Add themes support

Usage:

  const editor = new RibbitEditor({
    themes: [
        { name: 'dark', features: { sourceMode: false } },
        { name: 'minimal', tags: minimalTags },
    ],
    currentTheme: 'dark',
  });

The built-in theme is 'ribbit-default' and is always available.
Additional themes from the themes array are registered on top.

src/ribbit.css

@@ -1,58 +0,0 @@
-/*
- * ribbit.css — editor styles for the ribbit WYSIWYG markdown editor.
- *
- * Provides base content formatting and editor state styles.
- * Override with your own theme CSS for custom look and feel.
- */
-
-/* ── Content formatting ──────────────────────────────── */
-
-a { text-decoration: none; }
-
-q, blockquote {
-    margin-left: 30px;
-    font-size: 1.3em;
-    font-style: italic;
-    color: #555;
-}
-
-table { width: 100%; }
-th { border-bottom: 1px solid #000; padding: 3px; }
-th, td { padding: 2px; }
-table td table { max-width: 95%; }
-
-pre {
-    border: 1px dashed black;
-    border-radius: 5px;
-    padding: 10px;
-    margin: 5px;
-    background: #EEE;
-}
-
-code {
-    display: inline-block;
-    border: 1px dashed black;
-    border-radius: 5px;
-    padding: 5px;
-    background: #EEE;
-    margin: 3px;
-}
-
-/* ── Editor states ───────────────────────────────────── */
-
-#ribbit {
-    display: none;
-}
-
-#ribbit.loaded {
-    display: block;
-}
-
-#ribbit.edit {
-    font-family: monospace;
-    white-space: pre;
-}
-
-#ribbit.wysiwyg .md {
-    opacity: 0.5;
-}

src/static/ribbit-core.css

@@ -0,0 +1,22 @@
+/*
+ * ribbit-core.css — functional editor styles. Always load this.
+ * These styles control editor state visibility and behavior.
+ * They should not be overridden by themes.
+ */
+
+#ribbit {
+    display: none;
+}
+
+#ribbit.loaded {
+    display: block;
+}
+
+#ribbit.edit {
+    font-family: monospace;
+    white-space: pre;
+}
+
+#ribbit.wysiwyg .md {
+    opacity: 0.5;
+}

src/static/themes/ribbit-default/theme.css

@@ -0,0 +1,52 @@
+/*
+ * default.css — the default ribbit theme.
+ * Provides basic aesthetic styling for rendered markdown content.
+ * Replace this file with your own theme to customize the look.
+ */
+
+@import "../ribbit-core.css";
+
+a {
+    text-decoration: none;
+}
+
+blockquote {
+    margin-left: 30px;
+    font-size: 1.3em;
+    font-style: italic;
+    color: #555;
+}
+
+table {
+    width: 100%;
+}
+
+th {
+    border-bottom: 1px solid #000;
+    padding: 3px;
+}
+
+th, td {
+    padding: 2px;
+}
+
+table td table {
+    max-width: 95%;
+}
+
+pre {
+    border: 1px dashed black;
+    border-radius: 5px;
+    padding: 10px;
+    margin: 5px;
+    background: #EEE;
+}
+
+code {
+    display: inline-block;
+    border: 1px dashed black;
+    border-radius: 5px;
+    padding: 5px;
+    background: #EEE;
+    margin: 3px;
+}

src/ts/default-theme.ts

@@ -0,0 +1,16 @@
+/*
+ * default-theme.ts — the default ribbit theme.
+ *
+ * Enables all default tags and all editor features.
+ */
+
+import type { RibbitTheme } from './types';
+import { defaultTags } from './tags';
+
+export const defaultTheme: RibbitTheme = {
+    name: 'ribbit-default',
+    tags: defaultTags,
+    features: {
+        sourceMode: true,
+    },
+};

src/ts/ribbit-editor.ts

@@ -2,9 +2,9 @@
  * ribbit-editor.ts — WYSIWYG editing extension for Ribbit.
  */
 
-import hopdown from './hopdown';
 import { HopDown } from './hopdown';
 import { defaultTags, defaultBlockTags, defaultInlineTags, inlineTag } from './tags';
+import { defaultTheme } from './default-theme';
 import { Ribbit, RibbitPlugin, RibbitSettings, camelCase, decodeHtmlEntities, encodeHtmlEntities } from './ribbit';
 
 /**
@@ -46,7 +46,7 @@ export class RibbitEditor extends Ribbit {
     }
 
     htmlToMarkdown(html?: string): string {
-        return hopdown.toMarkdown(html || this.element.innerHTML);
+        return this.converter.toMarkdown(html || this.element.innerHTML);
     }
 
     getMarkdown(): string {
@@ -80,6 +80,9 @@ export class RibbitEditor extends Ribbit {
     }
 
     edit(): void {
+        if (!this.theme.features?.sourceMode) {
+            return;
+        }
         if (this.state === this.states.EDIT) return;
         this.changed = false;
         this.element.contentEditable = 'true';
@@ -101,11 +104,11 @@ export class RibbitEditor extends Ribbit {
 
 // Attach public API to window for <script> tag usage.
 (window as any).HopDown = HopDown;
-(window as any).hopdown = hopdown;
 (window as any).inlineTag = inlineTag;
 (window as any).defaultTags = defaultTags;
 (window as any).defaultBlockTags = defaultBlockTags;
 (window as any).defaultInlineTags = defaultInlineTags;
+(window as any).defaultTheme = defaultTheme;
 (window as any).Ribbit = Ribbit;
 (window as any).RibbitEditor = RibbitEditor;
 (window as any).RibbitPlugin = RibbitPlugin;

src/ts/ribbit.ts

@@ -2,12 +2,18 @@
  * ribbit.ts — core editor classes for the ribbit WYSIWYG markdown editor.
  */
 
-import hopdown from './hopdown';
+import { HopDown } from './hopdown';
+import { defaultTheme } from './default-theme';
+import { ThemeManager } from './theme-manager';
+import type { RibbitTheme } from './types';
 
 export interface RibbitSettings {
     api?: unknown;
     editorId?: string;
     plugins?: Array<{ new(settings: { name: string; wiki: Ribbit }): RibbitPlugin; name: string }>;
+    currentTheme?: string;
+    themes?: RibbitTheme[];
+    themesPath?: string;
 }
 
 /**
@@ -53,10 +59,15 @@ export class Ribbit {
     state: string | null;
     changed: boolean;
     enabledPlugins: Record<string, RibbitPlugin>;
+    theme: RibbitTheme;
+    themes: ThemeManager;
+    converter: HopDown;
+    themesPath: string;
 
     constructor(settings: RibbitSettings) {
         this.api = settings.api || null;
         this.element = document.getElementById(settings.editorId || 'ribbit')!;
+        this.themesPath = settings.themesPath || './themes';
         this.states = {
             VIEW: 'view',
         };
@@ -66,6 +77,29 @@ export class Ribbit {
         this.changed = false;
         this.enabledPlugins = {};
 
+        this.themes = new ThemeManager(defaultTheme, this.themesPath, (theme) => {
+            this.theme = theme;
+            this.converter = theme.tags
+                ? new HopDown({ tags: theme.tags })
+                : new HopDown();
+            this.cachedHTML = null;
+            if (this.getState() === this.states.VIEW) {
+                this.state = null;
+                this.view();
+            }
+        });
+
+        (settings.themes || []).forEach(theme => {
+            this.themes.add(theme);
+        });
+
+        const activeName = settings.currentTheme || defaultTheme.name;
+        this.themes.set(activeName);
+        this.theme = this.themes.current();
+        this.converter = this.theme.tags
+            ? new HopDown({ tags: this.theme.tags })
+            : new HopDown();
+
         (settings.plugins || []).forEach(plugin => {
             this.enabledPlugins[plugin.name] = new plugin({
                 name: plugin.name,
@@ -99,7 +133,7 @@ export class Ribbit {
     }
 
     markdownToHTML(md: string): string {
-        return hopdown.toHTML(md);
+        return this.converter.toHTML(md);
     }
 
     getHTML(): string {

src/ts/theme-manager.ts

@@ -0,0 +1,114 @@
+/*
+ * theme-manager.ts — manages theme registration and activation for a Ribbit instance.
+ */
+
+import type { RibbitTheme } from './types';
+import { HopDown } from './hopdown';
+
+export class ThemeManager {
+    private registered: Map<string, RibbitTheme>;
+    private disabled: Set<string>;
+    private active: RibbitTheme;
+    private themeLink: HTMLLinkElement | null;
+    private themesPath: string;
+    private onSwitch: (theme: RibbitTheme) => void;
+
+    constructor(initial: RibbitTheme, themesPath: string, onSwitch: (theme: RibbitTheme) => void) {
+        this.registered = new Map();
+        this.disabled = new Set();
+        this.themeLink = null;
+        this.themesPath = themesPath;
+        this.onSwitch = onSwitch;
+        this.active = initial;
+        this.add(initial);
+    }
+
+    /**
+     * Register a theme. Themes must be added before they can be enabled.
+     */
+    add(theme: RibbitTheme): void {
+        this.registered.set(theme.name, theme);
+    }
+
+    /**
+     * Unregister a theme by name. Cannot remove the active theme.
+     */
+    remove(name: string): void {
+        if (this.active.name === name) {
+            throw new Error(`Cannot remove the active theme "${name}".`);
+        }
+        this.registered.delete(name);
+    }
+
+    /**
+     * Return the names of all registered and enabled themes.
+     */
+    list(): string[] {
+        return Array.from(this.registered.keys()).filter(name => !this.disabled.has(name));
+    }
+
+    /**
+     * Get a registered theme by name, or undefined if not found.
+     */
+    get(name: string): RibbitTheme | undefined {
+        return this.registered.get(name);
+    }
+
+    /**
+     * Return the currently active theme.
+     */
+    current(): RibbitTheme {
+        return this.active;
+    }
+
+    /**
+     * Switch to a registered theme by name. The theme must be
+     * registered and enabled. Loads the theme's CSS and notifies
+     * the editor to rebuild its converter.
+     */
+    set(name: string): void {
+        const theme = this.registered.get(name);
+        if (!theme) {
+            throw new Error(`Theme "${name}" is not registered. Call add() first.`);
+        }
+        if (this.disabled.has(name)) {
+            throw new Error(`Theme "${name}" is disabled. Call enable() first.`);
+        }
+        this.active = theme;
+        this.loadCSS(name);
+        this.onSwitch(theme);
+    }
+
+    /**
+     * Mark a theme as available for selection via set().
+     * Themes are enabled by default when added.
+     */
+    enable(name: string): void {
+        if (!this.registered.has(name)) {
+            throw new Error(`Theme "${name}" is not registered. Call add() first.`);
+        }
+        this.disabled.delete(name);
+    }
+
+    /**
+     * Mark a theme as unavailable for selection via set().
+     * Does not affect the current theme if it is already active.
+     */
+    disable(name: string): void {
+        if (!this.registered.has(name)) {
+            throw new Error(`Theme "${name}" is not registered.`);
+        }
+        this.disabled.add(name);
+    }
+
+    private loadCSS(name: string): void {
+        if (this.themeLink) {
+            this.themeLink.remove();
+        }
+        const link = document.createElement('link');
+        link.rel = 'stylesheet';
+        link.href = `${this.themesPath}/${name}/theme.css`;
+        document.head.appendChild(link);
+        this.themeLink = link;
+    }
+}

src/ts/types.ts

@@ -54,3 +54,13 @@ export interface InlineTagDef {
     /** Process inner content for nested markdown? Default true. False for code spans. */
     recursive?: boolean;
 }
+
+export interface RibbitThemeFeatures {
+    sourceMode?: boolean;
+}
+
+export interface RibbitTheme {
+    name: string;
+    tags?: Record<string, Tag>;
+    features?: RibbitThemeFeatures;
+}