berrypod/docs/plans/products-context.md

# Plan: Products Context with Provider Integration

> **Status:** Phase 1 Complete (c5c06d9) - See [PROGRESS.md](../../PROGRESS.md) for current status.

## Goal
Build a Products context that syncs products from external POD providers (Printify first), stores them locally, and enables order submission for fulfillment.

## Core Flow
1. **Connect** - Authenticate with provider (API key or OAuth)
2. **Sync** - Fetch products from provider, upsert locally
3. **Order** - Submit orders to provider for fulfillment

---

## Current Domain Analysis

SimpleShop has **6 well-defined domains** with clear boundaries:

| Domain | Purpose | Schemas | Public Functions |
|--------|---------|---------|------------------|
| **Accounts** | User authentication & sessions | User, UserToken | 15 |
| **Settings** | Theme configuration persistence | Setting, ThemeSettings | 6 |
| **Theme** | CSS generation, caching, presets | (structs only) | N/A |
| **Media** | Image upload/storage | Image | 8 |
| **Images** | Image optimization pipeline | (Oban workers) | N/A |
| **Printify** | External API integration | (no schemas) | API client |

The new **Products** context will be a new top-level domain that:
- Owns product/variant schemas
- Coordinates with Printify (and future providers) for sync
- Provides data to shop LiveViews (replacing PreviewData)

---

## Architecture Diagram

```
┌─────────────────────────────────────────────────────────────────────────────┐
│                              SimpleshopTheme                                 │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                              │
│  ┌──────────────────────────────────────────────────────────────────────┐   │
│  │                         WEB LAYER                                     │   │
│  │  SimpleshopThemeWeb                                                   │   │
│  │  ┌────────────────┐  ┌────────────────┐  ┌─────────────────────────┐ │   │
│  │  │  Shop LiveViews │  │ Admin LiveViews│  │ Theme Editor LiveView  │ │   │
│  │  │  - ProductShow  │  │ - UserLogin    │  │ - ThemeLive.Index      │ │   │
│  │  │  - Collection   │  │ - UserSettings │  │ - Preview iframe       │ │   │
│  │  │  - Cart         │  │                │  │                        │ │   │
│  │  └───────┬─────────┘  └────────────────┘  └────────┬───────────────┘ │   │
│  └──────────┼────────────────────────────────────────┼──────────────────┘   │
│             │                                         │                      │
│             ▼                                         ▼                      │
│  ┌──────────────────────────────────────────────────────────────────────┐   │
│  │                       DOMAIN LAYER                                    │   │
│  │                                                                       │   │
│  │  ┌─────────────┐   ┌─────────────┐   ┌─────────────┐                 │   │
│  │  │  Accounts   │   │  Settings   │   │    Theme    │                 │   │
│  │  │             │   │             │   │             │                 │   │
│  │  │ • User      │   │ • Setting   │   │ • CSSCache  │                 │   │
│  │  │ • UserToken │   │ • Theme     │   │ • CSSGen    │                 │   │
│  │  │             │   │   Settings  │   │ • Presets   │                 │   │
│  │  │             │   │             │   │ • Fonts     │                 │   │
│  │  │             │   │             │   │ • Preview   │                 │   │
│  │  └─────────────┘   └──────┬──────┘   │   Data (*)  │                 │   │
│  │                           │          └─────────────┘                 │   │
│  │                           │                                          │   │
│  │  ┌─────────────┐   ┌──────▼──────┐   ┌─────────────┐                 │   │
│  │  │    Media    │   │   Images    │   │  Printify   │                 │   │
│  │  │             │   │             │   │             │                 │   │
│  │  │ • Image     │◄──│ • Optimizer │   │ • Client    │                 │   │
│  │  │   (upload)  │   │ • Worker    │   │ • Catalog   │ (NEW)           │   │
│  │  │             │   │ • Cache     │   │ • Mockup    │                 │   │
│  │  └─────────────┘   └─────────────┘   └──────┬──────┘                 │   │
│  │                                              │                        │   │
│  │  ┌───────────────────────────────────────────▼───────────────────┐   │   │
│  │  │                    Products (NEW)                              │   │   │
│  │  │                                                                │   │   │
│  │  │  ┌─────────────────────┐    ┌────────────────────────────┐    │   │   │
│  │  │  │  Provider Layer     │    │  Product Layer              │    │   │   │
│  │  │  │                     │    │                             │    │   │   │
│  │  │  │ • ProviderConnection│───▶│ • Product                   │    │   │   │
│  │  │  │ • Provider behaviour│    │ • ProductImage              │    │   │   │
│  │  │  │ • PrintifyProvider  │    │ • ProductVariant            │    │   │   │
│  │  │  │ • (future providers)│    │                             │    │   │   │
│  │  │  └─────────────────────┘    └────────────────────────────┘    │   │   │
│  │  │                                                                │   │   │
│  │  │  ┌─────────────────────────────────────────────────────────┐  │   │   │
│  │  │  │  Sync Layer                                              │  │   │   │
│  │  │  │  • ProductSyncWorker (Oban)                              │  │   │   │
│  │  │  │  • Upsert logic                                          │  │   │   │
│  │  │  └─────────────────────────────────────────────────────────┘  │   │   │
│  │  └────────────────────────────────────────────────────────────────┘   │   │
│  │                                                                       │   │
│  │  ┌────────────────────────────────────────────────────────────────┐   │   │
│  │  │                     Orders (NEW)                                │   │   │
│  │  │                                                                 │   │   │
│  │  │  • Order           • submit_to_provider/1                       │   │   │
│  │  │  • OrderLineItem   • track_status/1                             │   │   │
│  │  └────────────────────────────────────────────────────────────────┘   │   │
│  │                                                                       │   │
│  └───────────────────────────────────────────────────────────────────────┘   │
│                                                                              │
│  ┌───────────────────────────────────────────────────────────────────────┐   │
│  │                       INFRASTRUCTURE                                   │   │
│  │   Repo (SQLite)  •  Vault (encryption)  •  Oban (background jobs)     │   │
│  └───────────────────────────────────────────────────────────────────────┘   │
│                                                                              │
└─────────────────────────────────────────────────────────────────────────────┘

(*) PreviewData will be replaced by Products context queries
```

---

## Database ERD

```
┌─────────────────────────────────────────────────────────────────────────────┐
│                            CURRENT SCHEMA                                    │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                              │
│  ┌──────────────────┐         ┌──────────────────┐                          │
│  │      users       │         │   users_tokens   │                          │
│  ├──────────────────┤         ├──────────────────┤                          │
│  │ id (binary_id)   │◄────────│ user_id (FK)     │                          │
│  │ email            │         │ token            │                          │
│  │ hashed_password  │         │ context          │                          │
│  │ confirmed_at     │         │ sent_to          │                          │
│  │ inserted_at      │         │ inserted_at      │                          │
│  │ updated_at       │         └──────────────────┘                          │
│  └──────────────────┘                                                        │
│                                                                              │
│  ┌──────────────────┐         ┌──────────────────┐                          │
│  │    settings      │         │     images       │                          │
│  ├──────────────────┤         ├──────────────────┤                          │
│  │ id (binary_id)   │         │ id (binary_id)   │                          │
│  │ key              │         │ filename         │                          │
│  │ value (JSON)     │         │ content_type     │                          │
│  │ inserted_at      │         │ byte_size        │                          │
│  │ updated_at       │         │ width            │                          │
│  └──────────────────┘         │ height           │                          │
│                               │ storage_key      │                          │
│                               │ inserted_at      │                          │
│                               │ updated_at       │                          │
│                               └──────────────────┘                          │
├─────────────────────────────────────────────────────────────────────────────┤
│                            NEW SCHEMA (Products)                             │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                              │
│  ┌────────────────────────┐                                                  │
│  │  provider_connections  │                                                  │
│  ├────────────────────────┤                                                  │
│  │ id (binary_id)         │                                                  │
│  │ provider_type          │──┐  "printify" | "prodigi" | "gelato"           │
│  │ name                   │  │                                               │
│  │ enabled                │  │                                               │
│  │ api_key_encrypted      │  │  (Vault encrypted)                           │
│  │ config (JSON)          │  │  {"shop_id": "123"}                          │
│  │ last_synced_at         │  │                                               │
│  │ sync_status            │  │                                               │
│  │ inserted_at            │  │                                               │
│  │ updated_at             │  │                                               │
│  └───────────┬────────────┘  │                                               │
│              │               │                                               │
│              │ 1             │                                               │
│              ▼ *             │                                               │
│  ┌────────────────────────┐  │                                               │
│  │       products         │  │                                               │
│  ├────────────────────────┤  │                                               │
│  │ id (binary_id)         │  │                                               │
│  │ provider_connection_id │◄─┘                                               │
│  │ provider_product_id    │     External ID (unique per connection)         │
│  │ title                  │                                                  │
│  │ description            │                                                  │
│  │ slug                   │     URL-friendly (unique globally)              │
│  │ status                 │     "active" | "draft" | "archived"             │
│  │ visible                │                                                  │
│  │ category               │                                                  │
│  │ option_types (JSON)    │     ["size", "color"] - display order           │
│  │ provider_data (JSON)   │     Provider-specific fields (blueprint_id etc) │
│  │ inserted_at            │                                                  │
│  │ updated_at             │                                                  │
│  └───────────┬────────────┘                                                  │
│              │                                                               │
│              │ 1                                                             │
│    ┌─────────┴─────────┐                                                     │
│    ▼ *                 ▼ *                                                   │
│  ┌──────────────────┐  ┌──────────────────────┐                             │
│  │  product_images  │  │  product_variants    │                             │
│  ├──────────────────┤  ├──────────────────────┤                             │
│  │ id (binary_id)   │  │ id (binary_id)       │                             │
│  │ product_id (FK)  │  │ product_id (FK)      │                             │
│  │ src              │  │ provider_variant_id  │                             │
│  │ position         │  │ title                │  "Large / Black"            │
│  │ alt              │  │ sku                  │                             │
│  │ inserted_at      │  │ price                │  Selling price (pence)      │
│  │ updated_at       │  │ compare_at_price     │  For sale display           │
│  └──────────────────┘  │ cost                 │  Provider cost (profit)     │
│                        │ options (JSON)       │  {"size": "L", "color": ""}  │
│                        │ is_enabled           │                             │
│                        │ is_available         │                             │
│                        │ inserted_at          │                             │
│                        │ updated_at           │                             │
│                        └──────────────────────┘                             │
│                                                                              │
├─────────────────────────────────────────────────────────────────────────────┤
│                            NEW SCHEMA (Orders)                               │
│                                                                              │
│  Customer sees ONE order. Fulfillments are internal (one per provider).     │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                              │
│  ┌────────────────────────┐                                                  │
│  │        orders          │    Customer-facing order                        │
│  ├────────────────────────┤                                                  │
│  │ id (binary_id)         │                                                  │
│  │ order_number           │    "SS-250125-A1B2" (customer sees this)        │
│  │ status                 │    pending → processing → shipped → delivered   │
│  │ payment_status         │    pending | paid | refunded                    │
│  │ customer_email         │                                                  │
│  │ shipping_address (JSON)│                                                  │
│  │ subtotal               │    (Money - ex_money)                           │
│  │ shipping_cost          │    (Money - ex_money)                           │
│  │ total                  │    (Money - ex_money)                           │
│  │ total_cost             │    Provider costs (for profit)                  │
│  │ inserted_at            │                                                  │
│  │ updated_at             │                                                  │
│  └───────────┬────────────┘                                                  │
│              │                                                               │
│              │ 1                                                             │
│    ┌─────────┴─────────────────────────┐                                     │
│    ▼ *                                 ▼ *                                   │
│  ┌────────────────────────┐  ┌─────────────────────────┐                    │
│  │  order_fulfillments    │  │   order_line_items      │                    │
│  ├────────────────────────┤  ├─────────────────────────┤                    │
│  │ id (binary_id)         │  │ id (binary_id)          │                    │
│  │ order_id (FK)          │  │ order_id (FK)           │                    │
│  │ provider_connection_id │  │ order_fulfillment_id(FK)│ Which provider     │
│  │ provider_order_id      │  │ product_variant_id (FK) │                    │
│  │ status                 │  │ quantity                │                    │
│  │ tracking_number        │  │ unit_price              │                    │
│  │ tracking_url           │  │ unit_cost               │                    │
│  │ shipped_at             │  │ inserted_at             │                    │
│  │ inserted_at            │  │ updated_at              │                    │
│  │ updated_at             │  └─────────────────────────┘                    │
│  └────────────────────────┘                                                  │
│                                                                              │
│  ┌────────────────────────┐                                                  │
│  │    order_events        │    Timeline visible to customer                 │
│  ├────────────────────────┤                                                  │
│  │ id (binary_id)         │                                                  │
│  │ order_id (FK)          │                                                  │
│  │ type                   │    "placed" | "paid" | "shipped" | "delivered"  │
│  │ message                │    "Your T-Shirt has shipped via Royal Mail"   │
│  │ metadata (JSON)        │    {tracking_number, carrier, etc}              │
│  │ inserted_at            │                                                  │
│  └────────────────────────┘                                                  │
│                                                                              │
└─────────────────────────────────────────────────────────────────────────────┘
```

---

## Printify Code Reuse

### Existing Client (Highly Reusable)

The existing `Printify.Client` is directly reusable:

```elixir
# HTTP infrastructure (no changes needed)
Client.get/2, Client.post/3, Client.delete/2

# Shop management
Client.get_shops/0, Client.get_shop_id/0

# Product operations (already implemented)
Client.get_product/2, Client.create_product/2, Client.delete_product/2
```

**To add:**
```elixir
Client.list_products/1  # GET /shops/:shop_id/products.json
Client.create_order/2   # POST /shops/:shop_id/orders.json
Client.get_order/2      # GET /shops/:shop_id/orders/:id.json
```

### MockupGenerator Refactoring

Extract reusable helpers into new `Printify.Catalog` module:

| Function | Current | Target |
|----------|---------|--------|
| `find_blueprint/1` | MockupGenerator | `Printify.Catalog` |
| `find_print_provider/2` | MockupGenerator | `Printify.Catalog` |
| `get_variant_info/1` | MockupGenerator | `Printify.Catalog` |
| `calculate_cover_scale/2` | MockupGenerator | Keep (mockup-specific) |
| `product_definitions/0` | MockupGenerator | Keep (sample data) |

**Module structure:**
```
lib/simpleshop_theme/clients/
├── printify.ex         # Printify HTTP client (moved from printify/client.ex)
├── gelato.ex           # Gelato HTTP client
└── prodigi.ex          # Prodigi HTTP client

lib/simpleshop_theme/providers/
├── provider.ex         # Behaviour definition
├── printify.ex         # Printify implementation (uses Clients.Printify)
├── gelato.ex           # Gelato implementation (uses Clients.Gelato)
└── prodigi.ex          # Prodigi implementation (uses Clients.Prodigi)

lib/simpleshop_theme/mockups/
└── generator.ex        # Mockup generation (currently uses Clients.Printify)
                        # Provider-agnostic location for future flexibility

lib/simpleshop_theme/printify/
└── catalog.ex          # Blueprint/variant discovery helpers (Printify-specific)
```

Each provider module uses its corresponding client. The mockup generator is in a provider-agnostic location.

---

## Database Schema

### Tables Overview

| Table | Purpose |
|-------|---------|
| `provider_connections` | Provider credentials + config (one per type) |
| `products` | Core product data synced from provider |
| `product_images` | Product images (multiple per product) |
| `product_variants` | Size/color variants with pricing |
| `orders` | Customer orders |
| `order_line_items` | Items within orders |

### Key Design Decisions

1. **Provider IDs on product directly** (not a separate linking table)
   - `products.provider_product_id` stores external ID
   - `product_variants.provider_variant_id` stores external variant ID
   - Unique constraint: `[:provider_connection_id, :provider_product_id]`

2. **Credentials encrypted in database**
   - Use `SimpleshopTheme.Vault` for at-rest encryption
   - `api_key_encrypted`, `oauth_access_token_encrypted` fields

3. **Cost tracking for profit calculation**
   - `product_variants.cost` - cost from provider
   - `order_line_items.unit_cost` - snapshot at order time
   - `orders.total_cost` - sum for profit reporting

4. **Provider type as enum** (not separate table)
   - Hardcoded: `~w(printify prodigi gelato)`
   - Keeps type safety for provider-specific logic

---

## Schema Details

### provider_connections
```elixir
field :provider_type, :string       # "printify", "prodigi", "gelato"
field :name, :string                # "My Printify Account"
field :enabled, :boolean
field :api_key_encrypted, :binary   # Encrypted API key
field :config, :map                 # {"shop_id": "12345"}
field :last_synced_at, :utc_datetime
field :sync_status, :string         # pending, syncing, completed, failed
```

### products
```elixir
belongs_to :provider_connection
field :provider_product_id, :string  # External ID from provider
field :title, :string
field :description, :text
field :slug, :string                 # URL-friendly, unique
field :status, :string               # active, draft, archived
field :visible, :boolean
field :category, :string
field :option_types, {:array, :string}  # ["Colors", "Sizes"] - option names in display order
                                        # Extracted from provider's product.options[].name on sync
                                        # Used to order the variant selector UI
field :provider_data, :map           # Provider-specific fields stored here
                                     # Printify: %{"blueprint_id" => 145, "print_provider_id" => 29, ...}
                                     # Keeps products table generic across providers
```

### product_variants
```elixir
belongs_to :product
field :provider_variant_id, :string  # CRITICAL: The ID we send back to provider when ordering
                                     # Printify: variant_id (e.g., "12345")
                                     # Printful: sync_variant_id (e.g., "4752058849")
                                     # Gelato: productUid (e.g., "apparel_product_gca_t-shirt_gsi_m_gco_white")
                                     # Prodigi: sku (e.g., "GLOBAL-CAN-10x10")
field :title, :string                # "Large / Black"
field :sku, :string                  # Shop's internal SKU (optional)
field :price, :integer               # Selling price (pence)
field :compare_at_price, :integer    # Original price (for sales)
field :cost, :integer                # Provider cost (for profit)
field :options, :map                 # {"size": "Large", "color": "Black"}
                                     # JSON is appropriate here because:
                                     # - Options always loaded with variant (no join needed)
                                     # - No need to query "find all Large variants"
                                     # - Matches provider data format (easy sync)
                                     # - Simpler than a separate options table
field :is_enabled, :boolean
field :is_available, :boolean        # In stock at provider
```

### orders (customer-facing)
```elixir
# Customer sees ONE order, even if fulfilled by multiple providers
field :order_number, :string         # "SS-250125-A1B2" (customer-visible)
field :status, :string               # Aggregate: pending → processing → shipped → delivered
field :payment_status, :string       # pending, paid, refunded
field :customer_email, :string
field :shipping_address, :map
field :subtotal, Money.Ecto.Map.Type # Using ex_money for currency safety
field :shipping_cost, Money.Ecto.Map.Type
field :total, Money.Ecto.Map.Type
field :total_cost, Money.Ecto.Map.Type  # Sum of provider costs

has_many :order_fulfillments         # One per provider
has_many :order_line_items
has_many :order_events               # Timeline for customer
```

### order_fulfillments (one per provider)
```elixir
belongs_to :order
belongs_to :provider_connection
field :provider_order_id, :string    # External ID after submission
field :status, :string               # pending → submitted → processing → shipped
field :tracking_number, :string
field :tracking_url, :string
field :shipped_at, :utc_datetime

has_many :order_line_items           # Items fulfilled by this provider
```

### order_line_items
```elixir
belongs_to :order
belongs_to :order_fulfillment        # Links to which provider ships this item
belongs_to :product_variant
field :quantity, :integer
field :unit_price, Money.Ecto.Map.Type
field :unit_cost, Money.Ecto.Map.Type

# Per-item tracking (provider may ship items separately)
field :status, :string               # pending → shipped → delivered
field :tracking_number, :string
field :tracking_url, :string
field :shipped_at, :utc_datetime
```

### order_events (customer timeline)
```elixir
belongs_to :order
field :type, :string                 # Event types (see below)
field :message, :string              # "Your T-Shirt and Mug have shipped!"
field :metadata, :map                # {tracking_number, carrier, items, etc}

# Event types:
# - "placed"              → Order placed
# - "paid"                → Payment confirmed
# - "fulfillment_shipped" → Some items shipped (granular per-fulfillment)
# - "shipped"             → ALL items now shipped
# - "delivered"           → ALL items delivered

# Example metadata for fulfillment_shipped:
# %{fulfillment_id: "uuid", items: ["T-Shirt", "Mug"],
#   carrier: "Royal Mail", tracking_number: "RM123", tracking_url: "..."}
```

---

## Variant Selector UX Pattern

Products with multiple option types (e.g., size × color × sleeves) can have many variants:
- 4 sizes × 4 colors × 2 sleeves = **32 variants**

### Data Model

Each variant stores its specific combination as JSON with **human-readable labels**:
```elixir
%{id: "v1", options: %{"size" => "M", "color" => "Black", "sleeves" => "Short"}, price: 2500}
%{id: "v2", options: %{"size" => "M", "color" => "Black", "sleeves" => "Long"}, price: 2700}
# ... etc
```

### Provider Option Structure (Important)

Providers like Printify use a **two-tier option system**:

**Product level** - defines options with IDs and labels:
```json
{
  "options": [
    { "name": "Colors", "type": "color", "values": [
      { "id": 751, "title": "Solid White" },
      { "id": 752, "title": "Black" }
    ]},
    { "name": "Sizes", "type": "size", "values": [
      { "id": 2, "title": "S" },
      { "id": 3, "title": "M" }
    ]}
  ]
}
```

**Variant level** - only stores option IDs:
```json
{ "id": 12345, "options": [751, 2], "title": "Solid White / S" }
```

### Sync Strategy: Denormalize to Labels

During sync, we **resolve IDs to labels** and store the human-readable version:

```elixir
def normalize_variant(provider_variant, product_options) do
  # Build ID -> label lookup from product options
  option_lookup = build_option_lookup(product_options)
  # => %{751 => {"Colors", "Solid White"}, 2 => {"Sizes", "S"}}

  # Convert variant's [751, 2] to %{"Colors" => "Solid White", "Sizes" => "S"}
  options =
    provider_variant["options"]
    |> Enum.map(&Map.get(option_lookup, &1))
    |> Enum.reject(&is_nil/1)
    |> Map.new()

  %{
    provider_variant_id: to_string(provider_variant["id"]),
    title: provider_variant["title"],
    options: options,
    # ... other fields
  }
end
```

**Why denormalize?**
- No need to join to an options table on every product page load
- Labels rarely change (and if they do, re-sync updates them)
- Simpler queries, faster rendering
- Keeps our schema provider-agnostic (we just store labels, not provider-specific IDs)

### Provider Compatibility

All major POD providers can be normalized to our `options: %{"Size" => "M", "Color" => "Black"}` schema:

| Provider | Raw Variant Structure | Normalization |
|----------|----------------------|---------------|
| **Printify** | `options: [751, 2]` (IDs only, labels at product level) | Resolve IDs → labels during sync |
| **Printful** | `color: "Black", size: "M"` (flat attributes) | Map attribute keys to standard names |
| **Gelato** | `variantOptions: [{name: "Size", value: "M"}]` (array) | Convert array to map |
| **Prodigi** | `attributes: {"wrap": "Black"}` (object) | Direct mapping |

Each provider's `normalize_variant/2` function handles the transformation:

```elixir
# Printify - resolve IDs to labels
%{"options" => [751, 2]} → %{"Colors" => "Solid White", "Sizes" => "S"}

# Printful - rename keys
%{"color" => "Black", "size" => "M"} → %{"Color" => "Black", "Size" => "M"}

# Gelato - array to map
[%{"name" => "Size", "value" => "M"}] → %{"Size" => "M"}

# Prodigi - direct (already a map)
%{"wrap" => "Black"} → %{"Wrap" => "Black"}
```

Sources:
- [Printful API Documentation](https://developers.printful.com/docs/)
- [Gelato API - Get Template](https://dashboard.gelato.com/docs/ecommerce/templates/get/)
- [Prodigi API Documentation](https://www.prodigi.com/print-api/docs/reference/)

### Why JSON Options Work Well

| Use Case | Query Pattern | Efficient? |
|----------|---------------|------------|
| Product page - list variants | `where(product_id: ^id)` | Yes - no JSON query |
| Cart - get variant by ID | `Repo.get(Variant, id)` | Yes - no JSON query |
| Display options on page | Access `variant.options` | Yes - in-memory map |
| Find matching variant | `Enum.find` on loaded list | Yes - all variants loaded anyway |

A separate `variant_options` table would add joins and complexity without benefit.

### LiveView Implementation

**On mount**, load product with all variants and extract option types:
```elixir
def mount(_params, _session, socket) do
  product = Products.get_product_with_variants(slug)

  # Extract unique option names and values from variants
  option_types = extract_option_types(product.variants)
  # => %{
  #   "size" => ["S", "M", "L", "XL"],
  #   "color" => ["Black", "Green", "Blue", "Grey"],
  #   "sleeves" => ["Short", "Long"]
  # }

  {:ok, assign(socket, product: product, option_types: option_types, selected: %{})}
end

defp extract_option_types(variants) do
  variants
  |> Enum.flat_map(fn v -> Map.to_list(v.options) end)
  |> Enum.group_by(&elem(&1, 0), &elem(&1, 1))
  |> Map.new(fn {k, v} -> {k, Enum.uniq(v)} end)
end
```

### Cascading Selector UI

Standard e-commerce pattern with availability filtering:

```
┌─────────────────────────────────────┐
│  Size:    [S] [M] [L] [XL]          │  ← User selects "M"
├─────────────────────────────────────┤
│  Color:   [Black] [Green] [Blue]    │  ← Grey disabled (no M+Grey combo)
├─────────────────────────────────────┤
│  Sleeves: [Short] [Long]            │  ← User selects "Long"
├─────────────────────────────────────┤
│  Price: £27.00                      │
│  [Add to Cart]                      │  ← Adds variant "M/Black/Long"
└─────────────────────────────────────┘
```

**Key behaviors:**
1. User selects options one at a time
2. Unavailable combinations are disabled/greyed out
3. Once all options selected, show matching variant's price
4. Add to cart uses the specific variant ID

### Selection Handler

```elixir
def handle_event("select_option", %{"option" => option, "value" => value}, socket) do
  selected = Map.put(socket.assigns.selected, option, value)

  # Find matching variant (if all options selected)
  current_variant = find_matching_variant(socket.assigns.product.variants, selected)

  # Determine which options are still available given current selection
  available_options = compute_available_options(socket.assigns.product.variants, selected)

  {:noreply, assign(socket,
    selected: selected,
    current_variant: current_variant,
    available_options: available_options
  )}
end

defp find_matching_variant(variants, selected) do
  Enum.find(variants, fn v -> Map.equal?(v.options, selected) end)
end

defp compute_available_options(variants, selected) do
  # For each unselected option type, find values that have
  # at least one variant matching current selection
  # (filters out impossible combinations)
end
```

### Optional: Store Option Order on Product

For consistent selector ordering, optionally store on product:
```elixir
field :option_types, {:array, :string}  # ["size", "color", "sleeves"]
```

This defines display order. Can be extracted from provider API on first sync.

---

## Provider Behaviour

```elixir
@callback provider_type() :: String.t()
@callback test_connection(conn) :: {:ok, map()} | {:error, term()}
@callback fetch_products(conn) :: {:ok, [map()]} | {:error, term()}
@callback normalize_product(raw_product) :: map()           # Transform to our schema
@callback normalize_variant(raw_variant, product) :: map()  # Transform + resolve options
@callback build_order_item(variant, quantity) :: map()      # Build provider-specific order item
@callback submit_order(conn, order) :: {:ok, %{provider_order_id: String.t()}} | {:error, term()}
@callback get_order_status(conn, provider_order_id) :: {:ok, map()} | {:error, term()}
```

Each provider (Printify, Prodigi, Gelato) implements this behaviour with provider-specific API calls and data normalization.

---

## Order Submission Flow

When submitting an order, we must send **provider-specific variant identifiers** back to each provider.

### What Each Provider Needs

| Provider | Order Item Fields Required | Source in Our Schema |
|----------|---------------------------|---------------------|
| **Printify** | `product_id`, `variant_id`, `print_provider_id` | `product.provider_product_id`, `variant.provider_variant_id`, `product.provider_data["print_provider_id"]` |
| **Printful** | `sync_variant_id` | `variant.provider_variant_id` |
| **Gelato** | `productUid`, `itemReferenceId` | `variant.provider_variant_id`, our `order_line_item.id` |
| **Prodigi** | `sku`, `attributes` | `variant.provider_variant_id`, `variant.options` |

### Provider `build_order_item/2` Examples

```elixir
# Printify
def build_order_item(variant, quantity) do
  product = variant.product
  %{
    "product_id" => product.provider_product_id,
    "variant_id" => String.to_integer(variant.provider_variant_id),
    "print_provider_id" => product.provider_data["print_provider_id"],
    "quantity" => quantity
  }
end

# Printful
def build_order_item(variant, quantity) do
  %{
    "sync_variant_id" => String.to_integer(variant.provider_variant_id),
    "quantity" => quantity
  }
end

# Gelato
def build_order_item(variant, quantity) do
  %{
    "productUid" => variant.provider_variant_id,
    "quantity" => quantity,
    "itemReferenceId" => Ecto.UUID.generate()
  }
end

# Prodigi
def build_order_item(variant, quantity) do
  %{
    "sku" => variant.provider_variant_id,
    "copies" => quantity,
    "attributes" => variant.options  # {"wrap" => "Black"} etc.
  }
end
```

### Order Submission Implementation

```elixir
def submit_to_provider(%Order{} = order) do
  order = Repo.preload(order, [:provider_connection, line_items: [product_variant: :product]])
  provider = Provider.for_type(order.provider_connection.provider_type)

  # Build provider-specific line items
  items = Enum.map(order.line_items, fn item ->
    provider.build_order_item(item.product_variant, item.quantity)
  end)

  # Submit via provider behaviour
  case provider.submit_order(order.provider_connection, %{
    line_items: items,
    shipping_address: order.shipping_address,
    external_id: order.order_number
  }) do
    {:ok, %{provider_order_id: provider_id}} ->
      order
      |> Order.changeset(%{provider_order_id: provider_id, status: "submitted"})
      |> Repo.update()

    {:error, reason} ->
      {:error, reason}
  end
end
```

### Key Insight

The `provider_variant_id` field serves a **dual purpose**:
1. **Sync**: We receive it from the provider and store it
2. **Order**: We send it back to the provider when fulfilling

This is why it's stored as a string - different providers use different formats (integers, UUIDs, compound UIDs), but we treat them all as opaque identifiers.

Sources:
- [Printify API Reference](https://developers.printify.com/)
- [Printful API Documentation](https://developers.printful.com/docs/)
- [Gelato API - Create Order](https://dashboard.gelato.com/docs/orders/v4/create/)
- [Prodigi API Documentation](https://www.prodigi.com/print-api/docs/reference/)

---

## Sync Strategy

1. Fetch all products from provider via API
2. For each product:
   - Find existing by `[provider_connection_id, provider_product_id]`
   - Upsert product with changeset
   - Delete removed images, insert new ones
   - Upsert variants (delete removed, update existing, insert new)
3. Update `provider_connection.last_synced_at`

Sync runs via Oban worker for async processing with retry on failure.

---

## Files to Create

### Dependencies
Add to `mix.exs`:
- `{:ex_money, "~> 5.0"}` - Currency handling
- `{:ex_money_sql, "~> 1.0"}` - Ecto types for Money

### Migrations
- `*_create_provider_connections.exs`
- `*_create_products.exs`
- `*_create_product_images.exs`
- `*_create_product_variants.exs`
- `*_create_orders.exs`
- `*_create_order_fulfillments.exs`
- `*_create_order_line_items.exs`
- `*_create_order_events.exs`
- `*_create_admin_notifications.exs`

### Schemas
- `lib/simpleshop_theme/products/provider_connection.ex`
- `lib/simpleshop_theme/products/product.ex`
- `lib/simpleshop_theme/products/product_image.ex`
- `lib/simpleshop_theme/products/product_variant.ex`
- `lib/simpleshop_theme/orders/order.ex`
- `lib/simpleshop_theme/orders/order_fulfillment.ex`
- `lib/simpleshop_theme/orders/order_line_item.ex`
- `lib/simpleshop_theme/orders/order_event.ex`
- `lib/simpleshop_theme/admin_notifications/notification.ex`

### Contexts
- `lib/simpleshop_theme/products.ex` - Product queries, sync logic
- `lib/simpleshop_theme/orders.ex` - Order creation, submission
- `lib/simpleshop_theme/admin_notifications.ex` - Admin notification management

### Providers
- `lib/simpleshop_theme/providers/provider.ex` - Behaviour definition
- `lib/simpleshop_theme/providers/printify.ex` - Printify implementation

### Workers
- `lib/simpleshop_theme/sync/product_sync_worker.ex` - Oban worker

### Webhooks
- `lib/simpleshop_theme_web/controllers/webhook_controller.ex`
- `lib/simpleshop_theme/webhooks/printify_handler.ex`

### Notifiers
- `lib/simpleshop_theme_web/notifiers/customer_notifier.ex` - Customer emails

### Support
- `lib/simpleshop_theme/vault.ex` - Credential encryption

---

## Files to Modify

- `lib/simpleshop_theme/printify/client.ex` → Move to `lib/simpleshop_theme/clients/printify.ex`
- `lib/simpleshop_theme/printify/mockup_generator.ex` → Move to `lib/simpleshop_theme/mockups/generator.ex`
- `lib/simpleshop_theme/theme/preview_data.ex` - Query real products when available
- `lib/simpleshop_theme_web/live/shop_live/*.ex` - Use Products context instead of PreviewData

---

## Implementation Phases

### Phase 1: Schema Foundation
1. Create Vault module for credential encryption
2. Create all migrations
3. Create all schema modules
4. Run migrations

### Phase 2: Products Context
1. Create Products context with CRUD
2. Implement sync/upsert logic
3. Create ProductSyncWorker (Oban)
4. Update Printify.Client with get_products endpoint

### Phase 3: Provider Abstraction
1. Create Provider behaviour
2. Implement Printify provider
3. Connect admin UI for provider setup
4. Test sync flow end-to-end

### Phase 4: Orders
1. Create Orders context
2. Implement order submission to provider
3. Add order status tracking

### Phase 5: Integration
1. Update PreviewData to use real products
2. Update shop LiveViews
3. Update cart to use real variant IDs

---

## Notifications Strategy

### Admin Notifications (Internal)
Stored in database, shown in admin dashboard:

```elixir
schema "admin_notifications" do
  field :type, :string        # "sync_error", "order_failed", "webhook_error"
  field :severity, :string    # "info", "warning", "error"
  field :title, :string
  field :message, :string
  field :metadata, :map
  field :read_at, :utc_datetime
  timestamps()
end
```

**Use cases:** Sync failures, order submission errors, provider API issues.

### Customer Notifications
Two mechanisms:
1. **Transactional emails** via `CustomerNotifier` (order confirmation, shipping updates)
2. **Order events** table for timeline display on order page

```elixir
# order_events - visible to customer on their order page
schema "order_events" do
  belongs_to :order
  field :type, :string      # "placed", "paid", "shipped", "delivered"
  field :message, :string   # Human-readable status
  field :metadata, :map     # {tracking_number, carrier, fulfillment_id}
  timestamps()
end
```

### Files to Create
- `lib/simpleshop_theme/admin_notifications.ex` - Admin notification context
- `lib/simpleshop_theme/admin_notifications/notification.ex` - Schema
- `lib/simpleshop_theme/orders/order_event.ex` - Customer-facing event schema
- `lib/simpleshop_theme_web/notifiers/customer_notifier.ex` - Emails

---

## Data Integrity: Checksum Approach

Use checksums to detect changes during sync (more robust than `updated_at` across providers):

```elixir
# On product schema
field :provider_checksum, :string

# Computing checksum
def compute_checksum(provider_data) do
  provider_data
  |> normalize_for_checksum()
  |> Jason.encode!(pretty: false)
  |> then(&:crypto.hash(:sha256, &1))
  |> Base.encode16(case: :lower)
end

defp normalize_for_checksum(data) do
  data
  |> Map.drop(["created_at", "updated_at"])  # Ignore volatile fields
  |> sort_keys_recursively()
end

# During sync
def needs_update?(existing_product, provider_data) do
  new_checksum = compute_checksum(provider_data)
  existing_product.provider_checksum != new_checksum
end
```

**Benefits:**
- Works regardless of provider timestamp support
- Catches any field change
- Avoids unnecessary database writes
- Stable across JSON key ordering variations

---

## Edge Cases (Follow-up Implementation Notes)

| Edge Case | Expected Behavior |
|-----------|-------------------|
| **Provider API down during sync** | Oban retries with exponential backoff (30s → 5min). After max_attempts (3), mark sync as `failed`. Create admin notification. |
| **Product deleted on provider** | Compare local products with provider list during sync. Mark missing products as `status: "archived"` (don't hard delete - preserves order history). |
| **Variant prices change mid-cart** | Cart stores `cached_price` at add-time. On checkout, re-validate current prices. Show warning to customer if price increased, allow proceed if decreased. |
| **`provider_variant_id` format changes** | Already stored as string. Provider behaviour's `normalize_variant/2` handles format. If API version changes, update provider module. |
| **Provider returns malformed data** | Validate in `normalize_product/1`. Log error, skip malformed product, continue batch. Don't fail entire sync. |
| **Rate limiting from provider** | Single sync worker (queue concurrency: 1). Add configurable delay between paginated requests. Respect Retry-After headers. |
| **Sync interrupted mid-batch** | Track sync progress in `provider_connection.sync_metadata`. On resume, continue from last successful page. |
| **Duplicate slugs across providers** | Generate slug with provider suffix on collision: `awesome-shirt-abc123` where `abc123` is short provider product ID. |
| **Webhook signature validation** | Each provider has different signing. Validate HMAC signature before processing. Reject invalid webhooks with 401. |
| **Order submission fails** | Keep order as `status: "pending"`. Retry via Oban worker. After max retries, mark as `status: "failed"`, notify admin. |

---

## Testing Strategy

### Test Setup

**Mocking External APIs (Mox pattern):**
```elixir
# test/support/mocks.ex
Mox.defmock(SimpleshopTheme.Clients.MockPrintify, for: SimpleshopTheme.Clients.PrintifyBehaviour)

# config/test.exs
config :simpleshop_theme, :printify_client, SimpleshopTheme.Clients.MockPrintify
```

**Oban testing:**
```elixir
use Oban.Testing, repo: SimpleshopTheme.Repo
# Jobs run synchronously in tests via perform_job/2
```

### Unit Tests

| Module | Test Coverage |
|--------|---------------|
| **Products.Product** | Changeset validation, slug generation, status transitions |
| **Products.ProductVariant** | Options validation, price/cost integrity |
| **Products.ProviderConnection** | Credential encryption/decryption, config validation |
| **Providers.Printify** | `normalize_product/1`, `normalize_variant/2`, `build_order_item/2` |
| **Orders.Order** | Status aggregation from fulfillments, total calculation |
| **Orders.OrderFulfillment** | Status transitions, tracking updates |
| **AdminNotifications** | Create, list_unread, mark_read |

### Integration Tests

| Flow | Test Scenarios |
|------|----------------|
| **Product Sync** | Successful sync, partial failures, pagination, checksum skip, archived products |
| **Order Creation** | Single provider, multi-provider split into fulfillments |
| **Order Submission** | Success, API failure with retry, partial fulfillment submission |
| **Webhook Handling** | Valid signature, invalid signature rejection, status updates |
| **Variant Selector** | Option extraction, availability filtering, variant matching |

### Example Test Cases

```elixir
# test/simpleshop_theme/products_test.exs
describe "sync_products/1" do
  test "syncs products from provider" do
    conn = provider_connection_fixture()

    expect(MockPrintify, :list_products, fn _shop_id ->
      {:ok, [printify_product_fixture()]}
    end)

    assert {:ok, %{synced: 1, failed: 0}} = Products.sync_products(conn)
    assert [product] = Products.list_products()
    assert product.title == "Test Product"
  end

  test "continues on single product failure" do
    expect(MockPrintify, :list_products, fn _ ->
      {:ok, [valid_product(), malformed_product()]}
    end)

    assert {:ok, %{synced: 1, failed: 1}} = Products.sync_products(conn)
  end

  test "skips unchanged products via checksum" do
    existing = product_fixture(provider_checksum: "abc123")

    expect(MockPrintify, :list_products, fn _ ->
      {:ok, [product_with_same_checksum()]}
    end)

    assert {:ok, %{synced: 0, skipped: 1}} = Products.sync_products(conn)
  end
end

# test/simpleshop_theme/orders_test.exs
describe "create_order_from_cart/1" do
  test "splits cart into fulfillments by provider" do
    printify_variant = variant_fixture(provider: :printify)
    gelato_variant = variant_fixture(provider: :gelato)

    cart = [
      %{variant_id: printify_variant.id, quantity: 1},
      %{variant_id: gelato_variant.id, quantity: 2}
    ]

    assert {:ok, order} = Orders.create_order_from_cart(cart, customer_params())
    assert length(order.order_fulfillments) == 2
  end
end

# test/simpleshop_theme/sync/product_sync_worker_test.exs
describe "perform/1" do
  test "retries on API failure" do
    expect(MockPrintify, :list_products, fn _ -> {:error, :timeout} end)

    assert {:error, :timeout} = perform_job(ProductSyncWorker, %{conn_id: conn.id})
    # Oban will retry automatically
  end

  test "creates admin notification on final failure" do
    # After max_attempts...
    assert [notification] = AdminNotifications.list_unread()
    assert notification.type == "sync_error"
  end
end
```

### Test Fixtures

```elixir
# test/support/fixtures/products_fixtures.ex
def provider_connection_fixture(attrs \\ %{}) do
  {:ok, conn} = Products.create_provider_connection(%{
    provider_type: "printify",
    name: "Test Connection",
    api_key: "test_key",
    config: %{"shop_id" => "123"}
  } |> Map.merge(attrs))
  conn
end

def product_fixture(attrs \\ %{}) do
  conn = attrs[:provider_connection] || provider_connection_fixture()
  {:ok, product} = Products.create_product(%{
    provider_connection_id: conn.id,
    provider_product_id: "ext_#{System.unique_integer()}",
    title: "Test Product",
    slug: "test-product-#{System.unique_integer()}",
    status: "active"
  } |> Map.merge(attrs))
  product
end

def printify_product_fixture do
  %{
    "id" => "12345",
    "title" => "Test Product",
    "description" => "A test product",
    "options" => [%{"name" => "Size", "values" => [%{"id" => 1, "title" => "M"}]}],
    "variants" => [%{"id" => 100, "options" => [1], "price" => 2500}],
    "images" => [%{"src" => "https://example.com/img.jpg", "position" => 0}]
  }
end
```

### Coverage Goals

| Area | Target |
|------|--------|
| Schema modules | 100% (validation, associations) |
| Context functions | 90%+ (all public functions) |
| Provider implementations | 90%+ (normalize, build functions) |
| Oban workers | 80%+ (happy path, error handling) |
| LiveView interactions | 70%+ (critical user flows) |

---

---

## Task: Admin Provider Setup UI

> **Status:** Next up
> **Estimate:** ~2 hours
> **Prerequisite:** Phase 1 complete (schemas, context, Printify provider)

### Goal

Add an admin UI at `/admin/providers` for managing POD provider connections. This enables shop owners to connect their Printify account and trigger product syncs without using IEx.

### User Stories

1. **Connect provider:** Enter Printify API key, test connection, save
2. **View status:** See connected providers, last sync time, product count
3. **Trigger sync:** Manually sync products from provider
4. **Disconnect:** Remove a provider connection

### Routes

```elixir
# In router.ex, within :require_authenticated_user live_session
live "/admin/providers", ProviderLive.Index, :index
live "/admin/providers/new", ProviderLive.Index, :new
live "/admin/providers/:id/edit", ProviderLive.Index, :edit
```

### Files to Create/Modify

| File | Purpose |
|------|---------|
| `lib/simpleshop_theme_web/live/provider_live/index.ex` | LiveView for provider list + modal forms |
| `lib/simpleshop_theme_web/live/provider_live/index.html.heex` | Template |
| `lib/simpleshop_theme_web/live/provider_live/form_component.ex` | Form component for new/edit |
| `lib/simpleshop_theme/providers/printify.ex` | Add `register_webhooks/1`, `unregister_webhooks/1` |
| `lib/simpleshop_theme/workers/product_sync_worker.ex` | Stub for "Sync Now" (full impl in next task) |
| `test/simpleshop_theme_web/live/provider_live_test.exs` | LiveView tests |

### UI Design

Single-page admin with modal for add/edit (follows Phoenix generator pattern):

```
┌─────────────────────────────────────────────────────────────┐
│  Admin › Provider Connections                    [+ Add]    │
├─────────────────────────────────────────────────────────────┤
│                                                             │
│  ┌─────────────────────────────────────────────────────┐   │
│  │  🟢 Printify                              [Edit] [×] │   │
│  │  "My Printify Shop"                                  │   │
│  │  Shop: Acme Store • 24 products                      │   │
│  │  Last synced: 5 minutes ago                          │   │
│  │                                        [Sync Now]    │   │
│  └─────────────────────────────────────────────────────┘   │
│                                                             │
│  ┌─────────────────────────────────────────────────────┐   │
│  │  ⚪ Gelato                                [Edit] [×] │   │
│  │  "Gelato Account"                                    │   │
│  │  Not connected (invalid API key)                     │   │
│  │                                        [Sync Now]    │   │
│  └─────────────────────────────────────────────────────┘   │
│                                                             │
└─────────────────────────────────────────────────────────────┘
```

**Add/Edit Modal:**

```
┌─────────────────────────────────────────────────────────────┐
│  Connect Printify                                    [×]    │
├─────────────────────────────────────────────────────────────┤
│                                                             │
│  Name                                                       │
│  ┌─────────────────────────────────────────────────────┐   │
│  │ My Printify Shop                                    │   │
│  └─────────────────────────────────────────────────────┘   │
│                                                             │
│  API Key                                                    │
│  ┌─────────────────────────────────────────────────────┐   │
│  │ ••••••••••••••••••••                                │   │
│  └─────────────────────────────────────────────────────┘   │
│  Get your API key from Printify Settings → Connections      │
│                                                             │
│  ┌──────────────────┐                                       │
│  │  Test Connection │  ✓ Connected to "Acme Store"         │
│  └──────────────────┘                                       │
│                                                             │
│  □ Enable automatic sync                                    │
│                                                             │
│                              [Cancel]  [Save Connection]    │
└─────────────────────────────────────────────────────────────┘
```

### LiveView Implementation

**Index LiveView (`provider_live/index.ex`):**

```elixir
defmodule SimpleshopThemeWeb.ProviderLive.Index do
  use SimpleshopThemeWeb, :live_view

  alias SimpleshopTheme.Products
  alias SimpleshopTheme.Products.ProviderConnection

  @impl true
  def mount(_params, _session, socket) do
    connections = Products.list_provider_connections()
    {:ok, stream(socket, :connections, connections)}
  end

  @impl true
  def handle_params(params, _url, socket) do
    {:noreply, apply_action(socket, socket.assigns.live_action, params)}
  end

  defp apply_action(socket, :edit, %{"id" => id}) do
    socket
    |> assign(:page_title, "Edit Provider")
    |> assign(:connection, Products.get_provider_connection!(id))
  end

  defp apply_action(socket, :new, _params) do
    socket
    |> assign(:page_title, "Add Provider")
    |> assign(:connection, %ProviderConnection{})
  end

  defp apply_action(socket, :index, _params) do
    socket
    |> assign(:page_title, "Provider Connections")
    |> assign(:connection, nil)
  end

  @impl true
  def handle_info({SimpleshopThemeWeb.ProviderLive.FormComponent, {:saved, connection}}, socket) do
    {:noreply, stream_insert(socket, :connections, connection)}
  end

  @impl true
  def handle_event("delete", %{"id" => id}, socket) do
    connection = Products.get_provider_connection!(id)
    {:ok, _} = Products.delete_provider_connection(connection)
    {:noreply, stream_delete(socket, :connections, connection)}
  end

  @impl true
  def handle_event("sync", %{"id" => id}, socket) do
    connection = Products.get_provider_connection!(id)
    # Enqueue sync job (Oban worker)
    {:ok, _job} = Products.enqueue_sync(connection)

    {:noreply,
     socket
     |> put_flash(:info, "Sync started for #{connection.name}")
     |> stream_insert(:connections, %{connection | sync_status: "syncing"})}
  end
end
```

**Form Component (`provider_live/form_component.ex`):**

Key features:
- Provider type dropdown (Printify only initially, extensible)
- API key field (password type, shows masked on edit)
- "Test Connection" button with async feedback
- Validation before save
- Auto-registers webhooks on successful save

```elixir
def handle_event("test_connection", _params, socket) do
  form_data = socket.assigns.form.source.changes
  api_key = form_data[:api_key] || socket.assigns.connection.api_key

  case test_provider_connection(socket.assigns.provider_type, api_key) do
    {:ok, %{shop_name: name}} ->
      {:noreply, assign(socket, test_result: {:ok, name})}

    {:error, reason} ->
      {:noreply, assign(socket, test_result: {:error, reason})}
  end
end

defp test_provider_connection("printify", api_key) do
  # Build temporary connection struct for testing
  conn = %ProviderConnection{provider_type: "printify", api_key: api_key}
  SimpleshopTheme.Providers.Printify.test_connection(conn)
end
```

### Events

| Event | Handler | Action |
|-------|---------|--------|
| `"validate"` | FormComponent | Live validation of form fields |
| `"test_connection"` | FormComponent | Call provider's `test_connection/1`, show result |
| `"save"` | FormComponent | Create/update connection, register webhooks, notify parent |
| `"delete"` | Index | Unregister webhooks, delete connection |
| `"sync"` | Index | Enqueue `ProductSyncWorker` job |

### Webhook Registration Flow

When a provider connection is saved, automatically register webhooks with the provider so real-time sync works immediately.

**On Save (FormComponent):**

```elixir
def handle_event("save", %{"provider" => params}, socket) do
  save_result = case socket.assigns.connection.id do
    nil -> Products.create_provider_connection(params)
    _id -> Products.update_provider_connection(socket.assigns.connection, params)
  end

  case save_result do
    {:ok, connection} ->
      # Register webhooks after successful save
      case register_webhooks(connection) do
        {:ok, _} ->
          Products.update_provider_connection(connection, %{
            config: Map.put(connection.config, "webhooks_registered", true)
          })

        {:error, reason} ->
          # Log but don't fail - webhooks can be registered later
          Logger.warning("Failed to register webhooks: #{inspect(reason)}")
      end

      notify_parent({:saved, connection})
      {:noreply,
       socket
       |> put_flash(:info, "Provider connected successfully")
       |> push_patch(to: socket.assigns.patch)}

    {:error, changeset} ->
      {:noreply, assign(socket, form: to_form(changeset))}
  end
end

defp register_webhooks(%{provider_type: "printify"} = conn) do
  SimpleshopTheme.Providers.Printify.register_webhooks(conn)
end
```

**On Delete (Index):**

```elixir
def handle_event("delete", %{"id" => id}, socket) do
  connection = Products.get_provider_connection!(id)

  # Unregister webhooks before deleting
  unregister_webhooks(connection)

  {:ok, _} = Products.delete_provider_connection(connection)
  {:noreply, stream_delete(socket, :connections, connection)}
end

defp unregister_webhooks(%{provider_type: "printify"} = conn) do
  SimpleshopTheme.Providers.Printify.unregister_webhooks(conn)
end
```

**Provider Webhook Functions (add to `Providers.Printify`):**

```elixir
@webhook_topics ~w(product:publish:started product:deleted shop:disconnected)

def register_webhooks(conn) do
  webhook_url = SimpleshopThemeWeb.Endpoint.url() <> "/webhooks/printify"
  shop_id = get_shop_id(conn)

  results = Enum.map(@webhook_topics, fn topic ->
    Client.post(conn, "/shops/#{shop_id}/webhooks.json", %{
      topic: topic,
      url: webhook_url
    })
  end)

  if Enum.all?(results, &match?({:ok, _}, &1)) do
    {:ok, :registered}
  else
    {:error, :partial_registration}
  end
end

def unregister_webhooks(conn) do
  shop_id = get_shop_id(conn)

  # List existing webhooks and delete ours
  case Client.get(conn, "/shops/#{shop_id}/webhooks.json") do
    {:ok, %{"webhooks" => webhooks}} ->
      our_url = SimpleshopThemeWeb.Endpoint.url() <> "/webhooks/printify"

      webhooks
      |> Enum.filter(&(&1["url"] == our_url))
      |> Enum.each(&Client.delete(conn, "/shops/#{shop_id}/webhooks/#{&1["id"]}.json"))

      {:ok, :unregistered}

    error ->
      error
  end
end
```

### UI: Webhook Status Indicator

Show webhook status on the connection card:

```
┌─────────────────────────────────────────────────────────┐
│  🟢 Printify                              [Edit] [×]    │
│  "My Printify Shop"                                     │
│  Shop: Acme Store • 24 products                         │
│  Last synced: 5 minutes ago                             │
│  ✓ Real-time updates enabled              [Sync Now]    │  ← webhook status
└─────────────────────────────────────────────────────────┘
```

Or if webhooks failed to register:

```
│  ⚠ Real-time updates unavailable (click Sync manually)  │
```

Template snippet:
```heex
<div class="text-sm text-gray-500">
  <%= if @connection.config["webhooks_registered"] do %>
    <.icon name="hero-check-circle" class="w-4 h-4 text-green-500" />
    Real-time updates enabled
  <% else %>
    <.icon name="hero-exclamation-triangle" class="w-4 h-4 text-amber-500" />
    Real-time updates unavailable
  <% end %>
</div>
```

### Context Additions

Add to `lib/simpleshop_theme/products.ex`:

```elixir
@doc """
Enqueues a product sync job for the given provider connection.
Returns {:ok, job} or {:error, changeset}.
"""
def enqueue_sync(%ProviderConnection{} = conn) do
  %{connection_id: conn.id}
  |> SimpleshopTheme.Workers.ProductSyncWorker.new()
  |> Oban.insert()
end

@doc """
Gets product count for a provider connection.
"""
def count_products_for_connection(connection_id) do
  from(p in Product, where: p.provider_connection_id == ^connection_id, select: count())
  |> Repo.one()
end
```

### Acceptance Criteria

1. **Navigation:** `/admin` shows link to "Providers" in admin nav
2. **List view:** Shows all provider connections with status indicators
3. **Add flow:** Modal form with provider type, name, API key fields
4. **Test connection:** Button validates API key, shows shop name or error
5. **Save:** Creates encrypted connection, registers webhooks, closes modal, updates list
6. **Webhook status:** Card shows "Real-time updates enabled" or warning if registration failed
7. **Edit:** Pre-fills form (API key masked), allows updates, re-registers webhooks if key changed
8. **Delete:** Unregisters webhooks, confirmation dialog, removes connection
9. **Sync:** Button enqueues Oban job, shows "syncing" status
10. **Empty state:** Helpful message when no providers connected
11. **Auth:** Only accessible to authenticated admin users

### Testing

```elixir
# test/simpleshop_theme_web/live/provider_live_test.exs
describe "Index" do
  setup :register_and_log_in_user

  test "lists all provider connections", %{conn: conn} do
    connection = provider_connection_fixture()
    {:ok, _lv, html} = live(conn, ~p"/admin/providers")
    assert html =~ connection.name
  end

  test "saves new provider connection", %{conn: conn} do
    {:ok, lv, _html} = live(conn, ~p"/admin/providers/new")

    # Mock test_connection response
    expect_test_connection_success()

    lv
    |> form("#provider-form", provider: %{name: "Test", api_key: "key123"})
    |> render_submit()

    assert_patch(lv, ~p"/admin/providers")
    assert render(lv) =~ "Test"
  end

  test "deletes provider connection", %{conn: conn} do
    connection = provider_connection_fixture()
    {:ok, lv, _html} = live(conn, ~p"/admin/providers")

    lv |> element("#connection-#{connection.id} button", "Delete") |> render_click()

    refute render(lv) =~ connection.name
  end
end
```

### Dependencies

- **ProductSyncWorker:** Must exist (stub OK, full implementation separate task)
- **Providers.Printify.test_connection/1:** Already implemented
- **Providers.Printify.register_webhooks/1:** Implement as part of this task
- **Providers.Printify.unregister_webhooks/1:** Implement as part of this task

### Out of Scope (Future Tasks)

- Product list/management UI (`/admin/products`)
- Real-time sync progress updates (PubSub)
- OAuth flow for providers that support it
- Multiple connections per provider type

---

## Task: Product Sync Strategy

> **Status:** Planned
> **Estimate:** ~2.5 hours total
> **Prerequisite:** Admin Provider Setup UI

### Goal

Implement a robust product sync strategy with three mechanisms:
1. **Manual sync** - Admin clicks "Sync Now" (initial setup, recovery)
2. **Webhook sync** - Printify pushes updates in real-time (primary)
3. **Scheduled sync** - Daily fallback to catch missed webhooks (optional)

### Printify Webhook Events

| Event | Trigger | Action |
|-------|---------|--------|
| `product:publish:started` | Product published to shop | Fetch & upsert product |
| `product:deleted` | Product removed from shop | Archive product locally |
| `shop:disconnected` | API access revoked | Mark connection as disconnected |

### Files to Create

| File | Purpose |
|------|---------|
| `lib/simpleshop_theme/workers/product_sync_worker.ex` | Oban worker for full/single product sync |
| `lib/simpleshop_theme_web/controllers/webhook_controller.ex` | Receives webhooks from providers |
| `lib/simpleshop_theme/webhooks/printify_handler.ex` | Printify-specific webhook processing |
| `test/simpleshop_theme/workers/product_sync_worker_test.exs` | Worker tests |
| `test/simpleshop_theme_web/controllers/webhook_controller_test.exs` | Webhook endpoint tests |

### Part 1: ProductSyncWorker (~1hr)

Oban worker that syncs products from a provider connection.

```elixir
defmodule SimpleshopTheme.Workers.ProductSyncWorker do
  use Oban.Worker,
    queue: :sync,
    max_attempts: 3,
    unique: [period: 60, fields: [:args, :queue]]

  alias SimpleshopTheme.Products
  alias SimpleshopTheme.Providers

  @impl Oban.Worker
  def perform(%Oban.Job{args: %{"connection_id" => conn_id} = args}) do
    conn = Products.get_provider_connection!(conn_id)
    provider = Providers.for_type(conn.provider_type)

    Products.update_sync_status(conn, "syncing", nil)

    result = case args do
      %{"product_id" => product_id} ->
        # Single product sync (from webhook)
        sync_single_product(conn, provider, product_id)

      _ ->
        # Full sync (manual or scheduled)
        sync_all_products(conn, provider)
    end

    case result do
      {:ok, stats} ->
        Products.update_sync_status(conn, "completed", DateTime.utc_now())
        {:ok, stats}

      {:error, reason} ->
        Products.update_sync_status(conn, "failed", nil)
        {:error, reason}
    end
  end

  defp sync_all_products(conn, provider) do
    case provider.fetch_products(conn) do
      {:ok, products} ->
        stats = Enum.reduce(products, %{synced: 0, failed: 0}, fn product, acc ->
          case Products.upsert_product(conn, product) do
            {:ok, _} -> %{acc | synced: acc.synced + 1}
            {:error, _} -> %{acc | failed: acc.failed + 1}
          end
        end)
        {:ok, stats}

      {:error, reason} ->
        {:error, reason}
    end
  end

  defp sync_single_product(conn, provider, product_id) do
    case provider.fetch_product(conn, product_id) do
      {:ok, product} ->
        Products.upsert_product(conn, product)

      {:error, :not_found} ->
        # Product deleted on provider
        Products.archive_product_by_provider(conn.id, product_id)

      {:error, reason} ->
        {:error, reason}
    end
  end
end
```

**Job types:**
- Full sync: `%{connection_id: conn.id}`
- Single product: `%{connection_id: conn.id, product_id: "ext_123"}`
- Archive: `%{connection_id: conn.id, product_id: "ext_123", action: "archive"}`

### Part 2: Webhook Endpoint (~1.5hr)

**Route:**
```elixir
# In router.ex (outside auth scopes - public endpoint)
post "/webhooks/printify", WebhookController, :printify
```

**Controller:**
```elixir
defmodule SimpleshopThemeWeb.WebhookController do
  use SimpleshopThemeWeb, :controller

  alias SimpleshopTheme.Webhooks.PrintifyHandler

  def printify(conn, params) do
    with :ok <- verify_printify_signature(conn),
         :ok <- PrintifyHandler.handle(params) do
      json(conn, %{status: "ok"})
    else
      {:error, :invalid_signature} ->
        conn |> put_status(401) |> json(%{error: "Invalid signature"})

      {:error, reason} ->
        conn |> put_status(422) |> json(%{error: reason})
    end
  end

  defp verify_printify_signature(conn) do
    # Printify signs webhooks with HMAC-SHA256
    # Header: X-Printify-Signature
    signature = get_req_header(conn, "x-printify-signature") |> List.first()
    body = conn.assigns[:raw_body]
    secret = Application.get_env(:simpleshop_theme, :printify_webhook_secret)

    expected = :crypto.mac(:hmac, :sha256, secret, body) |> Base.encode16(case: :lower)

    if Plug.Crypto.secure_compare(signature || "", expected) do
      :ok
    else
      {:error, :invalid_signature}
    end
  end
end
```

**Handler:**
```elixir
defmodule SimpleshopTheme.Webhooks.PrintifyHandler do
  alias SimpleshopTheme.Products
  alias SimpleshopTheme.Workers.ProductSyncWorker

  def handle(%{"type" => "product:publish:started", "resource" => resource}) do
    %{"shop_id" => shop_id, "id" => product_id} = resource

    with {:ok, conn} <- find_connection_by_shop(shop_id) do
      %{connection_id: conn.id, product_id: to_string(product_id)}
      |> ProductSyncWorker.new()
      |> Oban.insert()
    end
  end

  def handle(%{"type" => "product:deleted", "resource" => resource}) do
    %{"shop_id" => shop_id, "id" => product_id} = resource

    with {:ok, conn} <- find_connection_by_shop(shop_id) do
      Products.archive_product_by_provider(conn.id, to_string(product_id))
    end
  end

  def handle(%{"type" => "shop:disconnected", "resource" => %{"shop_id" => shop_id}}) do
    with {:ok, conn} <- find_connection_by_shop(shop_id) do
      Products.update_provider_connection(conn, %{enabled: false, sync_status: "disconnected"})
    end
  end

  def handle(%{"type" => type}) do
    # Log unknown webhook types but don't fail
    Logger.info("Unhandled Printify webhook: #{type}")
    :ok
  end

  defp find_connection_by_shop(shop_id) do
    case Products.get_provider_connection_by_shop_id("printify", shop_id) do
      nil -> {:error, :connection_not_found}
      conn -> {:ok, conn}
    end
  end
end
```

### Part 3: Scheduled Sync (Optional)

Add to Oban config for daily fallback:
```elixir
# In config/config.exs
config :simpleshop_theme, Oban,
  plugins: [
    {Oban.Plugins.Cron, crontab: [
      {"0 3 * * *", SimpleshopTheme.Workers.ScheduledSyncWorker}  # 3 AM daily
    ]}
  ]
```

```elixir
defmodule SimpleshopTheme.Workers.ScheduledSyncWorker do
  use Oban.Worker, queue: :sync

  def perform(_job) do
    Products.list_provider_connections(enabled: true)
    |> Enum.each(fn conn ->
      %{connection_id: conn.id}
      |> ProductSyncWorker.new(schedule_in: Enum.random(0..300))  # Stagger over 5 min
      |> Oban.insert()
    end)

    :ok
  end
end
```

### Context Additions

Add to `lib/simpleshop_theme/products.ex`:

```elixir
def archive_product_by_provider(connection_id, provider_product_id) do
  case get_product_by_provider(connection_id, provider_product_id) do
    nil -> {:ok, :not_found}
    product -> update_product(product, %{status: "archived", visible: false})
  end
end

def get_provider_connection_by_shop_id(provider_type, shop_id) do
  from(c in ProviderConnection,
    where: c.provider_type == ^provider_type,
    where: fragment("json_extract(config, '$.shop_id') = ?", ^shop_id)
  )
  |> Repo.one()
end
```

### Webhook Registration

Webhook registration with Printify is handled by the Admin Provider Setup UI task:
- **On save:** `Providers.Printify.register_webhooks/1` is called
- **On delete:** `Providers.Printify.unregister_webhooks/1` cleans up

See the "Webhook Registration Flow" section in the Admin Provider Setup UI task for implementation details.

**Note:** Webhooks require a public URL. For local dev, use ngrok or similar:
```bash
ngrok http 4000
# Then set WEBHOOK_URL=https://abc123.ngrok.io in .env
```

### Acceptance Criteria

1. **Manual sync:** "Sync Now" button enqueues ProductSyncWorker, products appear
2. **Webhook received:** POST to `/webhooks/printify` with valid signature succeeds
3. **Invalid signature:** Returns 401, no job enqueued
4. **Product published:** Webhook triggers single-product sync
5. **Product deleted:** Webhook archives product locally
6. **Shop disconnected:** Connection marked as disabled
7. **Scheduled sync:** (If implemented) Runs daily, syncs all enabled connections

### Testing

```elixir
describe "WebhookController.printify/2" do
  test "rejects invalid signature" do
    conn = post(build_conn(), ~p"/webhooks/printify", %{type: "product:deleted"})
    assert json_response(conn, 401)["error"] == "Invalid signature"
  end

  test "handles product:publish:started" do
    conn = provider_connection_fixture(config: %{"shop_id" => "12345"})

    payload = %{"type" => "product:publish:started", "resource" => %{"shop_id" => "12345", "id" => "prod_1"}}

    conn = post(signed_conn(payload), ~p"/webhooks/printify", payload)
    assert json_response(conn, 200)

    assert_enqueued(worker: ProductSyncWorker, args: %{connection_id: conn.id, product_id: "prod_1"})
  end
end
```

---

## Verification (Manual)
   - Create Printify connection with API key
   - `Products.test_provider_connection(conn)` returns shop info

2. **Product Sync**
   - Run `ProductSyncWorker.enqueue(conn.id)`
   - Products appear in database with images and variants
   - Re-sync updates existing, doesn't duplicate

3. **Order Submission**
   - Create order from cart
   - `Orders.submit_to_provider(order)` returns provider_order_id
   - Order status updates from provider

4. **Shop Pages**
   - `/collections/all` shows real products
   - `/products/:slug` shows product details
   - Add to cart works with real variant IDs