fix: Report and retry media failures for every camera in a grid (#2658)

- Closes: #2637
 - Related: #2099

src/card-controller/issues/factory.ts

@@ -32,7 +32,7 @@ export const createIssueManager = (
   manager.addIssue(new InitializationIssue(api));
   manager.addIssue(new LegacyResourceIssue(changeCallback));
   manager.addIssue(new MediaQueryIssue(api));
-  manager.addIssue(new MediaUnavailableIssue(api, changeCallback));
+  manager.addIssue(new MediaUnavailableIssue(api));
 
   return manager;
 };

src/card-controller/issues/issues/media-unavailable.ts

@@ -1,16 +1,13 @@
 import type { IssueResolveContext, IssueTriggerContext } from 'issue';
 
-import type { ConditionState } from '../../../condition-trigger/conditions/types.js';
 import type {
   Notification,
   NotificationDetail,
 } from '../../../config/schema/actions/types.js';
 import { TROUBLESHOOTING_MEDIA_URL } from '../../../const.js';
 import { localize } from '../../../localize/localize.js';
-import type { UnsubscribeCallback } from '../../../types.js';
-import { Timer } from '../../../utils/timer.js';
+import { getDisplayedTargetIDs } from '../../../view/layout.js';
 import { IMAGE_VIEW_TARGET_ID_SENTINEL } from '../../../view/target-id.js';
-import { isAnyMediaViewName } from '../../../view/view.js';
 import type { CardIssueManagerAPI } from '../../types.js';
 import { createRetryControl } from '../retry-control.js';
 import type { Issue, IssueDescription } from '../types.js';
@@ -40,6 +37,9 @@ declare module 'issue' {
   interface IssueResolveContext {
     media_unavailable: {
       targetID: string;
+
+      // Optionally limits the clearing to one kind of failure.
+      reason?: MediaUnavailableIssueReason;
     };
   }
 }
@@ -50,8 +50,6 @@ interface TargetError {
   description?: string;
 }
 
-export const MEDIA_LOADING_TIMEOUT_SECONDS = 10;
-
 // The per-cause presentation (localization key + icon), shared by the
 // notification metadata and the reconnecting placeholder so each cause is
 // described in exactly one place.
@@ -85,33 +83,20 @@ export const MEDIA_UNAVAILABLE_REASONS: Record<
   },
 };
 
+// Reports media failures for the targets the user can currently see. Failures
+// are raised and cleared by the components observing the media (e.g. providers)
+// -- player errors and stalls via the liveness detectors, and a load that never
+// arrives via each media host's load watchdog. This issue scopes them to the
+// displayed targets and drives the throttled reload that retries them.
 export class MediaUnavailableIssue implements Issue {
   public readonly key = 'media_unavailable' as const;
 
-  private _issueActive = false;
   private _erroredTargets = new Map<string, TargetError>();
 
-  // Timer fires when a target has been loading too long without success.
-  private _timer = new Timer();
-  private _timerTargetID: string | null = null;
-
   private _api: CardIssueManagerAPI;
-  private _onChange: (() => void) | null;
-  private _unsubscribeCallback: UnsubscribeCallback;
 
-  constructor(api: CardIssueManagerAPI, onChange?: () => void) {
+  constructor(api: CardIssueManagerAPI) {
     this._api = api;
-    this._onChange = onChange ?? null;
-
-    // React to a target's media loading; unload / select changes are
-    // irrelevant here.
-    this._unsubscribeCallback = this._api
-      .getMediaLoadedInfoManager()
-      .subscribe((change) => {
-        if (change.type === 'load') {
-          this._onMediaLoad(change.targetID);
-        }
-      });
   }
 
   // =========================================================================
@@ -126,67 +111,29 @@ export class MediaUnavailableIssue implements Issue {
     });
   }
 
-  // A target is proven to be delivering media again. Stronger evidence than a
-  // media load, which only says a player attached, so it clears any recorded
-  // error.
   public resolve(context: IssueResolveContext['media_unavailable']): void {
+    const error = this._erroredTargets.get(context.targetID);
+    if (!error || (context.reason && context.reason !== error.reason)) {
+      return;
+    }
+
     this._erroredTargets.delete(context.targetID);
-    this._cancelPendingTimer(context.targetID);
-  }
-
-  // =========================================================================
-  // Detection -- called by the manager on every state change.
-  // =========================================================================
-
-  public detectDynamic(state: ConditionState): void {
-    if (!isAnyMediaViewName(state.view)) {
-      this._deactivate();
-      return;
-    }
-
-    // A known error for the current target activates immediately, even if its
-    // (frozen) media still reads as loaded (it might be loaded but then
-    // reported a playback error that stops playback but leaves the player
-    // attached). Errors are cleared out-of-band, by `resolve` or by
-    // `_onMediaLoad`.
-    if (this._hasError(state)) {
-      this._activate();
-      return;
-    }
-
-    if (state.mediaLoadedInfo) {
-      // Loaded with no known error: healthy.
-      this._deactivate();
-      return;
-    }
-
-    this._handlePendingLoad(state);
-  }
-
-  // A load proves media attached for the target. That ends any wait on it, and
-  // refutes a `not_loading` error. It is no evidence of recovery for any other
-  // reason, so those clear only via `resolve`.
-  private _onMediaLoad(targetID: string): void {
-    let changed = this._cancelPendingTimer(targetID);
-    if (this._erroredTargets.get(targetID)?.reason === 'not_loading') {
-      this._erroredTargets.delete(targetID);
-      changed = true;
-    }
-    if (changed) {
-      this._onChange?.();
-    }
   }
 
   // =========================================================================
   // State queries -- called by the manager to read current state.
   // =========================================================================
 
+  // Reported exactly when a target on screen has a known failure, even if its
+  // (frozen) media still reads as loaded (it might be loaded but then reported
+  // a playback error that stops playback but leaves the player attached).
+  // Failures are cleared out-of-band, by `resolve`.
   public hasIssue(): boolean {
-    return this._issueActive;
+    return !!this._getDisplayedErrors().size;
   }
 
   public getIssue(): IssueDescription | null {
-    if (!this._issueActive) {
+    if (!this.hasIssue()) {
       return null;
     }
     return {
@@ -197,20 +144,7 @@ export class MediaUnavailableIssue implements Issue {
   }
 
   public getNotification(): Notification {
-    const targets = new Map(this._erroredTargets);
-
-    // The pending-load timer's target is a slow initial load that has not yet
-    // errored. Gate on the timer still running: once it is stopped (a hard error
-    // on another target took over, or the view moved on), _timerTargetID lingers
-    // and would otherwise paint a stale "not loading" line for a target that has
-    // since loaded.
-    if (
-      this._timerTargetID &&
-      this._timer.isRunning() &&
-      !targets.has(this._timerTargetID)
-    ) {
-      targets.set(this._timerTargetID, { reason: 'not_loading' });
-    }
+    const targets = this._getDisplayedErrors();
 
     // The free-text causes go in the context block rather than on the metadata
     // lines, which stay short enough to scan when several cameras fail at once.
@@ -269,20 +203,11 @@ export class MediaUnavailableIssue implements Issue {
   // =========================================================================
 
   public needsRetry(): boolean {
-    return this._issueActive;
+    return this.hasIssue();
   }
 
   public retry(): boolean {
-    // Build the set of targets to retry: all errored targets plus the
-    // target the pending timer is tracking (so a user-initiated retry
-    // works even before the timeout fires). A stopped timer leaves
-    // _timerTargetID behind, so gate on it still running: that target may
-    // since have loaded.
-    const retryTargets = new Set(this._erroredTargets.keys());
-    if (this._timerTargetID && this._timer.isRunning()) {
-      retryTargets.add(this._timerTargetID);
-    }
-
+    const retryTargets = this._getDisplayedErrors();
     if (!retryTargets.size) {
       return false;
     }
@@ -291,16 +216,15 @@ export class MediaUnavailableIssue implements Issue {
     // only way to rebuild a stream from scratch.
     const view = this._api.getViewManager().getView();
     const mediaEpoch = { ...(view?.context?.mediaEpoch ?? {}) };
-    for (const id of retryTargets) {
+    for (const id of retryTargets.keys()) {
       mediaEpoch[id] = (mediaEpoch[id] ?? 0) + 1;
     }
 
-    // Intentionally keep _issueActive, _erroredTargets, and the pending
-    // timer in place. The issue stays visible while the provider re-attempts
-    // loading underneath. If the retry succeeds, the fresh load clears a
-    // not-loading error and the rebuilt provider's liveness observation
-    // resolves a stream error. If it fails silently (e.g. bogus stream name),
-    // the error stays visible immediately -- no new 10s grace period.
+    // Intentionally keep _erroredTargets in place. The issue stays visible
+    // while the provider re-attempts loading underneath. If the retry succeeds,
+    // the fresh load clears a not-loading error and the rebuilt provider's
+    // liveness observation resolves a stream error. If it fails silently (e.g.
+    // bogus stream name), the error stays visible immediately.
     this._api.getViewManager().setViewWithMergedContext({ mediaEpoch });
     return false;
   }
@@ -310,83 +234,27 @@ export class MediaUnavailableIssue implements Issue {
   // =========================================================================
 
   public reset(): void {
-    this._deactivate();
     this._erroredTargets.clear();
   }
 
-  // Stop reacting to media loads at end of life.
-  public destroy(): void {
-    this._unsubscribeCallback();
-  }
-
-  // Stop the pending-load timer so offscreen time doesn't count toward the
-  // 10s threshold. Preserve _issueActive, _erroredTargets, and
-  // _timerTargetID: already-visible errors remain visible on reattach, and
-  // retaining _timerTargetID lets the existing active/target-mismatch guard
-  // in _handlePendingLoad avoid spuriously deactivating the preserved
-  // issue when the same target is still loading on resume. The timer is
-  // re-armed with a fresh window by the next detectDynamic pass.
-  public suspend(): void {
-    this._timer.stop();
-  }
-
   // =========================================================================
   // Private helpers.
   // =========================================================================
 
-  // Stop waiting on a target's load, if it is the one being waited on. Returns
-  // whether it was.
-  private _cancelPendingTimer(targetID: string): boolean {
-    if (this._timerTargetID !== targetID) {
-      return false;
-    }
-    this._timer.stop();
-    this._timerTargetID = null;
-    return true;
+  // The errored targets the user can currently see. An error recorded for a
+  // target that has since left the screen names something they cannot look at,
+  // and reloading it would achieve nothing. Read fresh rather than remembered:
+  // a change in conditions can re-evaluate an override that replaces the
+  // configured cameras, leaving the view exactly as it was.
+  private _getDisplayedErrors(): Map<string, TargetError> {
+    const view = this._api.getViewManager().getView();
+    if (!view) {
+      return new Map();
     }
 
-  // Media not yet loaded and no known error: start (or keep) a timeout to catch
-  // a slow or failed initial load. No targetID means no provider is rendering
-  // media (e.g. the viewer shows "No media to display"), so there's nothing to
-  // wait for.
-  private _handlePendingLoad(state: ConditionState): void {
-    if (!state.targetID) {
-      this._deactivate();
-      return;
-    }
-
-    const targetID = state.targetID;
-
-    // When the target changes, clear the active state so the new target gets
-    // its own timeout window instead of inheriting the previous target's.
-    if (this._issueActive && this._timerTargetID !== targetID) {
-      this._deactivate();
-    }
-
-    // Start (or restart) the timer for this target.
-    if (!this._timer.isRunning() || this._timerTargetID !== targetID) {
-      this._timerTargetID = targetID;
-      this._timer.start(MEDIA_LOADING_TIMEOUT_SECONDS, () => {
-        // Record the error on timeout so retry() knows which epoch to bump.
-        this.trigger({ targetID, reason: 'not_loading' });
-        this._activate();
-        this._onChange?.();
-      });
-    }
-  }
-
-  private _hasError(state: ConditionState): boolean {
-    return !!state.targetID && this._erroredTargets.has(state.targetID);
-  }
-
-  private _activate(): void {
-    this._timer.stop();
-    this._issueActive = true;
-  }
-
-  private _deactivate(): void {
-    this._timer.stop();
-    this._timerTargetID = null;
-    this._issueActive = false;
+    const displayedTargetIDs = getDisplayedTargetIDs(view, this._api.getCameraManager());
+    return new Map(
+      [...this._erroredTargets].filter(([targetID]) => displayedTargetIDs.has(targetID)),
+    );
   }
 }

src/components-lib/media-load-watchdog-controller.ts

@@ -0,0 +1,219 @@
+import type { ReactiveController, ReactiveControllerHost } from 'lit';
+
+import type {
+  IssueResolveEventData,
+  IssueTriggerEventData,
+} from '../card-controller/issues/types';
+import type { MediaLoadedInfoEventDetail } from '../types';
+import { onAbort } from '../utils/abort-signal';
+import { Generation } from '../utils/concurrency/generation';
+import { fireAdvancedCameraCardEvent } from '../utils/fire-advanced-camera-card-event';
+import { Timer } from '../utils/timer';
+
+const MEDIA_LOADED_EVENT = 'advanced-camera-card:media:loaded';
+
+export const MEDIA_LOADING_TIMEOUT_SECONDS = 10;
+
+interface MediaLoadWatchdogConfig {
+  getTargetID: () => string | null;
+
+  // Whether the host is currently trying to load media. False when loading is
+  // held back (e.g. lazy loading), or when the host is showing a failure of its
+  // own rather than waiting for media.
+  isLoadExpected: () => boolean;
+
+  // Changes when the media underneath is rebuilt without the host itself being
+  // rebuilt (e.g. a retry re-keying a player below it), so the wait starts
+  // again. Omitted by a host that a retry replaces outright.
+  getAttemptID?: () => unknown;
+}
+
+/**
+ * Watches a media host's load: when the host expects media but none arrives
+ * within the window, raises a `media_unavailable` issue with reason
+ * `not_loading`, and clears it again once media does arrive.
+ *
+ * Loads are observed from the host's own bubble path, so a `media:loaded`
+ * dispatched by any descendant player ends the wait, and that media going away
+ * (its event's abort signal) restarts it if a load is still expected.
+ *
+ * A host may be reused for a succession of targets (a viewer slide swiped from
+ * one media item to the next), so everything learned is scoped to the target it
+ * was learned about. A target change starts a fresh wait and resolves any
+ * failure reported for the target left behind.
+ */
+export class MediaLoadWatchdogController implements ReactiveController {
+  private _host: ReactiveControllerHost & HTMLElement;
+  private _config: MediaLoadWatchdogConfig;
+
+  private _timer = new Timer();
+
+  // What the state below describes: the target, and which attempt at loading it
+  // (see `getAttemptID`). A change in either means everything known is about
+  // media the host has moved on from.
+  private _targetID: string | null = null;
+  private _attemptID: unknown = undefined;
+
+  private _mediaLoaded = false;
+
+  // Identifies which load `_mediaLoaded` describes. One player can replace
+  // another for the same target before the first has gone away, and the first
+  // going away must not be read as the current media being lost.
+  private _loadGeneration = new Generation();
+
+  // Whether the timeout has fired for the current attempt, so a hung load is
+  // reported only once. A retry is a new attempt and is waited on afresh.
+  private _fired = false;
+
+  // The target this watchdog has an outstanding failure reported for, so that
+  // failure can be resolved if the host moves on to another target. It
+  // outlives the attempt that reported it, which keeps the failure on screen
+  // while a retry runs underneath.
+  private _reportedTargetID: string | null = null;
+
+  // Media loads, and the media going away, are observed through listeners and
+  // abort signals that can outlive a disconnect, and a detached host must not be
+  // waited on.
+  private _connected = false;
+
+  constructor(
+    host: ReactiveControllerHost & HTMLElement,
+    config: MediaLoadWatchdogConfig,
+  ) {
+    this._host = host;
+    this._config = config;
+    host.addController(this);
+  }
+
+  public hostConnected(): void {
+    this._connected = true;
+    this._host.addEventListener(MEDIA_LOADED_EVENT, this._onMediaLoaded);
+    this._evaluate();
+  }
+
+  public hostDisconnected(): void {
+    this._connected = false;
+    this._host.removeEventListener(MEDIA_LOADED_EVENT, this._onMediaLoaded);
+    this._timer.stop();
+  }
+
+  public hostUpdated(): void {
+    this._evaluate();
+  }
+
+  private _forgetLoad(): void {
+    this._mediaLoaded = false;
+    this._fired = false;
+    this._loadGeneration.invalidate();
+    this._timer.stop();
+  }
+
+  private _onMediaLoaded = (ev: CustomEvent<MediaLoadedInfoEventDetail>): void => {
+    const targetID = ev.detail.info.targetID;
+
+    // The host's own target is read fresh so a load arriving as the host
+    // switches is attributed to whichever target it actually describes.
+    if (!targetID || targetID !== this._config.getTargetID()) {
+      return;
+    }
+
+    // This load replaces whatever was being followed, which may be a different
+    // target the host has just moved off.
+    this._syncAttempt();
+    this._forgetLoad();
+
+    this._mediaLoaded = true;
+    const generation = this._loadGeneration.next();
+
+    // Media arriving disproves a not-loading failure whoever reported it.
+    this._resolveFailure(targetID);
+
+    // Media going away is not itself a failure, but a load that is still
+    // expected afterwards needs a fresh wait. This is recorded whether or not
+    // the host is attached, since a detached host has no media either.
+    onAbort(ev.detail.signal, () => {
+      if (targetID !== this._targetID || !this._loadGeneration.isCurrent(generation)) {
+        return;
+      }
+
+      this._mediaLoaded = false;
+      this._evaluate();
+    });
+  };
+
+  // Clear a target's not-loading failure, whichever component reported it.
+  // Naming the reason leaves a failure reported for any other reason alone.
+  private _resolveFailure(targetID: string): void {
+    if (this._reportedTargetID === targetID) {
+      this._reportedTargetID = null;
+    }
+
+    fireAdvancedCameraCardEvent<IssueResolveEventData>(this._host, 'issue:resolve', {
+      key: 'media_unavailable',
+      targetID,
+      reason: 'not_loading',
+    });
+  }
+
+  // Discard everything learned about a previous target, or a previous attempt
+  // at the same one.
+  private _syncAttempt(): void {
+    const targetID = this._config.getTargetID();
+    const attemptID = this._config.getAttemptID?.();
+    if (targetID === this._targetID && attemptID === this._attemptID) {
+      return;
+    }
+
+    // If an abandoned target was previously reported, resolve it so it's not
+    // stuck forever
+    if (this._reportedTargetID && this._reportedTargetID !== targetID) {
+      this._resolveFailure(this._reportedTargetID);
+    }
+
+    this._targetID = targetID;
+    this._attemptID = attemptID;
+    this._forgetLoad();
+  }
+
+  private _evaluate(): void {
+    if (!this._connected) {
+      return;
+    }
+
+    this._syncAttempt();
+
+    if (!this._targetID || this._mediaLoaded || !this._config.isLoadExpected()) {
+      this._fired = false;
+      this._timer.stop();
+      return;
+    }
+
+    if (!this._fired && !this._timer.isRunning()) {
+      this._timer.start(MEDIA_LOADING_TIMEOUT_SECONDS, () => this._onTimeout());
+    }
+  }
+
+  private _onTimeout(): void {
+    const targetID = this._targetID;
+
+    // Conditions may have changed while the timer matured.
+    if (
+      !this._connected ||
+      !targetID ||
+      targetID !== this._config.getTargetID() ||
+      this._attemptID !== this._config.getAttemptID?.() ||
+      this._mediaLoaded ||
+      !this._config.isLoadExpected()
+    ) {
+      return;
+    }
+
+    this._fired = true;
+    this._reportedTargetID = targetID;
+    fireAdvancedCameraCardEvent<IssueTriggerEventData>(this._host, 'issue:trigger', {
+      key: 'media_unavailable',
+      targetID,
+      reason: 'not_loading',
+    });
+  }
+}

src/components/image-updating-player.ts

@@ -126,6 +126,13 @@ export class AdvancedCameraCardImageUpdatingPlayer
 
   private _refImage: Ref<HTMLImageElement> = createRef();
 
+  // Whether the <img> currently holds the stock image swapped in by
+  // `_forceSafeImage` rather than the intended media. The safe image load must
+  // not be announced as real media arriving, which may otherwise report a
+  // broken camera as healthy. Cleared on the next render, which restores the
+  // real source.
+  private _showingSafeImage = false;
+
   private _cachedValueController = new CachedValueController(
     this,
     () => this._getEffectiveRefreshSeconds(),
@@ -234,6 +241,10 @@ export class AdvancedCameraCardImageUpdatingPlayer
    * @param _changedProps The changed properties
    */
   protected willUpdate(changedProps: PropertyValues): void {
+    // The render (below) restores the real source (via `live()`), so its load
+    // is the real media again.
+    this._showingSafeImage = false;
+
     const relevantEntity = this._getRelevantEntityForMode(
       resolveImageMode({
         imageConfig: this.imageConfig,
@@ -454,6 +465,7 @@ export class AdvancedCameraCardImageUpdatingPlayer
    */
   private _forceSafeImage(stockOnly?: boolean): void {
     if (this._refImage.value) {
+      this._showingSafeImage = true;
       // Avoid restoring the raw configured URL when proxying is enabled, since
       // that would bypass the proxied/signed URL path on visibility changes.
       const configuredURL =
@@ -495,6 +507,10 @@ export class AdvancedCameraCardImageUpdatingPlayer
             ${ref(this._refImage)}
             src=${live(src)}
             @load=${(ev: Event) => {
+              if (this._showingSafeImage) {
+                return;
+              }
+
               const mediaLoadedInfo = createMediaLoadedInfo(ev, {
                 mediaPlayerController: this._mediaPlayerController,
                 capabilities: {

src/components/image.ts

@@ -12,6 +12,7 @@ import { createRef, ref, type Ref } from 'lit/directives/ref.js';
 
 import type { CameraManager } from '../camera-manager/manager';
 import type { ViewManagerEpoch } from '../card-controller/view/types';
+import { MediaLoadWatchdogController } from '../components-lib/media-load-watchdog-controller';
 import type { ZoomSettingsObserved } from '../components-lib/zoom/types';
 import { handleZoomSettingsObservedEvent } from '../components-lib/zoom/zoom-view-context';
 import type { CameraConfig } from '../config/schema/cameras';
@@ -59,6 +60,40 @@ export class AdvancedCameraCardImage extends LitElement implements MediaPlayer {
 
   private _refImage: Ref<MediaPlayerElement> = createRef();
 
+  constructor() {
+    super();
+
+    // No lazy loading: Reports the image as a media_unavailable issue if it
+    // never arrives.
+    new MediaLoadWatchdogController(this, {
+      getTargetID: () => IMAGE_VIEW_TARGET_ID_SENTINEL,
+      isLoadExpected: () =>
+        // A misconfigured image already shows why nothing can be drawn, and
+        // reloading it cannot change the configuration.
+        !!this.hass && !this._getConfigurationError(),
+
+      // Player is keyed on epoch.
+      getAttemptID: () => this._getMediaEpoch(),
+    });
+  }
+
+  private _getMediaEpoch(): number {
+    const view = this.viewManagerEpoch?.manager.getView();
+    return view?.context?.mediaEpoch?.[IMAGE_VIEW_TARGET_ID_SENTINEL] ?? 0;
+  }
+
+  // Returns the reason no image can be shown at all, or null when one can.
+  // `camera` mode has nothing to draw from without a camera.
+  private _getConfigurationError(): string | null {
+    const mode = resolveImageMode({
+      imageConfig: this.imageConfig,
+      cameraConfig: this.cameraConfig,
+    });
+    return mode === 'camera' && !this.cameraConfig
+      ? localize('error.no_camera_for_image')
+      : null;
+  }
+
   public async getMediaPlayerController(): Promise<MediaPlayerController | null> {
     await this.updateComplete;
     return (await this._refImage.value?.getMediaPlayerController()) ?? null;
@@ -118,24 +153,18 @@ export class AdvancedCameraCardImage extends LitElement implements MediaPlayer {
       return;
     }
 
-    // Determine if this image mode requires a camera
-    const mode = resolveImageMode({
-      imageConfig: this.imageConfig,
-      cameraConfig: this.cameraConfig,
-    });
-
-    if (mode === 'camera' && !this.cameraConfig) {
-      return renderNotificationBlockFromText(localize('error.no_camera_for_image'), {
+    const configurationError = this._getConfigurationError();
+    if (configurationError) {
+      return renderNotificationBlockFromText(configurationError, {
         icon: 'mdi:camera-off',
       });
     }
 
     const view = this.viewManagerEpoch?.manager.getView();
-    const mediaEpoch = view?.context?.mediaEpoch?.[IMAGE_VIEW_TARGET_ID_SENTINEL] ?? 0;
 
     return this._renderContainer(html`
       ${keyed(
-        mediaEpoch,
+        this._getMediaEpoch(),
         html`
           <advanced-camera-card-image-updating-player
             ${ref(this._refImage)}

src/components/live/grid.ts

@@ -20,6 +20,7 @@ import type { CardWideConfig } from '../../config/schema/types.js';
 import type { HomeAssistant } from '../../ha/types.js';
 import liveGridStyle from '../../scss/live-grid.scss?inline';
 import { contentsChanged } from '../../utils/basic.js';
+import { getLiveGridCameraIDs } from '../../view/layout.js';
 
 import './carousel.js';
 
@@ -97,26 +98,22 @@ export class AdvancedCameraCardLiveGrid extends LitElement {
     });
   }
 
-  private _needsGrid(): boolean {
-    const cameraIDs = this.cameraManager?.getStore().getCameraIDsWithCapability('live');
+  private _getGridCameraIDs(): Set<string> | null {
     const view = this.viewManagerEpoch?.manager.getView();
-    return (
-      !!view?.isGrid() &&
-      !!view?.supportsMultipleDisplayModes() &&
-      !!cameraIDs &&
-      cameraIDs.size > 1
-    );
+    return view && this.cameraManager
+      ? getLiveGridCameraIDs(view, this.cameraManager)
+      : null;
   }
 
   protected willUpdate(changedProps: PropertyValues): void {
-    if (changedProps.has('viewManagerEpoch') && this._needsGrid()) {
+    if (changedProps.has('viewManagerEpoch') && this._getGridCameraIDs()) {
       void import('../media-grid.js');
     }
   }
 
   protected render(): TemplateResult | void {
-    const cameraIDs = this.cameraManager?.getStore().getCameraIDsWithCapability('live');
-    if (!cameraIDs?.size || !this._needsGrid()) {
+    const cameraIDs = this._getGridCameraIDs();
+    if (!cameraIDs) {
       return this._renderCarousel();
     }
 

src/components/live/provider.ts

@@ -17,6 +17,7 @@ import { MEDIA_UNAVAILABLE_REASONS } from '../../card-controller/issues/issues/m
 import { LazyLoadController } from '../../components-lib/lazy-load-controller.js';
 import { isAudioIntendedOnLoad } from '../../components-lib/live/audio-intent.js';
 import { StreamLivenessController } from '../../components-lib/live/liveness/stream-liveness-controller.js';
+import { MediaLoadWatchdogController } from '../../components-lib/media-load-watchdog-controller.js';
 import { MediaLoadedInfoSinkController } from '../../components-lib/media-loaded-info-sink-controller.js';
 import type { PartialZoomSettings } from '../../components-lib/zoom/types.js';
 import type { LiveConfig } from '../../config/schema/live.js';
@@ -110,6 +111,24 @@ export class AdvancedCameraCardLiveProvider extends LitElement implements MediaP
 
   private _lazyLoadController: LazyLoadController = new LazyLoadController(this);
 
+  constructor() {
+    super();
+
+    // Watch for media that fails to load. The constructor registers it as a
+    // controller on this host.
+    new MediaLoadWatchdogController(this, {
+      getTargetID: () => this.targetID ?? null,
+      isLoadExpected: () =>
+        this._shouldLoad() &&
+        // Don't report media unavailable for configuration errors as retries
+        // cannot possible help, and a message is already rendered.
+        !this._getConfigurationError() &&
+        // Specific > generic: Don't replace existing failures flagged with
+        // liveness detectors.
+        !this._streamLivenessController.getFailure(),
+    });
+  }
+
   // A note on dynamic imports:
   //
   // We gather the dynamic live provider import promises and do not consider the
@@ -181,6 +200,33 @@ export class AdvancedCameraCardLiveProvider extends LitElement implements MediaP
     }
   }
 
+  // Whether this provider should be loading media at all.
+  private _shouldLoad(): boolean {
+    return this._lazyLoadController.isLoaded();
+  }
+
+  // Returns the reason this camera cannot stream at all, or null when it can.
+  private _getConfigurationError(): string | null {
+    const cameraConfig = this.camera?.getConfig();
+    const provider = getResolvedLiveProvider(cameraConfig);
+
+    if (
+      provider !== 'ha' &&
+      provider !== 'image' &&
+      !(cameraConfig?.camera_entity && cameraConfig.always_error_if_entity_unavailable)
+    ) {
+      return null;
+    }
+
+    if (!cameraConfig?.camera_entity) {
+      return localize('error.no_live_camera');
+    }
+    if (!this.hass?.states[cameraConfig.camera_entity]) {
+      return localize('error.live_camera_not_found');
+    }
+    return null;
+  }
+
   override async getUpdateComplete(): Promise<boolean> {
     // See 'A note on dynamic imports' above for explanation of why this is
     // necessary.
@@ -234,7 +280,7 @@ export class AdvancedCameraCardLiveProvider extends LitElement implements MediaP
   protected render(): TemplateResult | void {
     const cameraConfig = this.camera?.getConfig();
     if (
-      !this._lazyLoadController?.isLoaded() ||
+      !this._shouldLoad() ||
       !this.hass ||
       !this.liveConfig ||
       !this.camera ||
@@ -262,32 +308,15 @@ export class AdvancedCameraCardLiveProvider extends LitElement implements MediaP
 
     const provider = getResolvedLiveProvider(this.camera?.getConfig());
 
-    // `ha`/`image` cannot stream without a camera entity, so validate that
-    // here. Entity *availability* (including the always_error immediate path)
-    // is owned by the liveness controller's EntityAvailabilityDetector and
-    // surfaces via getFailure() below, for all providers.
-    if (
-      provider === 'ha' ||
-      provider === 'image' ||
-      (cameraConfig?.camera_entity && cameraConfig.always_error_if_entity_unavailable)
-    ) {
-      if (!cameraConfig?.camera_entity) {
+    const configurationError = this._getConfigurationError();
+    if (configurationError) {
       return renderMediaNotification({
         icon: 'mdi:camera',
         title: localize('error.configuration_error'),
-          detail: localize('error.no_live_camera'),
+        detail: configurationError,
         targetTitle: this.cameraTitle,
       });
     }
-      if (!this.hass.states[cameraConfig.camera_entity]) {
-        return renderMediaNotification({
-          icon: 'mdi:camera',
-          title: localize('error.configuration_error'),
-          detail: localize('error.live_camera_not_found'),
-          targetTitle: this.cameraTitle,
-        });
-      }
-    }
 
     const failure = this._streamLivenessController.getFailure();
 

src/components/viewer/grid.ts

@@ -17,6 +17,7 @@ import type { CardWideConfig } from '../../config/schema/types.js';
 import type { ViewerConfig } from '../../config/schema/viewer.js';
 import type { ResolvedMediaCache } from '../../ha/resolved-media.js';
 import type { HomeAssistant } from '../../ha/types.js';
+import { getViewerGridCameraIDs } from '../../view/layout.js';
 
 import '../../patches/ha-hls-player.js';
 
@@ -75,19 +76,14 @@ export class AdvancedCameraCardViewerGrid extends LitElement {
   }
 
   protected willUpdate(changedProps: PropertyValues): void {
-    if (changedProps.has('viewManagerEpoch') && this._needsGrid()) {
+    if (changedProps.has('viewManagerEpoch') && this._getGridCameraIDs()) {
       void import('../media-grid.js');
     }
   }
 
-  private _needsGrid(): boolean {
+  private _getGridCameraIDs(): Set<string> | null {
     const view = this.viewManagerEpoch?.manager.getView();
-    const cameraIDs = view?.queryResults?.getCameraIDs();
-    return (
-      !!view?.isGrid() &&
-      !!view?.supportsMultipleDisplayModes() &&
-      (cameraIDs?.size ?? 0) > 1
-    );
+    return view ? getViewerGridCameraIDs(view) : null;
   }
 
   private _gridSelectCamera(cameraID: string): void {
@@ -103,15 +99,14 @@ export class AdvancedCameraCardViewerGrid extends LitElement {
   }
 
   protected render(): TemplateResult {
-    const view = this.viewManagerEpoch?.manager.getView();
-    const cameraIDs = view?.queryResults?.getCameraIDs();
-    if (!cameraIDs || !this._needsGrid()) {
+    const cameraIDs = this._getGridCameraIDs();
+    if (!cameraIDs) {
       return this._renderCarousel();
     }
 
     return html`
       <advanced-camera-card-media-grid
-        .selected=${view?.camera}
+        .selected=${this.viewManagerEpoch?.manager.getView()?.camera}
         .displayConfig=${this.viewerConfig?.display}
         @advanced-camera-card:media-grid:selected=${(
           ev: CustomEvent<MediaGridSelected>,

src/components/viewer/provider.ts

@@ -14,6 +14,7 @@ import type { CameraManager } from '../../camera-manager/manager.js';
 import { QueryType } from '../../camera-manager/types.js';
 import type { ViewManagerEpoch } from '../../card-controller/view/types.js';
 import { LazyLoadController } from '../../components-lib/lazy-load-controller.js';
+import { MediaLoadWatchdogController } from '../../components-lib/media-load-watchdog-controller.js';
 import {
   getSignedURLErrorText,
   SignedURLController,
@@ -36,6 +37,7 @@ import type {
   MediaPlayerController,
   MediaPlayerElement,
 } from '../../types.js';
+import { Generation } from '../../utils/concurrency/generation.js';
 import { classifyMimeType } from '../../utils/mime-type.js';
 import { ViewItemClassifier } from '../../view/item-classifier.js';
 import type { ViewMedia } from '../../view/item.js';
@@ -77,6 +79,9 @@ export class AdvancedCameraCardViewerProvider extends LitElement implements Medi
 
   private _resolvedMedia: ResolvedMedia | null = null;
 
+  // Drops a slow resolution for media the provider has since moved off.
+  private _resolveGeneration = new Generation();
+
   private _signedURLController = new SignedURLController(this, () => {
     if (!this.hass || !this._resolvedMedia) {
       return {};
@@ -99,6 +104,12 @@ export class AdvancedCameraCardViewerProvider extends LitElement implements Medi
   constructor() {
     super();
     this._lazyLoadController.addListener((loaded) => loaded && this._resolveURL());
+
+    // Watch for media load failure (including resolving media ID and signing).
+    new MediaLoadWatchdogController(this, {
+      getTargetID: () => this.media?.getID() ?? null,
+      isLoadExpected: () => this._shouldLoad(),
+    });
   }
 
   public async getMediaPlayerController(): Promise<MediaPlayerController | null> {
@@ -140,19 +151,28 @@ export class AdvancedCameraCardViewerProvider extends LitElement implements Medi
 
   private async _resolveURL(): Promise<void> {
     const contentID = this.media?.getContentID();
-    if (!contentID || !this.hass || !this._lazyLoadController?.isLoaded()) {
+    if (!contentID || !this.hass || !this._shouldLoad()) {
+      this._resolveGeneration.invalidate();
       this._resolvedMedia = null;
       return;
     }
 
+    const generation = this._resolveGeneration.next();
+
     // Clear immediately so the SignedURLController doesn't see a stale URL
     // from the previous media item during the async gap.
     this._resolvedMedia = null;
 
-    this._resolvedMedia =
+    const resolved =
       this.resolvedMediaCache?.get(contentID) ??
       (await resolveMedia(this.hass, contentID, this.resolvedMediaCache)) ??
       null;
+
+    if (!this._resolveGeneration.isCurrent(generation)) {
+      return;
+    }
+
+    this._resolvedMedia = resolved;
     this.requestUpdate();
   }
 
@@ -177,6 +197,10 @@ export class AdvancedCameraCardViewerProvider extends LitElement implements Medi
     }
   }
 
+  private _shouldLoad(): boolean {
+    return this._lazyLoadController.isLoaded();
+  }
+
   private _getRelevantCameraConfig(): CameraConfig | null {
     const cameraID = this.media?.getCameraID();
     return cameraID
@@ -233,12 +257,7 @@ export class AdvancedCameraCardViewerProvider extends LitElement implements Medi
   }
 
   protected render(): TemplateResult | void {
-    if (
-      !this._lazyLoadController?.isLoaded() ||
-      !this.media ||
-      !this.hass ||
-      !this.viewerConfig
-    ) {
+    if (!this._shouldLoad() || !this.media || !this.hass || !this.viewerConfig) {
       return;
     }
 

src/condition-trigger/conditions/types.ts

@@ -41,7 +41,7 @@ export interface ConditionState {
 
   // Generic media target identifier. See @view/target-id for details.
   targetID?: string;
-  triggered?: Set<string>;
+  triggered?: ReadonlySet<string>;
   userAgent?: string;
   view?: AdvancedCameraCardView;
 }

src/scss/media-grid.scss

@@ -37,12 +37,18 @@
   // not change in size (even border-box sizing appears to allow size to change
   // when the element has a non-fixed height).
   border: var(--advanced-camera-card-grid-border-size) solid transparent;
+
+  // Unselected cells cannot be usefully scrolled, so ensure notifications do
+  // not show scrollbars.
+  --advanced-camera-card-notification-block-overflow-y: hidden;
 }
 
 ::slotted([selected]) {
   border: var(--advanced-camera-card-grid-border-size) solid
     var(--advanced-camera-card-grid-selected-border-color);
 
+  --advanced-camera-card-notification-block-overflow-y: auto;
+
   // Selected width = columns × selection factor, capped at 100%.
   width: min(
     100%,

src/scss/notification-block.scss

@@ -29,7 +29,9 @@
   padding: 24px;
   max-width: min(92%, 500px);
   max-height: 100%;
-  overflow-y: auto;
+
+  // A container that cannot usefully be scrolled can set this to 'hidden'.
+  overflow-y: var(--advanced-camera-card-notification-block-overflow-y, auto);
   scrollbar-width: thin;
   text-align: center;
 }

src/view/layout.ts

@@ -0,0 +1,85 @@
+import type { CameraManager } from '../camera-manager/manager';
+import { getViewTargetID } from './target-id';
+import type { View } from './view';
+
+const isGridLayout = (view: View): boolean =>
+  // This reflects whether the view 'asks' for a grid. This is inherited as
+  // the user changes view.
+  view.isGrid() &&
+  // This reflects whether the current view actually *supports* a grid.
+  view.supportsMultipleDisplayModes();
+
+// The cameras a live grid lays out, one cell each, or null when live is laid
+// out as a single carousel instead (incl. when there's <= 1 camera).
+export const getLiveGridCameraIDs = (
+  view: View,
+  cameraManager: CameraManager,
+): Set<string> | null => {
+  if (!isGridLayout(view)) {
+    return null;
+  }
+
+  const cameraIDs = cameraManager.getStore().getCameraIDsWithCapability('live');
+  return cameraIDs.size > 1 ? cameraIDs : null;
+};
+
+// The cameras a viewer grid lays out, one cell each, or null when the viewer is
+// laid out as a single carousel instead (incl. when there's <= 1 camera). The
+// cameras come from the query results, so only a camera with media to show gets
+// a cell.
+export const getViewerGridCameraIDs = (view: View): Set<string> | null => {
+  if (!isGridLayout(view)) {
+    return null;
+  }
+
+  const cameraIDs = view.queryResults?.getCameraIDs();
+  return cameraIDs && cameraIDs.size > 1 ? cameraIDs : null;
+};
+
+// The target shown in each cell of a grid, or null when the view is not laid
+// out as a grid.
+const getGridTargetIDs = (
+  view: View,
+  cameraManager: CameraManager,
+): Set<string> | null => {
+  if (view.is('live')) {
+    // A live cell shows its camera, so the camera is the target.
+    return getLiveGridCameraIDs(view, cameraManager);
+  }
+
+  if (view.isViewerView()) {
+    const cameraIDs = getViewerGridCameraIDs(view);
+    if (!cameraIDs) {
+      return null;
+    }
+
+    // A viewer cell shows one media item belonging to its camera.
+    const targetIDs = new Set<string>();
+    for (const cameraID of cameraIDs) {
+      const targetID = view.queryResults?.getSelectedResult(cameraID)?.getID();
+      if (targetID) {
+        targetIDs.add(targetID);
+      }
+    }
+    return targetIDs;
+  }
+
+  return null;
+};
+
+// Every target the current view lays out, one per cell. A grid shows several
+// targets at once, so all of them count even when some are scrolled out of the
+// viewport: the user chose to put them on screen. Every other layout shows a
+// single target at a time, which is the one the view identifies.
+export const getDisplayedTargetIDs = (
+  view: View,
+  cameraManager: CameraManager,
+): Set<string> => {
+  const gridTargetIDs = getGridTargetIDs(view, cameraManager);
+  if (gridTargetIDs) {
+    return gridTargetIDs;
+  }
+
+  const targetID = getViewTargetID(view);
+  return targetID ? new Set([targetID]) : new Set();
+};

src/view/view.ts

@@ -70,7 +70,7 @@ const isGalleryViewName = (view?: AdvancedCameraCardView): boolean =>
 const isAnyFolderViewName = (view?: AdvancedCameraCardView): boolean =>
   !!view && FOLDER_VIEW_NAMES.includes(view);
 
-export const isAnyMediaViewName = (view?: AdvancedCameraCardView): boolean =>
+const isAnyMediaViewName = (view?: AdvancedCameraCardView): boolean =>
   isViewerViewName(view) || view === 'live' || view === 'image';
 
 export class View {

tests/browser/mounted-card.ts

@@ -607,10 +607,31 @@ export class MountedCard {
     control.click();
   }
 
+  /**
+   * Click the control that steps a carousel one item along.
+   *
+   * These carry the name of whatever they move to rather than a name of their
+   * own, which several other controls also carry, so they are reached by the
+   * side they sit on instead. Which side moves forward depends on the reading
+   * direction of the page, exactly as it does for the user.
+   */
+  public async clickNextPreviousControl(side: 'left' | 'right'): Promise<void> {
+    const control = await this.waitForRender(
+      () => deepQuery<HTMLElement>(this.card, `ha-icon-button.controls.${side}`),
+      `the ${side} carousel control`,
+    );
+
+    await clickElement(control);
+  }
+
   private async _findControl(name: string): Promise<HTMLElement> {
     return await this.waitForRender(() => {
       const found = deepQueryAll(this.card, '*').find(
-        (element) => getControlName(element) === name,
+        (element) =>
+          getControlName(element) === name &&
+          // A control the user can press occupies space. An element that only
+          // wraps one can carry the same name while having no box of its own.
+          !!element.getBoundingClientRect().width,
       );
       return found instanceof HTMLElement ? found : null;
     }, `a control named ${name}`);

tests/browser/test-utils.ts

@@ -90,7 +90,7 @@ export const createUnansweredMediaURL = (): string => createMediaURL([]);
  */
 export const createStallingMediaURL = (): string => createMediaURL([HTTP_OK]);
 
-export interface StillCameraHASSOptions {
+export interface CameraHASSOptions {
   // Camera entities beyond the default one.
   cameras?: string[];
 
@@ -105,7 +105,7 @@ export interface StillCameraHASSOptions {
  * A Home Assistant holding the cameras a card is about to be given, which is
  * the minimum any browser test needs before it can mount anything.
  */
-export const createStillCameraHASS = (options?: StillCameraHASSOptions): FakeHASS => {
+export const createCameraHASS = (options?: CameraHASSOptions): FakeHASS => {
   const cameras = [STILL_CAMERA_ENTITY, ...(options?.cameras ?? [])];
 
   return new FakeHASS({

tests/camera-manager/manager.browser.test.ts

@@ -3,7 +3,7 @@ import { describe, expect, it, vi } from 'vitest';
 import type { RawAdvancedCameraCardConfig } from '../../src/config/types';
 import { MountedCardFactory, type MountedCard } from '../browser/mounted-card';
 import {
-  createStillCameraHASS,
+  createCameraHASS,
   createStillImageCameraConfig,
   createStillImageCardConfig,
   getBlockNotificationText,
@@ -43,7 +43,7 @@ describe('CameraManager', () => {
         ],
         view: { issues: { retry_seconds: 0 } },
       }),
-      createStillCameraHASS({
+      createCameraHASS({
         cameras: [TRIGGERING_CAMERA_ENTITY, OTHER_TRIGGERING_CAMERA_ENTITY],
       }),
     );
@@ -64,7 +64,7 @@ describe('CameraManager', () => {
       createStillImageCardConfig({
         cameras: [createSubscribingCameraConfig(TRIGGERING_CAMERA_ENTITY)],
       }),
-      createStillCameraHASS({ cameras: [TRIGGERING_CAMERA_ENTITY] }),
+      createCameraHASS({ cameras: [TRIGGERING_CAMERA_ENTITY] }),
     );
 
     await vi.waitFor(() => expect(card.getOpenEventSubscriptionCount()).toBe(1));

tests/card-controller/automations-manager.browser.test.ts

@@ -1,15 +1,12 @@
 import { describe, expect, it } from 'vitest';
 
 import { MountedCardFactory, type MountedCard } from '../browser/mounted-card';
-import {
-  createStillCameraHASS,
-  createStillImageCardConfig,
-} from '../browser/test-utils';
+import { createCameraHASS, createStillImageCardConfig } from '../browser/test-utils';
 
 const TRIGGER_ENTITY = 'input_boolean.zoom';
 
 const mount = async (): Promise<MountedCard> => {
-  const hass = createStillCameraHASS({ entities: { [TRIGGER_ENTITY]: 'off' } });
+  const hass = createCameraHASS({ entities: { [TRIGGER_ENTITY]: 'off' } });
   return await MountedCardFactory.createFromSource(
     createStillImageCardConfig({
       automations: [

tests/card-controller/card-element-manager.browser.test.ts

@@ -4,8 +4,8 @@ import { createLogAction } from '../../src/utils/action';
 import { MountedCardFactory, type MountedCard } from '../browser/mounted-card';
 import {
   CARD_INITIALIZED_MESSAGE,
+  createCameraHASS,
   createInitializedAutomation,
-  createStillCameraHASS,
   createStillImageCardConfig,
   deepQueryAll,
   getFocusedElement,
@@ -28,7 +28,7 @@ const mountCard = async (): Promise<MountedCard> => {
         },
       ],
     }),
-    createStillCameraHASS(),
+    createCameraHASS(),
   );
 
   await card.events.waitForFirst('advanced-camera-card:media:loaded');

tests/card-controller/initialization/session-manager.browser.test.ts

@@ -4,8 +4,8 @@ import type { RawAdvancedCameraCardConfig } from '../../../src/config/types';
 import { MountedCardFactory, type MountedCard } from '../../browser/mounted-card';
 import {
   CARD_INITIALIZED_MESSAGE,
+  createCameraHASS,
   createInitializedAutomation,
-  createStillCameraHASS,
   createStillImageCameraConfig,
   createStillImageCardConfig,
   isMediaLoadedInfoEventDetail,
@@ -26,7 +26,7 @@ const mount = async (
 ): Promise<MountedCard> =>
   await MountedCardFactory.createFromSource(
     createConfig(overrides),
-    createStillCameraHASS({ cameras: [OTHER_CAMERA_ENTITY] }),
+    createCameraHASS({ cameras: [OTHER_CAMERA_ENTITY] }),
   );
 
 // The cameras the card has actually loaded media for, in order. Media that

tests/card-controller/issues/factory.test.ts

@@ -5,6 +5,7 @@ import { createIssueManager } from '../../../src/card-controller/issues/factory'
 import { IssueManager } from '../../../src/card-controller/issues/issue-manager';
 import { ConditionStateManager } from '../../../src/condition-trigger/conditions/state-manager';
 import { createCardAPI } from '../../test-utils';
+import { createView } from '../../view/test-utils';
 import { createSubscriptionHealth } from '../test-utils';
 
 describe('createIssueManager', () => {
@@ -77,23 +78,49 @@ describe('createIssueManager', () => {
     ]);
   });
 
-  it('should wire changeCallback so timer-based issues activate via evaluate', () => {
+  it('should wire changeCallback so an issue can ask for a re-evaluation', () => {
+    const api = createCardAPI();
+    vi.mocked(api.getConditionStateManager).mockReturnValue(new ConditionStateManager());
+    const health = createSubscriptionHealth();
+
+    const manager = createIssueManager(api, health);
+    vi.mocked(api.getCardElementManager().update).mockClear();
+
+    // A subscription starts failing. Nothing has asked the IssueManager to
+    // re-evaluate, so it does not know yet.
+    health.getFailures.mockReturnValue([{ key: 'camera-1', error: 'failed' }]);
+    expect(api.getCardElementManager().update).not.toHaveBeenCalled();
+
+    // The callback EventSubscriptionIssue registered is what asks it to
+    // re-evaluate.
+    const changeCallback = health.addListener.mock.calls[0][0];
+    changeCallback();
+
+    expect(manager.getStateManager().getIssuePresence().has('event_subscription')).toBe(
+      true,
+    );
+    expect(api.getCardElementManager().update).toHaveBeenCalled();
+  });
+
+  it('should report a media failure raised by a component', () => {
     const api = createCardAPI();
     const stateManager = new ConditionStateManager();
     vi.mocked(api.getConditionStateManager).mockReturnValue(stateManager);
+    vi.mocked(api.getViewManager().getView).mockReturnValue(
+      createView({ view: 'live', camera: 'camera-1' }),
+    );
 
     const manager = createIssueManager(api, createSubscriptionHealth());
 
-    // Setting view starts the media_unavailable timer (via the condition state
-    // listener → evaluate → detectDynamic).
     stateManager.setState({ targetID: 'camera-1', view: 'live' });
     expect(manager.getStateManager().getIssuePresence().has('media_unavailable')).toBe(
       false,
     );
 
-    // After the timeout, the changeCallback fires evaluate which
-    // updates the card element.
-    vi.advanceTimersByTime(10000);
+    manager.trigger('media_unavailable', {
+      targetID: 'camera-1',
+      reason: 'not_loading',
+    });
 
     expect(manager.getStateManager().getIssuePresence().has('media_unavailable')).toBe(
       true,

tests/card-controller/issues/issue-manager.test.ts

@@ -24,6 +24,7 @@ import {
   createMediaLoadedInfo,
   flushPromises,
 } from '../../test-utils';
+import { createView } from '../../view/test-utils';
 
 const DEFAULT_RETRY_SECONDS = 1;
 
@@ -120,6 +121,9 @@ describe('IssueManager', () => {
     const api = createCardAPI();
     const conditionStateManager = new ConditionStateManager();
     vi.mocked(api.getConditionStateManager).mockReturnValue(conditionStateManager);
+    vi.mocked(api.getViewManager().getView).mockReturnValue(
+      createView({ view: 'live', camera: 'camera.office' }),
+    );
 
     const manager = new IssueManager(api);
     const issue = new MediaUnavailableIssue(api);

tests/card-controller/issues/issues/initialization.browser.test.ts

@@ -3,8 +3,8 @@ import { describe, expect, it, vi } from 'vitest';
 import { MountedCardFactory, type MountedCard } from '../../../browser/mounted-card';
 import {
   CARD_INITIALIZED_MESSAGE,
+  createCameraHASS,
   createInitializedAutomation,
-  createStillCameraHASS,
   createStillImageCameraConfig,
   createStillImageCardConfig,
   getBlockNotificationText,
@@ -40,7 +40,7 @@ const mountBrokenCard = async (): Promise<MountedCard> =>
       view: { issues: { retry_seconds: 0 } },
       automations: [createInitializedAutomation()],
     }),
-    createStillCameraHASS(),
+    createCameraHASS(),
   );
 
 describe('InitializationIssue', () => {

tests/card-controller/issues/issues/media-unavailable.browser.test.ts

@@ -1,8 +1,8 @@
-import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { afterEach, assert, beforeEach, describe, expect, it, vi } from 'vitest';
 
 import { RETRY_EXPONENTIAL_BASE_SECONDS } from '../../../../src/card-controller/issues/issue-manager';
-import { MEDIA_LOADING_TIMEOUT_SECONDS } from '../../../../src/card-controller/issues/issues/media-unavailable';
 import { LIVENESS_ENTITY_UNAVAILABLE_GRACE_SECONDS } from '../../../../src/components-lib/live/liveness/detectors/entity-availability';
+import { MEDIA_LOADING_TIMEOUT_SECONDS } from '../../../../src/components-lib/media-load-watchdog-controller';
 import { FRAME_STALL_SECONDS } from '../../../../src/components-lib/media-player/frame-stall-watchdog';
 import type { RawAdvancedCameraCardConfig } from '../../../../src/config/types';
 import {
@@ -12,9 +12,9 @@ import {
 } from '../../../browser/mounted-card';
 import { useTestMedia } from '../../../browser/test-media';
 import {
+  createCameraHASS,
   createFailingMediaURL,
   createStallingMediaURL,
-  createStillCameraHASS,
   createStillImageCameraConfig,
   createStillImageCardConfig,
   createTemporarilyFailingMediaURL,
@@ -24,10 +24,13 @@ import {
   getBlockNotificationText,
   isLiveMediaShowing,
   STILL_CAMERA_ENTITY,
+  type CameraHASSOptions,
 } from '../../../browser/test-utils';
 
 const SECOND_CAMERA_ENTITY = 'camera.hallway';
 
+const OVERRIDE_ENTITY = 'input_boolean.override';
+
 const MEDIA_ISSUE_TITLE = 'Media unavailable';
 
 // Holding this reaches the diagnostics view, the only view showing no media
@@ -41,6 +44,17 @@ const findIssue = (card: MountedCard): Element | null =>
 
 const isIssueReported = (card: MountedCard): boolean => !!findIssue(card);
 
+// Resolve once `image` holds a picture that actually loaded. A failed load also
+// marks the element complete, so the decoded size is what separates the two.
+const waitForImageLoaded = async (image: HTMLImageElement): Promise<void> =>
+  await new Promise<void>((resolve) => {
+    if (image.complete && image.naturalWidth > 0) {
+      resolve();
+    } else {
+      image.addEventListener('load', () => resolve(), { once: true });
+    }
+  });
+
 const waitForIssueReported = async (card: MountedCard): Promise<void> => {
   await card.waitForRender(
     () => findIssue(card),
@@ -48,9 +62,14 @@ const waitForIssueReported = async (card: MountedCard): Promise<void> => {
   );
 };
 
-interface MountCardOptions extends MountOptions {
-  cameras?: string[];
-}
+const waitForIssueCleared = async (card: MountedCard): Promise<void> => {
+  await card.waitForRender(
+    () => !findIssue(card) || null,
+    `the ${MEDIA_ISSUE_TITLE} issue being cleared`,
+  );
+};
+
+interface MountCardOptions extends MountOptions, CameraHASSOptions {}
 
 /**
  * Every test here needs the status bar rendered, since that is where an issue
@@ -60,11 +79,11 @@ const mountCard = async (
   config?: Partial<RawAdvancedCameraCardConfig>,
   options?: MountCardOptions,
 ): Promise<MountedCard> => {
-  const { cameras, ...mountOptions } = options ?? {};
+  const { cameras, entities, language, ...mountOptions } = options ?? {};
 
   return await MountedCardFactory.createFromSource(
     createStillImageCardConfig({ status_bar: { style: 'outside' }, ...config }),
-    createStillCameraHASS({ cameras }),
+    createCameraHASS({ cameras, entities, language }),
     mountOptions,
   );
 };
@@ -77,17 +96,22 @@ const mountCardSingleCamera = async (): Promise<MountedCard> => {
   return card;
 };
 
-const mountCardDualCameras = async (): Promise<MountedCard> => {
-  const card = await mountCard(
-    {
-      live: { display: { mode: 'grid' } },
-      cameras: [
-        createStillImageCameraConfig(),
-        createStillImageCameraConfig(SECOND_CAMERA_ENTITY),
-      ],
+/**
+ * A grid of the two standard cameras, which differ only in how they are
+ * configured to behave.
+ */
+const mountCardGrid = async (
+  cameras: RawAdvancedCameraCardConfig[],
+  options?: {
+    config?: Partial<RawAdvancedCameraCardConfig>;
+    entities?: CameraHASSOptions['entities'];
   },
+): Promise<MountedCard> =>
+  await mountCard(
+    { live: { display: { mode: 'grid' } }, cameras, ...options?.config },
     {
       cameras: [SECOND_CAMERA_ENTITY],
+      ...(options?.entities && { entities: options.entities }),
 
       // The grid observes both its own size and its cells', so a cell resize
       // can resize the host and vice versa. Chromium reports each round it has
@@ -100,6 +124,12 @@ const mountCardDualCameras = async (): Promise<MountedCard> => {
     },
   );
 
+const mountCardDualCameras = async (): Promise<MountedCard> => {
+  const card = await mountCardGrid([
+    createStillImageCameraConfig(),
+    createStillImageCameraConfig(SECOND_CAMERA_ENTITY),
+  ]);
+
   await card.events.waitForFirst('advanced-camera-card:media:loaded');
 
   return card;
@@ -182,6 +212,149 @@ describe('MediaUnavailableIssue', () => {
     expect(isLiveMediaShowing(card.card)).toBe(true);
   });
 
+  it('should offer no scrollbar on a failed grid camera that is not selected', async () => {
+    const card = await mountCardDualCameras();
+
+    card.setEntityState(SECOND_CAMERA_ENTITY, 'unavailable');
+    await card.advanceSeconds(LIVENESS_ENTITY_UNAVAILABLE_GRACE_SECONDS);
+    const block = await card.waitForSelector('advanced-camera-card-notification-block');
+
+    // Unselected cells cannot usefully be scrolled, so a scrollbar is not offered.
+    const content = block.shadowRoot?.querySelector('.content');
+    assert(content);
+
+    expect(getComputedStyle(content).overflowY).toBe('hidden');
+  });
+
+  it('should trigger an issue for an unselected grid camera and recover it', async () => {
+    // Every camera in a grid is on screen, so any of them failing triggers an
+    // issue, not only the camera that happens to be selected.
+    // See: https://github.com/dermotduffy/advanced-camera-card/issues/2637
+    const card = await mountCardGrid([
+      createStillImageCameraConfig(),
+      createStillImageCameraConfig(
+        SECOND_CAMERA_ENTITY,
+        createTemporarilyFailingMediaURL(1),
+      ),
+    ]);
+
+    await card.events.waitForFirst('advanced-camera-card:issue:trigger');
+    await waitForIssueReported(card);
+
+    expect(getBlockNotificationText(card.card)).toContain(SECOND_CAMERA_ENTITY);
+
+    // Nothing here asks the card to try again: the retry runs on its own.
+    await card.advanceSeconds(RETRY_EXPONENTIAL_BASE_SECONDS);
+    await waitForIssueCleared(card);
+
+    expect(isLiveMediaShowing(card.card)).toBe(true);
+  });
+
+  it('should trigger an issue for a camera added to a grid by an override', async () => {
+    // Overrides don't recreate views. If an override changes the cameras,
+    // issues should be created for newly added cameras.
+    const card = await mountCardGrid([createStillImageCameraConfig()], {
+      entities: { [OVERRIDE_ENTITY]: 'off' },
+      config: {
+        overrides: [
+          {
+            conditions: [{ condition: 'state', entity: OVERRIDE_ENTITY, state: 'on' }],
+            set: {
+              cameras: [
+                createStillImageCameraConfig(),
+                createStillImageCameraConfig(
+                  SECOND_CAMERA_ENTITY,
+                  createFailingMediaURL(),
+                ),
+              ],
+            },
+          },
+        ],
+      },
+    });
+
+    await card.events.waitForFirst('advanced-camera-card:media:loaded');
+    expect(isIssueReported(card)).toBe(false);
+
+    card.setEntityState(OVERRIDE_ENTITY, 'on');
+
+    await card.events.waitForFirst('advanced-camera-card:issue:trigger');
+    await waitForIssueReported(card);
+
+    expect(getBlockNotificationText(card.card)).toContain(SECOND_CAMERA_ENTITY);
+  });
+
+  it('should stay silent about a carousel camera that is not on screen', async () => {
+    // A carousel camera that has loaded and failed triggers no issue while it
+    // is off screen. Lazy loading is off so that it does load and fail, rather
+    // than the test passing because nothing was watching it.
+    const card = await mountCard(
+      {
+        live: { lazy_load: false },
+        cameras: [
+          createStillImageCameraConfig(),
+          createStillImageCameraConfig(SECOND_CAMERA_ENTITY),
+        ],
+      },
+      { cameras: [SECOND_CAMERA_ENTITY] },
+    );
+    await card.events.waitForFirst('advanced-camera-card:media:loaded');
+
+    card.setEntityState(SECOND_CAMERA_ENTITY, 'unavailable');
+    await card.advanceSeconds(LIVENESS_ENTITY_UNAVAILABLE_GRACE_SECONDS * 4);
+
+    expect(isIssueReported(card)).toBe(false);
+
+    // Step the carousel on to that same camera, which reports the failure it
+    // already had. The silence above was the scoping, not an absence of
+    // anything watching.
+    await card.clickNextPreviousControl('right');
+    await waitForIssueReported(card);
+
+    expect(getBlockNotificationText(card.card)).toContain(SECOND_CAMERA_ENTITY);
+  });
+
+  it('should keep an issue across a detach and re-attach', async () => {
+    const card = await mountCardDualCameras();
+
+    card.setEntityState(SECOND_CAMERA_ENTITY, 'unavailable');
+    await card.advanceSeconds(LIVENESS_ENTITY_UNAVAILABLE_GRACE_SECONDS);
+    await waitForIssueReported(card);
+
+    card.detach();
+    card.attach();
+    await card.updateComplete;
+
+    // The clock has not moved, so a failure found all over again could not have
+    // been reported yet. This is the issue from before the detach.
+    expect(isIssueReported(card)).toBe(true);
+  });
+
+  it('should trigger an issue for a grid camera that goes quiet without failing', async () => {
+    // No active errors, just an unanswered load on an unselected camera.
+    const card = await mountCardGrid([
+      createStillImageCameraConfig(),
+      createStillImageCameraConfig(SECOND_CAMERA_ENTITY, createUnansweredMediaURL()),
+    ]);
+
+    // Nothing is waited on until the cell has a player asking for media.
+    await card.waitForSelector('advanced-camera-card-live-image');
+
+    await card.advanceSeconds(MEDIA_LOADING_TIMEOUT_SECONDS - 1);
+    expect(isIssueReported(card)).toBe(false);
+
+    await card.advanceSeconds(1);
+    await waitForIssueReported(card);
+
+    // The cell itself is still showing that it is waiting, so which camera has
+    // given up is only knowable from the issue.
+    await card.clickControl(MEDIA_ISSUE_TITLE);
+    const notification = await card.waitForSelector('advanced-camera-card-notification');
+
+    expect(notification.shadowRoot?.textContent).toContain(SECOND_CAMERA_ENTITY);
+    expect(notification.shadowRoot?.textContent).toContain('Media not loading');
+  });
+
   it('should report a camera whose media fails to load', async () => {
     const card = await mountCard({
       cameras: [
@@ -392,6 +565,44 @@ describe('MediaUnavailableIssue', () => {
     expect(getBlockNotificationText(card.card)).toContain('Stream stalled');
   });
 
+  it('should trigger an issue for a camera picture that falls back to a stock image', async () => {
+    // A camera-mode image that cannot be fetched swaps in a bundled stock
+    // picture, so something is always on screen. That substitute must not be
+    // announced as the camera's media arriving, or the failure it replaced
+    // would be reported as recovered.
+    const card = await MountedCardFactory.createFromSource(
+      createStillImageCardConfig({
+        status_bar: { style: 'outside' },
+        cameras: [
+          {
+            camera_entity: STILL_CAMERA_ENTITY,
+            live_provider: 'image',
+            image: { mode: 'camera' },
+          },
+        ],
+      }),
+      createCameraHASS({
+        entities: {
+          [STILL_CAMERA_ENTITY]: {
+            state: 'idle',
+            attributes: { entity_picture: createFailingMediaURL() },
+          },
+        },
+      }),
+    );
+
+    const image = await card.waitForSelector<HTMLImageElement>('img');
+    await card.events.waitForFirst('advanced-camera-card:issue:trigger');
+
+    // The stock picture is being swapped into the same element. Wait for that
+    // load specifically: it is the one that could be mistaken for the camera's
+    // media arriving.
+    await waitForImageLoaded(image);
+
+    expect(isIssueReported(card)).toBe(true);
+    expect(card.events.getEntries('advanced-camera-card:media:loaded')).toHaveLength(0);
+  });
+
   it('should report a player that reports a playback error', async () => {
     const card = await mountCard({
       // A provider given nothing to play. It reports that it failed without

tests/card-controller/keyboard-state-manager.browser.test.ts

@@ -10,8 +10,8 @@ import {
 import {
   CARD_INITIALIZED_MESSAGE,
   clickElement,
+  createCameraHASS,
   createInitializedAutomation,
-  createStillCameraHASS,
   createStillImageCardConfig,
   dispatchPointerDown,
   getFocusedElement,
@@ -106,7 +106,7 @@ const mountCard = async (options?: MountCardOptions): Promise<MountedCard> => {
         },
       ],
     }),
-    createStillCameraHASS({ entities: { [ZOOM_ENTITY]: 'off' } }),
+    createCameraHASS({ entities: { [ZOOM_ENTITY]: 'off' } }),
     mountOptions,
   );
 

tests/card-controller/style-manager.browser.test.ts

@@ -1,10 +1,7 @@
 import { describe, expect, it } from 'vitest';
 
 import { MountedCardFactory } from '../browser/mounted-card';
-import {
-  createStillCameraHASS,
-  createStillImageCardConfig,
-} from '../browser/test-utils';
+import { createCameraHASS, createStillImageCardConfig } from '../browser/test-utils';
 
 // A colour the dark theme sets and the card carries no other way. Reading it
 // back proves the stylesheet reached the card rather than merely compiling.
@@ -14,7 +11,7 @@ const DARK_PRIMARY_BACKGROUND = '#111111';
 const mountThemed = async (themes: string[]) =>
   await MountedCardFactory.createFromSource(
     createStillImageCardConfig({ view: { theme: { themes } } }),
-    createStillCameraHASS(),
+    createCameraHASS(),
   );
 
 describe('themes', () => {

tests/components-lib/media-load-watchdog-controller.test.ts

@@ -0,0 +1,455 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+import type {
+  IssueResolveEventData,
+  IssueTriggerEventData,
+} from '../../src/card-controller/issues/types';
+import {
+  MEDIA_LOADING_TIMEOUT_SECONDS,
+  MediaLoadWatchdogController,
+} from '../../src/components-lib/media-load-watchdog-controller';
+import { createLitElement, createMediaLoadedInfo } from '../test-utils';
+
+const TIMEOUT_MS = MEDIA_LOADING_TIMEOUT_SECONDS * 1000;
+
+const createHarness = (options?: {
+  targetID?: string | null;
+  loadExpected?: boolean;
+}) => {
+  const host = createLitElement();
+  let targetID = options?.targetID === undefined ? 'camera-1' : options.targetID;
+  let loadExpected = options?.loadExpected ?? true;
+  let attemptID = 0;
+
+  const triggerRequests: IssueTriggerEventData[] = [];
+  host.addEventListener('advanced-camera-card:issue:trigger', (ev: Event) => {
+    triggerRequests.push((ev as CustomEvent<IssueTriggerEventData>).detail);
+  });
+
+  const resolveRequests: IssueResolveEventData[] = [];
+  host.addEventListener('advanced-camera-card:issue:resolve', (ev: Event) => {
+    resolveRequests.push((ev as CustomEvent<IssueResolveEventData>).detail);
+  });
+
+  const controller = new MediaLoadWatchdogController(host, {
+    getTargetID: () => targetID,
+    isLoadExpected: () => loadExpected,
+    getAttemptID: () => attemptID,
+  });
+
+  return {
+    host,
+    controller,
+    triggerRequests,
+    resolveRequests,
+    setTargetID: (value: string | null): void => {
+      targetID = value;
+    },
+    setLoadExpected: (value: boolean): void => {
+      loadExpected = value;
+    },
+    retryMedia: (): void => {
+      attemptID++;
+    },
+    connect: (): void => controller.hostConnected(),
+    disconnect: (): void => controller.hostDisconnected(),
+    update: (): void => controller.hostUpdated(),
+
+    // Deliver a `media:loaded` as a descendant player would, returning the
+    // controller that makes that media go away.
+    mediaLoaded: (loadedTargetID: string): AbortController => {
+      const abort = new AbortController();
+      host.dispatchEvent(
+        new CustomEvent('advanced-camera-card:media:loaded', {
+          bubbles: true,
+          composed: true,
+          detail: {
+            info: createMediaLoadedInfo({ targetID: loadedTargetID }),
+            signal: abort.signal,
+          },
+        }),
+      );
+      return abort;
+    },
+  };
+};
+
+// @vitest-environment jsdom
+describe('MediaLoadWatchdogController', () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  it('should register itself with the host', () => {
+    const harness = createHarness();
+
+    expect(harness.host.addController).toHaveBeenCalledWith(harness.controller);
+  });
+
+  it('should report a load that never arrives', () => {
+    const harness = createHarness();
+    harness.connect();
+
+    vi.advanceTimersByTime(TIMEOUT_MS);
+
+    expect(harness.triggerRequests).toEqual([
+      { key: 'media_unavailable', targetID: 'camera-1', reason: 'not_loading' },
+    ]);
+  });
+
+  it('should not report a load that arrives in time', () => {
+    const harness = createHarness();
+    harness.connect();
+
+    vi.advanceTimersByTime(TIMEOUT_MS - 1);
+    harness.mediaLoaded('camera-1');
+    vi.advanceTimersByTime(TIMEOUT_MS);
+
+    expect(harness.triggerRequests).toEqual([]);
+  });
+
+  it('should report only once for a target that stays hung', () => {
+    const harness = createHarness();
+    harness.connect();
+
+    vi.advanceTimersByTime(TIMEOUT_MS);
+    harness.update();
+    vi.advanceTimersByTime(TIMEOUT_MS * 5);
+
+    expect(harness.triggerRequests).toHaveLength(1);
+  });
+
+  it('should not wait when no load is expected', () => {
+    const harness = createHarness({ loadExpected: false });
+    harness.connect();
+
+    vi.advanceTimersByTime(TIMEOUT_MS);
+
+    expect(harness.triggerRequests).toEqual([]);
+  });
+
+  it('should not wait without a target', () => {
+    const harness = createHarness({ targetID: null });
+    harness.connect();
+
+    vi.advanceTimersByTime(TIMEOUT_MS);
+
+    expect(harness.triggerRequests).toEqual([]);
+  });
+
+  it('should give a fresh window to a load that becomes expected again', () => {
+    const harness = createHarness({ loadExpected: false });
+    harness.connect();
+
+    vi.advanceTimersByTime(TIMEOUT_MS);
+    harness.setLoadExpected(true);
+    harness.update();
+
+    vi.advanceTimersByTime(TIMEOUT_MS - 1);
+    expect(harness.triggerRequests).toEqual([]);
+
+    vi.advanceTimersByTime(1);
+    expect(harness.triggerRequests).toHaveLength(1);
+  });
+
+  it('should not report once the host stops expecting a load', () => {
+    const harness = createHarness();
+    harness.connect();
+
+    vi.advanceTimersByTime(TIMEOUT_MS - 1);
+    harness.setLoadExpected(false);
+    vi.advanceTimersByTime(1);
+
+    expect(harness.triggerRequests).toEqual([]);
+  });
+
+  describe('clearing a reported failure', () => {
+    it('should clear the failure when media arrives', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      vi.advanceTimersByTime(TIMEOUT_MS);
+      harness.mediaLoaded('camera-1');
+
+      expect(harness.resolveRequests).toEqual([
+        { key: 'media_unavailable', targetID: 'camera-1', reason: 'not_loading' },
+      ]);
+    });
+
+    it('should clear a failure it never reported itself', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      // Another component can report the same kind of failure for this target.
+      harness.mediaLoaded('camera-1');
+
+      expect(harness.resolveRequests).toEqual([
+        { key: 'media_unavailable', targetID: 'camera-1', reason: 'not_loading' },
+      ]);
+    });
+
+    it('should not clear anything for a load belonging to another target', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      harness.mediaLoaded('camera-2');
+
+      expect(harness.resolveRequests).toEqual([]);
+    });
+  });
+
+  describe('media going away', () => {
+    it('should wait again when loaded media goes away', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      const abort = harness.mediaLoaded('camera-1');
+      vi.advanceTimersByTime(TIMEOUT_MS * 2);
+      expect(harness.triggerRequests).toEqual([]);
+
+      abort.abort();
+      vi.advanceTimersByTime(TIMEOUT_MS);
+
+      expect(harness.triggerRequests).toHaveLength(1);
+    });
+
+    it('should ignore an older load going away after a newer one', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      const stale = harness.mediaLoaded('camera-1');
+      harness.mediaLoaded('camera-1');
+
+      stale.abort();
+      vi.advanceTimersByTime(TIMEOUT_MS);
+
+      expect(harness.triggerRequests).toEqual([]);
+    });
+
+    it('should wait again when media went away while the host was disconnected', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      const abort = harness.mediaLoaded('camera-1');
+      harness.disconnect();
+      abort.abort();
+
+      // A detached host is not waited on, so nothing is reported yet.
+      vi.advanceTimersByTime(TIMEOUT_MS);
+      expect(harness.triggerRequests).toEqual([]);
+
+      // The media that went away is gone on return, so the wait resumes rather
+      // than the host being taken to still have it.
+      harness.connect();
+      vi.advanceTimersByTime(TIMEOUT_MS);
+
+      expect(harness.triggerRequests).toEqual([
+        { key: 'media_unavailable', targetID: 'camera-1', reason: 'not_loading' },
+      ]);
+    });
+  });
+
+  describe('a host reused for another target', () => {
+    it('should not treat a load for another target as its own', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      harness.mediaLoaded('camera-2');
+      vi.advanceTimersByTime(TIMEOUT_MS);
+
+      expect(harness.triggerRequests).toEqual([
+        { key: 'media_unavailable', targetID: 'camera-1', reason: 'not_loading' },
+      ]);
+    });
+
+    it('should not carry a previous load over to the next target', () => {
+      const harness = createHarness();
+      harness.connect();
+      harness.mediaLoaded('camera-1');
+
+      harness.setTargetID('camera-2');
+      harness.update();
+      vi.advanceTimersByTime(TIMEOUT_MS);
+
+      expect(harness.triggerRequests).toEqual([
+        { key: 'media_unavailable', targetID: 'camera-2', reason: 'not_loading' },
+      ]);
+    });
+
+    it('should give the next target a full window rather than what remained', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      vi.advanceTimersByTime(TIMEOUT_MS - 1);
+      harness.setTargetID('camera-2');
+      harness.update();
+
+      vi.advanceTimersByTime(TIMEOUT_MS - 1);
+      expect(harness.triggerRequests).toEqual([]);
+
+      vi.advanceTimersByTime(1);
+      expect(harness.triggerRequests).toEqual([
+        { key: 'media_unavailable', targetID: 'camera-2', reason: 'not_loading' },
+      ]);
+    });
+
+    it('should report the next target after the previous one was reported', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      vi.advanceTimersByTime(TIMEOUT_MS);
+      harness.setTargetID('camera-2');
+      harness.update();
+      vi.advanceTimersByTime(TIMEOUT_MS);
+
+      expect(harness.triggerRequests).toEqual([
+        { key: 'media_unavailable', targetID: 'camera-1', reason: 'not_loading' },
+        { key: 'media_unavailable', targetID: 'camera-2', reason: 'not_loading' },
+      ]);
+    });
+
+    it('should resolve a failure it reported for the previous target', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      vi.advanceTimersByTime(TIMEOUT_MS);
+      harness.setTargetID('camera-2');
+      harness.update();
+
+      // Nothing watches camera-1 now, so nothing could ever say it recovered.
+      expect(harness.resolveRequests).toEqual([
+        { key: 'media_unavailable', targetID: 'camera-1', reason: 'not_loading' },
+      ]);
+    });
+
+    it('should resolve a failure when the next target loads immediately', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      vi.advanceTimersByTime(TIMEOUT_MS);
+      harness.setTargetID('camera-2');
+      harness.mediaLoaded('camera-2');
+
+      expect(harness.resolveRequests).toEqual([
+        { key: 'media_unavailable', targetID: 'camera-1', reason: 'not_loading' },
+        { key: 'media_unavailable', targetID: 'camera-2', reason: 'not_loading' },
+      ]);
+    });
+
+    it('should resolve nothing when it reported no failure', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      harness.setTargetID('camera-2');
+      harness.update();
+
+      expect(harness.resolveRequests).toEqual([]);
+    });
+  });
+
+  describe('connection', () => {
+    it('should not wait while disconnected', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      vi.advanceTimersByTime(TIMEOUT_MS - 1);
+      harness.disconnect();
+      vi.advanceTimersByTime(TIMEOUT_MS);
+
+      expect(harness.triggerRequests).toEqual([]);
+    });
+
+    it('should give a fresh window on reconnect', () => {
+      const harness = createHarness();
+      harness.connect();
+      harness.disconnect();
+      harness.connect();
+
+      vi.advanceTimersByTime(TIMEOUT_MS - 1);
+      expect(harness.triggerRequests).toEqual([]);
+
+      vi.advanceTimersByTime(1);
+      expect(harness.triggerRequests).toHaveLength(1);
+    });
+
+    it('should ignore a host update while disconnected', () => {
+      const harness = createHarness();
+
+      harness.update();
+      vi.advanceTimersByTime(TIMEOUT_MS);
+
+      expect(harness.triggerRequests).toEqual([]);
+    });
+  });
+
+  describe('a rebuilt attempt at the same target', () => {
+    it('should wait again after the media underneath is rebuilt', () => {
+      const harness = createHarness();
+      harness.connect();
+      harness.mediaLoaded('camera-1');
+
+      harness.retryMedia();
+      harness.update();
+      vi.advanceTimersByTime(TIMEOUT_MS);
+
+      expect(harness.triggerRequests).toHaveLength(1);
+    });
+
+    it('should report again after a retry of a target already reported', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      vi.advanceTimersByTime(TIMEOUT_MS);
+      harness.retryMedia();
+      harness.update();
+      vi.advanceTimersByTime(TIMEOUT_MS);
+
+      expect(harness.triggerRequests).toHaveLength(2);
+    });
+
+    it('should not report an attempt the retry has already replaced', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      // The retry lands while the window for the previous attempt is still
+      // maturing, and the host has not been updated yet.
+      vi.advanceTimersByTime(TIMEOUT_MS - 1);
+      harness.retryMedia();
+      vi.advanceTimersByTime(1);
+
+      expect(harness.triggerRequests).toEqual([]);
+    });
+
+    it('should keep a reported failure visible while the retry runs', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      vi.advanceTimersByTime(TIMEOUT_MS);
+      harness.retryMedia();
+      harness.update();
+
+      // The target is unchanged, so the failure still describes it until the
+      // retried media either arrives or hangs in its turn.
+      expect(harness.resolveRequests).toEqual([]);
+    });
+
+    it('should give the rebuilt attempt a full window', () => {
+      const harness = createHarness();
+      harness.connect();
+
+      vi.advanceTimersByTime(TIMEOUT_MS - 1);
+      harness.retryMedia();
+      harness.update();
+
+      vi.advanceTimersByTime(TIMEOUT_MS - 1);
+      expect(harness.triggerRequests).toEqual([]);
+
+      vi.advanceTimersByTime(1);
+      expect(harness.triggerRequests).toHaveLength(1);
+    });
+  });
+});

tests/components/image-updating-player.browser.test.ts

@@ -3,7 +3,7 @@ import { describe, expect, it } from 'vitest';
 import type { MediaLoadedInfoEventDetail } from '../../src/types';
 import { MountedCardFactory, type MountedCard } from '../browser/mounted-card';
 import {
-  createStillCameraHASS,
+  createCameraHASS,
   createStillImageCardConfig,
   isMediaLoadedInfoEventDetail,
   STILL_CAMERA_ENTITY,
@@ -22,7 +22,7 @@ interface RenderedElement extends Element {
 }
 
 const mount = async (): Promise<MountedCard> => {
-  const hass = createStillCameraHASS({ entities: { [UNRELATED_ENTITY]: 'off' } });
+  const hass = createCameraHASS({ entities: { [UNRELATED_ENTITY]: 'off' } });
   return await MountedCardFactory.createFromSource(createStillImageCardConfig(), hass);
 };
 

tests/dist/dist.browser.test.ts

@@ -11,7 +11,7 @@ import {
   type MountOptions,
 } from '../browser/mounted-card';
 import {
-  createStillCameraHASS,
+  createCameraHASS,
   createStillImageCardConfig,
   isLiveMediaShowing,
 } from '../browser/test-utils';
@@ -99,7 +99,7 @@ class BuildMountedCardFactory extends MountedCardFactory {
  * rather than from `src/`.
  */
 const mountBuiltCard = async (
-  hass: FakeHASS = createStillCameraHASS(),
+  hass: FakeHASS = createCameraHASS(),
 ): Promise<MountedCard> =>
   await BuildMountedCardFactory.createFromBuild(
     `/${PUBLIC_ENTRY}?hacstag=${HACSTAG}`,
@@ -243,7 +243,7 @@ describe('the built card', () => {
     // Clear resource timings to only measure the impact of mounting the card.
     performance.clearResourceTimings();
 
-    const mounted = await mountBuiltCard(createStillCameraHASS({ language: 'de' }));
+    const mounted = await mountBuiltCard(createCameraHASS({ language: 'de' }));
     await mounted.events.waitForFirst('advanced-camera-card:media:loaded');
 
     expect(getLanguageChunks()).toEqual([expect.stringMatching(/^lang-de-/)]);

tests/view/layout.test.ts

@@ -0,0 +1,191 @@
+import { describe, expect, it } from 'vitest';
+import { mock } from 'vitest-mock-extended';
+
+import type { CameraManager } from '../../src/camera-manager/manager';
+import type { CameraManagerReadOnlyConfigStore } from '../../src/camera-manager/store';
+import {
+  getDisplayedTargetIDs,
+  getLiveGridCameraIDs,
+  getViewerGridCameraIDs,
+} from '../../src/view/layout';
+import { QueryResults } from '../../src/view/query-results';
+import { IMAGE_VIEW_TARGET_ID_SENTINEL } from '../../src/view/target-id';
+import { createView, generateViewMediaArray } from './test-utils';
+
+// A camera manager whose store reports the given live-capable cameras.
+const createCameraManager = (cameraIDs: string[]): CameraManager => {
+  const cameraManager = mock<CameraManager>();
+  const store = mock<CameraManagerReadOnlyConfigStore>();
+  store.getCameraIDsWithCapability.mockReturnValue(new Set(cameraIDs));
+  cameraManager.getStore.mockReturnValue(store);
+  return cameraManager;
+};
+
+// Query results spanning `cameraIDs`, each camera with its own media.
+const createQueryResults = (cameraIDs: string[]): QueryResults =>
+  new QueryResults({
+    results: generateViewMediaArray({ cameraIDs, count: 1 }),
+    selectedIndex: 0,
+  });
+
+describe('getLiveGridCameraIDs', () => {
+  it('should return every live camera when laid out as a grid', () => {
+    const view = createView({ view: 'live', displayMode: 'grid' });
+
+    expect(
+      getLiveGridCameraIDs(view, createCameraManager(['kitchen', 'office'])),
+    ).toEqual(new Set(['kitchen', 'office']));
+  });
+
+  it('should return null when not laid out as a grid', () => {
+    const view = createView({ view: 'live', displayMode: 'single' });
+
+    expect(
+      getLiveGridCameraIDs(view, createCameraManager(['kitchen', 'office'])),
+    ).toBeNull();
+  });
+
+  it('should return null for a view that inherited a grid it cannot use', () => {
+    const view = createView({ view: 'image', displayMode: 'grid' });
+
+    expect(
+      getLiveGridCameraIDs(view, createCameraManager(['kitchen', 'office'])),
+    ).toBeNull();
+  });
+});
+
+describe('getViewerGridCameraIDs', () => {
+  it('should return every camera with media when laid out as a grid', () => {
+    const view = createView({
+      view: 'media',
+      displayMode: 'grid',
+      queryResults: createQueryResults(['kitchen', 'office']),
+    });
+
+    expect(getViewerGridCameraIDs(view)).toEqual(new Set(['kitchen', 'office']));
+  });
+
+  it('should return null when not laid out as a grid', () => {
+    const view = createView({
+      view: 'media',
+      displayMode: 'single',
+      queryResults: createQueryResults(['kitchen', 'office']),
+    });
+
+    expect(getViewerGridCameraIDs(view)).toBeNull();
+  });
+
+  it('should return null for a view that inherited a grid it cannot use', () => {
+    const view = createView({
+      view: 'image',
+      displayMode: 'grid',
+      queryResults: createQueryResults(['kitchen', 'office']),
+    });
+
+    expect(getViewerGridCameraIDs(view)).toBeNull();
+  });
+});
+
+describe('getDisplayedTargetIDs', () => {
+  it('should return every camera of a live grid', () => {
+    const view = createView({ view: 'live', displayMode: 'grid' });
+
+    expect(
+      getDisplayedTargetIDs(view, createCameraManager(['kitchen', 'office'])),
+    ).toEqual(new Set(['kitchen', 'office']));
+  });
+
+  it('should return the selected camera of a live carousel', () => {
+    const view = createView({
+      view: 'live',
+      camera: 'kitchen',
+      displayMode: 'single',
+    });
+
+    expect(
+      getDisplayedTargetIDs(view, createCameraManager(['kitchen', 'office'])),
+    ).toEqual(new Set(['kitchen']));
+  });
+
+  it('should return the selected media of every camera of a viewer grid', () => {
+    const view = createView({
+      view: 'media',
+      displayMode: 'grid',
+      queryResults: createQueryResults(['kitchen', 'office']),
+    });
+
+    expect(getDisplayedTargetIDs(view, createCameraManager([]))).toEqual(
+      new Set(['id-kitchen-0', 'id-office-0']),
+    );
+  });
+
+  it('should return the selected media of a viewer carousel', () => {
+    const view = createView({
+      view: 'media',
+      displayMode: 'single',
+      queryResults: createQueryResults(['kitchen', 'office']),
+    });
+
+    expect(getDisplayedTargetIDs(view, createCameraManager([]))).toEqual(
+      new Set(['id-kitchen-0']),
+    );
+  });
+
+  it('should skip a viewer grid camera without a selected media', () => {
+    const queryResults = createQueryResults(['kitchen', 'office']);
+    queryResults.resetSelectedResult('office');
+    const view = createView({
+      view: 'media',
+      displayMode: 'grid',
+      queryResults,
+    });
+
+    expect(getDisplayedTargetIDs(view, createCameraManager([]))).toEqual(
+      new Set(['id-kitchen-0']),
+    );
+  });
+
+  it('should return the lone camera of a live grid that needs no layout', () => {
+    const view = createView({
+      view: 'live',
+      camera: 'kitchen',
+      displayMode: 'grid',
+    });
+
+    expect(getDisplayedTargetIDs(view, createCameraManager(['kitchen']))).toEqual(
+      new Set(['kitchen']),
+    );
+  });
+
+  it('should return the lone media of a viewer grid that needs no layout', () => {
+    const view = createView({
+      view: 'media',
+      displayMode: 'grid',
+      queryResults: createQueryResults(['kitchen']),
+    });
+
+    expect(getDisplayedTargetIDs(view, createCameraManager([]))).toEqual(
+      new Set(['id-kitchen-0']),
+    );
+  });
+
+  it('should return nothing for a viewer grid without query results', () => {
+    const view = createView({ view: 'media', displayMode: 'grid' });
+
+    expect(getDisplayedTargetIDs(view, createCameraManager([]))).toEqual(new Set());
+  });
+
+  it('should return the sentinel for the image view', () => {
+    const view = createView({ view: 'image' });
+
+    expect(getDisplayedTargetIDs(view, createCameraManager([]))).toEqual(
+      new Set([IMAGE_VIEW_TARGET_ID_SENTINEL]),
+    );
+  });
+
+  it('should return nothing for a view that displays no media', () => {
+    const view = createView({ view: 'timeline' });
+
+    expect(getDisplayedTargetIDs(view, createCameraManager([]))).toEqual(new Set());
+  });
+});