# Delivery Date & Time — Shopify App

Scheduling app for Shipping / Local Delivery / Store Pickup with date-time slots,
capacity intelligence, and all-plan checkout enforcement. See `PRODUCT_STRATEGY.md`
(why) and `IMPLEMENTATION_PLAN.md` (how). Build in the phases defined there, in order.

## Stack
Remix + Polaris + App Bridge · Prisma/Postgres · Redis/BullMQ · GraphQL Admin API ·
Theme App Extension (Preact) · Checkout UI Extensions (React) · Shopify Functions (Rust) ·
POS UI Extension · TypeScript strict · Vitest + Playwright.

## Non-negotiables
- Enforcement is server-side (Cart/Checkout **Validation Function**), never client-only.
  The storefront widget collects; the Function enforces. This is what makes the app work
  on non-Plus plans, which is the core competitive moat.
- All date math is timezone/DST-safe (Luxon) and unit-tested BEFORE any UI is wired.
- One Scheduling Service + one capacity pool feeds every surface (web / checkout / POS).
  Behavior must never diverge between channels.
- Multi-tenant: every DB query scoped by `shopDomain`.
- Request the MINIMUM OAuth scopes needed. Secrets live in `.env`, never committed.
- Each phase ships tested, working software; do not skip a phase's acceptance criteria.
- Slot-holds (Redis, TTL) prevent last-slot double-booking — this has a dedicated
  concurrency test that must pass.

## Commands
- `shopify app dev`            — local dev against a dev store
- `npm test`                   — Vitest unit tests
- `npm run test:e2e`           — Playwright E2E
- `npx prisma migrate dev`     — DB migrations
- `shopify app deploy`         — deploy extensions / functions

## Conventions
- Conventional commits; one feature branch per phase; small PRs per task.
- Polaris components only in the admin UI (Built-for-Shopify requirement).
- Pure functions in `app/services/*.server.ts` scheduling core — inject data, do no I/O
  inside the math so it stays unit-testable.
- No inline secrets or API keys anywhere in source.

## Current status
Greenfield. Start at Phase 0 (Scaffold & CI) in `IMPLEMENTATION_PLAN.md`.