[system_tracking] Display error when no scans for a particular date

awx/ui/static/js/system-tracking/fact-data-table/fact-data-table.directive.js

@@ -9,6 +9,8 @@ export default
                                 rightHostname: '=',
                                 leftScanDate: '=',
                                 rightScanDate: '=',
+                                leftDataNoScans: '=',
+                                rightDataNoScans: '=',
                                 factData: '='
                             }
                     };

awx/ui/static/js/system-tracking/fact-data-table/fact-data-table.partial.html

@@ -6,11 +6,13 @@
           </span>
         </h3>
         <h3 class="FactDataTable-column FactDataTableHeading">
-          <span class="FactDataTableHeading-host">{{leftHostname}}</span>
+          <span ng-if="leftDataNoScans">No scans for {{leftHostname}} on</span>
+          <span class="FactDataTableHeading-host" ng-if="!leftDataNoScans">{{leftHostname}}</span>
           <span class="FactDataTableHeading-date">{{leftScanDate|longDate}}</span>
         </h3>
         <h3 class="FactDataTable-column FactDataTableHeading">
-          <span class="FactDataTableHeading-host">{{rightHostname}}</span>
+          <span ng-if="rightDataNoScans">No scans for {{rightHostname}} on</span>
+          <span class="FactDataTableHeading-host" ng-if="!rightDataNoScans">{{rightHostname}}</span>
           <span class="FactDataTableHeading-date">{{rightScanDate|longDate}}</span>
         </h3>
     </div>

awx/ui/static/js/system-tracking/system-tracking.controller.js

@@ -63,6 +63,9 @@ function controller($rootScope,
             rightRange = searchConfig.leftRange;
         }
 
+        $scope.leftDataNoScans = false;
+        $scope.rightDataNoScans = false;
+
         waitIndicator('start');
 
         return getDataForComparison(
@@ -73,8 +76,19 @@ function controller($rootScope,
                 .then(function(responses) {
                     var data = _.pluck(responses, 'fact');
 
-                    $scope.leftScanDate = moment(responses[0].timestamp);
+                    if (_.isEmpty(data[0])) {
-                    $scope.rightScanDate = moment(responses[1].timestamp);
+                        $scope.leftDataNoScans = true;
+                        $scope.leftScanDate = $scope.leftDate;
+                    } else {
+                        $scope.leftScanDate = moment(responses[0].timestamp);
+                    }
+
+                    if (_.isEmpty(data[1])) {
+                        $scope.rightDataNoScans = true;
+                        $scope.rightScanDate = $scope.rightDate;
+                    } else {
+                        $scope.rightScanDate = moment(responses[1].timestamp);
+                    }
 
                     return data;
                 })

awx/ui/static/js/system-tracking/system-tracking.partial.html

@@ -45,6 +45,8 @@
         right-hostname="rightHostname"
         left-scan-date="leftScanDate"
         right-scan-date="rightScanDate"
+        left-data-no-scans="leftDataNoScans"
+        right-data-no-scans="rightDataNoScans"
         fact-data="factData">
     </fact-data-table>
 </section>