improvement: allow users to expand collapsed environment view header

frontend/src/hooks/index.ts

@@ -4,6 +4,7 @@ export { usePagination } from "./usePagination";
 export { usePersistentState } from "./usePersistentState";
 export { usePopUp } from "./usePopUp";
 export { useResetPageHelper } from "./useResetPageHelper";
+export * from "./useResizableHeaderHeight";
 export { useSyntaxHighlight } from "./useSyntaxHighlight";
 export { useTimedReset } from "./useTimedReset";
 export { useToggle } from "./useToggle";

frontend/src/hooks/useResizableHeaderHeight.tsx

@@ -0,0 +1,71 @@
+import { MouseEvent, useCallback, useEffect, useRef, useState } from "react";
+
+type Params = {
+  minHeight: number;
+  maxHeight: number;
+  initialHeight: number;
+};
+
+export const useResizableHeaderHeight = ({ minHeight, maxHeight, initialHeight }: Params) => {
+  const [headerHeight, setHeaderHeight] = useState(initialHeight);
+  const [isResizing, setIsResizing] = useState(false);
+  const startY = useRef(0);
+  const startHeight = useRef(0);
+
+  const handleMouseDown = useCallback(
+    (e: MouseEvent<HTMLDivElement>) => {
+      e.preventDefault();
+      e.stopPropagation();
+      setIsResizing(true);
+      startY.current = e.clientY;
+      startHeight.current = headerHeight;
+    },
+    [headerHeight]
+  );
+
+  const handleMouseMove = useCallback(
+    (e: MouseEvent) => {
+      if (!isResizing) return;
+
+      const deltaY = e.clientY - startY.current;
+      const newHeight = Math.max(minHeight, Math.min(maxHeight, startHeight.current + deltaY));
+
+      setHeaderHeight(newHeight);
+    },
+    [isResizing]
+  );
+
+  const handleMouseUp = useCallback(() => {
+    setIsResizing(false);
+  }, []);
+
+  useEffect(() => {
+    if (isResizing) {
+      document.addEventListener(
+        "mousemove",
+        // @ts-expect-error native discrepancy
+        handleMouseMove
+      );
+      document.addEventListener("mouseup", handleMouseUp);
+      document.body.style.cursor = "ns-resize";
+      document.body.style.userSelect = "none";
+    }
+
+    return () => {
+      document.removeEventListener(
+        "mousemove",
+        // @ts-expect-error native discrepancy
+        handleMouseMove
+      );
+      document.removeEventListener("mouseup", handleMouseUp);
+      document.body.style.cursor = "";
+      document.body.style.userSelect = "";
+    };
+  }, [isResizing, handleMouseMove, handleMouseUp]);
+
+  return {
+    headerHeight,
+    handleMouseDown,
+    isResizing
+  };
+};