Replace unused server metrics with a count (Refs #139)

tests/unit/metrics.test.ts

@@ -79,7 +79,7 @@ describe('historical metrics', () => {
             expect(result.maps[0].matches).toEqual(result.matches);
             expect(result.maps[0].running).toEqual({ average: null, peak: 0, capturedHours: 0 });
             expect(result.registeredServerCount).toBe(0);
-            expect(result.servers).toEqual([]);
+            expect(result.sampledServerCount).toBe(0);
             expect(result.scopeOptions.maps).not.toContainEqual({ game: 't5', map: 'Future Map' });
         }
     );
@@ -304,7 +304,11 @@ describe('historical metrics', () => {
         const at = Date.UTC(2026, 0, 2);
         const sample = { server: 'removed', game: 't6', map: 'Town', players: 1, capacity: null };
         recordMetrics([sample], at);
-        expect(readMetrics(1, at + 30_000).servers[0].server).toBe('removed');
+        expect(readMetrics(1, at + 30_000)).toMatchObject({
+            sampledServerCount: 1,
+            registeredServerCount: 0,
+            maps: [{ game: 't6', map: 'Town', active: 30 / 3600 }]
+        });
         recordMetrics([sample], at + 32 * 86400_000);
         expect(db().prepare('SELECT COUNT(*) AS n FROM metric_samples').get()).toEqual({ n: 1 });
     });
@@ -318,7 +322,7 @@ describe('historical metrics', () => {
             firstRetainedSampleAt: null,
             latestSampleAt: null,
             registeredServerCount: 0,
-            servers: [],
+            sampledServerCount: 0,
             maps: []
         });
         db().prepare('INSERT INTO servers (name, destroyed_at) VALUES (?, ?)').run('current', null);
@@ -332,7 +336,7 @@ describe('historical metrics', () => {
             firstRetainedSampleAt: at,
             latestSampleAt: at,
             registeredServerCount: 1,
-            servers: [],
+            sampledServerCount: 0,
             maps: [],
             summary: { observed: 0, unknown: 0 }
         });
@@ -351,7 +355,7 @@ describe('historical metrics', () => {
         );
         const initial = readMetrics(1, at);
         expect(initial.latestSampleAt).toBe(at);
-        expect(initial.servers).toHaveLength(1);
+        expect(initial.sampledServerCount).toBe(1);
         expect(initial.summary).toEqual({
             observed: 0,
             active: 0,
@@ -404,9 +408,7 @@ describe('historical metrics', () => {
         expect(result.summary.active * 3600).toBeCloseTo(90);
         expect(result.summary.idle * 3600).toBeCloseTo(90);
         expect(result.summary.playerHours * 3600).toBeCloseTo(300);
-        expect(
-            result.servers.find((server) => server.server === 'two')!.observed * 3600
-        ).toBeCloseTo(30);
+        expect(result.sampledServerCount).toBe(2);
         const town = result.maps.find((map) => map.game === 't6' && map.map === 'Town')!;
         expect(town.observed * 3600).toBeCloseTo(60);
         expect(town.availabilityObserved * 3600).toBeCloseTo(30);
@@ -418,9 +420,6 @@ describe('historical metrics', () => {
             expect(result.points.reduce((sum, point) => sum + point[field], 0)).toBeCloseTo(
                 result.summary[field]
             );
-            expect(result.servers.reduce((sum, server) => sum + server[field], 0)).toBeCloseTo(
-                result.summary[field]
-            );
             expect(result.maps.reduce((sum, map) => sum + map[field], 0)).toBeCloseTo(
                 result.summary[field]
             );
@@ -436,6 +435,7 @@ describe('historical metrics', () => {
         recordMetrics([{ ...sample, players: 4 }], at + 60_000);
         const result = readMetrics(1, at + 30_000);
         expect(result.latestSampleAt).toBe(at);
+        expect(result.sampledServerCount).toBe(1);
         expect(result.summary.playerHours * 3600).toBeCloseTo(30);
     });
 
@@ -520,7 +520,7 @@ describe('historical metrics', () => {
         expect(result.summary.playerHours * 3600).toBeCloseTo(60);
         expect(result.previous.summary.active * 3600).toBeCloseTo(30);
         expect(result.previous.summary.playerHours * 3600).toBeCloseTo(120);
-        expect(result.servers.map((server) => server.server)).toEqual(['one']);
+        expect(result.sampledServerCount).toBe(1);
         expect(result.maps.map((map) => [map.game, map.map])).toEqual([['t5', 'Moon']]);
         expect(result.scopeOptions).toEqual({
             games: ['t5', 't6'],
@@ -557,7 +557,7 @@ describe('historical metrics', () => {
             scopeLatestSampleAt: null,
             summary: { observed: 0, unknown: 0 },
             maps: [],
-            servers: [],
+            sampledServerCount: 0,
             pooledAvailability: { value: null },
             running: { average: null, peak: 0, capturedHours: 0 },
             previous: { firstSampleAt: null, lastSampleAt: null, partialHistory: true }
@@ -598,6 +598,7 @@ describe('historical metrics', () => {
         recordMetrics([one, two], now - 30_000);
         const result = readMetrics(1, now);
         expect(result.running.average).toBeCloseTo(1.6);
+        expect(result.sampledServerCount).toBe(3);
         expect(result.running.peak).toBe(3);
         expect(result.running.capturedHours * 3600).toBeCloseTo(150);
         expect(result.maps[0].running).toEqual(result.running);
@@ -939,7 +940,7 @@ describe('historical metrics', () => {
         expect(result.heatmap.cells.filter((cell) => cell.observed > 0)).toHaveLength(1);
     });
 
-    it('counts unknown heatmap evidence and distinguishes retained names from current registrations', async () => {
+    it('counts unknown heatmap evidence and sampled names independently of current registrations', async () => {
         const { recordMetrics, readMetrics } =
             await import('../../src/lib/server/fleet/metrics.js');
         const { db } = await import('../../src/lib/server/db/index.js');
@@ -949,8 +950,7 @@ describe('historical metrics', () => {
             [sample, { ...sample, server: 'removed' }, { ...sample, server: 'tombstone' }],
             at
         );
-        // A newly registered name can link to the current server without asserting
-        // that its earlier historical observations belong to this registration.
+        // Current registration counts stay separate from sampled names, including reuse.
         db()
             .prepare('INSERT INTO servers (name, created_at) VALUES (?, ?)')
             .run('reused', new Date(at + 15_000).toISOString());
@@ -958,14 +958,9 @@ describe('historical metrics', () => {
             .prepare('INSERT INTO servers (name, destroyed_at) VALUES (?, ?)')
             .run('tombstone', new Date(at).toISOString());
         const result = readMetrics(1, at + 30_000);
-        expect(result.servers.find((server) => server.server === 'reused')!.currentRegistered).toBe(
-            true
-        );
-        expect(
-            result.servers
-                .filter((server) => server.server !== 'reused')
-                .every((server) => !server.currentRegistered)
-        ).toBe(true);
+        expect(result.sampledServerCount).toBe(3);
+        expect(result.registeredServerCount).toBe(1);
+        expect(result).not.toHaveProperty('servers');
         expect(
             result.heatmap.cells.reduce((sum, cell) => sum + cell.unknown, 0) * 3600
         ).toBeCloseTo(90);