[Lens] Thresholds: auto fit thresholds into vertical axis (#113238)

* ✨ Make threshold fit into view automatically

* 🐛 do not compute axis threshold extends if no threshold is present

* ✅ One more fix for 0-based extends and tests

* 📝 fix typo

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

x-pack/plugins/lens/public/xy_visualization/expression.test.tsx

@@ -330,6 +330,48 @@ function sampleArgs() {
   return { data, args };
 }
 
+function sampleArgsWithThreshold(thresholdValue: number = 150) {
+  const { data, args } = sampleArgs();
+
+  return {
+    data: {
+      ...data,
+      tables: {
+        ...data.tables,
+        threshold: {
+          type: 'datatable',
+          columns: [
+            {
+              id: 'threshold-a',
+              meta: { params: { id: 'number' }, type: 'number' },
+              name: 'Static value',
+            },
+          ],
+          rows: [{ 'threshold-a': thresholdValue }],
+        },
+      },
+    } as LensMultiTable,
+    args: {
+      ...args,
+      layers: [
+        ...args.layers,
+        {
+          layerType: layerTypes.THRESHOLD,
+          accessors: ['threshold-a'],
+          layerId: 'threshold',
+          seriesType: 'line',
+          xScaleType: 'linear',
+          yScaleType: 'linear',
+          palette: mockPaletteOutput,
+          isHistogram: false,
+          hide: true,
+          yConfig: [{ axisMode: 'left', forAccessor: 'threshold-a', type: 'lens_xy_yConfig' }],
+        },
+      ],
+    } as XYArgs,
+  };
+}
+
 describe('xy_expression', () => {
   describe('configs', () => {
     test('legendConfig produces the correct arguments', () => {
@@ -829,6 +871,53 @@ describe('xy_expression', () => {
           max: undefined,
         });
       });
+
+      test('it does include threshold values when in full extent mode', () => {
+        const { data, args } = sampleArgsWithThreshold();
+
+        const component = shallow(<XYChart {...defaultProps} data={data} args={args} />);
+        expect(component.find(Axis).find('[id="left"]').prop('domain')).toEqual({
+          fit: false,
+          min: 0,
+          max: 150,
+        });
+      });
+
+      test('it should ignore threshold values when set to custom extents', () => {
+        const { data, args } = sampleArgsWithThreshold();
+
+        const component = shallow(
+          <XYChart
+            {...defaultProps}
+            data={data}
+            args={{
+              ...args,
+              yLeftExtent: {
+                type: 'lens_xy_axisExtentConfig',
+                mode: 'custom',
+                lowerBound: 123,
+                upperBound: 456,
+              },
+            }}
+          />
+        );
+        expect(component.find(Axis).find('[id="left"]').prop('domain')).toEqual({
+          fit: false,
+          min: 123,
+          max: 456,
+        });
+      });
+
+      test('it should work for negative values in thresholds', () => {
+        const { data, args } = sampleArgsWithThreshold(-150);
+
+        const component = shallow(<XYChart {...defaultProps} data={data} args={args} />);
+        expect(component.find(Axis).find('[id="left"]').prop('domain')).toEqual({
+          fit: false,
+          min: -150,
+          max: 5,
+        });
+      });
     });
 
     test('it has xDomain undefined if the x is not a time scale or a histogram', () => {

x-pack/plugins/lens/public/xy_visualization/expression.tsx

@@ -117,6 +117,8 @@ export function calculateMinInterval({ args: { layers }, data }: XYChartProps) {
   return intervalDuration.as('milliseconds');
 }
 
+const isPrimitive = (value: unknown): boolean => value != null && typeof value !== 'object';
+
 export const getXyChartRenderer = (dependencies: {
   formatFactory: FormatFactory;
   chartsThemeService: ChartsPluginStart['theme'];
@@ -395,6 +397,41 @@ export function XYChart({
         min = extent.lowerBound;
         max = extent.upperBound;
       }
+    } else {
+      const axisHasThreshold = thresholdLayers.some(({ yConfig }) =>
+        yConfig?.some(({ axisMode }) => axisMode === axis.groupId)
+      );
+      if (!fit && axisHasThreshold) {
+        // Remove this once the chart will support automatic annotation fit for other type of charts
+        for (const series of axis.series) {
+          const table = data.tables[series.layer];
+          for (const row of table.rows) {
+            for (const column of table.columns) {
+              if (column.id === series.accessor) {
+                const value = row[column.id];
+                if (typeof value === 'number') {
+                  // keep the 0 in view
+                  max = Math.max(value, max || 0, 0);
+                  min = Math.min(value, min || 0, 0);
+                }
+              }
+            }
+          }
+        }
+        for (const { layerId, yConfig } of thresholdLayers) {
+          const table = data.tables[layerId];
+          for (const { axisMode, forAccessor } of yConfig || []) {
+            if (axis.groupId === axisMode) {
+              for (const row of table.rows) {
+                const value = row[forAccessor];
+                // keep the 0 in view
+                max = Math.max(value, max || 0, 0);
+                min = Math.min(value, min || 0, 0);
+              }
+            }
+          }
+        }
+      }
     }
 
     return {
@@ -652,9 +689,6 @@ export function XYChart({
 
           const table = data.tables[layerId];
 
-          const isPrimitive = (value: unknown): boolean =>
-            value != null && typeof value !== 'object';
-
           // what if row values are not primitive? That is the case of, for instance, Ranges
           // remaps them to their serialized version with the formatHint metadata
           // In order to do it we need to make a copy of the table as the raw one is required for more features (filters, etc...) later on