// fake_vst2.cpp — test plugin VST2 tối thiểu để verify bridge T10.
// Sine 440Hz stereo qua processReplacing; editor trả rect giả.
#define NOMINMAX
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <cmath>
#include <cstring>
#include "vestige.h"

namespace {

struct FakeState
{
    float phase = 0.0f;
    int32 sampleRate = 44100;
    float gain = 0.5f; // param 0 — "Gain" (0..1)
};

FakeState g_state;
void* g_audioMaster = nullptr;

void VSTCALLBACK fakeSetParameter (AEffect* effect, int32 index, float value)
{
    if (index == 0)
    {
        g_state.gain = value;
        // Báo host: param đổi từ editor/plugin (T11) — chống loop host-side.
        if (g_audioMaster)
        {
            typedef VstIntPtr (VSTCALLBACK* AMFn) (AEffect*, int32, int32, VstIntPtr, void*, float);
            reinterpret_cast<AMFn> (g_audioMaster) (effect, audioMasterAutomate, index, 0, nullptr,
                                                    value);
        }
    }
}

float VSTCALLBACK fakeGetParameter (AEffect*, int32 index)
{
    if (index == 0)
        return g_state.gain;
    return 0.0f;
}

int32 VSTCALLBACK fakeDispatcher (AEffect* effect, int32 opcode, int32 index,
                                  VstIntPtr value, void* ptr, float opt)
{
    (void) index;
    (void) value;
    (void) ptr;
    (void) opt;
    switch (opcode)
    {
        case effOpen:
            return 1;
        case effClose:
            return 1;
        case effSetSampleRate:
            g_state.sampleRate = static_cast<int32> (opt);
            return 1;
        case effMainsChanged:
            return 1;
        case effStartProcess:
        case effStopProcess:
            return 1;
        case effEditGetRect:
        {
            static ERect rect = {0, 0, 300, 400};
            *reinterpret_cast<ERect**> (ptr) = &rect;
            return 1;
        }
        case effEditOpen:
            return 1;
        case effEditClose:
            return 1;
        case effProcessEvents:
            return 1;
        case effGetEffectName:
            std::strncpy (static_cast<char*> (ptr), "FakeVST2", 64);
            return 1;
        case effGetVendorString:
            std::strncpy (static_cast<char*> (ptr), "SonicForgeStudio", 64);
            return 1;
        case effGetProductString:
            std::strncpy (static_cast<char*> (ptr), "FakeVST2", 64);
            return 1;
        case effGetVendorVersion:
            return 1;
        case effIdentify:
            return CCONST ('N', 'v', 'E', 'f');
        case effCanDo:
            return 0;
        default:
            return 0;
    }
}

void VSTCALLBACK fakeProcessReplacing (AEffect*, float** inputs, float** outputs,
                                       int32 sampleFrames)
{
    (void) inputs;
    float* outL = outputs[0];
    float* outR = outputs[1];
    const float freq = 440.0f;
    const float dt = freq / static_cast<float> (g_state.sampleRate);
    for (int32 i = 0; i < sampleFrames; ++i)
    {
        float v = 0.25f * std::sin (2.0f * 3.14159265f * g_state.phase);
        g_state.phase += dt;
        if (g_state.phase >= 1.0f)
            g_state.phase -= 1.0f;
        outL[i] = v;
        outR[i] = v;
    }
}

AEffect g_effect;

AEffect* VSTCALLBACK createInstance (void* audioMaster)
{
    g_audioMaster = audioMaster;
    std::memset (&g_effect, 0, sizeof (g_effect));
    g_effect.magic = CCONST ('V', 's', 't', 'P');
    g_effect.dispatcher = &fakeDispatcher;
    g_effect.processReplacing = &fakeProcessReplacing;
    g_effect.setParameter = &fakeSetParameter;
    g_effect.getParameter = &fakeGetParameter;
    g_effect.numInputs = [] (AEffect*) -> int32 { return 0; };
    g_effect.numOutputs = [] (AEffect*) -> int32 { return 2; };
    g_effect.numParams = [] (AEffect*) -> int32 { return 1; };
    g_effect.numPrograms = [] (AEffect*) -> int32 { return 0; };
    g_effect.flags = [] (AEffect*) -> int32 { return effFlagsCanReplacing | effFlagsIsSynth; };
    g_effect.uniqueID = CCONST ('F', 'k', '2', 'V');
    g_effect.version = 1;
    return &g_effect;
}

} // namespace

extern "C" __declspec (dllexport) AEffect* VSTPluginMain (void* audioMaster)
{
    return createInstance (audioMaster);
}