Monaco: add suggestions for template variables (#25921)

* now with suggestions

* using suggestions API

* using variable suggestions

* using variable suggestions

* show variables

* minor cleanup

* add @alpha warning

* Do not produce data variables if panel does not support queries

Co-authored-by: Dominik Prokop <dominik.prokop@grafana.com>

public/app/features/panel/panellinks/link_srv.ts

@@ -19,6 +19,7 @@ import {
   urlUtil,
   textUtil,
   DataLink,
+  PanelPlugin,
 } from '@grafana/data';
 
 const timeRangeVars = [
@@ -231,6 +232,18 @@ export const getCalculationValueDataLinksVariableSuggestions = (dataFrames: Data
   return [...seriesVars, ...fieldVars, ...valueVars, valueCalcVar, ...getPanelLinksVariableSuggestions()];
 };
 
+export const getPanelOptionsVariableSuggestions = (plugin: PanelPlugin, data?: DataFrame[]): VariableSuggestion[] => {
+  const dataVariables = plugin.meta.skipDataQuery ? [] : getDataFrameVars(data || []);
+  return [
+    ...dataVariables, // field values
+    ...templateSrv.getVariables().map(variable => ({
+      value: variable.name as string,
+      label: variable.name,
+      origin: VariableOrigin.Template,
+    })),
+  ];
+};
+
 export interface LinkService {
   getDataLinkUIModel: <T>(link: DataLink, scopedVars: ScopedVars, origin: T) => LinkModel<T>;
   getAnchorInfo: (link: any) => any;