feat: privacy-respecting analytics

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/app.ts

@@ -12,6 +12,7 @@ import { betsRouter } from './routes/bets.js'
 import { paymentsRouter } from './routes/payments.js'
 import { tournamentsRouter } from './routes/tournaments.js'
 import { adminRouter } from './routes/admin.js'
+import { statsRouter } from './routes/stats.js'
 import { rateLimit } from './middleware/rate-limit.js'
 
 import { existsSync, readFileSync } from 'fs'
@@ -62,6 +63,7 @@ app.route('/api/bets', betsRouter)
 app.route('/api/payments', paymentsRouter)
 app.route('/api/tournaments', tournamentsRouter)
 app.route('/api/admin', adminRouter)
+app.route('/api/stats', statsRouter)
 
 // In production, serve the frontend SPA
 const __dirname = dirname(fileURLToPath(import.meta.url))

server/src/db/schema.ts

@@ -134,6 +134,12 @@ export const tournamentEntries = sqliteTable('tournament_entries', {
   createdAt: text('created_at').notNull(),
 })
 
+export const analytics = sqliteTable('analytics', {
+  date: text('date').notNull(),
+  metric: text('metric').notNull(),
+  value: integer('value').notNull().default(0),
+})
+
 export const tournamentMatches = sqliteTable('tournament_matches', {
   id: text('id').primaryKey(),
   tournamentId: text('tournament_id').notNull().references(() => tournaments.id),

server/src/db/startup.ts

@@ -126,6 +126,15 @@ export function runMigrations() {
     );
   `)
 
+  sqlite.exec(`
+    CREATE TABLE IF NOT EXISTS analytics (
+      date TEXT NOT NULL,
+      metric TEXT NOT NULL,
+      value INTEGER NOT NULL DEFAULT 0
+    );
+    CREATE UNIQUE INDEX IF NOT EXISTS idx_analytics_date_metric ON analytics(date, metric);
+  `)
+
   // Column migrations for existing databases
   const migrations = [
     "ALTER TABLE bots ADD COLUMN archetype TEXT NOT NULL DEFAULT 'standard'",

server/src/engine/analytics.ts

@@ -0,0 +1,67 @@
+import { sqlite } from '../db/index.js'
+
+function today(): string {
+  return new Date().toISOString().slice(0, 10)
+}
+
+const incrementStmt = sqlite.prepare(
+  `INSERT INTO analytics (date, metric, value) VALUES (?, ?, 1)
+   ON CONFLICT(date, metric) DO UPDATE SET value = value + 1`
+)
+
+const incrementByStmt = sqlite.prepare(
+  `INSERT INTO analytics (date, metric, value) VALUES (?, ?, ?)
+   ON CONFLICT(date, metric) DO UPDATE SET value = value + ?`
+)
+
+/** Increment a metric counter for today */
+export function trackMetric(metric: string): void {
+  try { incrementStmt.run(today(), metric) } catch { /* best-effort */ }
+}
+
+/** Increment a metric by a specific amount */
+export function trackMetricBy(metric: string, amount: number): void {
+  try { incrementByStmt.run(today(), metric, amount, amount) } catch { /* best-effort */ }
+}
+
+/** Record a fight completion with aggregate counters */
+export function trackFightCompleted(opts: {
+  satsWagered: number
+  durationRounds: number
+  mode: 'free' | 'ranked'
+}): void {
+  trackMetric('fights')
+  trackMetric(`fights_${opts.mode}`)
+  if (opts.satsWagered > 0) {
+    trackMetricBy('sats_wagered', opts.satsWagered)
+  }
+  trackMetricBy('total_rounds', opts.durationRounds)
+}
+
+/** Track a unique bot that fought today */
+export function trackBotActive(botId: string): void {
+  const key = `${today()}:${botId}`
+  if (seenBots.has(key)) return
+  seenBots.add(key)
+  trackMetric('unique_bots')
+
+  // Prune old entries (keep only today's)
+  const todayPrefix = today() + ':'
+  for (const k of seenBots) {
+    if (!k.startsWith(todayPrefix)) seenBots.delete(k)
+  }
+}
+
+const seenBots = new Set<string>()
+
+/** Get aggregate stats for the last N days */
+export function getPublicStats(days: number = 30): Array<{ date: string; metric: string; value: number }> {
+  const cutoff = new Date()
+  cutoff.setDate(cutoff.getDate() - days)
+  const cutoffStr = cutoff.toISOString().slice(0, 10)
+
+  const stmt = sqlite.prepare(
+    'SELECT date, metric, value FROM analytics WHERE date >= ? ORDER BY date DESC, metric'
+  )
+  return stmt.all(cutoffStr) as Array<{ date: string; metric: string; value: number }>
+}

server/src/engine/orchestrator.ts

@@ -15,6 +15,7 @@ import { settleBets, lockBets } from './betting.js'
 import { publishFightResult } from './nostr-publish.js'
 import { getCurrentSeason } from './seasons.js'
 import { onFightFinished as onTournamentFightFinished } from './tournaments.js'
+import { trackFightCompleted, trackBotActive, trackMetric } from './analytics.js'
 
 interface BotRecord {
   id: string
@@ -514,6 +515,18 @@ async function executeFightRounds(fightId: string, botA: BotRecord, botB: BotRec
 
   finalize()
 
+  // Track aggregate analytics (no PII)
+  trackBotActive(botA.id)
+  trackBotActive(botB.id)
+  trackFightCompleted({
+    satsWagered: mode === 'ranked' ? ENTRY_FEE_SATS * 2 : 0,
+    durationRounds: lastRound,
+    mode,
+  })
+  for (const ct of usedTypes) {
+    trackMetric(`challenge_${ct}`)
+  }
+
   // Advance tournament bracket if this was a tournament match
   try { onTournamentFightFinished(fightId, winnerId ?? null) } catch { /* not a tournament fight */ }
 

server/src/routes/stats.ts

@@ -0,0 +1,19 @@
+import { Hono } from 'hono'
+import { getPublicStats } from '../engine/analytics.js'
+
+export const statsRouter = new Hono()
+
+// GET /public — aggregate stats for last 30 days, no PII
+statsRouter.get('/public', (c) => {
+  const days = Math.min(parseInt(c.req.query('days') || '30'), 90)
+  const rows = getPublicStats(days)
+
+  // Group by date for easier consumption
+  const byDate: Record<string, Record<string, number>> = {}
+  for (const row of rows) {
+    if (!byDate[row.date]) byDate[row.date] = {}
+    byDate[row.date][row.metric] = row.value
+  }
+
+  return c.json({ stats: byDate })
+})