milestone 30: overview as a dashboard, explicit health contract, period aggregations

admin/src/features/diagnostics/HealthStrip.tsx

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+/**
+ * The five health conditions, compactly, at the top of the page that explains
+ * failures. Healthy conditions stay quiet; a degraded one is highlighted and
+ * offers the way out.
+ *
+ * A degraded condition whose explanation is on this page narrows this page
+ * rather than navigating away: the filter link sets `component` and drops every
+ * other filter. A time window, a severity or a `state=resolved` left from an
+ * earlier investigation would each hide the very episode the reader was sent to
+ * read, and a link that lands on "no events" states something false.
+ *
+ * The load contract is the one the deleted Overview status section carried: a
+ * visible loading state before the first reading, and a refetch failure that
+ * says so — the conditions on screen become the last reading that arrived, never
+ * a claim about the current state, until a poll succeeds again.
+ */
+
+import { useQuery } from "@tanstack/react-query";
+import { Link } from "@tanstack/react-router";
+import * as stylex from "@stylexjs/stylex";
+import InlineError from "@/lib/InlineError";
+import { healthQuery } from "@/lib/queries";
+import { styles as shared } from "@/ui/styles";
+import { colors } from "@/ui/tokens.stylex";
+import { healthFacts, type FactLink, type FactTone, type HealthFact } from "./healthFacts";
+
+const DARK = "@media (prefers-color-scheme: dark)";
+
+const styles = stylex.create({
+	list: {
+		marginTop: "0.75rem",
+		display: "grid",
+		gap: "0.5rem",
+		// Five is prime, so every count between one and five leaves a short last
+		// row; three columns made it 3 then 2, which reads as a layout that ran out
+		// of room rather than one that chose. So the strip goes from one column
+		// straight to two and then to a single row of five, and is never ragged.
+		gridTemplateColumns: {
+			default: "minmax(0, 1fr)",
+			"@media (min-width: 640px)": "repeat(2, minmax(0, 1fr))",
+			"@media (min-width: 1100px)": "repeat(5, minmax(0, 1fr))",
+		},
+		listStyleType: "none",
+		padding: 0,
+	},
+	fact: {
+		display: "flex",
+		flexWrap: "wrap",
+		alignItems: "baseline",
+		gap: "0.375rem",
+		borderRadius: "0.25rem",
+		borderWidth: 1,
+		borderStyle: "solid",
+		paddingInline: "0.625rem",
+		paddingBlock: "0.5rem",
+		fontSize: "0.875rem",
+		lineHeight: "1.25rem",
+	},
+	/** Quiet: a healthy condition is the normal state and gets no emphasis. */
+	quiet: {
+		borderColor: colors.border,
+		backgroundColor: "transparent",
+	},
+	highlighted: {
+		borderColor: colors.borderStrong,
+		backgroundColor: colors.surfaceRaised,
+	},
+	label: {
+		color: colors.textSecondary,
+	},
+	value: {
+		fontWeight: 500,
+	},
+	detail: {
+		flexBasis: "100%",
+		fontSize: "0.75rem",
+		lineHeight: "1rem",
+		color: colors.textMuted,
+	},
+	link: {
+		fontSize: "0.875rem",
+		lineHeight: "1.25rem",
+		color: colors.primaryOnSurface,
+		textDecorationLine: "none",
+	},
+	ok: {
+		color: { default: "oklch(43.2% 0.095 166.913)", [DARK]: "oklch(84.5% 0.143 164.978)" },
+	},
+	notice: {
+		color: { default: "oklch(47.3% 0.137 46.201)", [DARK]: "oklch(87.9% 0.169 91.605)" },
+	},
+	warn: {
+		color: { default: "oklch(47.3% 0.137 46.201)", [DARK]: "oklch(87.9% 0.169 91.605)" },
+	},
+	danger: {
+		color: colors.dangerText,
+	},
+	message: {
+		marginTop: "0.5rem",
+		fontSize: "0.875rem",
+		lineHeight: "1.25rem",
+		color: colors.textMuted,
+	},
+});
+
+const TONES = { ok: styles.ok, notice: styles.notice, warn: styles.warn, danger: styles.danger } as const;
+
+/** Text and icon carry the state; the colour only agrees with them. */
+const ICONS: Record<FactTone, string> = { ok: "●", notice: "‖", warn: "!", danger: "✕" };
+
+function FactLinkAnchor({ link }: { link: FactLink }) {
+	if (link.kind === "filter") {
+		return (
+			<Link
+				to="/diagnostics"
+				// Sets the component and clears every filter that could hide what it
+				// points at: a time window from an older investigation, and a severity
+				// or state — `resolved` above all — that would exclude the very episode
+				// explaining the condition this link came from.
+				search={() => ({ component: link.component })}
+				{...stylex.props(styles.link, shared.focusRing)}
+			>
+				{link.label}
+			</Link>
+		);
+	}
+	return (
+		<Link to={link.to} {...stylex.props(styles.link, shared.focusRing)}>
+			{link.label}
+		</Link>
+	);
+}
+
+function Fact({ fact }: { fact: HealthFact }) {
+	return (
+		<li {...stylex.props(styles.fact, fact.tone === "ok" ? styles.quiet : styles.highlighted)}>
+			<span aria-hidden="true" {...stylex.props(TONES[fact.tone])}>
+				{ICONS[fact.tone]}
+			</span>
+			<span {...stylex.props(styles.label)}>{fact.label}</span>
+			<span {...stylex.props(styles.value, TONES[fact.tone])}>{fact.value}</span>
+			{fact.link !== undefined && <FactLinkAnchor link={fact.link} />}
+			{fact.detail !== undefined && <span {...stylex.props(styles.detail)}>{fact.detail}</span>}
+		</li>
+	);
+}
+
+export default function HealthStrip() {
+	const health = useQuery(healthQuery());
+
+	if (health.data === undefined) {
+		return health.isError ? (
+			<InlineError error={health.error} onRetry={() => void health.refetch()} />
+		) : (
+			<p role="status" {...stylex.props(styles.message, shared.pulse)}>
+				Loading status…
+			</p>
+		);
+	}
+
+	return (
+		<>
+			<ul aria-label="Current status" {...stylex.props(styles.list)}>
+				{healthFacts(health.data).map((fact) => (
+					<Fact key={fact.key} fact={fact} />
+				))}
+			</ul>
+			{health.isError && (
+				<>
+					<p role="status" {...stylex.props(styles.message)}>
+						This is the last reading that arrived. The current state is unknown.
+					</p>
+					<InlineError error={health.error} onRetry={() => void health.refetch()} />
+				</>
+			)}
+		</>
+	);
+}