feat(tabs): COD-359 add owner-scoped tab layouts

src/tab-layout-persistence.ts

@@ -0,0 +1,144 @@
+/**
+ * @fileoverview Owner-scoped tab-layout persistence and legacy migration primitives.
+ *
+ * This module is deliberately independent of routes and runtime managers. Callers
+ * provide persisted/live session facts plus saved webviews in server-store order.
+ */
+
+import { normalizeTabLayout, type TabLayout, type TabRef, type TabRefMetadata } from './tab-layout.js';
+
+export const SINGLE_USER_LAYOUT_OWNER = '@single';
+
+export interface TabLayoutSessionRecord {
+  id: string;
+  owner?: string;
+  createdAt: number;
+  parentSessionId?: string;
+}
+
+export interface TabLayoutWebviewRecord {
+  id: string;
+  owner?: string;
+}
+
+export interface TabLayoutMigrationInput {
+  owner: string;
+  layouts?: Readonly<Record<string, TabLayout>>;
+  sessionOrder?: readonly string[];
+  persistedSessions: readonly TabLayoutSessionRecord[];
+  liveSessions: readonly TabLayoutSessionRecord[];
+  /** Saved webviews in authoritative server-store order. */
+  webviews: readonly TabLayoutWebviewRecord[];
+  /** Required only when creating a layout, making migration deterministic in tests. */
+  updatedAt?: string;
+}
+
+export interface TabLayoutMigrationResult {
+  layout: TabLayout;
+  layouts: Record<string, TabLayout>;
+  created: boolean;
+}
+
+/** Resolve the persistence key without accepting an owner key from a client. */
+export function ownerLayoutKey(username?: string): string {
+  return username || SINGLE_USER_LAYOUT_OWNER;
+}
+
+function recordOwner(record: { owner?: string }): string {
+  return record.owner ?? SINGLE_USER_LAYOUT_OWNER;
+}
+
+function compareSessions(a: TabLayoutSessionRecord, b: TabLayoutSessionRecord): number {
+  return a.createdAt - b.createdAt || (a.id < b.id ? -1 : a.id > b.id ? 1 : 0);
+}
+
+function collectSessions(input: TabLayoutMigrationInput): Map<string, TabLayoutSessionRecord> {
+  const sessions = new Map<string, TabLayoutSessionRecord>();
+  for (const record of input.persistedSessions) sessions.set(record.id, { ...record });
+  // A matching live record is authoritative as a whole. In particular, absent
+  // optional owner/parent fields mean single-user ownership and root lineage;
+  // retaining those fields from a stale persisted copy changes their semantics.
+  for (const record of input.liveSessions) sessions.set(record.id, { ...record });
+  return sessions;
+}
+
+function buildMetadata(
+  input: TabLayoutMigrationInput,
+  sessions: ReadonlyMap<string, TabLayoutSessionRecord>
+): TabRefMetadata[] {
+  const ownerSessions = [...sessions.values()]
+    .filter((record) => recordOwner(record) === input.owner)
+    .sort(compareSessions);
+  const sessionOrder = new Map(ownerSessions.map((record, index) => [record.id, index]));
+  const metadata: TabRefMetadata[] = [...sessions.values()].map((record) => ({
+    kind: 'session',
+    id: record.id,
+    ownerValid: recordOwner(record) === input.owner,
+    visible: true,
+    order: sessionOrder.get(record.id) ?? record.createdAt,
+    parentSessionId: record.parentSessionId,
+  }));
+  const webviewOffset = ownerSessions.length;
+  input.webviews.forEach((record, index) => {
+    metadata.push({
+      kind: 'webview',
+      id: record.id,
+      ownerValid: recordOwner(record) === input.owner,
+      visible: true,
+      order: webviewOffset + index,
+    });
+  });
+  return metadata;
+}
+
+/**
+ * Normalize an existing owner layout, or idempotently migrate legacy flat order.
+ * Unknown stored refs remain unknown to metadata and are therefore preserved.
+ * No input object is mutated; validation/capacity failure is atomic.
+ */
+export function normalizeOrMigrateOwnerTabLayout(input: TabLayoutMigrationInput): TabLayoutMigrationResult {
+  const sessions = collectSessions(input);
+  const metadata = buildMetadata(input, sessions);
+  const existing = input.layouts && Object.hasOwn(input.layouts, input.owner) ? input.layouts[input.owner] : undefined;
+  if (existing) {
+    const layout = normalizeTabLayout(existing, metadata);
+    return { layout, layouts: { ...(input.layouts ?? {}), [input.owner]: layout }, created: false };
+  }
+
+  const ownerSessions = [...sessions.values()].filter((record) => recordOwner(record) === input.owner);
+  const ownerSessionById = new Map(ownerSessions.map((record) => [record.id, record]));
+  const liveOwnerIds = new Set(
+    input.liveSessions.filter((record) => recordOwner(record) === input.owner).map((record) => record.id)
+  );
+  const seen = new Set<string>();
+  const orderedSessions: TabLayoutSessionRecord[] = [];
+  for (const id of input.sessionOrder ?? []) {
+    const record = ownerSessionById.get(id);
+    if (!record || seen.has(id)) continue;
+    seen.add(id);
+    orderedSessions.push(record);
+  }
+  for (const record of ownerSessions.filter((item) => !seen.has(item.id)).sort(compareSessions)) {
+    seen.add(record.id);
+    orderedSessions.push(record);
+  }
+
+  const refs: TabRef[] = orderedSessions.map((record) => {
+    const manual = record.parentSessionId !== undefined && liveOwnerIds.has(record.parentSessionId);
+    return manual ? { kind: 'session', id: record.id, placement: 'manual' } : { kind: 'session', id: record.id };
+  });
+  for (const webview of input.webviews) {
+    if (recordOwner(webview) === input.owner) refs.push({ kind: 'webview', id: webview.id });
+  }
+
+  const layout = normalizeTabLayout(
+    {
+      version: 0,
+      groups: [],
+      ungrouped: refs,
+      updatedAt: input.updatedAt ?? new Date().toISOString(),
+    },
+    metadata
+  );
+  return { layout, layouts: { ...(input.layouts ?? {}), [input.owner]: layout }, created: true };
+}