/* Copyright (c) 2015 Nordic Semiconductor. All Rights Reserved.
 *
 * The information contained herein is property of Nordic Semiconductor ASA.
 * Terms and conditions of usage are described in detail in NORDIC
 * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
 *
 * Licensees are granted free, non-transferable use of the information. NO
 * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
 * the file.
 *
 */

/** @file
 *
 * @defgroup app_mailbox Mailbox library
 * @{
 * @ingroup app_common
 *
 * @brief Mailbox for safely queuing items.
 *
 */

#ifndef _APP_MAILBOX_H
#define _APP_MAILBOX_H

#include <stdint.h>
#include "sdk_errors.h"
#include "app_util.h"
#include "nordic_common.h"

/**
 * @brief Supported overflow modes.
 */
typedef enum
{
    APP_MAILBOX_MODE_NO_OVERFLOW, //!< If the mailbox is full, @ref app_mailbox_put does not add a new element.
    APP_MAILBOX_MODE_OVERFLOW     //!< If the mailbox is full, the oldest element is lost and a new one is added.
} app_mailbox_overflow_mode_t;

#include "app_mailbox_local.h"

/**
 * @brief Mailbox definition structure.
 */
typedef struct
{
  void                      * p_pool;    /**< Memory array for mail. */
  app_mailbox_cb_t          * p_cb;      /**< Mailbox handle. */
  uint16_t                    item_sz;  /**< Size of a single item. */
  uint8_t                     queue_sz; /**< Capacity of the queue. */
} app_mailbox_t;

/**
 * @brief Macro to statically allocate memory for a given mailbox queue.
 */
#define APP_MAILBOX_DEF(name, QUEUE_SZ, ITEM_SZ)                                            \
static uint32_t         STRING_CONCATENATE(mailbox_items_,name)[(1+CEIL_DIV((ITEM_SZ),4))*(QUEUE_SZ)];\
static app_mailbox_cb_t STRING_CONCATENATE(mailbox_cb_,name);                                         \
const app_mailbox_t name =                                                                  \
    {                                                                                       \
        .p_pool   = STRING_CONCATENATE(mailbox_items_,name),                                          \
        .p_cb     = STRING_CONCATENATE(&mailbox_cb_,name),                                            \
        .queue_sz = (uint8_t)(QUEUE_SZ),                                                    \
        .item_sz  = (uint16_t)(ITEM_SZ),                                                    \
    }

/**
 * @brief Function for creating a mailbox queue.
 *
 * This function creates and initializes a mailbox queue.
 *
 * @param[in]  p_mailbox  Pointer to the mailbox.
 *
 * @retval NRF_SUCCESS              If the queue was successfully created.
 */
ret_code_t app_mailbox_create(const app_mailbox_t * p_mailbox);

/**
 * @brief Function for putting an item in the mailbox queue.
 *
 * @param[in] p_mailbox   Pointer to the mailbox.
 * @param[in] p_item      Pointer to the item to be queued.
 *
 * @retval NRF_SUCCESS              If the item was enqueued.
 * @retval NRF_ERROR_NO_MEM         If the queue is full.
 */
ret_code_t app_mailbox_put (const app_mailbox_t * p_mailbox, void * p_item);

/**
 * @brief Function for putting an item with a specified size in the mailbox queue.
 *
 * @param[in] p_mailbox   Pointer to the mailbox.
 * @param[in] p_item      Pointer to the item to be queued.
 * @param[in] size        Size of the item.
 *
 * @retval NRF_SUCCESS              If the item was enqueued.
 * @retval NRF_ERROR_NO_MEM         If the queue is full.
 */
ret_code_t app_mailbox_sized_put (const app_mailbox_t * p_mailbox, void * p_item, uint16_t size);

/**
 * @brief Function for getting an item from the mailbox queue.
 *
 * @param[in]  p_mailbox   Pointer to the mailbox.
 * @param[out] p_item      Pointer to the output location for the dequeued item.
 *
 * @retval NRF_SUCCESS              If the item was retrieved successfully.
 * @retval NRF_ERROR_NO_MEM         If the queue is empty.
 */
ret_code_t app_mailbox_get (const app_mailbox_t * p_mailbox, void * p_item);

/**
 * @brief Function for getting an item and its size from the mailbox queue.
 *
 * @param[in]  p_mailbox   Pointer to the mailbox.
 * @param[out] p_item      Pointer to the output location for the dequeued item.
 * @param[out] p_size      Pointer to the item size.
 *
 * @retval NRF_SUCCESS              If the item was retrieved successfully.
 * @retval NRF_ERROR_NO_MEM         If the queue is empty.
 */
ret_code_t app_mailbox_sized_get (const app_mailbox_t * p_mailbox, void * p_item, uint16_t * p_size);

/**
 * @brief Function for getting the current length of the mailbox queue.
 *
 * @param[in]  p_mailbox   Pointer to the mailbox.
 *
 * @return Current number of elements in the queue.
 *
 */
uint32_t app_mailbox_length_get (const app_mailbox_t * p_mailbox);

/**
 * @brief Function for changing the mode of overflow handling.
 *
 * @param[in]  p_mailbox   Pointer to the mailbox.
 * @param mode             New mode to set.
 */
void app_mailbox_mode_set(const app_mailbox_t * p_mailbox, app_mailbox_overflow_mode_t mode);

#endif //_APP_MAILBOX_H
/** @} */
