G2.1: save full instrument state to disk (path/type/preset/transport)

native_bridge/include/NativeInstrumentEngine.h

@@ -3,6 +3,7 @@
 #define NATIVE_INSTRUMENT_ENGINE_H
 
 #include "INativeInstrument.h"
+#include "StateStore.h"
 
 #include <sfizz.hpp>
 
@@ -31,6 +32,9 @@ public:
     void pitchBend(uint32_t channel, uint32_t bend14) override;
     bool openGUI(void* parentWindowHandle) override;
     void closeGUI() override;
+    // G2.1: expose last bank/program for the state snapshot.
+    uint32_t bankOf(uint32_t channel) const override;
+    uint32_t programOf(uint32_t channel) const override;
     void processAudioBlock(float* outputL, float* outputR, uint32_t numSamples) override;
 
 private:
@@ -40,6 +44,7 @@ private:
     // 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];
+    uint32_t program_[16];
 };
 
 // sfizz (.sfz)
@@ -97,6 +102,14 @@ public:
     // case-insensitive — caller must lowercase before comparing.
     std::string pathOf(uint32_t channel);
 
+    // G2.1: copy every assigned channel into a state snapshot (channel,
+    // type, path, VST3 preset blob -> base64, SF2/SF3 bank/program).
+    // MUST run on the channel worker (captureState enters the plugin);
+    // takes mu_ for the whole call so the audio loop cannot be inside
+    // process() on the same instance while its state is captured.
+    // Channels mid-reload are skipped (their old instance is dying).
+    bool snapshot(BridgeStateSnapshot& out);
+
     // 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.
@@ -128,6 +141,7 @@ private:
     mutable std::mutex mu_;
     std::map<uint32_t, std::unique_ptr<INativeInstrument>> channels_;
     std::map<uint32_t, std::string> paths_;  // last assigned path per channel
+    std::map<uint32_t, InstrumentType> types_;  // last assigned type per channel (G2.1)
     // Per-instrument scratch so engines that overwrite (not mix) stay additive.
     std::vector<float> scratchL_, scratchR_;
     // Channel-level reload flag (see isReloading) — indexed by MIDI channel.