Editor: Extract Config to New Theme as a third Config action

src/app/components/SpecEditor.tsx

@@ -28,6 +28,7 @@ import { openModal } from '../modals/ModalCoordinator';
 import {
   installSpecConfigActions,
   runExtractConfig,
+  runExtractConfigToTheme,
   runMergeChartTheme,
 } from '../services/spec-config-actions';
 import { useAppStore } from '../stores/AppStore';
@@ -160,6 +161,11 @@ const CONFIG_ACTIONS = [
     label: 'Extract config from spec',
     detail: 'Remove the config block and copy it to the clipboard',
   },
+  {
+    value: 'extract-theme',
+    label: 'Extract config to new theme',
+    detail: 'Save the config block as a custom chart theme and select it',
+  },
 ] as const;
 
 type ConfigActionId = (typeof CONFIG_ACTIONS)[number]['value'];
@@ -194,7 +200,8 @@ function EditorToolbar({
     const editor = editorRef.current;
     if (!editor) return;
     if (action === 'merge') runMergeChartTheme(editor);
-    else void runExtractConfig(editor);
+    else if (action === 'extract') void runExtractConfig(editor);
+    else runExtractConfigToTheme(editor);
   };
 
   const handleRevert = async () => {

src/app/services/spec-config-actions.ts

@@ -10,6 +10,9 @@
  *   it to the clipboard — for cleaning baked-in styling out of a pasted spec.
  *   The clipboard write happens *before* the edit, so a clipboard failure
  *   never destroys the only copy.
+ * - **Extract config to new theme** removes the block and saves it as a custom
+ *   chart theme instead, selecting it — the one-step "this pasted spec's
+ *   styling should be a reusable theme" path.
  *
  * Both replace the document via `executeEdits`, so ⌘Z restores the previous
  * text. Both no-op (with a toast naming the reason) on invalid JSON; Monaco's
@@ -26,10 +29,16 @@
 import * as monaco from 'monaco-editor/esm/vs/editor/edcore.main';
 import { formatJson } from '@core/json-format';
 import { extractConfigFromSpec, isJsonObject, mergeConfigIntoSpec } from '@core/spec-config';
-import { CHART_THEME_OPTIONS, chartConfigForSelection } from '@core/vega-themes';
+import {
+  CHART_THEME_OPTIONS,
+  chartConfigForSelection,
+  customThemeSelection,
+} from '@core/vega-themes';
 import { copyText } from '../infrastructure/file-transfer';
 import { useAppStore } from '../stores/AppStore';
+import { useCustomThemeStore } from '../stores/CustomThemeStore';
 import { notify } from '../stores/NotificationStore';
+import { selectActiveSnippet, useSnippetStore } from '../stores/SnippetStore';
 
 /** Parse the model's JSON, or toast (and return null) when it isn't a JSON object. */
 function parseSpecObject(model: monaco.editor.ITextModel): Record<string, unknown> | null {
@@ -140,7 +149,47 @@ export async function runExtractConfig(editor: monaco.editor.IStandaloneCodeEdit
 }
 
 /**
- * Register both actions on the editor (context menu + F1 palette — the expert
+ * Turn the draft's `config` block into a saved custom theme: create the theme
+ * (named after the snippet, auto-suffixed if taken), remove the block from the
+ * spec, and select the new theme as the active chart theme — so the styling
+ * keeps applying to this chart, now from the injected side of the boundary.
+ * (Not pixel-identical when another theme was active: that theme's
+ * non-overlapping keys stop applying once the new theme replaces it.)
+ */
+export function runExtractConfigToTheme(editor: monaco.editor.IStandaloneCodeEditor): void {
+  const model = editor.getModel();
+  if (!model) return;
+  const spec = parseSpecObject(model);
+  if (!spec) return;
+
+  const { spec: rest, config } = extractConfigFromSpec(spec);
+  if (config === null) {
+    notify({
+      kind: 'info',
+      title: 'No config to extract',
+      message: 'This spec has no config block.',
+    });
+    return;
+  }
+
+  const snippet = selectActiveSnippet(useSnippetStore.getState());
+  const theme = useCustomThemeStore
+    .getState()
+    .createTheme(snippet ? `${snippet.name} theme` : 'Extracted theme', config);
+  useAppStore.getState().setChartTheme(customThemeSelection(theme.id));
+
+  replaceDocument(editor, model, 'extract-config-to-theme', rest);
+  notify({
+    kind: 'success',
+    title: 'Theme created',
+    message:
+      `The config block became the custom theme “${theme.name}”, now selected as the ` +
+      'chart theme. Rename or refine it via Edit themes…; undo the spec edit with ⌘/Ctrl+Z.',
+  });
+}
+
+/**
+ * Register the config actions on the editor (context menu + F1 palette — the expert
  * accelerators; the toolbar Config menu is the discoverable home). Returns a
  * disposable that detaches them (dispose on editor unmount, like the
  * format-on-paste hook).
@@ -166,10 +215,20 @@ export function installSpecConfigActions(
     run: () => runExtractConfig(editor),
   });
 
+  const extractToTheme = editor.addAction({
+    id: 'astrolabe.extract-config-to-theme',
+    label: 'Extract Config to New Theme',
+    contextMenuGroupId: 'astrolabe',
+    contextMenuOrder: 3,
+    precondition: '!editorReadonly',
+    run: () => runExtractConfigToTheme(editor),
+  });
+
   return {
     dispose() {
       merge.dispose();
       extract.dispose();
+      extractToTheme.dispose();
     },
   };
 }