//
// Created by bruno on 13. 7. 2026.
//

#ifndef AUDIOCODER_DECODER_H
#define AUDIOCODER_DECODER_H

#define DECODER_SAMPLE_HISTORY 262144
#define MAX_FSK_TONES 32
#include <SDL_audio.h>
#include <SDL_render.h>
#include <stdint.h>

#include "goertzel.h"

typedef enum
{
    RX_SEARCH,
    RX_SYNC,
    RX_MAGIC,
    RX_DATA
} RxState;

typedef enum
{
        PKT_WAIT_PREAMBLE,
        PKT_WAIT_MAGIC,
        PKT_WAIT_LENGTH,
        PKT_WAIT_DATA,
        PKT_WAIT_CRC1,
        PKT_WAIT_CRC2
    } PacketState;

typedef struct {

    uint8_t bitsPerSymbol;
    uint8_t toneCount;

    uint16_t startFreq;
    uint16_t endFreq;
    uint16_t dataSpacing;

    uint16_t clock0;
    uint16_t clock1;

    uint8_t magicBuffer[16];
    uint32_t magicIndex;
    uint32_t preambleCount;

    uint8_t lostClockCount;
    uint8_t goodClockCount;


    uint32_t symbolSamples;
    uint32_t sampleRate;

    uint32_t sampleCount;

    float sampleHistory[DECODER_SAMPLE_HISTORY];
    uint32_t sampleHistoryWrite;
    uint32_t sampleHistoryCount;
    uint64_t totalSamples;

    Goertzel tones[MAX_FSK_TONES + 2];

    float energies[MAX_FSK_TONES + 2];

    uint8_t currentByte;
    uint8_t bitIndex;

    uint8_t buffer[1024*1024*8];

    uint32_t bufferSize;

    bool lastClock;


    float maxEnergy;
    float clockEnergy0;
    float clockEnergy1;
    float clockRatio;
    uint8_t lastDecodedByte;
    int bestSyncScore;
    int bestSyncPhase;

    RxState rxState;
    PacketState packetState;


    bool expectedClock;
    float lastClockEnergy;
    uint32_t goodClocks;
    uint32_t syncIndex;
    uint32_t badClocks;

    uint64_t phaseSearchStart;
    uint32_t phaseWait;
    int phaseOffset;
    bool phaseSearchReady;

    uint32_t searchOffset;
    uint32_t syncOffset;
    uint8_t clockHistory;
    uint8_t clockCount;

    bool locked;

    SDL_Renderer *renderer;

} Decoder;



void decoder_init(
        Decoder *dec
);


void decoder_process(
        Decoder *dec,
        float *samples,
        uint32_t count
);

void decoder_rebuild_tones(
        Decoder *dec
);

extern Decoder decoder;
extern SDL_AudioDeviceID inputDev;
extern const uint8_t syncBytes[4];

// Internal audio bus for loopback
#define INTERNAL_BUFFER_SIZE 262144
extern float internalBusSamples[INTERNAL_BUFFER_SIZE];
extern volatile uint32_t internalBusWrite;
extern volatile uint32_t internalBusRead;

void initAudioDecoder(SDL_Renderer *renderer);
void decoder_reset_rx(Decoder *dec);

#endif //AUDIOCODER_DECODER_H