feat: auto-position tooltip and suport overflowing container (#3631)

src/components/Tooltip.tsx

@@ -1,31 +1,92 @@
 import "./Tooltip.scss";
 
-import React from "react";
+import React, { useEffect } from "react";
+
+const getTooltipDiv = () => {
+  const existingDiv = document.querySelector<HTMLDivElement>(
+    ".excalidraw-tooltip",
+  );
+  if (existingDiv) {
+    return existingDiv;
+  }
+  const div = document.createElement("div");
+  document.body.appendChild(div);
+  div.classList.add("excalidraw-tooltip");
+  return div;
+};
+
+const updateTooltip = (
+  item: HTMLDivElement,
+  tooltip: HTMLDivElement,
+  label: string,
+  long: boolean,
+) => {
+  tooltip.classList.add("excalidraw-tooltip--visible");
+  tooltip.style.minWidth = long ? "50ch" : "10ch";
+  tooltip.style.maxWidth = long ? "50ch" : "15ch";
+
+  tooltip.textContent = label;
+
+  const {
+    x: itemX,
+    bottom: itemBottom,
+    top: itemTop,
+    width: itemWidth,
+  } = item.getBoundingClientRect();
+
+  const {
+    width: labelWidth,
+    height: labelHeight,
+  } = tooltip.getBoundingClientRect();
+
+  const viewportWidth = window.innerWidth;
+  const viewportHeight = window.innerHeight;
+
+  const margin = 5;
+
+  const left = itemX + itemWidth / 2 - labelWidth / 2;
+  const offsetLeft =
+    left + labelWidth >= viewportWidth ? left + labelWidth - viewportWidth : 0;
+
+  const top = itemBottom + margin;
+  const offsetTop =
+    top + labelHeight >= viewportHeight
+      ? itemBottom - itemTop + labelHeight + margin * 2
+      : 0;
+
+  Object.assign(tooltip.style, {
+    top: `${top - offsetTop}px`,
+    left: `${left - offsetLeft}px`,
+  });
+};
 
 type TooltipProps = {
   children: React.ReactNode;
   label: string;
-  position?: "above" | "below";
   long?: boolean;
 };
 
-export const Tooltip = ({
-  children,
-  label,
-  position = "below",
-  long = false,
-}: TooltipProps) => (
-  <div className="Tooltip">
-    <span
-      className={
-        position === "above"
-          ? "Tooltip__label Tooltip__label--above"
-          : "Tooltip__label Tooltip__label--below"
+export const Tooltip = ({ children, label, long = false }: TooltipProps) => {
+  useEffect(() => {
+    return () =>
+      getTooltipDiv().classList.remove("excalidraw-tooltip--visible");
+  }, []);
+
+  return (
+    <div
+      onPointerEnter={(event) =>
+        updateTooltip(
+          event.currentTarget as HTMLDivElement,
+          getTooltipDiv(),
+          label,
+          long,
+        )
+      }
+      onPointerLeave={() =>
+        getTooltipDiv().classList.remove("excalidraw-tooltip--visible")
       }
-      style={{ width: long ? "50ch" : "10ch" }}
     >
-      {label}
-    </span>
-    {children}
-  </div>
-);
+      {children}
+    </div>
+  );
+};