refactor(web): extract asset-grid-without-scrubber from asset-grid component

Separated scrubber logic into asset-grid component, creating a
asset-grid-without-scrubber for modularity. Names not final yet,
much more left to do.

Author: midzelis

web/src/lib/components/photos-page/asset-grid-without-scrubber.svelte

@@ -0,0 +1,390 @@
+<script lang="ts">
+  import { afterNavigate, beforeNavigate } from '$app/navigation';
+  import { page } from '$app/stores';
+  import { resizeObserver, type OnResizeCallback } from '$lib/actions/resize-observer';
+  import AssetDateGroupActions from '$lib/components/photos-page/asset-date-group-actions.svelte';
+  import AssetGridActions from '$lib/components/photos-page/asset-grid-actions.svelte';
+  import AssetViewerAndActions from '$lib/components/photos-page/asset-viewer-and-actions.svelte';
+  import Skeleton from '$lib/components/photos-page/skeleton.svelte';
+  import { AssetAction } from '$lib/constants';
+  import type { MonthGroup } from '$lib/managers/timeline-manager/month-group.svelte';
+  import { TimelineManager } from '$lib/managers/timeline-manager/timeline-manager.svelte';
+  import type { TimelineAsset } from '$lib/managers/timeline-manager/types';
+  import type { AssetInteraction } from '$lib/stores/asset-interaction.svelte';
+  import { assetViewingStore } from '$lib/stores/asset-viewing.store';
+  import { mobileDevice } from '$lib/stores/mobile-device.svelte';
+  import { navigate } from '$lib/utils/navigation';
+  import { type AlbumResponseDto, type PersonResponseDto } from '@immich/sdk';
+  import { onMount, type Snippet } from 'svelte';
+  import type { UpdatePayload } from 'vite';
+  import Portal from '../shared-components/portal/portal.svelte';
+  import AssetDateGroup from './asset-date-group.svelte';
+
+  interface Props {
+    isSelectionMode?: boolean;
+    singleSelect?: boolean;
+    /** `true` if this asset grid is responds to navigation events; if `true`, then look at the
+     `AssetViewingStore.gridScrollTarget` and load and scroll to the asset specified, and
+     additionally, update the page location/url with the asset as the asset-grid is scrolled */
+    enableRouting: boolean;
+    timelineManager: TimelineManager;
+    assetInteraction: AssetInteraction;
+    removeAction?:
+      | AssetAction.UNARCHIVE
+      | AssetAction.ARCHIVE
+      | AssetAction.FAVORITE
+      | AssetAction.UNFAVORITE
+      | AssetAction.SET_VISIBILITY_TIMELINE;
+    withStacked?: boolean;
+    showArchiveIcon?: boolean;
+    isShared?: boolean;
+    album?: AlbumResponseDto | null;
+    person?: PersonResponseDto | null;
+    isShowDeleteConfirmation?: boolean;
+    onSelect?: (asset: TimelineAsset) => void;
+    onEscape?: () => void;
+    header?: Snippet<[handleScrollTop: (top: number) => void]>;
+    children?: Snippet;
+    empty?: Snippet;
+    handleTimelineScroll?: () => void;
+  }
+
+  let {
+    isSelectionMode = false,
+    singleSelect = false,
+    enableRouting,
+    timelineManager = $bindable(),
+    assetInteraction,
+    removeAction,
+    withStacked = false,
+    showArchiveIcon = false,
+    isShared = false,
+    album = null,
+    person = null,
+    isShowDeleteConfirmation = $bindable(false),
+    onSelect = () => {},
+    onEscape = () => {},
+    children,
+    empty,
+    header,
+    handleTimelineScroll = () => {},
+  }: Props = $props();
+
+  let { isViewing: showAssetViewer, gridScrollTarget } = assetViewingStore;
+
+  let element: HTMLElement | undefined = $state();
+
+  let timelineElement: HTMLElement | undefined = $state();
+  let showSkeleton = $state(true);
+
+  let scrubberWidth = $state(0);
+
+  // 60 is the bottom spacer element at 60px
+  let bottomSectionHeight = 60;
+  let leadout = $state(false);
+
+  const maxMd = $derived(mobileDevice.maxMd);
+  const usingMobileDevice = $derived(mobileDevice.pointerCoarse);
+  const isEmpty = $derived(timelineManager.isInitialized && timelineManager.months.length === 0);
+
+  $effect(() => {
+    const layoutOptions = maxMd
+      ? {
+          rowHeight: 100,
+          headerHeight: 32,
+        }
+      : {
+          rowHeight: 235,
+          headerHeight: 48,
+        };
+    timelineManager.setLayoutOptions(layoutOptions);
+  });
+
+  const scrollTo = (top: number) => {
+    if (element) {
+      element.scrollTo({ top });
+    }
+  };
+  const scrollTop = (top: number) => {
+    if (element) {
+      element.scrollTop = top;
+    }
+  };
+  const scrollBy = (y: number) => {
+    if (element) {
+      element.scrollBy(0, y);
+    }
+  };
+  const scrollToTop = () => {
+    scrollTo(0);
+  };
+
+  const getAssetHeight = (assetId: string, monthGroup: MonthGroup) => {
+    // the following method may trigger any layouts, so need to
+    // handle any scroll compensation that may have been set
+    const height = monthGroup!.findAssetAbsolutePosition(assetId);
+
+    while (timelineManager.scrollCompensation.monthGroup) {
+      handleScrollCompensation(timelineManager.scrollCompensation);
+      timelineManager.clearScrollCompensation();
+    }
+    return height;
+  };
+
+  const assetIsVisible = (assetTop: number): boolean => {
+    if (!element) {
+      return false;
+    }
+
+    const { clientHeight, scrollTop } = element;
+    return assetTop >= scrollTop && assetTop < scrollTop + clientHeight;
+  };
+
+  const scrollToAssetId = async (assetId: string) => {
+    const monthGroup = await timelineManager.findMonthGroupForAsset(assetId);
+    if (!monthGroup) {
+      return false;
+    }
+    const height = getAssetHeight(assetId, monthGroup);
+
+    // If the asset is already visible, then don't scroll.
+    if (assetIsVisible(height)) {
+      return true;
+    }
+
+    scrollTo(height);
+    updateSlidingWindow();
+    return true;
+  };
+
+  const scrollToAsset = (asset: TimelineAsset) => {
+    const monthGroup = timelineManager.getMonthGroupByAssetId(asset.id);
+    if (!monthGroup) {
+      return false;
+    }
+    const height = getAssetHeight(asset.id, monthGroup);
+    scrollTo(height);
+    updateSlidingWindow();
+    return true;
+  };
+
+  const completeNav = async () => {
+    const scrollTarget = $gridScrollTarget?.at;
+    let scrolled = false;
+    if (scrollTarget) {
+      scrolled = await scrollToAssetId(scrollTarget);
+    }
+    if (!scrolled) {
+      // if the asset is not found, scroll to the top
+      scrollToTop();
+    }
+    showSkeleton = false;
+  };
+
+  beforeNavigate(() => (timelineManager.suspendTransitions = true));
+
+  afterNavigate((nav) => {
+    const { complete } = nav;
+    complete.then(completeNav, completeNav);
+  });
+
+  const hmrSupport = () => {
+    // when hmr happens, skeleton is initialized to true by default
+    // normally, loading asset-grid is part of a navigation event, and the completion of
+    // that event triggers a scroll-to-asset, if necessary, when then clears the skeleton.
+    // this handler will run the navigation/scroll-to-asset handler when hmr is performed,
+    // preventing skeleton from showing after hmr
+    if (import.meta && import.meta.hot) {
+      const afterApdate = (payload: UpdatePayload) => {
+        const assetGridUpdate = payload.updates.some(
+          (update) => update.path.endsWith('asset-grid.svelte') || update.path.endsWith('assets-store.ts'),
+        );
+
+        if (assetGridUpdate) {
+          setTimeout(() => {
+            const asset = $page.url.searchParams.get('at');
+            if (asset) {
+              $gridScrollTarget = { at: asset };
+              void navigate(
+                { targetRoute: 'current', assetId: null, assetGridRouteSearchParams: $gridScrollTarget },
+                { replaceState: true, forceNavigate: true },
+              );
+            } else {
+              scrollToTop();
+            }
+            showSkeleton = false;
+          }, 500);
+        }
+      };
+      import.meta.hot?.on('vite:afterUpdate', afterApdate);
+      import.meta.hot?.on('vite:beforeUpdate', (payload) => {
+        const assetGridUpdate = payload.updates.some((update) => update.path.endsWith('asset-grid.svelte'));
+        if (assetGridUpdate) {
+          timelineManager.destroy();
+        }
+      });
+
+      return () => import.meta.hot?.off('vite:afterUpdate', afterApdate);
+    }
+    return () => void 0;
+  };
+
+  const updateIsScrolling = () => (timelineManager.scrolling = true);
+  // note: don't throttle, debounch, or otherwise do this function async - it causes flicker
+  const updateSlidingWindow = () => timelineManager.updateSlidingWindow(element?.scrollTop || 0);
+
+  const handleScrollCompensation = ({ heightDelta, scrollTop }: { heightDelta?: number; scrollTop?: number }) => {
+    if (heightDelta !== undefined) {
+      scrollBy(heightDelta);
+    } else if (scrollTop !== undefined) {
+      scrollTo(scrollTop);
+    }
+    // Yes, updateSlideWindow() is called by the onScroll event triggered as a result of
+    // the above calls. However, this delay is enough time to set the intersecting property
+    // of the monthGroup to false, then true, which causes the DOM nodes to be recreated,
+    // causing bad perf, and also, disrupting focus of those elements.
+    updateSlidingWindow();
+  };
+
+  const topSectionResizeObserver: OnResizeCallback = ({ height }) => (timelineManager.topSectionHeight = height);
+
+  onMount(() => {
+    if (!enableRouting) {
+      showSkeleton = false;
+    }
+    const disposeHmr = hmrSupport();
+    return () => {
+      disposeHmr();
+    };
+  });
+
+  let onDateGroupSelect = <({ title, assets }: { title: string; assets: TimelineAsset[] }) => void>$state();
+  let onSelectAssets = <(asset: TimelineAsset) => Promise<void>>$state();
+  let onSelectAssetCandidates = <(asset: TimelineAsset | null) => void>$state();
+</script>
+
+<AssetDateGroupActions
+  {timelineManager}
+  {assetInteraction}
+  handleScrollTop={scrollTop}
+  {onSelect}
+  bind:onDateGroupSelect
+  bind:onSelectAssets
+  bind:onSelectAssetCandidates
+></AssetDateGroupActions>
+
+<AssetGridActions {scrollToAsset} {timelineManager} {assetInteraction} bind:isShowDeleteConfirmation {onEscape}
+></AssetGridActions>
+
+{@render header?.(scrollTop)}
+
+<!-- Right margin MUST be equal to the width of scrubber -->
+<section
+  id="asset-grid"
+  class={['scrollbar-hidden h-full overflow-y-auto outline-none', { 'm-0': isEmpty }, { 'ms-0': !isEmpty }]}
+  style:margin-right={(usingMobileDevice ? 0 : scrubberWidth) + 'px'}
+  tabindex="-1"
+  bind:clientHeight={timelineManager.viewportHeight}
+  bind:clientWidth={null, (v) => ((timelineManager.viewportWidth = v), updateSlidingWindow())}
+  bind:this={element}
+  onscroll={() => (handleTimelineScroll(), updateSlidingWindow(), updateIsScrolling())}
+>
+  <section
+    bind:this={timelineElement}
+    id="virtual-timeline"
+    class:invisible={showSkeleton}
+    style:height={timelineManager.timelineHeight + 'px'}
+  >
+    <section
+      use:resizeObserver={topSectionResizeObserver}
+      class:invisible={showSkeleton}
+      style:position="absolute"
+      style:left="0"
+      style:right="0"
+    >
+      {@render children?.()}
+      {#if isEmpty}
+        <!-- (optional) empty placeholder -->
+        {@render empty?.()}
+      {/if}
+    </section>
+
+    {#each timelineManager.months as monthGroup (monthGroup.viewId)}
+      {@const display = monthGroup.intersecting}
+      {@const absoluteHeight = monthGroup.top}
+
+      {#if !monthGroup.isLoaded}
+        <div
+          style:height={monthGroup.height + 'px'}
+          style:position="absolute"
+          style:transform={`translate3d(0,${absoluteHeight}px,0)`}
+          style:width="100%"
+        >
+          <Skeleton
+            height={monthGroup.height - monthGroup.timelineManager.headerHeight}
+            title={monthGroup.monthGroupTitle}
+          />
+        </div>
+      {:else if display}
+        <div
+          class="month-group"
+          style:height={monthGroup.height + 'px'}
+          style:position="absolute"
+          style:transform={`translate3d(0,${absoluteHeight}px,0)`}
+          style:width="100%"
+        >
+          <AssetDateGroup
+            {withStacked}
+            {showArchiveIcon}
+            {assetInteraction}
+            {timelineManager}
+            {isSelectionMode}
+            {singleSelect}
+            {monthGroup}
+            onSelect={onDateGroupSelect}
+            {onSelectAssetCandidates}
+            {onSelectAssets}
+            onScrollCompensation={handleScrollCompensation}
+          />
+        </div>
+      {/if}
+    {/each}
+    <!-- spacer for leadout -->
+    <div
+      class="h-[60px]"
+      style:position="absolute"
+      style:left="0"
+      style:right="0"
+      style:transform={`translate3d(0,${timelineManager.timelineHeight}px,0)`}
+    ></div>
+  </section>
+</section>
+
+<Portal target="body">
+  {#if $showAssetViewer}
+    <AssetViewerAndActions
+      bind:showSkeleton
+      {timelineManager}
+      {removeAction}
+      {withStacked}
+      {isShared}
+      {album}
+      {person}
+      {isShowDeleteConfirmation}
+    ></AssetViewerAndActions>
+  {/if}
+</Portal>
+
+<style>
+  #asset-grid {
+    contain: strict;
+    scrollbar-width: none;
+  }
+
+  .month-group {
+    contain: layout size paint;
+    transform-style: flat;
+    backface-visibility: hidden;
+    transform-origin: center center;
+  }
+</style>