Metric picker

// Copyright (c) 2026 Bruno Delorence. MIT License.'use client';import {  useEffect,  useId,  useLayoutEffect,  useRef,  useState,  type KeyboardEvent,  type PointerEvent,} from 'react';import { Chart, seriesOf } from './chart';import { coneAt, inTriangle, locate, type Layout, type Point } from './cone';import { DemoPointer, runDemo } from './demo-pointer';import { Calendar, ChevronRight, Plus, Selector, SourceIcon } from './icons';import { SOURCES, filterSources, type MetricValue, type Source, type SourceGroup } from './metrics';import { useAutoplay } from './use-autoplay';import styles from './metric-picker.module.css';/* * Metric picker: the metric control of an analytics dashboard. The trigger opens a popover with a * search field, the sources of data in groups, and at their right the metrics of the lit source.

/* Metric picker (metric-picker.tsx): a dashboard stage, the label and the toolbar on top, a   faint line chart under them, and the picker's popover over the chart. Sizes are in em of the   stage's text, 14px wherever the popover fits at full width, down to 11px on a phone.   The stage is one layout boundary of a set height: what changes while the demo plays (the lit   rows, the submenu's rows, the trigger's words) lays out the stage alone. The cone is a plain box   cut by a clip-path, and the pointer moves on a small layer of its own.   Colours are the tokens below, light-dark(light, dark) where the two differ: the component takes   the color-scheme it inherits from the page (light unless the page says otherwise), or the one   its colorScheme prop sets (data-color-scheme). */.root {  /* The stage, which the tools share, its edge, and the popover raised over it (and its key). */  --surface: #fff;  --edge: rgb(0 0 0 / 0.06);  --surface-2: #fff;  /* The trigger hovered or open, and the lit row in the popover. */  --hover: #fafafa;  --lit: #f0f0f0;  /* The words: the picks and values; the tools' words and icons; the quiet ones (the axis, the     groups, the placeholder); the label; the rows' icons and the key's word. */  --ink: #171717;  --ink-soft: #666;

/* * The prediction cone, in the popover's own px. While the pointer is in the list, the cone runs * from just behind it to the submenu's near edge: the top of its first row and the bottom of the * column. A pointer whose next position is still inside the cone, and still heading right, is on * its way to the submenu, so the rows it crosses are left alone. * * Near the submenu the cone is thin around the pointer, and a hand that drifts a pixel up or down * would leave it. So its apex steps back behind the pointer, by a buffer that grows as the * pointer closes in: nothing at the far side of the list, most of a row's height at the edge. * * Every box comes from the layout measured once when the popover opens (or when a search changes * its rows): following the pointer is arithmetic on those numbers, never a read of the page. */export type Point = { x: number; y: number };/** The popover's boxes, in its own px, as measured when it opened. */export type Layout = {  /** The list's column: its left edge, and where the rows start. */  listLeft: number;  listTop: number;  /** The submenu's column: its near edge, the top of its first row, its right edge. */  subLeft: number;  subTop: number;

/* * What the picker offers: sources of data in groups, and the metrics each source can chart. A * source opens its metrics at the right of the list; the trigger names the pick as "<source> * <metric>", say "Requests Count". */export type IconName =  'globe' | 'image' | 'revalidate' | 'function' | 'gateway' | 'outbound' | 'blocked' | 'firewall';export type Metric = {  /** Unique within its source. */  id: string;  label: string;};export type Source = {  /** Unique across the picker. */  id: string;  label: string;  icon: IconName;  metrics: Metric[];};export type SourceGroup = {

import { Clock } from './icons';import styles from './metric-picker.module.css';/* * The faint line chart under the picker. It is scenery, so it is hidden from screen readers. Each * metric draws one of a few series, all drawn up front from a fixed seed (the server and the page * draw the same); picking a metric swaps the series on show by its visibility, and nothing inside * an SVG changes. */const SERIES = 5;const POINTS = 72;/** A small seeded generator: the same numbers on every run. */function seeded(seed: number) {  let state = seed;  return () => {    state = (state * 1664525 + 1013904223) % 4294967296;    return state / 4294967296;  };}/** A jagged line in the upper part of a 100 × 100 box. */function series(seed: number) {

import type { ReactNode } from 'react';import type { IconName } from './metrics';/* * The picker's line icons, drawn on a 16 px grid with the text's colour. They are decorative: * every one sits next to the words it stands for. */function Icon({ className, children }: { className?: string; children: ReactNode }) {  return (    <svg      className={className}      viewBox="0 0 16 16"      fill="none"      stroke="currentColor"      strokeWidth="1.2"      strokeLinecap="round"      strokeLinejoin="round"      aria-hidden="true"    >      {children}    </svg>  );}

'use client';import type { CSSProperties, Ref } from 'react';/* * The demo's pointer, and the steps that move it. The picker follows the pointer on every frame, * as it follows a mouse, so each glide is a requestAnimationFrame loop that places the arrow and * hands the picker its position on screen; nothing runs between steps. Stopping the demo (the * reader takes over, or it scrolls away) ends the step in progress at once: its promise rejects, * which ends the script right there, and the pointer fades out. * * The arrow is an HTML box around a still drawing that moves by its transform: a change of style * on an SVG element would lay that SVG out again on every frame. */export type Point = { x: number; y: number };export type Demo = {  /** Resolves after `ms`. */  wait: (ms: number) => Promise<void>;  /** The point at a share of `target`'s width and height, in the stage's px. */  pointOn: (target: Element | null | undefined, x: number, y: number) => Point | null;  /**   * Glides the pointer to `to` (in the stage's px) over `ms`, along a path bent sideways by

'use client';import { useCallback, useEffect, useRef, useState } from 'react';/* * When a demo may play on its own: while part of it is on screen and the tab is visible, never * under reduced motion, and not while the reader is using it. `take()` hands it to the reader; it * takes back over `idle` ms after their last input. */export function useAutoplay<T extends HTMLElement>(idle = 6000) {  const ref = useRef<T>(null);  const [visible, setVisible] = useState(false);  const [reduced, setReduced] = useState(true);  const [taken, setTaken] = useState(false);  const timer = useRef(0);  useEffect(() => {    const element = ref.current;    if (!element) return;    let onScreen = false;    const update = () => setVisible(onScreen && !document.hidden);    const observer = new IntersectionObserver(      ([entry]) => {        onScreen = entry.isIntersecting;