RFC 003: WMS Technical Specification

1. Domain Database Models

The Warehouse Management System (WMS) operates high-frequency inventory tracking using class-based SQLAlchemy structures linked to PostgreSQL:

class StockEntry(BaseDocType):
    """Core inventory transaction record."""

    posting_date: date
    purpose: str = Field(description="Receipt, Transfer, Issue")
    from_warehouse: str | None = Field(default=None, description="Source Warehouse ID")
    to_warehouse: str | None = Field(default=None, description="Destination Warehouse ID")
    company: str
    items: list["StockEntryItem"] = Field(default=[], description="Nested child items list")

    class Meta:
        table_name = "stock_entry"
        indexes = ["posting_date", "purpose"]

class Bin(BaseDocType):
    """Real-time inventory balance projection per Item and Warehouse."""

    item_code: str = Field(max_length=50)
    warehouse: str = Field(max_length=100)
    actual_qty: Decimal = Field(default=Decimal("0.000"))
    reserved_qty: Decimal = Field(default=Decimal("0.000"))
    ordered_qty: Decimal = Field(default=Decimal("0.000"))
    projected_qty: Decimal = Field(default=Decimal("0.000"))

    class Meta:
        table_name = "bin"
        unique_together = [("item_code", "warehouse")]
        indexes = ["item_code", "warehouse"]

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2. Automated Replenishment & Safety Stock Formulas

To maintain optimal branch stock, the Replenishment Engine executes an asynchronous cron worker evaluating projected stock balances:

2.1 Projected Stock Formula

$$\text{ProjectedQty} = \text{ActualQty} + \text{OrderedQty} - \text{ReservedQty}$$

2.2 Reorder Trigger & Quantity Calculation

For every active item in a Retail Outlet:

• If $\text{ProjectedQty} < \text{SafetyStockThreshold}$: $$\text{ReorderQuantity} = \text{MaximumAuthorizedCapacity} - \text{ProjectedQty}$$
• The WMS automatically raises a MaterialRequest DTO containing ReorderQuantity and queues it for HQ DC distribution.

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3. Frontend Micro-Frontend (MFE) Delivery

The WMS user interface is designed as an independent React/Tamagui sub-package located under libs/wms/frontend/.

graph TD
    Host[Host Gateway desk-shell] -->|Federation Load| Remote[http://wms-service:8080/mfe/remoteEntry.js]
    Remote -->|Imports Components| View[WMS Inventory Pages]

3.1 Vite Module Federation Configuration

The libs/wms/frontend/vite.config.ts declares the module as a federated remote:

import { defineConfig } from "vite";
import federation from "@originjs/vite-plugin-federation";

export default defineConfig({
  plugins: [
    federation({
      name: "wms",
      filename: "remoteEntry.js",
      exposes: {
        "./InventoryPanel": "./src/components/InventoryPanel.tsx",
        "./SupplierPortal": "./src/pages/SupplierPortal.tsx",
      },
      shared: ["react", "react-dom", "tamagui"],
    }),
  ],
});

At runtime in Enterprise Mode, the Host Gateway Desk Shell queries the dynamic schema and imports these modules asynchronously via remoteEntry.js.