	spdk_nvmf_delete_subsystem(subsystem);

	if (g_subsystems_shutdown && TAILQ_EMPTY(&g_subsystems)) {
		g_tgt.state = NVMF_TGT_FINI_FREE_RESOURCES;
		nvmf_tgt_advance_state(NULL, NULL);
	}
}

static void
subsystem_unregister_poller(void *arg1, void *arg2)
{
	struct nvmf_tgt_subsystem *app_subsys = arg1;
	struct spdk_event *event = arg2;

	spdk_poller_unregister(&app_subsys->poller);

	spdk_event_call(event);
}

static void
nvmf_tgt_delete_subsystem(struct nvmf_tgt_subsystem *app_subsys)
{
	struct spdk_event *event1, *event2;

	event2 = spdk_event_allocate(spdk_env_get_current_core(), subsystem_delete_event,
				     app_subsys, NULL);
	event1 = spdk_event_allocate(app_subsys->lcore, subsystem_unregister_poller, app_subsys, event2);

	spdk_event_call(event1);
}

static void
spdk_nvmf_shutdown_cb(void)
{
	fprintf(stdout, "\n=========================\n");
	fprintf(stdout, "   NVMF shutdown signal\n");
	fprintf(stdout, "=========================\n");

	g_tgt.state = NVMF_TGT_FINI_STOP_ACCEPTOR;
	nvmf_tgt_advance_state(NULL, NULL);
}

static void
subsystem_poll(void *arg)
{
	struct nvmf_tgt_subsystem *app_subsys = arg;

	spdk_nvmf_subsystem_poll(app_subsys->subsystem);
}

static void
_nvmf_tgt_start_subsystem(void *arg1, void *arg2)
{
	struct nvmf_tgt_subsystem *app_subsys = arg1;
	struct spdk_nvmf_subsystem *subsystem = app_subsys->subsystem;

	spdk_nvmf_subsystem_start(subsystem);

	spdk_poller_register(&app_subsys->poller, subsystem_poll, app_subsys, 0);
}

void
nvmf_tgt_start_subsystem(struct nvmf_tgt_subsystem *app_subsys)
{
	struct spdk_event *event;

	event = spdk_event_allocate(app_subsys->lcore, _nvmf_tgt_start_subsystem,
				    app_subsys, NULL);
	spdk_event_call(event);
}

struct nvmf_tgt_subsystem *
nvmf_tgt_create_subsystem(const char *name, enum spdk_nvmf_subtype subtype, uint32_t num_ns,
			  uint32_t lcore)
{
	struct spdk_nvmf_subsystem *subsystem;
	struct nvmf_tgt_subsystem *app_subsys;

	if (spdk_nvmf_tgt_find_subsystem(g_tgt.tgt, name)) {
		SPDK_ERRLOG("Subsystem already exist\n");
		return NULL;
	}

	app_subsys = calloc(1, sizeof(*app_subsys));
	if (app_subsys == NULL) {
		SPDK_ERRLOG("Subsystem allocation failed\n");
		return NULL;
	}

	subsystem = spdk_nvmf_create_subsystem(g_tgt.tgt, name, subtype, num_ns);
	if (subsystem == NULL) {
		SPDK_ERRLOG("Subsystem creation failed\n");
		free(app_subsys);
		return NULL;
	}

	app_subsys->subsystem = subsystem;
	app_subsys->lcore = lcore;

	SPDK_NOTICELOG("allocated subsystem %s on lcore %u on socket %u\n", name, lcore,
		       spdk_env_get_socket_id(lcore));

	TAILQ_INSERT_TAIL(&g_subsystems, app_subsys, tailq);

	return app_subsys;
}

struct nvmf_tgt_subsystem *
nvmf_tgt_subsystem_first(void)
{
	return TAILQ_FIRST(&g_subsystems);
}

struct nvmf_tgt_subsystem *
nvmf_tgt_subsystem_next(struct nvmf_tgt_subsystem *subsystem)
{
	return TAILQ_NEXT(subsystem, tailq);
}

int
nvmf_tgt_shutdown_subsystem_by_nqn(const char *nqn)
{
	struct nvmf_tgt_subsystem *tgt_subsystem, *subsys_tmp;

	TAILQ_FOREACH_SAFE(tgt_subsystem, &g_subsystems, tailq, subsys_tmp) {
		if (strcmp(spdk_nvmf_subsystem_get_nqn(tgt_subsystem->subsystem), nqn) == 0) {
			nvmf_tgt_delete_subsystem(tgt_subsystem);
			return 0;
		}
	}
	return -1;
}

static void
acceptor_poll(void *arg)
{
	struct spdk_nvmf_tgt *tgt = arg;

	spdk_nvmf_tgt_accept(tgt);
}

static void
nvmf_tgt_poll_group_poll(void *arg)
{
	struct nvmf_tgt_poll_group *app_poll_group = arg;

	spdk_nvmf_poll_group_poll(app_poll_group->group);
}

static void
nvmf_tgt_destroy_poll_group_done(void *arg1, void *arg2)
{
	g_tgt.state = NVMF_TGT_FINI_DESTROY_POLL_GROUP_DONE;
	nvmf_tgt_advance_state(NULL, NULL);
}

static void
nvmf_tgt_destroy_poll_group(void *arg1, void *arg2)
{
	struct nvmf_tgt_poll_group *pg;
	struct spdk_event *event = arg1;

	assert(g_tgt.core == spdk_env_get_current_core());

	pg = &g_poll_groups[g_tgt.core];
	assert(pg != NULL);

	spdk_poller_unregister(&pg->poller);

	spdk_nvmf_poll_group_destroy(pg->group);
	pg->group = NULL;

	assert(g_active_poll_groups > 0);
	g_active_poll_groups--;

	spdk_event_call(event);
}

static void
nvmf_tgt_create_poll_group_done(void *arg1, void *arg2)
{
	struct nvmf_tgt_poll_group *pg;

	pg = &g_poll_groups[g_tgt.core];
	if (pg->group == NULL) {
		g_tgt.state = NVMF_TGT_ERROR;
	} else {
		g_tgt.state = NVMF_TGT_INIT_CREATE_POLL_GROUP_DONE;
	}

	nvmf_tgt_advance_state(NULL, NULL);
}

static void
nvmf_tgt_create_poll_group(void *arg1, void *arg2)
{
	struct nvmf_tgt_poll_group *pg;
	struct spdk_event *event = arg1;

	assert(g_tgt.core == spdk_env_get_current_core());

	pg = &g_poll_groups[g_tgt.core];
	pg->group = spdk_nvmf_poll_group_create(g_tgt.tgt);
	if (pg->group == NULL) {
		SPDK_ERRLOG("Failed to create poll group for core %u\n", g_tgt.core);
	}

	spdk_poller_register(&pg->poller, nvmf_tgt_poll_group_poll, pg, 0);
	g_active_poll_groups++;

	spdk_event_call(event);
}

static void
nvmf_tgt_advance_state(void *arg1, void *arg2)
{
	enum nvmf_tgt_state prev_state;
	int rc = -1;

	do {
		prev_state = g_tgt.state;

		switch (g_tgt.state) {
		case NVMF_TGT_INIT_NONE: {
			uint32_t core;

			g_tgt.state = NVMF_TGT_INIT_PARSE_CONFIG;
			g_tgt.core = spdk_env_get_first_core();

			/* Find the maximum core number */
			SPDK_ENV_FOREACH_CORE(core) {
				g_num_poll_groups = spdk_max(g_num_poll_groups, core + 1);
			}
			assert(g_num_poll_groups > 0);

			g_poll_groups = calloc(g_num_poll_groups, sizeof(*g_poll_groups));
			if (g_poll_groups == NULL) {
				g_tgt.state = NVMF_TGT_ERROR;
				rc = -ENOMEM;
				break;
			}
			break;
		}
		case NVMF_TGT_INIT_PARSE_CONFIG:
			rc = spdk_nvmf_parse_conf();
			if (rc < 0) {
				SPDK_ERRLOG("spdk_nvmf_parse_conf() failed\n");
				g_tgt.state = NVMF_TGT_ERROR;
				rc = -EINVAL;
				break;
			}
			g_tgt.state = NVMF_TGT_INIT_CREATE_POLL_GROUP;
			break;
		case NVMF_TGT_INIT_CREATE_POLL_GROUP: {
			struct spdk_event *event, *return_event;

			/* Send an event to the poller core, create an event, and event back to this core. */
			return_event = spdk_event_allocate(spdk_env_get_current_core(), nvmf_tgt_create_poll_group_done,
							   NULL, NULL);
			event = spdk_event_allocate(g_tgt.core, nvmf_tgt_create_poll_group,
						    return_event, NULL);
			spdk_event_call(event);
			break;
		}
		case NVMF_TGT_INIT_CREATE_POLL_GROUP_DONE: {
			g_tgt.core = spdk_env_get_next_core(g_tgt.core);
			if (g_tgt.core != UINT32_MAX) {
				g_tgt.state = NVMF_TGT_INIT_CREATE_POLL_GROUP;
			} else {
				g_tgt.state = NVMF_TGT_INIT_START_ACCEPTOR;
			}
			break;
		}
		case NVMF_TGT_INIT_START_ACCEPTOR:
			spdk_poller_register(&g_acceptor_poller, acceptor_poll, g_tgt.tgt,
					     g_spdk_nvmf_tgt_conf.acceptor_poll_rate);
			SPDK_NOTICELOG("Acceptor running\n");
			g_tgt.state = NVMF_TGT_RUNNING;
			break;
		case NVMF_TGT_RUNNING:
			if (getenv("MEMZONE_DUMP") != NULL) {
				spdk_memzone_dump(stdout);
				fflush(stdout);
			}
			break;
		case NVMF_TGT_FINI_STOP_ACCEPTOR: {
			spdk_poller_unregister(&g_acceptor_poller);
			g_tgt.core = spdk_env_get_first_core();
			g_tgt.state = NVMF_TGT_FINI_DESTROY_POLL_GROUP;
			break;
		}
		case NVMF_TGT_FINI_DESTROY_POLL_GROUP: {
			struct spdk_event *event, *return_event;

			/* Send an event to the poller core, destroy the poll group, and event back to this core. */
			return_event = spdk_event_allocate(spdk_env_get_current_core(), nvmf_tgt_destroy_poll_group_done,
							   NULL, NULL);
			event = spdk_event_allocate(g_tgt.core, nvmf_tgt_destroy_poll_group,
						    return_event, NULL);
			spdk_event_call(event);
			break;
		}
		case NVMF_TGT_FINI_DESTROY_POLL_GROUP_DONE:
			g_tgt.core = spdk_env_get_next_core(g_tgt.core);
			if (g_tgt.core != UINT32_MAX) {
				g_tgt.state = NVMF_TGT_FINI_DESTROY_POLL_GROUP;
			} else {
				assert(g_active_poll_groups == 0);
				g_tgt.state = NVMF_TGT_FINI_SHUTDOWN_SUBSYSTEMS;
			}
			break;
		case NVMF_TGT_FINI_SHUTDOWN_SUBSYSTEMS: {
			struct nvmf_tgt_subsystem *app_subsys, *tmp;

			g_subsystems_shutdown = true;
			TAILQ_FOREACH_SAFE(app_subsys, &g_subsystems, tailq, tmp) {
				nvmf_tgt_delete_subsystem(app_subsys);
			}
			break;
		}
		case NVMF_TGT_FINI_FREE_RESOURCES:
			spdk_nvmf_tgt_destroy(g_tgt.tgt);
			g_tgt.state = NVMF_TGT_STOPPED;
			break;
		case NVMF_TGT_STOPPED:
			spdk_app_stop(0);
			return;
		case NVMF_TGT_ERROR:
			spdk_app_stop(rc);
			return;
		}

	} while (g_tgt.state != prev_state);
}

int
spdk_nvmf_tgt_start(struct spdk_app_opts *opts)
{
	int rc;

	opts->shutdown_cb = spdk_nvmf_shutdown_cb;

	/* Blocks until the application is exiting */
	rc = spdk_app_start(opts, nvmf_tgt_advance_state, NULL, NULL);

	spdk_app_fini();

	return rc;
}