3 files changed, 81 insertions, 6 deletions

diff --git a/src/app.c b/src/app.c
index 670adee2..3eb090a6 100644
--- a/src/app.c
+++ b/src/app.c
@@ -70,6 +70,7 @@ struct Impl_App {
     float        uiScale;
     int          zoomPercent;
     enum iColorTheme theme;
+    iBool        useSystemTheme;
 };
 
 static iApp app_;
@@ -113,7 +114,8 @@ static iString *serializePrefs_App_(const iApp *d) {
     appendFormat_String(str, "sidebar.mode arg:%d\n", mode_SidebarWidget(sidebar));
     appendFormat_String(str, "uiscale arg:%f\n", uiScale_Window(d->window));
     appendFormat_String(str, "zoom.set arg:%d\n", d->zoomPercent);
-    appendFormat_String(str, "theme.set arg:%d\n", d->theme);
+    appendFormat_String(str, "theme.set arg:%d auto:1\n", d->theme);
+    appendFormat_String(str, "ostheme arg:%d\n", d->useSystemTheme);
     return str;
 }
 
@@ -234,6 +236,7 @@ static void init_App_(iApp *d, int argc, char **argv) {
     d->commandEcho       = checkArgument_CommandLine(&d->args, "echo") != NULL;
     d->initialWindowRect = init_Rect(-1, -1, 800, 500);
     d->theme             = dark_ColorTheme;
+    d->useSystemTheme    = iTrue;
     d->running           = iFalse;
     d->window            = NULL;
     d->retainWindowSize  = iTrue;
@@ -452,11 +455,20 @@ static iBool handlePrefsCommands_(iWidget *d, const char *cmd) {
                           toFloat_String(text_InputWidget(findChild_Widget(d, "prefs.uiscale"))));
         postCommandf_App("retainwindow arg:%d",
                          isSelected_Widget(findChild_Widget(d, "prefs.retainwindow")));
+        postCommandf_App("ostheme arg:%d",
+                         isSelected_Widget(findChild_Widget(d, "prefs.ostheme")));
         destroy_Widget(d);
         return iTrue;
     }
-    else if (equal_Command(cmd, "theme.changed")) {
+    else if (equal_Command(cmd, "prefs.ostheme.changed")) {
+        //setToggle_Widget(findChild_Widget(d, "prefs.ostheme"), arg_Command(cmd));
+        postCommandf_App("ostheme arg:%d", arg_Command(cmd));
+    }
+    else if (equal_Command(cmd, "theme.changed")) {        
         updatePrefsThemeButtons_(d);
+        if (!argLabel_Command(cmd, "auto")) {
+            setToggle_Widget(findChild_Widget(d, "prefs.ostheme"), iFalse);
+        }
     }
     return iFalse;
 }
@@ -601,6 +613,7 @@ iBool handleCommand_App(const char *cmd) {
     else if (equal_Command(cmd, "preferences")) {
         iWidget *dlg = makePreferences_Widget();
         updatePrefsThemeButtons_(dlg);
+        setToggle_Widget(findChild_Widget(dlg, "prefs.ostheme"), d->useSystemTheme);
         setToggle_Widget(findChild_Widget(dlg, "prefs.retainwindow"), d->retainWindowSize);
         setText_InputWidget(findChild_Widget(dlg, "prefs.uiscale"),
                             collectNewFormat_String("%g", uiScale_Window(d->window)));
@@ -641,11 +654,29 @@ iBool handleCommand_App(const char *cmd) {
         return iTrue;
     }
     else if (equal_Command(cmd, "theme.set")) {
+        const int isAuto = argLabel_Command(cmd, "auto");
         d->theme = arg_Command(cmd);
+        if (!isAuto) {
+            postCommand_App("ostheme arg:0");
+        }
         setThemePalette_Color(d->theme);
-        postCommand_App("theme.changed");
+        postCommandf_App("theme.changed auto:%d", isAuto);
+        return iTrue;
+    }
+    else if (equal_Command(cmd, "ostheme")) {
+        d->useSystemTheme = arg_Command(cmd);
         return iTrue;
     }
+    else if (equal_Command(cmd, "os.theme.changed")) {
+        if (d->useSystemTheme) {
+            const int dark     = argLabel_Command(cmd, "dark");
+            const int contrast = argLabel_Command(cmd, "contrast");
+            postCommandf_App("theme.set arg:%d auto:1",
+                             dark ? (contrast ? pureBlack_ColorTheme : dark_ColorTheme)
+                                  : (contrast ? pureWhite_ColorTheme : light_ColorTheme));
+        }
+        return iFalse;
+    }
     else {
         return iFalse;
     }
diff --git a/src/ui/macos.m b/src/ui/macos.m
index 9ff2f96e..75a3ffe4 100644
--- a/src/ui/macos.m
+++ b/src/ui/macos.m
@@ -91,6 +91,7 @@ enum iTouchBarVariant {
 
 @interface MyDelegate : NSResponder<NSApplicationDelegate, NSTouchBarDelegate> {
     enum iTouchBarVariant touchBarVariant;
+    NSString *currentAppearanceName;
     NSObject<NSApplicationDelegate> *sdlDelegate;
     NSMutableDictionary<NSString *, NSString*> *menuCommands;
 }
@@ -105,6 +106,7 @@ enum iTouchBarVariant {
 
 - (id)initWithSDLDelegate:(NSObject<NSApplicationDelegate> *)sdl {
     [super init];
+    currentAppearanceName = nil;
     menuCommands = [[NSMutableDictionary<NSString *, NSString *> alloc] init];
     touchBarVariant = default_TouchBarVariant;
     sdlDelegate = sdl;
@@ -113,6 +115,7 @@ enum iTouchBarVariant {
 
 - (void)dealloc {
     [menuCommands release];
+    [currentAppearanceName release];
     [super dealloc];
 }
 
@@ -121,6 +124,24 @@ enum iTouchBarVariant {
     self.touchBar = nil;
 }
 
+static void appearanceChanged_MacOS_(NSString *name) {
+    const iBool isDark = [name containsString:@"Dark"];
+    const iBool isHighContrast = [name containsString:@"HighContrast"];
+    postCommandf_App("os.theme.changed dark:%d contrast:%d", isDark ? 1 : 0, isHighContrast ? 1 : 0);
+    printf("Effective appearance changed: %s\n", [name cStringUsingEncoding:NSUTF8StringEncoding]);
+    fflush(stdout);
+}
+
+- (void)setAppearance:(NSString *)name {
+    if (!currentAppearanceName || ![name isEqualToString:currentAppearanceName]) {
+        if (currentAppearanceName) {
+            [currentAppearanceName release];
+        }
+        currentAppearanceName = [name retain];
+        appearanceChanged_MacOS_(currentAppearanceName);
+    }
+}
+
 - (void)setCommand:(NSString *)command forMenuItem:(NSMenuItem *)menuItem {
     [menuCommands setObject:command forKey:[menuItem title]];
 }
@@ -133,6 +154,16 @@ enum iTouchBarVariant {
     [sdlDelegate applicationDidFinishLaunching:notification];
 }
 
+- (void)observeValueForKeyPath:(NSString *)keyPath
+                      ofObject:(id)object
+                        change:(NSDictionary *)change
+                       context:(void *)context {
+    iUnused(object, change);
+    if ([keyPath isEqualToString:@"effectiveAppearance"] && context == self) {
+        [self setAppearance:[[NSApp effectiveAppearance] name]];
+    }
+}
+
 #if 0
 - (NSTouchBar *)makeTouchBar {
     NSTouchBar *bar = [[NSTouchBar alloc] init];
@@ -344,8 +375,10 @@ void enableMomentumScroll_MacOS(void) {
 
 void setupApplication_MacOS(void) {
     NSApplication *app = [NSApplication sharedApplication];
+    //appearanceChanged_MacOS_([[app effectiveAppearance] name]);
     /* Our delegate will override SDL's delegate. */
     MyDelegate *myDel = [[MyDelegate alloc] initWithSDLDelegate:app.delegate];
+    [myDel setAppearance:[[app effectiveAppearance] name]];
     app.delegate = myDel;
     NSMenu *appMenu = [[[NSApp mainMenu] itemAtIndex:0] submenu];
     NSMenuItem *prefsItem = [appMenu itemWithTitle:@"Preferences…"];
@@ -361,6 +394,10 @@ void setupApplication_MacOS(void) {
 void insertMenuItems_MacOS(const char *menuLabel, int atIndex, const iMenuItem *items, size_t count) {
     NSApplication *app = [NSApplication sharedApplication];
     MyDelegate *myDel = (MyDelegate *) app.delegate;
+    [app addObserver:myDel
+          forKeyPath:@"effectiveAppearance"
+             options:0
+             context:myDel];
     NSMenu *appMenu = [app mainMenu];
     NSMenuItem *mainItem = [appMenu insertItemWithTitle:[NSString stringWithUTF8String:menuLabel]
                                                  action:nil
@@ -417,6 +454,11 @@ void insertMenuItems_MacOS(const char *menuLabel, int atIndex, const iMenuItem *
 }
 
 void handleCommand_MacOS(const char *cmd) {
+    if (equal_Command(cmd, "prefs.ostheme.changed")) {
+        if (arg_Command(cmd)) {
+            appearanceChanged_MacOS_([[NSApp effectiveAppearance] name]);
+        }
+    }
 #if 0
     if (equal_Command(cmd, "tabs.changed")) {
         MyDelegate *myDel = (MyDelegate *) [[NSApplication sharedApplication] delegate];
diff --git a/src/ui/util.c b/src/ui/util.c
index 9f4768d9..918a0671 100644
--- a/src/ui/util.c
+++ b/src/ui/util.c
@@ -702,9 +702,11 @@ iWidget *makePreferences_Widget(void) {
         page, iClob(new_Widget()), arrangeVertical_WidgetFlag | arrangeSize_WidgetFlag);    
     iWidget *values = addChildFlags_Widget(
         page, iClob(new_Widget()), arrangeVertical_WidgetFlag | arrangeSize_WidgetFlag);
-//    setBackgroundColor_Widget(headings, none_ColorId);
-//    setBackgroundColor_Widget(values, none_ColorId);
-    addChild_Widget(headings, iClob(makeHeading_Widget("Theme:")));
+#if defined (iPlatformApple) || defined (iPlatformMSys)
+    addChild_Widget(headings, iClob(makeHeading_Widget("Use system theme:")));
+    addChild_Widget(values, iClob(makeToggle_Widget("prefs.ostheme")));
+#endif
+    addChild_Widget(headings, iClob(makeHeading_Widget("Theme:")));    
     iWidget *themes = new_Widget();
     /* Themes. */ {
         setId_Widget(addChild_Widget(themes, iClob(new_LabelWidget("Pure Black", 0, 0, "theme.set arg:0"))), "prefs.theme.0");