Add Importing // Mapping Overview

Importing-%2F%2F-Mapping-Overview.md

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+# Battl Builder – Import & Mapping Flow Overview
+
+This document explains the entire data ingestion, normalization, and builder-level mapping process used in Battl Builder — from raw AvantLink feed → normalized Battl Builder product → categorized builder slot.
+
+---
+
+## 1. Big Picture Architecture
+
+Battl Builder’s data flow breaks into three layers:
+
+1. **Import Layer**  
+   _“What did the merchant send us?”_
+
+2. **Domain Layer**  
+   _“What is this part in Battl Builder language?”_
+
+3. **Builder Layer**  
+   _“Where does this part appear in the UI, and what slot does it fill?”_
+
+This doc walks through each step in plain English.
+
+---
+
+## 2. Import Layer (AvantLink → Battl Builder database)
+
+### 2.1 Merchants
+
+Table: `merchants`
+
+Each row stores:
+
+- Merchant name (“Primary Arms”, “Brownells”, etc.)
+- AvantLink MID  
+- Feed URLs  
+- Active flags  
+- Timestamps  
+
+**Purpose:**  
+Tell the importer *which* feeds exist and how to read them.
+
+---
+
+### 2.2 AvantLink Product & Offer Feeds
+
+Every merchant provides two key feeds:
+
+#### Product Feed
+- brand name  
+- product name  
+- description  
+- merchant’s category  
+- MPN, UPC, SKU  
+- main image  
+- etc.
+
+#### Offer Feed
+- price  
+- original MSRP  
+- availability  
+- buy URL  
+- merchant id  
+- AvantLink product id  
+- timestamps  
+
+The importer loops over these feeds continuously.
+
+---
+
+### 2.3 Normalizing Merchant Categories (merchant_category_mappings)
+
+Table: `merchant_category_mappings`
+
+Each row answers this question:
+
+> “When Merchant X says category string Y, what does that mean in our taxonomy?”
+
+Columns include:
+
+- `merchant_id`
+- `raw_category` (merchant’s text)
+- `mapped_part_role`  
+- `mapped_configuration`
+- timestamps
+
+This is the **first** normalization hop:
+
+**Merchant category → internal part_role**
+
+---
+
+### 2.4 Brands
+
+Table: `brands`
+
+Import logic:
+
+1. Try to find a case-insensitive match.
+2. If found: reuse it.
+3. If not found: create a new brand row.
+
+---
+
+### 2.5 Products
+
+Table: `products`
+
+Represents Battl Builder’s canonical catalog — not merchant-specific.
+
+Columns include:
+
+- `brand_id`
+- `name`
+- `part_role`
+- `platform`
+- `slug`
+- `mpn`, `upc`
+- descriptions  
+- main image  
+- `raw_category_key`
+- timestamps  
+
+**Import behavior:**
+
+1. Sync brand  
+2. Normalize category → part_role  
+3. Determine platform  
+4. Upsert product (insert or update)
+
+---
+
+### 2.6 Product Offers
+
+Table: `product_offers`
+
+Represents merchant-specific availability and pricing.
+
+Columns:
+
+- `product_id`
+- `merchant_id`
+- `price`, `original_price`
+- `currency`
+- `in_stock`
+- `buy_url`
+- timestamps  
+
+---
+
+## 3. Domain Layer (Mapping Into Builder Categories)
+
+### 3.1 Part Categories
+
+Table: `part_categories`
+
+Represents categories used in the builder UI such as:
+
+- lower  
+- upper  
+- barrel  
+- optic  
+- trigger  
+
+These map directly to the builder’s UI slots.
+
+---
+
+### 3.2 Part Role Mappings
+
+Table: `part_role_mappings`
+
+Maps from:
+
+> **platform + part_role → builder category**
+
+Example:
+
+```
+AR-15 + LOWER_RECEIVER_STRIPPED → lower
+AR-15 + OPTIC_LPVO → optic
+```
+
+This is the glue between raw import data and builder UI categories.
+
+---
+
+## 4. Builder Layer (Frontend Consumption)
+
+### How `/builder` loads parts
+
+Frontend calls:
+
+```
+GET /api/gunbuilder/products?platform=AR-15&partRoles=optic
+```
+
+Backend:
+
+1. Query products  
+2. Load offers  
+3. Map to DTOs  
+4. Return JSON  
+5. Frontend groups by category via part_role_mappings  
+
+---
+
+## 5. Relationship Between Mapping Systems
+
+| Layer | Table | Purpose |
+|-------|--------|----------|
+| Import | `merchant_category_mappings` | Convert merchant category → part_role |
+| Builder | `part_role_mappings` | Convert part_role → builder category slot |
+
+Flow:
+
+```
+Merchant raw category
+   ↓
+merchant_category_mappings
+   ↓
+products.part_role
+   ↓
+part_role_mappings
+   ↓
+part_categories.slug
+   ↓
+Builder slot (frontend)
+```
+
+---
+
+## 6. `/builds` Page
+
+Currently placeholder-only. Later it will store real builds composed from imported & mapped products.
+
+---
+
+## 7. Summary
+
+AvantLink feeds → merchant category mapping → products + offers → part_role_mappings → builder UI → user builds.