Sprint 139 — Calendar-Based Problem Registration + Week Auto-Calculation

Context

User feedback: "Instead of the two-step select dropdown where weekNumber is manually selected when adding a problem, change it so the user only selects the deadline from a calendar and the week number is automatically calculated internally by the program."

Previous flow:

• User selects "Week 3 of May" from the weekNumber dropdown → selects deadline from a day-of-week select within that week
• DB stores week_number varchar(20) column + deadline timestamp separately
• UX friction requiring the user to enter the same domain concept (study week) twice

Decision (Option A Adopted)

Client derives weekNumber from deadline and includes it in the API payload.

Reasons for choosing Option A:

• No DB schema changes — existing backend logic such as findByWeekAndStudy maintained as-is
• Minimum regression risk (single frontend domain)
• Options B/C have cleaner SSoT structure but separated into individual sprints

Impact Scope (3 Entry Points)

The user feedback's "problem add UI" was actually 2 locations — only (1) was identified during scouting, (2) was discovered during work:

1. /problems/create fullscreen page (admin only)
2. AddProblemModal modal on the /problems list page (more common UI)
3. /problems/[id]/edit edit page (symmetry maintenance)

All three entry points used the same pattern (2-step select) so changed together.

Changes

Wave A — Inspection only (no commit)

• Existing getCurrentWeekLabel(date: Date = new Date()) signature already accepts arbitrary Date argument → no need to add new function, reused as-is
• getWeekOptions/getWeekDates/matchDeadlineToWeekDate were only used in create/edit pages → confirmed removable after Wave B/C

Wave B+C+D — Integrated commit (4dbae8f)

Atomic change required due to shared schemas/utils.

• frontend/src/lib/schemas/problem.ts: Remove weekNumber field
• frontend/src/lib/problem-form-utils.ts: Remove weekNumber from ProblemFormState/ProblemFormErrors/validateProblemForm
• frontend/src/app/[locale]/problems/create/page.tsx: 2-step select → single <Calendar mode="single"> widget, read-only display of derived weekNumber
• frontend/src/app/[locale]/problems/[id]/edit/page.tsx: Same pattern
• New i18n key: problems.form.calculatedWeek ("Auto-calculated: {week}")
• Tests: Added Calendar/buttonVariants mocks, updated weekNumber cases in schemas/utils tests

d1f4e49 — AddProblemModal same change

• ConfirmStep: Remove two-step selects, integrate calendar widget
• Removed unused helpers: generateWeekData/getWeekDateData/WeekOption/DateOption/DAY_KEYS (-178 lines)
• Cleaned up unused i18n keys: weekLabel/weekPlaceholder/deadlinePlaceholder/weekFormat/dateFormat
• Tests: Updated selectWeekAndSubmit helper to calendar click pattern

9301354 — Sprint 139 cleanup

• problem-form-utils.ts: Remove getWeekOptions/getWeekDates/matchDeadlineToWeekDate/DAY_NAMES (-76 lines)
• problem-form-utils.test.ts: Remove describe blocks for above functions (-128 lines)
• Clean up stale jest.mock items in create/edit page tests
• Remove unused i18n keys: form.weekLabel, errors.validation.problem.weekNumberRequired, addModal.dayNames, addModal.validation.weekRequired

a26f9d5 — Critic P1 fix

Codex review caught 2 P1 regressions:

Calling date.toISOString() directly in Calendar onSelect of create/edit pages serializes as local midnight in UTC+ timezones like KST → deadline effectively ends one day early at 00:00 on the intended date. The existing select method normalized to 23:59:59, and AddProblemModal also applied the same normalization, but it was missed in the new create/edit code.

Fix: Apply the same pattern already used in AddProblemModal:

const iso = date
  ? new Date(date.getFullYear(), date.getMonth(), date.getDate(), 23, 59, 59).toISOString()
  : '';

Critic re-verification passed: "P1 regression resolved, no additional defects found."

Verification

• pnpm type-check pass (frontend)
• pnpm lint clean (warnings only, unrelated to existing code)
• pnpm test 1348 tests passed (130 suites, 0 regressions; 1361 → removed 13 unused util tests → 1348)
• CI: 30 SUCCESS / 8 SKIPPED / 0 FAILURE (mergeStateStatus CLEAN)
• Critic 2 rounds (P1 2 → 0)

Branch Discipline ✅

• New branch feat/sprint-139-calendar-based-problem-create (608e276 base)
• 4 atomic commits → PR #181 → Squash merge
• 0 direct commits to main (Sprint 135/136/137/138/139 — 5 consecutive sprints compliant since Sprint 134 violation)

Findings / Separate Seeds

Oracle Dispatch Infrastructure Issue (P1)

• Attempted to spawn Architect via oracle-spawn.sh architect → immediate env: claude: No such file or directory failure in tmux pane
• Root cause estimate: claude CLI not found in PATH of tmux pane environment (separate from Sprint 125 D2 H1 sensitive path protection)
• Workaround: Oracle proceeded directly (PM consensus plan + Wave-unit atomic commits + Critic external verification as supplement — Critic ultimately caught 2 P1 issues, justifying the workaround)
• Sprint 140 seed: oracle-spawn.sh PATH environment check + fallback or explicit error output when claude is not found

Ambiguity in User Feedback's "Add Problem" Scope

• Work began without precisely identifying which UI "add problem" referred to → AddProblemModal discovered additionally during work → included in the same commit bundle
• Lesson: User feedback keywords like "add problem" should be verified with pre-grep for repeated patterns before finalizing the plan

Accumulated Unused i18n Keys

• addModal.dayNames (7 keys × 2 langs), addModal.validation.weekRequired, form.weekLabel, etc. — became unused after changes, but if not cleaned up immediately can cause ko/en mismatches/confusion
• All cleaned up in this sprint. Future i18n key additions/removals are recommended to be included in PR unit cleanup commits.

Critic Invocation Policy Application Example

• Sprint 131~138 had appropriate Critic non-invocation policy for infra yaml/seed changes
• Sprint 139 involved form validation logic + user input flow + timezone normalization with high correctness risk → Critic invoked → 2 P1 issues caught → value of invocation policy proven
• Future policy guide: Critic invocation mandatory when "user input flow changes" or "time processing changes"

Follow-up (PR #183, f9d8420 → main e2879c7)

3 calendar regressions found by user visual verification immediately after PR #181 merge:

1. ko locale not applied — English month names ("April 2026") + English weekday names ("Su Mo Tu We Th Fr Sa") displayed
2. Weekday header grid broken — only Su appears above the first column, remaining MoTuWeThFrSa bunched together above the 4th column
3. Modal left-aligned — calendar not centered

Root Cause

react-day-picker v9.14.0 is installed but frontend/src/components/ui/calendar.tsx uses v8 className keys, which don't match v9 standard keys, causing all 8 classNames to be invalid and falling back to default flex layout.

v8 → v9 className Mapping

Fix

• Updated v9 className key mappings
• Default locale prop set to ko (imported from react-day-picker/locale — date-fns/locale re-export)
• Force weekdays/week to grid grid-cols-7 → uniform 7-column split
• Calendar outer mx-auto w-fit → centered in modal
• AlgoSu design tokens (text-text-3, bg-primary-soft, etc.) applied
• selected/today/range_* states applied via v9 data attribute selectors (data-[selected-single]/data-[range-*])

Verification

• typecheck pass / lint warnings only / 1348 tests pass (0 regressions)
• CI 30 SUCCESS / 8 SKIPPED / 0 FAILURE
• Critic not invoked (UI className update, low code correctness risk)

Lessons

Dependency wrapper component compatibility check was missing from PR pre-flight checklist for major version changes. This case involved react-day-picker being upgraded from v8 → v9 at some point, but the wrapper (calendar.tsx) was not updated, and the regression surfaced when first actually used in Sprint 139. Sprint 140 seed: Add "check wrapper compatibility when major dependency upgrade" item to PR pre-flight checklist.

Sprint 140 Carryover

• Oracle oracle-spawn.sh PATH environment check (Sprint 139, P1)
• Dependency major upgrade wrapper compatibility check (Sprint 139 follow-up — add to PR pre-flight checklist)
• en locale dynamic mapping (next-intl locale ↔ react-day-picker locale connection — out of Sprint 139 follow-up scope)
• Maintain 4 accumulated seeds:
  • github-worker errorFilter wrapper + WeakSet synchronization (Sprint 135 carryover)
  • ai-analysis Python CB schema unification (state 0/0.5/1 → 0/1/2 + name label)
  • CLAUDE.md "ai-feedback" → "ai-analysis" naming correction
  • E2E auto PR CI integration (accumulated since Sprint 134)
• backend weekNumber calculation from deadline (Option B) — separate seed
• week_number column removal (Option C) — separate seed
• Operational verification: demo login broken image recovery after ArgoCD sync (Sprint 138 carryover maintained)