/**
 * @file csi_collector.h
 * @brief CSI data collection and ADR-018 binary frame serialization.
 */

#ifndef CSI_COLLECTOR_H
#define CSI_COLLECTOR_H

#include <stdint.h>
#include <stddef.h>
#include "esp_wifi_types.h"

/** ADR-018 magic number. */
#define CSI_MAGIC 0xC5110001

/** ADR-018 header size in bytes. */
#define CSI_HEADER_SIZE 20

/** Maximum frame buffer size (header + 4 antennas * 256 subcarriers * 2 bytes). */
#define CSI_MAX_FRAME_SIZE (CSI_HEADER_SIZE + 4 * 256 * 2)

/**
 * Initialize CSI collection.
 * Registers the WiFi CSI callback.
 */
void csi_collector_init(void);

/**
 * Serialize CSI data into ADR-018 binary frame format.
 *
 * @param info   WiFi CSI info from the ESP-IDF callback.
 * @param buf    Output buffer (must be at least CSI_MAX_FRAME_SIZE bytes).
 * @param buf_len Size of the output buffer.
 * @return Number of bytes written, or 0 on error.
 */
size_t csi_serialize_frame(const wifi_csi_info_t *info, uint8_t *buf, size_t buf_len);

#endif /* CSI_COLLECTOR_H */