# Trial Extension

## Objective

Let an admin give an account more evaluation time, on the record.

An administrative action that moves a trial's end date, with limits, a reason, and reconciliation against the billing provider.

## 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. Restrict the action to a specific permission, not merely to anyone with admin access. Extending trials is giving away revenue.
2. Require a reason and a fixed duration on every grant. Free-form date entry with no justification produces trials that never end.
3. Enforce a per-account limit on the number and total length of extensions, and refuse a second extension while one is still running.
4. Write an audit record for every grant and every refusal: who, when, how long, why, and the resulting end date.
5. Push the new end date to the billing provider in the same operation. Do NOT build the trial state machine, reminders, or expiry behaviour here — those are owned by Free Trial Lifecycle; this only moves the date it works from.

## 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

- Extensions must not stack into an indefinite trial. Cap the cumulative total, not just each grant.
- If the billing provider rejects the new date, the app must not show the account as extended. Roll back and tell the admin what failed.
- A user who converts to paid during an extension must be charged from the conversion, with the remaining extension days discarded rather than credited.
- Extending an already-expired trial has to explicitly restore entitlements, not just set a future date and hope the next job notices.
- The user needs to be told their trial was extended, or they will still act on the old expiry warning they already received.
- Two admins extending at once must not both apply. Serialise the write and make the second attempt fail visibly.
- An extension granted on a cancelled trial should be refused, not silently create an active trial the user did not ask for.

## 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

- [ ] Only holders of a specific permission can grant an extension.
- [ ] Every grant requires a duration and a reason, and both are stored.
- [ ] Per-account count and cumulative-length limits are enforced, and overlapping extensions are refused.
- [ ] An audit record names who granted it, when, why, and the new end date.
- [ ] The billing provider's trial end date matches the app's, or the grant fails and rolls back.
- [ ] The affected user is notified of the new end date.
- [ ] Conversion or cancellation during an extension is handled without leftover trial days.
- [ ] 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.