Add unique and new player metrics (Refs #142)

src/lib/server/fleet/metrics-players.ts

@@ -0,0 +1,87 @@
+import { db } from '../db/index.js';
+import type { MetricPoint, MetricsScope, PlayerMetrics } from '../../metrics.js';
+
+/** Populate the shared periods from retained participation, independently of occupancy samples. */
+export function readPlayerMetrics(
+    scope: MetricsScope,
+    since: number,
+    now: number,
+    points: MetricPoint[]
+): PlayerMetrics {
+    const handle = db();
+    const nowIso = new Date(now).toISOString();
+    const sinceIso = new Date(since).toISOString();
+    const { first } = handle
+        .prepare('SELECT MIN(started_at) AS first FROM leaderboard_matches WHERE started_at <= ?')
+        .get(nowIso) as { first: string | null };
+    const historyStartAt = first === null ? null : Date.parse(first);
+    const periods = points.map((point) => {
+        const available =
+            historyStartAt !== null &&
+            (historyStartAt < point.endAt || (historyStartAt === now && point.endAt === now));
+        point.uniquePlayers = available ? 0 : null;
+        point.newPlayers = available ? 0 : null;
+        point.playerHistoryPartial = available && historyStartAt! > point.startAt;
+        return { unique: new Set<string>(), fresh: new Set<string>() };
+    });
+    if (historyStartAt === null) return { historyStartAt, uniquePlayers: null, newPlayers: null };
+
+    const conditions = [
+        'm.last_received_at >= ?',
+        'm.started_at <= ?',
+        'p.last_seen_at >= ?',
+        'p.first_seen_at <= ?'
+    ];
+    const params = [sinceIso, nowIso, sinceIso, nowIso];
+    if (scope.game !== null) {
+        conditions.push('m.game = ?');
+        params.push(scope.game);
+    }
+    if (scope.map !== null) {
+        conditions.push('m.map_name = ?');
+        params.push(scope.map);
+    }
+    // The match clock and participation PK bound this scan to recent matches.
+    // The GUID/first-seen index looks up the durable cross-game identity without
+    // reclassifying a returning player after their older matches expire.
+    const rows = handle
+        .prepare(
+            `SELECT p.guid, p.first_seen_at AS start, p.last_seen_at AS end,
+            (SELECT MIN(first_seen_at) FROM leaderboard_players WHERE guid=p.guid) AS firstSeen
+        FROM leaderboard_matches m JOIN leaderboard_match_players p ON p.match_id=m.id
+        WHERE ${conditions.join(' AND ')}`
+        )
+        .iterate(...params) as Iterable<{
+        guid: string;
+        start: string;
+        end: string;
+        firstSeen: string | null;
+    }>;
+    const unique = new Set<string>();
+    const fresh = new Set<string>();
+    for (const row of rows) {
+        const start = Date.parse(row.start);
+        const end = Date.parse(row.end);
+        if (!Number.isFinite(start) || !Number.isFinite(end) || end < start) continue;
+        unique.add(row.guid);
+        // Scope the original sighting, never the first later visit to this game/map.
+        const isNew =
+            row.firstSeen !== null && Date.parse(row.firstSeen) === start && start >= since;
+        if (isNew) fresh.add(row.guid);
+        for (let index = 0; index < points.length; index++) {
+            const point = points[index];
+            // Internal boundaries belong to the next period. Include a sighting
+            // exactly at the report's inclusive right edge in its final period.
+            const startsBeforeEnd = start < point.endAt || (start === now && point.endAt === now);
+            if (point.uniquePlayers === null || end < point.startAt || !startsBeforeEnd) continue;
+            periods[index].unique.add(row.guid);
+            if (isNew && start >= point.startAt) periods[index].fresh.add(row.guid);
+        }
+    }
+    for (let index = 0; index < points.length; index++) {
+        if (points[index].uniquePlayers === null) continue;
+        points[index].uniquePlayers = periods[index].unique.size;
+        points[index].newPlayers = periods[index].fresh.size;
+    }
+    return { historyStartAt, uniquePlayers: unique.size, newPlayers: fresh.size };
+}