/*
 * Copyright (C) 2020  NetDEF, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program 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 General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zebra.h>
#include "pceplib/pcep_utils_counters.h"

#include "memory.h"
#include "log.h"
#include "command.h"
#include "libfrr.h"
#include "printfrr.h"
#include "lib/version.h"
#include "northbound.h"
#include "frr_pthread.h"
#include "jhash.h"
#include "termtable.h"

#include "pathd/pathd.h"
#include "pathd/path_errors.h"
#include "pathd/path_pcep.h"
#include "pathd/path_pcep_cli.h"
#include "pathd/path_pcep_controller.h"
#include "pathd/path_pcep_lib.h"
#include "pathd/path_pcep_config.h"
#include "pathd/path_pcep_debug.h"

DEFINE_MTYPE(PATHD, PCEP, "PCEP module");

/*
 * Globals.
 */
static struct pcep_glob pcep_glob_space = {.dbg = {0, "pathd module: pcep"}};
struct pcep_glob *pcep_g = &pcep_glob_space;

/* Main Thread Even Handler */
static int pcep_main_event_handler(enum pcep_main_event_type type, int pcc_id,
				   void *payload);
static int pcep_main_event_start_sync(int pcc_id);
static int pcep_main_event_start_sync_cb(struct path *path, void *arg);
static int pcep_main_event_initiate_candidate(struct path *path);
static int pcep_main_event_update_candidate(struct path *path);
static int pcep_main_event_remove_candidate_segments(const char *originator,
						     bool force);

/* Hook Handlers called from the Main Thread */
static int pathd_candidate_created_handler(struct srte_candidate *candidate);
static int pathd_candidate_updated_handler(struct srte_candidate *candidate);
static int pathd_candidate_removed_handler(struct srte_candidate *candidate);

/* Path manipulation functions */
static struct path_metric *pcep_copy_metrics(struct path_metric *metric);
static struct path_hop *pcep_copy_hops(struct path_hop *hop);

/* Other static functions */
static void notify_status(struct path *path, bool not_changed);

/* Module Functions */
static int pcep_module_finish(void);
static int pcep_module_late_init(struct thread_master *tm);
static int pcep_module_init(void);

/* ------------ Path Helper Functions ------------ */

struct path *pcep_new_path(void)
{
	struct path *path;
	path = XCALLOC(MTYPE_PCEP, sizeof(*path));
	path->binding_sid = MPLS_LABEL_NONE;
	path->enforce_bandwidth = true;
	return path;
}

struct path_hop *pcep_new_hop(void)
{
	struct path_hop *hop;
	hop = XCALLOC(MTYPE_PCEP, sizeof(*hop));
	return hop;
}

struct path_metric *pcep_new_metric(void)
{
	struct path_metric *metric;
	metric = XCALLOC(MTYPE_PCEP, sizeof(*metric));
	return metric;
}

struct path_metric *pcep_copy_metrics(struct path_metric *metric)
{
	if (metric == NULL)
		return NULL;
	struct path_metric *new_metric = pcep_new_metric();
	*new_metric = *metric;
	new_metric->next = pcep_copy_metrics(metric->next);
	return new_metric;
}

struct path_hop *pcep_copy_hops(struct path_hop *hop)
{
	if (hop == NULL)
		return NULL;
	struct path_hop *new_hop = pcep_new_hop();
	*new_hop = *hop;
	new_hop->next = pcep_copy_hops(hop->next);
	return new_hop;
}

struct path *pcep_copy_path(struct path *path)
{
	struct path *new_path = pcep_new_path();

	*new_path = *path;
	new_path->first_metric = pcep_copy_metrics(path->first_metric);
	new_path->first_hop = pcep_copy_hops(path->first_hop);
	if (path->name != NULL)
		new_path->name = XSTRDUP(MTYPE_PCEP, path->name);
	if (path->originator != NULL)
		new_path->originator = XSTRDUP(MTYPE_PCEP, path->originator);
	return new_path;
}

void pcep_free_path(struct path *path)
{
	struct path_hop *hop;
	struct path_metric *metric;
	char *tmp;

	metric = path->first_metric;
	while (metric != NULL) {
		struct path_metric *next = metric->next;
		XFREE(MTYPE_PCEP, metric);
		metric = next;
	}
	hop = path->first_hop;
	while (hop != NULL) {
		struct path_hop *next = hop->next;
		XFREE(MTYPE_PCEP, hop);
		hop = next;
	}
	if (path->originator != NULL) {
		/* The path own the memory, it is const so it is clear it
		shouldn't be modified. XFREE macro do not support type casting
		so we need a temporary variable */
		tmp = (char *)path->originator;
		XFREE(MTYPE_PCEP, tmp);
		path->originator = NULL;
	}
	if (path->name != NULL) {
		/* The path own the memory, it is const so it is clear it
		shouldn't be modified. XFREE macro do not support type casting
		so we need a temporary variable */
		tmp = (char *)path->name;
		XFREE(MTYPE_PCEP, tmp);
		path->name = NULL;
	}
	XFREE(MTYPE_PCEP, path);
}

/* ------------ Other Static Functions ------------ */

void notify_status(struct path *path, bool not_changed)
{
	struct path *resp = NULL;

	if ((resp = path_pcep_config_get_path(&path->nbkey))) {
		resp->srp_id = path->srp_id;
		flog_warn(EC_PATH_PCEP_RECOVERABLE_INTERNAL_ERROR,
			  "(%s) Send report for candidate path %s", __func__,
			  path->name);
		pcep_ctrl_send_report(pcep_g->fpt, path->pcc_id, resp,
				      not_changed);
	}
}

/* ------------ Main Thread Even Handler ------------ */

int pcep_main_event_handler(enum pcep_main_event_type type, int pcc_id,
			    void *payload)
{
	int ret = 0;

	switch (type) {
	case PCEP_MAIN_EVENT_START_SYNC:
		ret = pcep_main_event_start_sync(pcc_id);
		break;
	case PCEP_MAIN_EVENT_INITIATE_CANDIDATE:
		assert(payload != NULL);
		ret = pcep_main_event_initiate_candidate(
			(struct path *)payload);
		break;
	case PCEP_MAIN_EVENT_UPDATE_CANDIDATE:
		assert(payload != NULL);
		ret = pcep_main_event_update_candidate((struct path *)payload);
		break;
	case PCEP_MAIN_EVENT_REMOVE_CANDIDATE_LSP:
		ret = pcep_main_event_remove_candidate_segments(
			(const char *)payload, true);
		break;
	default:
		flog_warn(EC_PATH_PCEP_RECOVERABLE_INTERNAL_ERROR,
			  "Unexpected event received in the main thread: %u",
			  type);
		break;
	}

	return ret;
}

int pcep_main_event_start_sync(int pcc_id)
{
	path_pcep_config_list_path(pcep_main_event_start_sync_cb, &pcc_id);
	pcep_ctrl_sync_done(pcep_g->fpt, pcc_id);
	return 0;
}

int pcep_main_event_start_sync_cb(struct path *path, void *arg)
{
	int *pcc_id = (int *)arg;
	pcep_ctrl_sync_path(pcep_g->fpt, *pcc_id, path);
	return 1;
}

int pcep_main_event_initiate_candidate(struct path *path)
{
	int ret = 0;

	ret = path_pcep_config_initiate_path(path);
	if (path->do_remove) {
		struct pcep_error *error;
		error = XCALLOC(MTYPE_PCEP, sizeof(*error));
		error->path = path;
		error->error_type = PCEP_ERRT_INVALID_OPERATION;
		switch (ret) {
		case ERROR_19_1:
			error->error_value =
				PCEP_ERRV_LSP_UPDATE_FOR_NON_DELEGATED_LSP;
			break;
		case ERROR_19_3:
			error->error_value =
				PCEP_ERRV_LSP_UPDATE_UNKNOWN_PLSP_ID;
			break;
		case ERROR_19_9:
			error->error_value = PCEP_ERRV_LSP_NOT_PCE_INITIATED;
			break;
		default:
			zlog_warn("(%s)PCE tried to REMOVE unknown error!",
				  __func__);
			XFREE(MTYPE_PCEP, error);
			pcep_free_path(path);
			return ret;
			break;
		}
		pcep_ctrl_send_error(pcep_g->fpt, path->pcc_id, error);
	} else if (ret != PATH_NB_ERR && path->srp_id != 0)
		notify_status(path, ret == PATH_NB_NO_CHANGE);
	return ret;
}

int pcep_main_event_update_candidate(struct path *path)
{
	int ret = 0;

	ret = path_pcep_config_update_path(path);
	if (ret != PATH_NB_ERR && path->srp_id != 0)
		notify_status(path, ret == PATH_NB_NO_CHANGE);
	return ret;
}

int pcep_main_event_remove_candidate_segments(const char *originator,
					      bool force)
{
	srte_candidate_unset_segment_list(originator, force);
	/* Avoid compiler warnings about const char* */
	void *free_ptr = (void *)originator;
	XFREE(MTYPE_PCEP, free_ptr);

	srte_apply_changes();

	return 0;
}

/* ------------ Hook Handlers Functions Called From Main Thread ------------ */

int pathd_candidate_created_handler(struct srte_candidate *candidate)
{
	struct path *path = candidate_to_path(candidate);
	int ret = pcep_ctrl_pathd_event(pcep_g->fpt, PCEP_PATH_CREATED, path);
	return ret;
}

int pathd_candidate_updated_handler(struct srte_candidate *candidate)
{
	struct path *path = candidate_to_path(candidate);
	int ret = pcep_ctrl_pathd_event(pcep_g->fpt, PCEP_PATH_UPDATED, path);
	return ret;
}

int pathd_candidate_removed_handler(struct srte_candidate *candidate)
{
	struct path *path = candidate_to_path(candidate);
	int ret = pcep_ctrl_pathd_event(pcep_g->fpt, PCEP_PATH_REMOVED, path);
	return ret;
}


/* ------------ Module Functions ------------ */

/* this creates threads, therefore must run after fork().  but it must also
 * run before config load, so the CLI commands don't try to touch things that
 * aren't set up yet...
 */
static int pcep_module_config_pre(struct thread_master *tm)
{
	assert(pcep_g->fpt == NULL);
	assert(pcep_g->master == NULL);

	struct frr_pthread *fpt;

	if (pcep_ctrl_initialize(tm, &fpt, pcep_main_event_handler))
		return 1;

	if (pcep_lib_initialize(fpt))
		return 1;

	pcep_g->master = tm;
	pcep_g->fpt = fpt;

	return 0;
}

static int pcep_module_late_init(struct thread_master *tm)
{
	hook_register(pathd_candidate_created, pathd_candidate_created_handler);
	hook_register(pathd_candidate_updated, pathd_candidate_updated_handler);
	hook_register(pathd_candidate_removed, pathd_candidate_removed_handler);

	hook_register(frr_config_pre, pcep_module_config_pre);
	hook_register(frr_fini, pcep_module_finish);

	pcep_cli_init();

	return 0;
}

int pcep_module_finish(void)
{
	pcep_ctrl_finalize(&pcep_g->fpt);
	pcep_lib_finalize();

	for (int i = 0; i < MAX_PCC; i++)
		if (pcep_g->pce_opts_cli[i] != NULL)
			XFREE(MTYPE_PCEP, pcep_g->pce_opts_cli[i]);

	return 0;
}

int pcep_module_init(void)
{
	pcep_g->num_pce_opts_cli = 0;
	for (int i = 0; i < MAX_PCE; i++)
		pcep_g->pce_opts_cli[i] = NULL;
	pcep_g->num_config_group_opts = 0;
	for (int i = 0; i < MAX_PCE; i++)
		pcep_g->config_group_opts[i] = NULL;

	hook_register(frr_late_init, pcep_module_late_init);
	return 0;
}

FRR_MODULE_SETUP(.name = "frr_pathd_pcep", .version = FRR_VERSION,
		 .description = "FRR pathd PCEP module",
		 .init = pcep_module_init,
);