#ifndef LAYER1_RX_H
#define LAYER1_RX_H

#include <liquid/liquid.h>

#include "modcod.h"
#include "correlator.h"

#include "results.h"

typedef enum {
	RX_STATE_ACQUISITION,
	RX_STATE_HEADER,
	RX_STATE_DATA,
} rx_state_t;


typedef enum {
	RX_EVT_PACKET_RECEIVED,
	RX_EVT_PREAMBLE_FOUND,
	RX_EVT_CHECKSUM_ERROR,
} rx_evt_t;


typedef void (*rx_callback_t)(rx_evt_t evt, uint8_t *packet_data, size_t packet_len);


typedef struct
{
	// NCOs for carrier frequency offset correction
	nco_crcf carrier_coarse_nco;
	nco_crcf carrier_fine_nco;

	// Forward error correction objects
	fec hdr_fec;

	// Demodulators
	modem hdr_demod;
	modem payload_demod;

	// symbol timing synchronizer
	symsync_crcf symsync;

	// preamble correlator
	correlator_ctx_t preamble_correlator;

	// Receiver state
	rx_state_t state;

	// Callback function to notify user of certain events
	rx_callback_t callback;

	// Precalcuated header lengths
	unsigned int hdr_len_symbols;
	unsigned int hdr_len_enc_bytes;

	// Information from the decoded header
	uint16_t payload_len_symbols;
	uint16_t payload_len_bytes;
	uint16_t payload_crc;
	uint16_t payload_len_enc_bytes;
	modcod_t modcod;
} layer1_rx_t;


/*!
 * \brief Initialize the receiver.
 *
 * \param tx         Pointer to the receiver context.
 * \param callback   Function to be called on receiver events.
 * \returns          The result of the initialization.
 */
result_t layer1_rx_init(layer1_rx_t *rx, rx_callback_t callback);


/*!
 * \brief Shut the receiver down. Frees all memory.
 *
 * \param tx    Pointer to the receiver context.
 * \returns     The result of the shutdown.
 */
result_t layer1_rx_shutdown(layer1_rx_t *rx);


/*!
 * \brief Process the given block of samples.
 *
 * Runs the whole receiver chain for the given samples. This includes timing-
 * and frequency synchronization, preamble search, header demodulation and
 * decoding and payload demodulation and decoding.
 *
 * On specific events, most notably when a packet is successfully decoded, the
 * callback function passed to \ref layer1_rx_init() will be called. See \ref
 * rx_evt_t for possible events.
 *
 * \param tx             Pointer to the receiver context.
 * \param samples        Pointer to the samples to process.
 * \param sample_count   Number of samples to process.
 * \returns              The result of the shutdown.
 */
result_t layer1_rx_process(layer1_rx_t *rx, const float complex *samples, size_t sample_count);

#endif // LAYER1_RX_H