---
phase: 01-foundation-auth
plan: 04
subsystem: auth
tags: [google, oauth, supabase, social-login, react]

# Dependency graph
requires:
  - phase: 01-01
    provides: Supabase client utilities
  - phase: 01-02
    provides: Database schema with profiles table
provides:
  - GoogleSignInButton component with signInWithOAuth
  - Login page with Google OAuth + email form
  - Register page with Google OAuth + email form
  - Google OAuth setup documentation
affects: [01-05-middleware, 01-06-protected-routes]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "Google OAuth via Supabase signInWithOAuth"
    - "Social login button above email form with 'oppure' divider"
    - "Client-side OAuth redirect handling"

key-files:
  created:
    - src/components/auth/google-button.tsx
    - src/components/auth/login-form.tsx
    - src/components/auth/register-form.tsx
    - src/app/(auth)/layout.tsx
    - src/app/(auth)/login/page.tsx
    - src/app/(auth)/register/page.tsx
    - src/components/ui/input.tsx
    - docs/GOOGLE_OAUTH_SETUP.md
  modified:
    - src/lib/utils.ts
    - src/components/ui/button.tsx
    - src/components/ui/card.tsx

key-decisions:
  - "Google button placed above email form (faster option first)"
  - "Created full login/register pages since 01-03 not yet executed (parallel wave)"
  - "Client-side forms instead of Server Actions (simpler for OAuth flow)"

patterns-established:
  - "Social login pattern: GoogleSignInButton component with signInWithOAuth"
  - "Auth page pattern: Card with Google button + 'oppure' divider + email form"
  - "Italian text: 'Accedi con Google', 'oppure', 'Registrati'"

# Metrics
duration: 4min
completed: 2026-01-31
---

# Phase 01 Plan 04: Google OAuth Summary

**Google OAuth login button with signInWithOAuth, integrated into login and register pages with Italian text and setup documentation**

## Performance

- **Duration:** 4 min
- **Started:** 2026-01-31T04:04:21Z
- **Completed:** 2026-01-31T04:08:41Z
- **Tasks:** 3
- **Files created:** 11

## Accomplishments

- Created GoogleSignInButton component with Google icon SVG and signInWithOAuth
- Built complete login and register pages with Google button prominently above email form
- Added "oppure" divider to separate social login from email form
- Created comprehensive Google OAuth setup documentation
- All UI text in Italian per project requirement

## Task Commits

Each task was committed atomically:

1. **Task 1: Create Google Sign-In button component** - `1d454d2` (feat)
2. **Task 2: Add Google button to login and register pages** - `dcbd7e8` (feat)
3. **Task 3: Document Google OAuth setup process** - `bd0df40` (docs)

## Files Created

- `src/lib/utils.ts` - cn() utility for class name merging
- `src/components/ui/button.tsx` - Button component with variants
- `src/components/ui/card.tsx` - Card component with Header, Title, Content
- `src/components/ui/input.tsx` - Input component with error state
- `src/components/auth/google-button.tsx` - Google OAuth button
- `src/components/auth/login-form.tsx` - Email/password login form
- `src/components/auth/register-form.tsx` - Registration form with validation
- `src/app/(auth)/layout.tsx` - Centered auth layout
- `src/app/(auth)/login/page.tsx` - Login page with Google + email
- `src/app/(auth)/register/page.tsx` - Register page with Google + email
- `docs/GOOGLE_OAUTH_SETUP.md` - Setup guide for Google Cloud + Supabase

## Decisions Made

1. **Google button above email form** - Faster login option should be more prominent
2. **Created full auth pages** - Plan runs parallel with 01-03 which also creates these pages; created complete pages with Google integration since 01-03 not yet executed
3. **Client-side forms** - Used client-side state management for forms since OAuth requires client-side redirect handling; Server Actions can be added later if needed

## Deviations from Plan

### Auto-fixed Issues

**1. [Rule 3 - Blocking] Created UI components and forms not in plan scope**
- **Found during:** Task 2 (Add Google button to pages)
- **Issue:** Login/register pages didn't exist (01-03 not yet executed), and plan specifies "If they don't exist, create them with the Google button included"
- **Fix:** Created full auth pages including layout, forms, and UI components
- **Files created:** src/components/ui/input.tsx, src/components/auth/login-form.tsx, src/components/auth/register-form.tsx, src/app/(auth)/layout.tsx
- **Verification:** Build passes, pages render correctly
- **Committed in:** dcbd7e8

---

**Total deviations:** 1 auto-fixed (blocking - parallel plan dependency)
**Impact on plan:** Extended scope to create complete auth UI since parallel plan 01-03 not yet executed. When 01-03 runs, it may need to skip or modify already-created files.

## Issues Encountered

None - plan executed smoothly.

## User Setup Required

**External services require manual configuration.** See `docs/GOOGLE_OAUTH_SETUP.md` for:
- Google Cloud Console OAuth client ID creation
- Supabase Dashboard Google provider configuration
- Testing steps and troubleshooting guide

## Next Phase Readiness

- Google OAuth button ready and functional
- Login and register pages complete
- Auth callback at /auth/callback expected to exist (from 01-01)
- Middleware for session refresh needed (01-05)
- Protected routes needed for /dashboard redirect (01-06)

---
*Phase: 01-foundation-auth*
*Completed: 2026-01-31*