feat(web): add Tiptap WYSIWYG KnowledgeEditor component (#500)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/web/src/components/knowledge/KnowledgeEditor.tsx

@@ -0,0 +1,437 @@
+"use client";
+
+import { useCallback } from "react";
+import type { ReactElement } from "react";
+import { useEditor, EditorContent } from "@tiptap/react";
+import StarterKit from "@tiptap/starter-kit";
+import Link from "@tiptap/extension-link";
+import { Table } from "@tiptap/extension-table";
+import { TableRow } from "@tiptap/extension-table-row";
+import { TableCell } from "@tiptap/extension-table-cell";
+import { TableHeader } from "@tiptap/extension-table-header";
+import CodeBlockLowlight from "@tiptap/extension-code-block-lowlight";
+import Placeholder from "@tiptap/extension-placeholder";
+import { common, createLowlight } from "lowlight";
+import type { Editor } from "@tiptap/react";
+
+import "./KnowledgeEditor.css";
+
+const lowlight = createLowlight(common);
+
+export interface KnowledgeEditorProps {
+  /** HTML content for the editor */
+  content: string;
+  /** Called when editor content changes (provides HTML) */
+  onChange: (html: string) => void;
+  /** Placeholder text when editor is empty */
+  placeholder?: string;
+  /** Whether the editor is editable */
+  editable?: boolean;
+}
+
+/** Toolbar button helper */
+function ToolbarButton({
+  onClick,
+  active,
+  disabled,
+  title,
+  children,
+}: {
+  onClick: () => void;
+  active?: boolean;
+  disabled?: boolean;
+  title: string;
+  children: React.ReactNode;
+}): ReactElement {
+  return (
+    <button
+      type="button"
+      onClick={onClick}
+      disabled={disabled}
+      title={title}
+      style={{
+        display: "inline-flex",
+        alignItems: "center",
+        justifyContent: "center",
+        width: 32,
+        height: 32,
+        borderRadius: "var(--r-sm)",
+        border: "none",
+        background: active ? "var(--primary)" : "transparent",
+        color: active ? "#fff" : "var(--text-2)",
+        cursor: disabled ? "default" : "pointer",
+        opacity: disabled ? 0.4 : 1,
+        fontSize: "0.82rem",
+        fontWeight: 600,
+        transition: "all 0.12s ease",
+        lineHeight: 1,
+      }}
+    >
+      {children}
+    </button>
+  );
+}
+
+/** Separator between toolbar groups */
+function ToolbarSep(): ReactElement {
+  return (
+    <div
+      style={{
+        width: 1,
+        height: 20,
+        background: "var(--border)",
+        margin: "0 4px",
+        flexShrink: 0,
+      }}
+    />
+  );
+}
+
+/** Link insertion handler — prompts for URL */
+function toggleLink(editor: Editor): void {
+  if (editor.isActive("link")) {
+    editor.chain().focus().unsetLink().run();
+    return;
+  }
+  const url = window.prompt("Enter URL:");
+  if (url) {
+    editor.chain().focus().extendMarkRange("link").setLink({ href: url }).run();
+  }
+}
+
+/* SVG icon components for toolbar */
+function BulletListIcon(): ReactElement {
+  return (
+    <svg width="16" height="16" viewBox="0 0 16 16" fill="currentColor">
+      <circle cx="3" cy="4" r="1.5" />
+      <rect x="6" y="3" width="8" height="2" rx="0.5" />
+      <circle cx="3" cy="8" r="1.5" />
+      <rect x="6" y="7" width="8" height="2" rx="0.5" />
+      <circle cx="3" cy="12" r="1.5" />
+      <rect x="6" y="11" width="8" height="2" rx="0.5" />
+    </svg>
+  );
+}
+
+function OrderedListIcon(): ReactElement {
+  return (
+    <svg width="16" height="16" viewBox="0 0 16 16" fill="currentColor">
+      <text x="1" y="5.5" fontSize="5" fontWeight="bold">
+        1
+      </text>
+      <rect x="6" y="3" width="8" height="2" rx="0.5" />
+      <text x="1" y="9.5" fontSize="5" fontWeight="bold">
+        2
+      </text>
+      <rect x="6" y="7" width="8" height="2" rx="0.5" />
+      <text x="1" y="13.5" fontSize="5" fontWeight="bold">
+        3
+      </text>
+      <rect x="6" y="11" width="8" height="2" rx="0.5" />
+    </svg>
+  );
+}
+
+function QuoteIcon(): ReactElement {
+  return (
+    <svg width="16" height="16" viewBox="0 0 16 16" fill="currentColor">
+      <path d="M3 3h2l-1 4h2v6H2V7l1-4zm7 0h2l-1 4h2v6H9V7l1-4z" />
+    </svg>
+  );
+}
+
+function CodeBlockIcon(): ReactElement {
+  return (
+    <svg
+      width="16"
+      height="16"
+      viewBox="0 0 16 16"
+      fill="none"
+      stroke="currentColor"
+      strokeWidth="1.5"
+    >
+      <polyline points="5,3 1,8 5,13" />
+      <polyline points="11,3 15,8 11,13" />
+      <line x1="9" y1="2" x2="7" y2="14" />
+    </svg>
+  );
+}
+
+function LinkIcon(): ReactElement {
+  return (
+    <svg
+      width="16"
+      height="16"
+      viewBox="0 0 16 16"
+      fill="none"
+      stroke="currentColor"
+      strokeWidth="1.5"
+    >
+      <path d="M6.5 9.5l3-3" />
+      <path d="M9 6l1.5-1.5a2.12 2.12 0 013 3L12 9" />
+      <path d="M7 10l-1.5 1.5a2.12 2.12 0 01-3-3L4 7" />
+    </svg>
+  );
+}
+
+function TableIcon(): ReactElement {
+  return (
+    <svg
+      width="16"
+      height="16"
+      viewBox="0 0 16 16"
+      fill="none"
+      stroke="currentColor"
+      strokeWidth="1.2"
+    >
+      <rect x="1" y="2" width="14" height="12" rx="1" />
+      <line x1="1" y1="6" x2="15" y2="6" />
+      <line x1="1" y1="10" x2="15" y2="10" />
+      <line x1="6" y1="2" x2="6" y2="14" />
+      <line x1="11" y1="2" x2="11" y2="14" />
+    </svg>
+  );
+}
+
+/** Editor toolbar component */
+function EditorToolbar({ editor }: { editor: Editor }): ReactElement {
+  return (
+    <div
+      style={{
+        display: "flex",
+        alignItems: "center",
+        flexWrap: "wrap",
+        gap: 2,
+        padding: "6px 8px",
+        borderBottom: "1px solid var(--border)",
+        background: "var(--surface-2)",
+        borderRadius: "var(--r-lg) var(--r-lg) 0 0",
+      }}
+    >
+      {/* Headings */}
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleHeading({ level: 1 }).run();
+        }}
+        active={editor.isActive("heading", { level: 1 })}
+        title="Heading 1"
+      >
+        H1
+      </ToolbarButton>
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleHeading({ level: 2 }).run();
+        }}
+        active={editor.isActive("heading", { level: 2 })}
+        title="Heading 2"
+      >
+        H2
+      </ToolbarButton>
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleHeading({ level: 3 }).run();
+        }}
+        active={editor.isActive("heading", { level: 3 })}
+        title="Heading 3"
+      >
+        H3
+      </ToolbarButton>
+
+      <ToolbarSep />
+
+      {/* Text formatting */}
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleBold().run();
+        }}
+        active={editor.isActive("bold")}
+        title="Bold (Ctrl+B)"
+      >
+        B
+      </ToolbarButton>
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleItalic().run();
+        }}
+        active={editor.isActive("italic")}
+        title="Italic (Ctrl+I)"
+      >
+        <span style={{ fontStyle: "italic" }}>I</span>
+      </ToolbarButton>
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleStrike().run();
+        }}
+        active={editor.isActive("strike")}
+        title="Strikethrough"
+      >
+        <span style={{ textDecoration: "line-through" }}>S</span>
+      </ToolbarButton>
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleCode().run();
+        }}
+        active={editor.isActive("code")}
+        title="Inline Code"
+      >
+        {"<>"}
+      </ToolbarButton>
+
+      <ToolbarSep />
+
+      {/* Lists */}
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleBulletList().run();
+        }}
+        active={editor.isActive("bulletList")}
+        title="Bullet List"
+      >
+        <BulletListIcon />
+      </ToolbarButton>
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleOrderedList().run();
+        }}
+        active={editor.isActive("orderedList")}
+        title="Ordered List"
+      >
+        <OrderedListIcon />
+      </ToolbarButton>
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleBlockquote().run();
+        }}
+        active={editor.isActive("blockquote")}
+        title="Blockquote"
+      >
+        <QuoteIcon />
+      </ToolbarButton>
+
+      <ToolbarSep />
+
+      {/* Code block */}
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().toggleCodeBlock().run();
+        }}
+        active={editor.isActive("codeBlock")}
+        title="Code Block"
+      >
+        <CodeBlockIcon />
+      </ToolbarButton>
+
+      {/* Link */}
+      <ToolbarButton
+        onClick={(): void => {
+          toggleLink(editor);
+        }}
+        active={editor.isActive("link")}
+        title="Insert Link"
+      >
+        <LinkIcon />
+      </ToolbarButton>
+
+      {/* Table */}
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().insertTable({ rows: 3, cols: 3, withHeaderRow: true }).run();
+        }}
+        disabled={editor.isActive("table")}
+        title="Insert Table"
+      >
+        <TableIcon />
+      </ToolbarButton>
+
+      <ToolbarSep />
+
+      {/* Horizontal rule */}
+      <ToolbarButton
+        onClick={(): void => {
+          editor.chain().focus().setHorizontalRule().run();
+        }}
+        title="Horizontal Rule"
+      >
+        —
+      </ToolbarButton>
+    </div>
+  );
+}
+
+export function KnowledgeEditor({
+  content,
+  onChange,
+  placeholder = "Start writing...",
+  editable = true,
+}: KnowledgeEditorProps): ReactElement {
+  const handleUpdate = useCallback(
+    ({ editor: e }: { editor: Editor }) => {
+      onChange(e.getHTML());
+    },
+    [onChange]
+  );
+
+  const editor = useEditor({
+    extensions: [
+      StarterKit.configure({
+        codeBlock: false,
+      }),
+      Link.configure({
+        openOnClick: false,
+        HTMLAttributes: {
+          rel: "noopener noreferrer",
+          class: "knowledge-editor-link",
+        },
+      }),
+      Table.configure({
+        resizable: true,
+      }),
+      TableRow,
+      TableCell,
+      TableHeader,
+      CodeBlockLowlight.configure({
+        lowlight,
+      }),
+      Placeholder.configure({
+        placeholder,
+      }),
+    ],
+    content,
+    editable,
+    onUpdate: handleUpdate,
+  });
+
+  // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition -- useEditor returns null during SSR/init
+  if (!editor) {
+    return (
+      <div
+        style={{
+          minHeight: 300,
+          background: "var(--surface)",
+          border: "1px solid var(--border)",
+          borderRadius: "var(--r-lg)",
+          display: "flex",
+          alignItems: "center",
+          justifyContent: "center",
+        }}
+      >
+        <span style={{ color: "var(--muted)", fontSize: "0.85rem" }}>Loading editor...</span>
+      </div>
+    );
+  }
+
+  return (
+    <div
+      className="knowledge-editor"
+      style={{
+        border: "1px solid var(--border)",
+        borderRadius: "var(--r-lg)",
+        overflow: "hidden",
+        background: "var(--surface)",
+      }}
+    >
+      {editable && <EditorToolbar editor={editor} />}
+      <EditorContent editor={editor} className="knowledge-editor-content" />
+    </div>
+  );
+}