#include "lib/core/globals.h"
#include "lib/data/fluxmap.h"
#include "lib/data/fluxmapreader.h"
#include "lib/data/fluxpattern.h"
#include "protocol.h"
#include "lib/decoders/decoders.h"
#include "lib/data/sector.h"
#include "f85.h"
#include "lib/core/crc.h"
#include "lib/core/bytes.h"
#include "fmt/format.h"
#include <string.h>
#include <algorithm>

const FluxPattern SECTOR_RECORD_PATTERN(24, F85_SECTOR_RECORD);
const FluxPattern DATA_RECORD_PATTERN(24, F85_DATA_RECORD);
const FluxMatchers ANY_RECORD_PATTERN(
    {&SECTOR_RECORD_PATTERN, &DATA_RECORD_PATTERN});

static int decode_data_gcr(uint8_t gcr)
{
    switch (gcr)
    {
#define GCR_ENTRY(gcr, data) \
    case gcr:                \
        return data;
#include "data_gcr.h"
#undef GCR_ENTRY
    }
    return -1;
}

static Bytes decode(const std::vector<bool>& bits)
{
    Bytes output;
    ByteWriter bw(output);
    BitWriter bitw(bw);

    auto ii = bits.begin();
    while (ii != bits.end())
    {
        uint8_t inputfifo = 0;
        for (size_t i = 0; i < 5; i++)
        {
            if (ii == bits.end())
                break;
            inputfifo = (inputfifo << 1) | *ii++;
        }

        bitw.push(decode_data_gcr(inputfifo), 4);
    }
    bitw.flush();

    return output;
}

class DurangoF85Decoder : public Decoder
{
public:
    DurangoF85Decoder(const DecoderProto& config): Decoder(config) {}

    nanoseconds_t advanceToNextRecord() override
    {
        return seekToPattern(ANY_RECORD_PATTERN);
    }

    void decodeSectorRecord() override
    {
        /* Skip sync bits and ID byte. */

        if (readRaw24() != F85_SECTOR_RECORD)
            return;

        /* Read header. */

        const auto& bytes = decode(readRawBits(6 * 10));

        _sector->logicalSector = bytes[2];
        _sector->logicalSide = 0;
        _sector->logicalTrack = bytes[0];

        uint16_t wantChecksum = bytes.reader().seek(4).read_be16();
        uint16_t gotChecksum = crc16(CCITT_POLY, 0xef21, bytes.slice(0, 4));
        if (wantChecksum == gotChecksum)
            _sector->status =
                Sector::DATA_MISSING; /* unintuitive but correct */
    }

    void decodeDataRecord() override
    {
        /* Skip sync bits ID byte. */

        if (readRaw24() != F85_DATA_RECORD)
            return;

        const auto& bytes = decode(readRawBits((F85_SECTOR_LENGTH + 3) * 10))
                                .slice(0, F85_SECTOR_LENGTH + 3);
        ByteReader br(bytes);

        _sector->data = br.read(F85_SECTOR_LENGTH);
        uint16_t wantChecksum = br.read_be16();
        uint16_t gotChecksum = crc16(CCITT_POLY, 0xbf84, _sector->data);
        _sector->status =
            (wantChecksum == gotChecksum) ? Sector::OK : Sector::BAD_CHECKSUM;
    }
};

std::unique_ptr<Decoder> createDurangoF85Decoder(const DecoderProto& config)
{
    return std::unique_ptr<Decoder>(new DurangoF85Decoder(config));
}
