// native_bridge/include/NativeInstrumentEngine.h
#ifndef NATIVE_INSTRUMENT_ENGINE_H
#define NATIVE_INSTRUMENT_ENGINE_H

#include "INativeInstrument.h"

#include <sfizz.hpp>

#include <map>
#include <mutex>
#include <memory>
#include <string>
#include <vector>

// FluidSynth (.sf2 / .sf3)
class FluidSynthInstrument : public INativeInstrument {
public:
    FluidSynthInstrument();
    ~FluidSynthInstrument() override;

    bool loadSoundFontFile(const std::string& path, double sampleRate);

    bool init(double sampleRate, uint32_t maxBlockSize) override;
    void selectProgram(uint32_t channel, uint32_t bank, uint32_t program) override;
    void noteOn(uint32_t channel, uint32_t pitch, float velocity, uint32_t sampleOffset) override;
    void noteOff(uint32_t channel, uint32_t pitch, uint32_t sampleOffset) override;
    void controlChange(uint32_t channel, uint32_t cc, uint32_t value) override;
    void programChange(uint32_t channel, uint32_t program) override;
    void pitchBend(uint32_t channel, uint32_t bend14) override;
    bool openGUI(void* parentWindowHandle) override;
    void closeGUI() override;
    void processAudioBlock(float* outputL, float* outputR, uint32_t numSamples) override;

private:
    void* settings; // fluid_settings_t*
    void* synth;    // fluid_synth_t*
    int sfontId;
    // Per-channel bank select (CC0<<7 | CC32) — programChange phai dung bank
    // that (truoc day hardcode bank 0 -> preset o bank != 0 khong chon duoc).
    uint32_t bank_[16];
};

// sfizz (.sfz)
class SfizzInstrument : public INativeInstrument {
public:
    bool loadSfzFile(const std::string& path, double sampleRate);

    bool init(double sampleRate, uint32_t maxBlockSize) override;
    void selectProgram(uint32_t channel, uint32_t bank, uint32_t program) override;
    void noteOn(uint32_t channel, uint32_t pitch, float velocity, uint32_t sampleOffset) override;
    void noteOff(uint32_t channel, uint32_t pitch, uint32_t sampleOffset) override;
    void controlChange(uint32_t channel, uint32_t cc, uint32_t value) override;
    void programChange(uint32_t channel, uint32_t program) override;
    void pitchBend(uint32_t channel, uint32_t bend14) override;
    bool openGUI(void* parentWindowHandle) override;
    void closeGUI() override;
    void processAudioBlock(float* outputL, float* outputR, uint32_t numSamples) override;

private:
    sfz::Sfizz sfizzSynth;
};

// Multi-instrument host (A10): one engine instance per MIDI channel, so two
// tracks can play two different soundfonts/VSTs simultaneously. All channels
// render into the same output block (mixed), keyed by evt.channel.
class InstrumentEngineManager {
public:
    // Create (or replace) the instrument on `channel` for `path`.
    // Returns false if the type is unsupported or the file fails to load.
    bool assign(uint32_t channel, InstrumentType type, const std::string& path,
                double sampleRate, uint32_t blockSize);

    INativeInstrument* get(uint32_t channel);

    // Mark a channel as rebuilding its VST instance (GUI reopen): the
    // real-time loop then skips processAudioBlock for that channel so VST
    // teardown never races the audio thread.
    void setReloading(uint32_t channel, bool on);

    // Flush every sounding note on every assigned channel.
    void allNotesOff();

    // Zero L/R then sum each assigned instrument into it.
    void renderAll(float* outputL, float* outputR, uint32_t numSamples);

    size_t count() const { std::lock_guard<std::mutex> lock(mu_); return channels_.size(); }

private:
    static std::unique_ptr<INativeInstrument> create_instrument(InstrumentType type);

    mutable std::mutex mu_;
    std::map<uint32_t, std::unique_ptr<INativeInstrument>> channels_;
    // Per-instrument scratch so engines that overwrite (not mix) stay additive.
    std::vector<float> scratchL_, scratchR_;
};

#endif // NATIVE_INSTRUMENT_ENGINE_H
