From b9582ea93dd9024cb6bc2349aeb5f1ac2819848d Mon Sep 17 00:00:00 2001
From: Dan Fairburn <47511336+dfairburn@users.noreply.github.com>
Date: Wed, 23 Jun 2021 14:23:02 +0100
Subject: [PATCH] Dashboard: Allow more than 26 queries per panel. (#35442)

* Dashboard: Allow more than 26 queries per panel.

Fixes #4978

* Chore: Remove underscores from helper function names

Co-authored-by: Danyal Fairburn <danyal.fairburn@bt.com>
---
 public/app/core/utils/query.test.ts | 36 ++++++++++++++---------------
 public/app/core/utils/query.ts      | 26 +++++++++++++--------
 2 files changed, 34 insertions(+), 28 deletions(-)

diff --git a/public/app/core/utils/query.test.ts b/public/app/core/utils/query.test.ts
index c6a46b181e0..00c69667432 100644
--- a/public/app/core/utils/query.test.ts
+++ b/public/app/core/utils/query.test.ts
@@ -1,30 +1,30 @@
 import { DataQuery } from '@grafana/data';
 import { getNextRefIdChar } from './query';
 
-const dataQueries: DataQuery[] = [
-  {
-    refId: 'A',
-  },
-  {
-    refId: 'B',
-  },
-  {
-    refId: 'C',
-  },
-  {
-    refId: 'D',
-  },
-  {
-    refId: 'E',
-  },
-];
+function dataQueryHelper(ids: string[]): DataQuery[] {
+  return ids.map((letter) => {
+    return { refId: letter };
+  });
+}
+
+const singleDataQuery: DataQuery[] = dataQueryHelper('ABCDE'.split(''));
+const outOfOrderDataQuery: DataQuery[] = dataQueryHelper('ABD'.split(''));
+const singleExtendedDataQuery: DataQuery[] = dataQueryHelper('ABCDEFGHIJKLMNOPQRSTUVWXYZ'.split(''));
 
 describe('Get next refId char', () => {
   it('should return next char', () => {
-    expect(getNextRefIdChar(dataQueries)).toEqual('F');
+    expect(getNextRefIdChar(singleDataQuery)).toEqual('F');
   });
 
   it('should get first char', () => {
     expect(getNextRefIdChar([])).toEqual('A');
   });
+
+  it('should get the first avaliable character if a query has been deleted out of order', () => {
+    expect(getNextRefIdChar(outOfOrderDataQuery)).toEqual('C');
+  });
+
+  it('should append a new char and start from AA when Z is reached', () => {
+    expect(getNextRefIdChar(singleExtendedDataQuery)).toEqual('AA');
+  });
 });
diff --git a/public/app/core/utils/query.ts b/public/app/core/utils/query.ts
index d0118d10c33..b0823afe47d 100644
--- a/public/app/core/utils/query.ts
+++ b/public/app/core/utils/query.ts
@@ -1,16 +1,12 @@
-import { every, find } from 'lodash';
 import { DataQuery } from '@grafana/data';
 
 export const getNextRefIdChar = (queries: DataQuery[]): string => {
-  const letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
-
-  return (
-    find(letters, (refId) => {
-      return every(queries, (other) => {
-        return other.refId !== refId;
-      });
-    }) ?? 'NA'
-  );
+  for (let num = 0; ; num++) {
+    const refId = getRefId(num);
+    if (!queries.some((query) => query.refId === refId)) {
+      return refId;
+    }
+  }
 };
 
 export function addQuery(queries: DataQuery[], query?: Partial<DataQuery>): DataQuery[] {
@@ -35,3 +31,13 @@ export function isDataQuery(url: string): boolean {
 export function isLocalUrl(url: string) {
   return !url.match(/^http/);
 }
+
+function getRefId(num: number): string {
+  const letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
+
+  if (num < letters.length) {
+    return letters[num];
+  } else {
+    return getRefId(Math.floor(num / letters.length) - 1) + letters[num % letters.length];
+  }
+}