Winter is coming (#28036)

* Winter is coming

* Set max to 30 on mobile

* Change storage key

* Use core

* Add browser level switch for winter mode

* Simplify logic

src/components/ha-snowflakes.ts

@@ -0,0 +1,178 @@
+import { css, html, LitElement, nothing } from "lit";
+import { customElement, property, state } from "lit/decorators";
+import type { HomeAssistant } from "../types";
+import { subscribeLabFeatures } from "../data/labs";
+import { SubscribeMixin } from "../mixins/subscribe-mixin";
+
+interface Snowflake {
+  id: number;
+  left: number;
+  size: number;
+  duration: number;
+  delay: number;
+  blur: number;
+}
+
+@customElement("ha-snowflakes")
+export class HaSnowflakes extends SubscribeMixin(LitElement) {
+  @property({ attribute: false }) public hass?: HomeAssistant;
+
+  @property({ type: Boolean }) public narrow = false;
+
+  @state() private _enabled = false;
+
+  @state() private _snowflakes: Snowflake[] = [];
+
+  private _maxSnowflakes = 50;
+
+  public hassSubscribe() {
+    return [
+      subscribeLabFeatures(this.hass!.connection, (features) => {
+        this._enabled =
+          features.find(
+            (f) =>
+              f.domain === "frontend" && f.preview_feature === "winter_mode"
+          )?.enabled ?? false;
+      }),
+    ];
+  }
+
+  private _generateSnowflakes() {
+    if (!this._enabled) {
+      this._snowflakes = [];
+      return;
+    }
+
+    const snowflakes: Snowflake[] = [];
+    for (let i = 0; i < this._maxSnowflakes; i++) {
+      snowflakes.push({
+        id: i,
+        left: Math.random() * 100, // Random position from 0-100%
+        size: Math.random() * 12 + 8, // Random size between 8-20px
+        duration: Math.random() * 8 + 8, // Random duration between 8-16s
+        delay: Math.random() * 8, // Random delay between 0-8s
+        blur: Math.random() * 1, // Random blur between 0-1px
+      });
+    }
+    this._snowflakes = snowflakes;
+  }
+
+  protected willUpdate(changedProps: Map<string, unknown>) {
+    super.willUpdate(changedProps);
+    if (changedProps.has("_enabled")) {
+      this._generateSnowflakes();
+    }
+  }
+
+  protected render() {
+    if (!this._enabled) {
+      return nothing;
+    }
+
+    const isDark = this.hass?.themes.darkMode ?? false;
+
+    return html`
+      <div class="snowflakes ${isDark ? "dark" : "light"}" aria-hidden="true">
+        ${this._snowflakes.map(
+          (flake) => html`
+            <div
+              class="snowflake ${this.narrow && flake.id >= 30
+                ? "hide-narrow"
+                : ""}"
+              style="
+                left: ${flake.left}%;
+                font-size: ${flake.size}px;
+                animation-duration: ${flake.duration}s;
+                animation-delay: ${flake.delay}s;
+                filter: blur(${flake.blur}px);
+              "
+            >
+              ❄
+            </div>
+          `
+        )}
+      </div>
+    `;
+  }
+
+  static readonly styles = css`
+    :host {
+      display: block;
+      position: fixed;
+      top: 0;
+      left: 0;
+      width: 100%;
+      height: 100%;
+      pointer-events: none;
+      z-index: 9999;
+      overflow: hidden;
+    }
+
+    .snowflakes {
+      position: absolute;
+      top: -10%;
+      left: 0;
+      width: 100%;
+      height: 110%;
+      pointer-events: none;
+    }
+
+    .snowflake {
+      position: absolute;
+      top: -10%;
+      opacity: 0.7;
+      user-select: none;
+      pointer-events: none;
+      animation: fall linear infinite;
+    }
+
+    .light .snowflake {
+      color: #00bcd4;
+      text-shadow:
+        0 0 5px #00bcd4,
+        0 0 10px #00e5ff;
+    }
+
+    .dark .snowflake {
+      color: #fff;
+      text-shadow:
+        0 0 5px rgba(255, 255, 255, 0.8),
+        0 0 10px rgba(255, 255, 255, 0.5);
+    }
+
+    .snowflake.hide-narrow {
+      display: none;
+    }
+
+    @keyframes fall {
+      0% {
+        transform: translateY(-10vh) translateX(0);
+      }
+      25% {
+        transform: translateY(30vh) translateX(10px);
+      }
+      50% {
+        transform: translateY(60vh) translateX(-10px);
+      }
+      75% {
+        transform: translateY(85vh) translateX(10px);
+      }
+      100% {
+        transform: translateY(120vh) translateX(0);
+      }
+    }
+
+    @media (prefers-reduced-motion: reduce) {
+      .snowflake {
+        animation: none;
+        display: none;
+      }
+    }
+  `;
+}
+
+declare global {
+  interface HTMLElementTagNameMap {
+    "ha-snowflakes": HaSnowflakes;
+  }
+}

src/layouts/home-assistant-main.ts

@@ -7,6 +7,7 @@ import { listenMediaQuery } from "../common/dom/media_query";
 import { toggleAttribute } from "../common/dom/toggle_attribute";
 import { computeRTLDirection } from "../common/util/compute_rtl";
 import "../components/ha-drawer";
+import "../components/ha-snowflakes";
 import { showNotificationDrawer } from "../dialogs/notifications/show-notification-drawer";
 import type { HomeAssistant, Route } from "../types";
 import "./partial-panel-resolver";
@@ -50,6 +51,7 @@ export class HomeAssistantMain extends LitElement {
       this.hass.panels && this.hass.userData && this.hass.systemData;
 
     return html`
+      <ha-snowflakes .hass=${this.hass} .narrow=${this.narrow}></ha-snowflakes>
       <ha-drawer
         .type=${sidebarNarrow ? "modal" : ""}
         .open=${sidebarNarrow ? this._drawerOpen : false}