//--------------------------------------------------------------------
// M17 C library - m17.h
//
// Wojciech Kaczmarski, SP5WWP
// M17 Project, 29 December 2023
//--------------------------------------------------------------------
#pragma once

#ifdef __cplusplus
extern "C" {
#endif
#include <stdint.h>
#include <stddef.h>

// M17 C library - lib/lib.c
#define BSB_SPS             10                      //samples per symbol
#define FLT_SPAN            8                       //baseband RRC filter span in symbols
#define SYM_PER_SWD         8                       //symbols per syncword
#define SW_LEN              (BSB_SPS*SYM_PER_SWD)   //syncword detector length
#define SYM_PER_PLD         184                     //symbols per payload in a frame
#define SYM_PER_FRA         192                     //symbols per whole 40 ms frame
#define RRC_DEV             7168.0f                 //.rrc file deviation for +1.0 symbol

// M17 C library - lib/payload/call.c
#define CHAR_MAP " ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/."

void decode_callsign_bytes(uint8_t *outp, const uint8_t inp[6]);
void decode_callsign_value(uint8_t *outp, const uint64_t inp);
int8_t encode_callsign_bytes(uint8_t out[6], const uint8_t *inp);
int8_t encode_callsign_value(uint64_t *out, const uint8_t *inp);

// M17 C library - preamble
/**
 * @brief Preamble type (0 for LSF, 1 for BERT).
 */
typedef enum
{
	PREAM_LSF,
	PREAM_BERT
} pream_t;

// M17 C library - frame type
/**
 * @brief Frame type (0 - LSF, 1 - stream, 2 - packet).
 */
typedef enum
{
	FRAME_LSF,
	FRAME_STR,
	FRAME_PKT
} frame_t;

// M17 C library - payload
/**
 * @brief Structure holding Link Setup Frame data.
 */
typedef struct
{
	uint8_t dst[6];
	uint8_t src[6];
	uint8_t type[2];
	uint8_t meta[112/8];
	uint8_t crc[2];
} lsf_t;

// M17 C library - high level functions
void send_preamble(float out[SYM_PER_FRA], uint32_t* cnt, const pream_t type);
void send_syncword(float out[SYM_PER_SWD], uint32_t* cnt, const uint16_t syncword);
void send_data(float out[SYM_PER_PLD], uint32_t* cnt, const uint8_t* in);
void send_eot(float out[SYM_PER_FRA], uint32_t* cnt);
void send_frame(float out[SYM_PER_FRA], const uint8_t* data, const frame_t type, const lsf_t* lsf, const uint8_t lich_cnt, const uint16_t fn);

// M17 C library - lib/encode/convol.c
extern const uint8_t puncture_pattern_1[61];
extern const uint8_t puncture_pattern_2[12];
extern const uint8_t puncture_pattern_3[8];

void conv_encode_stream_frame(uint8_t* out, const uint8_t* in, const uint16_t fn);
void conv_encode_packet_frame(uint8_t* out, const uint8_t* in);
void conv_encode_LSF(uint8_t* out, const lsf_t* in);

// M17 C library - lib/payload/crc.c
//M17 CRC polynomial
extern const uint16_t M17_CRC_POLY;

uint16_t CRC_M17(const uint8_t* in, const uint16_t len);
uint16_t LSF_CRC(const lsf_t* in);

// M17 C library - lib/payload/lich.c
void extract_LICH(uint8_t outp[6], const uint8_t cnt, const lsf_t* inp);
void unpack_LICH(uint8_t* out, const uint8_t in[12]);

// M17 C library - lib/math/golay.c
extern const uint16_t encode_matrix[12];
extern const uint16_t decode_matrix[12];

uint32_t golay24_encode(const uint16_t data);
uint16_t golay24_sdecode(const uint16_t codeword[24]);
void decode_LICH(uint8_t outp[6], const uint16_t inp[96]);
void encode_LICH(uint8_t outp[12], const uint8_t inp[6]);

// M17 C library - lib/phy/interleave.c
//interleaver pattern
extern const uint16_t intrl_seq[SYM_PER_PLD*2];

void reorder_bits(uint8_t outp[SYM_PER_PLD*2], const uint8_t inp[SYM_PER_PLD*2]);
void reorder_soft_bits(uint16_t outp[SYM_PER_PLD*2], const uint16_t inp[SYM_PER_PLD*2]);

// M17 C library - lib/math/math.c
uint16_t q_abs_diff(const uint16_t v1, const uint16_t v2);
float eucl_norm(const float* in1, const int8_t* in2, const uint8_t n);
void int_to_soft(uint16_t* out, const uint16_t in, const uint8_t len);
uint16_t soft_to_int(const uint16_t* in, const uint8_t len);
uint16_t div16(const uint16_t a, const uint16_t b);
uint16_t mul16(const uint16_t a, const uint16_t b);
uint16_t soft_bit_XOR(const uint16_t a, const uint16_t b);
uint16_t soft_bit_NOT(const uint16_t a);
void soft_XOR(uint16_t* out, const uint16_t* a, const uint16_t* b, const uint8_t len);

// M17 C library - lib/phy/randomize.c
//randomizing pattern
extern const uint8_t rand_seq[46];

void randomize_bits(uint8_t inp[SYM_PER_PLD*2]);
void randomize_soft_bits(uint16_t inp[SYM_PER_PLD*2]);

// M17 C library - lib/phy/slice.c
void slice_symbols(uint16_t out[2*SYM_PER_PLD], const float inp[SYM_PER_PLD]);

// M17 C library - lib/math/rrc.c
//sample RRC filter for 48kHz sample rate
//alpha=0.5, span=8, sps=10, gain=sqrt(sps)
extern const float rrc_taps_10[8*10+1];

//sample RRC filter for 24kHz sample rate
//alpha=0.5, span=8, sps=5, gain=sqrt(sps)
extern const float rrc_taps_5[8*5+1];

// M17 C library - lib/encode/symbols.c
// dibits-symbols map (TX)
extern const int8_t symbol_map[4];
extern const int8_t symbol_list[4];

// M17 C library - lib/phy/sync.c
//syncwords
extern const uint16_t SYNC_LSF;
extern const uint16_t SYNC_STR;
extern const uint16_t SYNC_PKT;
extern const uint16_t SYNC_BER;
extern const uint16_t EOT_MRKR;

// M17 C library - lib/decode/viterbi.c
#define K			        5                       //constraint length
#define NUM_STATES	        (1 << (K - 1))          //number of states

uint32_t viterbi_decode(uint8_t* out, const uint16_t* in, const uint16_t len);
uint32_t viterbi_decode_punctured(uint8_t* out, const uint16_t* in, const uint8_t* punct, const uint16_t in_len, const uint16_t p_len);
void viterbi_decode_bit(uint16_t s0, uint16_t s1, size_t pos);
uint32_t viterbi_chainback(uint8_t* out, size_t pos, const uint16_t len);
void viterbi_reset(void);

//End of Transmission symbol pattern
extern const float eot_symbols[8];

// M17 C library - decode/symbols.c
// syncword patterns (RX)
// TODO: Compute those at runtime from the consts below
extern const int8_t lsf_sync_symbols[8];
extern const int8_t str_sync_symbols[8];
extern const int8_t pkt_sync_symbols[8];

// symbol levels (RX)
extern const float symbol_levels[4];

#ifdef __cplusplus
}
#endif