feat(editor): add floating formatting toolbar

src/App.tsx

@@ -1,12 +1,15 @@
 import { useState } from "react";
+import type { Editor as TiptapEditor } from "@tiptap/react";
 import { Sidebar } from "./components/Sidebar";
 import { Dock } from "./components/Dock";
 import { Icon } from "./components/Icon";
 import { Editor } from "./editor/Editor";
+import { FloatingToolbar } from "./editor/FloatingToolbar";
 import { useBook } from "./store/useBook";
 
 function App() {
   const [dock, setDock] = useState(true);
+  const [editor, setEditor] = useState<TiptapEditor | null>(null);
   const title = useBook((s) => s.book.metadata.title);
   const author = useBook((s) => s.book.metadata.author);
   const chapters = useBook((s) => s.book.chapters);
@@ -49,8 +52,10 @@ function App() {
               chapterId={chapter.id}
               content={chapter.content}
               onChange={(content) => setChapterContent(chapter.id, content)}
+              onReady={setEditor}
             />
           </article>
+          <FloatingToolbar editor={editor} />
         </main>
         {dock && <Dock />}
       </div>

src/editor/Editor.tsx

@@ -1,4 +1,5 @@
-import { EditorContent, useEditor } from "@tiptap/react";
+import { useEffect } from "react";
+import { EditorContent, useEditor, type Editor as TiptapEditor } from "@tiptap/react";
 import type { JSONContent } from "@tiptap/core";
 import { editorExtensions } from "./extensions";
 
@@ -6,9 +7,10 @@ interface EditorProps {
   chapterId: string;
   content: JSONContent;
   onChange: (content: JSONContent) => void;
+  onReady: (editor: TiptapEditor | null) => void;
 }
 
-export function Editor({ chapterId, content, onChange }: EditorProps) {
+export function Editor({ chapterId, content, onChange, onReady }: EditorProps) {
   const editor = useEditor(
     {
       extensions: editorExtensions,
@@ -20,5 +22,9 @@ export function Editor({ chapterId, content, onChange }: EditorProps) {
     [chapterId]
   );
 
+  useEffect(() => {
+    onReady(editor);
+  }, [editor, onReady]);
+
   return <EditorContent editor={editor} className="editor-host" />;
 }

src/editor/FloatingToolbar.tsx

@@ -0,0 +1,59 @@
+import { useRef, type ReactNode } from "react";
+import type { Editor } from "@tiptap/react";
+import { Icon } from "../components/Icon";
+
+function readImage(file: File): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const reader = new FileReader();
+    reader.onload = () => resolve(reader.result as string);
+    reader.onerror = reject;
+    reader.readAsDataURL(file);
+  });
+}
+
+export function FloatingToolbar({ editor }: { editor: Editor | null }) {
+  const fileRef = useRef<HTMLInputElement>(null);
+  if (!editor) return null;
+
+  const insertImage = async (file: File) => {
+    const src = await readImage(file);
+    editor.chain().focus().insertContent({ type: "figure", attrs: { src, placement: "full-width" } }).run();
+  };
+
+  const tool = (active: boolean, onClick: () => void, title: string, content: ReactNode) => (
+    <button
+      className="tool"
+      data-on={active}
+      title={title}
+      onMouseDown={(e) => e.preventDefault()}
+      onClick={onClick}
+    >
+      {content}
+    </button>
+  );
+
+  return (
+    <div className="editor-toolbar">
+      {tool(editor.isActive("bold"), () => editor.chain().focus().toggleBold().run(), "Bold", <b>B</b>)}
+      {tool(editor.isActive("italic"), () => editor.chain().focus().toggleItalic().run(), "Italic", <i>I</i>)}
+      <span className="tool-sep" />
+      {tool(editor.isActive("heading", { level: 2 }), () => editor.chain().focus().toggleHeading({ level: 2 }).run(), "Heading", <Icon d="M5 5v14M5 12h8M13 5v14" />)}
+      {tool(editor.isActive("blockquote"), () => editor.chain().focus().toggleBlockquote().run(), "Quote", <Icon d="M7 8h4v4a4 4 0 0 1-4 4M14 8h4v4a4 4 0 0 1-4 4" />)}
+      {tool(editor.isActive("bulletList"), () => editor.chain().focus().toggleBulletList().run(), "Bulleted list", <Icon d="M8 6h12M8 12h12M8 18h12M3.5 6h.01M3.5 12h.01M3.5 18h.01" />)}
+      <span className="tool-sep" />
+      {tool(false, () => editor.chain().focus().setHorizontalRule().run(), "Scene break", <Icon d="M5 12h5M14 12h5" />)}
+      {tool(false, () => fileRef.current?.click(), "Insert image", <Icon d="M4 5h16v14H4zM4 16l4.5-4.5 3 3L16 10l4 4" />)}
+      <input
+        ref={fileRef}
+        type="file"
+        accept="image/*"
+        hidden
+        onChange={(e) => {
+          const file = e.target.files?.[0];
+          if (file) insertImage(file);
+          e.currentTarget.value = "";
+        }}
+      />
+    </div>
+  );
+}