/**
 * @file
 * Prototypes and structures for the ring buffer module.
 */

#ifndef __RINGBUFFER_H__
#define __RINGBUFFER_H__

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>

/**
 * The size of a ring buffer.
 * Due to the design only <tt> RING_BUFFER_SIZE-1 </tt> items
 * can be contained in the buffer.
 * The buffer size must be a power of two.
 */
// #define RING_BUFFER_SIZE     256U//512
//
// #if (RING_BUFFER_SIZE & (RING_BUFFER_SIZE - 1)) != 0
// #error "RING_BUFFER_SIZE must be a power of two"
// #endif

/**
 * The type which is used to hold the size
 * and the indicies of the buffer.
 * Must be able to fit \c RING_BUFFER_SIZE .
 */
typedef uint32_t ring_buffer_size_t;

/**
 * Used as a modulo operator
 * as <tt> a % b = (a & (b − 1)) </tt>
 * where \c a is a positive index in the buffer and
 * \c b is the (power of two) size of the buffer.
 */
// #define RING_BUFFER_MASK (RING_BUFFER_SIZE-1)

/**
 * Structure which holds a ring buffer.
 * The buffer contains a buffer array
 * as well as metadata for the ring buffer.
 */
typedef struct ring_buffer
{
    /** Buffer memory. */
    uint8_t *buffer;
    /** Buffer size. */
    ring_buffer_size_t size;
    /** Index of tail. */
    ring_buffer_size_t tail_index;
    /** Index of head. */
    ring_buffer_size_t head_index;
    /** Rx Locker. */
    bool rx_lock;
} ring_buffer_t;
// typedef struct ring_buffer {
//  /** Buffer memory. */
////  uint8_t *buffer;
//  unsigned char buffer[RING_BUFFER_SIZE];
//  /** Index of tail. */
//  ring_buffer_size_t tail_index;
//  /** Index of head. */
//  ring_buffer_size_t head_index;
//  /** Rx Locker. */
//  bool rx_lock;
//}ring_buffer_t;

// typedef struct ring_buffer {
//  /** Buffer memory. */
////  uint8_t *buffer;
//  unsigned char buffer[RING_BUFFER_SIZE];
//  /** Index of tail. */
//  ring_buffer_size_t tail_index;
//  /** Index of head. */
//  ring_buffer_size_t head_index;
//  /** Rx Locker. */
//  bool rx_lock;
//}ring_buffer_t;

/**
 * Initializes the ring buffer pointed to by <em>buffer</em>.
 * This function can also be used to empty/reset the buffer.
 * @param buffer The ring buffer to initialize.
 */
// void ring_buffer_init(ring_buffer_t *buffer);
void ring_buffer_create(ring_buffer_t *rb, uint8_t *buffer, uint32_t size);

/**
 * Adds a byte to a ring buffer.
 * @param buffer The buffer in which the data should be placed.
 * @param data The byte to place.
 */
void ring_buffer_queue(ring_buffer_t *rb, uint8_t data);

/**
 * Adds an array of bytes to a ring buffer.
 * @param buffer The buffer in which the data should be placed.
 * @param data A pointer to the array of bytes to place in the queue.
 * @param size The size of the array.
 */
void ring_buffer_queue_arr(ring_buffer_t *rb, uint8_t *data,
                           ring_buffer_size_t size);

/**
 * Returns the oldest byte in a ring buffer.
 * @param buffer The buffer from which the data should be returned.
 * @param data A pointer to the location at which the data should be placed.
 * @return 1 if data was returned; 0 otherwise.
 */
ring_buffer_size_t ring_buffer_dequeue(ring_buffer_t *rb, uint8_t *data);

/**
 * Returns the <em>len</em> oldest bytes in a ring buffer.
 * @param buffer The buffer from which the data should be returned.
 * @param data A pointer to the array at which the data should be placed.
 * @param len The maximum number of bytes to return.
 * @return The number of bytes returned.
 */
ring_buffer_size_t ring_buffer_dequeue_arr(ring_buffer_t *rb, uint8_t *data,
                                           ring_buffer_size_t len);
/**
 * Peeks a ring buffer, i.e. returns an element without removing it.
 * @param buffer The buffer from which the data should be returned.
 * @param data A pointer to the location at which the data should be placed.
 * @param index The index to peek.
 * @return 1 if data was returned; 0 otherwise.
 */
ring_buffer_size_t ring_buffer_peek(ring_buffer_t *rb, uint8_t *data,
                                    ring_buffer_size_t index);

/**
 * Returns whether a ring buffer is empty.
 * @param buffer The buffer for which it should be returned whether it is empty.
 * @return 1 if empty; 0 otherwise.
 */
inline ring_buffer_size_t ring_buffer_is_empty(ring_buffer_t *rb)
{
    return (rb->head_index == rb->tail_index);
}

/**
 * Returns whether a ring buffer is full.
 * @param buffer The buffer for which it should be returned whether it is full.
 * @return 1 if full; 0 otherwise.
 */
inline ring_buffer_size_t ring_buffer_is_full(ring_buffer_t *rb)
{
    return ((rb->head_index - rb->tail_index) & (rb->size - 1)) ==
           (rb->size - 1);
}

/**
 * Returns the number of items in a ring buffer.
 * @param buffer The buffer for which the number of items should be returned.
 * @return The number of items in the ring buffer.
 */
inline ring_buffer_size_t ring_buffer_num_items(ring_buffer_t *rb)
{
    return ((rb->head_index - rb->tail_index) & (rb->size - 1));
}

#endif /* __RINGBUFFER_H__ */