#ifndef QUEUE_H
#define QUEUE_H

#include "command.h"
#include <stdbool.h>

/* Fixed‑size lock‑free SPSC queue (single producer, single consumer).
 * The queue is safe for one thread writing (producer) and one thread
 * reading (consumer).  No locks, no dynamic memory allocation.
 * Must be initialised before first use.  All operations are RT‑safe. */

#define QUEUE_CAPACITY 256

typedef struct {
    command_t  buffer[QUEUE_CAPACITY];
    /* head: index where next element will be written (producer only)
     * tail: index of next element to read (consumer only) */
    int head;
    int tail;
} spsc_queue_t;

/* Initialise queue (must be called once before any push/pop). */
void queue_init(spsc_queue_t *q);

/* Push a command.  Returns true on success, false if queue full. */
bool queue_push(spsc_queue_t *q, command_t cmd);

/* Pop a command.  Returns true if a command was retrieved, false if empty. */
bool queue_pop(spsc_queue_t *q, command_t *cmd);

#endif