change average price to median price on the dashboard (#300)

* change average price to median price on the dashboard

* Use more efficient median calculation

Co-authored-by: Christian Kellner <weakmap@gmail.com>

* Fix applied suggestion artifacts

* Update sql query and js sort function

* Group sql statement by id

* Revert sort function change

---------

Co-authored-by: Christian Kellner <weakmap@gmail.com>

lib/api/routes/dashboardRouter.js

@@ -37,7 +37,7 @@ dashboardRouter.get('/', async (req, res) => {
   const totalJobs = jobs.length;
   const totalListings = jobs.reduce((sum, j) => sum + (j.numberOfFoundListings || 0), 0);
   const jobIds = jobs.map((j) => j.id);
-  const { numberOfActiveListings, avgPriceOfListings } = getListingsKpisForJobIds(jobIds);
+  const { numberOfActiveListings, medianPriceOfListings } = getListingsKpisForJobIds(jobIds);
   // Build Pie data in a simple shape the frontend can consume directly
   // Shape: { labels: string[], values: number[] } with values as percentages
   const providerPieRaw = getProviderDistributionForJobIds(jobIds);
@@ -63,7 +63,7 @@ dashboardRouter.get('/', async (req, res) => {
       totalJobs,
       totalListings,
       numberOfActiveListings,
-      avgPriceOfListings,
+      medianPriceOfListings,
     },
     pie: providerPie,
   };

lib/services/storage/listingsStorage.js

@@ -29,33 +29,47 @@ export const getKnownListingHashesForJobAndProvider = (jobId, providerId) => {
  * Compute KPI aggregates for a given set of job IDs from the listings table.
  *
  * - numberOfActiveListings: count of listings where is_active = 1
- * - avgPriceOfListings: average of numeric price, rounded to nearest integer
+ * - medianPriceOfListings: median of numeric price, rounded to nearest integer
  *
  * When no jobIds are provided, returns zeros.
  *
  * @param {string[]} jobIds
- * @returns {{ numberOfActiveListings: number, avgPriceOfListings: number }}
+ * @returns {{ numberOfActiveListings: number, medianPriceOfListings: number }}
  */
 export const getListingsKpisForJobIds = (jobIds = []) => {
   if (!Array.isArray(jobIds) || jobIds.length === 0) {
-    return { numberOfActiveListings: 0, avgPriceOfListings: 0 };
+    return { numberOfActiveListings: 0, medianPriceOfListings: 0 };
   }
 
   const placeholders = jobIds.map(() => '?').join(',');
-  const row =
-    SqliteConnection.query(
-      `SELECT
-          SUM(CASE WHEN is_active = 1 THEN 1 ELSE 0 END) AS activeCount,
-          AVG(price) AS avgPrice
-       FROM listings
-       WHERE job_id IN (${placeholders})
-         AND manually_deleted = 0`,
-      jobIds,
-    )[0] || {};
+  const rows = SqliteConnection.query(
+    `SELECT
+      SUM(CASE WHEN is_active = 1 THEN 1 ELSE 0 END) OVER() AS active_count,
+      price
+    FROM listings
+    WHERE job_id IN (${placeholders})
+      AND manually_deleted = 0
+    GROUP BY
+      id`,
+    jobIds,
+  );
+
+  const activeCount = rows[0]?.active_count ?? 0;
+
+  const prices = rows
+    .map((r) => r.price)
+    .filter((p) => p !== null)
+    .sort((a, b) => a - b);
+
+  let medianPrice = 0;
+  if (prices.length > 0) {
+    const mid = Math.floor(prices.length / 2);
+    medianPrice = prices.length % 2 !== 0 ? prices[mid] : (prices[mid - 1] + prices[mid]) / 2;
+  }
 
   return {
-    numberOfActiveListings: Number(row.activeCount || 0),
-    avgPriceOfListings: row?.avgPrice == null ? 0 : Math.round(Number(row.avgPrice)),
+    numberOfActiveListings: activeCount,
+    medianPriceOfListings: medianPrice,
   };
 };
 

ui/src/views/dashboard/Dashboard.jsx

@@ -127,18 +127,18 @@ export default function Dashboard() {
         </Col>
         <Col xs={24} sm={12} md={12} lg={6} xl={6}>
           <KpiCard
-            title="Avg. Price"
+            title="Median Price"
             color="purple"
             value={`${
-              !kpis.avgPriceOfListings
+              !kpis.medianPriceOfListings
                 ? '---'
                 : new Intl.NumberFormat('de-DE', {
                     style: 'currency',
                     currency: 'EUR',
-                  }).format(kpis.avgPriceOfListings)
+                  }).format(kpis.medianPriceOfListings)
             }`}
             icon={<IconNoteMoney />}
-            description="Avg. Price of listings"
+            description="Median Price of listings"
           />
         </Col>
       </Row>