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

#include <zephyr/kernel.h>
#include <stdio.h>
#include <zephyr/drivers/uart.h>
#include <string.h>
#include <zephyr/random/rand32.h>
#include <zephyr/net/mqtt.h>
#include <zephyr/net/socket.h>
#include <zephyr/shell/shell.h>
#include <hw_id.h>
#if defined(CONFIG_NRF_MODEM_LIB)
#include <nrf_modem_at.h>
#endif /* CONFIG_NRF_MODEM_LIB */
#include <modem/lte_lc.h>
#include <zephyr/logging/log.h>
#if defined(CONFIG_MODEM_KEY_MGMT)
#include <modem/modem_key_mgmt.h>
#endif
#include <dk_buttons_and_leds.h>

#include "certificates.h"

#include <nrf9160.h>
#include <stdio.h>
#include <string.h>
#include <zephyr/drivers/adc.h>

struct device *adc_dev;
uint8_t sensors_enabled = 0xff; // bit 0 - PIR, bit 1 - HAL, bit 2 - temperature, bit 3 - gas 

#include <hal/nrf_saadc.h>
#define ADC_DEVICE_NAME DT_NODELABEL(adc)
#define ADC_RESOLUTION 10
#define ADC_GAIN ADC_GAIN_1_2
#define ADC_REFERENCE ADC_REF_INTERNAL
#define ADC_ACQUISITION_TIME ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 10)

static const struct adc_channel_cfg adc_temp_channel_cfg = {
	.gain = ADC_GAIN,
	.reference = ADC_REFERENCE,
	.acquisition_time = ADC_ACQUISITION_TIME,
	.channel_id = 4,
#if defined(CONFIG_ADC_CONFIGURABLE_INPUTS)
	.input_positive = 5,
#endif
};

static const struct adc_channel_cfg adc_gas_channel_cfg = {
	.gain = ADC_GAIN,
	.reference = ADC_REFERENCE,
	.acquisition_time = ADC_ACQUISITION_TIME,
	.channel_id = 5,
#if defined(CONFIG_ADC_CONFIGURABLE_INPUTS)
	.input_positive = 6,
#endif
};


static int16_t adc_sample(uint8_t idx)
{
	int ret;
	int16_t temp; //mV

	if(idx > 1) return -1;

	const struct adc_sequence sequence = {
		.channels = BIT(idx + 4), // choose AIN4 on AIN5
		.buffer = &temp,          // only single value, make to pointer to simulate array 
		.buffer_size = sizeof(temp),
		.resolution = ADC_RESOLUTION,
	};

	if (!adc_dev) {
		return -1;
	}

	ret = adc_read(adc_dev, &sequence);

	temp = (temp * 6) / 5; // simple aproximation of 0-1023 range to 0-1200 mV range

	return temp;
}

LOG_MODULE_REGISTER(mqtt_simple, CONFIG_MQTT_SIMPLE_LOG_LEVEL);

/* Buffers for MQTT client. */
static uint8_t rx_buffer[CONFIG_MQTT_MESSAGE_BUFFER_SIZE];
static uint8_t tx_buffer[CONFIG_MQTT_MESSAGE_BUFFER_SIZE];
static uint8_t payload_buf[CONFIG_MQTT_PAYLOAD_BUFFER_SIZE];

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

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

/* File descriptor */
static struct pollfd fds;

#if defined(CONFIG_MQTT_LIB_TLS)
static int certificates_provision(void)
{
	int err = 0;

	LOG_INF("Provisioning certificates");

#if defined(CONFIG_NRF_MODEM_LIB) && defined(CONFIG_MODEM_KEY_MGMT)

	err = modem_key_mgmt_write(CONFIG_MQTT_TLS_SEC_TAG,
				   MODEM_KEY_MGMT_CRED_TYPE_CA_CHAIN,
				   CA_CERTIFICATE,
				   strlen(CA_CERTIFICATE));
	if (err) {
		LOG_ERR("Failed to provision CA certificate: %d", err);
		return err;
	}

#elif defined(CONFIG_BOARD_QEMU_X86) && defined(CONFIG_NET_SOCKETS_SOCKOPT_TLS)

	err = tls_credential_add(CONFIG_MQTT_TLS_SEC_TAG,
				 TLS_CREDENTIAL_CA_CERTIFICATE,
				 CA_CERTIFICATE,
				 sizeof(CA_CERTIFICATE));
	if (err) {
		LOG_ERR("Failed to register CA certificate: %d", err);
		return err;
	}

#endif

	return err;
}
#endif /* defined(CONFIG_MQTT_LIB_TLS) */

/**@brief Function to print strings without null-termination
 */
static void data_print(uint8_t *prefix, uint8_t *data, size_t len)
{
	char buf[len + 1];

	memcpy(buf, data, len);
	buf[len] = 0;
	LOG_INF("%s%s", (char *)prefix, (char *)buf);
}

/**@brief Function to publish data on a topic
 */
static int data_publish(struct mqtt_client *c, enum mqtt_qos qos, const char *topic,
	uint8_t *data, size_t len)
{
	struct mqtt_publish_param param;

	param.message.topic.qos = qos;
	param.message.topic.topic.utf8 = topic;
	param.message.topic.topic.size = strlen(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);
	LOG_INF("to topic: %s len: %u",
		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
	};

	LOG_INF("Subscribing to: %s len %u", 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)
{
	int ret;
	int err = 0;

	/* Return an error if the payload is larger than the payload buffer.
	 * Note: To allow new messages, we have to read the payload before returning.
	 */
	if (length > sizeof(payload_buf)) {
		err = -EMSGSIZE;
	}

	/* Truncate payload until it fits in the payload buffer. */
	while (length > sizeof(payload_buf)) {
		ret = mqtt_read_publish_payload_blocking(
				c, payload_buf, (length - sizeof(payload_buf)));
		if (ret == 0) {
			return -EIO;
		} else if (ret < 0) {
			return ret;
		}

		length -= ret;
	}

	ret = mqtt_readall_publish_payload(c, payload_buf, length);
	if (ret) {
		return ret;
	}

	return err;
}

/**@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) {
			LOG_ERR("MQTT connect failed: %d", evt->result);
			break;
		}

		LOG_INF("MQTT client connected");
		subscribe();
		break;

	case MQTT_EVT_DISCONNECT:
		LOG_INF("MQTT client disconnected: %d", evt->result);
		break;

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

		LOG_INF("MQTT PUBLISH result=%d len=%d",
			evt->result, p->message.payload.len);
		err = publish_get_payload(c, p->message.payload.len);

		if (p->message.topic.qos == MQTT_QOS_1_AT_LEAST_ONCE) {
			const struct mqtt_puback_param ack = {
				.message_id = p->message_id
			};

			/* Send acknowledgment. */
			mqtt_publish_qos1_ack(&client, &ack);
		}

		if (err >= 0) {
			data_print("Received: ", payload_buf,
				p->message.payload.len);
			
			// for both way communication demonstration: ox turn on led x, [any other char]x turns off led x
			if(p->message.payload.len >= 2 && payload_buf[1] >= '0' && payload_buf[1] <= '3') {
				dk_set_led(payload_buf[1] - 48, payload_buf[0] == 'o');
			}

			/* Echo back received data */
			data_publish(&client, MQTT_QOS_1_AT_LEAST_ONCE, "nrf/echo",
				payload_buf, p->message.payload.len);
		} else if (err == -EMSGSIZE) {
			LOG_ERR("Received payload (%d bytes) is larger than the payload buffer "
				"size (%d bytes).",
				p->message.payload.len, sizeof(payload_buf));
		} else {
			LOG_ERR("publish_get_payload failed: %d", err);
			LOG_INF("Disconnecting MQTT client...");

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

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

		LOG_INF("PUBACK packet id: %u", evt->param.puback.message_id);
		break;

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

		LOG_INF("SUBACK packet id: %u", evt->param.suback.message_id);
		break;

	case MQTT_EVT_PINGRESP:
		if (evt->result != 0) {
			LOG_ERR("MQTT PINGRESP error: %d", evt->result);
		}
		break;

	default:
		LOG_INF("Unhandled MQTT event type: %d", evt->type);
		break;
	}
}

/**@brief Resolves the configured hostname and
 * initializes the MQTT broker structure
 */
static int 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) {
		LOG_ERR("getaddrinfo failed: %d", err);
		return -ECHILD;
	}

	addr = result;

	/* 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));
			LOG_INF("IPv4 Address found %s", ipv4_addr);

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

		addr = addr->ai_next;
	}

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

	return err;
}

#define RANDOM_LEN 10
#define CLIENT_ID_LEN sizeof(CONFIG_BOARD) + 1 + RANDOM_LEN

/* Function to get the client id */
static const uint8_t* client_id_get(void)
{
	static uint8_t client_id[MAX(sizeof(CONFIG_MQTT_CLIENT_ID),
				     CLIENT_ID_LEN)];

	if (strlen(CONFIG_MQTT_CLIENT_ID) > 0) {
		snprintf(client_id, sizeof(client_id), "%s",
			 CONFIG_MQTT_CLIENT_ID);
		goto exit;
	}

	char hw_id_buf[HW_ID_LEN] = {0};

	int err = hw_id_get(hw_id_buf, ARRAY_SIZE(hw_id_buf));

	if (!err) {
		snprintf(client_id, sizeof(client_id), "nrf-%s",
			 hw_id_buf);
		goto exit;
	}

	LOG_ERR("failed to retrieve HW ID, err: %d", err);

	uint32_t id = sys_rand32_get();
	snprintf(client_id, sizeof(client_id), "%s-%010u", CONFIG_BOARD, id);

exit:
	LOG_DBG("client_id = %s", (char *)client_id);

	return client_id;
}

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

	mqtt_client_init(client);

	err = broker_init();
	if (err) {
		LOG_ERR("Failed to initialize broker connection");
		return err;
	}

	/* MQTT client configuration */
	client->broker = &broker;
	client->evt_cb = mqtt_evt_handler;
	client->client_id.utf8 = client_id_get();
	client->client_id.size = strlen(client->client_id.utf8);
	client->password = NULL;
	client->user_name = NULL;
	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)
	struct mqtt_sec_config *tls_cfg = &(client->transport).tls.config;
	static sec_tag_t sec_tag_list[] = { CONFIG_MQTT_TLS_SEC_TAG };

	LOG_INF("TLS enabled");
	client->transport.type = MQTT_TRANSPORT_SECURE;

	tls_cfg->peer_verify = CONFIG_MQTT_TLS_PEER_VERIFY;
	tls_cfg->cipher_count = 0;
	tls_cfg->cipher_list = NULL;
	tls_cfg->sec_tag_count = ARRAY_SIZE(sec_tag_list);
	tls_cfg->sec_tag_list = sec_tag_list;
	tls_cfg->hostname = CONFIG_MQTT_BROKER_HOSTNAME;

#if defined(CONFIG_NRF_MODEM_LIB)
	tls_cfg->session_cache = IS_ENABLED(CONFIG_MQTT_TLS_SESSION_CACHING) ?
					    TLS_SESSION_CACHE_ENABLED :
					    TLS_SESSION_CACHE_DISABLED;
#else
	/* TLS session caching is not supported by the Zephyr network stack */
	tls_cfg->session_cache = TLS_SESSION_CACHE_DISABLED;

#endif

#else
	client->transport.type = MQTT_TRANSPORT_NON_SECURE;
#endif

	return err;
}

/**@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;
}

#if defined(CONFIG_DK_LIBRARY)
static void button_handler(uint32_t button_states, uint32_t has_changed)
{
	// After inicializtion pressed button and active switch make sensor disabled 
	if(sensors_enabled == 0xff) {
		sensors_enabled = (~button_states) & 0xf; // mask only 4 real buttons
	}

	if (has_changed & button_states &
	    BIT(CONFIG_BUTTON_EVENT_BTN_NUM - 1)) {
		int ret;

		ret = data_publish(&client,
				   MQTT_QOS_1_AT_LEAST_ONCE,
				   "nrf/button",
				   "1 pressed",
				   9);
		if (ret) {
			LOG_ERR("Publish failed: %d", ret);
		}
	}

	if ((has_changed & BIT(4)) && (sensors_enabled & BIT(0))) {
		int ret;

		dk_set_led(0, button_states & BIT(4));

		ret = data_publish(&client,
				   MQTT_QOS_1_AT_LEAST_ONCE,
				   "nrf/pir",
				   (button_states & BIT(4))? "1":"0",
				   1);
		if (ret) {
			LOG_ERR("Publish failed: %d", ret);
		}
	}

	if (has_changed & BIT(5) && (sensors_enabled & BIT(1))) {
		int ret;

		dk_set_led(1, button_states & BIT(5));

		ret = data_publish(&client,
				   MQTT_QOS_1_AT_LEAST_ONCE,
				   "nrf/magnet",
				   (has_changed & BIT(5))? "1":"0",
				   1);
		if (ret) {
			LOG_ERR("Publish failed: %d", ret);
		}
	}
}

#endif

static int shell_mqtt_publish(const struct shell *shell, size_t argc, char **argv)
{
	ARG_UNUSED(argc);
	ARG_UNUSED(argv);

	int ret;

	ret = data_publish(&client,
			   MQTT_QOS_1_AT_LEAST_ONCE,
			   CONFIG_MQTT_PUB_TOPIC,
			   CONFIG_BUTTON_EVENT_PUBLISH_MSG,
			   sizeof(CONFIG_BUTTON_EVENT_PUBLISH_MSG) - 1);
	if (ret) {
		LOG_ERR("Publish failed: %d", ret);
	}

	return ret;
}

SHELL_STATIC_SUBCMD_SET_CREATE(mqtt_sub,
		SHELL_CMD(publish, NULL, "Publish data to configured publish topic",
			shell_mqtt_publish),
		SHELL_SUBCMD_SET_END /* Array terminated. */
);
SHELL_CMD_REGISTER(mqtt, &mqtt_sub, "MQTT operations", NULL);

/**@brief Configures modem to provide LTE link. Blocks until link is
 * successfully established.
 */
static int modem_configure(void)
{
#if defined(CONFIG_LTE_LINK_CONTROL)
	/* Turn off LTE power saving features for a more responsive demo. Also,
	 * request power saving features before network registration. Some
	 * networks rejects timer updates after the device has registered to the
	 * LTE network.
	 */
	LOG_INF("Disabling PSM and eDRX");
	lte_lc_psm_req(false);
	lte_lc_edrx_req(false);

	if (IS_ENABLED(CONFIG_LTE_AUTO_INIT_AND_CONNECT)) {
		/* Do nothing, modem is already turned on
		 * and connected.
		 */
	} else {
		int err;

		LOG_INF("LTE Link Connecting...");
		err = lte_lc_init_and_connect();
		if (err) {
			LOG_INF("Failed to establish LTE connection: %d", err);
			return err;
		}
		LOG_INF("LTE Link Connected!");
	}
#endif /* defined(CONFIG_LTE_LINK_CONTROL) */

	return 0;
}

void main(void)
{
	int err;
	uint32_t connect_attempt = 0, last_measurement = 0;

	uint16_t adcval = 0;
	uint8_t buf[10];

	LOG_INF("The MQTT simple sample started");

#if defined(CONFIG_MQTT_LIB_TLS)
	err = certificates_provision();
	if (err != 0) {
		LOG_ERR("Failed to provision certificates");
		return;
	}
#endif /* defined(CONFIG_MQTT_LIB_TLS) */

	do {
		err = modem_configure();
		if (err) {
			LOG_INF("Retrying in %d seconds",
				CONFIG_LTE_CONNECT_RETRY_DELAY_S);
			k_sleep(K_SECONDS(CONFIG_LTE_CONNECT_RETRY_DELAY_S));
		}
	} while (err);

	err = client_init(&client);
	if (err != 0) {
		LOG_ERR("client_init: %d", err);
		return;
	}

#if defined(CONFIG_DK_LIBRARY)
	dk_buttons_init(button_handler);
	dk_leds_init();

	adc_dev =  DEVICE_DT_GET(ADC_DEVICE_NAME);

	if (!adc_dev) {
		printk("device_get_binding ADC failed\n");
		while(1);
	}
	err = adc_channel_setup(adc_dev, &adc_temp_channel_cfg);
	if (err) {
		printk("Error in adc setup: %d\n", err);
	}

	err = adc_channel_setup(adc_dev, &adc_gas_channel_cfg);
	if (err) {
		printk("Error in adc setup: %d\n", err);
	}
#endif

do_connect:
	if (connect_attempt++ > 0) {
		LOG_INF("Reconnecting in %d seconds...",
			CONFIG_MQTT_RECONNECT_DELAY_S);
		k_sleep(K_SECONDS(CONFIG_MQTT_RECONNECT_DELAY_S));
	}
	err = mqtt_connect(&client);
	if (err != 0) {
		LOG_ERR("mqtt_connect %d", err);
		goto do_connect;
	}

	err = fds_init(&client);
	if (err != 0) {
		LOG_ERR("fds_init: %d", err);
		return;
	}

	// One second blink with all led to inform abot
	dk_set_leds(0b1111);
	k_msleep(1000);
	dk_set_leds(0b1111);

	while (1) {
		err = poll(&fds, 1, mqtt_keepalive_time_left(&client));
		if (err < 0) {
			LOG_ERR("poll: %d", errno);
			break;
		}

		err = mqtt_live(&client);
		if ((err != 0) && (err != -EAGAIN)) {
			LOG_ERR("ERROR: mqtt_live: %d", err);
			break;
		}

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

		if ((fds.revents & POLLERR) == POLLERR) {
			LOG_ERR("POLLERR");
			break;
		}

		if ((fds.revents & POLLNVAL) == POLLNVAL) {
			LOG_ERR("POLLNVAL");
			break;
		}

		if(last_measurement < (NRF_RTC1->COUNTER) || last_measurement + 1000000 > (NRF_RTC1->COUNTER))
		{
			last_measurement = (NRF_RTC1->COUNTER);
			if (sensors_enabled & BIT(2)) { //enabled temperature
				// Sample AIN4 - LM35
				adcval = adc_sample(0);
				printk("Temp: %d mV\n", adcval);
				
				if(adcval > 280) { // 26 deg C
					snprintf(buf, 10, "%d", adcval);
					data_publish(&client, MQTT_QOS_1_AT_LEAST_ONCE, "nrf/temp", buf, strlen(buf));
					dk_set_led(2, 1);
					k_msleep(1000);
				}
				else dk_set_led(2, 0);
			}

			if (sensors_enabled & BIT(3)) { // enabled gas
				// Sample AIN5 - gas sensor
				adcval = adc_sample(1);
				printk("Gas: %d mV  %d\n", adcval, sensors_enabled);

				if(adcval > 200) { // reliable limit got by testing
					snprintf(buf, 10, "%d", adcval);
					data_publish(&client, MQTT_QOS_1_AT_LEAST_ONCE, "nrf/gas", buf, strlen(buf));
					dk_set_led(3, 1);
					k_msleep(1000);
				}
				else dk_set_led(3, 0);
			}
		}

	}

	LOG_INF("Disconnecting MQTT client...");

	err = mqtt_disconnect(&client);
	if (err) {
		LOG_ERR("Could not disconnect MQTT client: %d", err);
	}
	goto do_connect;
}