/*
 * Copyright (c) 2018 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-BSD-5-Clause-Nordic
 */

#include <zephyr.h>
#include <stdio.h>
#include <uart.h>
#include <string.h>

#include <net/mqtt.h>
#include <net/socket.h>
#include <lte_lc.h>

#include "certificates.h"

#if defined(CONFIG_PROVISION_CERTIFICATES)
#if defined(CONFIG_BSD_LIBRARY)
#include "nrf_inbuilt_key.h"
#endif
#endif

#if defined CONFIG_MQTT_LIB_TLS
static sec_tag_t sec_tag_list[] = { CONFIG_SEC_TAG };
#endif

#define AZ_Pass                                                                \
	"azureiothubpass"
#define AZ_User_Name                                                           \
	"azureiothubusername"
#define Test_Pass "XXXXXXXXX"
#define Test_User_Name "XXXXXXXXXX"

/* Buffers for MQTT client. */
static u8_t rx_buffer[CONFIG_MQTT_MESSAGE_BUFFER_SIZE];
static u8_t tx_buffer[CONFIG_MQTT_MESSAGE_BUFFER_SIZE];
static u8_t payload_buf[CONFIG_MQTT_PAYLOAD_BUFFER_SIZE];

/* The mqtt client struct */
static struct mqtt_client client;

/*Client username/pass*/
struct mqtt_utf8 pass, user_name;

/* MQTT Broker details. */
static struct sockaddr_storage broker;

/* Connected flag */
static bool connected;

/* File descriptor */
static struct pollfd fds;

#if defined(CONFIG_BSD_LIBRARY)

/**@brief Recoverable BSD library error. */
void bsd_recoverable_error_handler(uint32_t err)
{
	printk("bsdlib recoverable error: %u\n", err);
}

/**@brief Irrecoverable BSD library error. */
void bsd_irrecoverable_error_handler(uint32_t err)
{
	printk("bsdlib irrecoverable error: %u\n", err);

	__ASSERT_NO_MSG(false);
}

#endif /* defined(CONFIG_BSD_LIBRARY) */

/**@brief Function to print strings without null-termination
 */
static void data_print(u8_t *prefix, u8_t *data, size_t len)
{
	char buf[len + 1];

	memcpy(buf, data, len);
	buf[len] = 0;
	printk("%s%s\n", prefix, buf);
}

/**@brief Function to publish data on the configured topic
 */
static int data_publish(struct mqtt_client *c, enum mqtt_qos qos, u8_t *data,
			size_t len)
{
	struct mqtt_publish_param param;

	param.message.topic.qos = qos;
	param.message.topic.topic.utf8 = CONFIG_MQTT_PUB_TOPIC;
	param.message.topic.topic.size = strlen(CONFIG_MQTT_PUB_TOPIC);
	param.message.payload.data = data;
	param.message.payload.len = len;
	param.message_id = sys_rand32_get();
	param.dup_flag = 0;
	param.retain_flag = 0;

	data_print("Publishing: ", data, len);
	printk("to topic: %s len: %u\n", CONFIG_MQTT_PUB_TOPIC,
	       (unsigned int)strlen(CONFIG_MQTT_PUB_TOPIC));

	return mqtt_publish(c, &param);
}

/**@brief Function to subscribe to the configured topic
 */
static int subscribe(void)
{
	struct mqtt_topic subscribe_topic = {
		.topic = { .utf8 = CONFIG_MQTT_SUB_TOPIC,
			   .size = strlen(CONFIG_MQTT_SUB_TOPIC) },
		.qos = MQTT_QOS_1_AT_LEAST_ONCE
	};

	const struct mqtt_subscription_list subscription_list = {
		.list = &subscribe_topic, .list_count = 1, .message_id = 1234
	};

	printk("Subscribing to: %s len %u\n", CONFIG_MQTT_SUB_TOPIC,
	       (unsigned int)strlen(CONFIG_MQTT_SUB_TOPIC));

	return mqtt_subscribe(&client, &subscription_list);
}

/**@brief Function to read the published payload.
 */
static int publish_get_payload(struct mqtt_client *c, size_t length)
{
	u8_t *buf = payload_buf;
	u8_t *end = buf + length;

	if (length > sizeof(payload_buf)) {
		return -EMSGSIZE;
	}

	while (buf < end) {
		int ret = mqtt_read_publish_payload(c, buf, end - buf);

		if (ret < 0) {
			int err;

			if (ret != -EAGAIN) {
				return ret;
			}

			printk("mqtt_read_publish_payload: EAGAIN\n");

			err = poll(&fds, 1, K_SECONDS(CONFIG_MQTT_KEEPALIVE));
			if (err > 0 && (fds.revents & POLLIN) == POLLIN) {
				continue;
			} else {
				return -EIO;
			}
		}

		if (ret == 0) {
			return -EIO;
		}

		buf += ret;
	}

	return 0;
}

/**@brief MQTT client event handler
 */
void mqtt_evt_handler(struct mqtt_client *const c, const struct mqtt_evt *evt)
{
	int err;

	switch (evt->type) {
	case MQTT_EVT_CONNACK:
		if (evt->result != 0) {
			printk("MQTT connect failed %d\n",
			       evt->result); //this is executed...why?
			break;
		}

		connected = true;
		printk("[%s:%d] MQTT client connected!\n", __func__, __LINE__);
		subscribe();
		break;

	case MQTT_EVT_DISCONNECT:
		printk("[%s:%d] MQTT client disconnected %d\n", __func__,
		       __LINE__, evt->result);

		connected = false;
		break;

	case MQTT_EVT_PUBLISH: {
		const struct mqtt_publish_param *p = &evt->param.publish;

		printk("[%s:%d] MQTT PUBLISH result=%d len=%d\n", __func__,
		       __LINE__, evt->result, p->message.payload.len);
		err = publish_get_payload(c, p->message.payload.len);
		if (err >= 0) {
			data_print("Received: ", payload_buf,
				   p->message.payload.len);
			/* Echo back received data */
			data_publish(&client, MQTT_QOS_1_AT_LEAST_ONCE,
				     payload_buf, p->message.payload.len);
		} else {
			printk("mqtt_read_publish_payload: Failed! %d\n", err);
			printk("Disconnecting MQTT client...\n");

			err = mqtt_disconnect(c);
			if (err) {
				printk("Could not disconnect: %d\n", err);
			}
		}
	} break;

	case MQTT_EVT_PUBACK:
		if (evt->result != 0) {
			printk("MQTT PUBACK error %d\n", evt->result);
			break;
		}

		printk("[%s:%d] PUBACK packet id: %u\n", __func__, __LINE__,
		       evt->param.puback.message_id);
		break;

	case MQTT_EVT_SUBACK:
		if (evt->result != 0) {
			printk("MQTT SUBACK error %d\n", evt->result);
			break;
		}

		printk("[%s:%d] SUBACK packet id: %u\n", __func__, __LINE__,
		       evt->param.suback.message_id);
		break;

	default:
		printk("[%s:%d] default: %d\n", __func__, __LINE__, evt->type);
		break;
	}
}

/**@brief Resolves the configured hostname and
 * initializes the MQTT broker structure
 */
static void broker_init(void)
{
	int err;
	struct addrinfo *result;
	struct addrinfo *addr;
	struct addrinfo hints = { .ai_family = AF_INET,
				  .ai_socktype = SOCK_STREAM };

	err = getaddrinfo(CONFIG_MQTT_BROKER_HOSTNAME, NULL, &hints, &result);
	if (err) {
		printk("ERROR: getaddrinfo failed %d\n", err);

		return;
	}

	addr = result;
	err = -ENOENT;

	/* Look for address of the broker. */
	while (addr != NULL) {
		/* IPv4 Address. */
		if (addr->ai_addrlen == sizeof(struct sockaddr_in)) {
			struct sockaddr_in *broker4 =
				((struct sockaddr_in *)&broker);
			char ipv4_addr[NET_IPV4_ADDR_LEN];

			broker4->sin_addr.s_addr =
				((struct sockaddr_in *)addr->ai_addr)
					->sin_addr.s_addr;
			broker4->sin_family = AF_INET;
			broker4->sin_port = htons(CONFIG_MQTT_BROKER_PORT);

			inet_ntop(AF_INET, &broker4->sin_addr.s_addr, ipv4_addr,
				  sizeof(ipv4_addr));
			printk("IPv4 Address found %s\n", ipv4_addr);

			break;
		} else {
			printk("ai_addrlen = %u should be %u or %u\n",
			       (unsigned int)addr->ai_addrlen,
			       (unsigned int)sizeof(struct sockaddr_in),
			       (unsigned int)sizeof(struct sockaddr_in6));
		}

		addr = addr->ai_next;
		break;
	}

	/* Free the address. */
	freeaddrinfo(result);
}

/**@brief Initialize the MQTT client structure
 */
static void client_init(struct mqtt_client *client)
{
	mqtt_client_init(client);

	pass.size = strlen(AZ_Pass);
	pass.utf8 = (u8_t *)AZ_Pass;
	user_name.size = strlen(AZ_User_Name);
	user_name.utf8 = (u8_t *)AZ_User_Name;

	broker_init();

	/* MQTT client configuration */
	client->broker = &broker;
	client->evt_cb = mqtt_evt_handler;
	client->client_id.utf8 = (u8_t *)CONFIG_MQTT_CLIENT_ID;
	client->client_id.size = strlen(CONFIG_MQTT_CLIENT_ID);
	client->password = &pass;
	client->user_name = &user_name;
	client->protocol_version = MQTT_VERSION_3_1_1;

	/* MQTT buffers configuration */
	client->rx_buf = rx_buffer;
	client->rx_buf_size = sizeof(rx_buffer);
	client->tx_buf = tx_buffer;
	client->tx_buf_size = sizeof(tx_buffer);

	/* MQTT transport configuration */
#if defined(CONFIG_MQTT_LIB_TLS)
	client->transport.type = MQTT_TRANSPORT_SECURE;
	client->transport.tls.config.peer_verify = 2; //formerly 0
	client->transport.tls.config.cipher_count = 0;
	client->transport.tls.config.cipher_list = NULL;
	client->transport.tls.config.sec_tag_count = ARRAY_SIZE(sec_tag_list); // formerly 0
	client->transport.tls.config.sec_tag_list = sec_tag_list; //formerly NULL
	client->transport.tls.config.hostname = CONFIG_MQTT_BROKER_HOSTNAME;
#else
	client->transport.type = MQTT_TRANSPORT_NON_SECURE;
#endif
}

/**@brief Initialize the file descriptor structure used by poll.
 */
static int fds_init(struct mqtt_client *c)
{
	if (c->transport.type == MQTT_TRANSPORT_NON_SECURE) {
		fds.fd = c->transport.tcp.sock;
	} 
	else {
#if defined(CONFIG_MQTT_LIB_TLS)
		fds.fd = c->transport.tls.sock;
#else
		return -ENOTSUP;
#endif
	}

	fds.events = POLLIN;
	return 0;
}

/**@brief Configures modem to provide LTE link. Blocks until link is
 * successfully established.
 */
static void modem_configure(void)
{
#if defined(CONFIG_LTE_LINK_CONTROL)
	if (IS_ENABLED(CONFIG_LTE_AUTO_INIT_AND_CONNECT)) {
		/* Do nothing, modem is already turned on
		 * and connected.
		 */
	} 
	else {
		int err;

		printk("LTE Link Connecting ...\n");
		err = lte_lc_init_and_connect();
		__ASSERT(err == 0, "LTE link could not be established.");
		printk("LTE Link Connected!\n");
	}
#endif
}


static int provision_certificates(void)
{
    {
#if defined(CONFIG_PROVISION_CERTIFICATES)
#if defined(CONFIG_BSD_LIBRARY)
	
		int err;

		/* Delete Certificates */
		nrf_sec_tag_t sec_tag = (nrf_sec_tag_t)sec_tag_list[0];

		for (nrf_key_mgnt_cred_type_t type = 0; type < 5; type++) {
			printk("Deleting certs sec_tag: %d\n", sec_tag);
			err = nrf_inbuilt_key_delete(sec_tag, type);
			printk("nrf_inbuilt_key_delete(%u, %d) => result%d\n",
			       sec_tag, type, err);
		}

#if defined(AZ_ROOT_CERTIFICATE)
		/*provision CA certificates*/
		printk("Write ca certs sec_tag: %d\n", sec_tag);
		err = nrf_inbuilt_key_write(sec_tag,
					    NRF_KEY_MGMT_CRED_TYPE_CA_CHAIN,
					    AZ_ROOT_CERTIFICATE,
					    strlen(AZ_ROOT_CERTIFICATE));
		if (err) {
			printk("AZ_ROOT_CERTIFICATE err: %d", err);
			return err;
		}
#endif //end az_root_certificate

#if defined(CLIENT_PRIVATE_KEY)
		/* provision private certificate */
		printk("Write private cert sec_tag: %d\n", sec_tag);
		err = nrf_inbuilt_key_write(sec_tag,
					    NRF_KEY_MGMT_CRED_TYPE_PRIVATE_CERT,
					    CLIENT_PRIVATE_KEY,
					    strlen(CLIENT_PRIVATE_KEY));
		if (err) {
			printk("CLIENT_PRIVATE_KEY err: %d\n", err);
			return err;
		}
#endif //client_private_key

#if defined(CLIENT_PUBLIC_CERTIFICATE)
		/* provision public certificate */
		printk("Write public cert sec_tag: %d\n", sec_tag);
		err = nrf_inbuilt_key_write(sec_tag,
					    NRF_KEY_MGMT_CRED_TYPE_PUBLIC_CERT,
					    CLIENT_PUBLIC_CERTIFICATE,
					    strlen(CLIENT_PUBLIC_CERTIFICATE));
		if (err) {
			printk("CLIENT_PUBLIC_CERTIFICATE err: %d\n", err);
			return err;
		}
	}
#endif //client_public_certificate
#else
	{
		int err;

		err = tls_credential_add(CONFIG_SEC_TAG,
					 TLS_CREDENTIAL_CA_CERTIFICATE,
					 NRF_CLOUD_CA_CERTIFICATE,
					 sizeof(NRF_CLOUD_CA_CERTIFICATE));
		if (err < 0) {
			printk("Failed to register ca certificate: %d\n", err);
			return err;
		}

		err = tls_credential_add(CONFIG_SEC_TAG,
					 TLS_CREDENTIAL_PRIVATE_KEY,
					 NRF_CLOUD_CLIENT_PRIVATE_KEY,
					 sizeof(NRF_CLOUD_CLIENT_PRIVATE_KEY));
		if (err < 0) {
			printk("Failed to register private key: %d\n", err);
			return err;
		}

		err = tls_credential_add(
			CONFIG_SEC_TAG, TLS_CREDENTIAL_SERVER_CERTIFICATE,
			NRF_CLOUD_CLIENT_PUBLIC_CERTIFICATE,
			sizeof(NRF_CLOUD_CLIENT_PUBLIC_CERTIFICATE));
		if (err < 0) {
			printk("Failed to register public certificate: %d\n",
			       err);
			return err;
		}

#endif //defined(config_bsd_library)
#endif //defined(config_provision_certificates)
	}
return 0;
}

void main(void)
{
	int err;

	printk("The MQTT simple sample started\n");

	provision_certificates();

	modem_configure();

	client_init(&client);

	err = mqtt_connect(&client);
	if (err != 0) {
		printk("ERROR: mqtt_connect %d\n", err);
		return;
	}

	err = fds_init(&client);
	if (err != 0) {
		printk("ERROR: fds_init %d\n", err);
		return;
	}

	printk("NOW ENTERING ENDLESS POLLING LOOP\n");
	while (1) {
		err = poll(&fds, 1, K_SECONDS(CONFIG_MQTT_KEEPALIVE));
		if (err < 0) {
			printk("ERROR: poll %d\n", errno);
			break;
		}

		err = mqtt_live(&client);
		if (err != 0) {
			printk("ERROR: mqtt_live %d\n", err);
			break;
		}

		if ((fds.revents & POLLIN) == POLLIN) {
			err = mqtt_input(&client);
			if (err != 0) {
				printk("ERROR: mqtt_input %d\n", err);
				break;
			}
		}

		if ((fds.revents & POLLERR) == POLLERR) {
			printk("POLLERR\n");
			break;
		}

		if ((fds.revents & POLLNVAL) == POLLNVAL) {
			printk("POLLNVAL\n");
			break;
		}
	}

	printk("Disconnecting MQTT client...\n");

	err = mqtt_disconnect(&client);
	if (err) {
		printk("Could not disconnect MQTT client. Error: %d\n",
		       err);
	}
}