fix(frontend): emptied chat keeps its storage head, shared-only chat explains why nothing can be bulk moved, back from a chat returns to the same place in the list, cleanup wording agrees in number

frontend/src/lib/components/disk/StoragePanel.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-  import { onDestroy, onMount } from "svelte";
+  import { onDestroy, onMount, tick } from "svelte";
   import { SvelteSet } from "svelte/reactivity";
   import { mediaUrl } from "#lib/api/client.js";
   import { downloadMedia } from "#lib/api/download.js";
@@ -61,7 +61,7 @@
   let summary = $state<StorageSummary | null>(null);
   let files = $state<StorageFile[]>([]);
   let heavyChats = $state<StorageChat[]>([]);
-  let scopeRevision = $state(0);
+  let scope = $state<ReturnType<typeof ScopeFiles>>();
   let group = $state<StorageGroupName | null>(null);
   let loading = $state(false);
   let failed = $state(false);
@@ -75,6 +75,7 @@
   let viewerIndex = $state(0);
   const selected = new SvelteSet<number>();
   let token = 0;
+  let scroller: HTMLElement | null = null;
   let undoTimer: ReturnType<typeof setTimeout> | undefined;
   let undoShownAt = 0;
 
@@ -130,10 +131,10 @@
     }
   }
 
-  async function loadPage(current: number): Promise<number> {
+  async function loadPage(current: number, limit: number): Promise<number> {
     if (listing === "chats") {
       const batch = await getStorageChats(group, {
-        limit: PAGE,
+        limit,
         offset: heavyChats.length,
       });
       if (current === token) {
@@ -144,7 +145,7 @@
     }
     const batch = await getStorageFiles(
       group,
-      { limit: PAGE, offset: files.length },
+      { limit, offset: files.length },
       chatId
     );
     if (current === token) {
@@ -154,7 +155,7 @@
     return batch.length;
   }
 
-  async function loadMore() {
+  async function loadMore(limit = PAGE) {
     if (loading || done) {
       return;
     }
@@ -162,9 +163,9 @@
     loading = true;
     failed = false;
     try {
-      const loaded = await loadPage(current);
+      const loaded = await loadPage(current, limit);
       if (current === token) {
-        done = loaded < PAGE;
+        done = loaded < limit;
       }
     } catch {
       if (current === token) {
@@ -177,15 +178,34 @@
     }
   }
 
-  function reload() {
+  function reload(limit = PAGE) {
     token += 1;
     files = [];
     heavyChats = [];
     done = false;
     loading = false;
     selected.clear();
-    loadSummary();
-    loadMore();
+    return Promise.all([loadSummary(), loadMore(limit)]);
+  }
+
+  async function resume() {
+    const from = chatId === null ? storageUi.takeResume() : null;
+    await reload(Math.ceil(Math.max(1, from?.count ?? 0) / PAGE) * PAGE);
+    if (from && scroller) {
+      await tick();
+      scroller.scrollTop = from.top;
+    }
+  }
+
+  function openChat(id: number) {
+    storageUi.openChat(id, {
+      count: heavyChats.length,
+      top: scroller?.scrollTop ?? 0,
+    });
+  }
+
+  function hold(node: HTMLElement) {
+    scroller = node.parentElement;
   }
 
   function toggle(mediaId: number) {
@@ -226,7 +246,7 @@
       }
       files = files.filter((file) => !moved.has(file.media_id));
       selected.clear();
-      scopeRevision += 1;
+      scope?.refresh();
       showUndo(outcome, trashed);
       if (outcome.blocked.length > 0) {
         problem = "Файл занят в сторис или аватаре и остался на диске";
@@ -250,7 +270,7 @@
       files = [...files, ...restored.files].sort(
         (a, b) => b.file_size - a.file_size
       );
-      scopeRevision += 1;
+      scope?.refresh();
       await loadSummary();
     } catch {
       problem = "Не удалось вернуть файлы";
@@ -301,16 +321,16 @@
     }
   }
 
-  onMount(reload);
+  onMount(resume);
   onDestroy(() => clearTimeout(undoTimer));
 </script>
 
-<div class="storage">
+<div class="storage" {@attach hold}>
   {#if summary}
-    {#if summary.files > 0}
+    {#if summary.files > 0 || chatId !== null}
       <section class="summary">
         <div class="hero">
-          <span class="total">{formatBytes(summary.bytes)}</span>
+          <span class="total">{formatBytes(summary.bytes) || "0 B"}</span>
           <span class="count">
             {filesLabel(summary.files)}
             {#if chatId !== null}
@@ -322,7 +342,7 @@
             {/if}
           </span>
         </div>
-        <div class="stack">
+        <div class="stack" class:bare={groups.length === 0}>
           {#each groups as item (item.group)}
             <span
               title="{GROUP_LABELS[item.group]}: {formatBytes(item.bytes)}"
@@ -392,16 +412,15 @@
         {/each}
       </div>
     {:else}
-      {#key scopeRevision}
-        <ScopeFiles
-          label="Все файлы чата"
-          onchange={() => {
-            hideUndo();
-            reload();
-          }}
-          target={{ chatId }}
-        />
-      {/key}
+      <ScopeFiles
+        label="Все файлы чата"
+        onchange={() => {
+          hideUndo();
+          reload();
+        }}
+        target={{ chatId }}
+        bind:this={scope}
+      />
     {/if}
   {/if}
 
@@ -423,15 +442,12 @@
       <StorageChatRow
         {chat}
         hasAvatar={chats.byId(chat.chat_id)?.has_avatar ?? false}
-        onopen={() => storageUi.openChat(chat.chat_id)}
+        onopen={() => openChat(chat.chat_id)}
         title={chatTitle(chat.chat_id)}
         weight={heaviestChat > 0 ? chat.bytes / heaviestChat : 0}
       >
         {#snippet menu()}
-          <ContextMenuItem
-            icon="data"
-            onselect={() => storageUi.openChat(chat.chat_id)}
-          >
+          <ContextMenuItem icon="data" onselect={() => openChat(chat.chat_id)}>
             Файлы чата
           </ContextMenuItem>
           <ContextMenuItem icon="reply" onselect={() => visit(chat)}>
@@ -491,12 +507,14 @@
     {:else if failed}
       <div class="state">
         <p>Не удалось загрузить хранилище.</p>
-        <Button onclick={reload} smaller variant="text">Повторить</Button>
+        <Button onclick={() => reload()} smaller variant="text">
+          Повторить
+        </Button>
       </div>
     {:else if shown === 0}
       <div class="state"><p>{emptiness}</p></div>
     {:else if !done}
-      <button class="more" onclick={loadMore} type="button">
+      <button class="more" onclick={() => loadMore()} type="button">
         Показать ещё
       </button>
     {/if}
@@ -599,6 +617,11 @@
     height: 0.625rem;
     margin-top: 0.875rem;
 
+    &.bare {
+      border-radius: 0.3125rem;
+      background-color: rgba(var(--color-text-secondary-rgb), 0.16);
+    }
+
     span {
       min-width: 0.1875rem;
       border-radius: 2px;