# Orion Multi-Tenant URL Routing Guide

## Quick Answer

**How do customers access a store's storefront in Orion?**

There are three ways depending on the deployment mode:

**⚠️ Important:** This guide describes **customer-facing storefront routes**. For store dashboard/management routes, see [Store Frontend Architecture](../../frontend/store/architecture.md). The storefront uses `/platforms/{platform_code}/storefront/{store_code}/*` in dev path-based mode, while the store dashboard uses `/platforms/{platform_code}/store/{store_code}/*`. In production, the domain IS the storefront (root path `/`), and staff access is at `/store/`.

### 1. **SUBDOMAIN MODE** (Production - Recommended)
```
https://STORE_SUBDOMAIN.platform-domain.lu/
https://STORE_SUBDOMAIN.platform-domain.lu/products
https://STORE_SUBDOMAIN.platform-domain.lu/cart
https://STORE_SUBDOMAIN.platform-domain.lu/store/dashboard   (staff)

Example:
https://acme.omsflow.lu/
https://acme.omsflow.lu/products
https://techpro.rewardflow.lu/account/dashboard
https://acme.omsflow.lu/store/dashboard                     (staff)

Per-platform subdomain override:
https://wizatech-rewards.rewardflow.lu/                     (same store as wizatech.omsflow.lu)
```

### 2. **CUSTOM DOMAIN MODE** (Production - Premium)
```
https://STORE_CUSTOM_DOMAIN/
https://STORE_CUSTOM_DOMAIN/products

Example:
https://store.acmecorp.com/
https://shop.techpro.io/cart
```

### 3. **PATH-BASED MODE** (Development Only)
```
http://localhost:PORT/platforms/PLATFORM_CODE/storefront/STORE_CODE/
http://localhost:PORT/platforms/PLATFORM_CODE/storefront/STORE_CODE/products

Example:
http://localhost:8000/platforms/oms/storefront/ACME/products
http://localhost:8000/platforms/loyalty/storefront/TECHPRO/cart
```

---

## Development URL Quick Reference

All development URLs use `http://localhost:8000` as the base.

### Login Pages

| Panel | URL | Description |
|-------|-----|-------------|
| Admin | `/admin/login` | Platform-wide admin panel |
| Merchant | `/merchants/login` | Merchant management panel |
| Store Dashboard | `/platforms/{platform_code}/store/{store_code}/login` | Store staff login |
| Storefront | `/platforms/{platform_code}/storefront/{store_code}/account/login` | Customer login |

### Key Entry Points

| Panel | URL | Description |
|-------|-----|-------------|
| Admin Dashboard | `/admin/` | Admin panel home |
| Merchant Dashboard | `/merchants/dashboard` | Merchant panel home |
| Store Dashboard | `/platforms/{platform_code}/store/{store_code}/dashboard` | Store management |
| Storefront Homepage | `/platforms/{platform_code}/storefront/{store_code}/` | Customer-facing store |
| Platform Homepage | `/platforms/{platform_code}/` | Platform marketing site |

### Full Example (OMS Platform, Store Code "ACME")

```
Admin login:          http://localhost:8000/admin/login
Merchant login:       http://localhost:8000/merchants/login
Store login:          http://localhost:8000/platforms/oms/store/ACME/login
Store dashboard:      http://localhost:8000/platforms/oms/store/ACME/dashboard
Storefront login:     http://localhost:8000/platforms/oms/storefront/ACME/account/login
Storefront homepage:  http://localhost:8000/platforms/oms/storefront/ACME/
Storefront products:  http://localhost:8000/platforms/oms/storefront/ACME/products
Storefront cart:      http://localhost:8000/platforms/oms/storefront/ACME/cart
Storefront checkout:  http://localhost:8000/platforms/oms/storefront/ACME/checkout
Storefront account:   http://localhost:8000/platforms/oms/storefront/ACME/account/dashboard
```

### API Endpoints

```
Admin API:       http://localhost:8000/api/v1/admin/...
Store API:       http://localhost:8000/api/v1/store/...
Storefront API:  http://localhost:8000/api/v1/storefront/...
```

### Notes

- **Admin and Merchant** panels are global — no platform prefix needed.
- **Store and Storefront** panels require the `/platforms/{platform_code}/` prefix in development. This prefix is stripped by `PlatformContextMiddleware` before routing.
- In **production**, storefronts are accessed via subdomain (`acme.omsflow.lu/`) or custom domain. The root path `/` is the storefront.
- The storefront router is **double-mounted** at `/storefront/` and `/storefront/{store_code}/` to support both production and development modes transparently.

---

## Multi-Platform URL Routing

Orion supports multiple platforms (OMS, Loyalty, Site Builder), each with its own marketing site and store ecosystem.

### Platform URL Structure

#### Development Mode (localhost)

| URL | What it serves |
|-----|----------------|
| `/` | Main marketing site homepage (`main` platform) |
| `/about` | Main marketing site about page |
| `/platforms/oms/` | OMS platform homepage |
| `/platforms/oms/pricing` | OMS platform pricing page |
| `/platforms/oms/storefront/{code}/` | Store storefront on OMS |
| `/platforms/oms/admin/` | Admin panel for OMS platform |
| `/platforms/oms/store/{code}/` | Store dashboard on OMS |
| `/platforms/loyalty/` | Loyalty platform homepage |
| `/platforms/loyalty/features` | Loyalty platform features page |

#### Production Mode (custom domains)

| URL | What it serves |
|-----|----------------|
| `orion.lu/` | Main marketing site homepage |
| `orion.lu/about` | Main marketing site about page |
| `omsflow.lu/` | OMS platform homepage |
| `omsflow.lu/pricing` | OMS platform pricing page |
| `omsflow.lu/admin/` | Admin panel for OMS platform |
| `omsflow.lu/store/{code}/` | Store dashboard on OMS |
| `mybakery.omsflow.lu/` | Store storefront (subdomain) |
| `https://mybakery.lu/` | Store storefront (custom domain) |
| `rewardflow.lu/` | Loyalty platform homepage |

**Note:** In production, storefronts are accessed via subdomain (`store.omsflow.lu`) or custom domain (`mybakery.lu`). The root path `/` IS the storefront — the `PlatformContextMiddleware` internally rewrites it to `/storefront/`. Staff dashboards are at `/store/` on the same domain.

### Quick Reference by Platform

#### For "oms" Platform
```
Dev:
  Platform:   http://localhost:8000/platforms/oms/
  Admin:      http://localhost:8000/platforms/oms/admin/
  Store:      http://localhost:8000/platforms/oms/store/{store_code}/
  Storefront: http://localhost:8000/platforms/oms/storefront/{store_code}/

Prod:
  Platform:   https://omsflow.lu/
  Admin:      https://omsflow.lu/admin/
  Store:      https://{store}.omsflow.lu/store/
  Storefront: https://{store}.omsflow.lu/          (subdomain)
  Storefront: https://mybakery.lu/                 (custom domain)
```

#### For "loyalty" Platform
```
Dev:
  Platform:   http://localhost:8000/platforms/loyalty/
  Admin:      http://localhost:8000/platforms/loyalty/admin/
  Store:      http://localhost:8000/platforms/loyalty/store/{store_code}/
  Storefront: http://localhost:8000/platforms/loyalty/storefront/{store_code}/

Prod:
  Platform:   https://rewardflow.lu/
  Admin:      https://rewardflow.lu/admin/
  Store:      https://{store}.rewardflow.lu/store/
  Storefront: https://{store}.rewardflow.lu/       (subdomain)
  Storefront: https://myrewards.lu/                (custom domain)
```

### Platform Routing Logic

```
Request arrives
      │
      ▼
┌─────────────────────────────────────┐
│ Check: Is this production domain?   │
│ (omsflow.lu, rewardflow.lu, etc.)          │
└─────────────────────────────────────┘
      │
      ├── YES → Route to that platform
      │
      ▼ NO (localhost)
┌─────────────────────────────────────┐
│ Check: Does path start with         │
│ /platforms/{code}/ ?                │
└─────────────────────────────────────┘
      │
      ├── YES → Strip prefix, route to platform
      │         /platforms/oms/pricing → /pricing on OMS
      │
      ▼ NO
┌─────────────────────────────────────┐
│ Route to MAIN MARKETING SITE        │
│ (no platform context)               │
│ /faq → Main site FAQ page           │
└─────────────────────────────────────┘
```

### Platform Codes

| Platform | Code | Dev URL | Prod Domain |
|----------|------|---------|-------------|
| Main Marketing | `main` | `localhost:8000/` | `orion.lu` |
| OMS | `oms` | `localhost:8000/platforms/oms/` | `omsflow.lu` |
| Loyalty | `loyalty` | `localhost:8000/platforms/loyalty/` | `rewardflow.lu` |
| Site Builder | `site-builder` | `localhost:8000/platforms/site-builder/` | `sitebuilder.lu` |

**See:** [Multi-Platform CMS Architecture](../multi-platform-cms.md) for content management details.

---

## Three Deployment Modes Explained

### 1. SUBDOMAIN MODE (Production - Recommended)

**URL Pattern:** `https://STORE_SUBDOMAIN.platform-domain/` (root path = storefront)

**Example:**
- Store subdomain: `acme`
- Platform domain: `omsflow.lu`
- Customer Storefront URL: `https://acme.omsflow.lu/`
- Product Catalog: `https://acme.omsflow.lu/products`
- Staff Dashboard: `https://acme.omsflow.lu/store/dashboard`

**How It Works:**
1. Customer visits `https://acme.omsflow.lu/products`
2. `PlatformContextMiddleware` detects subdomain `"acme"`, resolves platform from root domain `omsflow.lu`
3. Middleware rewrites path: `/products` → `/storefront/products` (internal)
4. `store_context_middleware` performs two-step subdomain lookup:
   - First: `SELECT * FROM store_platforms WHERE custom_subdomain = 'acme'` (per-platform override)
   - Fallback: `SELECT * FROM stores WHERE subdomain = 'acme'` (standard subdomain)
5. Sets `request.state.store = Store(ACME Store)`
6. `frontend_type_middleware` detects STOREFRONT from `/storefront` path prefix
7. `theme_context_middleware` loads ACME's theme
8. Routes to storefront handler, renders with ACME's theme and products

**Advantages:**
- Single SSL certificate for all stores (*.orion.lu)
- Easy to manage DNS (just add subdomains)
- Customers don't need to bring their own domain

---

### 2. CUSTOM DOMAIN MODE (Production - Premium)

**URL Pattern:** `https://CUSTOM_DOMAIN/` (root path = storefront)

**Example:**
- Store name: "ACME Store"
- Custom domain: `store.acme-corp.com`
- Customer Storefront URL: `https://store.acme-corp.com/products`

**Database Setup:**
```sql
-- stores table
id | name        | subdomain
1  | ACME Store  | acme

-- store_domains table (links custom domains to stores)
id | store_id | domain              | is_active | is_verified
1  | 1         | store.acme-corp.com | true      | true
```

**How It Works:**
1. Customer visits `https://store.acme-corp.com/products`
2. `PlatformContextMiddleware` detects custom domain, resolves platform via `StoreDomain` lookup
3. Middleware rewrites path: `/products` → `/storefront/products` (internal)
4. `store_context_middleware` detects custom domain, queries `store_domains` table
5. Finds `StoreDomain` with `store_id = 1`, joins to get `Store(ACME Store)`
6. Rest is same as subdomain mode...

**Advantages:**
- Professional branding with store's own domain
- Better for premium stores
- Store controls the domain

**Considerations:**
- Each store needs their own SSL certificate
- Store must own and configure the domain

---

### 3. PATH-BASED MODE (Development Only)

**URL Pattern:** `http://localhost:PORT/platforms/PLATFORM_CODE/storefront/STORE_CODE/...`

**Example:**
- Development: `http://localhost:8000/platforms/oms/storefront/ACME/products`
- With port: `http://localhost:8000/platforms/loyalty/storefront/ACME/cart`

**How It Works:**
1. Developer visits `http://localhost:8000/platforms/oms/storefront/ACME/products`
2. `PlatformContextMiddleware` detects `/platforms/oms/` prefix, sets platform context, strips prefix
3. `store_context_middleware` detects `/storefront/ACME/...` pattern, extracts store code `"ACME"`
4. Looks up Store: `SELECT * FROM stores WHERE store_code = 'ACME'`
5. Sets `request.state.store = Store(ACME)`
6. Routes to storefront pages

**Advantages:**
- Perfect for local development
- No need to configure DNS/domains
- Test multiple stores and platforms easily without domain setup

**Limitations:**
- Only for development (not production-ready)
- All stores share same localhost address

---

## Complete Route Examples

### Subdomain/Custom Domain (PRODUCTION)
```
Storefront (customer-facing):
https://acme.omsflow.lu/                        → Homepage
https://acme.omsflow.lu/products                → Product Catalog
https://acme.omsflow.lu/products/123            → Product Detail
https://acme.omsflow.lu/categories/electronics  → Category Page
https://acme.omsflow.lu/cart                    → Shopping Cart
https://acme.omsflow.lu/checkout                → Checkout
https://acme.omsflow.lu/search?q=laptop         → Search Results
https://acme.omsflow.lu/account/login           → Customer Login
https://acme.omsflow.lu/account/dashboard       → Account Dashboard (Auth Required)
https://acme.omsflow.lu/account/orders          → Order History (Auth Required)

Store Dashboard (staff):
https://acme.omsflow.lu/store/dashboard         → Staff Dashboard (Auth Required)
https://acme.omsflow.lu/store/products          → Manage Products
https://acme.omsflow.lu/store/orders            → Manage Orders
https://acme.omsflow.lu/store/login             → Staff Login

Per-platform subdomain override:
https://wizatech-rewards.rewardflow.lu/         → Same store as wizatech.omsflow.lu
https://wizatech-rewards.rewardflow.lu/store/dashboard → Staff dashboard on loyalty platform
```

Note: In production, the root path `/` is the storefront. The `PlatformContextMiddleware`
internally rewrites paths to `/storefront/` for route matching. Staff access is at `/store/`.

### Path-Based (DEVELOPMENT)
```
http://localhost:8000/platforms/oms/storefront/ACME/                → Homepage
http://localhost:8000/platforms/oms/storefront/ACME/products        → Products
http://localhost:8000/platforms/oms/storefront/ACME/products/123    → Product Detail
http://localhost:8000/platforms/oms/storefront/ACME/cart            → Cart
http://localhost:8000/platforms/oms/storefront/ACME/checkout        → Checkout
http://localhost:8000/platforms/oms/storefront/ACME/account/login   → Login
```

### API Endpoints (Same for All Modes)
```
GET  /api/v1/storefront/products              → Get store products (store from middleware)
GET  /api/v1/storefront/products/123          → Get product details
POST /api/v1/storefront/products/{id}/reviews → Add product review
```

---

## How Store Isolation Works

### Multi-Layer Enforcement

**Layer 1: URL Routing**
- Store is detected from subdomain, custom domain, or path
- Each store gets their own request context

**Layer 2: Middleware**
- `request.state.store` is set to the detected Store object
- All downstream code can access the store

**Layer 3: Database Queries**
- All queries must include `WHERE store_id = ?`
- Product queries: `SELECT * FROM products WHERE store_id = 1`
- Order queries: `SELECT * FROM orders WHERE store_id = 1`

**Layer 4: API Authorization**
- Endpoints verify the store matches the request store
- Customers can only see their own store's products

### Example: No Cross-Store Leakage
```python
# Customer on acme.omsflow.lu tries to access TechPro's products
# Store context is set to ACME by middleware — all queries scoped to ACME

# Backend checks:
store = get_store_from_request(request)  # Returns Store(id=1, name="ACME")
if store.id != requested_store_id:       # if 1 != 2
    raise UnauthorizedStorefrontAccessException()
```

---

## Request Lifecycle: Complete Flow

### Scenario: Customer visits `https://acme.orion.lu/storefront/products`

```
┌─────────────────────────────────────────────────────────────────┐
│ 1. REQUEST ARRIVES                                              │
└─────────────────────────────────────────────────────────────────┘
   method: GET
   host: acme.orion.lu
   path: /storefront/products

┌─────────────────────────────────────────────────────────────────┐
│ 2. MIDDLEWARE CHAIN                                             │
└─────────────────────────────────────────────────────────────────┘

   A) store_context_middleware
      ├─ Detects host: "acme.orion.lu"
      ├─ Extracts subdomain: "acme"
      ├─ Queries: SELECT * FROM stores WHERE subdomain = 'acme'
      └─ Sets: request.state.store = Store(ACME Store)

   B) context_middleware
      ├─ Checks path: "/storefront/products"
      ├─ Has request.state.store? YES
      └─ Sets: request.state.context_type = RequestContext.STOREFRONT

   C) theme_context_middleware
      ├─ Queries: SELECT * FROM store_themes WHERE store_id = 1
      └─ Sets: request.state.theme = {...ACME's theme...}

┌─────────────────────────────────────────────────────────────────┐
│ 3. ROUTE MATCHING                                               │
└─────────────────────────────────────────────────────────────────┘
   Path: /storefront/products
   Matches: @router.get("/storefront/products")
   Handler: storefront_products_page(request)

┌─────────────────────────────────────────────────────────────────┐
│ 4. HANDLER EXECUTES                                             │
└─────────────────────────────────────────────────────────────────┘
   @router.get("/storefront/products", response_class=HTMLResponse)
   async def storefront_products_page(request: Request):
       return templates.TemplateResponse(
           "storefront/products.html",
           {"request": request}
       )

┌─────────────────────────────────────────────────────────────────┐
│ 5. TEMPLATE RENDERS                                             │
└─────────────────────────────────────────────────────────────────┘
   Template accesses:
   ├─ request.state.store.name → "ACME Store"
   ├─ request.state.theme.colors.primary → "#FF6B6B"
   ├─ request.state.theme.branding.logo → "acme-logo.png"
   └─ Products will load via JavaScript API call

┌─────────────────────────────────────────────────────────────────┐
│ 6. JAVASCRIPT LOADS PRODUCTS (Client-Side)                     │
└─────────────────────────────────────────────────────────────────┘
   fetch(`/api/v1/storefront/stores/1/products`)
   .then(data => renderProducts(data.products, {theme}))

┌─────────────────────────────────────────────────────────────────┐
│ 7. RESPONSE SENT                                                │
└─────────────────────────────────────────────────────────────────┘
   HTML with ACME's colors, logo, and products
```

---

## Theme Integration

Each store's storefront is fully branded with their custom theme:

```python
# Theme loaded for https://acme.orion.lu
request.state.theme = {
    "theme_name": "modern",
    "colors": {
        "primary": "#FF6B6B",
        "secondary": "#FF8787",
        "accent": "#FF5252",
        "background": "#ffffff",
        "text": "#1f2937"
    },
    "branding": {
        "logo": "acme-logo.png",
        "favicon": "acme-favicon.ico",
        "banner": "acme-banner.jpg"
    },
    "fonts": {
        "heading": "Poppins, sans-serif",
        "body": "Inter, sans-serif"
    }
}
```

In Jinja2 template:
```html
<style>
  :root {
    --color-primary: {{ request.state.theme.colors.primary }};
    --color-secondary: {{ request.state.theme.colors.secondary }};
  }
</style>

<img src="{{ request.state.theme.branding.logo }}" alt="{{ request.state.store.name }}" />
<h1 style="font-family: {{ request.state.theme.fonts.heading }}">
  Welcome to {{ request.state.store.name }}
</h1>
```

---

## Key Points for Understanding

### 1. Customer Perspective
- Customers just visit a URL (like any normal e-commerce site)
- They have no awareness it's a multi-tenant platform
- Each store looks completely separate and branded

### 2. Store Perspective
- Stores can use a subdomain (free/standard): `acme.orion.lu`
- Or their own custom domain (premium): `store.acme-corp.com`
- Both routes go to the exact same backend code

### 3. Developer Perspective
- The middleware layer detects which store is being accessed
- All business logic remains store-unaware
- Database queries automatically filtered by store
- No risk of data leakage because of multi-layer isolation

### 4. Tech Stack
- **Frontend:** Jinja2 templates + Alpine.js + Tailwind CSS
- **Backend:** FastAPI + SQLAlchemy
- **Auth:** JWT with store-scoped cookies
- **Database:** All tables have `store_id` foreign key

---

## Path-Based Routing Implementation

**Current Solution: Double Router Mounting + Path Rewriting**

The application handles routing by registering both storefront and store dashboard routes **twice** with different prefixes:

```python
# In main.py — Storefront routes (customer-facing)
app.include_router(storefront_pages.router, prefix="/storefront")
app.include_router(storefront_pages.router, prefix="/storefront/{store_code}")

# In main.py — Store dashboard routes (staff management)
app.include_router(store_pages.router, prefix="/store")
app.include_router(store_pages.router, prefix="/store/{store_code}")
```

**How This Works:**

1. **For Subdomain/Custom Domain Mode (Production):**
   - Storefront: `https://acme.omsflow.lu/products` → path rewritten to `/storefront/products` → matches first storefront mount
   - Dashboard: `https://acme.omsflow.lu/store/dashboard` → matches first store mount at `/store`
   - Store resolved by middleware via `request.state.store`

2. **For Path-Based Development Mode:**
   - Storefront: `http://localhost:8000/platforms/oms/storefront/ACME/products` → matches second storefront mount at `/storefront/{store_code}`
   - Dashboard: `http://localhost:8000/platforms/oms/store/ACME/dashboard` → matches second store mount at `/store/{store_code}`
   - `store_code` available as path parameter

### `get_resolved_store_code` Dependency

Route handlers use the `get_resolved_store_code` dependency to transparently obtain the store code regardless of deployment mode:

```python
async def get_resolved_store_code(request: Request) -> str:
    # 1. Path parameter from double-mount (/store/{store_code}/...)
    store_code = request.path_params.get("store_code")
    if store_code:
        return store_code
    # 2. Middleware-resolved store (subdomain or custom domain)
    store = getattr(request.state, "store", None)
    if store:
        return store.store_code
    raise HTTPException(status_code=404, detail="Store not found")
```

**Benefits:**
- ✅ Clean separation: `/storefront/` = customer, `/store/` = staff
- ✅ Production URLs are clean (root path = storefront)
- ✅ No `/storefront/` prefix visible to production customers
- ✅ Internal path rewriting handled by ASGI middleware
- ✅ Both deployment modes supported cleanly
- ✅ `get_resolved_store_code` abstracts store resolution for handlers

---

## Per-Platform Subdomain Overrides

Stores that are active on multiple platforms can have a **custom subdomain** per platform via `StorePlatform.custom_subdomain`. This allows a single store to appear under different subdomains on different platform domains.

### How It Works

```
Store: WizaTech (subdomain: "wizatech")
├── OMS platform  → wizatech.omsflow.lu         (uses Store.subdomain)
└── Loyalty platform → wizatech-rewards.rewardflow.lu  (uses StorePlatform.custom_subdomain)
```

**Database:**
```sql
-- stores table
id | store_code | subdomain
1  | WIZATECH   | wizatech

-- store_platforms table
id | store_id | platform_id | custom_subdomain
1  | 1        | 1 (oms)     | NULL                  -- uses store.subdomain = "wizatech"
2  | 1        | 2 (loyalty) | wizatech-rewards      -- overrides to "wizatech-rewards"
```

**Resolution order** (in `store_context_middleware`):
1. Check `StorePlatform.custom_subdomain` for a match on the current platform
2. Fall back to `Store.subdomain` for the standard lookup

### Use Cases

- **Brand differentiation**: A store selling electronics via OMS and running a loyalty program wants different branding per platform
- **Subdomain conflicts**: Two unrelated stores might use the same subdomain on different platforms — custom subdomains resolve the collision
- **Marketing**: Platform-specific landing URLs for campaigns (e.g., `wizatech-rewards.rewardflow.lu` for loyalty-specific promotions)

---

## Authentication in Multi-Tenant Storefront

Customer authentication uses store-scoped cookies:

```python
# Login sets cookie scoped to store's storefront
Set-Cookie: customer_token=eyJ...; Path=/storefront; HttpOnly; SameSite=Lax

# This prevents:
# - Tokens leaking across stores
# - Cross-site request forgery
# - Cookie scope confusion in multi-tenant setup
```

---

## Summary Table

| Mode | URL | Use Case | SSL | DNS |
|------|-----|----------|-----|-----|
| Subdomain | `store.platform.com/` | Production (standard) | *.platform.com | Add subdomains |
| Custom Domain | `store-domain.com/` | Production (premium) | Per store | Store configures |
| Path-Based | `localhost:8000/platforms/{p}/storefront/{v}/` | Development only | None | None |

---

## Next Steps

1. **For Production:** Use subdomain or custom domain mode
2. **For Development:** Use path-based mode locally
3. **For Deployment:** Configure DNS for subdomains or custom domains
4. **For Testing:** Create test stores with different themes
5. **For Scaling:** Consider CDN for store-specific assets

---

Generated: February 26, 2026
Orion Version: Current Development