#include <napi.h>
#include "d3d_device.h"
#include "capture.h"
#include "common.h"

// Forward-declare the DwmGetDxSharedSurface lookup (defined in capture.cpp).
// We re-check here so isAvailable() reflects true availability.
static bool CheckDwmSharedSurfaceAvailable() {
    HMODULE hUser32 = GetModuleHandleW(L"user32.dll");
    if (!hUser32) return false;
    return GetProcAddress(hUser32, "DwmGetDxSharedSurface") != nullptr;
}

// Check if DWM shared surface capture is available on this platform.
// Requires: D3D11 device + DwmGetDxSharedSurface in user32.dll.
Napi::Value IsAvailable(const Napi::CallbackInfo& info) {
    bool available = IsD3DAvailable() && CheckDwmSharedSurfaceAvailable();
    return Napi::Boolean::New(info.Env(), available);
}

// captureWindow(hwnd: number) -> Promise<Buffer>
// Dispatches CaptureWorker to perform DWM shared surface capture on a libuv worker thread.
Napi::Value CaptureWindow(const Napi::CallbackInfo& info) {
    Napi::Env env = info.Env();

    // Validate argument: expects one Number (the HWND)
    if (info.Length() < 1 || !info[0].IsNumber()) {
        auto deferred = Napi::Promise::Deferred::New(env);
        deferred.Reject(Napi::String::New(env, "captureWindow expects a numeric HWND argument"));
        return deferred.Promise();
    }

    // Check D3D11 availability
    if (!IsD3DAvailable()) {
        auto deferred = Napi::Promise::Deferred::New(env);
        deferred.Reject(Napi::String::New(env, "D3D11 not available"));
        return deferred.Promise();
    }

    // Extract HWND from JavaScript number
    HWND hwnd = reinterpret_cast<HWND>(static_cast<intptr_t>(info[0].As<Napi::Number>().Int64Value()));

    // Create and queue async worker
    auto* worker = new CaptureWorker(env, hwnd, GetD3DDevice(), GetD3DContext());
    auto promise = worker->GetPromise();
    worker->Queue();
    return promise;
}

// Return current GDI object count for this process (for leak testing).
Napi::Value GetGdiHandleCount(const Napi::CallbackInfo& info) {
    DWORD count = GetGuiResources(GetCurrentProcess(), GR_GDIOBJECTS);
    return Napi::Number::New(info.Env(), static_cast<double>(count));
}

Napi::Object Init(Napi::Env env, Napi::Object exports) {
    // Initialize D3D11 device singleton at addon load (per D-17)
    InitializeD3D();
    DWM_LOG("Addon loaded, D3D11 available: %s, DwmGetDxSharedSurface: %s",
            IsD3DAvailable() ? "yes" : "no",
            CheckDwmSharedSurfaceAvailable() ? "yes" : "no");

    exports.Set("isAvailable", Napi::Function::New(env, IsAvailable));
    exports.Set("captureWindow", Napi::Function::New(env, CaptureWindow));
    exports.Set("getGdiHandleCount", Napi::Function::New(env, GetGdiHandleCount));
    return exports;
}

NODE_API_MODULE(dwm_capture, Init)