#include "alfpriv.h"

#include <shlwapi.h>

#if defined(_MSC_VER) && defined(_M_IX86)

#   pragma warning(push)
#   pragma warning(disable:4035)

    // HACK: inline assembly for MSVC 6
    // TODO: add version detection to use intrinsic on newer MSVC versions

    static inline LONG
    ALF_Compat_InterlockedIncrement(LONG volatile *addend)
    {
        __asm {
            mov         eax,1
            mov         edx,addend
            lock xadd   [edx],eax
        }
    }
#   ifdef InterlockedIncrement
#       undef InterlockedIncrement
#   endif
#   define InterlockedIncrement(d) ALF_Compat_InterlockedIncrement(d)

    static inline LONG
    ALF_Compat_InterlockedCompareExchange(volatile LONG *destination, LONG exchange, LONG comparand)
    {
        __asm {
            mov             eax,comparand
            mov             ecx,exchange
            mov             edx,destination
            lock cmpxchg    [edx],ecx
        }
    }

#   ifdef InterlockedCompareExchange
#       undef InterlockedCompareExchange
#   endif
#   define InterlockedCompareExchange(d,e,c) ALF_Compat_InterlockedCompareExchange(d,e,c)

    static inline PVOID
    ALF_Compat_InterlockedCompareExchangePointer(PVOID volatile *destination, PVOID exchange, PVOID comparand)
    {
        return (void*)InterlockedCompareExchange((LONG volatile *)destination, (LONG)exchange, (LONG)comparand);
    }

#   ifdef InterlockedCompareExchangePointer
#       undef InterlockedCompareExchangePointer
#   endif
#   define InterlockedCompareExchangePointer(d,e,c) ALF_Compat_InterlockedCompareExchangePointer(d,e,c)

#   pragma warning(pop)
#endif

static
DWORD ALF_DllGetVersion(const char *dll)
{
    HMODULE hDll = GetModuleHandleA(dll);

    if (hDll) {
        DLLGETVERSIONPROC pDllGetVersion;
        pDllGetVersion = (DLLGETVERSIONPROC)(void*)GetProcAddress(hDll, "DllGetVersion");

        if (pDllGetVersion) {
            DLLVERSIONINFO dvi;
            HRESULT hr;

            ZeroMemory(&dvi, sizeof(dvi));
            dvi.cbSize = sizeof(dvi);

            hr = (*pDllGetVersion)(&dvi);

            if (SUCCEEDED(hr)) {
                return MAKELONG(dvi.dwMinorVersion, dvi.dwMajorVersion);
            }
        }
    }
    return 0;
}

static int WINAPI
ALF_Compat_fallbackGetSystemMetricsForDpi(int nIndex, UINT dpi)
{
    (void)dpi;
    if (LOBYTE(LOWORD(GetVersion())) < 4) {
        // old NT does not support several properties, so we fake them
        switch (nIndex) {
            case SM_CXEDGE:
            case SM_CYEDGE:
                return 2;
        }
    }
    return GetSystemMetrics(nIndex);
}

static BOOL WINAPI
ALF_Compat_fallbackIsAppThemed(void)
{
    return FALSE;
}

static UINT WINAPI
ALF_Compat_fallbackGetDpiForWindow(HWND win)
{
    (void)win;

    UINT dpi = 0;

    HDC hdcScreen = GetDC(NULL);
    if (hdcScreen) {
        dpi = GetDeviceCaps(hdcScreen, LOGPIXELSY);
        ReleaseDC(NULL, hdcScreen);
    }

    if (!dpi) {
        dpi = 96; // FIXME! fallback to default DPI
    }

    return dpi;
}

static BOOL WINAPI
ALF_Compat_fallbackSystemParametersInfoForDpi(UINT uiAction, UINT uiParam, PVOID pvParam, UINT fWinIni, UINT dpi)
{
    (void)dpi;

    return SystemParametersInfo(uiAction, uiParam, pvParam, fWinIni);
}

static BOOL WINAPI
ALF_Compat_fallbackAdjustWindowRectExForDpi(LPRECT lpRect, DWORD dwStyle, BOOL bMenu, DWORD dwExStyle, UINT dpi)
{
    (void)dpi;

    return AdjustWindowRectEx(lpRect, dwStyle, bMenu, dwExStyle);
}


// FIXME: these support one subclass only, negating the whole point of it

typedef struct {
    ALF_COMPAT_SUBCLASSPROC pfnSubclass;
    UINT_PTR uIdSubclass;
    DWORD_PTR dwRefData;
    UINT runCounter;
    WNDPROC orig;
} ALFWindowSubclassData;

static LRESULT CALLBACK
ALF_Compat_fallbackSubclassProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    ALFWindowSubclassData *data = (ALFWindowSubclassData *)GetWindowLongPtr(hwnd, GWLP_USERDATA);

    LRESULT ret = 0;

    data->runCounter++;

    if (data->pfnSubclass)
        ret = data->pfnSubclass(hwnd, uMsg, wParam, lParam, data->uIdSubclass, data->dwRefData);
    else
        ret = CallWindowProc(data->orig, hwnd, uMsg, wParam, lParam);

    data->runCounter--;

    if (!data->pfnSubclass && !data->runCounter) {
        SetWindowLongPtr(hwnd, GWLP_USERDATA, 0);
        ALF_Free(data);
    }

    return ret;
}

static BOOL WINAPI
ALF_Compat_fallbackSetWindowSubclass(HWND hwnd, ALF_COMPAT_SUBCLASSPROC pfnSubclass, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)
{
    ALFWindowSubclassData *data = ALF_New(ALFWindowSubclassData, 1);

    data->pfnSubclass = pfnSubclass;
    data->uIdSubclass = uIdSubclass;
    data->dwRefData = dwRefData;
    data->orig = (WNDPROC)GetWindowLongPtr(hwnd, GWLP_WNDPROC);

    SetWindowLongPtr(hwnd, GWLP_USERDATA, (LONG_PTR)data);
    SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR)ALF_Compat_fallbackSubclassProc);

    return TRUE;
}

static LRESULT WINAPI
ALF_Compat_fallbackDefSubclassProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    ALFWindowSubclassData *data = (ALFWindowSubclassData *)GetWindowLongPtr(hwnd, GWLP_USERDATA);

    return CallWindowProc(data->orig, hwnd, uMsg, wParam, lParam);
}

static BOOL WINAPI
ALF_Compat_fallbackRemoveWindowSubclass(HWND hwnd, ALF_COMPAT_SUBCLASSPROC pfnSubclass, UINT_PTR uIdSubclass)
{
    (void)pfnSubclass;
    (void)uIdSubclass;

    ALFWindowSubclassData *data = (ALFWindowSubclassData *)GetWindowLongPtr(hwnd, GWLP_USERDATA);

    data->pfnSubclass = 0;
    data->uIdSubclass = 0;
    SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR)data->orig);

    // can't free it while the subclass is running, possibly in a nested SendMessage
    // and wants to call DefSubclassProc
    if (!data->runCounter) {
        SetWindowLongPtr(hwnd, GWLP_USERDATA, 0);
        ALF_Free(data);
    }

    return TRUE;
}

long
ALF_GetAveCharWidth(HDC hdc)
{
    // see: HOWTO: Calculate Dialog Units When Not Using the System Font

    SIZE s;
    GetTextExtentPoint32A(hdc, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz", 52, &s);

    return (s.cx / 26 + 1) / 2;
}

void
ALF_UniqueCounterValue(LONG_PTR *pCounterId, LONG_PTR *pCounterValue)
{
    static LONG counter = 0;

    LONG r = InterlockedIncrement(&counter);
    *pCounterId    = (LONG_PTR)&counter;
    *pCounterValue = r;
}

static BOOL WINAPI
ALF_Compat_loadIsAppThemed(void)
{
    HMODULE hUxTheme = GetModuleHandleA("uxtheme.dll");
    FARPROC p = GetProcAddress(hUxTheme, "IsAppThemed");

    if (!p || ALF_DllGetVersion("comctl32.dll") < 0x60000)
        p = (FARPROC)ALF_Compat_fallbackIsAppThemed;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_IsAppThemed, (void*)p, (void*)ALF_Compat_loadIsAppThemed);

    return ALF_Compat_IsAppThemed();
}

static UINT WINAPI
ALF_Compat_loadGetDpiForWindow(HWND window)
{
    FARPROC p = GetProcAddress(GetModuleHandleA("user32.dll"), "GetDpiForWindow");

    if (!p)
        p = (FARPROC)(void*)ALF_Compat_fallbackGetDpiForWindow;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_GetDpiForWindow, (void*)p, (void*)ALF_Compat_loadGetDpiForWindow);

    return ALF_Compat_GetDpiForWindow(window);
}

static BOOL WINAPI
ALF_Compat_loadAdjustWindowRectExForDpi(LPRECT lpRect, DWORD dwStyle, BOOL bMenu, DWORD dwExStyle, UINT dpi)
{
    FARPROC p = GetProcAddress(GetModuleHandleA("user32.dll"), "AdjustWindowRectExForDpi");

    if (!p)
        p = (FARPROC)(void*)ALF_Compat_fallbackAdjustWindowRectExForDpi;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_AdjustWindowRectExForDpi, (void*)p, (void*)ALF_Compat_loadAdjustWindowRectExForDpi);

    return ALF_Compat_AdjustWindowRectExForDpi(lpRect, dwStyle, bMenu, dwExStyle, dpi);
}

static int WINAPI
ALF_Compat_loadGetSystemMetricsForDpi(int nIndex, UINT dpi)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("user32.dll"), "GetSystemMetricsForDpi");

    if (!p)
        p = (void*)ALF_Compat_fallbackGetSystemMetricsForDpi;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_GetSystemMetricsForDpi, p, (void*)ALF_Compat_loadGetSystemMetricsForDpi);

    return ALF_Compat_GetSystemMetricsForDpi(nIndex, dpi);
}

static BOOL WINAPI
ALF_Compat_loadSetWindowSubclass(HWND hwnd, ALF_COMPAT_SUBCLASSPROC pfnSubclass, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)
{
    HMODULE comctl32 = GetModuleHandleA("comctl32.dll");

    void *p = (void*)GetProcAddress(comctl32, "SetWindowSubclass");
    if (!p) {
        p = (void*)GetProcAddress(comctl32, (char*)410);
        if (!p) {
            p = (void*)ALF_Compat_fallbackSetWindowSubclass;
        }
    }

    InterlockedCompareExchangePointer((void**)&ALF_Compat_SetWindowSubclass, p, (void*)ALF_Compat_loadSetWindowSubclass);

    return ALF_Compat_SetWindowSubclass(hwnd, pfnSubclass, uIdSubclass, dwRefData);
}

static BOOL WINAPI
ALF_Compat_loadRemoveWindowSubclass(HWND hwnd, ALF_COMPAT_SUBCLASSPROC pfnSubclass, UINT_PTR uIdSubclass)
{
    HMODULE comctl32 = GetModuleHandleA("comctl32.dll");

    void *p = (void*)GetProcAddress(comctl32, "RemoveWindowSubclass");
    if (!p) {
        p = (void*)GetProcAddress(comctl32, (char*)412);
        if (!p) {
            p = (void*)ALF_Compat_fallbackRemoveWindowSubclass;
        }
    }

    InterlockedCompareExchangePointer((void**)&ALF_Compat_RemoveWindowSubclass, p, (void*)ALF_Compat_loadRemoveWindowSubclass);

    return ALF_Compat_RemoveWindowSubclass(hwnd, pfnSubclass, uIdSubclass);
}

static LRESULT WINAPI
ALF_Compat_loadDefSubclassProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    HMODULE comctl32 = GetModuleHandleA("comctl32.dll");

    void *p = (void*)GetProcAddress(comctl32, "DefSubclassProc");
    if (!p) {
        p = (void*)GetProcAddress(comctl32, (char*)413);
        if (!p) {
            p = (void*)ALF_Compat_fallbackDefSubclassProc;
        }
    }

    InterlockedCompareExchangePointer((void**)&ALF_Compat_DefSubclassProc, p, (void*)ALF_Compat_loadDefSubclassProc);

    return ALF_Compat_DefSubclassProc(hwnd, uMsg, wParam, lParam);
}

static BOOL WINAPI
ALF_Compat_loadSystemParametersInfoForDpi(UINT uiAction, UINT uiParam, PVOID pvParam, UINT fWinIni, UINT dpi)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("user32.dll"), "SystemParametersInfoForDpi");
    if (!p)
        p = (void*)ALF_Compat_fallbackSystemParametersInfoForDpi;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_SystemParametersInfoForDpi, p, (void*)ALF_Compat_loadSystemParametersInfoForDpi);

    return ALF_Compat_SystemParametersInfoForDpi(uiAction, uiParam, pvParam, fWinIni, dpi);
}

static HTHEME WINAPI
ALF_Compat_fallbackOpenThemeData(HWND window, LPCWSTR classNames)
{
    (void)window;
    (void)classNames;

    return NULL;
}

static HTHEME WINAPI
ALF_Compat_loadOpenThemeData(HWND window, LPCWSTR classNames)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "OpenThemeData");
    if (!p)
        p = (void*)ALF_Compat_fallbackOpenThemeData;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_OpenThemeData, p, (void*)ALF_Compat_loadOpenThemeData);

    return ALF_Compat_OpenThemeData(window, classNames);
}

static HRESULT WINAPI
ALF_Compat_fallbackCloseThemeData(HTHEME hTheme)
{
    (void)hTheme;

    return S_OK;
}

static HRESULT WINAPI
ALF_Compat_loadCloseThemeData(HTHEME hTheme)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "CloseThemeData");
    if (!p)
        p = (void*)ALF_Compat_fallbackCloseThemeData;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_CloseThemeData, p, (void*)ALF_Compat_loadCloseThemeData);

    return ALF_Compat_CloseThemeData(hTheme);
}

static BOOL WINAPI
ALF_Compat_fallbackIsThemeBackgroundPartiallyTransparent(HTHEME hTheme, int iPartId, int iStateId)
{
    (void)hTheme; (void)iPartId; (void)iStateId;

    return TRUE;
}

static BOOL WINAPI
ALF_Compat_loadIsThemeBackgroundPartiallyTransparent(HTHEME hTheme, int iPartId, int iStateId)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "IsThemeBackgroundPartiallyTransparent");
    if (!p)
        p = (void*)ALF_Compat_fallbackIsThemeBackgroundPartiallyTransparent;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_IsThemeBackgroundPartiallyTransparent, p, (void*)ALF_Compat_loadIsThemeBackgroundPartiallyTransparent);

    return ALF_Compat_IsThemeBackgroundPartiallyTransparent(hTheme, iPartId, iStateId);
}

static HRESULT WINAPI
ALF_Compat_fallbackDrawThemeParentBackground(HWND hwnd, HDC hdc, RECT *prc)
{
    (void)hwnd;
    (void)hdc;
    (void)prc;

    return E_NOTIMPL;
}

static HRESULT WINAPI
ALF_Compat_loadDrawThemeParentBackground(HWND hwnd, HDC hdc, RECT *prc)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "DrawThemeParentBackground");
    if (!p)
        p = (void*)ALF_Compat_fallbackDrawThemeParentBackground;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_DrawThemeParentBackground, p, (void*)ALF_Compat_loadDrawThemeParentBackground);

    return ALF_Compat_DrawThemeParentBackground(hwnd, hdc, prc);
}

static HRESULT WINAPI
ALF_Compat_fallbackDrawThemeBackground(HTHEME hTheme, HDC hdc, int iPartId, int iStateId, const RECT *pRect, const RECT *pClipRect)
{
    (void)hTheme;
    (void)hdc;
    (void)iPartId;
    (void)iStateId;
    (void)pRect;
    (void)pClipRect;

    return E_NOTIMPL;
}

static HRESULT WINAPI
ALF_Compat_loadDrawThemeBackground(HTHEME hTheme, HDC hdc, int iPartId, int iStateId, const RECT *pRect, const RECT *pClipRect)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "DrawThemeBackground");
    if (!p)
        p = (void*)ALF_Compat_fallbackDrawThemeBackground;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_DrawThemeBackground, p, (void*)ALF_Compat_loadDrawThemeBackground);

    return ALF_Compat_DrawThemeBackground(hTheme, hdc, iPartId, iStateId, pRect, pClipRect);
}

static HRESULT WINAPI
ALF_Compat_fallbackGetThemeBackgroundContentRect(HTHEME hTheme, HDC hdc, int iPartId, int iStateId, const RECT *pBoundingRect, RECT *pContentRect)
{
    (void)hTheme;
    (void)hdc;
    (void)iPartId;
    (void)iStateId;
    (void)pBoundingRect;
    (void)pContentRect;

    return E_NOTIMPL;
}

static HRESULT WINAPI
ALF_Compat_loadGetThemeBackgroundContentRect(HTHEME hTheme, HDC hdc, int iPArtId, int iStateId, const RECT *pBoundingRect, RECT *pContentRect)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "GetThemeBackgroundContentRect");
    if (!p)
        p = (void*)ALF_Compat_fallbackGetThemeBackgroundContentRect;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_GetThemeBackgroundContentRect, p, (void*)ALF_Compat_loadGetThemeBackgroundContentRect);

    return ALF_Compat_GetThemeBackgroundContentRect(hTheme, hdc, iPArtId, iStateId, pBoundingRect, pContentRect);
}

static HRESULT WINAPI
ALF_Compat_fallbackGetThemeTextExtent(HTHEME hTheme, HDC hdc, int iPartId,
                                      int iStateId, LPCWSTR pszText, int iCharCount,
                                      DWORD dwTextFlags, const RECT *pBoundingRect,
                                      RECT *pExtentRect)
{
    (void)hTheme; (void)hdc; (void)iPartId; (void)iStateId; (void)pszText;
    (void)iCharCount; (void)dwTextFlags; (void)pBoundingRect; (void)pExtentRect;

    return E_NOTIMPL;
}

static HRESULT WINAPI
ALF_Compat_loadGetThemeTextExtent(HTHEME hTheme, HDC hdc, int iPartId,
                                  int iStateId, LPCWSTR pszText, int iCharCount,
                                  DWORD dwTextFlags, const RECT *pBoundingRect,
                                  RECT *pExtentRect)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "GetThemeTextExtent");
    if (!p)
        p = (void*)ALF_Compat_fallbackGetThemeTextExtent;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_GetThemeTextExtent, p, (void*)ALF_Compat_loadGetThemeTextExtent);

    return ALF_Compat_GetThemeTextExtent(hTheme, hdc, iPartId, iStateId, pszText, iCharCount, dwTextFlags, pBoundingRect, pExtentRect);
}

static HRESULT WINAPI
ALF_Compat_fallbackDrawThemeText(HTHEME hTheme, HDC hdc, int iPartId, int iStateId,
                                 LPCWSTR pszText, int iCharCount, DWORD dwTextFlags,
                                 DWORD dwTextFlags2, const RECT *pRect)
{
    (void)hTheme; (void)hdc; (void)iPartId; (void)iStateId; (void)pszText;
    (void)iCharCount; (void)dwTextFlags; (void)dwTextFlags2; (void)pRect;

    return E_NOTIMPL;
}

static HRESULT WINAPI
ALF_Compat_loadDrawThemeText(HTHEME hTheme, HDC hdc, int iPartId, int iStateId,
                             LPCWSTR pszText, int iCharCount, DWORD dwTextFlags,
                             DWORD dwTextFlags2, const RECT *pRect)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "DrawThemeText");
    if (!p)
        p = (void*)ALF_Compat_fallbackDrawThemeText;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_DrawThemeText, p, (void*)ALF_Compat_loadDrawThemeText);

    return ALF_Compat_DrawThemeText(hTheme, hdc, iPartId, iStateId, pszText, iCharCount, dwTextFlags, dwTextFlags2, pRect);
}

static BOOL WINAPI
ALF_Compat_fallbackTrackMouseEvent(LPTRACKMOUSEEVENT tme)
{
    (void)tme;

    return FALSE;
}

static BOOL WINAPI
ALF_Compat_loadTrackMouseEvent(LPTRACKMOUSEEVENT tme)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("comctl32.dll"), "_TrackMouseEvent");
    if (!p)
        p = (void*)ALF_Compat_fallbackTrackMouseEvent;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_TrackMouseEvent, p, (void*)ALF_Compat_loadTrackMouseEvent);

    return ALF_Compat_TrackMouseEvent(tme);
}

static HRESULT WINAPI
ALF_Compat_fallbackBufferedPaintInit(void)
{
    return E_NOTIMPL;
}

static HRESULT WINAPI
ALF_Compat_loadBufferedPaintInit(void)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "BufferedPaintInit");
    if (!p)
        p = (void*)ALF_Compat_fallbackBufferedPaintInit;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_BufferedPaintInit, p, (void*)ALF_Compat_loadBufferedPaintInit);

    return ALF_Compat_BufferedPaintInit();
}

static HRESULT WINAPI
ALF_Compat_fallbackBufferedPaintUnInit(void)
{
    return E_NOTIMPL;
}

static HRESULT WINAPI
ALF_Compat_loadBufferedPaintUnInit(void)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "BufferedPaintUnInit");
    if (!p)
        p = (void*)ALF_Compat_fallbackBufferedPaintUnInit;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_BufferedPaintUnInit, p, (void*)ALF_Compat_loadBufferedPaintUnInit);

    return ALF_Compat_BufferedPaintUnInit();
}

static ALF_Compat_HANIMATIONBUFFER WINAPI
ALF_Compat_fallbackBeginBufferedAnimation(HWND hwnd, HDC hdcTarget,
                                          const RECT *prcTarget, DWORD dwFormat,
                                          ALF_Compat_BP_PAINTPARAMS *pPaintParams,
                                          ALF_Compat_BP_ANIMATIONPARAMS *pAnimationParams,
                                          HDC *phdcFrom, HDC *phdcTo)
{
    (void)hwnd; (void)hdcTarget; (void)prcTarget; (void)dwFormat;
    (void)pPaintParams; (void)pAnimationParams; (void)phdcFrom; (void)phdcTo;

    return NULL;
}

static ALF_Compat_HANIMATIONBUFFER WINAPI
ALF_Compat_loadBeginBufferedAnimation(HWND hwnd, HDC hdcTarget,
                                      const RECT *prcTarget, DWORD dwFormat,
                                      ALF_Compat_BP_PAINTPARAMS *pPaintParams,
                                      ALF_Compat_BP_ANIMATIONPARAMS *pAnimationParams,
                                      HDC *phdcFrom, HDC *phdcTo)
{
    void *p = (void *)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "BeginBufferedAnimation");
    if (!p)
        p = (void*)ALF_Compat_fallbackBeginBufferedAnimation;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_BeginBufferedAnimation, p, (void*)ALF_Compat_loadBeginBufferedAnimation);

    return ALF_Compat_BeginBufferedAnimation(hwnd, hdcTarget, prcTarget, dwFormat, pPaintParams, pAnimationParams, phdcFrom, phdcTo);
}

static HRESULT WINAPI
ALF_Compat_fallbackEndBufferedAnimation(ALF_Compat_HANIMATIONBUFFER hbpAnimation, BOOL fUpdateTarget)
{
    (void)hbpAnimation; (void)fUpdateTarget;

    return E_NOTIMPL;
}

static HRESULT WINAPI
ALF_Compat_loadEndBufferedAnimation(ALF_Compat_HANIMATIONBUFFER hbpAnimation, BOOL fUpdateTarget)
{
    void *p = (void *)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "EndBufferedAnimation");
    if (!p)
        p = (void*)ALF_Compat_fallbackEndBufferedAnimation;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_EndBufferedAnimation, p, (void*)ALF_Compat_loadEndBufferedAnimation);

    return ALF_Compat_EndBufferedAnimation(hbpAnimation, fUpdateTarget);
}

static BOOL WINAPI
ALF_Compat_fallbackBufferedPaintRenderAnimation(HWND hwnd, HDC hdc)
{
    (void)hwnd; (void)hdc;

    return FALSE;
}

static BOOL WINAPI
ALF_Compat_loadBufferedPaintRenderAnimation(HWND hwnd, HDC hdc)
{
    void *p = (void *)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "BufferedPaintRenderAnimation");
    if (!p)
        p = (void *)ALF_Compat_fallbackBufferedPaintRenderAnimation;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_BufferedPaintRenderAnimation, p, (void*)ALF_Compat_loadBufferedPaintRenderAnimation);

    return ALF_Compat_BufferedPaintRenderAnimation(hwnd, hdc);
}

static HRESULT WINAPI
ALF_Compat_fallbackGetThemeTransitionDuration(HTHEME hTheme,
                                              int    iPartId,
                                              int    iStateIdFrom,
                                              int    iStateIdTo,
                                              int    iPropId,
                                              DWORD  *pdwDuration)
{
    (void)hTheme; (void)iPartId; (void)iStateIdFrom; (void)iStateIdTo; (void)iPropId; (void)pdwDuration;

    return E_NOTIMPL;
}

static HRESULT WINAPI
ALF_Compat_loadGetThemeTransitionDuration(HTHEME hTheme,
                                          int    iPartId,
                                          int    iStateIdFrom,
                                          int    iStateIdTo,
                                          int    iPropId,
                                          DWORD  *pdwDuration)
{
    void *p = (void*)GetProcAddress(GetModuleHandleA("uxtheme.dll"), "GetThemeTransitionDuration");

    if (!p)
        p = (void*)ALF_Compat_fallbackGetThemeTransitionDuration;

    InterlockedCompareExchangePointer((void**)&ALF_Compat_GetThemeTransitionDuration, p, (void*)ALF_Compat_loadGetThemeTransitionDuration);

    return ALF_Compat_GetThemeTransitionDuration(hTheme, iPartId, iStateIdFrom, iStateIdTo, iPropId, pdwDuration);
}

BOOL (WINAPI *ALF_Compat_IsAppThemed)(void) = ALF_Compat_loadIsAppThemed;
UINT (WINAPI *ALF_Compat_GetDpiForWindow)(HWND /*window*/) = ALF_Compat_loadGetDpiForWindow;
BOOL (WINAPI *ALF_Compat_AdjustWindowRectExForDpi)(LPRECT,DWORD,BOOL,DWORD,UINT) = ALF_Compat_loadAdjustWindowRectExForDpi;
int (WINAPI *ALF_Compat_GetSystemMetricsForDpi)(int,  UINT) = ALF_Compat_loadGetSystemMetricsForDpi;
BOOL (WINAPI *ALF_Compat_SetWindowSubclass)(HWND, ALF_COMPAT_SUBCLASSPROC, UINT_PTR, DWORD_PTR) = ALF_Compat_loadSetWindowSubclass;
LRESULT (WINAPI *ALF_Compat_DefSubclassProc)(HWND, UINT, WPARAM, LPARAM) = ALF_Compat_loadDefSubclassProc;
BOOL (WINAPI *ALF_Compat_RemoveWindowSubclass)(HWND, ALF_COMPAT_SUBCLASSPROC, UINT_PTR) = ALF_Compat_loadRemoveWindowSubclass;

// FIXME! do Unicode properly for SystemParametersInfoForDpi
#ifdef UNICODE
BOOL (WINAPI *ALF_Compat_SystemParametersInfoForDpi)(UINT,UINT,PVOID,UINT,UINT) = ALF_Compat_loadSystemParametersInfoForDpi;
#else
BOOL (WINAPI *ALF_Compat_SystemParametersInfoForDpi)(UINT,UINT,PVOID,UINT,UINT) = ALF_Compat_fallbackSystemParametersInfoForDpi;
#endif

HTHEME (WINAPI *ALF_Compat_OpenThemeData)(HWND, LPCWSTR) = ALF_Compat_loadOpenThemeData;
HRESULT (WINAPI *ALF_Compat_CloseThemeData)(HTHEME) = ALF_Compat_loadCloseThemeData;
BOOL (WINAPI *ALF_Compat_IsThemeBackgroundPartiallyTransparent)(HTHEME,int,int) = ALF_Compat_loadIsThemeBackgroundPartiallyTransparent;
HRESULT (WINAPI *ALF_Compat_DrawThemeParentBackground)(HWND,HDC,RECT *) = ALF_Compat_loadDrawThemeParentBackground;
HRESULT (WINAPI *ALF_Compat_DrawThemeBackground)(HTHEME, HDC, int, int, const RECT *, const RECT *) = ALF_Compat_loadDrawThemeBackground;
HRESULT (WINAPI *ALF_Compat_GetThemeBackgroundContentRect)(HTHEME,HDC,int,int,const RECT *,RECT *) = ALF_Compat_loadGetThemeBackgroundContentRect;
HRESULT (WINAPI *ALF_Compat_GetThemeTextExtent)(HTHEME,HDC,int,int,LPCWSTR,int,DWORD,const RECT *, RECT *) = ALF_Compat_loadGetThemeTextExtent;
HRESULT (WINAPI *ALF_Compat_DrawThemeText)(HTHEME,HDC,int,int,LPCWSTR,int,DWORD,DWORD,const RECT *) = ALF_Compat_loadDrawThemeText;
BOOL (WINAPI *ALF_Compat_TrackMouseEvent)(LPTRACKMOUSEEVENT tme) = ALF_Compat_loadTrackMouseEvent;
HRESULT (WINAPI *ALF_Compat_BufferedPaintInit)(void) = ALF_Compat_loadBufferedPaintInit;
HRESULT (WINAPI *ALF_Compat_BufferedPaintUnInit)(void) = ALF_Compat_loadBufferedPaintUnInit;
ALF_Compat_HANIMATIONBUFFER (WINAPI *ALF_Compat_BeginBufferedAnimation)(HWND,HDC,const RECT *,DWORD,ALF_Compat_BP_PAINTPARAMS *,ALF_Compat_BP_ANIMATIONPARAMS *,HDC *,HDC *) = ALF_Compat_loadBeginBufferedAnimation;
HRESULT (WINAPI *ALF_Compat_EndBufferedAnimation)(ALF_Compat_HANIMATIONBUFFER,BOOL) = ALF_Compat_loadEndBufferedAnimation;
BOOL (WINAPI *ALF_Compat_BufferedPaintRenderAnimation)(HWND,HDC) = ALF_Compat_loadBufferedPaintRenderAnimation;
HRESULT (WINAPI *ALF_Compat_GetThemeTransitionDuration)(HTHEME,int,int,int,int,DWORD*) = ALF_Compat_loadGetThemeTransitionDuration;