feat(metrics): add bucket series merge and container ranking

app/Services/FleetMetricsAggregator.php

@@ -61,6 +61,50 @@ class FleetMetricsAggregator
         ];
     }
 
+    /**
+     * @param  array<int, array<int, array{0: int, 1: float}>>  $seriesPerServer
+     * @return array<int, array{0: int, 1: float}>
+     */
+    public static function sumSeriesByBucket(array $seriesPerServer, string $mode): array
+    {
+        $totals = [];
+        $counts = [];
+
+        foreach ($seriesPerServer as $series) {
+            foreach ($series as [$ts, $value]) {
+                $totals[$ts] = ($totals[$ts] ?? 0.0) + (float) $value;
+                $counts[$ts] = ($counts[$ts] ?? 0) + 1;
+            }
+        }
+
+        ksort($totals);
+
+        $out = [];
+        foreach ($totals as $ts => $sum) {
+            $out[] = [(int) $ts, $mode === 'avg' ? round($sum / $counts[$ts], 2) : round($sum, 2)];
+        }
+
+        return $out;
+    }
+
+    /**
+     * @param  array<int, array<string, mixed>>  $containers
+     * @return array<int, array<string, mixed>>
+     */
+    public static function rankContainers(array $containers, string $metric, int $limit = 20): array
+    {
+        $key = match ($metric) {
+            'memory' => 'memUsed',
+            'disk' => 'diskBytes',
+            'network' => 'net',
+            default => 'cpu',
+        };
+
+        usort($containers, fn ($a, $b) => ($b[$key] ?? 0) <=> ($a[$key] ?? 0));
+
+        return array_slice($containers, 0, $limit);
+    }
+
     /**
      * @param  array<int, array<string, mixed>>  $rows
      * @return array<int, float>

tests/Unit/Services/FleetMetricsAggregatorRankingTest.php

@@ -0,0 +1,33 @@
+<?php
+
+use App\Services\FleetMetricsAggregator;
+
+it('sums series by bucket timestamp and sorts ascending', function () {
+    $merged = FleetMetricsAggregator::sumSeriesByBucket([
+        [[2000, 5.0], [1000, 1.0]],
+        [[1000, 2.0], [3000, 9.0]],
+    ], 'sum');
+
+    expect($merged)->toBe([[1000, 3.0], [2000, 5.0], [3000, 9.0]]);
+});
+
+it('averages series across servers per bucket', function () {
+    $merged = FleetMetricsAggregator::sumSeriesByBucket([
+        [[1000, 20.0]],
+        [[1000, 40.0]],
+    ], 'avg');
+
+    expect($merged)->toBe([[1000, 30.0]]);
+});
+
+it('ranks containers by the selected metric and caps the list', function () {
+    $containers = [
+        ['id' => 'a', 'cpu' => 10.0, 'memUsed' => 500, 'diskBytes' => 5, 'net' => 1.0],
+        ['id' => 'b', 'cpu' => 90.0, 'memUsed' => 100, 'diskBytes' => 9, 'net' => 2.0],
+        ['id' => 'c', 'cpu' => 50.0, 'memUsed' => 900, 'diskBytes' => 1, 'net' => 3.0],
+    ];
+
+    expect(array_column(FleetMetricsAggregator::rankContainers($containers, 'cpu', 2), 'id'))->toBe(['b', 'c']);
+    expect(array_column(FleetMetricsAggregator::rankContainers($containers, 'memory'), 'id'))->toBe(['c', 'a', 'b']);
+    expect(array_column(FleetMetricsAggregator::rankContainers($containers, 'network'), 'id'))->toBe(['c', 'b', 'a']);
+});