# Quiet Hours

## Objective

Hold non-urgent notifications until the user actually wants to hear from you.

A per-user window during which outbound notifications are suppressed, with an explicit rule for what happens to anything that arrives inside it.

## 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. Extend the existing notification pipeline with a suppression check at send time. Do not build a second notification system.
2. Let the user set a start and end time and store the time zone the window was defined in.
3. Decide per notification type whether it is deferred to the end of the window, dropped entirely, or allowed through as urgent — and record that decision in the notification's definition, not in scattered call sites.
4. Deliver deferred messages as a single digest when the window ends, not as a burst of twenty separate pushes.
5. Do NOT let quiet hours suppress security messages — password changes, new sign-ins, billing failures. A user who cannot be reached about account compromise is worse off than one who was woken up.

## 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

- Evaluate the window against the user's current time zone, not the server's and not the one they signed up in.
- A window that crosses midnight (22:00 to 07:00) is the common case, not the exception. Handle it first.
- Daylight-saving shifts can make a window an hour shorter or longer, and can make a deferred send time occur twice or not at all.
- A deferred notification about a record that was since deleted or resolved must be dropped, not delivered stale.
- Ten deferred notifications about the same record must collapse into one on release.
- Turning quiet hours off mid-window should release the queue immediately, not wait for the original end time.

## 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

- [ ] Non-urgent notifications sent inside the window are not delivered during it.
- [ ] Windows crossing midnight behave correctly.
- [ ] The window is evaluated in the user's current time zone and survives daylight-saving changes.
- [ ] Each notification type has a declared behaviour: defer, drop, or bypass.
- [ ] Deferred messages arrive as one digest, with stale entries removed.
- [ ] Security and billing notifications always bypass the window.
- [ ] 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.