Add automatic appearance theme pairs

MacDown/Code/Application/MPMainController.m

@@ -24,6 +24,9 @@
 
 
 static NSString * const kMPTreatLastSeenStampKey = @"treatLastSeenStamp";
+static NSString * const kMPViewMenuTitle = @"View";
+static NSString * const kMPFollowSystemAppearanceMenuItemTitle =
+    @"Follow System Appearance";
 
 
 NS_INLINE void MPOpenBundledFile(NSString *resource, NSString *extension)
@@ -97,7 +100,7 @@ NS_INLINE void treat()
 }
 
 
-@interface MPMainController ()
+@interface MPMainController () <NSMenuItemValidation>
 @property (readonly) NSWindowController *preferencesWindowController;
 @end
 
@@ -112,6 +115,7 @@ - (void)applicationDidFinishLaunching:(NSNotification *)notification
         setEventHandler:self
             andSelector:@selector(openUrlSchemeAppleEvent:withReplyEvent:)
           forEventClass:kInternetEventClass andEventID:kAEGetURL];
+    [self installAppearanceThemeMenuItem];
 }
 
 // Open a file from a browser with url of the form :
@@ -216,6 +220,26 @@ - (IBAction)openGitHub:(id)sender
     [[NSWorkspace sharedWorkspace] openURL:url];
 }
 
+- (IBAction)toggleAppearanceThemesFollowSystem:(id)sender
+{
+    MPPreferences *preferences = self.preferences;
+    preferences.appearanceThemesFollowSystem =
+        !preferences.appearanceThemesFollowSystem;
+}
+
+
+#pragma mark - NSMenuItemValidation
+
+- (BOOL)validateMenuItem:(NSMenuItem *)menuItem
+{
+    if (menuItem.action == @selector(toggleAppearanceThemesFollowSystem:))
+    {
+        menuItem.state = self.preferences.appearanceThemesFollowSystem ?
+            NSControlStateValueOn : NSControlStateValueOff;
+    }
+    return YES;
+}
+
 
 #pragma mark - Override
 
@@ -307,6 +331,28 @@ - (void)copyFiles
     }
 }
 
+- (void)installAppearanceThemeMenuItem
+{
+    NSMenuItem *viewItem = [NSApp.mainMenu itemWithTitle:kMPViewMenuTitle];
+    NSMenu *viewMenu = viewItem.submenu;
+    if (!viewMenu)
+        return;
+
+    SEL action = @selector(toggleAppearanceThemesFollowSystem:);
+    for (NSMenuItem *item in viewMenu.itemArray)
+    {
+        if (item.action == action)
+            return;
+    }
+
+    [viewMenu addItem:[NSMenuItem separatorItem]];
+    NSMenuItem *item =
+        [[NSMenuItem alloc] initWithTitle:kMPFollowSystemAppearanceMenuItemTitle
+                                   action:action keyEquivalent:@""];
+    item.target = self;
+    [viewMenu addItem:item];
+}
+
 - (void)openPendingFiles
 {
     NSDocumentController *c = [NSDocumentController sharedDocumentController];

MacDown/Code/Document/MPDocument.m

@@ -37,6 +37,8 @@
 #import <JavaScriptCore/JavaScriptCore.h>
 
 static NSString * const kMPDefaultAutosaveName = @"Untitled";
+static NSString * const kMPAppleInterfaceThemeChangedNotification =
+    @"AppleInterfaceThemeChangedNotification";
 
 
 NS_INLINE NSString *MPEditorPreferenceKeyWithValueKey(NSString *key)
@@ -76,6 +78,8 @@
             @"editorHorizontalInset", @"editorVerticalInset",
             @"editorWidthLimited", @"editorMaximumWidth", @"editorLineSpacing",
             @"editorOnRight", @"editorStyleName", @"editorShowWordCount",
+            @"appearanceThemesFollowSystem", @"editorLightStyleName",
+            @"editorDarkStyleName",
             @"editorScrollsPastEnd",
             @"htmlMathJax", @"htmlMathJaxInlineDollar", nil
         ];
@@ -535,6 +539,9 @@ - (void)windowControllerDidLoadNib:(NSWindowController *)controller
     [center addObserver:self selector:@selector(previewBoundsDidChange:)
                    name:NSViewBoundsDidChangeNotification
                  object:self.preview.enclosingScrollView.contentView];
+    [[NSDistributedNotificationCenter defaultCenter]
+        addObserver:self selector:@selector(applicationAppearanceDidChange:)
+               name:kMPAppleInterfaceThemeChangedNotification object:nil];
 
     self.needsToUnregister = YES;
 
@@ -654,6 +661,7 @@ - (void)close
         }
 
         [[NSNotificationCenter defaultCenter] removeObserver:self];
+        [[NSDistributedNotificationCenter defaultCenter] removeObserver:self];
 
         NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
 
@@ -1323,7 +1331,7 @@ - (BOOL)rendererRendersTOC:(MPRenderer *)renderer
 
 - (NSString *)rendererStyleName:(MPRenderer *)renderer
 {
-    return self.preferences.htmlStyleName;
+    return self.preferences.effectiveHtmlStyleName;
 }
 
 - (BOOL)rendererDetectsFrontMatter:(MPRenderer *)renderer
@@ -1398,7 +1406,7 @@ - (void)renderer:(MPRenderer *)renderer didProduceHTMLOutput:(NSString *)html
 
     // Check if CSS style or highlighting theme has changed.
     // If either changed, we must do a full reload to update <head> with new CSS links.
-    NSString *newStyleName = self.preferences.htmlStyleName;
+    NSString *newStyleName = self.preferences.effectiveHtmlStyleName;
     NSString *newHighlightingTheme = self.preferences.htmlHighlightingThemeName;
     BOOL stylesChanged = !MPAreNilableStringsEqual(self.currentStyleName, newStyleName) ||
                          !MPAreNilableStringsEqual(self.currentHighlightingThemeName, newHighlightingTheme);
@@ -1689,6 +1697,15 @@ - (void)didRequestPreviewReload:(NSNotification *)notification
     [self render:nil];
 }
 
+- (void)applicationAppearanceDidChange:(NSNotification *)notification
+{
+    if (!self.preferences.appearanceThemesFollowSystem)
+        return;
+
+    [self setupEditor:nil];
+    [self.renderer renderIfPreferencesChanged];
+}
+
 - (void)previewBoundsDidChange:(NSNotification *)notification
 {
     // Issue #342: Only trigger reverse sync when the user is explicitly scrolling
@@ -1757,7 +1774,7 @@ - (IBAction)exportHtml:(id)sender
 
     MPExportPanelAccessoryViewController *controller =
         [[MPExportPanelAccessoryViewController alloc] init];
-    controller.stylesIncluded = (BOOL)self.preferences.htmlStyleName;
+    controller.stylesIncluded = (BOOL)self.preferences.effectiveHtmlStyleName;
     controller.highlightingIncluded = self.preferences.htmlSyntaxHighlighting;
     panel.accessoryView = controller.view;
 
@@ -2159,6 +2176,9 @@ - (void)setupEditor:(NSString *)changedKey
 
     if (!changedKey || [changedKey isEqualToString:@"editorBaseFontInfo"]
             || [changedKey isEqualToString:@"editorStyleName"]
+            || [changedKey isEqualToString:@"appearanceThemesFollowSystem"]
+            || [changedKey isEqualToString:@"editorLightStyleName"]
+            || [changedKey isEqualToString:@"editorDarkStyleName"]
             || [changedKey isEqualToString:@"editorLineSpacing"])
     {
         NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
@@ -2192,15 +2212,17 @@ - (void)setupEditor:(NSString *)changedKey
         self.highlighter.styles = nil;
         [self.highlighter readClearTextStylesFromTextView];
 
-        NSString *themeName = [self.preferences.editorStyleName copy];
+        NSString *themeName = [self.preferences.effectiveEditorStyleName copy];
         if (themeName.length)
         {
             NSString *path = MPThemePathForName(themeName);
             NSString *themeString = MPReadFileOfPath(path);
             [self.highlighter applyStylesFromStylesheet:themeString
                                        withErrorHandler:
                 ^(NSArray *errorMessages) {
-                    self.preferences.editorStyleName = nil;
+                    [self.preferences setEditorStyleName:nil
+                                       forDarkAppearance:
+                        self.preferences.usesDarkSystemAppearance];
                 }];
         }
 

MacDown/Code/Preferences/MPEditorPreferencesViewController.m

@@ -76,7 +76,7 @@ - (void)loadThemes
     [self.themeSelect addItemWithTitle:@""];
     [self.themeSelect addItemsWithTitles:itemTitles];
 
-    NSString *title = [self.preferences.editorStyleName copy];
+    NSString *title = [self.preferences.effectiveEditorStyleName copy];
     if (title.length)
         [self.themeSelect selectItemWithTitle:title];
 
@@ -123,10 +123,17 @@ - (IBAction)changeTheme:(NSPopUpButton *)sender
     NSString *title = sender.selectedItem.title;
 
     // Special case: the first (empty) item. No stylesheets will be used.
-    if (!title.length)
-        self.preferences.editorStyleName = nil;
+    NSString *styleName = title.length ? title : nil;
+    if (self.preferences.appearanceThemesFollowSystem)
+    {
+        [self.preferences setEditorStyleName:styleName
+                           forDarkAppearance:
+            self.preferences.usesDarkSystemAppearance];
+    }
     else
-        self.preferences.editorStyleName = title;
+    {
+        self.preferences.editorStyleName = styleName;
+    }
 }
 
 - (IBAction)invokeStylesheetFunction:(NSSegmentedControl *)sender

MacDown/Code/Preferences/MPHtmlPreferencesViewController.m

@@ -61,10 +61,17 @@ - (IBAction)changeStylesheet:(NSPopUpButton *)sender
     NSString *title = sender.selectedItem.title;
 
     // Special case: the first (empty) item. No stylesheets will be used.
-    if (!title.length)
-        self.preferences.htmlStyleName = nil;
+    NSString *styleName = title.length ? title : nil;
+    if (self.preferences.appearanceThemesFollowSystem)
+    {
+        [self.preferences setHtmlStyleName:styleName
+                         forDarkAppearance:
+            self.preferences.usesDarkSystemAppearance];
+    }
     else
-        self.preferences.htmlStyleName = title;
+    {
+        self.preferences.htmlStyleName = styleName;
+    }
 }
 
 - (IBAction)changeHighlightingTheme:(NSPopUpButton *)sender
@@ -153,7 +160,7 @@ - (void)loadStylesheets
     [self.stylesheetSelect addItemWithTitle:@""];
     [self.stylesheetSelect addItemsWithTitles:itemTitles];
 
-    NSString *title = self.preferences.htmlStyleName;
+    NSString *title = self.preferences.effectiveHtmlStyleName;
     if (title.length)
         [self.stylesheetSelect selectItemWithTitle:title];
 

MacDown/Code/Preferences/MPPreferences.h

@@ -43,6 +43,9 @@ extern NSString * const MPDidDetectFreshInstallationNotification;
 @property (assign) BOOL editorSyncScrolling;
 @property (assign) BOOL editorSmartHome;
 @property (assign) NSString *editorStyleName;
+@property (assign) BOOL appearanceThemesFollowSystem;
+@property (assign) NSString *editorLightStyleName;
+@property (assign) NSString *editorDarkStyleName;
 @property (assign) CGFloat editorHorizontalInset;
 @property (assign) CGFloat editorVerticalInset;
 @property (assign) CGFloat editorLineSpacing;
@@ -61,6 +64,8 @@ extern NSString * const MPDidDetectFreshInstallationNotification;
 
 @property (assign) NSString *htmlTemplateName;
 @property (assign) NSString *htmlStyleName;
+@property (assign) NSString *htmlLightStyleName;
+@property (assign) NSString *htmlDarkStyleName;
 @property (assign) BOOL htmlDetectFrontMatter;
 @property (assign) BOOL htmlTaskList;
 @property (assign) BOOL htmlHardWrap;
@@ -80,8 +85,17 @@ extern NSString * const MPDidDetectFreshInstallationNotification;
 @property (readonly) CGFloat editorBaseFontSize;
 @property (nonatomic, assign) NSFont *editorBaseFont;
 @property (readonly) NSString *editorUnorderedListMarker;
+@property (readonly) NSString *effectiveEditorStyleName;
+@property (readonly) NSString *effectiveHtmlStyleName;
 
 - (instancetype)init;
+- (BOOL)usesDarkSystemAppearance;
+- (NSString *)editorStyleNameForDarkAppearance:(BOOL)darkAppearance;
+- (NSString *)htmlStyleNameForDarkAppearance:(BOOL)darkAppearance;
+- (void)setEditorStyleName:(NSString *)styleName
+         forDarkAppearance:(BOOL)darkAppearance;
+- (void)setHtmlStyleName:(NSString *)styleName
+       forDarkAppearance:(BOOL)darkAppearance;
 
 // Convinience methods.
 @property (nonatomic, assign) NSArray *filesToOpen;