Implement the following plan:

Flashcard System for Learning Student Names

Context

The roster page (/roster) shows student photos in a grid. To help learn student names, we're adding a flashcard game at /roster/flashcards, launched via a button on the roster page. The game shows a student photo, the user tries to recall the name, reveals it, and marks correct/incorrect. A Leitner box spaced repetition system ensures missed students appear more frequently.

Files to Create

1. apps/web/app/roster/flashcards/leitner.ts — Spaced repetition algorithm

Pure TypeScript module, no React. Leitner box system:

• 4 boxes with weighted random selection (box 1: 8x, box 2: 4x, box 3: 2x, box 4: 1x)
• All cards start in box 1
• Correct → move up one box (max 4)
• Incorrect → back to box 1
• Session complete when all cards reach box 4
• Exports: initializeState, selectNextCard, markCorrect, markIncorrect, isSessionComplete, getBoxCounts
• Includes same-card avoidance (retry loop to prevent showing same student twice in a row)

2. apps/web/app/roster/flashcards/page.tsx — Server component

Follows exact pattern of existing roster page:

• Auth check via auth.api.getSession(), redirect to login if unauthenticated
• Fetch data via serverApiFetch<RosterResponse>("/api/admin/roster")
• Filter to students with hasPhoto: true and non-null name
• Build photo URLs using process.env.API_URL
• Pass filtered students to FlashcardsClient
• Show empty state if no students have photos

3. apps/web/app/roster/flashcards/client.tsx — Client component (game UI)

Interactive flashcard game with:

• Card display: Large photo (h-48 w-48 rounded-full) with CSS 3D flip animation to reveal name
• Scoring buttons: "Missed" (red) and "Got it" (green) after reveal
• Progress bar: Segmented bar showing card counts per Leitner box (color-coded)
• Keyboard shortcuts: Space/Enter to reveal, ArrowRight/Enter for correct, ArrowLeft/Backspace for incorrect
• Photo preloading: Preload next 2-3 photos with hidden <img> tags
• Completion screen: Shows stats (total reviews, accuracy, time) with "Play Again" and "Back to Roster" buttons
• Back link: Always-visible link back to /roster
• Uses existing Button component, cn() utility, lucide-react icons

4. testing/e2e/tests/flashcards.spec.ts — E2E tests

Tests:

• Unauthenticated user redirected to login
• Student sees empty/no-permission state
• Instructor can access the page (shows empty state since test users have no photos)
• "Practice Names" button exists on roster page for instructors

5. Update testing/e2e/playwright.config.ts

Add flashcards test project matching /flashcards\.spec\.ts/.

Files to Modify

6. apps/web/app/roster/page.tsx — Add launch button

Add a "Practice Names" link/button in the header area, next to the student count. Only shown if any students have photos. Uses Link from next/link and existing Button component with outline variant.

7. apps/web/styles/globals.css — Card flip animation

Add after existing animations (~line 180):

• .flashcard-perspective with perspective: 1000px
• .flashcard-inner with transform-style: preserve-3d and 0.5s transition
• .flashcard-inner.flipped with transform: rotateY(180deg)
• .flashcard-face with backface-visibility: hidden
• .flashcard-back with transform: rotateY(180deg)

No API Changes Needed

The existing /api/admin/roster endpoint and /api/admin/roster/photo/:uin endpoint provide all needed data.

Implementation Order

1. Leitner algorithm module (no deps)
2. CSS animations in globals.css
3. Server page (flashcards/page.tsx)
4. Client component (flashcards/client.tsx)
5. Roster page button modification
6. E2E tests + playwright config

Verification

1. Start dev server (check if already running first)
2. Navigate to /roster as instructor — verify "Practice Names" button appears
3. Click button — verify flashcard game loads with student photos
4. Test the flow: see photo → reveal name → mark correct/incorrect
5. Verify missed students reappear more frequently
6. Complete a session (all cards to box 4) — verify completion screen
7. Test keyboard shortcuts (Space, Enter, Arrow keys)
8. Run E2E tests: CI=true cd testing/e2e && bunx playwright test --project=flashcards
9. Run type checking: bun run tsc

If you need specific details from before exiting plan mode (like exact code snippets, error messages, or content you generated), read the full transcript at: ~/.claude/projects/-Users-challen-www-usingandunderstanding-ai/5a6412ba-9970-44b4-9f45-a964097d06d5.jsonl

OK cool! A few notes. There's a brief moment when the card is turning where I can see the name of the next student, which isn't good. Can we make the faces not change size when the name is revealed? Other than that it's awesome! I love the keyboard integration.

Now there's a hard transition between faces after the card rotates back. Can you use the face on the front but just not show the name until after the animation finishes and it's hidden?

Nope, still broken. Now the name fades out but is visible for a second. Step back and redesign this. It should not be that hard. The flip animation was nice.

Nope, the name is STILL VISIBLE as the card rotates! Why is this so hard? Just make the name not visible! I'm confused why you're struggling with this.

Sigh. Now what's the point of the flip? Here's what I wanted. Flip the card and, as it flips, fade in the name, which should be on the card. If the name is not on the card then there's no reason to flip! Then it's just annoying.

OK, let's just drop the flip. It's anonying. Just fade in the name on the card.

Your task

First, run git status, git diff, and git log --oneline -10 to understand the current state.

Then add and commit all modified files with a descriptive message. Break the changes into multiple commits if appropriate. If there are untracked files, ask if they should be added or added to the appropriate .gitignore file. The user may also want to take over at this point, so provide an abort option as well. Always check changes for unnecessary debugging statements or logging that might have been accidentally included. Prompt the user if you find any, and offer to remove each one by one. Do not use interactive git staging (git add -p) as it does not work.

Your task

First, run git status, git diff, and git log --oneline -10 to understand the current state.

Then add and commit all modified files with a descriptive message. Break the changes into multiple commits if appropriate. If there are untracked files, ask if they should be added or added to the appropriate .gitignore file. The user may also want to take over at this point, so provide an abort option as well. Always check changes for unnecessary debugging statements or logging that might have been accidentally included. Prompt the user if you find any, and offer to remove each one by one. Do not use interactive git staging (git add -p) as it does not work.

Please run bun check and fix the error.

Your task

First, run git status, git diff, and git log --oneline -10 to understand the current state.

Then add and commit all modified files with a descriptive message. Break the changes into multiple commits if appropriate. If there are untracked files, ask if they should be added or added to the appropriate .gitignore file. The user may also want to take over at this point, so provide an abort option as well. Always check changes for unnecessary debugging statements or logging that might have been accidentally included. Prompt the user if you find any, and offer to remove each one by one. Do not use interactive git staging (git add -p) as it does not work.

Let's rename the /instructors route to /educators and also use that term on that page: "For Educators" and etc.

Your task

First, run git status, git diff, and git log --oneline -10 to understand the current state.

Then add and commit all modified files with a descriptive message. Break the changes into multiple commits if appropriate. If there are untracked files, ask if they should be added or added to the appropriate .gitignore file. The user may also want to take over at this point, so provide an abort option as well. Always check changes for unnecessary debugging statements or logging that might have been accidentally included. Prompt the user if you find any, and offer to remove each one by one. Do not use interactive git staging (git add -p) as it does not work.

Your task

First, run git status, git diff, and git log --oneline -10 to understand the current state.

Then add and commit all modified files with a descriptive message. Break the changes into multiple commits if appropriate. If there are untracked files, ask if they should be added or added to the appropriate .gitignore file. The user may also want to take over at this point, so provide an abort option as well. Always check changes for unnecessary debugging statements or logging that might have been accidentally included. Prompt the user if you find any, and offer to remove each one by one. Do not use interactive git staging (git add -p) as it does not work.

OK! Now, I'd like to add more group awareness to the instructor activity page. For each group segment, as groups are formed, please use the photos to indicate who is working with who. Names can be on hover.

This session is being continued from a previous conversation that ran out of context. The summary below covers the earlier portion of the conversation.

Analysis: Let me go through the conversation chronologically to capture all important details.

1. Initial task: User asked to implement a flashcard system for learning student names at /roster/flashcards. A detailed plan was provided.

2. Implementation phase: I created multiple files:

   • apps/web/app/roster/flashcards/leitner.ts - Spaced repetition algorithm
   • apps/web/app/roster/flashcards/page.tsx - Server component
   • apps/web/app/roster/flashcards/client.tsx - Client component with game UI
   • testing/e2e/tests/flashcards.spec.ts - E2E tests
   • Modified apps/web/app/roster/page.tsx - Added "Practice Names" button
   • Modified apps/web/styles/globals.css - Added flip CSS
   • Modified testing/e2e/playwright.config.ts - Added flashcards project

3. TypeScript errors: The Record<number, string[]> type had possibly-undefined indexing. Fixed by creating a proper Boxes interface with explicit keys 1-4.

4. E2E test failure: Instructor test expected empty state but real roster had students with photos. Fixed by using .or() to check for either game or empty state.

5. User feedback #1: "brief moment when the card is turning where I can see the name of the next student" and "faces not change size when revealed". Fixed by:

   • Adding 500ms delay before swapping student (flip back first, then swap)
   • Making both faces use h-48 w-48 for photos
   • Increased card height to h-80
   • Added transitioning guard to prevent double-clicks

6. User feedback #2: "hard transition between faces after the card rotates back". User wanted to use the front face but not show the name until hidden. I removed the flip entirely and just faded the name in. Removed flip CSS.

7. User feedback #3: "Nope, still broken. Now the name fades out but is visible for a second." User wanted the flip back. I redesigned with:

   • Flip for reveal (front=photo, back=photo+name)
   • Name on back face starts at opacity:0, fades in after flip completes via nameVisible state
   • Fade out/in for card transitions between students
   • Added flip CSS back

8. Hydration error: Math.random() in selectNextCard during useState init caused server/client mismatch. Fixed by using students[0]!.email as deterministic first card.

9. User feedback #4: "Now what's the point of the flip? ... just not show the name until after the animation finishes and it's hidden?" I moved the name OFF the card to a separate element below, keeping flip purely decorative.

10. User feedback #5: "the name is STILL VISIBLE as the card rotates!" - The name was on the back face and visible through the rotation despite CSS backface-visibility. I moved the name to be separate from the card entirely, fading in after flip completes.

11. User feedback #6: "OK, let's just drop the flip. It's annoying. Just fade in the name on the card." I removed all flip animation, made it a simple card with photo + name that fades in. Removed flip CSS again. Removed flipped state, simplified to just nameVisible.

12. First commit: All flashcard files committed.

13. Lint errors from bun run check:

    • Date.now() called during render (react-hooks/purity) - Fixed by capturing endTime in state
    • @next/next/no-img-element eslint-disable comments for non-existent rule - Removed them
    • useRef accessed during render (react-hooks/refs) for studentMap and preloadEmails - Converted to useMemo
    • Removed unused previousEmailRef and useRef import

14. Second commit: Lint fixes committed.

15. Rename /instructors to /educators:

    • Renamed apps/web/app/instructors/ → apps/web/app/educators/
    • Renamed content/instructors.mdx → content/educators.mdx
    • Updated metadata, testids, heading
    • Updated E2E tests
    • Committed.

16. Version bump: All 23 package.json files bumped to 2026.2.16. Committed.

17. Current task: User entered plan mode asking to "add more group awareness to the instructor activity page. For each group segment, as groups are formed, please use the photos to indicate who is working with who. Names can be on hover."

18. I explored the codebase extensively, reading the admin group activities API, activity stage instructor controls component, and admin activity stages API. I was in the middle of Phase 1/2 of plan mode when the summary was requested.

Key files for the current task:

• apps/web/components/mdx/activity-stage-instructor.tsx - The instructor controls component with StageRow that shows completion counts
• apps/api/src/routes/admin/group-activities.ts - Endpoint that returns groups with members (name, email, joined status)
• apps/api/src/routes/admin/activity-stages.ts - Status endpoint that returns stage info including isGrouped
• apps/api/src/routes/admin/roster.ts - Photo serving endpoint /api/admin/roster/photo/:uin

The current status endpoint returns isGrouped boolean per stage and completion counts, but does NOT return the actual group membership data (who is in which group with photos). A new API endpoint or enhancement would be needed to provide group membership with photo information to the instructor view.

Summary:

1. Primary Request and Intent:

   • Completed: Implement a flashcard system at /roster/flashcards for learning student names using Leitner box spaced repetition, with photo display, keyboard shortcuts, progress tracking, and completion stats.
   • Completed: Fix multiple animation/transition issues with the flashcard card (flip animation name leaks, photo size changes, hard transitions, hydration errors).
   • Completed: Fix all lint errors (react-hooks/purity, react-hooks/refs, stale eslint-disable comments).
   • Completed: Rename /instructors route to /educators with terminology updates.
   • Completed: Version bump to 2026.2.16.
   • In Progress (Plan Mode): Add group awareness to the instructor activity page — for each group segment, show student photos indicating who is working with whom, with names on hover.

2. Key Technical Concepts:

   • Leitner box spaced repetition system (4 boxes, weighted random selection)
   • React hydration: Math.random() in useState init causes server/client mismatch — use deterministic values
   • React strict mode lint rules: react-hooks/purity (no Date.now() during render), react-hooks/refs (no ref.current during render)
   • useMemo vs useRef for render-safe derived data
   • CSS 3D flip animation (backface-visibility, transform-style: preserve-3d) — ultimately removed due to name visibility during rotation
   • Fade-out/swap/fade-in pattern for card transitions (200ms opacity transition, swap data while invisible)
   • Next.js 16 removed @next/next/no-img-element rule — eslint-disable comments for it cause errors
   • Activity stages system: sessions, stage timings, completions, group activities with join codes
   • Roster photo system: CSV-based UIN mapping, JPEG photos served from data/:semester/photos/:uin.jpg
   • Admin group activities API returns groups with members (name, email, joined status)

3. Files and Code Sections:

   • apps/web/app/roster/flashcards/leitner.ts (Created)

     • Pure TypeScript Leitner box algorithm with typed Boxes interface
     • Exports: initializeState, selectNextCard, markCorrect, markIncorrect, isSessionComplete, getBoxCounts
     • Uses as const assertions for box iteration to satisfy strict TypeScript

   • apps/web/app/roster/flashcards/page.tsx (Created)

     • Server component with auth check, fetches roster via serverApiFetch, filters to students with photos
     • Passes FlashcardStudent[] to FlashcardsClient

   • apps/web/app/roster/flashcards/client.tsx (Created, heavily iterated)

     • Final version: No flip animation, simple card with photo + name that fades in
     • Uses useMemo for studentMap and preloadEmails (not useRef — lint requirement)
     • endTime captured in state via setEndTime(Date.now()) in callback (not during render)
     • Fade-out/fade-in transition between students: cardVisible state controls opacity, 200ms FADE_MS, swap during invisible
     • Deterministic first card: students[0]!.email (not selectNextCard with Math.random())
     • Keyboard shortcuts: Space/Enter to reveal, ArrowRight/Enter for correct, ArrowLeft/Backspace for incorrect

   • apps/web/app/roster/page.tsx (Modified)

     • Added Link and Button imports
     • Added hasPhotos check and "Practice Names" button with data-testid="practice-names-button"
     • Removed stale eslint-disable-next-line @next/next/no-img-element comment

   • testing/e2e/tests/flashcards.spec.ts (Created)

     • Tests: unauthenticated redirect, student empty state, instructor access (uses .or() for game/empty), roster page integration

   • testing/e2e/playwright.config.ts (Modified)

     • Added flashcards project entry

   • apps/web/styles/globals.css (Modified then reverted)

     • Flip CSS was added then removed multiple times; final state has NO flashcard CSS additions

   • apps/web/app/educators/page.tsx (Renamed from instructors/)

     • Updated import to @content/educators.mdx, metadata title to "For Educators", testid to educators-page, function name to EducatorsPage

   • content/educators.mdx (Renamed from instructors.mdx)

     • Heading changed from "# For Instructors" to "# For Educators"

   • testing/e2e/tests/instructor-chat.spec.ts (Modified)

     • All /instructors URLs changed to /educators, testid instructors-page → educators-page

   • For current plan mode task, key files read:

     • apps/web/components/mdx/activity-stage-instructor.tsx — The instructor controls UI. StageRow component shows completion counts per stage. For grouped stages shows "X of Y groups". Currently has NO group membership visualization. This is where photo clusters need to be added.
     • apps/api/src/routes/admin/activity-stages.ts — Status endpoint returns isGrouped boolean per stage and completion/total counts but NOT actual group member details.
     • apps/api/src/routes/admin/group-activities.ts — Returns full group membership with {id, name, email, joinCode, joined, joinedAt} per member. Endpoint: GET /api/admin/group-activities/:groupKey/:activityId?semester=...
     • apps/api/src/routes/admin/roster.ts — Serves photos at GET /api/admin/roster/photo/:uin. Roster list returns {name, email, uin, hasPhoto}.

4. Errors and fixes:

   • TypeScript errors with Record<number, string[]>: Indexing returned undefined. Fixed by creating explicit Boxes interface with keys 1-4.
   • E2E test failure: Instructor expected empty state but real roster has students with photos. Fixed with .or() matcher.
   • Name visible during card flip: User reported seeing name while card rotates. Multiple attempts to fix with delayed swaps, fade-out/fade-in, moving name off card. User ultimately said "drop the flip" — final solution: no flip, simple opacity fade-in for name.
   • Hydration mismatch: selectNextCard uses Math.random() in useState init. Fixed with deterministic students[0]!.email.
   • react-hooks/purity: Date.now() called during render. Fixed by storing endTime in state, only set in callback.
   • react-hooks/refs: useRef.current accessed during render for studentMap and preloadEmails. Fixed by converting to useMemo.
   • @next/next/no-img-element: Rule no longer exists in Next.js 16, eslint-disable comments for it cause errors. Fixed by removing the comments.

5. Problem Solving:

   • The flip animation was the most challenging iterative problem. The core issue: when swapping student data, any visible content changes abruptly mid-animation. Multiple approaches were tried (delayed swap, fade wrapper, name off card, name opacity control). The user ultimately preferred no flip — just a card with photo and name that fades in.
   • React strict mode linting caught multiple impurity issues that needed architectural changes (refs → useMemo, render-time Date.now → state capture).

6. All user messages:

   • "Implement the following plan: [detailed flashcard system plan]"
   • "OK cool! A few notes. There's a brief moment when the card is turning where I can see the name of the next student, which isn't good. Can we make the faces not change size when the name is revealed? Other than that it's awesome! I love the keyboard integration."
   • "Now there's a hard transition between faces after the card rotates back. Can you use the face on the front but just not show the name until after the animation finishes and it's hidden?"
   • "Nope, still broken. Now the name fades out but is visible for a second. Step back and redesign this. It should not be that hard. The flip animation was nice."
   • "the name is STILL VISIBLE as the card rotates! Why is this so hard? Just make the name not visible! I'm confused why you're struggling with this."
   • "The name should start out as not visible and only become visible later."
   • "Sigh. Now what's the point of the flip? Here's what I wanted. Flip the card and, as it flips, fade in the name, which should be on the card. If the name is not on the card then there's no reason to flip! Then it's just annoying."
   • "OK, let's just drop the flip. It's annoying. Just fade in the name on the card."
   • "/commitall" (first commit)
   • "/commitall" (empty — already committed)
   • "Please run bun check and fix the error."
   • "/commitall" (lint fixes commit)
   • "Let's rename the /instructors route to /educators and also use that term on that page: 'For Educators' and etc."
   • "/commitall" (educators rename commit)
   • "/commitall" (version bump commit)
   • "OK! Now, I'd like to add more group awareness to the instructor activity page. For each group segment, as groups are formed, please use the photos to indicate who is working with who. Names can be on hover."

7. Pending Tasks:

   • In plan mode: Design and implement group photo visualization on the instructor activity page for grouped stages. Need to:
     • Determine how to get group membership + photo data to the instructor UI (the existing admin group activities API has member info but not UINs for photos; the roster API has UIN→photo mapping)
     • Add group photo clusters to the StageRow component in activity-stage-instructor.tsx for grouped stages
     • Show student photos grouped together, with names on hover

8. Current Work: I am in plan mode, Phase 1-2 (exploration/design). I have read the key files for the instructor activity system:

   • apps/web/components/mdx/activity-stage-instructor.tsx (the instructor controls UI)
   • apps/api/src/routes/admin/activity-stages.ts (status endpoint)
   • apps/api/src/routes/admin/group-activities.ts (group membership endpoint)
   • apps/api/src/routes/admin/roster.ts (photo serving)

   I need to understand the data gap: the status endpoint knows which stages are grouped but doesn't return group membership details. The group activities endpoint has members but needs groupKey and activityId which aren't available in the stage status flow. A new API endpoint or enhancement is needed to bridge this gap. I also need to map user emails to UINs for photo URLs.

9. Optional Next Step: Continue plan mode — write the implementation plan to the plan file and call ExitPlanMode. The user's most recent request: "I'd like to add more group awareness to the instructor activity page. For each group segment, as groups are formed, please use the photos to indicate who is working with who. Names can be on hover." I need to design the API changes and frontend component changes, then present the plan for approval.

If you need specific details from before compaction (like exact code snippets, error messages, or content you generated), read the full transcript at: ~/.claude/projects/-Users-challen-www-usingandunderstanding-ai/da526847-cef4-4927-90df-fba4cbf7473c.jsonl Please continue the conversation from where we left off without asking the user any further questions. Continue with the last task that you were asked to work on.

I'd like to write tests for this. Is that possible?