# Returns and Refund Requests

## Objective

Let customers start a return from their order and follow it through to a refund.

A self-service return flow attached to each order, with item selection, a reason, and a tracked status through to resolution.

## Before You Begin

This feature is being added to an application that already exists and already
works. Do not scaffold a new project, and do not assume a blank slate.

Inspect the codebase first and establish:

- The existing application structure and where code of this kind already lives.
- The framework and version in use.
- The existing design system — colours, spacing, typography, and component conventions.
- Existing UI components you can reuse instead of writing new ones.
- The existing database structure, if this feature needs to persist anything.
- The existing authentication and authorization system, if this feature is user-scoped.
- Dependencies already installed, so you don't add a library that duplicates one.
- The existing test setup and conventions.

Only start writing code once you understand the above. If the application
already implements part of this feature, extend it rather than replacing it.

## Implementation Instructions

1. Start the flow from the order itself, not from a generic support form. The customer should pick the items and quantities from the order they are already looking at.
2. Ask for a reason from a short fixed list plus an optional note, because the fixed list is what makes the data useful and the note is what makes the customer feel heard.
3. Give the request its own visible status the customer can check without emailing anyone: requested, approved, in transit, received, refunded, or rejected.
4. Notify on every status change through the app's existing notification and email machinery rather than adding a separate mailer for returns.
5. Do not calculate the refund from the current catalogue price. Use the amounts actually charged on that order, including its discounts, shipping, and tax, or you will refund the wrong money.

## UI and UX Requirements

Match the application's existing design system exactly. Reuse its components,
spacing, and typography. This feature should look like it was always there.

## Responsive Requirements

Works on mobile, tablet, and desktop. Touch targets are large enough to hit on a
phone, and nothing overflows horizontally at 320px.

## Accessibility Requirements

- Fully keyboard navigable.
- Correct semantic elements and ARIA roles.
- Visible focus states.
- Meets WCAG AA contrast.
- Dynamic changes are announced to screen readers.
- Respects prefers-reduced-motion.

## Edge Cases

- Eligibility is per item, not per order. Enforce the return window and any item-level rules such as final sale or perishables at the point of selection, and explain why an item cannot be returned rather than hiding it.
- Partial returns are the normal case. A customer returning two of three units must leave the rest of the order intact, and items already refunded must be excluded from a second request.
- The same line item must not be claimed twice. Reserve the requested quantity when the request is created so a duplicate request cannot be opened in another tab.
- Order-level discounts have to be apportioned across the returned items, otherwise a customer returning one item from a discounted order gets back more than they paid.
- A rejected return needs a stated reason and a next step, and a return that is approved but never arrives needs an expiry after which the request closes on its own rather than sitting open forever.
- Refunding shipping is a policy decision, not an implementation detail. Make it explicit and apply it the same way every time.
- Guest orders need a way in. Verify by order number and email rather than requiring the customer to create an account to return something.
- A refund issued through the payment provider can fail or arrive days later. Record the provider's own state and never mark the request refunded until the provider confirms it.

## Testing

Exercise the feature end to end in the running application. Cover every edge case
above, then run the existing test suite and confirm nothing regressed.

## Acceptance Criteria

- [ ] A customer can open a return from an order and select specific items and quantities.
- [ ] Ineligible items are shown as ineligible with the reason, not silently omitted.
- [ ] The same line item cannot be included in two open requests.
- [ ] The refund amount matches what was charged for those items including apportioned discounts.
- [ ] Every status change is visible to the customer and triggers a notification.
- [ ] Rejected and abandoned returns reach a terminal state rather than staying open indefinitely.
- [ ] Receipts and invoices remain available after a refund and show the adjustment.
- [ ] The feature matches the existing design system.
- [ ] No existing functionality is broken.

## Adaptation Rules

- Match the existing design system. Do not introduce a new colour palette,
  spacing scale, or component library.
- Reuse existing components and utilities wherever they fit.
- Follow the naming, file layout, and code style already present.
- Do not upgrade, replace, or remove existing dependencies to make this
  feature fit. Adapt the feature to the app, not the app to the feature.
- Do not break existing functionality. If a change is genuinely required in
  existing code, make the smallest one that works and say so.
- If something in these instructions conflicts with how the application is
  built, follow the application and explain the deviation.

## Final Verification

Before you report the work as done:

1. Re-read the acceptance criteria above and check each one against what you
   actually built.
2. Run the application and exercise the feature end to end.
3. Run the existing test suite and confirm you have broken nothing.
4. Check the feature on mobile, tablet, and desktop widths.
5. Check keyboard navigation and focus handling.
6. Summarize what changed: files added, files modified, and anything you
   deliberately did differently because of how this application is built.

If any acceptance criterion is unmet, fix it before reporting completion.