# Date Compare (Lumen Halo): prompt.md (v1.0.0)

- id: `lumen-date-compare` · version 1.0.0 · component · pro (All-Access)
- category: Data
- build: Base UI (one set of files; its dependencies follow the build)
- install (this build): `npx shadcn@latest add @beautiful-ui-pro/lumen-date-compare`
- npm dependencies: react-day-picker@^10
- registry dependencies: utils, @beautiful-ui-pro/lumen-calendar, @beautiful-ui-pro/lumen-popover, @beautiful-ui-pro/lumen-sheet, @beautiful-ui/lumen-button, https://beautiful-ui.dev/r/lumen-foundation.json
- docs: https://beautiful-ui.dev/components/lumen-date-compare
- The install command carries everything this item needs (files, CSS, tokens, npm and registry dependencies). Prefer it to copying source by hand.

Pick the dates and what to compare them with. The trigger reads the way people say it ("Last 30 days · vs Aug 2 – 31"); the calendar shows both ranges, the comparison as outlined days; previous period, previous year or custom; Apply commits once. Time-zone safe: ISO days, and today in the workspace's zone.

## Build it
- Stack: React 19 (`ref` is a plain prop), TypeScript, Tailwind CSS v4 utilities, a shadcn-initialised project with the `@/*` alias.
- Packages: `react-day-picker@^10`.
- Files: `components/ui/lumen/controls/date-compare.tsx`; shared code: `lib/beautiful-ui/core/date-ranges.ts`.
- Registry dependencies, installed with it automatically: shadcn `utils` (cn), `lumen-calendar`, `lumen-popover`, `lumen-sheet`, `lumen-button`, `lumen-foundation`.
- Builds: one set of files for both, but its dependencies come in Base UI and Radix builds. Install the one that matches the project (see Install): a free item's bare URL installs the Base UI build of it and its dependencies.
- Exports to keep: `DateCompare`, and every exported type.
- CSS: the install merges this item's rules (the registry `css` field) into your global stylesheet, in `@layer components`, and adds the lumen foundation (tokens, keyframes, motion levels) once. Nothing to import by hand.
- Re-running `add` (or `--overwrite`) re-applies those rules: put overrides in your own CSS, never in the installed rules.
- Tokens: retheme with the `--lumen-*` custom properties (`--lumen-accent`, `--lumen-accent-text`, `--lumen-bad`, `--lumen-bad-text`, `--lumen-focus`, `--lumen-good`, `--lumen-good-text`, `--lumen-hairline`, `--lumen-ink`, `--lumen-muted-ink`, `--lumen-series-1`, `--lumen-series-2`, `--lumen-series-3`, `--lumen-series-4`, `--lumen-series-5`, `--lumen-series-6`, `--lumen-warn`, `--lumen-warn-text`); this item's CSS also reads `--lumen-font-mono`, `--lumen-font-sans`, `--lumen-radius-k`. Never add Tailwind colour classes inside the component.

```tsx
import { DateCompare } from "@/components/ui/lumen/controls/date-compare";
```

## Parts

| Part | data-slot | What it is for |
|---|---|---|
| `DateCompare` | — | The trigger, presets, calendar, compare modes and Apply. |

## Sound
- Keep every `data-slot` and `data-sound` attribute: the sound layer reads them.
- Installing this item adds no audio. Nothing plays until the app mounts `GlassSoundProvider` once (install: `npx shadcn@latest add https://beautiful-ui.dev/r/glass-sound.json`, import from `@/components/beautiful-ui/glass-sound`); `GlassSoundToggle` is its mute control. Without a provider the audio engine never loads.

## Match the original
- Read `components/ui/lumen/controls/date-compare.tsx` as the reference implementation before changing or recreating anything, and match it: sizes, colours per theme, motion timings, copy and behaviour.
- If you deviate (a prop you can't honour, a style you changed, a dependency you swapped), say so in your reply, part by part.
- Keep the accessibility contract, the keyboard map and the motion levels listed below.

## Use it when
- date compare, date range comparison, previous period, year over year, period picker, dashboard dates, Lumen
- Dashboards and reports that compare a period with the one before, or with last year

### Not when
- Picking one date: use Date Picker
- A range filter on a table: use the Filter Bar's date field

## Mistakes
- Pass the workspace's timeZone, or "today" follows each viewer's clock
- Fetch comparisonRange(value), not a range you work out yourself, so charts and headers agree

## Usage

```tsx
import { DateCompare } from "@/components/ui/lumen/controls/date-compare";
import { comparisonRange, datePresets, todayIn } from "@/lib/date-compare";

const [value, setValue] = useState({ range: datePresets(todayIn("Europe/London"))[1].range, compare: "previous-period" });
<DateCompare value={value} onValueChange={setValue} timeZone="Europe/London" />
// fetch(value.range) and fetch(comparisonRange(value))
```

## Props

| Prop | Type | Default | What it does |
|---|---|---|---|
| `value / onValueChange` | `{ range, compare, custom? }` |  | ISO day ranges (inclusive) and the comparison mode; onValueChange fires on Apply. |
| `timeZone` | `string` |  | The workspace's zone, for what today means in the presets. Default: the viewer's. |
| `locale` | `string` |  | How dates read. |
| `presets` | `{ id, label, range }[]` |  | Your own presets; default: last 7/30/90 days, month to date, last month, quarter, year to date, last 12 months. |
| `numberOfMonths` | `number` | `2` | Months shown side by side. |
| `labels` | `Partial<Labels>` |  | Every word, for i18n. |
| `comparisonRange(value)` | `(value) => DayRange \| null` |  | From core/lib/date-ranges: the dates to fetch for the comparison. |

Full docs: https://beautiful-ui.dev/components/lumen-date-compare

## Customising
- Colours: set the `--lumen-*` tokens on `:root`, or on a container with the `lumen-scope` class to retheme one area. Add the `lumen-inherit` class to follow your shadcn palette instead (`--chart-N`, `--destructive`).
- Dark mode follows the `.dark` class on an ancestor (the shadcn and next-themes convention).
- Update later by re-running the install with `--overwrite` (review the diff if you edited it). Changelog: https://beautiful-ui.dev/r/changelog.json

## Keyboard

| Keys | Action |
|---|---|
| Enter / Space | Open, pick a preset, a day or a mode |
| Arrows | Move between days |
| Escape | Close without applying |

## Motion inventory

| Interaction | What moves |
|---|---|
| Open | The floating glass grows from the trigger |

## Accessibility contract (preserve when editing)
- The trigger names the range and the comparison
- Compare modes are a radio group
- The calendar is Lumen Calendar's grid; the hint says whether you're picking the range or the comparison
- Changes apply on Apply, so screen readers aren't flooded with refetches

## Install

```bash
npx shadcn@latest add @beautiful-ui-pro/lumen-date-compare
```

Pro item: needs the `@beautiful-ui-pro` registry in `components.json` and `BEAUTIFUL_UI_TOKEN` in `.env.local` (https://beautiful-ui.dev/account). Setup: https://beautiful-ui.dev/docs/pro. Your components.json `style` picks the build: radix-*, new-york and default get Radix, base-* gets Base UI.

## Credits
- React DayPicker (https://daypicker.dev)
- Built on shadcn/ui (https://ui.shadcn.com)

The lumen foundation (the tokens listed above, keyframes and motion levels) installs once with the first component; its CSS is public at https://beautiful-ui.dev/r/lumen-foundation.json.