Decoder.h

#pragma once

#include "../azaraC_config.h"
#include "../framer/Frame.h"
#include "../Message.h"

namespace azaraC {
namespace internal {

class Decoder {
public:
    bool decode(const Frame& frame, Message& out, uint32_t report_unix = 0);

protected:
    // CRC-24Q (IS-QZSS-L1S §3.2.8)
    static uint32_t crc24q(const uint8_t* data, uint16_t bit_len);

    // Date conversion helpers (civil date <-> days since 1970-01-01)
    static void civil_from_days(uint32_t days_since_1970, uint32_t& y, uint32_t& m, uint32_t& d);
    static uint32_t days_from_civil(uint32_t y, uint32_t m, uint32_t d);

    // Bit extraction helpers (MSB-first, 0-indexed from frame start)
    uint32_t getBits(const uint8_t* buf, uint16_t start, uint8_t len);
    uint64_t getBits64(const uint8_t* buf, uint16_t start, uint8_t len);

    // LatLon from 41-bit field (lat_ns:1, lat_d:7, lat_m:6, lat_s:6, lon_ew:1, lon_d:8, lon_m:6, lon_s:6)
    LatLon  extractLatLon(const uint8_t* buf, uint16_t start);

    // day(5)+hour(5)+min(6)=16 bit sub-field -> TimeFields
    // report_unix: UNIX time from GPS module (recommended) or SNTP, 0 = unresolved
    TimeFields extractDHM(const uint8_t* buf, uint16_t start, uint32_t report_unix);

    // Resolve TimeFields from components using report_unix as baseline.
    // report_unix < 2000-01-01 → unix_time = 0 (unresolved).
    static TimeFields resolveTime(uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint32_t report_unix);

    // Resolve 12-bit arrival time (day_offset:1, hour:5, min:6) into TimeFields
    static TimeFields resolveArrivalTime(uint16_t raw, uint32_t base_unix);

    // Read up to 3 notification codes (9 bits each) starting at bit offset
    uint8_t readNotifications(const uint8_t* b, uint16_t start, uint16_t* notification);

#if (AZARAC_ENABLE_DCX_CAMF)
    bool decodeDcx(const uint8_t* bits, Message& out, uint32_t report_unix);
#endif

    bool decodeQzqsm(const uint8_t* bits, Message& out, uint32_t report_unix);

    // OOB flag: set by getBits/getBits64 on reads beyond the 256-bit frame
    // boundary. decode() clears it per session and fails if OOB is detected.
    bool oob_ = false;

    // MT=43 JMA sub-decoders. Declarations unconditional: guards on the
    // definitions control code size; decodeQzqsm() dispatches via the shared
    // AZARAC_DC_CATEGORIES table (constant-folded guards, disabled never called).
    void decodeEEW(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeHypocenter(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeSeismic(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeNankai(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeTsunami(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeNwPacTsu(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeVolcano(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeAshFall(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeWeather(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeFlood(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeTyphoon(const uint8_t* b, Message& out, uint32_t report_unix);
    void decodeMarine(const uint8_t* b, Message& out, uint32_t report_unix);
};

} // namespace internal
} // namespace azaraC