╔══════════════════════════════════════════════════════════════════════════════╗
║                    QR CODE AUTHENTICATION FEATURE                            ║
║                          IMPLEMENTATION COMPLETE                             ║
╚══════════════════════════════════════════════════════════════════════════════╝

📁 FILES CREATED/MODIFIED:
═══════════════════════════════════════════════════════════════════════════════

✅ Database Layer:
   📄 sql/migrations/add_user_qr_auth_table.sql    [NEW]
   📄 models/user_qr_auth.php                      [NEW]

✅ Backend API:
   📄 api/controllers/UsersController.php          [MODIFIED]
      ➜ generateQRAuth($userId)
      ➜ verifyQRAuth()
      ➜ getQRAuth($userId)
      ➜ revokeQRAuth($userId, $authId)

✅ Frontend UI:
   📄 FrontEnd/js/modules/Access/UserAccessManager.js [MODIFIED]
      ➜ Added QR code column to users table
      ➜ Added showGenerateQRModal() function
      ➜ Integrated QRCode.js library

✅ Documentation:
   📄 QR_CODE_AUTH_API.md                         [NEW]
   📄 QR_CODE_AUTH_DIAGRAM.md                     [NEW]
   📄 QR_CODE_AUTH_CHANGES_SUMMARY.md             [NEW]
   📄 test_qr_auth_api.sh                         [NEW]

═══════════════════════════════════════════════════════════════════════════════

🔑 KEY FEATURES:
═══════════════════════════════════════════════════════════════════════════════

✓ UUIDv7 Primary Keys      - Time-sortable, globally unique identifiers
✓ Nullable Expiration      - QR codes can be permanent or time-limited
✓ Configurable Capabilities - Basic access, Read, Write, Admin permissions
✓ Secure Secret Generation - 32-byte cryptographically secure random
✓ Bcrypt Hashing          - Additional security layer
✓ Usage Tracking          - Count and timestamp tracking
✓ Revocation Support      - Deactivate QR codes anytime
✓ User-Friendly UI        - Simple modal interface for generation
✓ Download Functionality  - Save QR codes as PNG images

═══════════════════════════════════════════════════════════════════════════════

🗄️ DATABASE SCHEMA:
═══════════════════════════════════════════════════════════════════════════════

Table: user_qr_auth
┌────────────────┬──────────────┬────────────────────────────────────┐
│ Field          │ Type         │ Description                        │
├────────────────┼──────────────┼────────────────────────────────────┤
│ auth_id        │ VARCHAR(36)  │ UUIDv7 primary key                 │
│ user_id        │ VARCHAR(36)  │ Foreign key to users table         │
│ secret         │ VARCHAR(255) │ 64-character hex secret            │
│ hashed         │ VARCHAR(255) │ Bcrypt hash of secret              │
│ capabilities   │ JSONB        │ Array of permissions               │
│ created_at     │ TIMESTAMP    │ Creation timestamp                 │
│ expires_at     │ TIMESTAMP    │ Expiration (NULL = no expiry) ⭐   │
│ is_active      │ BOOLEAN      │ Active status flag                 │
│ last_used_at   │ TIMESTAMP    │ Last usage timestamp               │
│ use_count      │ INTEGER      │ Number of verifications            │
│ isDeleted      │ BOOLEAN      │ Soft delete flag                   │
└────────────────┴──────────────┴────────────────────────────────────┘

═══════════════════════════════════════════════════════════════════════════════

🔗 API ENDPOINTS:
═══════════════════════════════════════════════════════════════════════════════

1. POST /api/users/{userId}/generateQRAuth
   ➜ Generate new QR authentication credentials
   ➜ Input:  capabilities, expires_in_hours (optional)
   ➜ Output: QR data, secret, hash, auth_id

2. POST /api/users/verifyQRAuth
   ➜ Verify QR code credentials
   ➜ Input:  user_id, secret, hashed
   ➜ Output: User data with capabilities

3. GET /api/users/{userId}/qrAuth
   ➜ List all QR auths for user
   ➜ Output: Array of QR auth records (no secrets)

4. DELETE /api/users/{userId}/qrAuth/{authId}
   ➜ Revoke specific QR authentication
   ➜ Output: Revocation confirmation

═══════════════════════════════════════════════════════════════════════════════

🖥️ USER INTERFACE:
═══════════════════════════════════════════════════════════════════════════════

Location: User Access Manager → Organizations Tab → Users Table

New Column: "QR Code" with 🔲 icon button

Modal Features:
  ☐ Set Expiration (checkbox) ⭐ NEW
    └─ Expiration Hours (1-720) - Only shown when checked
  ☑ Basic Access
  ☐ Read
  ☐ Write
  ☐ Admin
  
Actions:
  [Cancel]  [Generate QR Code]

After Generation:
  • Display 256x256 QR code image
  • Show user ID, expiration, capabilities
  • [Close]  [Download QR Code]

═══════════════════════════════════════════════════════════════════════════════

📊 USAGE EXAMPLES:
═══════════════════════════════════════════════════════════════════════════════

Generate QR with NO expiration (permanent):
  POST /api/users/abc-123/generateQRAuth
  { "capabilities": ["basic_access"] }

Generate QR with 24-hour expiration:
  POST /api/users/abc-123/generateQRAuth
  { "capabilities": ["basic_access"], "expires_in_hours": 24 }

Verify QR code:
  POST /api/users/verifyQRAuth
  { "user_id": "abc-123", "secret": "64-char-hex..." }

═══════════════════════════════════════════════════════════════════════════════

🚀 INSTALLATION:
═══════════════════════════════════════════════════════════════════════════════

Step 1: Run Database Migration
  $ psql -U postgres -d your_database -f sql/migrations/add_user_qr_auth_table.sql

Step 2: Test the API (optional)
  $ chmod +x test_qr_auth_api.sh
  $ ./test_qr_auth_api.sh

Step 3: Access the UI
  Navigate to: Dashboard → User Access Manager → Organizations Tab
  Click QR icon next to any user

═══════════════════════════════════════════════════════════════════════════════

⭐ KEY UPDATES (October 25, 2025):
═══════════════════════════════════════════════════════════════════════════════

1. UUIDv7 Primary Key
   • Changed from SERIAL id to VARCHAR(36) auth_id
   • Better distributed database support
   • Time-sortable identifiers

2. Nullable Expiration
   • expires_at is now NULL by default
   • QR codes can be permanent or time-limited
   • UI checkbox to enable/disable expiration
   • Display shows "Never (No Expiration)" when null

═══════════════════════════════════════════════════════════════════════════════

🔒 SECURITY:
═══════════════════════════════════════════════════════════════════════════════

✓ Cryptographically secure secret generation (random_bytes)
✓ Bcrypt hashing with default cost factor
✓ Optional expiration timestamps
✓ Active/inactive status control
✓ Revocation capability
✓ Usage audit trail (count + timestamp)
✓ Single active QR per user at a time

═══════════════════════════════════════════════════════════════════════════════

📚 DOCUMENTATION:
═══════════════════════════════════════════════════════════════════════════════

Complete API Reference:     QR_CODE_AUTH_API.md
Architecture & Flow:         QR_CODE_AUTH_DIAGRAM.md
Changes Summary:             QR_CODE_AUTH_CHANGES_SUMMARY.md
Test Script:                 test_qr_auth_api.sh

═══════════════════════════════════════════════════════════════════════════════
                              READY FOR PRODUCTION
═══════════════════════════════════════════════════════════════════════════════