// native_bridge/include/INativeInstrument.h
#ifndef I_NATIVE_INSTRUMENT_H
#define I_NATIVE_INSTRUMENT_H

#include <cstdint>
#include <string>

enum class InstrumentType {
    VST3,
    VST2,
    SOUNDFONT_SF2_SF3,
    SFZ
};

class INativeInstrument {
public:
    virtual ~INativeInstrument() = default;

    // Initialize Engine with Sample Rate and Buffer Size
    virtual bool init(double sampleRate, uint32_t maxBlockSize) = 0;

    // Select Bank and Program Change
    virtual void selectProgram(uint32_t channel, uint32_t bank, uint32_t program) = 0;

    // Dispatch MIDI Note On / Note Off events
    virtual void noteOn(uint32_t channel, uint32_t pitch, float velocity, uint32_t sampleOffset) = 0;
    virtual void noteOff(uint32_t channel, uint32_t pitch, uint32_t sampleOffset) = 0;

    // MIDI continuous controllers (A12): CC value, program change, 14-bit pitch bend
    virtual void controlChange(uint32_t channel, uint32_t cc, uint32_t value) = 0;
    virtual void programChange(uint32_t channel, uint32_t program) = 0;
    virtual void pitchBend(uint32_t channel, uint32_t bend14) = 0;

    // Open/close Native GUI window
    virtual bool openGUI(void* parentWindowHandle) = 0;
    // Headless engines (VST2 without an editor, SF2/SFZ): the bridge must
    // not create/reuse a window for them.
    virtual bool canOpenGUI() const { return true; }
    // Sandbox hosts whose child owns its own top-level window (sandbox VST2):
    // the bridge must not create a parent native window nor close other
    // editors — attachView(nullptr) just forwards the OPEN_GUI control.
    virtual bool ownsGuiWindow() const { return false; }
    virtual void closeGUI() = 0;
    // VST3 reopen-after-close: the bridge checks before openGUI whether the
    // instance must be rebuilt; while it is, the engine sets reloading=true
    // and the real-time loop skips processAudioBlock (teardown must not race
    // the audio thread — a reload terminates the VST while renderAll may be
    // inside processAudioBlock on the same instance).
    virtual bool needsReload() const { return false; }
    virtual void setReloading(bool /*on*/) {}
    // VST3: rebuild the plugin instance (terminate + loadPlugin) on the owning
    // apartment thread. The bridge calls it after tearing an editor down so the
    // audio loop never processes an instance whose editor was dropped without
    // view->removed(). Non-VST engines: no-op.
    virtual bool reload() { return true; }
    // VST3: split openGUI so instance teardown/reload runs on the owning
    // apartment thread while view->attached() may run on a temporary thread
    // with the channel worker pumping messages (see bridge main.cpp).
    virtual bool reloadForGUI() { return true; }
    virtual bool attachView(void* /*parentWindowHandle*/) { return false; }
    virtual void resizeView(int /*w*/, int /*h*/) {}
    // Periodic idle tick for attached editors (VST2 effEditIdle repaints;
    // others: no-op). Called on the UI worker's pump loop.
    virtual void guiIdle() {}
    // True while the editor view is attached (GUI window open). The bridge uses
    // it to dedupe repeated OPEN_GUI (frontend retry spam) — re-attaching a
    // view that is already attached corrupts plugins (Nexus createView→null).
    virtual bool hasAttachedView() const { return false; }
    // G0.4: serialize/restore the plugin preset across instance reloads
    // (GUI close/reopen). Non-VST engines: no-op (nothing to save).
    virtual void captureState() {}
    virtual void restoreState() {}
    // G2.1: serialize the current preset to a portable string for the state
    // file (VST3: base64 of captured component+controller state). Caller must
    // call captureState() first (VST3 buffers are refreshed there). Non-VST
    // engines: empty.
    virtual std::string serializeState() const { return std::string(); }
    // G2.3: replace the preset with a previously serialized one (VST3:
    // base64 of [4B BE compLen][component][4B BE ctrlLen][controller]).
    // Must be called after the instrument is loaded. Non-VST: no-op.
    virtual void loadSerializedState(const std::string& /*base64*/) {}
    // G2.1: last bank/program for a MIDI channel (SF2/SF3). Others: 0.
    virtual uint32_t bankOf(uint32_t channel) const { return 0; }
    virtual uint32_t programOf(uint32_t channel) const { return 0; }

    // Real-time Audio PCM Float32 rendering loop
    virtual void processAudioBlock(float* outputL, float* outputR, uint32_t numSamples) = 0;
};

#endif // I_NATIVE_INSTRUMENT_H