// native_bridge/vestige/aeffect.h
// Clean-room VST2.4 host ABI header (64-bit Windows).
//
// Written from the public VST2.4 interface specification (structure layout,
// dispatcher opcode numbers, flag bits) — NOT copied from Steinberg's SDK or
// from LMMS's vestige (LMMS is GPL-2.0+; reusing it would re-taint the bridge
// with GPL, defeating this repo's license cleanup). Only ABI facts are
// encoded here; all prose is original.
//
// A VST2 plugin is a DLL exporting `VSTPluginMain` (modern) or `main`
// (legacy):  AEffect* VSTPluginMain(audioMasterCallback host).
#ifndef VESTIGE_AEFFECT_H
#define VESTIGE_AEFFECT_H

#include <cstdint>

struct AEffect;  // forward decl so the callback typedefs below can reference it

// intptr_t: VST2 ABI uses pointer-sized integers on 64-bit hosts.
typedef intptr_t (*dispatcherProc)(AEffect* effect, int32_t opcode,
                                   int32_t index, intptr_t value,
                                   void* ptr, float opt);
typedef void (*processProc)(AEffect* effect, float** inputs, float** outputs,
                            int32_t sampleFrames);
typedef void (*setParameterProc)(AEffect* effect, int32_t index, float value);
typedef float (*getParameterProc)(AEffect* effect, int32_t index);
typedef void (*processReplacingProc)(AEffect* effect, float** inputs,
                                     float** outputs, int32_t sampleFrames);
typedef void (*processDoubleReplacingProc)(AEffect* effect, double** inputs,
                                           double** outputs,
                                           int32_t sampleFrames);
typedef intptr_t (*audioMasterCallback)(AEffect* effect, int32_t opcode,
                                        int32_t index, intptr_t value,
                                        void* ptr, float opt);

struct AEffect {
    int32_t magic;               // 'VstP' == 0x56737450
    dispatcherProc dispatcher;
    processProc process;
    setParameterProc setParameter;
    getParameterProc getParameter;
    int32_t numPrograms;
    int32_t numParams;
    int32_t numInputs;
    int32_t numOutputs;
    int32_t flags;
    intptr_t resvd1;             // pointer-sized per VST2.4 ABI
    intptr_t resvd2;
    int32_t initialDelay;
    int32_t realQualities;
    int32_t offQualities;
    float ioRatio;
    void* object;
    void* user;
    int32_t uniqueID;
    int32_t version;
    processReplacingProc processReplacing;
    processDoubleReplacingProc processDoubleReplacing;
    char future[56];             // reserved for future use (must stay intact)
};

// Plugin capability flag bits (AEffect::flags).
#define kEffectFlagsHasEditor             (1 << 0)
#define kEffectFlagsHasClip               (1 << 1)
#define kEffectFlagsHasVu                 (1 << 2)
#define kEffectFlagsCanMono               (1 << 3)
#define kEffectFlagsCanReplacing          (1 << 4)
#define kEffectFlagsProgramChunks         (1 << 5)
#define kEffectFlagsIsSynth               (1 << 8)
#define kEffectFlagsNoSoundInStop         (1 << 9)
#define kEffectFlagsCanDoubleReplacing    (1 << 12)

// Dispatcher opcodes (VST 2.4 numbering).
enum {
    kEffectOpen = 0,             // effOpen
    kEffectClose = 1,            // effClose
    kEffectSetProgram = 2,       // effSetProgram
    kEffectGetProgram = 3,       // effGetProgram
    kEffectSetProgramName = 4,   // effSetProgramName (ptr = char* name)
    kEffectGetProgramName = 5,   // effGetProgramName (ptr = char* buffer)
    kEffectGetParamLabel = 6,    // effGetParamLabel (ptr = char* buffer)
    kEffectGetParamDisplay = 7,  // effGetParamDisplay (ptr = char* buffer)
    kEffectGetParamName = 8,     // effGetParamName (ptr = char* buffer)
    kEffectGetVu = 9,            // effGetVu (deprecated; occupies the slot so
                                 // the core opcodes below match the SDK)
    kEffectSetSampleRate = 10,   // effSetSampleRate (opt = sample rate)
    kEffectSetBlockSize = 11,    // effSetBlockSize (value = block size)
    kEffectMainsChanged = 12,    // effMainsChanged (value 1 = on, 0 = off)
    kEffectEditGetRect = 13,     // effEditGetRect (ptr = ERect**)
    kEffectEditOpen = 14,        // effEditOpen (ptr = host window HWND)
    kEffectEditClose = 15,       // effEditClose
    kEffectEditDraw = 16,        // effEditDraw (deprecated)
    kEffectEditMouse = 17,       // effEditMouse (deprecated)
    kEffectEditKey = 18,         // effEditKey (deprecated)
    kEffectEditIdle = 19,        // effEditIdle
    kEffectEditTop = 20,         // effEditTop (deprecated)
    kEffectEditSleep = 21,       // effEditSleep (deprecated)
    kEffectIdentify = 22,        // effIdentify (deprecated)
    kEffectGetChunk = 23,        // effGetChunk
    kEffectSetChunk = 24,        // effSetChunk
    kEffectProcessEvents = 25,   // effProcessEvents
    kEffectGetPlugCategory = 35,
    kEffectGetEffectName = 45,
    kEffectGetVendorString = 47,
    kEffectGetProductString = 48,
    kEffectGetVendorVersion = 49,
    kEffectCanDo = 51,
    kEffectIdle = 53,            // effIdle
    kEffectSetViewPosition = 55, // effSetViewPosition
    kEffectGetVstVersion = 58,
    kEffectStartProcess = 71,
    kEffectStopProcess = 72
};

// audioMaster opcodes (host callback).
enum {
    kAudioMasterAutomate = 0,
    kAudioMasterVersion = 1,
    kAudioMasterCurrentId = 2,
    kAudioMasterIdle = 3,
    kAudioMasterWantMidi = 6,
    kAudioMasterGetTime = 7,
    kAudioMasterProcessEvents = 8,
    kAudioMasterGetSampleRate = 16,
    kAudioMasterGetBlockSize = 17,
    kAudioMasterGetCurrentProcessLevel = 23,
    kAudioMasterGetVendorString = 32,
    kAudioMasterGetProductString = 33,
    kAudioMasterGetVendorVersion = 34,
    kAudioMasterVendorSpecific = 35,
    kAudioMasterCanDo = 37,
    kAudioMasterGetLanguage = 38,
    kAudioMasterSizeWindow = 15,    // index = width, value = height
    kAudioMasterGetDirectory = 41,  // ptr = char* (VST dir); 0 = none
    kAudioMasterUpdateDisplay = 42, // request host display refresh
    kAudioMasterBeginEdit = 43,     // parameter automation begin
    kAudioMasterEndEdit = 44        // parameter automation end
};

// Editor rectangle returned by effEditGetRect (short coords per VST2 ABI).
struct ERect {
    short top;
    short left;
    short bottom;
    short right;
};

// MIDI event passed via effProcessEvents. The plugin receives a VstEvents
// array; each event starts with a VstEvent header, VstMidiEvent extends it.
struct VstEvent {
    int32_t type;       // kVstMidiType == 1 for MIDI events
    int32_t byteSize;   // sizeof(VstMidiEvent)
    int32_t deltaFrames;
    int32_t flags;
};

struct VstMidiEvent {
    int32_t type;       // kVstMidiType == 1
    int32_t byteSize;   // sizeof(VstMidiEvent)
    int32_t deltaFrames;
    int32_t flags;
    int32_t noteLength; // in sample frames, if available, else 0
    int32_t noteOffset; // offset into note, if available, else 0
    char midiData[4];   // 1-3 MIDI bytes; midiData[3] reserved (zero)
    char detune;        // -64..+63 cents
    char noteOffVelocity;
    char reserved1;
    char reserved2;
};

struct VstEvents {
    int32_t numEvents;
    intptr_t reserved;
    VstEvent* events[2];
};

// Time info returned to kAudioMasterGetTime (host fills this).
struct VstTimeInfo {
    double samplePos;
    double sampleRate;
    double nanoSeconds;
    double ppqPos;
    double tempo;
    double barStartPos;
    double cycleStartPos;
    double cycleEndPos;
    int32_t timeSigNumerator;
    int32_t timeSigDenominator;
    int32_t smpteOffset;
    int32_t smpteFrameRate;
    int32_t samplesToNextClock;
    int32_t flags;
};

#define kVstMidiType 1
#define kVstMidiEventIsRealtime 1  // VstMidiEvent::flags: live input (not sequencer playback)
#define kEffectMagic 0x56737450  // 'VstP'

// VstTimeInfo::flags bits (kAudioMasterGetTime).
#define kVstTransportPlaying  1
#define kVstTransportCycleActive 2
#define kVstTransportChanged  4
#define kVstTempoValid        8

// Host responses for the plugin's capability probes (kEffectCanDo).
#define kCanDoYes 1
#define kCanDoNo 0

#endif // VESTIGE_AEFFECT_H