refactor: packages/

1 files changed, 715 insertions, 0 deletions

diff --git a/packages/excalidraw/element/flowchart.ts b/packages/excalidraw/element/flowchart.ts
new file mode 100644
index 0000000..09f006d
--- /dev/null
+++ b/packages/excalidraw/element/flowchart.ts
@@ -0,0 +1,715 @@
+import {
+  HEADING_DOWN,
+  HEADING_LEFT,
+  HEADING_RIGHT,
+  HEADING_UP,
+  compareHeading,
+  headingForPointFromElement,
+  type Heading,
+} from "./heading";
+import { bindLinearElement } from "./binding";
+import { LinearElementEditor } from "./linearElementEditor";
+import { newArrowElement, newElement } from "./newElement";
+import {
+  type ElementsMap,
+  type ExcalidrawBindableElement,
+  type ExcalidrawElement,
+  type ExcalidrawFlowchartNodeElement,
+  type NonDeletedSceneElementsMap,
+  type Ordered,
+  type OrderedExcalidrawElement,
+} from "./types";
+import { KEYS } from "../keys";
+import type { AppState, PendingExcalidrawElements } from "../types";
+import { mutateElement } from "./mutateElement";
+import { elementOverlapsWithFrame, elementsAreInFrameBounds } from "../frame";
+import {
+  isBindableElement,
+  isElbowArrow,
+  isFrameElement,
+  isFlowchartNodeElement,
+} from "./typeChecks";
+import { invariant, toBrandedType } from "../utils";
+import { pointFrom, type LocalPoint } from "@excalidraw/math";
+import { aabbForElement } from "../shapes";
+import { updateElbowArrowPoints } from "./elbowArrow";
+
+type LinkDirection = "up" | "right" | "down" | "left";
+
+const VERTICAL_OFFSET = 100;
+const HORIZONTAL_OFFSET = 100;
+
+export const getLinkDirectionFromKey = (key: string): LinkDirection => {
+  switch (key) {
+    case KEYS.ARROW_UP:
+      return "up";
+    case KEYS.ARROW_DOWN:
+      return "down";
+    case KEYS.ARROW_RIGHT:
+      return "right";
+    case KEYS.ARROW_LEFT:
+      return "left";
+    default:
+      return "right";
+  }
+};
+
+const getNodeRelatives = (
+  type: "predecessors" | "successors",
+  node: ExcalidrawBindableElement,
+  elementsMap: ElementsMap,
+  direction: LinkDirection,
+) => {
+  const items = [...elementsMap.values()].reduce(
+    (acc: { relative: ExcalidrawBindableElement; heading: Heading }[], el) => {
+      let oppositeBinding;
+      if (
+        isElbowArrow(el) &&
+        // we want check existence of the opposite binding, in the direction
+        // we're interested in
+        (oppositeBinding =
+          el[type === "predecessors" ? "startBinding" : "endBinding"]) &&
+        // similarly, we need to filter only arrows bound to target node
+        el[type === "predecessors" ? "endBinding" : "startBinding"]
+          ?.elementId === node.id
+      ) {
+        const relative = elementsMap.get(oppositeBinding.elementId);
+
+        if (!relative) {
+          return acc;
+        }
+
+        invariant(
+          isBindableElement(relative),
+          "not an ExcalidrawBindableElement",
+        );
+
+        const edgePoint = (
+          type === "predecessors" ? el.points[el.points.length - 1] : [0, 0]
+        ) as Readonly<LocalPoint>;
+
+        const heading = headingForPointFromElement(node, aabbForElement(node), [
+          edgePoint[0] + el.x,
+          edgePoint[1] + el.y,
+        ] as Readonly<LocalPoint>);
+
+        acc.push({
+          relative,
+          heading,
+        });
+      }
+      return acc;
+    },
+    [],
+  );
+
+  switch (direction) {
+    case "up":
+      return items
+        .filter((item) => compareHeading(item.heading, HEADING_UP))
+        .map((item) => item.relative);
+    case "down":
+      return items
+        .filter((item) => compareHeading(item.heading, HEADING_DOWN))
+        .map((item) => item.relative);
+    case "right":
+      return items
+        .filter((item) => compareHeading(item.heading, HEADING_RIGHT))
+        .map((item) => item.relative);
+    case "left":
+      return items
+        .filter((item) => compareHeading(item.heading, HEADING_LEFT))
+        .map((item) => item.relative);
+  }
+};
+
+const getSuccessors = (
+  node: ExcalidrawBindableElement,
+  elementsMap: ElementsMap,
+  direction: LinkDirection,
+) => {
+  return getNodeRelatives("successors", node, elementsMap, direction);
+};
+
+export const getPredecessors = (
+  node: ExcalidrawBindableElement,
+  elementsMap: ElementsMap,
+  direction: LinkDirection,
+) => {
+  return getNodeRelatives("predecessors", node, elementsMap, direction);
+};
+
+const getOffsets = (
+  element: ExcalidrawFlowchartNodeElement,
+  linkedNodes: ExcalidrawElement[],
+  direction: LinkDirection,
+) => {
+  const _HORIZONTAL_OFFSET = HORIZONTAL_OFFSET + element.width;
+
+  // check if vertical space or horizontal space is available first
+  if (direction === "up" || direction === "down") {
+    const _VERTICAL_OFFSET = VERTICAL_OFFSET + element.height;
+    // check vertical space
+    const minX = element.x;
+    const maxX = element.x + element.width;
+
+    // vertical space is available
+    if (
+      linkedNodes.every(
+        (linkedNode) =>
+          linkedNode.x + linkedNode.width < minX || linkedNode.x > maxX,
+      )
+    ) {
+      return {
+        x: 0,
+        y: _VERTICAL_OFFSET * (direction === "up" ? -1 : 1),
+      };
+    }
+  } else if (direction === "right" || direction === "left") {
+    const minY = element.y;
+    const maxY = element.y + element.height;
+
+    if (
+      linkedNodes.every(
+        (linkedNode) =>
+          linkedNode.y + linkedNode.height < minY || linkedNode.y > maxY,
+      )
+    ) {
+      return {
+        x:
+          (HORIZONTAL_OFFSET + element.width) * (direction === "left" ? -1 : 1),
+        y: 0,
+      };
+    }
+  }
+
+  if (direction === "up" || direction === "down") {
+    const _VERTICAL_OFFSET = VERTICAL_OFFSET + element.height;
+    const y = linkedNodes.length === 0 ? _VERTICAL_OFFSET : _VERTICAL_OFFSET;
+    const x =
+      linkedNodes.length === 0
+        ? 0
+        : (linkedNodes.length + 1) % 2 === 0
+        ? ((linkedNodes.length + 1) / 2) * _HORIZONTAL_OFFSET
+        : (linkedNodes.length / 2) * _HORIZONTAL_OFFSET * -1;
+
+    if (direction === "up") {
+      return {
+        x,
+        y: y * -1,
+      };
+    }
+
+    return {
+      x,
+      y,
+    };
+  }
+
+  const _VERTICAL_OFFSET = VERTICAL_OFFSET + element.height;
+  const x =
+    (linkedNodes.length === 0 ? HORIZONTAL_OFFSET : HORIZONTAL_OFFSET) +
+    element.width;
+  const y =
+    linkedNodes.length === 0
+      ? 0
+      : (linkedNodes.length + 1) % 2 === 0
+      ? ((linkedNodes.length + 1) / 2) * _VERTICAL_OFFSET
+      : (linkedNodes.length / 2) * _VERTICAL_OFFSET * -1;
+
+  if (direction === "left") {
+    return {
+      x: x * -1,
+      y,
+    };
+  }
+  return {
+    x,
+    y,
+  };
+};
+
+const addNewNode = (
+  element: ExcalidrawFlowchartNodeElement,
+  elementsMap: ElementsMap,
+  appState: AppState,
+  direction: LinkDirection,
+) => {
+  const successors = getSuccessors(element, elementsMap, direction);
+  const predeccessors = getPredecessors(element, elementsMap, direction);
+
+  const offsets = getOffsets(
+    element,
+    [...successors, ...predeccessors],
+    direction,
+  );
+
+  const nextNode = newElement({
+    type: element.type,
+    x: element.x + offsets.x,
+    y: element.y + offsets.y,
+    // TODO: extract this to a util
+    width: element.width,
+    height: element.height,
+    roundness: element.roundness,
+    roughness: element.roughness,
+    backgroundColor: element.backgroundColor,
+    strokeColor: element.strokeColor,
+    strokeWidth: element.strokeWidth,
+    opacity: element.opacity,
+    fillStyle: element.fillStyle,
+    strokeStyle: element.strokeStyle,
+  });
+
+  invariant(
+    isFlowchartNodeElement(nextNode),
+    "not an ExcalidrawFlowchartNodeElement",
+  );
+
+  const bindingArrow = createBindingArrow(
+    element,
+    nextNode,
+    elementsMap,
+    direction,
+    appState,
+  );
+
+  return {
+    nextNode,
+    bindingArrow,
+  };
+};
+
+export const addNewNodes = (
+  startNode: ExcalidrawFlowchartNodeElement,
+  elementsMap: ElementsMap,
+  appState: AppState,
+  direction: LinkDirection,
+  numberOfNodes: number,
+) => {
+  // always start from 0 and distribute evenly
+  const newNodes: ExcalidrawElement[] = [];
+
+  for (let i = 0; i < numberOfNodes; i++) {
+    let nextX: number;
+    let nextY: number;
+    if (direction === "left" || direction === "right") {
+      const totalHeight =
+        VERTICAL_OFFSET * (numberOfNodes - 1) +
+        numberOfNodes * startNode.height;
+
+      const startY = startNode.y + startNode.height / 2 - totalHeight / 2;
+
+      let offsetX = HORIZONTAL_OFFSET + startNode.width;
+      if (direction === "left") {
+        offsetX *= -1;
+      }
+      nextX = startNode.x + offsetX;
+      const offsetY = (VERTICAL_OFFSET + startNode.height) * i;
+      nextY = startY + offsetY;
+    } else {
+      const totalWidth =
+        HORIZONTAL_OFFSET * (numberOfNodes - 1) +
+        numberOfNodes * startNode.width;
+      const startX = startNode.x + startNode.width / 2 - totalWidth / 2;
+      let offsetY = VERTICAL_OFFSET + startNode.height;
+
+      if (direction === "up") {
+        offsetY *= -1;
+      }
+      nextY = startNode.y + offsetY;
+      const offsetX = (HORIZONTAL_OFFSET + startNode.width) * i;
+      nextX = startX + offsetX;
+    }
+
+    const nextNode = newElement({
+      type: startNode.type,
+      x: nextX,
+      y: nextY,
+      // TODO: extract this to a util
+      width: startNode.width,
+      height: startNode.height,
+      roundness: startNode.roundness,
+      roughness: startNode.roughness,
+      backgroundColor: startNode.backgroundColor,
+      strokeColor: startNode.strokeColor,
+      strokeWidth: startNode.strokeWidth,
+      opacity: startNode.opacity,
+      fillStyle: startNode.fillStyle,
+      strokeStyle: startNode.strokeStyle,
+    });
+
+    invariant(
+      isFlowchartNodeElement(nextNode),
+      "not an ExcalidrawFlowchartNodeElement",
+    );
+
+    const bindingArrow = createBindingArrow(
+      startNode,
+      nextNode,
+      elementsMap,
+      direction,
+      appState,
+    );
+
+    newNodes.push(nextNode);
+    newNodes.push(bindingArrow);
+  }
+
+  return newNodes;
+};
+
+const createBindingArrow = (
+  startBindingElement: ExcalidrawFlowchartNodeElement,
+  endBindingElement: ExcalidrawFlowchartNodeElement,
+  elementsMap: ElementsMap,
+  direction: LinkDirection,
+  appState: AppState,
+) => {
+  let startX: number;
+  let startY: number;
+
+  const PADDING = 6;
+
+  switch (direction) {
+    case "up": {
+      startX = startBindingElement.x + startBindingElement.width / 2;
+      startY = startBindingElement.y - PADDING;
+      break;
+    }
+    case "down": {
+      startX = startBindingElement.x + startBindingElement.width / 2;
+      startY = startBindingElement.y + startBindingElement.height + PADDING;
+      break;
+    }
+    case "right": {
+      startX = startBindingElement.x + startBindingElement.width + PADDING;
+      startY = startBindingElement.y + startBindingElement.height / 2;
+      break;
+    }
+    case "left": {
+      startX = startBindingElement.x - PADDING;
+      startY = startBindingElement.y + startBindingElement.height / 2;
+      break;
+    }
+  }
+
+  let endX: number;
+  let endY: number;
+
+  switch (direction) {
+    case "up": {
+      endX = endBindingElement.x + endBindingElement.width / 2 - startX;
+      endY = endBindingElement.y + endBindingElement.height - startY + PADDING;
+      break;
+    }
+    case "down": {
+      endX = endBindingElement.x + endBindingElement.width / 2 - startX;
+      endY = endBindingElement.y - startY - PADDING;
+      break;
+    }
+    case "right": {
+      endX = endBindingElement.x - startX - PADDING;
+      endY = endBindingElement.y - startY + endBindingElement.height / 2;
+      break;
+    }
+    case "left": {
+      endX = endBindingElement.x + endBindingElement.width - startX + PADDING;
+      endY = endBindingElement.y - startY + endBindingElement.height / 2;
+      break;
+    }
+  }
+
+  const bindingArrow = newArrowElement({
+    type: "arrow",
+    x: startX,
+    y: startY,
+    startArrowhead: null,
+    endArrowhead: appState.currentItemEndArrowhead,
+    strokeColor: startBindingElement.strokeColor,
+    strokeStyle: startBindingElement.strokeStyle,
+    strokeWidth: startBindingElement.strokeWidth,
+    opacity: startBindingElement.opacity,
+    roughness: startBindingElement.roughness,
+    points: [pointFrom(0, 0), pointFrom(endX, endY)],
+    elbowed: true,
+  });
+
+  bindLinearElement(
+    bindingArrow,
+    startBindingElement,
+    "start",
+    elementsMap as NonDeletedSceneElementsMap,
+  );
+  bindLinearElement(
+    bindingArrow,
+    endBindingElement,
+    "end",
+    elementsMap as NonDeletedSceneElementsMap,
+  );
+
+  const changedElements = new Map<string, OrderedExcalidrawElement>();
+  changedElements.set(
+    startBindingElement.id,
+    startBindingElement as OrderedExcalidrawElement,
+  );
+  changedElements.set(
+    endBindingElement.id,
+    endBindingElement as OrderedExcalidrawElement,
+  );
+  changedElements.set(
+    bindingArrow.id,
+    bindingArrow as OrderedExcalidrawElement,
+  );
+
+  LinearElementEditor.movePoints(bindingArrow, [
+    {
+      index: 1,
+      point: bindingArrow.points[1],
+    },
+  ]);
+
+  const update = updateElbowArrowPoints(
+    bindingArrow,
+    toBrandedType<NonDeletedSceneElementsMap>(
+      new Map([
+        ...elementsMap.entries(),
+        [startBindingElement.id, startBindingElement],
+        [endBindingElement.id, endBindingElement],
+        [bindingArrow.id, bindingArrow],
+      ] as [string, Ordered<ExcalidrawElement>][]),
+    ),
+    { points: bindingArrow.points },
+  );
+
+  return {
+    ...bindingArrow,
+    ...update,
+  };
+};
+
+export class FlowChartNavigator {
+  isExploring: boolean = false;
+  // nodes that are ONE link away (successor and predecessor both included)
+  private sameLevelNodes: ExcalidrawElement[] = [];
+  private sameLevelIndex: number = 0;
+  // set it to the opposite of the defalut creation direction
+  private direction: LinkDirection | null = null;
+  // for speedier navigation
+  private visitedNodes: Set<ExcalidrawElement["id"]> = new Set();
+
+  clear() {
+    this.isExploring = false;
+    this.sameLevelNodes = [];
+    this.sameLevelIndex = 0;
+    this.direction = null;
+    this.visitedNodes.clear();
+  }
+
+  exploreByDirection(
+    element: ExcalidrawElement,
+    elementsMap: ElementsMap,
+    direction: LinkDirection,
+  ): ExcalidrawElement["id"] | null {
+    if (!isBindableElement(element)) {
+      return null;
+    }
+
+    // clear if going at a different direction
+    if (direction !== this.direction) {
+      this.clear();
+    }
+
+    // add the current node to the visited
+    if (!this.visitedNodes.has(element.id)) {
+      this.visitedNodes.add(element.id);
+    }
+
+    /**
+     * CASE:
+     * - already started exploring, AND
+     * - there are multiple nodes at the same level, AND
+     * - still going at the same direction, AND
+     *
+     * RESULT:
+     * - loop through nodes at the same level
+     *
+     * WHY:
+     * - provides user the capability to loop through nodes at the same level
+     */
+    if (
+      this.isExploring &&
+      direction === this.direction &&
+      this.sameLevelNodes.length > 1
+    ) {
+      this.sameLevelIndex =
+        (this.sameLevelIndex + 1) % this.sameLevelNodes.length;
+
+      return this.sameLevelNodes[this.sameLevelIndex].id;
+    }
+
+    const nodes = [
+      ...getSuccessors(element, elementsMap, direction),
+      ...getPredecessors(element, elementsMap, direction),
+    ];
+
+    /**
+     * CASE:
+     * - just started exploring at the given direction
+     *
+     * RESULT:
+     * - go to the first node in the given direction
+     */
+    if (nodes.length > 0) {
+      this.sameLevelIndex = 0;
+      this.isExploring = true;
+      this.sameLevelNodes = nodes;
+      this.direction = direction;
+      this.visitedNodes.add(nodes[0].id);
+
+      return nodes[0].id;
+    }
+
+    /**
+     * CASE:
+     * - (just started exploring or still going at the same direction) OR
+     * - there're no nodes at the given direction
+     *
+     * RESULT:
+     * - go to some other unvisited linked node
+     *
+     * WHY:
+     * - provide a speedier navigation from a given node to some predecessor
+     *   without the user having to change arrow key
+     */
+    if (direction === this.direction || !this.isExploring) {
+      if (!this.isExploring) {
+        // just started and no other nodes at the given direction
+        // so the current node is technically the first visited node
+        // (this is needed so that we don't get stuck between looping through )
+        this.visitedNodes.add(element.id);
+      }
+
+      const otherDirections: LinkDirection[] = [
+        "up",
+        "right",
+        "down",
+        "left",
+      ].filter((dir): dir is LinkDirection => dir !== direction);
+
+      const otherLinkedNodes = otherDirections
+        .map((dir) => [
+          ...getSuccessors(element, elementsMap, dir),
+          ...getPredecessors(element, elementsMap, dir),
+        ])
+        .flat()
+        .filter((linkedNode) => !this.visitedNodes.has(linkedNode.id));
+
+      for (const linkedNode of otherLinkedNodes) {
+        if (!this.visitedNodes.has(linkedNode.id)) {
+          this.visitedNodes.add(linkedNode.id);
+          this.isExploring = true;
+          this.direction = direction;
+          return linkedNode.id;
+        }
+      }
+    }
+
+    return null;
+  }
+}
+
+export class FlowChartCreator {
+  isCreatingChart: boolean = false;
+  private numberOfNodes: number = 0;
+  private direction: LinkDirection | null = "right";
+  pendingNodes: PendingExcalidrawElements | null = null;
+
+  createNodes(
+    startNode: ExcalidrawFlowchartNodeElement,
+    elementsMap: ElementsMap,
+    appState: AppState,
+    direction: LinkDirection,
+  ) {
+    if (direction !== this.direction) {
+      const { nextNode, bindingArrow } = addNewNode(
+        startNode,
+        elementsMap,
+        appState,
+        direction,
+      );
+
+      this.numberOfNodes = 1;
+      this.isCreatingChart = true;
+      this.direction = direction;
+      this.pendingNodes = [nextNode, bindingArrow];
+    } else {
+      this.numberOfNodes += 1;
+      const newNodes = addNewNodes(
+        startNode,
+        elementsMap,
+        appState,
+        direction,
+        this.numberOfNodes,
+      );
+
+      this.isCreatingChart = true;
+      this.direction = direction;
+      this.pendingNodes = newNodes;
+    }
+
+    // add pending nodes to the same frame as the start node
+    // if every pending node is at least intersecting with the frame
+    if (startNode.frameId) {
+      const frame = elementsMap.get(startNode.frameId);
+
+      invariant(
+        frame && isFrameElement(frame),
+        "not an ExcalidrawFrameElement",
+      );
+
+      if (
+        frame &&
+        this.pendingNodes.every(
+          (node) =>
+            elementsAreInFrameBounds([node], frame, elementsMap) ||
+            elementOverlapsWithFrame(node, frame, elementsMap),
+        )
+      ) {
+        this.pendingNodes = this.pendingNodes.map((node) =>
+          mutateElement(
+            node,
+            {
+              frameId: startNode.frameId,
+            },
+            false,
+          ),
+        );
+      }
+    }
+  }
+
+  clear() {
+    this.isCreatingChart = false;
+    this.pendingNodes = null;
+    this.direction = null;
+    this.numberOfNodes = 0;
+  }
+}
+
+export const isNodeInFlowchart = (
+  element: ExcalidrawFlowchartNodeElement,
+  elementsMap: ElementsMap,
+) => {
+  for (const [, el] of elementsMap) {
+    if (
+      el.type === "arrow" &&
+      (el.startBinding?.elementId === element.id ||
+        el.endBinding?.elementId === element.id)
+    ) {
+      return true;
+    }
+  }
+
+  return false;
+};