From e9911ec586892bc150dbe39ecc1ecf300d89a6f4 Mon Sep 17 00:00:00 2001
From: Jonas Kümmerlin <jonas@kuemmerlin.eu>
Date: Sat, 23 May 2020 21:25:42 +0200
Subject: rework default button and focus handling

---
 alf/alfwindow.cpp | 109 +++++++++++++++++++++++++++++++++---------------------
 1 file changed, 67 insertions(+), 42 deletions(-)

(limited to 'alf/alfwindow.cpp')

diff --git a/alf/alfwindow.cpp b/alf/alfwindow.cpp
index 64cb6b0..c33a2b4 100644
--- a/alf/alfwindow.cpp
+++ b/alf/alfwindow.cpp
@@ -68,6 +68,66 @@ ALF_UpdateFontsPriv(HWND win, ALFWindowPriv *priv)
     SendMessage(win, WM_SETFONT, (WPARAM)priv->hMessageFont, (LPARAM)1);
 }
 
+static BOOL CALLBACK
+ALF_Window_RemoveDefButton_EnumChildProc(HWND hwnd, LPARAM lParam)
+{
+    HWND keeper = (HWND)lParam;
+    if (hwnd != keeper && (SendMessage(hwnd, WM_GETDLGCODE, 0, 0) & DLGC_DEFPUSHBUTTON)) {
+        SendMessage(hwnd, BM_SETSTYLE, BS_PUSHBUTTON, TRUE);
+    }
+
+    return TRUE;
+}
+
+static void
+ALF_Window_RemoveDefButton(HWND hwnd, ALFWindowPriv *priv, HWND keeper)
+{
+    (void)priv;
+
+    EnumChildWindows(hwnd, ALF_Window_RemoveDefButton_EnumChildProc, (LPARAM)keeper);
+}
+
+static void
+ALF_Window_FixDefButton(HWND hwnd, ALFWindowPriv *priv, HWND prevFocus, HWND currFocus, BOOL force)
+{
+    LRESULT prevCode = prevFocus ? SendMessage(prevFocus, WM_GETDLGCODE, 0, 0) : 0;
+    LRESULT currCode = currFocus ? SendMessage(currFocus, WM_GETDLGCODE, 0, 0) : 0;
+
+    // speed hack: only do something if the focus moves from or to a defaultable button
+    if (!force && !(prevFocus && (prevCode & (DLGC_DEFPUSHBUTTON|DLGC_UNDEFPUSHBUTTON)))
+            && !(currFocus && (currCode & (DLGC_DEFPUSHBUTTON|DLGC_UNDEFPUSHBUTTON))))
+        return;
+
+    // find the target for the new default button
+    HWND newDefBtn = NULL;
+    LRESULT newDefCode = 0;
+    if (currFocus && (currCode & (DLGC_DEFPUSHBUTTON|DLGC_UNDEFPUSHBUTTON))) {
+        newDefBtn = currFocus;
+        newDefCode = currCode;
+    } else {
+        WORD defid = priv->defid != (WORD)-1 ? priv->defid : IDOK;
+        HWND defhwnd = ALF_WidgetHwndById(hwnd, defid);
+        if (defhwnd) {
+            newDefCode = SendMessage(defhwnd, WM_GETDLGCODE, 0, 0);
+            if (newDefCode & (DLGC_DEFPUSHBUTTON|DLGC_UNDEFPUSHBUTTON))
+                newDefBtn = defhwnd;
+        }
+    }
+
+    // speed hack: stop here if the target button is already default
+    // there is supposed to be exactly one default button
+    if (!force && newDefBtn && (newDefCode & DLGC_DEFPUSHBUTTON))
+        return;
+
+    // remove default button style from all other buttons
+    ALF_Window_RemoveDefButton(hwnd, priv, newDefBtn);
+
+    // apply default button style to the new def btn
+    if (newDefBtn && (newDefCode & DLGC_UNDEFPUSHBUTTON)) {
+        SendMessage(newDefBtn, BM_SETSTYLE, BS_DEFPUSHBUTTON, TRUE);
+    }
+}
+
 static void
 ALF_ApplyFocus(HWND hwnd, ALFWindowPriv *priv, BOOL restoringFocus)
 {
@@ -78,26 +138,7 @@ ALF_ApplyFocus(HWND hwnd, ALFWindowPriv *priv, BOOL restoringFocus)
         if (GetForegroundWindow() == hwnd) {
             HWND oldFocus = SetFocus(priv->hwndFocus);
 
-            // FIXME! restore default button state
-            if (oldFocus && SendMessage(oldFocus, WM_GETDLGCODE, 0, 0) & DLGC_DEFPUSHBUTTON) {
-                SendMessage(oldFocus, BM_SETSTYLE, BS_PUSHBUTTON, TRUE);
-            }
-
-            if (priv->defid != (WORD)-1) {
-                HWND hwndOld = ALF_WidgetHwndById(hwnd, priv->defid);
-                if (hwndOld && SendMessage(hwndOld, WM_GETDLGCODE, 0, 0) & DLGC_DEFPUSHBUTTON) {
-                    SendMessage(hwndOld, BM_SETSTYLE, BS_PUSHBUTTON, TRUE);
-                }
-            }
-
-            if (priv->hwndFocus && SendMessage(priv->hwndFocus, WM_GETDLGCODE, 0, 0) & DLGC_UNDEFPUSHBUTTON) {
-                SendMessage(priv->hwndFocus, BM_SETSTYLE, BS_DEFPUSHBUTTON, TRUE);
-            } else {
-                HWND hwndDef = ALF_WidgetHwndById(hwnd, priv->defid);
-                if (hwndDef && SendMessage(hwndDef, WM_GETDLGCODE, 0, 0) & DLGC_UNDEFPUSHBUTTON) {
-                    SendMessage(hwndDef, BM_SETSTYLE, BS_DEFPUSHBUTTON, TRUE);
-                }
-            }
+            ALF_Window_FixDefButton(hwnd, priv, oldFocus, priv->hwndFocus, FALSE);
         }
     } else {
         priv->hwndFocus = GetNextDlgTabItem(hwnd, NULL, FALSE);
@@ -278,18 +319,7 @@ ALF_DefWindowProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
             } else {
                 priv->hwndFocus = GetFocus();
 
-                // FIXME! remove default button state
-                // there has to be a better way to do this
-                if (priv->defid != (WORD)-1) {
-                    HWND hwndDefBtn = ALF_WidgetHwndById(hwnd, priv->defid);
-                    if (hwndDefBtn && SendMessage(hwndDefBtn, WM_GETDLGCODE, 0, 0) & DLGC_DEFPUSHBUTTON) {
-                        SendMessage(hwndDefBtn, BM_SETSTYLE, BS_PUSHBUTTON, TRUE);
-                    }
-                }
-
-                if (priv->hwndFocus && SendMessage(priv->hwndFocus, WM_GETDLGCODE, 0, 0) & DLGC_DEFPUSHBUTTON) {
-                    SendMessage(priv->hwndFocus, BM_SETSTYLE, BS_PUSHBUTTON, TRUE);
-                }
+                ALF_Window_RemoveDefButton(hwnd, priv, NULL);
             }
         }
         return 0;
@@ -383,17 +413,12 @@ ALF_DefWindowProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
         }
     }
     if (msg == DM_SETDEFID) {
-        if (priv->defid != (WORD)-1) {
-            HWND hwndOld = ALF_WidgetHwndById(hwnd, priv->defid);
-            if (hwndOld && SendMessage(hwndOld, WM_GETDLGCODE, 0, 0) & DLGC_DEFPUSHBUTTON) {
-                SendMessage(hwndOld, BM_SETSTYLE, BS_PUSHBUTTON, TRUE);
-            }
-        }
+        WORD newdefid = (WORD)wparam;
+        if (newdefid != priv->defid) {
+            priv->defid = newdefid;
 
-        priv->defid = (WORD)wparam;
-        HWND hwndNew = ALF_WidgetHwndById(hwnd, priv->defid);
-        if (hwndNew && SendMessage(hwndNew, WM_GETDLGCODE, 0, 0) & DLGC_UNDEFPUSHBUTTON) {
-            SendMessage(hwndNew, BM_SETSTYLE, BS_DEFPUSHBUTTON, TRUE);
+            if (GetForegroundWindow() == hwnd)
+                ALF_Window_FixDefButton(hwnd, priv, NULL, GetFocus(), TRUE);
         }
         return TRUE;
     }
-- 
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