fix: pre-compute stats to make the API endpoint fast

frontend/server/api/stats.ts

@@ -1,14 +1,29 @@
 import type { MongoClient } from 'mongodb'
 import { connectToDatabase, fetchLatestPatch, getAvailablePlatforms } from '../utils/mongo'
 
+interface StatsDocument {
+  patch: string
+  total: number
+  platforms: Record<string, number>
+  updatedAt: Date
+}
+
 async function fetchGameCount(client: MongoClient, patch: string) {
   const database = client.db('matches')
+  const statsCollection = database.collection<StatsDocument>('stats')
 
-  // Check for platform-specific collections
+  // Try to get stats from the pre-computed stats collection
+  const stats = await statsCollection.findOne({ patch })
+
+  if (stats) {
+    return { total: stats.total, platforms: stats.platforms }
+  }
+
+  // Fallback: compute stats from collections if stats document doesn't exist
+  // This handles the migration case where stats weren't pre-computed
   const platforms = await getAvailablePlatforms(client, patch)
 
   if (platforms.length > 0) {
-    // Sum counts from all platform-specific collections
     let totalCount = 0
     const platformCounts: Record<string, number> = {}
 

match_collector/src/index.ts

@@ -4,6 +4,7 @@ const sleep_minutes = 12
 import { MongoClient } from 'mongodb'
 
 import champion_stat from './champion_stat'
+import stats from './stats'
 import { Match } from './api'
 import { PLATFORMS, getPlatformBaseUrl, getRegionalBaseUrl, getRegionForPlatform } from './platform'
 import { downloadCDragonAssets } from './cdragon_cache'
@@ -98,6 +99,9 @@ async function cleanupOldPatches(client: MongoClient, keepPatches: number): Prom
     }
   }
 
+  // Delete stats for removed patches
+  await stats.deleteStats(client, patchesToRemove)
+
   console.log(`Cleanup: Dropped ${droppedCount} collection(s).`)
 }
 
@@ -300,6 +304,9 @@ async function saveMatch(client: MongoClient, match: Match, patch: string, platf
   const collectionName = `${patch}_${platform}`
   const matches = database.collection(collectionName)
   await matches.insertOne(match)
+
+  // Increment stats counter for this patch/platform
+  await stats.incrementMatchCount(client, patch, platform)
 }
 
 /**
@@ -348,6 +355,11 @@ async function runWithPreloadedData() {
       .filter(name => name.startsWith(`${latestPatch}_`))
       .map(name => name.replace(`${latestPatch}_`, ''))
 
+    // Recalculate match count stats from existing collections
+    if (platforms.length > 0) {
+      await stats.recalculateStats(client, latestPatch, platforms)
+    }
+
     // Generate stats for each platform
     if (platforms.length > 0) {
       await champion_stat.makeChampionsStats(client, latestPatch, platforms)

match_collector/src/stats.ts

@@ -0,0 +1,152 @@
+import { MongoClient } from 'mongodb'
+
+/**
+ * Stats document structure stored in the 'stats' collection.
+ * One document per patch, containing total and per-platform match counts.
+ */
+interface StatsDocument {
+  patch: string
+  total: number
+  platforms: Record<string, number>
+  updatedAt: Date
+}
+
+const STATS_COLLECTION = 'stats'
+const STATS_DATABASE = 'matches'
+
+/**
+ * Initialize stats document for a patch if it doesn't exist.
+ * This should be called before processing matches for a new patch.
+ */
+async function initStats(client: MongoClient, patch: string): Promise<void> {
+  const database = client.db(STATS_DATABASE)
+  const collection = database.collection<StatsDocument>(STATS_COLLECTION)
+
+  await collection.updateOne(
+    { patch },
+    {
+      $setOnInsert: {
+        patch,
+        total: 0,
+        platforms: {},
+        updatedAt: new Date()
+      }
+    },
+    { upsert: true }
+  )
+}
+
+/**
+ * Increment match count for a specific patch and platform.
+ * This should be called each time a new match is saved.
+ */
+async function incrementMatchCount(
+  client: MongoClient,
+  patch: string,
+  platform: string
+): Promise<void> {
+  const database = client.db(STATS_DATABASE)
+  const collection = database.collection<StatsDocument>(STATS_COLLECTION)
+
+  await collection.updateOne(
+    { patch },
+    {
+      $inc: { total: 1, [`platforms.${platform}`]: 1 },
+      $set: { updatedAt: new Date() }
+    },
+    { upsert: true }
+  )
+}
+
+/**
+ * Get stats for a specific patch.
+ * Returns null if no stats exist for the patch.
+ */
+async function getStats(client: MongoClient, patch: string): Promise<StatsDocument | null> {
+  const database = client.db(STATS_DATABASE)
+  const collection = database.collection<StatsDocument>(STATS_COLLECTION)
+
+  return await collection.findOne({ patch })
+}
+
+/**
+ * Get stats for all patches, sorted from latest to oldest.
+ */
+async function getAllStats(client: MongoClient): Promise<StatsDocument[]> {
+  const database = client.db(STATS_DATABASE)
+  const collection = database.collection<StatsDocument>(STATS_COLLECTION)
+
+  const stats = await collection.find({}).toArray()
+
+  // Sort patches from latest to oldest
+  return stats.sort((a, b) => {
+    const [aMajor, aMinor] = a.patch.split('.').map(Number)
+    const [bMajor, bMinor] = b.patch.split('.').map(Number)
+    if (aMajor !== bMajor) return bMajor - aMajor
+    return bMinor - aMinor
+  })
+}
+
+/**
+ * Delete stats for patches that are being cleaned up.
+ * This should be called when old patch collections are dropped.
+ */
+async function deleteStats(client: MongoClient, patches: string[]): Promise<void> {
+  if (patches.length === 0) return
+
+  const database = client.db(STATS_DATABASE)
+  const collection = database.collection<StatsDocument>(STATS_COLLECTION)
+
+  await collection.deleteMany({ patch: { $in: patches } })
+  console.log(`Stats: Deleted stats for patches: ${patches.join(', ')}`)
+}
+
+/**
+ * Recalculate stats from existing match collections.
+ * This is useful for migration or fixing inconsistent stats.
+ */
+async function recalculateStats(
+  client: MongoClient,
+  patch: string,
+  platforms: string[]
+): Promise<void> {
+  const database = client.db(STATS_DATABASE)
+
+  let total = 0
+  const platformCounts: Record<string, number> = {}
+
+  for (const platform of platforms) {
+    const collectionName = `${patch}_${platform}`
+    const collection = database.collection(collectionName)
+    const count = await collection.countDocuments()
+    platformCounts[platform] = count
+    total += count
+  }
+
+  const statsCollection = database.collection<StatsDocument>(STATS_COLLECTION)
+  await statsCollection.updateOne(
+    { patch },
+    {
+      $set: {
+        patch,
+        total,
+        platforms: platformCounts,
+        updatedAt: new Date()
+      }
+    },
+    { upsert: true }
+  )
+
+  console.log(`Stats: Recalculated stats for patch ${patch}: ${total} total matches`)
+}
+
+export default {
+  initStats,
+  incrementMatchCount,
+  getStats,
+  getAllStats,
+  deleteStats,
+  recalculateStats
+}
+
+export type { StatsDocument }