#include "mqtt.h"
#include "logger.h"

#include <mosquitto.h>

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


static void mosq_log_callback(struct mosquitto *mosq, void *userdata, int level, const char *str)
{
  switch (level) {
    case MOSQ_LOG_WARNING: log_warning("%s", str); break;
    case MOSQ_LOG_ERR:     log_error("%s", str); break;
  }
}

struct mosquitto *mqtt_open(const char *host, int port, int keepalive)
{
  struct mosquitto *mosq;
  int res;

  mosquitto_lib_init();

  /* Create MQTT client. */
  mosq = mosquitto_new(NULL, 1, NULL);
  if (mosq == NULL) {
    log_error("Cannot create mosquitto client: %s", strerror(errno));
    return NULL;
  }

  mosquitto_log_callback_set(mosq, mosq_log_callback);

  /* Connect to broker. */
  res = mosquitto_connect(mosq, host, port, keepalive);
  if (res != MOSQ_ERR_SUCCESS) {
    log_error("Unable to connect to MQTT broker %s:%d: %s", host, port, mosquitto_strerror(res));
    return NULL;
  }

  /* Start network loop. */
  res = mosquitto_loop_start(mosq);
  if (res != MOSQ_ERR_SUCCESS) {
    log_error("Unable to start loop: %s", mosquitto_strerror(res));
    return NULL;
  }

  return mosq;
}

void mqtt_close(struct mosquitto *mosq)
{
  mosquitto_loop_stop(mosq, 1);
  mosquitto_disconnect(mosq);
  mosquitto_destroy(mosq);
  mosquitto_lib_cleanup();
}

int mqtt_publish(struct mosquitto *mosq, const char *topic_prefix, const char *topic_suffix, const void *payload, int qos)
{
  char topic[TOPIC_MAXLEN + 1];
  int res;

  if (topic_prefix != NULL) {
    if (topic_suffix != NULL) {
      sprintf(topic, "%s%s", topic_prefix, topic_suffix);
    } else {
      sprintf(topic, "%s", topic_prefix);
    }
  } else {
    if (topic_suffix != NULL) {
      sprintf(topic, "%s", topic_suffix);
    } else {
      return -1;
    }
  }

  res = mosquitto_publish(mosq, NULL, topic, strlen(payload), payload, qos, 1);
  if (res != 0)
    log_error("Cannot publish topic %s: %s\n", topic, mosquitto_strerror(res));

  return res;
}


const char *mqtt_strerror(int err)
{
  return mosquitto_strerror(err);
}