From 2a7f4bcd4c04d0e48e580c4b11a94174bc5b09ae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Tue, 19 Jul 2022 11:56:59 +0200
Subject: Implement centered message box.

---
 c/common.cpp | 45 +++++++++++++++++++++++++++++++++++++++++++++
 c/common.h   |  3 +++
 c/main.cpp   | 14 ++++++++------
 3 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/c/common.cpp b/c/common.cpp
index d503133..2259b69 100644
--- a/c/common.cpp
+++ b/c/common.cpp
@@ -57,3 +57,48 @@ Library::~Library()
 {
 	FreeLibrary(m_hModule);
 }
+
+/* Move message box to center of main window. */
+static LRESULT CALLBACK CBTProc(const int nCode, const WPARAM wParam, const LPARAM lParam)
+{
+	extern HWND g_hWnd;
+	if (!g_hWnd || nCode < 0 || nCode != HCBT_ACTIVATE)
+		return CallNextHookEx(0, nCode, wParam, lParam);
+
+	HWND hWnd = (HWND)wParam;
+	if (long lStyle = GetWindowLong(hWnd, GWL_STYLE))
+		if (lStyle & WS_POPUP) {
+			RECT rcMain, rcMsg;
+			GetWindowRect(g_hWnd, &rcMain);
+			GetWindowRect(hWnd, &rcMsg);
+			SetWindowPos(hWnd, NULL,
+			    rcMain.left+(rcMain.right-rcMain.left)/2-(rcMsg.right-rcMsg.left)/2,
+			    rcMain.top+(rcMain.bottom-rcMain.top)/2-(rcMsg.bottom-rcMsg.top)/2,
+			    -1, -1,
+			    SWP_NOZORDER|SWP_NOSIZE|SWP_NOACTIVATE);
+		}
+
+	return 0;
+}
+
+int EBMessageBox(const TCHAR* const tszText, const TCHAR* const tszCaption, const unsigned uType)
+{
+	extern HWND g_hWnd;
+	HHOOK hHook = SetWindowsHookEx(WH_CBT, CBTProc, 0, GetCurrentThreadId());
+	if (!hHook) return 0;
+	MessageBox(g_hWnd, tszText, tszCaption, uType);
+	UnhookWindowsHookEx(hHook);
+	if (!hHook) throw Win32Error(GetLastError());
+	return 0;
+}
+
+int EBMessageBoxA(const char* const szText, const char* const szCaption, const unsigned uType)
+{
+	extern HWND g_hWnd;
+	HHOOK hHook = SetWindowsHookEx(WH_CBT, CBTProc, 0, GetCurrentThreadId());
+	if (!hHook) return 0;
+	MessageBoxA(g_hWnd, szText, szCaption, uType);
+	UnhookWindowsHookEx(hHook);
+	if (!hHook) throw Win32Error(GetLastError());
+	return 0;
+}
diff --git a/c/common.h b/c/common.h
index a4f1fd4..9d14b1d 100644
--- a/c/common.h
+++ b/c/common.h
@@ -11,6 +11,9 @@
 #define WA "A"
 #endif
 
+int EBMessageBox(const TCHAR* tszText, const TCHAR* tszCaption, unsigned uType);
+int EBMessageBoxA(const char* szText, const char* szCaption, unsigned uType);
+
 struct Win32Error : public std::exception
 {
 	Win32Error(DWORD dwErr);
diff --git a/c/main.cpp b/c/main.cpp
index 08e6b96..f7b3472 100644
--- a/c/main.cpp
+++ b/c/main.cpp
@@ -143,10 +143,10 @@ int WINAPI WinMain(const HINSTANCE hInstance, const HINSTANCE, char* const, cons
 	return 0;
 }
 
-static LRESULT CALLBACK CBTProc(const int nCode, const WPARAM wParam, const LPARAM)
+static LRESULT CALLBACK CBTProc(const int nCode, const WPARAM wParam, const LPARAM lParam)
 {
-	if (nCode != HCBT_CREATEWND) return 0;
-	if (g_hWnd) return 0;
+	if (nCode < 0 || nCode != HCBT_CREATEWND || g_hWnd)
+		return CallNextHookEx(0, nCode, wParam, lParam);
 
 	/* This code is run once at the creation of the top-level
 	 * window -- before WndProc! This is important, as it
@@ -198,7 +198,7 @@ LRESULT CALLBACK WndProc(const HWND hWnd, const UINT uMsg, const WPARAM wParam,
 	case WM_CREATE:
 	    {
 		UpdateTheme();
-		SetWindowPos(hWnd, NULL, -1, -1, Dpi(510), Dpi(400), SWP_NOMOVE);
+		SetWindowPos(hWnd, NULL, -1, -1, Dpi(510), Dpi(400), SWP_NOZORDER|SWP_NOMOVE|SWP_NOACTIVATE);
 		SetFocus(g_pElv->hWnd);
 
 		/* Set menu item checkmarks according to saved settings. */
@@ -239,7 +239,7 @@ LRESULT CALLBACK WndProc(const HWND hWnd, const UINT uMsg, const WPARAM wParam,
 		    lpr->left, lpr->top,
 		    lpr->right-lpr->left,
 		    lpr->bottom-lpr->top,
-		    SWP_NOZORDER | SWP_NOACTIVATE);
+		    SWP_NOZORDER|SWP_NOACTIVATE);
 		UpdateLayout();
 		break;
 	    }
@@ -387,7 +387,9 @@ LRESULT CALLBACK WndProc(const HWND hWnd, const UINT uMsg, const WPARAM wParam,
 
 				switch (LOWORD(wParam)) {
 				case IDM_WATCH_LOCALLY:
-					Pl("local_episode","open_episode_locally",lvi.lParam);
+					if (!Pl("local_episode","open_episode_locally",lvi.lParam))
+						EBMessageBox(TEXT("Local episode could not be opened."),
+						    TEXT("Error"), MB_ICONWARNING);
 					break;
 				case IDM_WATCH_ONLINE:
 					Pl("local_episode","open_episode_online",lvi.lParam);
-- 
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