fix: ttp stat show latest date (#6626)

Makes the time to production stats show the current value (latest date).
This aligns it with other stats on the page.

Closes #
[1-2203](https://linear.app/unleash/issue/1-2203/make-the-time-to-production-stats-show-the-latest-current-data)

---------

Signed-off-by: andreas-unleash <andreas@getunleash.ai>

frontend/src/component/executiveDashboard/hooks/useAvgTimeToProduction.test.ts

@@ -10,25 +10,39 @@ describe('useAvgTimeToProduction', () => {
         expect(result.current).toBe(0);
     });
 
-    test('calculates result.current time to production correctly', () => {
+    test('calculates average time to production based on the latest date correctly', () => {
         const projectsData = {
-            project1: [{ timeToProduction: 10 }, { timeToProduction: 20 }],
-            project2: [{ timeToProduction: 15 }, { timeToProduction: 25 }],
+            project1: [
+                { timeToProduction: 10, date: '2023-01-01' },
+                { timeToProduction: 20, date: '2023-02-01' },
+            ],
+            project2: [
+                { timeToProduction: 15, date: '2023-01-15' },
+                { timeToProduction: 25, date: '2023-02-15' },
+            ],
         } as any;
         const { result } = renderHook(() =>
             useAvgTimeToProduction(projectsData),
         );
-        expect(result.current).toBe(17.5);
+        // Expect average of the latest timeToProductions (20 from project1 and 25 from project2)
+        expect(result.current).toBe(22.5);
     });
 
-    test('ignores projects without time to production data', () => {
+    test('ignores projects without time to production data in their latest entries', () => {
         const projectsData = {
-            project1: [{ timeToProduction: 10 }, { timeToProduction: 20 }],
-            project2: [],
+            project1: [
+                { timeToProduction: 10, date: '2023-01-01' },
+                { timeToProduction: 20, date: '2023-02-01' },
+            ],
+            project2: [
+                { date: '2023-01-15' },
+                { timeToProduction: 25, date: '2023-01-10' },
+            ],
         } as any;
         const { result } = renderHook(() =>
             useAvgTimeToProduction(projectsData),
         );
-        expect(result.current).toBe(7.5);
+        // Since project2's latest entry doesn't have timeToProduction, only project1's latest is considered
+        expect(result.current).toBe(20);
     });
 });

frontend/src/component/executiveDashboard/hooks/useAvgTimeToProduction.ts

@@ -1,31 +1,43 @@
 import { useMemo } from 'react';
-import type { ExecutiveSummarySchema } from 'openapi';
+import type {
+    ExecutiveSummarySchema,
+    ExecutiveSummarySchemaProjectFlagTrendsItem,
+} from 'openapi';
 import type { GroupedDataByProject } from './useGroupedProjectTrends';
 
+const validTrend = (trend: ExecutiveSummarySchemaProjectFlagTrendsItem) =>
+    Boolean(trend) && Boolean(trend.timeToProduction);
+
 export const useAvgTimeToProduction = (
     projectsData: GroupedDataByProject<
         ExecutiveSummarySchema['projectFlagTrends']
     >,
 ) =>
     useMemo(() => {
-        const totalProjects = Object.keys(projectsData).length;
+        let totalProjects = Object.keys(projectsData).length;
 
         if (totalProjects === 0) {
             return 0;
         }
 
         const totalAvgTimeToProduction = Object.entries(projectsData).reduce(
             (acc, [_, trends]) => {
-                const validTrends = trends.filter(
-                    (trend) => trend.timeToProduction !== undefined,
+                const latestTrend = trends.reduce(
+                    (latest, current) =>
+                        new Date(latest.date) < new Date(current.date)
+                            ? current
+                            : latest,
+                    trends[0],
                 );
-                const avgTimeToProduction =
-                    validTrends.reduce(
-                        (sum, item) => sum + (item.timeToProduction || 0),
-                        0,
-                    ) / (validTrends.length || 1);
 
-                return acc + (validTrends.length > 0 ? avgTimeToProduction : 0);
+                // If there's no valid latest trend, this project won't contribute to the average
+                if (!validTrend(latestTrend)) {
+                    totalProjects--;
+                    return acc;
+                }
+
+                const timeToProduction = latestTrend.timeToProduction || 0;
+                return acc + timeToProduction;
             },
             0,
         );