perf(practice): eliminate redundant getViewerId and user lookups

Refactor getPlayersWithSkillData() to return viewerId and userId
along with players, avoiding 2 redundant calls in Practice page:
- Previous: 3 calls to getViewer() (via getViewerId) + 2 user lookups
- Now: 1 call to getViewer() + 1 user lookup

This should reduce Practice page SSR time by eliminating duplicate
auth checks and database queries.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/src/app/api/players/with-skill-data/route.ts

@@ -8,8 +8,8 @@ import { getPlayersWithSkillData } from '@/lib/curriculum/server'
  */
 export async function GET() {
   try {
-    const players = await getPlayersWithSkillData()
-    return NextResponse.json({ players })
+    const result = await getPlayersWithSkillData()
+    return NextResponse.json({ players: result.players })
   } catch (error) {
     console.error('Failed to fetch players with skill data:', error)
     return NextResponse.json({ error: 'Failed to fetch players' }, { status: 500 })

apps/web/src/app/practice/page.tsx

@@ -1,25 +1,6 @@
-import { eq } from 'drizzle-orm'
-import { db, schema } from '@/db'
 import { getPlayersWithSkillData } from '@/lib/curriculum/server'
-import { getViewerId } from '@/lib/viewer'
 import { PracticeClient } from './PracticeClient'
 
-/**
- * Get or create user record for a viewerId (guestId)
- */
-async function getOrCreateUser(viewerId: string) {
-  let user = await db.query.users.findFirst({
-    where: eq(schema.users.guestId, viewerId),
-  })
-
-  if (!user) {
-    const [newUser] = await db.insert(schema.users).values({ guestId: viewerId }).returning()
-    user = newUser
-  }
-
-  return user
-}
-
 /**
  * Practice page - Server Component
  *
@@ -30,13 +11,8 @@ async function getOrCreateUser(viewerId: string) {
  */
 export default async function PracticePage() {
   // Fetch players with skill data directly on server - no HTTP round-trip
-  const players = await getPlayersWithSkillData()
+  // Returns players, viewerId, and userId in a single call to avoid redundant lookups
+  const { players, viewerId, userId } = await getPlayersWithSkillData()
 
-  // Get viewer ID for session observation
-  const viewerId = await getViewerId()
-
-  // Get database user ID for parent socket notifications
-  const user = await getOrCreateUser(viewerId)
-
-  return <PracticeClient initialPlayers={players} viewerId={viewerId} userId={user.id} />
+  return <PracticeClient initialPlayers={players} viewerId={viewerId} userId={userId} />
 }

apps/web/src/lib/curriculum/server.ts

@@ -88,6 +88,15 @@ export async function getPlayersForViewer(): Promise<Player[]> {
   return players
 }
 
+/**
+ * Result from getPlayersWithSkillData including context for page rendering
+ */
+export interface PlayersWithSkillDataResult {
+  players: StudentWithSkillData[]
+  viewerId: string
+  userId: string
+}
+
 /**
  * Get all players for the current viewer with enhanced skill data.
  *
@@ -97,11 +106,13 @@ export async function getPlayersForViewer(): Promise<Player[]> {
  * - skillCategory: Computed highest-level skill category
  * - intervention: Intervention data if student needs attention
  *
+ * Also returns viewerId and userId to avoid redundant calls in page components.
+ *
  * Performance: Uses batched queries to avoid N+1 query patterns.
  * - Single query for all skill mastery records across all players
- * - Single query for session history across all players needing intervention
+ * - Returns viewerId/userId to avoid redundant getViewerId() calls
  */
-export async function getPlayersWithSkillData(): Promise<StudentWithSkillData[]> {
+export async function getPlayersWithSkillData(): Promise<PlayersWithSkillDataResult> {
   const viewerId = await getViewerId()
 
   // Get or create user record
@@ -114,6 +125,8 @@ export async function getPlayersWithSkillData(): Promise<StudentWithSkillData[]>
     user = newUser
   }
 
+  const userId = user.id
+
   // Get player IDs linked via parent_child table
   const linkedPlayerIds = await db.query.parentChild.findMany({
     where: eq(parentChild.parentUserId, user.id),
@@ -135,7 +148,7 @@ export async function getPlayersWithSkillData(): Promise<StudentWithSkillData[]>
   }
 
   if (players.length === 0) {
-    return []
+    return { players: [], viewerId, userId }
   }
 
   // OPTIMIZATION: Batch query all skill mastery records for all players at once
@@ -186,7 +199,7 @@ export async function getPlayersWithSkillData(): Promise<StudentWithSkillData[]>
   // Intervention badges are helpful but not critical for initial render.
   // They can be computed lazily on the client if needed.
   // This avoids N additional database queries for session history.
-  return playersWithBasicSkills
+  return { players: playersWithBasicSkills, viewerId, userId }
 }
 
 // Re-export the individual functions for granular prefetching