Show match demand in metrics (Refs #138)

src/lib/server/reports/revisions.ts

@@ -1,5 +1,22 @@
 import type Database from 'better-sqlite3';
 
+/** Match demand includes active and interrupted matches, independent of leaderboard eligibility. */
+export function installMetricsMatchRevisions(handle: Database.Database) {
+    for (const table of ['leaderboard_matches', 'leaderboard_match_players'])
+        for (const action of ['INSERT', 'UPDATE', 'DELETE']) {
+            const fields =
+                table === 'leaderboard_matches' ? ['game', 'map_name', 'started_at'] : ['match_id'];
+            // Score/presence heartbeats do not change distinct participant counts.
+            const condition =
+                action === 'UPDATE'
+                    ? `WHEN ${fields.map((field) => `OLD.${field} IS NOT NEW.${field}`).join(' OR ')}`
+                    : '';
+            handle.exec(`CREATE TRIGGER IF NOT EXISTS report_metrics_${table}_${action}
+                AFTER ${action} ON ${table} ${condition}
+                BEGIN UPDATE report_revisions SET revision=revision+1 WHERE topic='metrics'; END;`);
+        }
+}
+
 /** Current policy settings are inputs to historical metrics advice. */
 export function installMetricsPolicyRevisions(handle: Database.Database) {
     for (const table of ['autoscaling_policies', 'settings'])