Incident Response

patterns/incident-response/index.ts

export { IncidentResponse } from "./incident-response";
export { IncidentResponseDemo } from "./demo";
export { createIncidentSnapshot } from "./fixtures";
export { applyIncidentAction, prioritizeIncidents, validateIncidentText } from "./incident-state";
export type {
  IncidentStatus,
  IncidentAction,
  IncidentCase,
  IncidentSnapshot,
  IncidentActionRequest,
  IncidentActionResult,
  IncidentResponseProps,
} from "./types";

patterns/incident-response/incident-response.tsx

"use client";

import { useId, useLayoutEffect, useRef, useState } from "react";
import {
  Badge,
  Button,
  EntityPreview,
  Field,
  Input,
  Select,
  SelectOption,
  Textarea,
} from "@operator-ds/react";
import { formatUtcInstant } from "../operational-domain";
import { prioritizeIncidents, validateIncidentText } from "./incident-state";
import type {
  IncidentAction,
  IncidentActionResult,
  IncidentCase,
  IncidentResponseProps,
  IncidentSnapshot,
} from "./types";

const focus =
  "outline-none focus-visible:border-oprt-border-focus focus-visible:shadow-oprt-focus forced-colors:focus-visible:outline forced-colors:focus-visible:outline-2";
const sectionTitle = "m-0 text-oprt-base font-semibold uppercase tracking-oprt-caps";
const statusLabel = { new: "New", acknowledged: "Acknowledged", resolved: "Resolved" };
const priorityLabel = { 1: "High", 2: "Medium", 3: "Low" };
const isoOf = (at: number) => new Date(at).toISOString();
/** "YYYY-MM-DD HH:MM:SS UTC". Case times are minutes, so milliseconds are never shown. */
const stamp = (at: number) => formatUtcInstant(isoOf(at), { milliseconds: "never" });

/** A time with its date and zone. A narrow column breaks between the date and the time, never inside either. */
function Stamp({ at, className }: { at: number; className?: string }) {
  const text = stamp(at);
  return (
    <time dateTime={isoOf(at)} {...(className ? { className } : {})}>
      <span className="inline-block">{text.slice(0, 10)}</span>{" "}
      <span className="inline-block">{text.slice(11)}</span>
    </time>
  );
}

/**
 * The queue is tight, so a case opened on the day of the snapshot shows only "HH:MM UTC". An
 * earlier one carries its date above the time, so a handover across midnight is not mistaken for today.
 */
function QueueTime({ at, today }: { at: number; today: string }) {
  const text = stamp(at);
  const date = text.slice(0, 10);
  return (
    <time dateTime={isoOf(at)} className="text-right font-mono text-oprt-text-dim">
      {date !== today && <span className="block">{date}</span>}
      <span className="inline-block">{text.slice(11, 16)} UTC</span>
    </time>
  );
}

interface CaseSession {
  editor: "assign" | "note" | "resolve" | null;
  revision: number;
  text: string;
  ownerId: string;
  fieldError: string | undefined;
  result: IncidentActionResult | null;
  pending: boolean;
}

function createCaseSession(item: IncidentCase, operatorId: string): CaseSession {
  return {
    editor: null,
    revision: item.revision,
    text: "",
    ownerId: item.ownerId ?? operatorId,
    fieldError: undefined,
    result: null,
    pending: false,
  };
}

/** Queue selection and canonical case data belong to the application. */
export function IncidentResponse(props: IncidentResponseProps) {
  // A replaced source remounts local filters and drafts, including in-flight feedback.
  return <IncidentWorkspace key={props.snapshot.id} {...props} />;
}

function IncidentWorkspace({
  snapshot,
  selectedId,
  onSelectedIdChange,
  onAction,
}: IncidentResponseProps) {
  const [scope, setScope] = useState<"open" | "all">("open");
  const [query, setQuery] = useState("");
  const [sessions, setSessions] = useState(() => new Map<string, CaseSession>());
  const [selectionRequest, setSelectionRequest] = useState<string | null>(null);
  const detailsRef = useRef<HTMLElement>(null);
  const filterId = useId();
  const selected = snapshot.cases.find((item) => item.id === selectedId);
  const open = snapshot.cases.filter((item) => item.status !== "resolved").length;
  const visible = prioritizeIncidents(snapshot.cases).filter(
    (item) =>
      (scope === "all" || item.status !== "resolved") &&
      `${item.id} ${item.title} ${item.location}`
        .toLowerCase()
        .includes(query.trim().toLowerCase()),
  );
  const operator = snapshot.owners.find((owner) => owner.id === snapshot.operatorId);
  const today = isoOf(snapshot.observedAt).slice(0, 10);

  function updateSession(item: IncidentCase, patch: Partial<CaseSession>) {
    // Each callback retains its case identity, including after selection changes.
    setSessions((current) =>
      new Map(current).set(item.id, {
        ...(current.get(item.id) ?? createCaseSession(item, snapshot.operatorId)),
        ...patch,
      }),
    );
  }

  useLayoutEffect(() => {
    if (selectionRequest && selectedId === selectionRequest) detailsRef.current?.focus();
    if (selectionRequest) setSelectionRequest(null);
  }, [selectedId, selectionRequest]);

  return (
    <section
      aria-label="Incident response workspace"
      className="not-prose w-full min-w-0 border border-oprt-border bg-oprt-surface-1 font-sans text-oprt-base text-oprt-text"
    >
      <header className="flex flex-wrap items-start justify-between gap-2u border-b border-oprt-border px-3u py-2u">
        <div className="min-w-0">
          <h2 className="m-0 text-oprt-lg font-semibold normal-case tracking-normal">
            {snapshot.title}
          </h2>
          <p className="m-0 mt-0.5u text-oprt-text-dim">{snapshot.location}</p>
        </div>
        <div className="text-right text-oprt-text-dim">
          <p className="m-0">{operator?.name ?? "Operator unavailable"}</p>
          <p className="m-0 mt-0.5u font-mono">
            Snapshot · <Stamp at={snapshot.observedAt} />
          </p>
        </div>
      </header>
      <div className="flex min-w-0 flex-wrap">
        <section
          aria-label="Incident queue"
          className="min-w-0 flex-[1_1_14rem] border-b border-oprt-border"
        >
          <div className="flex flex-col gap-2u border-b border-oprt-border p-2u">
            <div className="flex items-baseline justify-between gap-2u">
              <h3 className={sectionTitle}>Incident queue</h3>
              <span className="font-mono text-oprt-text-dim">{open} open</span>
            </div>
            <div role="group" aria-label="Queue scope" className="flex flex-wrap gap-1u">
              <Button
                size="sm"
                variant={scope === "open" ? "secondary" : "ghost"}
                aria-pressed={scope === "open"}
                onClick={() => setScope("open")}
              >
                Open cases
              </Button>
              <Button
                size="sm"
                variant={scope === "all" ? "secondary" : "ghost"}
                aria-pressed={scope === "all"}
                onClick={() => setScope("all")}
              >
                All cases · {snapshot.cases.length}
              </Button>
            </div>
            <label className="sr-only" htmlFor={filterId}>
              Find a case
            </label>
            <Input
              id={filterId}
              placeholder="Find a case or location"
              value={query}
              onChange={(event) => setQuery(event.target.value)}
            />
          </div>
          <ol
            className="m-0 max-h-[min(40rem,70dvh)] list-none overflow-y-auto p-0"
            aria-label="Cases by priority"
          >
            {visible.map((item) => {
              const ownerName = item.ownerId
                ? (snapshot.owners.find((owner) => owner.id === item.ownerId)?.name ??
                  "Owner unavailable")
                : "Unassigned";
              const isSelected = item.id === selectedId;
              return (
                <li key={item.id} className="border-b border-oprt-border last:border-b-0">
                  <button
                    type="button"
                    aria-pressed={isSelected}
                    // The name opens with the ID and title and then carries every other visible
                    // part, so it holds what the button shows (WCAG 2.5.3) in the same order.
                    aria-label={`${item.id} · ${item.title}, P${item.priority} · ${priorityLabel[item.priority]}, ${item.location}, ${statusLabel[item.status]} · ${ownerName}, opened ${stamp(item.openedAt)}`}
                    onClick={() => {
                      setSelectionRequest(item.id);
                      onSelectedIdChange(item.id);
                    }}
                    // The selected case also gets a bar down its edge. The tint alone is about 1.1:1
                    // against the panel, and a bar survives the focus ring, which is a box-shadow.
                    className={`relative flex w-full min-w-0 flex-col gap-1u border border-transparent p-2u text-left text-oprt-base hover:bg-oprt-surface-2 ${focus} ${isSelected ? "bg-oprt-surface-3 before:absolute before:inset-y-0 before:left-0 before:w-[3px] before:bg-oprt-accent forced-colors:before:bg-[Highlight]" : "bg-transparent"}`}
                  >
                    <span className="flex w-full flex-wrap items-baseline justify-between gap-1u">
                      <span className="font-mono text-oprt-text-dim">{item.id}</span>
                      <Badge
                        appearance="text"
                        variant={
                          item.priority === 1 && item.status !== "resolved" ? "warning" : "neutral"
                        }
                      >
                        P{item.priority} · {priorityLabel[item.priority]}
                      </Badge>
                    </span>
                    <span className="text-oprt-md font-semibold normal-case leading-snug">
                      {item.title}
                    </span>
                    <span className="text-oprt-text-dim">{item.location}</span>
                    <span className="flex w-full flex-wrap items-center justify-between gap-1u">
                      <span className="text-oprt-text-dim">
                        {statusLabel[item.status]} · {ownerName}
                      </span>
                      <QueueTime at={item.openedAt} today={today} />
                    </span>
                  </button>
                </li>
              );
            })}
          </ol>
          {visible.length === 0 && (
            <p className="m-0 p-3u text-oprt-text-dim">
              No cases match this queue. Change the filter or choose All cases.
            </p>
          )}
          {selected && !visible.some((item) => item.id === selectedId) && (
            <p className="m-0 border-t border-oprt-border p-2u text-oprt-text-dim">
              The selected case is outside this queue.
            </p>
          )}
          <p className="m-0 border-t border-oprt-border p-2u text-oprt-text-dim">
            Highest priority first · oldest report first
          </p>
        </section>
        <section
          ref={detailsRef}
          aria-label="Selected case"
          tabIndex={-1}
          className={`min-w-0 flex-[2.4_1_25rem] border border-transparent border-l-oprt-border p-3u ${focus}`}
        >
          {selected ? (
            <CaseWorkspace
              key={selected.id}
              snapshot={snapshot}
              item={selected}
              session={
                sessions.get(selected.id) ?? createCaseSession(selected, snapshot.operatorId)
              }
              onSessionChange={(patch) => updateSession(selected, patch)}
              {...(onAction ? { onAction } : {})}
            />
          ) : (
            <div className="flex flex-col gap-1u">
              <h3 className="m-0 text-oprt-md font-semibold">
                {selectedId ? "Case unavailable" : "Select a case"}
              </h3>
              <p className="m-0 text-oprt-text-dim">
                {selectedId
                  ? "This case is no longer in the supplied queue. Choose another case to continue."
                  : "Choose a case from the queue to review its evidence and next action."}
              </p>
            </div>
          )}
        </section>
      </div>
    </section>
  );
}

function CaseWorkspace({
  snapshot,
  item,
  session,
  onSessionChange,
  onAction,
}: {
  snapshot: IncidentSnapshot;
  item: IncidentCase;
  session: CaseSession;
  onSessionChange: (patch: Partial<CaseSession>) => void;
  onAction?: IncidentResponseProps["onAction"];
}) {
  const { editor, revision, text, ownerId, fieldError, result, pending } = session;
  const actionRef = useRef<HTMLButtonElement>(null);
  const assignOpenerRef = useRef<HTMLButtonElement>(null);
  const noteOpenerRef = useRef<HTMLButtonElement>(null);
  const assignmentRef = useRef<HTMLButtonElement>(null);
  // The control that opened the editor, so closing it puts focus back where the operator was.
  const opener = useRef<"primary" | "assign" | "note">("primary");
  const returnFocus = useRef(false);
  const owner = snapshot.owners.find((person) => person.id === item.ownerId);
  const actionsUnavailable = !onAction
    ? "Case updates are unavailable in this workspace."
    : (item.unavailableReason ??
      (Object.values(item.permissions).some((value) => !value)
        ? "Your access does not include all case actions."
        : undefined));
  const disabled = (action: IncidentAction["type"]) =>
    pending || !onAction || !item.permissions[action] || result?.kind === "conflict";
  const primaryAction =
    item.status === "new" ? "acknowledge" : item.status === "acknowledged" ? "resolve" : "note";
  const primaryLabel =
    item.status === "new"
      ? "Acknowledge case"
      : item.status === "acknowledged"
        ? "Resolve case"
        : "Add handover";

  useLayoutEffect(() => {
    if (editor === "assign") assignmentRef.current?.focus();
    if (editor === null && returnFocus.current) {
      const target = { primary: actionRef, assign: assignOpenerRef, note: noteOpenerRef }[
        opener.current
      ].current;
      // A control the case no longer offers (a resolved case has no Assign owner) gives way to
      // the primary action.
      (target?.isConnected && !target.disabled ? target : actionRef.current)?.focus();
      returnFocus.current = false;
    }
  }, [editor, item.status]);

  function edit(next: "assign" | "note" | "resolve", from: "primary" | "assign" | "note") {
    opener.current = from;
    onSessionChange({ ...createCaseSession(item, snapshot.operatorId), editor: next });
  }

  async function act(action: IncidentAction, expectedRevision: number) {
    if (!onAction || pending) return;
    onSessionChange({ pending: true, result: null });
    try {
      const outcome = await onAction({ caseId: item.id, expectedRevision, action });
      if (outcome.kind === "accepted") {
        returnFocus.current = true;
        onSessionChange({ result: outcome, editor: null, text: "", fieldError: undefined });
      } else {
        onSessionChange({ result: outcome });
      }
    } catch {
      onSessionChange({
        result: {
          kind: "rejected",
          message:
            "The action outcome could not be confirmed. Refresh the case from the service before retrying.",
        },
      });
    } finally {
      onSessionChange({ pending: false });
    }
  }

  return (
    <div className="flex min-w-0 flex-col gap-3u">
      <EntityPreview
        headingLevel={3}
        entity={{
          id: item.id,
          name: item.title,
          typeLabel: "Incident case",
          summary: item.summary,
          facts: [
            {
              id: "status",
              label: "Status",
              value: (
                <Badge
                  appearance="text"
                  size="md"
                  variant={item.status === "resolved" ? "success" : "neutral"}
                >
                  {statusLabel[item.status]}
                </Badge>
              ),
            },
            {
              id: "priority",
              label: "Priority",
              value: (
                <Badge
                  appearance="text"
                  size="md"
                  variant={
                    item.priority === 1 && item.status !== "resolved" ? "warning" : "neutral"
                  }
                >
                  P{item.priority} · {priorityLabel[item.priority]}
                </Badge>
              ),
            },
            {
              id: "owner",
              label: "Owner",
              value: owner?.name ?? (item.ownerId ? "Owner unavailable" : "Unassigned"),
            },
            { id: "location", label: "Location", value: item.location },
            {
              id: "opened",
              label: "Opened",
              value: <Stamp at={item.openedAt} />,
              mono: true,
            },
            { id: "revision", label: "Revision", value: `r${item.revision}`, mono: true },
          ],
          quality: { state: item.dataState, source: item.source, updatedAt: item.updatedAt },
        }}
      />

      <div className="flex flex-col gap-2u border-y border-oprt-border py-2u">
        {editor === null ? (
          <div className="flex flex-wrap items-center gap-1u">
            <Button
              ref={actionRef}
              size="sm"
              disabled={disabled(primaryAction)}
              onClick={() => {
                if (primaryAction === "acknowledge")
                  void act({ type: "acknowledge" }, item.revision);
                else edit(primaryAction, "primary");
              }}
            >
              {pending ? "Submitting…" : primaryLabel}
            </Button>
            {item.status !== "resolved" && (
              <Button
                ref={assignOpenerRef}
                size="sm"
                variant="tertiary"
                disabled={disabled("assign")}
                onClick={() => edit("assign", "assign")}
              >
                Assign owner
              </Button>
            )}
            {item.status !== "resolved" && (
              <Button
                ref={noteOpenerRef}
                size="sm"
                variant="ghost"
                disabled={disabled("note")}
                onClick={() => edit("note", "note")}
              >
                Add handover
              </Button>
            )}
          </div>
        ) : (
          <form
            noValidate
            className="flex min-w-0 flex-col gap-2u"
            aria-label={
              editor === "assign"
                ? "Assign case"
                : editor === "note"
                  ? "Add handover"
                  : "Resolve case"
            }
            onSubmit={(event) => {
              event.preventDefault();
              if (editor === "assign") {
                void act({ type: "assign", ownerId }, revision);
                return;
              }
              const error = validateIncidentText(
                text,
                editor === "note" ? "Handover note" : "Resolution reason",
              );
              onSessionChange({ fieldError: error });
              if (!error)
                void act(
                  editor === "note"
                    ? { type: "note", note: text }
                    : { type: "resolve", reason: text },
                  revision,
                );
            }}
          >
            {editor === "assign" ? (
              <Field label="Case owner" required>
                <Select
                  ref={assignmentRef}
                  value={ownerId}
                  onValueChange={(ownerId) => onSessionChange({ ownerId })}
                  disabled={pending}
                  size="sm"
                  className="w-full"
                  required
                >
                  {snapshot.owners.map((person) => (
                    <SelectOption
                      key={person.id}
                      value={person.id}
                    >{`${person.name} · ${person.role}`}</SelectOption>
                  ))}
                </Select>
              </Field>
            ) : (
              <Field
                label={editor === "note" ? "Handover note" : "Resolution reason"}
                required
                help={
                  editor === "note"
                    ? `Record the current condition, outstanding check, and what the next ${snapshot.domain === "military" ? "watch" : "shift"} must follow up.`
                    : "Record what changed and how recovery was verified."
                }
                {...(fieldError ? { error: fieldError } : {})}
              >
                <Textarea
                  autoFocus
                  required
                  rows={3}
                  maxLength={1000}
                  value={text}
                  disabled={pending}
                  onChange={(event) => {
                    onSessionChange({ text: event.target.value, fieldError: undefined });
                  }}
                />
              </Field>
            )}
            <div className="flex flex-wrap gap-1u">
              <Button
                type="submit"
                size="sm"
                disabled={
                  disabled(editor) ||
                  result?.kind === "conflict" ||
                  (editor === "assign" && ownerId === item.ownerId)
                }
              >
                {pending
                  ? "Submitting…"
                  : editor === "assign"
                    ? "Save assignment"
                    : editor === "note"
                      ? "Save handover"
                      : "Confirm resolution"}
              </Button>
              <Button
                size="sm"
                variant="ghost"
                disabled={pending}
                onClick={() => {
                  returnFocus.current = true;
                  onSessionChange({ editor: null, result: null, text: "", fieldError: undefined });
                }}
              >
                Cancel
              </Button>
            </div>
          </form>
        )}
        {actionsUnavailable && <p className="m-0 text-oprt-text-dim">{actionsUnavailable}</p>}
        {result && (
          <div className="flex flex-col gap-1u">
            <p
              role={result.kind === "accepted" ? "status" : "alert"}
              className={`m-0 ${result.kind === "accepted" ? "text-oprt-text-dim" : "text-oprt-error"}`}
            >
              {result.message}
            </p>
            {result.kind === "conflict" && (
              <Button
                className="self-start"
                size="sm"
                variant="tertiary"
                onClick={() => {
                  onSessionChange({ revision: item.revision, result: null });
                }}
              >
                Review latest case
              </Button>
            )}
          </div>
        )}
      </div>

      {item.resolution && (
        <section aria-label="Resolution" className="flex flex-col gap-1u">
          <h4 className={sectionTitle}>Resolution</h4>
          <p className="m-0 leading-relaxed">{item.resolution}</p>
        </section>
      )}

      <section aria-label="Case evidence" className="flex flex-col gap-2u">
        <h4 className={sectionTitle}>Evidence</h4>
        <dl className="m-0 flex min-w-0 flex-col gap-2u">
          {item.evidence.map((entry) => (
            <div
              key={entry.id}
              className="grid min-w-0 grid-cols-[minmax(0,1fr)_auto] gap-x-2u gap-y-0.5u"
            >
              <dt className="font-medium">{entry.label}</dt>
              <dd className="m-0 text-right font-mono">{entry.value}</dd>
              <dd className="col-span-2 m-0 text-oprt-text-dim">
                {entry.detail} <Stamp at={entry.at} className="font-mono" />
              </dd>
            </div>
          ))}
        </dl>
        {item.evidence.length === 0 && (
          <p className="m-0 text-oprt-text-dim">No evidence has been supplied for this case.</p>
        )}
      </section>

      <section
        aria-label="Case history"
        className="flex flex-col gap-2u border-t border-oprt-border pt-3u"
      >
        <div className="flex items-baseline justify-between gap-2u">
          <h4 className={sectionTitle}>Case history</h4>
          <span className="text-oprt-text-dim">Oldest first</span>
        </div>
        <ol className="m-0 flex list-none flex-col gap-3u p-0">
          {[...item.history]
            .sort((a, b) => a.at - b.at)
            .map((event) => (
              <li key={event.id} className="flex min-w-0 flex-wrap gap-x-2u gap-y-0.5u">
                <Stamp at={event.at} className="font-mono text-oprt-text-dim" />
                <div className="min-w-0 flex-[1_1_12rem]">
                  <p className="m-0 font-semibold">{event.label}</p>
                  <p className="m-0 mt-0.5u break-words [overflow-wrap:anywhere]">{event.detail}</p>
                  <p className="m-0 mt-0.5u text-oprt-text-dim">{event.actor}</p>
                </div>
              </li>
            ))}
        </ol>
        {item.history.length === 0 && (
          <p className="m-0 text-oprt-text-dim">No history has been supplied for this case.</p>
        )}
      </section>
    </div>
  );
}

patterns/operational-domain.ts

/** Fixture context used by reusable application recipes. */
export type OperationalDomain = "military" | "industrial";

export interface UtcInstantOptions {
  /**
   * Whether the milliseconds are shown. "auto" (the default) shows them only when the supplied
   * instant carries a non-zero fraction, because sub-second timing matters only where it exists.
   */
  milliseconds?: "auto" | "always" | "never";
}

const INSTANT =
  /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})(?:\.(\d{1,3}))?(Z|[+-]\d{2}:\d{2})$/;

/**
 * Reads an ISO 8601 instant as "YYYY-MM-DD HH:MM:SS UTC", with ".mmm" after the seconds where the
 * options ask for it. Text that is not a real instant (an invented date such as 30 February, or
 * free text) is returned as supplied rather than reinterpreted. It never uses Intl, so the server
 * and every browser print the same characters.
 */
export function formatUtcInstant(value: string, options: UtcInstantOptions = {}): string {
  const parts = INSTANT.exec(value);
  if (!parts) return value;
  const [year, month, day, hour, minute, second] = parts.slice(1, 7).map(Number) as [
    number,
    number,
    number,
    number,
    number,
    number,
  ];
  const calendar = new Date(Date.UTC(year, month - 1, day));
  // Date rolls an invented day into the next month; compare it back to what was written.
  if (
    calendar.getUTCFullYear() !== year ||
    calendar.getUTCMonth() !== month - 1 ||
    calendar.getUTCDate() !== day ||
    hour > 23 ||
    minute > 59 ||
    second > 59
  )
    return value;
  const fraction = (parts[7] ?? "").padEnd(3, "0");
  const parsed = new Date(`${value.slice(0, 19)}.${fraction}${parts[8]}`);
  if (Number.isNaN(parsed.getTime())) return value;
  const { milliseconds = "auto" } = options;
  const showFraction = milliseconds === "always" || (milliseconds === "auto" && fraction !== "000");
  const iso = parsed.toISOString();
  return `${iso.slice(0, 10)} ${iso.slice(11, showFraction ? 23 : 19)} UTC`;
}

/**
 * Reads epoch milliseconds as "YYYY-MM-DD HH:MM:SS UTC", with the same options as
 * formatUtcInstant. A value that is not a real time reads "Unknown time" rather than throwing.
 */
export function formatUtcEpoch(ms: number, options: UtcInstantOptions = {}): string {
  const date = new Date(ms);
  if (!Number.isFinite(ms) || Number.isNaN(date.getTime())) return "Unknown time";
  return formatUtcInstant(date.toISOString(), options);
}

patterns/incident-response/incident-state.ts

import type {
  IncidentActionRequest,
  IncidentActionResult,
  IncidentCase,
  IncidentSnapshot,
} from "./types";

export function prioritizeIncidents(cases: readonly IncidentCase[]): IncidentCase[] {
  return [...cases].sort(
    (a, b) =>
      Number(a.status === "resolved") - Number(b.status === "resolved") ||
      a.priority - b.priority ||
      a.openedAt - b.openedAt,
  );
}

export function validateIncidentText(value: string, label: string): string | undefined {
  if (value.trim().length < 12) return `Add a ${label.toLowerCase()} of at least 12 characters.`;
  if (value.trim().length > 1000) return `${label} must be 1,000 characters or fewer.`;
  return undefined;
}

/** Local reference host. Services must enforce these rules transactionally at their own boundary. */
export function applyIncidentAction(
  snapshot: IncidentSnapshot,
  request: IncidentActionRequest,
  at: number,
): { snapshot: IncidentSnapshot; result: IncidentActionResult } {
  const refuse = (kind: "rejected" | "conflict", message: string) => ({
    snapshot,
    result: { kind, message },
  });
  const current = snapshot.cases.find((item) => item.id === request.caseId);
  if (!current) return refuse("rejected", "This case is no longer available. Select another case.");
  if (current.revision !== request.expectedRevision)
    return refuse(
      "conflict",
      "This case changed while you were working. Review the latest details before retrying.",
    );
  if (!current.permissions[request.action.type])
    return refuse(
      "rejected",
      current.unavailableReason ?? "You do not have permission for this action.",
    );
  if (!Number.isFinite(at) || !Number.isFinite(new Date(at).getTime()) || at < current.updatedAt)
    return refuse(
      "rejected",
      "The action time precedes the latest case update. Refresh the source time.",
    );
  const actor = snapshot.owners.find((owner) => owner.id === snapshot.operatorId);
  if (!actor)
    return refuse(
      "rejected",
      "Your operator identity is unavailable. Reconnect before updating this case.",
    );
  if (current.status === "resolved" && request.action.type !== "note")
    return refuse("rejected", "This case is already resolved. You can still add a handover note.");

  const next = { ...current, revision: current.revision + 1, updatedAt: at };
  const action = request.action;
  let label = "";
  let detail = "";
  switch (action.type) {
    case "acknowledge":
      if (current.status !== "new")
        return refuse("rejected", "This case has already been acknowledged.");
      next.status = "acknowledged";
      next.ownerId = current.ownerId ?? actor.id;
      label = "Case acknowledged";
      detail = `${actor.name} accepted the case for review.`;
      break;
    case "assign": {
      const owner = snapshot.owners.find((item) => item.id === action.ownerId);
      if (!owner)
        return refuse("rejected", "That owner is no longer available. Choose another owner.");
      if (current.ownerId === owner.id)
        return refuse("rejected", "This case is already assigned to that owner.");
      next.ownerId = owner.id;
      label = "Owner assigned";
      detail = `${owner.name} · ${owner.role}`;
      break;
    }
    case "resolve": {
      if (current.status !== "acknowledged")
        return refuse("rejected", "Acknowledge this case before resolving it.");
      const error = validateIncidentText(action.reason, "Resolution reason");
      if (error) return refuse("rejected", error);
      next.status = "resolved";
      next.resolution = action.reason.trim();
      label = "Case resolved";
      detail = next.resolution;
      break;
    }
    case "note": {
      const error = validateIncidentText(action.note, "Handover note");
      if (error) return refuse("rejected", error);
      label = "Handover note";
      detail = action.note.trim();
      break;
    }
  }
  next.history = [
    ...current.history,
    { id: `${current.id}-r${next.revision}`, label, detail, at, actor: actor.name },
  ];
  return {
    snapshot: {
      ...snapshot,
      observedAt: Math.max(snapshot.observedAt, at),
      cases: snapshot.cases.map((item) => (item.id === next.id ? next : item)),
    },
    result: { kind: "accepted", message: `${label}. ${current.id} updated.` },
  };
}

patterns/incident-response/types.ts

import type { OperationalState } from "@operator-ds/react";
import type { OperationalDomain } from "../operational-domain";

export type IncidentStatus = "new" | "acknowledged" | "resolved";
export type IncidentAction =
  | { type: "acknowledge" }
  | { type: "assign"; ownerId: string }
  | { type: "resolve"; reason: string }
  | { type: "note"; note: string };

export interface IncidentCase {
  id: string;
  revision: number;
  title: string;
  summary: string;
  priority: 1 | 2 | 3;
  status: IncidentStatus;
  ownerId: string | null;
  location: string;
  openedAt: number;
  updatedAt: number;
  source: string;
  dataState: OperationalState;
  evidence: readonly { id: string; label: string; value: string; detail: string; at: number }[];
  history: readonly { id: string; label: string; detail: string; at: number; actor: string }[];
  permissions: Record<IncidentAction["type"], boolean>;
  unavailableReason?: string;
  resolution?: string;
}

export interface IncidentSnapshot {
  /** Changes when the application replaces the entire workspace source. */
  id: string;
  domain: OperationalDomain;
  title: string;
  location: string;
  observedAt: number;
  operatorId: string;
  owners: readonly { id: string; name: string; role: string }[];
  cases: readonly IncidentCase[];
}

export interface IncidentActionRequest {
  caseId: string;
  expectedRevision: number;
  action: IncidentAction;
}

export type IncidentActionResult = {
  kind: "accepted" | "rejected" | "conflict";
  message: string;
};

export interface IncidentResponseProps {
  snapshot: IncidentSnapshot;
  selectedId: string | null;
  onSelectedIdChange: (id: string) => void;
  /** Publish the canonical snapshot separately; this view never applies optimistic case changes. */
  onAction?: (request: IncidentActionRequest) => Promise<IncidentActionResult>;
}

patterns/incident-response/demo.tsx

"use client";

import { useRef, useState } from "react";
import type { OperationalDomain } from "../operational-domain";
import { createIncidentSnapshot } from "./fixtures";
import { IncidentResponse } from "./incident-response";
import { applyIncidentAction } from "./incident-state";

export function IncidentResponseDemo({
  initialDomain = "military",
}: {
  /** Internal fixture coverage; the public example always opens the support watch. */
  initialDomain?: OperationalDomain;
}) {
  return (
    <div className="flex w-full min-w-0 flex-col gap-2u">
      <TrainingWorkspace key={initialDomain} domain={initialDomain} />
      <p className="m-0 text-oprt-base text-oprt-text-dim">
        Fictional support cases. Acknowledgments, assignments, handovers, and resolutions are saved
        in this local session.
      </p>
    </div>
  );
}

function TrainingWorkspace({ domain }: { domain: OperationalDomain }) {
  const [snapshot, setSnapshot] = useState(() => createIncidentSnapshot(domain));
  const canonical = useRef(snapshot);
  const [selectedId, setSelectedId] = useState<string | null>(snapshot.cases[0]!.id);
  return (
    <IncidentResponse
      snapshot={snapshot}
      selectedId={selectedId}
      onSelectedIdChange={setSelectedId}
      onAction={async (request) => {
        const next = applyIncidentAction(
          canonical.current,
          request,
          canonical.current.observedAt + 60_000,
        );
        canonical.current = next.snapshot;
        setSnapshot(next.snapshot);
        return next.result;
      }}
    />
  );
}

patterns/incident-response/fixtures.ts

import type { OperationalDomain } from "../operational-domain";
import type { IncidentCase, IncidentSnapshot } from "./types";

const time = (value: string) => Date.parse(`2026-10-02T${value}:00Z`);
type CaseSeed = Pick<
  IncidentCase,
  "id" | "title" | "summary" | "priority" | "status" | "ownerId" | "location" | "source"
> & {
  opened: string;
  evidence: readonly [label: string, value: string, detail: string][];
  report: string;
  update?: string;
  resolution?: string;
  unavailableReason?: string;
};

const military: readonly CaseSeed[] = [
  {
    id: "INC-2041",
    title: "North relay link degraded",
    summary:
      "Intermittent packet loss on the logistics support net. The secondary path is carrying traffic while the watch assigns fault isolation and records recovery checks.",
    priority: 1,
    status: "new",
    ownerId: null,
    location: "North relay · Shelter 03",
    source: "Signal watch · Net 4",
    opened: "08:17",
    report: "Checks CHK-418–CHK-420 exceeded the 5% packet-loss watch threshold.",
    update:
      "Secondary route verified. Assign a technician to the primary relay and record the next link check at 08:50 UTC before considering closure.",
    evidence: [
      [
        "Packet loss",
        "18.4%",
        "CHK-420: 10-minute sample on the primary relay; watch threshold 5%.",
      ],
      [
        "Secondary path",
        "Traffic passing",
        "Relay 02 delivery check passed. This confirms the fallback path only.",
      ],
      [
        "Field report",
        "Power steady",
        "Shelter technician recorded normal supply and no visible cable damage; primary-link fault remains open.",
      ],
    ],
  },
  {
    id: "INC-2038",
    title: "Generator service overdue",
    summary:
      "The west support shelter has exceeded its planned generator service window. Backup supply passed the morning check.",
    priority: 2,
    status: "acknowledged",
    ownerId: "mil-rivera",
    location: "West support · Shelter 01",
    source: "Support maintenance",
    opened: "07:45",
    report: "Service window exceeded by two hours; maintenance lead informed.",
    update:
      "Rivera has the service kit. Confirm the backup transfer and attach the completed service check to this case before resolution.",
    evidence: [
      ["Run time", "252 h", "Planned service interval: 250 hours."],
      ["Backup supply", "Available", "Transfer check recorded at 07:40 UTC."],
    ],
  },
  {
    id: "INC-2040",
    title: "East gate intercom unavailable",
    summary:
      "The gate team cannot reach the support desk through the fixed intercom. The handheld fallback is in use.",
    priority: 2,
    status: "new",
    ownerId: "mil-chen",
    location: "East gate · Post 02",
    source: "Gate support desk",
    opened: "08:12",
    report: "Gate attendant reported no audio on the fixed intercom.",
    update:
      "Gate team confirmed the fallback. Chen is coordinating a fixed-handset test with the support technician.",
    evidence: [
      ["Call test", "No audio", "Two tests returned a connection with no audio."],
      ["Fallback", "Handheld radio", "Gate team confirmed contact on the support channel."],
    ],
  },
  {
    id: "INC-2036",
    title: "Supply manifest awaiting sync",
    summary:
      "Three receiving entries are held locally. The supply clerk has retained the signed delivery sheets.",
    priority: 3,
    status: "acknowledged",
    ownerId: "mil-brooks",
    location: "Supply point · Receiving",
    source: "Logistics desk",
    opened: "07:28",
    report: "Receiving workstation has three pending entries.",
    update:
      "Brooks checked all three signed sheets against the local entries. Keep the originals until the receiving archive confirms each record.",
    evidence: [
      ["Pending entries", "3 records", "Last successful sync: 07:21 UTC."],
      ["Paper record", "Retained", "Signed delivery sheets held by the receiving clerk."],
    ],
  },
  {
    id: "INC-2039",
    title: "Backhaul maintenance in progress",
    summary:
      "The carrier is replacing a failed interface at the support network exchange. Updates are owned by the network operations team.",
    priority: 3,
    status: "acknowledged",
    ownerId: "mil-brooks",
    location: "Support exchange · Rack B",
    source: "Network operations",
    opened: "07:58",
    report: "Carrier maintenance notice received and linked to the support log.",
    update:
      "NET-771 remains with network operations. The next watch should review the carrier update due at 09:00 UTC.",
    unavailableReason: "Network operations owns this case. Your watch has read-only access.",
    evidence: [
      ["Carrier reference", "NET-771", "Next update expected at 09:00 UTC."],
      ["Local route", "Available", "Internal support services remain reachable."],
    ],
  },
  {
    id: "INC-2032",
    title: "Weather station reports restored",
    summary: "The support weather feed is reporting after the local interface was restarted.",
    priority: 3,
    status: "resolved",
    ownerId: "mil-rivera",
    location: "Support yard · Mast 01",
    source: "Support maintenance",
    opened: "06:50",
    report: "Three scheduled reports were missing from the support log.",
    resolution:
      "Interface restarted; three consecutive reports arrived within the expected interval.",
    evidence: [
      ["Latest report", "Received", "The 08:30 UTC observation was delivered."],
      ["Observation period", "Complete", "Three scheduled reports checked by the support desk."],
    ],
  },
];

const industrial: readonly CaseSeed[] = [
  {
    id: "INC-3186",
    title: "Cooling loop pressure falling",
    summary:
      "Discharge pressure on the west cooling loop is below the operating band. The standby pump is available; the line remains under observation.",
    priority: 1,
    status: "new",
    ownerId: null,
    location: "West utilities · Pump P-204",
    source: "Utilities control room",
    opened: "08:17",
    report: "Low discharge pressure persisted across three instrument samples.",
    evidence: [
      ["Discharge pressure", "2.1 bar", "Below the supplied operating band of 2.8–3.4 bar."],
      ["Standby pump", "Available", "P-205 passed its scheduled start check at 07:50 UTC."],
      [
        "Operator round",
        "Seal seepage",
        "Minor seepage noted at P-204. Area isolated for inspection.",
      ],
    ],
  },
  {
    id: "INC-3182",
    title: "Compressor vibration elevated",
    summary:
      "The finishing line compressor has elevated bearing vibration. Maintenance is reviewing the trend with the line supervisor.",
    priority: 2,
    status: "acknowledged",
    ownerId: "ind-patel",
    location: "Finishing line · AC-12",
    source: "Condition monitoring",
    opened: "07:45",
    report: "Bearing vibration crossed the supplied maintenance threshold.",
    evidence: [
      ["Vibration", "5.8 mm/s", "Supplied maintenance threshold: 4.5 mm/s."],
      ["Bearing temperature", "68 °C", "Within the supplied 45–75 °C operating band."],
    ],
  },
  {
    id: "INC-3185",
    title: "Loading dock reader offline",
    summary:
      "The dock 03 badge reader is offline. The logistics team is recording authorized vehicle arrivals at the attended gate.",
    priority: 2,
    status: "new",
    ownerId: "ind-morgan",
    location: "Loading dock · Gate 03",
    source: "Site services desk",
    opened: "08:12",
    report: "The reader stopped reporting at the start of the shift.",
    evidence: [
      ["Last heartbeat", "08:11 UTC", "No response from the reader on the local network."],
      ["Access process", "Attended gate", "Logistics supervisor confirmed the staffed fallback."],
    ],
  },
  {
    id: "INC-3180",
    title: "Batch reports awaiting upload",
    summary:
      "Four completed batch reports are held at the packaging workstation pending a connection to the quality archive.",
    priority: 3,
    status: "acknowledged",
    ownerId: "ind-ellis",
    location: "Packaging · Station 07",
    source: "Quality systems",
    opened: "07:28",
    report: "Packaging workstation reported four pending batch records.",
    evidence: [
      ["Pending reports", "4 batches", "The workstation has retained complete local copies."],
      ["Archive check", "Queued", "Quality coordinator notified at 08:00 UTC."],
    ],
  },
  {
    id: "INC-3183",
    title: "Utility meter service visit",
    summary:
      "The utility provider is inspecting the incoming meter communications interface. The provider owns the service record.",
    priority: 3,
    status: "acknowledged",
    ownerId: "ind-ellis",
    location: "Substation · Meter M-01",
    source: "Utility service desk",
    opened: "07:58",
    report: "Provider service notice received by site operations.",
    unavailableReason: "The utility provider owns this case. Your shift has read-only access.",
    evidence: [
      ["Provider reference", "UTL-409", "Next update expected at 09:00 UTC."],
      ["Local supply", "Available", "No interruption reported by the control room."],
    ],
  },
  {
    id: "INC-3176",
    title: "Tank level indication restored",
    summary:
      "The service water tank indication is available after the instrument terminal was reseated.",
    priority: 3,
    status: "resolved",
    ownerId: "ind-patel",
    location: "Water treatment · Tank T-06",
    source: "Instrumentation team",
    opened: "06:50",
    report: "Level indication was missing from the control room display.",
    resolution: "Terminal reseated; indication matched the local gauge through three checks.",
    evidence: [
      ["Tank level", "72%", "Confirmed against the local gauge at 08:30 UTC."],
      [
        "Observation period",
        "Complete",
        "Three instrument readings checked by the shift operator.",
      ],
    ],
  },
];

/** Camp Alder is the public fixture; the industrial source remains for engine regression checks. */
export function createIncidentSnapshot(domain: OperationalDomain = "military"): IncidentSnapshot {
  const isMilitary = domain === "military";
  const owners = isMilitary
    ? [
        { id: "mil-chen", name: "Lt Maya Chen", role: "Signal watch" },
        { id: "mil-rivera", name: "Sgt Luis Rivera", role: "Support maintenance" },
        { id: "mil-brooks", name: "Cpl Erin Brooks", role: "Logistics desk" },
      ]
    : [
        { id: "ind-morgan", name: "Alex Morgan", role: "Shift operations" },
        { id: "ind-patel", name: "Priya Patel", role: "Mechanical maintenance" },
        { id: "ind-ellis", name: "Sam Ellis", role: "Site services" },
      ];
  return {
    id: `incident-${domain}-training`,
    domain,
    title: isMilitary ? "Camp Alder support watch" : "Plant response",
    location: isMilitary ? "Support incident desk · Morning watch" : "Alder Works · Shift A",
    observedAt: time("08:42"),
    operatorId: owners[0]!.id,
    owners,
    cases: (isMilitary ? military : industrial).map((seed) => ({
      id: seed.id,
      revision: 3,
      title: seed.title,
      summary: seed.summary,
      priority: seed.priority,
      status: seed.status,
      ownerId: seed.ownerId,
      location: seed.location,
      openedAt: time(seed.opened),
      updatedAt: time("08:38"),
      source: seed.source,
      dataState: "current",
      evidence: seed.evidence.map(([label, value, detail], index) => ({
        id: `${seed.id}-e${index}`,
        label,
        value,
        detail,
        at: time(index === 0 ? "08:38" : index === 1 ? "08:36" : "08:31"),
      })),
      history: [
        {
          id: `${seed.id}-h1`,
          label: "Case opened",
          detail: seed.report,
          at: time(seed.opened),
          actor: seed.source,
        },
        {
          id: `${seed.id}-h2`,
          label:
            seed.status === "new"
              ? isMilitary
                ? "Watch update"
                : "Shift update"
              : "Case acknowledged",
          detail:
            seed.status === "new"
              ? `Initial evidence collected. Awaiting ${isMilitary ? "watch" : "shift"} acknowledgment.`
              : "Owner accepted the case and reviewed the available evidence.",
          at: time("08:24"),
          actor: seed.ownerId
            ? owners.find((owner) => owner.id === seed.ownerId)!.name
            : seed.source,
        },
        {
          id: `${seed.id}-h3`,
          label: seed.resolution ? "Case resolved" : "Evidence updated",
          detail: seed.resolution ?? seed.update ?? "Latest field report added to the case.",
          at: time("08:38"),
          actor: seed.source,
        },
      ],
      permissions: {
        acknowledge: !seed.unavailableReason,
        assign: !seed.unavailableReason,
        resolve: !seed.unavailableReason,
        note: !seed.unavailableReason,
      },
      ...(seed.resolution ? { resolution: seed.resolution } : {}),
      ...(seed.unavailableReason ? { unavailableReason: seed.unavailableReason } : {}),
    })),
  };
}