Add aggregated burndown forecast to CCP Metrics overview page

backend/helpers/vclHelpers.js

@@ -278,6 +278,116 @@ function computeVerticalBurndown(items) {
     };
 }
 
+/**
+ * Deduplicates devices by hostname, keeping the earliest non-null resolution_date.
+ * A device appearing in multiple metrics counts once.
+ *
+ * @param {Array<{ hostname: string, resolution_date: string|null, vertical: string }>} items
+ * @returns {Array<{ hostname: string, resolution_date: string|null, vertical: string }>}
+ */
+function deduplicateByHostname(items) {
+    const map = {};
+    for (const item of items) {
+        const key = item.hostname;
+        if (!map[key]) {
+            map[key] = { hostname: item.hostname, resolution_date: item.resolution_date || null, vertical: item.vertical };
+        } else {
+            // Keep the earliest non-null resolution_date
+            const existing = map[key];
+            if (item.resolution_date != null) {
+                if (existing.resolution_date == null || item.resolution_date < existing.resolution_date) {
+                    existing.resolution_date = item.resolution_date;
+                }
+            }
+        }
+    }
+    return Object.values(map);
+}
+
+/**
+ * Computes aggregated burndown from a deduplicated array of device objects.
+ * Each device has { hostname, resolution_date, vertical }.
+ *
+ * @param {Array<{ hostname: string, resolution_date: string|null, vertical: string }>} devices
+ * @returns {{
+ *   total: number,
+ *   blockers: number,
+ *   with_dates: number,
+ *   monthly: Object<string, number>,
+ *   projection: Object<string, { remediated: number, remaining: number }>,
+ *   projected_clear_date: string|null,
+ *   by_vertical: Array<{ vertical: string, total: number, blockers: number, with_dates: number }>
+ * }}
+ */
+function computeAggregatedBurndown(devices) {
+    const total = devices.length;
+    const withDates = devices.filter(d => d.resolution_date != null);
+    const blockerDevices = devices.filter(d => d.resolution_date == null);
+    const blockers = blockerDevices.length;
+    const with_dates = withDates.length;
+
+    // Bucket by month (YYYY-MM)
+    const monthly = {};
+    for (const device of withDates) {
+        const dateStr = typeof device.resolution_date === 'string'
+            ? device.resolution_date
+            : device.resolution_date.toISOString().slice(0, 10);
+        const month = dateStr.slice(0, 7);
+        monthly[month] = (monthly[month] || 0) + 1;
+    }
+
+    // Sort monthly keys chronologically
+    const sortedMonths = Object.keys(monthly).sort();
+    const sortedMonthly = {};
+    for (const m of sortedMonths) {
+        sortedMonthly[m] = monthly[m];
+    }
+
+    // Cumulative projection
+    let remaining = total;
+    const projection = {};
+    for (const month of sortedMonths) {
+        remaining -= sortedMonthly[month];
+        projection[month] = { remediated: sortedMonthly[month], remaining };
+    }
+
+    // Projected clear date
+    let projected_clear_date = null;
+    if (blockers === 0 && sortedMonths.length > 0) {
+        projected_clear_date = sortedMonths[sortedMonths.length - 1];
+    }
+
+    // Per-vertical breakdown
+    const verticalMap = {};
+    for (const device of devices) {
+        const v = device.vertical;
+        if (!verticalMap[v]) {
+            verticalMap[v] = { vertical: v, total: 0, blockers: 0, with_dates: 0 };
+        }
+        verticalMap[v].total++;
+        if (device.resolution_date == null) {
+            verticalMap[v].blockers++;
+        } else {
+            verticalMap[v].with_dates++;
+        }
+    }
+
+    // Sort descending by total, filter out zero-total entries
+    const by_vertical = Object.values(verticalMap)
+        .filter(v => v.total > 0)
+        .sort((a, b) => b.total - a.total);
+
+    return {
+        total,
+        blockers,
+        with_dates,
+        monthly: sortedMonthly,
+        projection,
+        projected_clear_date,
+        by_vertical,
+    };
+}
+
 module.exports = {
     truncateText,
     validateRemediationPlan,
@@ -292,4 +402,6 @@ module.exports = {
     mapColumnHeaders,
     parseVerticalFilename,
     computeVerticalBurndown,
+    deduplicateByHostname,
+    computeAggregatedBurndown,
 };