#ifndef MQTT_H_
#define MQTT_H_

#include <stdint.h>
#include <stdbool.h>
#include "esp_err.h"

/**
 * @file mqtt.h
 * @brief MQTT configuration and control interface.
 *
 * This module provides initialization, configuration,
 * and runtime access functions for the MQTT client.
 *
 * Configuration is persisted in NVS under namespace "mqtt".
 */

/* -------------------------------------------------------------------------- */
/*                                Definitions                                 */
/* -------------------------------------------------------------------------- */

#define MQTT_MAX_SERVER_LEN 64     /**< Max length for MQTT server URI */
#define MQTT_MAX_USER_LEN 32       /**< Max length for MQTT username */
#define MQTT_MAX_PASSWORD_LEN 64   /**< Max length for MQTT password */
#define MQTT_MAX_BASE_TOPIC_LEN 64 /**< Max length for MQTT base topic */

/* -------------------------------------------------------------------------- */
/*                              Public Functions                              */
/* -------------------------------------------------------------------------- */

/**
 * @brief Initialize MQTT subsystem.
 *
 * Loads configuration from NVS and starts background publish task
 * if MQTT is enabled. Must be called once during system startup.
 */
void mqtt_init(void);

/**
 * @brief Restart the MQTT client safely.
 *
 * Stops the current MQTT client (if running) and starts a new one
 * with the configuration currently stored in NVS.
 *
 * Useful when changing Wi-Fi networks, credentials, or broker settings.
 *
 * @return ESP_OK on success, or an ESP_ERR_* code otherwise.
 */
esp_err_t mqtt_restart(void);

/**
 * @brief Set and persist MQTT configuration parameters in NVS.
 *
 * Any NULL parameter will be skipped (the previous value remains stored).
 *
 * @param enabled       Whether MQTT should be enabled (true/false).
 * @param server        Broker URI (e.g. "mqtt://192.168.1.10").
 * @param base_topic    Base topic prefix for publish/subscribe.
 * @param user          MQTT username (optional).
 * @param password      MQTT password (optional).
 * @param periodicity   Publish interval (in seconds). Must be >0 when enabled.
 *
 * @return ESP_OK on success, or an ESP_ERR_* code otherwise.
 */
esp_err_t mqtt_set_config(bool enabled,
                          const char *server,
                          const char *base_topic,
                          const char *user,
                          const char *password,
                          uint16_t periodicity);

/**
 * @brief Get whether MQTT is enabled.
 *
 * @return true if enabled, false otherwise.
 */
bool mqtt_get_enabled(void);

/**
 * @brief Get MQTT broker URI stored in NVS.
 *
 * @param[out] value Buffer to receive the URI (min length: MQTT_MAX_SERVER_LEN).
 */
void mqtt_get_server(char *value);

/**
 * @brief Get MQTT base topic stored in NVS.
 *
 * @param[out] value Buffer to receive the base topic (min length: MQTT_MAX_BASE_TOPIC_LEN).
 */
void mqtt_get_base_topic(char *value);

/**
 * @brief Get MQTT username stored in NVS.
 *
 * @param[out] value Buffer to receive the username (min length: MQTT_MAX_USER_LEN).
 */
void mqtt_get_user(char *value);

/**
 * @brief Get MQTT password stored in NVS.
 *
 * @param[out] value Buffer to receive the password (min length: MQTT_MAX_PASSWORD_LEN).
 */
void mqtt_get_password(char *value);

/**
 * @brief Get MQTT publish periodicity in seconds.
 *
 * @return Publish interval in seconds (default: 30).
 */
uint16_t mqtt_get_periodicity(void);

#endif /* MQTT_H_ */