Pause the logbook stream when scrolled (#13026)

src/panels/logbook/ha-logbook-renderer.ts

@@ -1,4 +1,5 @@
 import "@lit-labs/virtualizer";
+import { VisibilityChangedEvent } from "@lit-labs/virtualizer/Virtualizer";
 import {
   css,
   CSSResultGroup,
@@ -34,6 +35,12 @@ import {
 import { HomeAssistant } from "../../types";
 import { brandsUrl } from "../../util/brands-url";
 
+declare global {
+  interface HASSDomEvents {
+    "hass-logbook-live": { enable: boolean };
+  }
+}
+
 const triggerDomains = ["script", "automation"];
 
 const hasContext = (item: LogbookEntry) =>
@@ -102,6 +109,7 @@ class HaLogbookRenderer extends LitElement {
       >
         ${this.virtualize
           ? html`<lit-virtualizer
+              @visibilityChanged=${this._visibilityChanged}
               scroller
               class="ha-scrollbar"
               .items=${this.entries}
@@ -239,6 +247,13 @@ class HaLogbookRenderer extends LitElement {
     this._savedScrollPos = (e.target as HTMLDivElement).scrollTop;
   }
 
+  @eventOptions({ passive: true })
+  private _visibilityChanged(e: VisibilityChangedEvent) {
+    fireEvent(this, "hass-logbook-live", {
+      enable: e.first === 0,
+    });
+  }
+
   private _renderMessage(
     item: LogbookEntry,
     seenEntityIds: string[],

src/panels/logbook/ha-logbook.ts

@@ -80,6 +80,10 @@ export class HaLogbook extends LitElement {
 
   private _subscribed?: Promise<(() => Promise<void>) | void>;
 
+  private _liveUpdatesEnabled = true;
+
+  private _pendingStreamMessages: LogbookStreamMessage[] = [];
+
   private _throttleGetLogbookEntries = throttle(
     () => this._getLogBookData(),
     1000
@@ -126,6 +130,7 @@ export class HaLogbook extends LitElement {
         .entries=${this._logbookEntries}
         .traceContexts=${this._traceContexts}
         .userIdToName=${this._userIdToName}
+        @hass-logbook-live=${this._handleLogbookLive}
       ></ha-logbook-renderer>
     `;
   }
@@ -150,6 +155,10 @@ export class HaLogbook extends LitElement {
     this._throttleGetLogbookEntries();
   }
 
+  protected firstUpdated(changedProps: PropertyValues) {
+    super.firstUpdated(changedProps);
+  }
+
   protected shouldUpdate(changedProps: PropertyValues): boolean {
     if (changedProps.size !== 1 || !changedProps.has("hass")) {
       return true;
@@ -185,6 +194,17 @@ export class HaLogbook extends LitElement {
     }
   }
 
+  private _handleLogbookLive(ev: CustomEvent) {
+    if (ev.detail.enable && !this._liveUpdatesEnabled) {
+      // Process everything we queued up while we were scrolled down
+      this._pendingStreamMessages.forEach((msg) =>
+        this._processStreamMessage(msg)
+      );
+      this._pendingStreamMessages = [];
+    }
+    this._liveUpdatesEnabled = ev.detail.enable;
+  }
+
   private get _filterAlwaysEmptyResults(): boolean {
     const entityIds = ensureArray(this.entityIds);
     const deviceIds = ensureArray(this.deviceIds);
@@ -283,12 +303,7 @@ export class HaLogbook extends LitElement {
           // Message came in before we had a chance to unload
           return;
         }
-        this._processStreamMessage(
-          streamMessage,
-          "recent" in this.time
-            ? findStartOfRecentTime(new Date(), this.time.recent)
-            : undefined
-        );
+        this._processOrQueueStreamMessage(streamMessage);
       },
       logbookPeriod.startTime.toISOString(),
       logbookPeriod.endTime.toISOString(),
@@ -334,10 +349,21 @@ export class HaLogbook extends LitElement {
         )
       : this._logbookEntries;
 
-  private _processStreamMessage = (
-    streamMessage: LogbookStreamMessage,
-    purgeBeforePythonTime: number | undefined
+  private _processOrQueueStreamMessage = (
+    streamMessage: LogbookStreamMessage
   ) => {
+    if (this._liveUpdatesEnabled) {
+      this._processStreamMessage(streamMessage);
+      return;
+    }
+    this._pendingStreamMessages.push(streamMessage);
+  };
+
+  private _processStreamMessage = (streamMessage: LogbookStreamMessage) => {
+    const purgeBeforePythonTime =
+      "recent" in this.time
+        ? findStartOfRecentTime(new Date(), this.time.recent)
+        : undefined;
     // Put newest ones on top. Reverse works in-place so
     // make a copy first.
     const newEntries = [...streamMessage.events].reverse();