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import type { SurfaceSpec } from "@dispatch/ui-contract";
import type { QueuedMessage } from "@dispatch/wire";
/**
* Pure parser for the `rendererId: "message-queue"` custom-field payload.
*
* The message-queue extension's per-conversation surface emits ONE `custom`
* field with `rendererId: "message-queue"` and `payload: QueuePayload`
* (`{ messages: QueuedMessage[] }` — the current queue snapshot). This parser
* validates the untyped `payload: unknown` at the network seam so a
* hostile/partial payload can never crash the renderer (graceful skip → null).
*
* Empty `messages` is a valid, parseable state (the queue is empty — nothing to
* render); the caller hides the panel. Null is returned only for a malformed
* payload shape.
*/
export interface MessageQueueData {
readonly messages: readonly QueuedMessage[];
}
function isQueuedMessage(v: unknown): v is QueuedMessage {
if (typeof v !== "object" || v === null) return false;
const o = v as Record<string, unknown>;
return (
typeof o.id === "string" &&
typeof o.text === "string" &&
typeof o.queuedAt === "number" &&
Number.isFinite(o.queuedAt)
);
}
export function parseMessageQueuePayload(payload: unknown): MessageQueueData | null {
if (typeof payload !== "object" || payload === null) return null;
const obj = payload as Record<string, unknown>;
const raw = obj.messages;
if (!Array.isArray(raw)) return null;
const messages: QueuedMessage[] = [];
for (const entry of raw) {
if (!isQueuedMessage(entry)) return null;
messages.push(entry);
}
return { messages };
}
/** Queue size from a validated snapshot; absent/malformed data stays unknown. */
export function messageQueueCount(spec: SurfaceSpec | null): number | undefined {
const field = spec?.fields.find(
(field) => field.kind === "custom" && field.rendererId === MESSAGE_QUEUE_RENDERER_ID,
);
if (field?.kind !== "custom") return undefined;
return parseMessageQueuePayload(field.payload)?.messages.length;
}
/** The `rendererId` the message-queue extension's `custom` surface field uses. */
export const MESSAGE_QUEUE_RENDERER_ID = "message-queue";
/**
* Optimistic-removal view-model for the queue list.
*
* The `chat.queue.cancel` op is fire-and-forget + idempotent: success is
* confirmed by the `message-queue` SURFACE updating (the cancelled message
* leaves the snapshot), not by a reply. To avoid a flash of the row lingering
* for a round-trip, the renderer hides a row the instant the user clicks cancel
* (tracking the cancelled id locally), then reconciles when the surface pushes
* the post-cancel snapshot. These two pure helpers drive that — the component
* holds the cancelled-id set as a thin `$state` wrapper and delegates all
* decisions here.
*/
/**
* The messages the renderer should show: the surface snapshot MINUS any
* optimistically-cancelled ids (a cancel whose surface confirmation hasn't
* arrived yet). Pure — no mutation of inputs.
*/
export function selectVisibleMessages(
messages: readonly QueuedMessage[],
cancelledIds: ReadonlySet<string>,
): readonly QueuedMessage[] {
if (cancelledIds.size === 0) return messages;
return messages.filter((m) => !cancelledIds.has(m.id));
}
/**
* Reconcile the cancelled-id set against a NEW surface snapshot: keep only the
* ids that are STILL queued (the cancel is pending — its surface confirmation
* hasn't landed). Drop ids that have left the snapshot: the server confirmed
* the removal (or the message drained as steering / the queue cleared), so the
* optimistic hide is no longer needed. This keeps the set bounded — it never
* outlives the rows it tracks. Pure — returns a NEW set (callers assign it to
* the reactive `$state`).
*/
export function reconcileCancelledIds(
messages: readonly QueuedMessage[],
cancelledIds: ReadonlySet<string>,
): ReadonlySet<string> {
if (cancelledIds.size === 0) return EMPTY_STRING_SET;
const stillQueued = new Set<string>();
for (const m of messages) {
if (cancelledIds.has(m.id)) stillQueued.add(m.id);
}
// Same set back → return the input identity so the component's `$state` setter
// sees no change (avoids a spurious reactive cycle).
if (stillQueued.size === cancelledIds.size) {
let same = true;
for (const id of cancelledIds) {
if (!stillQueued.has(id)) {
same = false;
break;
}
}
if (same) return cancelledIds;
}
return stillQueued;
}
const EMPTY_STRING_SET: ReadonlySet<string> = new Set<string>();
|
