/*
 * This Source Code Form is subject to the terms of the Mozilla Public License,
 * v. 2.0. If a copy of the MPL was not distributed with this file, You can
 * obtain one at https://mozilla.org/MPL/2.0/.
 */

#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>

#include <string.h>
#include <zephyr/init.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
#include <zephyr/logging/log_backend.h>
#include <zephyr/logging/log_backend_net.h>
#include <zephyr/logging/log_ctrl.h>
#include <zephyr/logging/log_core.h>
#include <zephyr/net/conn_mgr_connectivity.h>
#include <zephyr/settings/settings.h>
#include <zephyr/sys/util.h>

#ifdef CONFIG_IOT_CONTACT_NETWORK_HACK
#include <zephyr/sys/reboot.h>
#endif  // CONFIG_IOT_CONTACT_NETWORK_HACK

#include "settings.h"

LOG_MODULE_REGISTER(syslog);

#define NETWORK_BUG_DELAY K_MSEC(4000)
#define L4_EVENT_MASK (NET_EVENT_L4_CONNECTED | NET_EVENT_L4_DISCONNECTED)
#define SYSLOG_TARGET_PORT 514

struct net_mgmt_event_callback l4_cb;
static K_SEM_DEFINE(network_connected, 0, 1);
static char target_ip[IPV6_STRLEN_MAX + 1] = "2001:db8::2";

void l4_event_handler(
	struct net_mgmt_event_callback *cb,
	uint32_t event,
	struct net_if *iface)
{
	LOG_DBG("Executing L4 event handler");

	switch (event) {
	case NET_EVENT_L4_CONNECTED:
		k_sem_give(&network_connected);
		LOG_INF("Network connected");
		break;
	case NET_EVENT_L4_DISCONNECTED:
		LOG_INF("Network disconnected");
		break;
	default:
		break;
	}
}

int init_network_monitoring(void)
{
	net_mgmt_init_event_callback(&l4_cb, l4_event_handler, L4_EVENT_MASK);
	net_mgmt_add_event_callback(&l4_cb);

	return 0;
}
SYS_INIT(init_network_monitoring, APPLICATION, 0);

int init_syslog(void)
{
	LOG_DBG("Initializing syslog logging backend");

	LOG_INF("Waiting for network ...");

#ifdef CONFIG_IOT_CONTACT_NETWORK_HACK
	int ret = k_sem_take(&network_connected, NETWORK_BUG_DELAY);
	if (ret == -EAGAIN) {
		LOG_ERR("Could not connect to network - rebooting system");
		log_flush();
		sys_reboot(SYS_REBOOT_COLD);
	}
#else
	k_sem_take(&network_connected, K_FOREVER);
#endif  // CONFIG_IOT_CONTACT_NETWORK_HACK

	LOG_INF("Enabling syslog backend");
	const struct log_backend *backend = log_backend_net_get();
	if (log_backend_is_active(backend) == false) {
		/* flush log messages to ensure first syslog message is reproducible */
		while (log_process());
		log_backend_init(backend);
		log_backend_enable(backend, backend->cb->ctx, CONFIG_LOG_MAX_LEVEL);
		LOG_INF("Syslog backend enabled");
	} else {
		LOG_INF("Syslog backend was already enabled");
	}

	return 0;
}
SYS_INIT(init_syslog, APPLICATION, 40);

int syslog_handle_set(const char *name, size_t len, settings_read_cb read_cb,
                      void *cb_arg)
{
	const char* next = NULL;

	if (settings_name_steq(name, "target/ip", &next) && !next) {
		memset(target_ip, '\0', sizeof(target_ip));
		ssize_t ret = read_cb(cb_arg, target_ip, MIN(sizeof(target_ip) - 1, len));
		if (ret < 0) {
			LOG_ERR("Failed to set target IP (%d)", ret);
			return (int)ret;
		}
		LOG_INF("Set target IP to '%s'", target_ip);
		return 0;
	}

	return 0;
}

int syslog_handle_commit(void)
{
	char target[IPV6_STRLEN_MAX + 9];  // 9 for brackets, colon, port and \0

	int ret = snprintf(target, sizeof(target), "[%s]:%d", target_ip,
	                   SYSLOG_TARGET_PORT);
	if (ret < 0) {
		LOG_ERR("Failed to format target based on ip and port (%d)", ret);
		return ret;
	}

	if (log_backend_net_set_addr(target) == false) {
		LOG_ERR("Could not commit settings");
		return -EINVAL;
	}
	LOG_INF("Committed settings");

	return 0;
}

int syslog_handle_export(int (*cb)(const char *name, const void *value,
                         size_t val_len))
{
	LOG_WRN("Settings export not implemented");
	return 0;
}

int syslog_handle_get(const char *name, char *val, int val_len_max)
{
	const char* next = NULL;

	if (settings_name_steq(name, "target/ip", &next) && !next) {
		size_t len = strnlen(target_ip, sizeof(target_ip));
		memcpy(val, target_ip, MIN(len, val_len_max));
	}

	return 0;
}

SETTINGS_STATIC_HANDLER_DEFINE(
	syslog_settings_handler,
	"syslog",
	syslog_handle_get,
	syslog_handle_set,
	syslog_handle_commit,
	syslog_handle_export
);