# Email Verification Code Implementation

## Overview

This implementation adds a secure email verification system that requires users to verify their email address with a 6-digit code before completing registration. This ensures only real email addresses (Gmail, Yahoo, etc.) can be used.

## Features

✅ **3-Step Registration Process:**
1. **Email Input** - User enters their email address
2. **Code Verification** - User enters the 6-digit code sent to their email
3. **Account Creation** - User completes registration with username and password

✅ **Security Features:**
- 6-digit verification code sent via email
- Code expires in 10 minutes
- Verification token valid for 15 minutes
- Email must be verified before account creation
- Prevents duplicate email registrations
- Works with all email providers (Gmail, Yahoo, Outlook, etc.)

## Files Created/Modified

### New API Routes:
1. **`app/api/auth/send-verification-code/route.ts`**
   - Sends 6-digit verification code to user's email
   - Checks if email already exists
   - Stores code temporarily (10-minute expiration)
   - Uses Resend email service

2. **`app/api/auth/verify-code/route.ts`**
   - Verifies the 6-digit code entered by user
   - Generates verification token upon successful verification
   - Returns token for use in registration

3. **`app/api/auth/verify-token/route.ts`**
   - Validates verification token during registration
   - Ensures email was verified before account creation

### Updated Files:
1. **`contexts/supabase-auth-context.tsx`**
   - Added `sendVerificationCode()` function
   - Added `verifyCode()` function
   - Updated `register()` to require verification token

2. **`app/register/page.tsx`**
   - Implemented 3-step registration flow
   - Step 1: Email input and code sending
   - Step 2: Code verification
   - Step 3: Account creation form

## User Flow

### Step 1: Email Verification
1. User enters email address
2. Clicks "Send Verification Code"
3. System sends 6-digit code to email
4. User sees success message

### Step 2: Code Entry
1. User receives email with 6-digit code
2. User enters code in the form
3. Clicks "Verify"
4. System validates code
5. If valid, proceeds to registration form

### Step 3: Account Creation
1. User enters username and password
2. Confirms password
3. Accepts terms and conditions
4. Clicks "Create Account"
5. System verifies token and creates account
6. User redirected to login page

## Email Template

The verification email includes:
- Professional HTML design with BUILDMATE branding
- Large, easy-to-read 6-digit code
- Security notice
- Expiration time (10 minutes)
- Clear instructions

## Configuration

### Required Environment Variables:

```env
# Resend Email Service
RESEND_API_KEY=re_your_api_key_here
RESEND_FROM_EMAIL=BUILDMATE <noreply@yourdomain.com>
```

### Setup Instructions:

1. **Get Resend API Key:**
   - Sign up at [resend.com](https://resend.com)
   - Create API key in dashboard
   - Add to `.env.local`

2. **Configure From Email:**
   - Use verified domain email
   - For testing: `onboarding@resend.dev`

3. **Enable Email Confirmation in Supabase:**
   - Go to Supabase Dashboard
   - Authentication → Settings
   - Enable "Email confirmations"

## Development Mode

In development mode, if `RESEND_API_KEY` is not set:
- Verification code is logged to console
- Code is returned in API response (for testing only)
- Allows testing without email service

**⚠️ Warning:** Remove code from response in production!

## Security Considerations

1. **Code Storage:**
   - Currently stored in memory (Map)
   - For production, use Redis or database
   - Codes expire after 10 minutes

2. **Token Security:**
   - Verification tokens are cryptographically random
   - Tokens expire after 15 minutes
   - One-time use (deleted after registration)

3. **Email Validation:**
   - Checks for duplicate emails before sending code
   - Validates email format
   - Only verified emails can complete registration

## Testing

### Test the Flow:

1. **Go to `/register`**
2. **Enter email** (use real email like Gmail/Yahoo)
3. **Click "Send Verification Code"**
4. **Check email inbox** for 6-digit code
5. **Enter code** in verification form
6. **Complete registration** with username and password
7. **Verify account created** and can login

### Development Testing:

If Resend is not configured:
- Code appears in browser console
- Code also in API response (dev only)
- Can test without actual email

## Error Handling

The system handles:
- Invalid email format
- Duplicate email addresses
- Expired verification codes
- Invalid verification codes
- Missing verification tokens
- Email service failures

## Future Improvements

1. **Persistent Storage:**
   - Move verification codes to Redis or database
   - Better for multi-server deployments

2. **Rate Limiting:**
   - Limit code requests per email/IP
   - Prevent abuse

3. **Code Resend:**
   - Add cooldown period between resends
   - Track resend attempts

4. **Email Templates:**
   - Customize email design
   - Add branding customization

## Troubleshooting

### Code Not Received:
- Check spam folder
- Verify Resend API key is set
- Check Resend dashboard for delivery status
- In development, check console for code

### Code Expired:
- Request new code
- Codes expire after 10 minutes
- Can resend unlimited times

### Registration Fails:
- Ensure code was verified first
- Check verification token is valid
- Verify email not already registered

## Support

For issues:
- Check Resend dashboard for email delivery
- Review server logs for errors
- Verify environment variables are set
- Test with development mode first

---

**Implementation Date:** $(date)
**Status:** ✅ Complete and Ready for Testing