#ifndef DECODER_H
#define DECODER_H

/**
 * @todo write docs
 */
#include <deque>

#include <emscripten/val.h>
#include "mad.h"

#define GLUE_LENGTH 6000

class Decoder {
public:
    Decoder();
    ~Decoder();
    
    void addFragment(const emscripten::val& array);
    emscripten::val decode(uint32_t count = UINT32_MAX);
    bool hasMore() const;
    uint32_t framesLeft(uint32_t max = UINT32_MAX);
    
private:
    
    enum State {
        empty,
        onBufferHalf,
        onBufferFull,
        onGlueHalf,
        onGlueFull
    };
    
    struct RawBuffer {
        uint8_t* ptr;
        uint32_t length;
    };
    
    State state;
    
    uint32_t sampleRate;
    uint8_t channels;
    uint32_t cachedLength;
    uint16_t samplesPerFrame;
    uint8_t* glue;
    uint8_t const* cachedNext;
    uint8_t const* cachedThis;
    mad_error cachedError;
    bool cached;
    
    mad_synth* synth;
    mad_stream* stream;
    mad_frame* frame;
    emscripten::val context;
    
    std::deque<RawBuffer> pending;
    
private:
    void pullBuffer();
    void changeBuffer();
    void prepareNextBuffer();
    void initializeProbe(mad_stream& probe);
    void switchToGlue();
    void switchBuffer(uint8_t* bufferPtr, uint32_t length);
};

#endif // DECODER_H