Extracted member activity fetching into new service

refs https://github.com/TryGhost/Team/issues/1277

- pulled timeline fetching from `members-stats` service to `members-activity` service ready for further refactoring to make fetching/processing more generic

ghost/admin/app/controllers/dashboard.js

@@ -7,6 +7,7 @@ import {tracked} from '@glimmer/tracking';
 export default class DashboardController extends Controller {
     @service feature;
     @service session;
+    @service membersActivity;
     @service membersStats;
     @service store;
     @service settings;
@@ -162,7 +163,7 @@ export default class DashboardController extends Controller {
 
     loadEvents() {
         this.eventsLoading = true;
-        this.membersStats.fetchTimeline({limit: 5}).then(({events}) => {
+        this.membersActivity.fetchTimeline({limit: 5}).then(({events}) => {
             this.eventsData = events;
             this.eventsLoading = false;
         }, (error) => {

ghost/admin/app/services/members-activity.js

@@ -1,5 +1,38 @@
 import Service from '@ember/service';
+import {inject as service} from '@ember/service';
+import {task} from 'ember-concurrency-decorators';
+
+const ONE_MINUTE = 1 * 60 * 1000;
 
 export default class MembersActivityService extends Service {
+    @service ajax;
+    @service ghostPaths;
 
+    _lastFetchedTimeline = null;
+    _lastFetchedTimelineLimit = null;
+
+    async fetchTimeline(options = {}) {
+        let staleData = this._lastFetchedTimeline && (new Date() - this._lastFetchedTimeline) > ONE_MINUTE;
+        let differentLimit = this._lastFetchedTimelineLimit && this._lastFetchedTimelineLimit !== options.limit;
+
+        if (this._fetchTimelineTask.isRunning) {
+            return this._fetchTimelineTask.last;
+        }
+
+        if (this.events && !staleData && !differentLimit) {
+            return this.events;
+        }
+
+        return this._fetchTimelineTask.perform(options.limit);
+    }
+
+    @task
+    *_fetchTimelineTask(limit) {
+        this._lastFetchedTimeline = new Date();
+        this._lastFetchedTimelineLimit = limit;
+        let eventsUrl = this.ghostPaths.url.api('members/events');
+        let events = yield this.ajax.request(eventsUrl, {data: {limit}});
+        this.events = events;
+        return events;
+    }
 }

ghost/admin/app/services/members-stats.js

@@ -35,21 +35,6 @@ export default class MembersStatsService extends Service {
         return this._fetchTask.perform();
     }
 
-    fetchTimeline(options = {}) {
-        let staleData = this._lastFetchedTimeline && (new Date() - this._lastFetchedTimeline) > ONE_MINUTE;
-        let differentLimit = this._lastFetchedTimelineLimit && this._lastFetchedTimelineLimit !== options.limit;
-
-        if (this._fetchTimelineTask.isRunning) {
-            return this._fetchTask.last;
-        }
-
-        if (this.events && !this._forceRefresh && !staleData && !differentLimit) {
-            return Promise.resolve(this.events);
-        }
-
-        return this._fetchTimelineTask.perform(options.limit);
-    }
-
     fetchCounts() {
         let staleData = this._lastFetchedCounts && (new Date() - this._lastFetchedCounts) > ONE_MINUTE;
 
@@ -235,14 +220,4 @@ export default class MembersStatsService extends Service {
         this.stats = stats;
         return stats;
     }
-
-    @task
-    *_fetchTimelineTask(limit) {
-        this._lastFetchedTimeline = new Date();
-        this._lastFetchedTimelineLimit = limit;
-        let eventsUrl = this.ghostPaths.url.api('members/events');
-        let events = yield this.ajax.request(eventsUrl, {data: {limit}});
-        this.events = events;
-        return events;
-    }
 }