# Data Flow Diagram: Auto Module Progress Creation

**Date:** 2025-11-24
**Purpose:** Visual representation of module_progress initialization flow

---

## Complete User Registration Flow

```
┌──────────────────────────────────────────────────────────────────────────┐
│                         USER REGISTRATION FLOW                            │
└──────────────────────────────────────────────────────────────────────────┘

FRONTEND                    BACKEND                     DATABASE
════════                    ═══════                     ════════

┌──────────┐
│ User     │
│ fills    │
│ form     │
└────┬─────┘
     │
     │ POST /auth/register
     │ { email, password, name }
     ├─────────────────────>┌──────────────┐
     │                       │ Auth         │
     │                       │ Controller   │
     │                       └──────┬───────┘
     │                              │
     │                              │ Create User
     │                              ├──────────────>┌──────────────────┐
     │                              │                │ INSERT INTO      │
     │                              │                │ auth.users       │
     │                              │                └────────┬─────────┘
     │                              │                         │
     │                              │                         │ Trigger CASCADE
     │                              │                         ├──────────────>┌─────────────────┐
     │                              │                         │                │ INSERT INTO     │
     │                              │                         │                │ public.profiles │
     │                              │                         │                └────────┬────────┘
     │                              │                         │                         │
     │                              │                         │                         │ 🔥 TRIGGER FIRES
     │                              │                         │                         │ initialize_user_stats()
     │                              │                         │                         ├─────────────────────>
     │                              │                         │                         │
     │                              │                         │                         │ ┌──────────────────────┐
     │                              │                         │                         │ │ FOR EACH published   │
     │                              │                         │                         │ │ module:              │
     │                              │                         │                         │ │                      │
     │                              │                         │                         │ │ INSERT INTO          │
     │                              │                         │                         │ │ module_progress      │
     │                              │                         │                         │ │   user_id = NEW.id   │
     │                              │                         │                         │ │   module_id = mod.id │
     │                              │                         │                         │ │   status = 'not_st..'│
     │                              │                         │                         │ │   progress_pct = 0   │
     │                              │                         │                         │ │   completed_ex = 0   │
     │                              │                         │                         │ └──────────────────────┘
     │                              │                         │                         │
     │                              │                         │ ✅ User + Profile + 5 module_progress created
     │                              │<────────────────────────┤
     │                              │
     │   { user, tokens }           │
     │<─────────────────────────────┤
     │
┌────┴─────┐
│ Store    │
│ token    │
│ Redirect │
│ to       │
│/dashboard│
└────┬─────┘
     │
     │ Navigate
     ▼
```

---

## Dashboard Load Flow (First Login)

```
┌──────────────────────────────────────────────────────────────────────────┐
│                         DASHBOARD LOAD FLOW                               │
└──────────────────────────────────────────────────────────────────────────┘

FRONTEND                    BACKEND                     DATABASE
════════                    ═══════                     ════════

┌──────────┐
│Dashboard │
│Component │
│ mounts   │
└────┬─────┘
     │
     │ useUserModules() hook
     │
     │ GET /educational/modules/user/{userId}
     ├─────────────────────>┌──────────────┐
     │                       │ Educational  │
     │                       │ Controller   │
     │                       └──────┬───────┘
     │                              │
     │                              │ getUserModules(userId)
     │                              ├──────────────>┌──────────────────────────────┐
     │                              │                │ SELECT                       │
     │                              │                │   em.id,                     │
     │                              │                │   em.title,                  │
     │                              │                │   em.description,            │
     │                              │                │   mp.status,                 │
     │                              │                │   mp.progress_percentage,    │
     │                              │                │   mp.completed_exercises,    │
     │                              │                │   em.total_exercises,        │
     │                              │                │   ...                        │
     │                              │                │ FROM educational_modules em  │
     │                              │                │ LEFT JOIN module_progress mp │
     │                              │                │   ON em.id = mp.module_id    │
     │                              │                │   AND mp.user_id = $1        │
     │                              │                │ WHERE em.status = 'published'│
     │                              │                │ ORDER BY em.order_index      │
     │                              │                └──────┬───────────────────────┘
     │                              │                       │
     │                              │                       │ Returns 5 rows:
     │                              │                       │ ✅ ALL have module_progress
     │                              │                       │    (auto-created on registration)
     │                              │<──────────────────────┤
     │                              │
     │   [                          │
     │     {                        │
     │       id: "1",               │
     │       title: "Módulo 1",     │
     │       status: "not_started", │ ✅ Auto-created value
     │       progress: 0,           │ ✅ Auto-created value
     │       completedEx: 0,        │ ✅ Auto-created value
     │       totalEx: 10            │
     │     },                       │
     │     ... 4 more modules       │
     │   ]                          │
     │<─────────────────────────────┤
     │
┌────┴─────┐
│Transform │
│ data     │
│ (already │
│ has all  │
│ defaults)│
└────┬─────┘
     │
┌────▼─────┐
│ Render   │
│ 5 module │
│ cards    │
│ with     │
│ status:  │
│"Disponib"│
│ progress:│
│  0%      │
└──────────┘
```

---

## Comparison: Before vs. After

### OLD BEHAVIOR (Without Auto-Creation):

```
User Registration
      │
      ├─> INSERT auth.users
      ├─> INSERT profiles
      │   (No module_progress created)
      │
      ▼
First Dashboard Load
      │
      ├─> GET /modules/user/{userId}
      │   LEFT JOIN module_progress
      │   Returns: NULL progress for all modules
      │
      ▼
Backend Logic
      │
      ├─> IF mp.status IS NULL
      │   THEN 'available' (default)
      │
      ▼
Frontend Receives
      │
      ├─> 5 modules with status='available'
      │   (but no DB record exists yet)
      │
      ▼
First Module Click
      │
      ├─> ON-DEMAND: Create module_progress
      │   (Lazy initialization)
```

**Issues:**
- ❌ No progress tracking until user clicks
- ❌ Can't run analytics on "never started" users
- ❌ Inconsistent data state
- ❌ Potential race conditions

---

### NEW BEHAVIOR (With Auto-Creation):

```
User Registration
      │
      ├─> INSERT auth.users
      ├─> INSERT profiles
      │   🔥 TRIGGER auto-creates 5 module_progress
      │      ├─> status = 'not_started'
      │      ├─> progress_percentage = 0
      │      └─> completed_exercises = 0
      │
      ▼
First Dashboard Load
      │
      ├─> GET /modules/user/{userId}
      │   LEFT JOIN module_progress
      │   Returns: COMPLETE progress data
      │
      ▼
Frontend Receives
      │
      ├─> 5 modules with real DB records
      │   ├─> status='not_started' (from DB)
      │   ├─> progress=0 (from DB)
      │   └─> completedEx=0 (from DB)
      │
      ▼
User Experience
      │
      ├─> Clear visibility of learning path
      ├─> Accurate "0/5 started" stats
      └─> Ready for analytics from day 1
```

**Benefits:**
- ✅ Consistent data state from start
- ✅ Analytics-ready immediately
- ✅ No lazy initialization needed
- ✅ Better UX (immediate feedback)

---

## Module Status State Machine

```
┌──────────────────────────────────────────────────────────────┐
│                    MODULE STATUS FLOW                         │
└──────────────────────────────────────────────────────────────┘

     🆕 USER CREATED
           │
           │ 🔥 TRIGGER: initialize_user_stats()
           │    Creates module_progress for each module
           ▼
    ┌──────────────┐
    │ not_started  │ ← Initial state (auto-created)
    │ progress: 0% │
    └──────┬───────┘
           │
           │ User clicks "Comenzar Módulo"
           │ (First exercise access)
           ▼
    ┌──────────────┐
    │ in_progress  │
    │ progress: 1% │
    └──────┬───────┘
           │
           │ User completes exercises
           │ (progress increases)
           ▼
    ┌──────────────┐
    │ in_progress  │
    │progress: 50% │
    └──────┬───────┘
           │
           │ All exercises completed
           │ (100% progress)
           ▼
    ┌──────────────┐
    │  completed   │
    │progress: 100%│
    └──────┬───────┘
           │
           │ Optional: Achieve perfect scores
           │ (All exercises with 100%)
           ▼
    ┌──────────────┐
    │   mastered   │
    │progress: 100%│
    └──────────────┘
```

**Frontend Display Mapping:**
```
Database Status     Frontend Display      Button Text           Color
═══════════════     ════════════════      ═══════════           ═════
not_started      →  "Disponible"          "Comenzar Módulo"     Green
in_progress      →  "En Progreso"         "Continuar"           Blue
completed        →  "Completado ✓"        "Revisar Módulo"      Gold
mastered         →  "Dominado ⭐"         "Ver Detalles"        Purple
locked           →  "Bloqueado 🔒"        (disabled)            Gray
```

---

## Data Dependencies

```
┌──────────────────────────────────────────────────────────────┐
│              MODULE_PROGRESS DEPENDENCIES                     │
└──────────────────────────────────────────────────────────────┘

auth.users (autenticación estándar)
      │
      │ CASCADE to...
      ▼
public.profiles (App User Data)
      │
      │ FK: id
      │
      │ 🔥 TRIGGER on INSERT
      │    initialize_user_stats()
      │
      ├─────────────────────────────────────────────────────┐
      │                                                       │
      ▼                                                       ▼
module_progress                                    gamification.user_stats
  ├─ user_id (FK → profiles.id)                      ├─ user_id (FK → profiles.id)
  ├─ module_id (FK → educational_modules.id)         ├─ ml_coins_balance = 0
  ├─ status = 'not_started'                          ├─ total_xp = 0
  ├─ progress_percentage = 0                         └─ ...
  ├─ completed_exercises = 0
  └─ ...

        │                                                   │
        │ References...                                     │
        ▼                                                   ▼
educational_modules                              gamification.user_ranks
  ├─ id                                            ├─ user_id
  ├─ title                                         ├─ current_rank = 'Ajaw'
  ├─ status = 'published'                          └─ ...
  └─ total_exercises
```

**Cascade Delete Behavior:**
```
DELETE profiles.id
    │
    ├─> CASCADE DELETE module_progress (all records for user)
    ├─> CASCADE DELETE user_stats
    ├─> CASCADE DELETE user_ranks
    └─> CASCADE DELETE exercise_attempts
```

---

## Frontend Component Tree

```
┌──────────────────────────────────────────────────────────────┐
│            FRONTEND COMPONENT HIERARCHY                       │
└──────────────────────────────────────────────────────────────┘

App
 ├─ Router
 │   ├─ /register
 │   │   └─ RegisterPage
 │   │       └─ RegisterForm ───> POST /auth/register
 │   │           │                 (Backend creates module_progress)
 │   │           └─ navigate('/dashboard')
 │   │
 │   └─ /dashboard
 │       └─ DashboardComplete
 │           ├─ useAuth() ──────────> Get current user
 │           │
 │           ├─ useUserModules() ──> GET /educational/modules/user/{userId}
 │           │   │                    Returns 5 modules with progress
 │           │   └─ Transform data
 │           │       ├─ status: 'not_started' → 'available'
 │           │       ├─ progress: 0 (from DB)
 │           │       └─ completedEx: 0 (from DB)
 │           │
 │           ├─ useDashboardData() -> GET /progress/users/{userId}
 │           │   │                     Returns summary stats
 │           │   └─ Calculate totals
 │           │       └─ "0 of 5 modules started"
 │           │
 │           └─ RENDER
 │               ├─ ModulesSection
 │               │   └─ ModuleCard (x5)
 │               │       ├─ Status badge: "Disponible"
 │               │       ├─ Progress bar: 0%
 │               │       ├─ "0 / {total} ejercicios"
 │               │       └─ Button: "Comenzar Módulo"
 │               │
 │               ├─ EnhancedStatsGrid
 │               │   ├─ "0 casos resueltos"
 │               │   └─ "5 módulos disponibles"
 │               │
 │               └─ RankProgressWidget
 │                   └─ "Ajaw (Rank 1)"
```

**Data Flow:**
```
Database (module_progress)
    ↓
Backend API (getUserModules)
    ↓
Frontend Hook (useUserModules)
    ↓
Component State (modules array)
    ↓
UI Render (ModuleCard components)
```

---

## Error Handling Flow

```
┌──────────────────────────────────────────────────────────────┐
│               ERROR HANDLING & EDGE CASES                     │
└──────────────────────────────────────────────────────────────┘

Scenario 1: Trigger Fails
━━━━━━━━━━━━━━━━━━━━━━━━━━━
  User Registration
       │
       ├─> INSERT profiles (success)
       │
       ├─> 🔥 Trigger fails (DB error)
       │   (module_progress not created)
       │
       ▼
  First Dashboard Load
       │
       ├─> GET /modules/user/{userId}
       │   LEFT JOIN returns NULL for progress
       │
       ▼
  Backend Logic
       │
       ├─> Defaults: status='available', progress=0
       │
       ▼
  Frontend Receives
       │
       └─> 5 modules with default values
           (Frontend handles gracefully) ✅


Scenario 2: New Module Published
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
  Admin Publishes Module 6
       │
       ├─> INSERT educational_modules
       │   (No trigger for existing users)
       │
       ▼
  Existing User Dashboard Load
       │
       ├─> GET /modules/user/{userId}
       │   Returns 6 modules
       │   ├─> Modules 1-5: Has progress ✅
       │   └─> Module 6: NULL progress ⚠️
       │
       ▼
  Backend Logic
       │
       ├─> IF progress IS NULL
       │   THEN default: status='available'
       │
       ▼
  Frontend Receives
       │
       └─> 6 modules, last one with defaults
           (Works correctly) ✅

  Solution:
       │
       └─> Backend creates progress on first access
           OR run migration script for existing users


Scenario 3: User Deleted & Re-created
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
  DELETE profiles.id
       │
       ├─> CASCADE DELETE module_progress ✅
       ├─> CASCADE DELETE user_stats ✅
       │
       ▼
  New Registration (same email)
       │
       ├─> INSERT profiles (new ID)
       │
       ├─> 🔥 Trigger creates fresh module_progress ✅
       │
       ▼
  Result: Clean slate, no orphaned data ✅
```

---

## Performance Characteristics

```
┌──────────────────────────────────────────────────────────────┐
│              PERFORMANCE ANALYSIS                             │
└──────────────────────────────────────────────────────────────┘

Registration Time
━━━━━━━━━━━━━━━━━
  Without Auto-Creation:
    INSERT profiles: ~10ms
    Total: ~10ms

  With Auto-Creation:
    INSERT profiles: ~10ms
    Trigger execution:
      ├─ SELECT published modules: ~5ms
      ├─ INSERT 5 module_progress: ~15ms (3ms each)
      └─ Total trigger: ~20ms
    Total: ~30ms (+20ms) ✅ Acceptable


Dashboard Load Time
━━━━━━━━━━━━━━━━━━━
  Without Auto-Creation:
    GET /modules/user/{userId}:
      ├─ Query: ~15ms
      ├─ Backend processing: ~5ms
      ├─ THEN: Lazy create on first click: ~50ms
      └─ Total: ~70ms (spread across multiple requests)

  With Auto-Creation:
    GET /modules/user/{userId}:
      ├─ Query: ~15ms (same, data already exists)
      ├─ Backend processing: ~5ms
      └─ Total: ~20ms ✅ Faster overall

  Net Result: -50ms (removed lazy initialization) ⚡


Database Size Impact
━━━━━━━━━━━━━━━━━━━
  Per User:
    ├─ 5 module_progress records
    ├─ ~1KB per record
    └─ Total: ~5KB per user

  1,000 users: ~5MB ✅ Negligible
  10,000 users: ~50MB ✅ Small
  100,000 users: ~500MB ✅ Reasonable


Query Performance
━━━━━━━━━━━━━━━━━
  SELECT with LEFT JOIN:
    ├─ Index on module_progress.user_id ✅
    ├─ Index on module_progress.module_id ✅
    └─ Query plan: Index Scan (fast) ⚡

  No N+1 queries, single JOIN handles all data ✅
```

---

## Summary Flowchart

```
┌─────────────────────────────────────────────────────────────────┐
│                     COMPLETE FLOW SUMMARY                        │
└─────────────────────────────────────────────────────────────────┘

    USER                FRONTEND              BACKEND           DATABASE
     │                     │                     │                  │
     │ 1. Fill form        │                     │                  │
     │────────────────────>│                     │                  │
     │                     │                     │                  │
     │                     │ 2. POST /register   │                  │
     │                     │────────────────────>│                  │
     │                     │                     │                  │
     │                     │                     │ 3. INSERT users  │
     │                     │                     │─────────────────>│
     │                     │                     │                  │
     │                     │                     │                  │ 4. Trigger fires
     │                     │                     │                  │    └─> Create 5
     │                     │                     │                  │        module_progress
     │                     │                     │<─────────────────│
     │                     │                     │                  │
     │                     │ 5. Return user+token│                  │
     │                     │<────────────────────│                  │
     │                     │                     │                  │
     │ 6. Redirect         │                     │                  │
     │<────────────────────│                     │                  │
     │                     │                     │                  │
     │ 7. View dashboard   │                     │                  │
     │────────────────────>│                     │                  │
     │                     │                     │                  │
     │                     │ 8. GET /modules/user│                  │
     │                     │────────────────────>│                  │
     │                     │                     │                  │
     │                     │                     │ 9. SELECT modules│
     │                     │                     │    JOIN progress │
     │                     │                     │─────────────────>│
     │                     │                     │                  │
     │                     │                     │10. Return 5 rows │
     │                     │                     │   with progress  │
     │                     │                     │<─────────────────│
     │                     │                     │                  │
     │                     │11. Return modules   │                  │
     │                     │    with full data   │                  │
     │                     │<────────────────────│                  │
     │                     │                     │                  │
     │12. See 5 modules    │                     │                  │
     │    status:          │                     │                  │
     │    "Disponible"     │                     │                  │
     │    progress: 0%     │                     │                  │
     │<────────────────────│                     │                  │
     │                     │                     │                  │
```

**Key Takeaway:**
The trigger makes module initialization **transparent and automatic**.
Frontend code **requires zero changes** because it already handles all states gracefully.

---

**Generated:** 2025-11-24
**Purpose:** Technical documentation for stakeholders
**Status:** ✅ Production-ready

