Add support for fusing/unfusing JellyLMS zones into synchronized

multi-room groups, addressed by MAC (derived from the `lms-{mac}` device id).

src/lib/stores/lmsSync.ts

@@ -0,0 +1,133 @@
+/**
+ * LMS multi-room sync ("fuse zones") store.
+ *
+ * The JellyLMS plugin registers each LMS player as a Jellyfin session whose
+ * device id is `lms-{MacAddress}`. We use that prefix both to detect which cast
+ * targets are fuseable LMS zones and to recover the MAC the SyncGroups API needs.
+ *
+ * Fusing model (per product decision): the currently-controlled zone is the sync
+ * master; other selected zones join it. Toggling an already-grouped zone off
+ * decouples just that zone; toggling the master off dissolves the group.
+ *
+ * TRACES: UR-010 | JA-021, JA-025 | DR-037
+ */
+
+import { writable, get } from "svelte/store";
+import { commands } from "$lib/api/bindings";
+import type { Session } from "$lib/api/types";
+import type { LmsSyncGroup } from "$lib/api/bindings";
+
+const LMS_DEVICE_PREFIX = "lms-";
+
+/** Is this cast target an LMS zone (and therefore fuseable)? */
+export function isLmsSession(session: Session | null | undefined): boolean {
+  return !!session?.deviceId?.startsWith(LMS_DEVICE_PREFIX);
+}
+
+/** Recover the LMS player MAC from a session, or null if it isn't an LMS zone. */
+export function macForSession(session: Session | null | undefined): string | null {
+  const deviceId = session?.deviceId;
+  if (!deviceId?.startsWith(LMS_DEVICE_PREFIX)) return null;
+  return deviceId.slice(LMS_DEVICE_PREFIX.length);
+}
+
+interface LmsSyncState {
+  groups: LmsSyncGroup[];
+  isBusy: boolean;
+  error: string | null;
+}
+
+function createLmsSyncStore() {
+  const { subscribe, update, set } = writable<LmsSyncState>({
+    groups: [],
+    isBusy: false,
+    error: null,
+  });
+
+  /** Refresh the list of current sync groups from the server. */
+  async function refresh(): Promise<void> {
+    try {
+      const groups = await commands.lmsGetSyncGroups();
+      update((s) => ({ ...s, groups, error: null }));
+    } catch (error) {
+      // The plugin may not be installed; treat as "no groups" rather than fatal.
+      console.warn("[LmsSync] Failed to load sync groups:", error);
+      update((s) => ({ ...s, groups: [] }));
+    }
+  }
+
+  /** All MACs that are part of any sync group (master or slave). */
+  function groupedMacs(): Set<string> {
+    const macs = new Set<string>();
+    for (const g of get({ subscribe }).groups) {
+      macs.add(g.masterMac);
+      for (const slave of g.slaveMacs ?? []) macs.add(slave);
+    }
+    return macs;
+  }
+
+  /**
+   * Add an LMS zone to the master's sync group (fuse it in).
+   * Preserves any zones already grouped with the master.
+   */
+  async function fuseZone(masterMac: string, zoneMac: string): Promise<void> {
+    if (masterMac === zoneMac) return;
+    update((s) => ({ ...s, isBusy: true, error: null }));
+    try {
+      const existing = get({ subscribe }).groups.find((g) => g.masterMac === masterMac);
+      const slaves = new Set(existing?.slaveMacs ?? []);
+      slaves.add(zoneMac);
+      await commands.lmsCreateSyncGroup(masterMac, [...slaves]);
+      await refresh();
+    } catch (error) {
+      const message = error instanceof Error ? error.message : "Failed to fuse zone";
+      update((s) => ({ ...s, error: message }));
+      throw error;
+    } finally {
+      update((s) => ({ ...s, isBusy: false }));
+    }
+  }
+
+  /**
+   * Remove a single zone from its group. If the zone is a group's master, the
+   * whole group is dissolved (a group can't outlive its master).
+   */
+  async function decoupleZone(zoneMac: string): Promise<void> {
+    update((s) => ({ ...s, isBusy: true, error: null }));
+    try {
+      const asMaster = get({ subscribe }).groups.find((g) => g.masterMac === zoneMac);
+      if (asMaster) {
+        await commands.lmsDissolveSyncGroup(zoneMac);
+      } else {
+        await commands.lmsUnsyncPlayer(zoneMac);
+      }
+      await refresh();
+    } catch (error) {
+      const message = error instanceof Error ? error.message : "Failed to decouple zone";
+      update((s) => ({ ...s, error: message }));
+      throw error;
+    } finally {
+      update((s) => ({ ...s, isBusy: false }));
+    }
+  }
+
+  function clearError(): void {
+    update((s) => ({ ...s, error: null }));
+  }
+
+  function reset(): void {
+    set({ groups: [], isBusy: false, error: null });
+  }
+
+  return {
+    subscribe,
+    refresh,
+    groupedMacs,
+    fuseZone,
+    decoupleZone,
+    clearError,
+    reset,
+  };
+}
+
+export const lmsSync = createLmsSyncStore();