[Maps] Move sort out of top hits configuration for ES documents source

docs/maps/maps-aggregations.asciidoc

@@ -36,8 +36,6 @@ To enable most recent entities, click "Show most recent documents by entity" and
 
 . Set *Entity* to the field that identifies entities in your documents.
 This field will be used in the terms aggregation to group your documents into entity buckets.
-. Set *Time* to the date field that puts your documents in chronological order.
-This field will be used to sort your documents in the top hits aggregation.
 . Set *Documents per entity* to configure the maximum number of documents accumulated per entity.
 
 [role="xpack"]

x-pack/legacy/plugins/maps/common/constants.js

@@ -39,6 +39,11 @@ export const LAYER_TYPE = {
   HEATMAP: 'HEATMAP'
 };
 
+export const SORT_ORDER = {
+  ASC: 'asc',
+  DESC: 'desc',
+};
+
 export const EMS_TMS = 'EMS_TMS';
 export const EMS_FILE = 'EMS_FILE';
 export const ES_GEO_GRID = 'ES_GEO_GRID';

x-pack/legacy/plugins/maps/common/migrations/top_hits_time_to_sort.js

@@ -0,0 +1,35 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import _ from 'lodash';
+import {  ES_SEARCH, SORT_ORDER } from '../constants';
+
+function isEsDocumentSource(layerDescriptor) {
+  const sourceType = _.get(layerDescriptor, 'sourceDescriptor.type');
+  return sourceType === ES_SEARCH;
+}
+
+export function topHitsTimeToSort({ attributes }) {
+  if (!attributes.layerListJSON) {
+    return attributes;
+  }
+
+  const layerList = JSON.parse(attributes.layerListJSON);
+  layerList.forEach((layerDescriptor) => {
+    if (isEsDocumentSource(layerDescriptor)) {
+      if (_.has(layerDescriptor, 'sourceDescriptor.topHitsTimeField')) {
+        layerDescriptor.sourceDescriptor.sortField = layerDescriptor.sourceDescriptor.topHitsTimeField;
+        layerDescriptor.sourceDescriptor.sortOrder = SORT_ORDER.DESC;
+        delete layerDescriptor.sourceDescriptor.topHitsTimeField;
+      }
+    }
+  });
+
+  return {
+    ...attributes,
+    layerListJSON: JSON.stringify(layerList),
+  };
+}

x-pack/legacy/plugins/maps/common/migrations/top_hits_time_to_sort.test.js

@@ -0,0 +1,60 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+/* eslint max-len: 0 */
+
+import { topHitsTimeToSort } from './top_hits_time_to_sort';
+
+describe('topHitsTimeToSort', () => {
+
+  test('Should handle missing layerListJSON attribute', () => {
+    const attributes = {
+      title: 'my map',
+    };
+    expect(topHitsTimeToSort({ attributes })).toEqual({
+      title: 'my map',
+    });
+  });
+
+  test('Should move topHitsTimeField to sortField for ES documents sources', () => {
+    const layerListJSON = JSON.stringify([
+      {
+        sourceDescriptor: {
+          type: 'ES_SEARCH',
+          topHitsSplitField: 'gpsId',
+          topHitsTimeField: '@timestamp',
+        }
+      }
+    ]);
+    const attributes = {
+      title: 'my map',
+      layerListJSON
+    };
+    expect(topHitsTimeToSort({ attributes })).toEqual({
+      title: 'my map',
+      layerListJSON: '[{\"sourceDescriptor\":{\"type\":\"ES_SEARCH\",\"topHitsSplitField\":\"gpsId\",\"sortField\":\"@timestamp\",\"sortOrder\":\"desc\"}}]',
+    });
+  });
+
+  test('Should handle ES documents sources without topHitsTimeField', () => {
+    const layerListJSON = JSON.stringify([
+      {
+        sourceDescriptor: {
+          type: 'ES_SEARCH',
+          topHitsSplitField: 'gpsId',
+        }
+      }
+    ]);
+    const attributes = {
+      title: 'my map',
+      layerListJSON
+    };
+    expect(topHitsTimeToSort({ attributes })).toEqual({
+      title: 'my map',
+      layerListJSON,
+    });
+  });
+});

x-pack/legacy/plugins/maps/migrations.js

@@ -6,6 +6,7 @@
 
 import { extractReferences } from './common/migrations/references';
 import { emsRasterTileToEmsVectorTile } from './common/migrations/ems_raster_tile_to_ems_vector_tile';
+import { topHitsTimeToSort } from './common/migrations/top_hits_time_to_sort';
 
 export const migrations = {
   'map': {
@@ -21,6 +22,14 @@ export const migrations = {
     '7.4.0': (doc) => {
       const attributes = emsRasterTileToEmsVectorTile(doc);
 
+      return {
+        ...doc,
+        attributes,
+      };
+    },
+    '7.5.0': (doc) => {
+      const attributes = topHitsTimeToSort(doc);
+
       return {
         ...doc,
         attributes,