feat(editor): highlight duplicate matches in mermaid editor

Co-authored-by: dwelle <5153846+dwelle@users.noreply.github.com>

packages/element/src/collision.ts

@@ -465,7 +465,12 @@ export const intersectElementWithLineSegment = (
     case "line":
     case "freedraw":
     case "arrow":
-      return intersectLinearOrFreeDrawWithLineSegment(element, line, onlyFirst);
+      return intersectLinearOrFreeDrawWithLineSegment(
+        element,
+        line,
+        elementsMap,
+        onlyFirst,
+      );
   }
 };
 
@@ -532,11 +537,15 @@ const lineIntersections = (
 const intersectLinearOrFreeDrawWithLineSegment = (
   element: ExcalidrawLinearElement | ExcalidrawFreeDrawElement,
   segment: LineSegment<GlobalPoint>,
+  elementsMap: ElementsMap,
   onlyFirst = false,
 ): GlobalPoint[] => {
   // NOTE: This is the only one which return the decomposed elements
   // rotated! This is due to taking advantage of roughjs definitions.
-  const [lines, curves] = deconstructLinearOrFreeDrawElement(element);
+  const [lines, curves] = deconstructLinearOrFreeDrawElement(
+    element,
+    elementsMap,
+  );
   const intersections: GlobalPoint[] = [];
 
   for (const l of lines) {

packages/element/src/distance.ts

@@ -48,7 +48,7 @@ export const distanceToElement = (
     case "line":
     case "arrow":
     case "freedraw":
-      return distanceToLinearOrFreeDraElement(element, p);
+      return distanceToLinearOrFreeDraElement(element, elementsMap, p);
   }
 };
 
@@ -133,9 +133,13 @@ const distanceToEllipseElement = (
 
 const distanceToLinearOrFreeDraElement = (
   element: ExcalidrawLinearElement | ExcalidrawFreeDrawElement,
+  elementsMap: ElementsMap,
   p: GlobalPoint,
 ) => {
-  const [lines, curves] = deconstructLinearOrFreeDrawElement(element);
+  const [lines, curves] = deconstructLinearOrFreeDrawElement(
+    element,
+    elementsMap,
+  );
   return Math.min(
     ...lines.map((s) => distanceToLineSegment(p, s)),
     ...curves.map((a) => curvePointDistance(a, p)),

packages/element/src/linearElementEditor.ts

@@ -476,16 +476,22 @@ export class LinearElementEditor {
       });
     }
 
-    invariant(
-      lastClickedPoint > -1 &&
-        selectedPointsIndices.includes(lastClickedPoint) &&
-        element.points[lastClickedPoint],
-      `There must be a valid lastClickedPoint in order to drag it. selectedPointsIndices(${JSON.stringify(
-        selectedPointsIndices,
-      )}) points(0..${
-        element.points.length - 1
-      }) lastClickedPoint(${lastClickedPoint})`,
-    );
+    if (
+      lastClickedPoint < 0 ||
+      !selectedPointsIndices.includes(lastClickedPoint) ||
+      !element.points[lastClickedPoint]
+    ) {
+      console.error(
+        `There must be a valid lastClickedPoint in order to drag it. selectedPointsIndices(${JSON.stringify(
+          selectedPointsIndices,
+        )}) points(0..${
+          element.points.length - 1
+        }) lastClickedPoint(${lastClickedPoint})`,
+      );
+
+      // Fall back to the actual last point as a last resort.
+      lastClickedPoint = element.points.length - 1;
+    }
 
     // point that's being dragged (out of all selected points)
     const draggingPoint = element.points[lastClickedPoint];
@@ -794,6 +800,7 @@ export class LinearElementEditor {
           element.points[index + 1],
           index,
           appState.zoom,
+          elementsMap,
         )
       ) {
         midpoints.push(null);
@@ -803,6 +810,7 @@ export class LinearElementEditor {
       const segmentMidPoint = LinearElementEditor.getSegmentMidPoint(
         element,
         index + 1,
+        elementsMap,
       );
       midpoints.push(segmentMidPoint);
       index++;
@@ -890,6 +898,7 @@ export class LinearElementEditor {
     endPoint: P,
     index: number,
     zoom: Zoom,
+    elementsMap: ElementsMap,
   ) {
     if (isElbowArrow(element)) {
       if (index >= 0 && index < element.points.length) {
@@ -904,7 +913,10 @@ export class LinearElementEditor {
 
     let distance = pointDistance(startPoint, endPoint);
     if (element.points.length > 2 && element.roundness) {
-      const [lines, curves] = deconstructLinearOrFreeDrawElement(element);
+      const [lines, curves] = deconstructLinearOrFreeDrawElement(
+        element,
+        elementsMap,
+      );
 
       invariant(
         lines.length === 0 && curves.length > 0,
@@ -924,6 +936,7 @@ export class LinearElementEditor {
   static getSegmentMidPoint(
     element: NonDeleted<ExcalidrawLinearElement>,
     index: number,
+    elementsMap: ElementsMap,
   ): GlobalPoint {
     if (isElbowArrow(element)) {
       invariant(
@@ -936,7 +949,10 @@ export class LinearElementEditor {
       return pointFrom<GlobalPoint>(element.x + p[0], element.y + p[1]);
     }
 
-    const [lines, curves] = deconstructLinearOrFreeDrawElement(element);
+    const [lines, curves] = deconstructLinearOrFreeDrawElement(
+      element,
+      elementsMap,
+    );
 
     invariant(
       (lines.length === 0 && curves.length > 0) ||
@@ -1851,6 +1867,7 @@ export class LinearElementEditor {
       const midSegmentMidpoint = LinearElementEditor.getSegmentMidPoint(
         element,
         index + 1,
+        elementsMap,
       );
 
       x = midSegmentMidpoint[0] - boundTextElement.width / 2;
@@ -2400,7 +2417,7 @@ const pointDraggingUpdates = (
     ? nextArrow.points[0]
     : endBindable
     ? updateBoundPoint(
-        element,
+        nextArrow,
         "endBinding",
         nextArrow.endBinding,
         endBindable,
@@ -2431,7 +2448,7 @@ const pointDraggingUpdates = (
       ? endLocalPoint
       : startBindable
       ? updateBoundPoint(
-          element,
+          nextArrow,
           "startBinding",
           nextArrow.startBinding,
           startBindable,

packages/element/src/shape.ts

@@ -57,8 +57,8 @@ import { headingForPointIsHorizontal } from "./heading";
 
 import { canChangeRoundness } from "./comparisons";
 import {
+  elementCenterPoint,
   getArrowheadPoints,
-  getCenterForBounds,
   getDiamondPoints,
   getElementAbsoluteCoords,
 } from "./bounds";
@@ -583,7 +583,11 @@ const getArrowheadShapes = (
 
 export const generateLinearCollisionShape = (
   element: ExcalidrawLinearElement | ExcalidrawFreeDrawElement,
-) => {
+  elementsMap: ElementsMap,
+): {
+  op: string;
+  data: number[];
+}[] => {
   const generator = new RoughGenerator();
   const options: Options = {
     seed: element.seed,
@@ -592,20 +596,7 @@ export const generateLinearCollisionShape = (
     roughness: 0,
     preserveVertices: true,
   };
-  const center = getCenterForBounds(
-    // Need a non-rotated center point
-    element.points.reduce(
-      (acc, point) => {
-        return [
-          Math.min(element.x + point[0], acc[0]),
-          Math.min(element.y + point[1], acc[1]),
-          Math.max(element.x + point[0], acc[2]),
-          Math.max(element.y + point[1], acc[3]),
-        ];
-      },
-      [Infinity, Infinity, -Infinity, -Infinity],
-    ),
-  );
+  const center = elementCenterPoint(element, elementsMap);
 
   switch (element.type) {
     case "line":

packages/element/src/textElement.ts

@@ -347,6 +347,7 @@ export const getContainerCenter = (
     midSegmentMidpoint = LinearElementEditor.getSegmentMidPoint(
       container,
       index + 1,
+      elementsMap,
     );
   }
   return { x: midSegmentMidpoint[0], y: midSegmentMidpoint[1] };

packages/element/src/utils.ts

@@ -124,6 +124,7 @@ const setElementShapesCacheEntry = <T extends ExcalidrawElement>(
  */
 export function deconstructLinearOrFreeDrawElement(
   element: ExcalidrawLinearElement | ExcalidrawFreeDrawElement,
+  elementsMap: ElementsMap,
 ): [LineSegment<GlobalPoint>[], Curve<GlobalPoint>[]] {
   const cachedShape = getElementShapesCacheEntry(element, 0);
 
@@ -131,10 +132,7 @@ export function deconstructLinearOrFreeDrawElement(
     return cachedShape;
   }
 
-  const ops = generateLinearCollisionShape(element) as {
-    op: string;
-    data: number[];
-  }[];
+  const ops = generateLinearCollisionShape(element, elementsMap);
   const lines = [];
   const curves = [];
 

packages/excalidraw/components/App.tsx

@@ -6995,27 +6995,23 @@ class App extends React.Component<AppProps, AppState> {
           },
           { informMutation: false, isDragging: false },
         );
+        const newLastIdx = multiElement.points.length - 1;
         this.setState({
           selectedLinearElement: {
             ...selectedLinearElement,
-            selectedPointsIndices:
-              selectedLinearElement.selectedPointsIndices?.includes(
-                multiElement.points.length,
-              )
-                ? [
-                    ...selectedLinearElement.selectedPointsIndices.filter(
-                      (idx) =>
-                        idx !== multiElement.points.length &&
-                        idx !== multiElement.points.length - 1,
+            selectedPointsIndices: selectedLinearElement.selectedPointsIndices
+              ? [
+                  ...new Set(
+                    selectedLinearElement.selectedPointsIndices.map((idx) =>
+                      Math.min(idx, newLastIdx),
                     ),
-                    multiElement.points.length - 1,
-                  ]
-                : selectedLinearElement.selectedPointsIndices,
-            lastCommittedPoint:
-              multiElement.points[multiElement.points.length - 1],
+                  ),
+                ]
+              : selectedLinearElement.selectedPointsIndices,
+            lastCommittedPoint: multiElement.points[newLastIdx],
             initialState: {
               ...selectedLinearElement.initialState,
-              lastClickedPoint: multiElement.points.length - 1,
+              lastClickedPoint: newLastIdx,
             },
           },
         });

packages/excalidraw/components/TTDDialog/Chat/Chat.scss

@@ -3,7 +3,25 @@
 $verticalBreakpoint: 861px;
 
 .excalidraw {
+  --ttd-mermaid-token-keyword: #0000ff;
+  --ttd-mermaid-token-string: #a31515;
+  --ttd-mermaid-token-comment: #008000;
+  --ttd-mermaid-token-number: #098658;
+  --ttd-mermaid-token-operator: #1e1e1e;
+  --ttd-mermaid-token-punctuation: #1e1e1e;
+  --ttd-mermaid-token-variable-name: #001080;
+  --ttd-mermaid-token-bracket: #af00db;
+
   &.theme--dark {
+    --ttd-mermaid-token-keyword: #569cd6;
+    --ttd-mermaid-token-string: #ce9178;
+    --ttd-mermaid-token-comment: #6a9955;
+    --ttd-mermaid-token-number: #b5cea8;
+    --ttd-mermaid-token-operator: #d4d4d4;
+    --ttd-mermaid-token-punctuation: #d4d4d4;
+    --ttd-mermaid-token-variable-name: #9cdcfe;
+    --ttd-mermaid-token-bracket: #ffd700;
+
     .chat-message {
       &--assistant {
         .chat-message__content {
@@ -194,7 +212,7 @@ $verticalBreakpoint: 861px;
       align-items: flex-start;
 
       .chat-message__content {
-        background: var(--color-surface-low);
+        background: #f7f7f7;
         color: var(--color-on-surface);
         border-radius: var(--border-radius-md);
         min-width: 6rem;
@@ -292,6 +310,51 @@ $verticalBreakpoint: 861px;
       word-wrap: break-word;
     }
 
+    &__text--error {
+      color: inherit;
+    }
+
+    &__text--mermaid {
+      overflow-x: auto;
+      font-weight: 400;
+    }
+
+    &__token {
+      white-space: inherit;
+    }
+
+    &__token--keyword {
+      color: var(--ttd-mermaid-token-keyword);
+    }
+
+    &__token--string {
+      color: var(--ttd-mermaid-token-string);
+    }
+
+    &__token--comment {
+      color: var(--ttd-mermaid-token-comment);
+    }
+
+    &__token--number {
+      color: var(--ttd-mermaid-token-number);
+    }
+
+    &__token--operator {
+      color: var(--ttd-mermaid-token-operator);
+    }
+
+    &__token--punctuation {
+      color: var(--ttd-mermaid-token-punctuation);
+    }
+
+    &__token--variableName {
+      color: var(--ttd-mermaid-token-variable-name);
+    }
+
+    &__token--bracket {
+      color: var(--ttd-mermaid-token-bracket);
+    }
+
     &__cursor {
       display: inline-block;
       margin-left: 2px;
@@ -332,11 +395,13 @@ $verticalBreakpoint: 861px;
     &__error {
       color: var(--color-danger);
       font-weight: 500;
-      white-space: pre-wrap;
-      word-wrap: break-word;
       display: flex;
       flex-direction: column;
       gap: 0.5rem;
+
+      .chat-message__text--mermaid {
+        color: var(--color-on-surface);
+      }
     }
 
     &__error_message {

packages/excalidraw/components/TTDDialog/Chat/ChatMessage.tsx

@@ -5,8 +5,49 @@ import { t } from "../../../i18n";
 import { FilledButton } from "../../FilledButton";
 import { TrashIcon, codeIcon, stackPushIcon, RetryIcon } from "../../icons";
 
+import { tokenizeMermaid } from "../mermaid-highlighting";
+
 import type { TChat, TTTDDialog } from "../types";
 
+const isMermaidMessage = (message: TChat.ChatMessage) =>
+  message.contentFormat === "mermaid";
+
+const renderMessageContent = (
+  message: TChat.ChatMessage,
+  className: string,
+) => {
+  const content = message.content ?? "";
+
+  console.log("@", message);
+
+  if (!isMermaidMessage(message)) {
+    return (
+      <div className={className}>
+        {content}
+        {message.isGenerating && (
+          <span className="chat-message__cursor">▋</span>
+        )}
+      </div>
+    );
+  }
+
+  return (
+    <div className={clsx(className, "chat-message__text--mermaid")}>
+      {tokenizeMermaid(content).map((token, index) => (
+        <span
+          key={`${index}-${token.type ?? "text"}-${token.value}`}
+          className={clsx("chat-message__token", {
+            [`chat-message__token--${token.type}`]: token.type,
+          })}
+        >
+          {token.value}
+        </span>
+      ))}
+      {message.isGenerating && <span className="chat-message__cursor">▋</span>}
+    </div>
+  );
+};
+
 export const ChatMessage: React.FC<{
   message: TChat.ChatMessage;
   onMermaidTabClick?: (message: TChat.ChatMessage) => void;
@@ -122,7 +163,14 @@ export const ChatMessage: React.FC<{
         <div className="chat-message__body">
           {message.error ? (
             <>
-              <div className="chat-message__error">{message.content}</div>
+              <div className="chat-message__error">
+                {renderMessageContent(
+                  message,
+                  clsx("chat-message__text", {
+                    "chat-message__text--error": !isMermaidMessage(message),
+                  }),
+                )}
+              </div>
               {message.errorType !== "parse" && (
                 <div className="chat-message__error_message">
                   Error: {message.error || t("chat.errors.generationFailed")}
@@ -132,7 +180,7 @@ export const ChatMessage: React.FC<{
                 <div className="chat-message__error_message">
                   <p>{t("chat.errors.invalidDiagram")}</p>
                   <div className="chat-message__error-actions">
-                    {onMermaidTabClick && (
+                    {onMermaidTabClick && isMermaidMessage(message) && (
                       <button
                         className="chat-message__error-link"
                         onClick={() => onMermaidTabClick(message)}
@@ -156,18 +204,13 @@ export const ChatMessage: React.FC<{
               )}
             </>
           ) : (
-            <div className="chat-message__text">
-              {message.content}
-              {message.isGenerating && (
-                <span className="chat-message__cursor">▋</span>
-              )}
-            </div>
+            renderMessageContent(message, "chat-message__text")
           )}
         </div>
       </div>
       {message.type === "assistant" && !message.isGenerating && (
         <div className="chat-message__actions">
-          {!message.error && onInsertMessage && (
+          {!message.error && onInsertMessage && isMermaidMessage(message) && (
             <button
               className="chat-message__action"
               onClick={() => onInsertMessage(message)}
@@ -178,7 +221,7 @@ export const ChatMessage: React.FC<{
               {stackPushIcon}
             </button>
           )}
-          {onMermaidTabClick && message.content && (
+          {onMermaidTabClick && isMermaidMessage(message) && message.content && (
             <button
               className="chat-message__action"
               onClick={() => onMermaidTabClick(message)}

packages/excalidraw/components/TTDDialog/Chat/TTDChatPanel.tsx

@@ -25,6 +25,7 @@ export const TTDChatPanel = ({
   onGenerate,
   isGenerating,
   generatedResponse,
+  generatedResponseFormat,
   isMenuOpen,
   onMenuToggle,
   onMenuClose,
@@ -50,6 +51,7 @@ export const TTDChatPanel = ({
   onGenerate: TTTDDialog.OnGenerate;
   isGenerating: boolean;
   generatedResponse: string | null | undefined;
+  generatedResponseFormat?: TChat.ChatMessage["contentFormat"];
 
   isMenuOpen: boolean;
   onMenuToggle: () => void;
@@ -89,7 +91,7 @@ export const TTDChatPanel = ({
       });
     }
 
-    if (generatedResponse) {
+    if (generatedResponse && generatedResponseFormat === "mermaid") {
       actions.push({
         action: onViewAsMermaid,
         label: t("chat.viewAsMermaid"),

packages/excalidraw/components/TTDDialog/Chat/useChatAgent.ts

@@ -25,6 +25,7 @@ export const useChatAgent = () => {
         {
           type: "assistant",
           content: "",
+          contentFormat: "mermaid",
           isGenerating: true,
         },
       ]),

packages/excalidraw/components/TTDDialog/CodeMirrorEditor.tsx

@@ -1,13 +1,21 @@
 import { useEffect, useRef } from "react";
 import {
   Decoration,
+  type DecorationSet,
   EditorView,
+  ViewPlugin,
+  type ViewUpdate,
   keymap,
   lineNumbers,
   placeholder as cmPlaceholder,
   drawSelection,
 } from "@codemirror/view";
-import { Compartment, EditorState, type Extension } from "@codemirror/state";
+import {
+  Compartment,
+  EditorState,
+  type Extension,
+  type Range,
+} from "@codemirror/state";
 import {
   defaultKeymap,
   history,
@@ -40,6 +48,13 @@ const darkTheme = EditorView.theme(
     },
     ".cm-content": { caretColor: "#fff" },
     ".cm-cursor": { borderLeftColor: "#fff" },
+    ".cm-selectionBackground": {
+      backgroundColor: "rgba(86, 156, 214, 0.3)",
+    },
+    "&.cm-focused > .cm-scroller > .cm-selectionLayer .cm-selectionBackground":
+      {
+        backgroundColor: "rgba(86, 156, 214, 0.42)",
+      },
     ".cm-gutters": {
       backgroundColor: "#1e1e1e",
       color: "#858585",
@@ -48,6 +63,10 @@ const darkTheme = EditorView.theme(
     ".cm-activeLineGutter": { backgroundColor: "#2a2a2a" },
     ".cm-activeLine": { backgroundColor: "#2a2a2a" },
     ".cm-errorLine": { backgroundColor: "rgba(255, 0, 0, 0.15)" },
+    ".cm-selectedWordMatch": {
+      backgroundColor: "rgba(255, 209, 102, 0.22)",
+      borderRadius: "2px",
+    },
   },
   { dark: true },
 );
@@ -80,6 +99,10 @@ const lightTheme = EditorView.theme({
   ".cm-activeLineGutter": { backgroundColor: "#e8e8e8" },
   ".cm-activeLine": { backgroundColor: "#e8e8e8" },
   ".cm-errorLine": { backgroundColor: "rgba(255, 0, 0, 0.1)" },
+  ".cm-selectedWordMatch": {
+    backgroundColor: "rgba(255, 209, 102, 0.35)",
+    borderRadius: "2px",
+  },
 });
 
 const lightHighlight = HighlightStyle.define([
@@ -96,6 +119,79 @@ const lightHighlight = HighlightStyle.define([
 // ---- Error line decoration ----
 
 const errorLineDeco = Decoration.line({ class: "cm-errorLine" });
+const selectedWordMatchDeco = Decoration.mark({
+  class: "cm-selectedWordMatch",
+});
+
+const getSelectedWordMatchText = (state: EditorState) => {
+  const mainSelection = state.selection.main;
+  if (state.selection.ranges.length !== 1 || mainSelection.empty) {
+    return null;
+  }
+
+  const selectedWord = state.wordAt(mainSelection.from);
+  if (
+    !selectedWord ||
+    selectedWord.from !== mainSelection.from ||
+    selectedWord.to !== mainSelection.to
+  ) {
+    return null;
+  }
+
+  return state.sliceDoc(mainSelection.from, mainSelection.to);
+};
+
+const getSelectedWordMatchDecorations = (view: EditorView): DecorationSet => {
+  const selectedWord = getSelectedWordMatchText(view.state);
+  if (!selectedWord) {
+    return Decoration.none;
+  }
+
+  const selection = view.state.selection.main;
+  const ranges: Range<Decoration>[] = [];
+  const doc = view.state.doc.toString();
+  let searchFrom = 0;
+
+  while (searchFrom <= doc.length - selectedWord.length) {
+    const matchFrom = doc.indexOf(selectedWord, searchFrom);
+    if (matchFrom === -1) {
+      break;
+    }
+
+    const matchTo = matchFrom + selectedWord.length;
+    const matchWord = view.state.wordAt(matchFrom);
+    if (
+      matchWord?.from === matchFrom &&
+      matchWord.to === matchTo &&
+      (matchFrom !== selection.from || matchTo !== selection.to)
+    ) {
+      ranges.push(selectedWordMatchDeco.range(matchFrom, matchTo));
+    }
+
+    searchFrom = matchTo;
+  }
+
+  return ranges.length ? Decoration.set(ranges) : Decoration.none;
+};
+
+const selectedWordMatchExtension = ViewPlugin.fromClass(
+  class {
+    decorations: DecorationSet;
+
+    constructor(view: EditorView) {
+      this.decorations = getSelectedWordMatchDecorations(view);
+    }
+
+    update(update: ViewUpdate) {
+      if (update.docChanged || update.selectionSet) {
+        this.decorations = getSelectedWordMatchDecorations(update.view);
+      }
+    }
+  },
+  {
+    decorations: (value) => value.decorations,
+  },
+);
 
 const getErrorLineExtension = (
   errorLine: number | null | undefined,
@@ -172,6 +268,7 @@ const CodeMirrorEditor = ({
           errorLineCompartmentRef.current.of([]),
           mermaidLite(),
           drawSelection({ drawRangeCursor: true }),
+          selectedWordMatchExtension,
           ...(placeholder ? [cmPlaceholder(placeholder)] : []),
         ],
       }),

packages/excalidraw/components/TTDDialog/TextToDiagram.tsx

@@ -80,7 +80,10 @@ const TextToDiagramContent = ({
   } = useChatManagement({ persistenceAdapter });
 
   const onViewAsMermaid = () => {
-    if (typeof lastAssistantMessage?.content === "string") {
+    if (
+      lastAssistantMessage?.contentFormat === "mermaid" &&
+      typeof lastAssistantMessage.content === "string"
+    ) {
       saveMermaidDataToStorage(lastAssistantMessage.content);
       setAppState({
         openDialog: { name: "ttd", tab: "mermaid" },
@@ -206,6 +209,7 @@ const TextToDiagramContent = ({
         onGenerate={onGenerate}
         isGenerating={lastAssistantMessage?.isGenerating ?? false}
         generatedResponse={lastAssistantMessage?.content}
+        generatedResponseFormat={lastAssistantMessage?.contentFormat}
         isMenuOpen={isMenuOpen}
         onMenuToggle={handleMenuToggle}
         onMenuClose={handleMenuClose}

packages/excalidraw/components/TTDDialog/hooks/useTextGeneration.ts

@@ -88,6 +88,7 @@ export const useTextGeneration = ({
         updateAssistantContent(prev, {
           isGenerating: true,
           content: "",
+          contentFormat: "mermaid",
           error: undefined,
           errorType: undefined,
           errorDetails: undefined,

packages/excalidraw/components/TTDDialog/mermaid-highlighting.test.ts

@@ -0,0 +1,40 @@
+import {
+  getMermaidHighlightToken,
+  tokenizeMermaid,
+} from "./mermaid-highlighting";
+
+describe("mermaid highlighting", () => {
+  it("tokenizes mermaid syntax with shared token types", () => {
+    const tokens = tokenizeMermaid('flowchart LR\nA["Hello"] --> B');
+
+    expect(tokens).toEqual([
+      { type: "keyword", value: "flowchart" },
+      { type: null, value: " " },
+      { type: "keyword", value: "LR" },
+      { type: null, value: "\n" },
+      { type: "variableName", value: "A" },
+      { type: "bracket", value: "[" },
+      { type: "string", value: '"Hello"' },
+      { type: "bracket", value: "]" },
+      { type: null, value: " " },
+      { type: "operator", value: "-->" },
+      { type: null, value: " " },
+      { type: "variableName", value: "B" },
+    ]);
+  });
+
+  it("limits comment tokens to a single line", () => {
+    const tokens = tokenizeMermaid("%% comment\nflowchart TD");
+
+    expect(tokens[0]).toEqual({ type: "comment", value: "%% comment" });
+    expect(tokens[1]).toEqual({ type: null, value: "\n" });
+    expect(tokens[2]).toEqual({ type: "keyword", value: "flowchart" });
+  });
+
+  it("falls back to plain text for unsupported characters", () => {
+    expect(getMermaidHighlightToken("@node")).toEqual({
+      type: null,
+      value: "@",
+    });
+  });
+});

packages/excalidraw/components/TTDDialog/mermaid-highlighting.ts

@@ -0,0 +1,79 @@
+export type MermaidHighlightTokenType =
+  | "bracket"
+  | "comment"
+  | "keyword"
+  | "number"
+  | "operator"
+  | "punctuation"
+  | "string"
+  | "variableName";
+
+export type MermaidHighlightToken = {
+  type: MermaidHighlightTokenType | null;
+  value: string;
+};
+
+const DIAGRAM_TYPE_PATTERN =
+  /^(flowchart|graph|sequenceDiagram|classDiagram|stateDiagram|erDiagram|gantt|pie|mindmap|journey|gitGraph|timeline|quadrantChart|sankey|xychart)\b/i;
+const DIRECTION_PATTERN = /^(TB|TD|BT|RL|LR)\b/;
+const KEYWORD_PATTERN =
+  /^(subgraph|end|participant|actor|loop|alt|else|opt|par|critical|break|rect|note|over|activate|deactivate|title|section|class|style|linkStyle|classDef|click)\b/i;
+
+const MERMAID_TOKEN_RULES: ReadonlyArray<{
+  pattern: RegExp;
+  type: MermaidHighlightTokenType | null;
+}> = [
+  { pattern: /^%%[^\n]*/, type: "comment" },
+  { pattern: /^"(?:[^"\\]|\\.)*"/, type: "string" },
+  { pattern: DIAGRAM_TYPE_PATTERN, type: "keyword" },
+  { pattern: DIRECTION_PATTERN, type: "keyword" },
+  { pattern: KEYWORD_PATTERN, type: "keyword" },
+  { pattern: /^[-.=<>|ox]+>/, type: "operator" },
+  { pattern: /^<[-.=<>|ox]+/, type: "operator" },
+  { pattern: /^(--+|\.\.+|==+)/, type: "operator" },
+  { pattern: /^[[\](){}|<>]/, type: "bracket" },
+  { pattern: /^[A-Za-z_][A-Za-z0-9_]*/, type: "variableName" },
+  { pattern: /^\d+(\.\d+)?/, type: "number" },
+  { pattern: /^[,:;]/, type: "punctuation" },
+  { pattern: /^\s+/, type: null },
+];
+
+export const getMermaidHighlightToken = (
+  input: string,
+): MermaidHighlightToken | null => {
+  if (!input) {
+    return null;
+  }
+
+  for (const rule of MERMAID_TOKEN_RULES) {
+    const match = input.match(rule.pattern);
+    if (match) {
+      return {
+        type: rule.type,
+        value: match[0],
+      };
+    }
+  }
+
+  return {
+    type: null,
+    value: input[0],
+  };
+};
+
+export const tokenizeMermaid = (input: string): MermaidHighlightToken[] => {
+  const tokens: MermaidHighlightToken[] = [];
+  let remaining = input;
+
+  while (remaining) {
+    const token = getMermaidHighlightToken(remaining);
+    if (!token) {
+      break;
+    }
+
+    tokens.push(token);
+    remaining = remaining.slice(token.value.length);
+  }
+
+  return tokens;
+};

packages/excalidraw/components/TTDDialog/mermaid-lang-lite.ts

@@ -1,79 +1,17 @@
 import { StreamLanguage } from "@codemirror/language";
 
+import { getMermaidHighlightToken } from "./mermaid-highlighting";
+
 const mermaidStreamParser = StreamLanguage.define({
   token(stream) {
-    // Comments: %%...
-    if (stream.match(/^%%.*$/)) {
-      return "comment";
-    }
-
-    // Strings
-    if (stream.match(/^"(?:[^"\\]|\\.)*"/)) {
-      return "string";
-    }
-
-    // Diagram type keywords (at start of line or after whitespace)
-    if (
-      stream.match(
-        /^(flowchart|graph|sequenceDiagram|classDiagram|stateDiagram|erDiagram|gantt|pie|mindmap|journey|gitGraph|timeline|quadrantChart|sankey|xychart)\b/i,
-      )
-    ) {
-      return "keyword";
-    }
-
-    // Direction keywords
-    if (stream.match(/^(TB|TD|BT|RL|LR)\b/)) {
-      return "keyword";
-    }
-
-    // Keywords
-    if (
-      stream.match(
-        /^(subgraph|end|participant|actor|loop|alt|else|opt|par|critical|break|rect|note|over|activate|deactivate|title|section|class|style|linkStyle|classDef|click)\b/i,
-      )
-    ) {
-      return "keyword";
-    }
-
-    // Arrows: -->, ---, -.->, ===>, etc.
-    if (stream.match(/^[-.=<>|ox]+>/)) {
-      return "operator";
-    }
-    if (stream.match(/^<[-.=<>|ox]+/)) {
-      return "operator";
-    }
-    if (stream.match(/^--+|\.\.+|==+/)) {
-      return "operator";
-    }
-
-    // Labels in brackets/parens: [text], (text), {text}, ((text)), etc.
-    if (stream.match(/^[[\](){}|<>]/)) {
-      return "bracket";
-    }
-
-    // Node IDs (alphanumeric)
-    if (stream.match(/^[A-Za-z_][A-Za-z0-9_]*/)) {
-      return "variableName";
-    }
-
-    // Numbers
-    if (stream.match(/^\d+(\.\d+)?/)) {
-      return "number";
-    }
-
-    // Punctuation
-    if (stream.match(/^[,:;]/)) {
-      return "punctuation";
-    }
-
-    // Skip whitespace
-    if (stream.eatSpace()) {
+    const token = getMermaidHighlightToken(stream.string.slice(stream.pos));
+    if (!token) {
+      stream.skipToEnd();
       return null;
     }
 
-    // Skip any other character
-    stream.next();
-    return null;
+    stream.pos += token.value.length;
+    return token.type;
   },
 });
 

packages/excalidraw/components/TTDDialog/types.ts

@@ -18,6 +18,8 @@ export type MermaidData = {
   files: BinaryFiles | null;
 };
 
+export type ChatMessageContentFormat = "text" | "mermaid";
+
 export interface RateLimits {
   rateLimit: number;
   rateLimitRemaining: number;
@@ -33,6 +35,7 @@ export namespace TChat {
     errorType?: "parse" | "network" | "other";
     lastAttemptAt?: number;
     type: "user" | "assistant" | "warning";
+    contentFormat?: ChatMessageContentFormat;
     warningType?: /* daily rate limit */
     "messageLimitExceeded" | /* general 429 */ "rateLimitExceeded";
     content?: string;

packages/excalidraw/components/TTDDialog/useTTDChatStorage.ts

@@ -7,6 +7,17 @@ import { chatHistoryAtom } from "./TTDContext";
 
 import type { SavedChat, SavedChats, TTDPersistenceAdapter } from "./types";
 
+const normalizePersistedChat = (chat: SavedChat): SavedChat => ({
+  ...chat,
+  messages: chat.messages.map((message) => ({
+    ...message,
+    // Legacy TTD chats predate explicit content format metadata.
+    contentFormat:
+      message.contentFormat ??
+      (message.type === "assistant" ? "mermaid" : undefined),
+  })),
+});
+
 interface UseTTDChatStorageProps {
   persistenceAdapter: TTDPersistenceAdapter;
 }
@@ -56,7 +67,7 @@ export const useTTDChatStorage = ({
     setIsLoading(true);
     try {
       const chats = await persistenceAdapter.loadChats();
-      setSavedChats(chats);
+      setSavedChats(chats.map(normalizePersistedChat));
       setChatsLoaded(true);
     } catch (error) {
       console.warn("Failed to load chats:", error);

packages/excalidraw/components/TTDDialog/utils/chat.test.ts

@@ -117,6 +117,28 @@ describe("chat utils", () => {
       expect(result.messages[0].errorType).toBe("network");
     });
 
+    it("should update content format when provided", () => {
+      const chatHistory: TChat.ChatHistory = {
+        id: "chat-1",
+        currentPrompt: "",
+        messages: [
+          {
+            id: "1",
+            type: "assistant",
+            content: "graph TD",
+            timestamp: new Date("2024-01-01"),
+            contentFormat: "text",
+          },
+        ],
+      };
+
+      const result = updateAssistantContent(chatHistory, {
+        contentFormat: "mermaid",
+      });
+
+      expect(result.messages[0].contentFormat).toBe("mermaid");
+    });
+
     it("should return unchanged chatHistory if no assistant message exists", () => {
       const chatHistory: TChat.ChatHistory = {
         id: "chat-1",
@@ -357,6 +379,7 @@ describe("chat utils", () => {
         {
           type: "assistant",
           content: "Message",
+          contentFormat: "mermaid",
           isGenerating: true,
           error: "Error text",
           errorType: "parse",
@@ -364,6 +387,7 @@ describe("chat utils", () => {
       ]);
 
       expect(result.messages[0].isGenerating).toBe(true);
+      expect(result.messages[0].contentFormat).toBe("mermaid");
       expect(result.messages[0].error).toBe("Error text");
       expect(result.messages[0].errorType).toBe("parse");
     });

packages/excalidraw/data/restore.ts

@@ -251,7 +251,9 @@ const repairBinding = <T extends ExcalidrawArrowElement>(
       };
     }
 
-    console.error(`could not repair binding for element`);
+    console.error(
+      `Could not repair binding for element "${boundElement?.id}" out of (${elementsMap?.size}) elements`,
+    );
   } catch (error) {
     console.error("Error repairing binding:", error);
   }

packages/excalidraw/index.tsx

@@ -382,6 +382,8 @@ export { DiagramToCodePlugin } from "./components/DiagramToCodePlugin/DiagramToC
 export { getDataURL } from "./data/blob";
 export { isElementLink } from "@excalidraw/element";
 
+export { Fonts } from "./fonts/Fonts";
+
 export { setCustomTextMetricsProvider } from "@excalidraw/element";
 
 export { CommandPalette } from "./components/CommandPalette/CommandPalette";

packages/excalidraw/renderer/interactiveScene.ts

@@ -1156,6 +1156,7 @@ const renderLinearPointHandles = (
           points[idx],
           idx,
           appState.zoom,
+          elementsMap,
         )
       ) {
         renderSingleLinearPoint(

packages/excalidraw/tests/__snapshots__/history.test.tsx.snap

@@ -224,7 +224,7 @@ exports[`history > multiplayer undo/redo > conflicts in arrows and their bindabl
   "strokeWidth": 2,
   "type": "arrow",
   "updated": 1,
-  "version": 28,
+  "version": 22,
   "width": "94.00000",
   "x": 0,
   "y": 0,
@@ -350,8 +350,9 @@ exports[`history > multiplayer undo/redo > conflicts in arrows and their bindabl
               ],
               "mode": "orbit",
             },
-            "version": 27,
+            "version": 21,
             "width": "88.00000",
+            "y": "7.20923",
           },
           "inserted": {
             "endBinding": {
@@ -381,8 +382,9 @@ exports[`history > multiplayer undo/redo > conflicts in arrows and their bindabl
               ],
               "mode": "orbit",
             },
-            "version": 24,
+            "version": 20,
             "width": "88.00000",
+            "y": "0.01000",
           },
         },
       },
@@ -437,7 +439,7 @@ exports[`history > multiplayer undo/redo > conflicts in arrows and their bindabl
               ],
             ],
             "startBinding": null,
-            "version": 28,
+            "version": 22,
             "width": "94.00000",
             "x": 0,
             "y": 0,
@@ -462,7 +464,7 @@ exports[`history > multiplayer undo/redo > conflicts in arrows and their bindabl
               ],
               "mode": "orbit",
             },
-            "version": 27,
+            "version": 21,
             "width": "88.00000",
             "x": 6,
             "y": "7.20923",
@@ -16254,7 +16256,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
   "strokeWidth": 2,
   "type": "arrow",
   "updated": 1,
-  "version": 11,
+  "version": 10,
   "width": "88.00000",
   "x": 6,
   "y": "0.01000",
@@ -16307,7 +16309,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
               ],
               "mode": "orbit",
             },
-            "version": 11,
+            "version": 10,
           },
           "inserted": {
             "endBinding": {
@@ -16327,7 +16329,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
               ],
               "mode": "orbit",
             },
-            "version": 9,
+            "version": 8,
           },
         },
       },
@@ -16636,7 +16638,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
             "fillStyle": "solid",
             "frameId": null,
             "groupIds": [],
-            "height": "0.00120",
+            "height": 0,
             "index": "a3",
             "isDeleted": false,
             "link": null,
@@ -16649,7 +16651,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
               ],
               [
                 "88.00000",
-                "0.00120",
+                0,
               ],
             ],
             "roughness": 1,
@@ -16669,14 +16671,14 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
             "strokeStyle": "solid",
             "strokeWidth": 2,
             "type": "arrow",
-            "version": 8,
+            "version": 7,
             "width": "88.00000",
             "x": 6,
-            "y": "0.00880",
+            "y": "0.01000",
           },
           "inserted": {
             "isDeleted": true,
-            "version": 7,
+            "version": 6,
           },
         },
       },
@@ -17002,7 +17004,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
   "strokeWidth": 2,
   "type": "arrow",
   "updated": 1,
-  "version": 11,
+  "version": 10,
   "width": "88.00000",
   "x": 6,
   "y": "0.01000",
@@ -17307,14 +17309,14 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
             "strokeStyle": "solid",
             "strokeWidth": 2,
             "type": "arrow",
-            "version": 11,
+            "version": 10,
             "width": "88.00000",
             "x": 6,
             "y": "0.01000",
           },
           "inserted": {
             "isDeleted": true,
-            "version": 9,
+            "version": 8,
           },
         },
       },
@@ -17648,7 +17650,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
   "strokeWidth": 2,
   "type": "arrow",
   "updated": 1,
-  "version": 11,
+  "version": 10,
   "width": "88.00000",
   "x": 6,
   "y": "0.01000",
@@ -17953,14 +17955,14 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
             "strokeStyle": "solid",
             "strokeWidth": 2,
             "type": "arrow",
-            "version": 11,
+            "version": 10,
             "width": "88.00000",
             "x": 6,
             "y": "0.01000",
           },
           "inserted": {
             "isDeleted": true,
-            "version": 9,
+            "version": 8,
           },
         },
       },
@@ -18292,7 +18294,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
   "strokeWidth": 2,
   "type": "arrow",
   "updated": 1,
-  "version": 11,
+  "version": 10,
   "width": "88.00000",
   "x": 6,
   "y": "0.01000",
@@ -18361,7 +18363,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
               ],
               "mode": "orbit",
             },
-            "version": 11,
+            "version": 10,
           },
           "inserted": {
             "endBinding": {
@@ -18373,7 +18375,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
               "mode": "orbit",
             },
             "startBinding": null,
-            "version": 9,
+            "version": 8,
           },
         },
         "id2": {
@@ -18650,7 +18652,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
             "fillStyle": "solid",
             "frameId": null,
             "groupIds": [],
-            "height": "0.00120",
+            "height": 0,
             "index": "a3",
             "isDeleted": false,
             "link": null,
@@ -18663,7 +18665,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
               ],
               [
                 "88.00000",
-                "0.00120",
+                0,
               ],
             ],
             "roughness": 1,
@@ -18683,14 +18685,14 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
             "strokeStyle": "solid",
             "strokeWidth": 2,
             "type": "arrow",
-            "version": 8,
+            "version": 7,
             "width": "88.00000",
             "x": 6,
-            "y": "0.00880",
+            "y": "0.01000",
           },
           "inserted": {
             "isDeleted": true,
-            "version": 7,
+            "version": 6,
           },
         },
       },
@@ -19044,7 +19046,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
   "strokeWidth": 2,
   "type": "arrow",
   "updated": 1,
-  "version": 12,
+  "version": 11,
   "width": "88.00000",
   "x": 6,
   "y": "0.01000",
@@ -19124,12 +19126,12 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
               ],
               "mode": "orbit",
             },
-            "version": 12,
+            "version": 11,
           },
           "inserted": {
             "endBinding": null,
             "startBinding": null,
-            "version": 10,
+            "version": 9,
           },
         },
       },
@@ -19398,7 +19400,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
             "fillStyle": "solid",
             "frameId": null,
             "groupIds": [],
-            "height": "0.00120",
+            "height": 0,
             "index": "a3",
             "isDeleted": false,
             "link": null,
@@ -19411,7 +19413,7 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
               ],
               [
                 "88.00000",
-                "0.00120",
+                0,
               ],
             ],
             "roughness": 1,
@@ -19431,14 +19433,14 @@ exports[`history > singleplayer undo/redo > should support bidirectional binding
             "strokeStyle": "solid",
             "strokeWidth": 2,
             "type": "arrow",
-            "version": 8,
+            "version": 7,
             "width": "88.00000",
             "x": 6,
-            "y": "0.00880",
+            "y": "0.01000",
           },
           "inserted": {
             "isDeleted": true,
-            "version": 7,
+            "version": 6,
           },
         },
       },

yarn.lock

@@ -1531,10 +1531,10 @@
   resolved "https://registry.yarnpkg.com/@excalidraw/markdown-to-text/-/markdown-to-text-0.1.2.tgz#1703705e7da608cf478f17bfe96fb295f55a23eb"
   integrity sha512-1nDXBNAojfi3oSFwJswKREkFm5wrSjqay81QlyRv2pkITG/XYB5v+oChENVBQLcxQwX4IUATWvXM5BcaNhPiIg==
 
-"@excalidraw/mermaid-to-excalidraw@2.1.0":
-  version "2.1.0"
-  resolved "https://registry.yarnpkg.com/@excalidraw/mermaid-to-excalidraw/-/mermaid-to-excalidraw-2.1.0.tgz#a5b9cf87c3185558cda7f9687d87b9937f452358"
-  integrity sha512-RMd+c2b7WzzUjhERMpKwp8PhF2/XlHDjr/zK+Gxfp8K9sVlafPYJ5OEa/GkN6edi2rBUXRfW+41WdO6L56b6Kw==
+"@excalidraw/mermaid-to-excalidraw@2.1.1":
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/@excalidraw/mermaid-to-excalidraw/-/mermaid-to-excalidraw-2.1.1.tgz#659c934a607dd2cf57f2a69282588ee2b0722959"
+  integrity sha512-jU+frqcxazsY+t5yOBf2mgrQy+WUrbrzA36if3SQB/Vwaf2qOJjnWxucNafgZZk/3+9xGmRotUeOviSOJG+wYA==
   dependencies:
     "@excalidraw/markdown-to-text" "0.1.2"
     "@mermaid-js/parser" "^0.6.3"