SQL Expressions: Resizable code-editor (#101407)

* Resizeable SQL expressions text-area

Generated by an LLM for me - we'll see. It expands quite large on first
page-load

* Switch to useLayoutEffect to avoid visual flashing

* Get the LLM to rewrite the approach, inspired by InfluxDB

The Influx DB text-area is also resizable vertically, but that one isn't
a Monaco editor (we need to tell Monaco to update its own size when the
outer div is resized), so this is necessarily a little more complex than
Influx. But still this approach looks simpler: The Javascript here is
shorter

* Start at 240px, to match the current default size

Question: Is there a better approach to achieve this?

* Don't clip the bottom border of the Monaco editor

* Fix linting errors

public/app/features/expressions/components/SqlExpr.tsx

@@ -1,10 +1,15 @@
-import { useMemo } from 'react';
+import { css } from '@emotion/css';
+import { useMemo, useRef, useEffect, useState } from 'react';
 
 import { SelectableValue } from '@grafana/data';
 import { SQLEditor } from '@grafana/plugin-ui';
+import { useStyles2 } from '@grafana/ui';
 
 import { ExpressionQuery } from '../types';
 
+// Account for Monaco editor's border to prevent clipping
+const EDITOR_BORDER_ADJUSTMENT = 2; // 1px border on top and bottom
+
 interface Props {
   refIds: Array<SelectableValue<string>>;
   query: ExpressionQuery;
@@ -13,8 +18,10 @@ interface Props {
 
 export const SqlExpr = ({ onChange, refIds, query }: Props) => {
   const vars = useMemo(() => refIds.map((v) => v.value!), [refIds]);
-
   const initialQuery = `select * from ${vars[0]} limit 1`;
+  const styles = useStyles2(getStyles);
+  const containerRef = useRef<HTMLDivElement>(null);
+  const [dimensions, setDimensions] = useState({ height: 0 });
 
   const onEditorChange = (expression: string) => {
     onChange({
@@ -23,5 +30,37 @@ export const SqlExpr = ({ onChange, refIds, query }: Props) => {
     });
   };
 
-  return <SQLEditor query={query.expression || initialQuery} onChange={onEditorChange}></SQLEditor>;
+  // Set up resize observer to handle container resizing
+  useEffect(() => {
+    if (!containerRef.current) {
+      return;
+    }
+
+    const resizeObserver = new ResizeObserver((entries) => {
+      const { height } = entries[0].contentRect;
+      setDimensions({ height });
+    });
+
+    resizeObserver.observe(containerRef.current);
+    return () => resizeObserver.disconnect();
+  }, []);
+
+  return (
+    <div ref={containerRef} className={styles.editorContainer}>
+      <SQLEditor
+        query={query.expression || initialQuery}
+        onChange={onEditorChange}
+        height={dimensions.height - EDITOR_BORDER_ADJUSTMENT}
+      />
+    </div>
+  );
 };
+
+const getStyles = () => ({
+  editorContainer: css({
+    height: '240px',
+    resize: 'vertical',
+    overflow: 'auto',
+    minHeight: '100px',
+  }),
+});