/*
Copyright (c) 2015 Wolfgang 'datenwolf' Draxinger

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
#include "dwm_load.h"

#include <windows.h>
#include <winbase.h>

#define E_INVALID_FUNCTION HRESULT_FROM_WIN32(ERROR_INVALID_FUNCTION)

static void
dwmload_getproc(LPCSTR procname, FARPROC *pp)
{
	if( *pp )  {
		return;
	}

	static HMODULE g_h_dwmapi = NULL;
	if(!g_h_dwmapi) do {
		HMODULE h_dwmapi = NULL;
		if( !GetModuleHandleExA(0, "dwmapi", &h_dwmapi) ) {
			h_dwmapi = LoadLibraryA("dwmapi");
		}
		if( !h_dwmapi ) {
			break;
		}

		/* loading the dwmapi module may trigger a rance
		 * condition if dwmload is used concurrently.
		 * We catch this here, by performing an atomic
		 * compare and exchange here.
		 *
		 * If the C&E returns a not NULL pointer another
		 * thread beat the race; the resolve is to release
		 * the module reference just acquired. */
		if( InterlockedCompareExchangePointer(
			(PVOID volatile *)&g_h_dwmapi,
			(PVOID)h_dwmapi,
			NULL )
		) {
			FreeLibrary(h_dwmapi);
		}
	} while(0);

	FARPROC p = NULL;
	if( g_h_dwmapi ) {
		p = GetProcAddress(g_h_dwmapi, procname);
	}

	/* The compiler should optimize this to a single
	 * unconditional code path. */
	switch(sizeof(FARPROC)) {
	/* 8 bit and 16 bit sizes for FARPROC are quite unlikely,
	 * but we're good and cover these cases as well. */
	case 1:
		InterlockedExchange8((char volatile*)pp, (char)p);
		break;
	case 2:
		InterlockedExchange16((SHORT volatile*)pp, (SHORT)p);
		break;
	case 4:
		InterlockedExchange((LONG volatile*)pp, (LONG)p);
		break;
	case 8:
		InterlockedExchange64((LONGLONG volatile*)pp, (LONGLONG)p);
		break;

	/* practically we should never end up here */
	default:
		InterlockedExchangePointer((PVOID volatile *)pp, (PVOID)p);
		break;
	}
}

BOOL dwmload_DefWindowProc(
    HWND hwnd,
    UINT msg,
    WPARAM wParam,
    LPARAM lParam,
    LRESULT *plResult
)
{
	static BOOL (*p)(HWND, UINT, WPARAM, LPARAM, LRESULT*) = NULL;
	dwmload_getproc("DwmDefWindowProc", (FARPROC*)&p);
	return p ? p(hwnd, msg, wParam, lParam, plResult) : FALSE;
}

HRESULT dwmload_EnableBlurBehindWindow(
    HWND hWnd,
    const DWM_BLURBEHIND *pBlurBehind
)
{
	static HRESULT (*p)(HWND, const DWM_BLURBEHIND*) = NULL;
	dwmload_getproc("DwmEnableBlurBehindWindow", (FARPROC*)&p);
	return p ? p(hWnd, pBlurBehind) : E_INVALID_FUNCTION;
}

HRESULT dwmload_EnableComposition(
    UINT uCompositionAction
)
{
	static HRESULT (*p)(UINT) = NULL;
	dwmload_getproc("DwmEnableComposition", (FARPROC*)&p);
	return p ? p(uCompositionAction) : E_INVALID_FUNCTION;
}

HRESULT dwmload_EnableMMCSS(
    BOOL fEnableMMCSS
)
{
	static HRESULT (*p)(BOOL) = NULL;
	dwmload_getproc("DwmEnableMMCSS", (FARPROC*)&p);
	return p ? p(fEnableMMCSS) : E_INVALID_FUNCTION;
}

HRESULT dwmload_ExtendFrameIntoClientArea(
    HWND hWnd,
    const MARGINS *pMarInset
)
{
	static HRESULT (*p)(HWND, const MARGINS*) = NULL;
	dwmload_getproc("DwmExtendFrameIntoClientArea", (FARPROC*)&p);
	return p ? p(hWnd, pMarInset) : E_INVALID_FUNCTION;
}

HRESULT dwmload_GetColorizationColor(
    DWORD *pcrColorization,
    BOOL *pfOpaqueBlend
)
{
	static HRESULT (*p)(DWORD*, BOOL*) = NULL;
	dwmload_getproc("DwmGetColorizationColor", (FARPROC*)&p);
	/* TODO: Implement Fallback that returns GDI system colors */
	return p ? p(pcrColorization, pfOpaqueBlend) : E_INVALID_FUNCTION;
}

HRESULT dwmload_GetCompositionTimingInfo(
    HWND hwnd,
    DWM_TIMING_INFO *pTimingInfo
)
{
	static HRESULT (*p)(HWND, DWM_TIMING_INFO*) = NULL;
	dwmload_getproc("DwmGetCompositionTimingInfo", (FARPROC*)&p);
	return p ? p(hwnd, pTimingInfo) : E_INVALID_FUNCTION;
}

HRESULT dwmload_GetWindowAttribute(
    HWND hwnd,
    DWORD dwAttribute,
    PVOID pvAttribute,
    DWORD cbAttribute
)
{
	static HRESULT (*p)(HWND, DWORD, PVOID, DWORD) = NULL;
	dwmload_getproc("DwmGetWindowAttribute", (FARPROC*)&p);
	if(!p) {
		memset(pvAttribute, 0, cbAttribute);
	}
	return p ? p(hwnd, dwAttribute, pvAttribute, cbAttribute) : E_INVALID_FUNCTION;
}

HRESULT dwmload_IsCompositionEnabled(
    BOOL *pfEnabled
)
{
	static HRESULT (*p)(BOOL*) = NULL;
	dwmload_getproc("DwmIsCompositionEnabled", (FARPROC*)&p);
	if(!p) {
		*pfEnabled = FALSE;
	}
	/* Don't return a error if DWM API is not available;
	 * it makes sense to inform the program, that composition
	 * is not enabled ony a system that does not support
	 * composition. */
	return p ? p(pfEnabled) : S_OK;
}

HRESULT dwmload_ModifyPreviousDxFrameDuration(
    HWND hwnd,
    INT cRefreshes,
    BOOL fRelative
)
{
	static HRESULT (*p)(HWND, INT, BOOL) = NULL;
	dwmload_getproc("DwmModifyPreviousDxFrameDuration", (FARPROC*)&p);
	return p ? p(hwnd, cRefreshes, fRelative) : S_OK;
}


HRESULT dwmload_QueryThumbnailSourceSize(
    HTHUMBNAIL hThumbnail,
    PSIZE pSize
)
{
	static HRESULT (*p)(HTHUMBNAIL, PSIZE) = NULL;
	dwmload_getproc("DwmQueryThumbnailSourceSize", (FARPROC*)&p);
	if(!p) {
		memset(pSize, 0, sizeof(*pSize));
	}
	return p ? p(hThumbnail, pSize) : E_INVALID_FUNCTION;
}

HRESULT dwmload_RegisterThumbnail(
    HWND hwndDestination,
    HWND *hwndSource,
    PHTHUMBNAIL phThumbnailId
)
{
	static HRESULT (*p)(HWND, HWND*, PHTHUMBNAIL) = NULL;
	dwmload_getproc("DwmRegisterThumbnail", (FARPROC*)&p);
	if(!p) {
		if( phThumbnailId) *phThumbnailId = NULL;
	}
	return p ? p(hwndDestination, hwndSource, phThumbnailId) : E_INVALID_FUNCTION;
}

HRESULT dwmload_SetDxFrameDuration(
    HWND hwnd,
    INT cRefreshes
)
{
	static HRESULT (*p)(HWND, INT) = NULL;
	dwmload_getproc("DwmSetDxFrameDuration", (FARPROC*)&p);
	return p ? p(hwnd, cRefreshes) : S_OK;
}

HRESULT dwmload_SetPresentParameters(
    HWND hwnd,
    DWM_PRESENT_PARAMETERS *pPresentParams
)
{
	static HRESULT (*p)(HWND, DWM_PRESENT_PARAMETERS*) = NULL;
	dwmload_getproc("DwmSetPresentParameters", (FARPROC*)&p);
	return p ? p(hwnd, pPresentParams) : S_OK;
}

HRESULT dwmload_SetWindowAttribute(
    HWND hwnd,
    DWORD dwAttribute,
    LPCVOID pvAttribute,
    DWORD cbAttribute
)
{
	static HRESULT (*p)(HWND, DWORD, LPCVOID, DWORD) = NULL;
	dwmload_getproc("DwmSetWindowAttribute", (FARPROC*)&p);
	return p ? p(hwnd, dwAttribute, pvAttribute, cbAttribute) : S_OK;
}

HRESULT dwmload_UnregisterThumbnail(
    HTHUMBNAIL hThumbnailId
)
{
	static HRESULT (*p)(HTHUMBNAIL) = NULL;
	dwmload_getproc("DwmUnregisterThumbnail", (FARPROC*)&p);
	return p ? p(hThumbnailId) : S_OK;
}

HRESULT dwmload_UpdateThumbnailProperties(
    HTHUMBNAIL hThumbnailId,
    const DWM_THUMBNAIL_PROPERTIES *ptnProperties
)
{
	static HRESULT (*p)(HTHUMBNAIL, const DWM_THUMBNAIL_PROPERTIES*) = NULL;
	dwmload_getproc("DwmUpdateThumbnailProperties", (FARPROC*)&p);
	return p ? p(hThumbnailId, ptnProperties) : S_OK;
}