/**
 * @file radio.h
 * @brief RADIO peripheral driver -- NRF_1Mbit proprietary mode.
 */
#pragma once
#include <stdbool.h>
#include <stdint.h>

/**
 * @brief PTT packet transmitted on every FHSS hop.
 *
 * The receiver uses @p slot to resynchronise its FHSS counter after
 * receiving the first packet.
 */
typedef struct __attribute__((packed)) {
    uint32_t slot; /**< Sender's FHSS slot number at time of transmission. */
    uint8_t flags; /**< Bitmask: PTT_FLAG_ACTIVE when voice channel is open. */
} ptt_frame_t;

#define PTT_FLAG_ACTIVE 0x01u /**< PTT button is held on the transmitting side. */

/** @brief Configure the RADIO peripheral (mode, packet format, address, CRC, power). */
void radio_init(void);

/**
 * @brief Set the RF channel.
 * @param ch Channel index 0-39, maps to 2400+ch MHz (MAP=0).
 */
void radio_set_channel(uint8_t ch);

/**
 * @brief Transmit one packet synchronously.
 *
 * Loads @p data into the internal packet buffer, asserts TASKS_TXEN, and
 * returns after EVENTS_END fires.  RADIO is DISABLED automatically via the
 * END_DISABLE shortcut before the function returns.
 *
 * @param data  Payload bytes.
 * @param len   Payload length (0-255 bytes).
 */
void radio_tx(const uint8_t *data, uint8_t len);

/**
 * @brief Transmit one FHSS hop: advance channel, send PTT frame, hold dwell time.
 *
 * Call repeatedly in a loop while the PTT button is held.  Each call occupies
 * exactly FHSS_DWELL_MS milliseconds.
 */
void radio_tx_burst(void);

/**
 * @brief Receive one FHSS hop: advance channel, listen for FHSS_DWELL_MS ms.
 *
 * If a packet with a valid CRC arrives during the dwell window, @p frame_out
 * is filled and the function returns true.  The caller should then call
 * fhss_set_slot(frame_out->slot + 1) to synchronise the hopping sequence.
 *
 * @param frame_out  Destination for the received frame (must not be NULL).
 * @return true if a valid packet was received, false on timeout or CRC error.
 */
bool radio_rx_burst(ptt_frame_t *frame_out);