fix(infra): compatibility fix for space prefix (#4912)

It seems there are some cases that [this upstream PR](https://github.com/toeverything/blocksuite/pull/4747) will cause data loss.

Because of some historical reasons, the page id could be different with its doc id.
It might be caused by subdoc migration in the following (not 100% sure if all white screen issue is caused by it) https://github.com/toeverything/AFFiNE/blob/0714c12703ff8840acc180633e5489c755ddfba3/packages/common/infra/src/blocksuite/index.ts#L538-L540

In version 0.10, page id in spaces no longer has prefix "space:"
The data flow for fetching a doc's updates is:
- page id in `meta.pages` -> find `${page-id}` in `doc.spaces` -> `doc` -> `doc.guid`
if `doc` is not found in `doc.spaces`, a new doc will be created and its `doc.guid` is the same with its pageId
- because of guid logic change, the doc that previously prefixed with `space:` will not be found in `doc.spaces`
- when fetching the rows of this doc using the doc id === page id,
  it will return EMPTY since there is no updates associated with the page id

The provided fix in the PR will patch the `spaces` field of the root doc so that after 0.10 the page doc can still be found in the `spaces` map. It shall apply to both of the idb & sqlite datasources.

Special thanks to @lawvs 's db file for investigation!

packages/frontend/hooks/src/__tests__/index.spec.ts

@@ -76,12 +76,25 @@ describe('useBlockSuitePagePreview', () => {
       page.getBlockByFlavour('affine:note')[0].id
     );
     const hook = renderHook(() => useAtomValue(useBlockSuitePagePreview(page)));
-    expect(hook.result.current).toBe('\nHello, world!');
+    expect(hook.result.current).toBe('Hello, world!');
     page.transact(() => {
       page.getBlockById(id)!.text!.insert('Test', 0);
     });
     await new Promise(resolve => setTimeout(resolve, 100));
     hook.rerender();
-    expect(hook.result.current).toBe('\nTestHello, world!');
+    expect(hook.result.current).toBe('TestHello, world!');
+
+    // Insert before
+    page.addBlock(
+      'affine:paragraph',
+      {
+        text: new page.Text('First block!'),
+      },
+      page.getBlockByFlavour('affine:note')[0].id,
+      0
+    );
+    await new Promise(resolve => setTimeout(resolve, 100));
+    hook.rerender();
+    expect(hook.result.current).toBe('First block! TestHello, world!');
   });
 });

packages/frontend/hooks/src/use-block-suite-page-preview.ts

@@ -1,20 +1,49 @@
-import type { ParagraphBlockModel } from '@blocksuite/blocks/models';
 import type { Page } from '@blocksuite/store';
 import type { Atom } from 'jotai';
 import { atom } from 'jotai';
 
+const MAX_PREVIEW_LENGTH = 150;
+const MAX_SEARCH_BLOCK_COUNT = 30;
+
 const weakMap = new WeakMap<Page, Atom<string>>();
 
 export const getPagePreviewText = (page: Page) => {
-  // TODO this is incorrect, since the order of blocks is not guaranteed
-  const paragraphBlocks = page.getBlockByFlavour(
-    'affine:paragraph'
-  ) as ParagraphBlockModel[];
-  const text = paragraphBlocks
-    .slice(0, 10)
-    .map(block => block.text.toString())
-    .join('\n');
-  return text.slice(0, 300);
+  const pageRoot = page.root;
+  if (!pageRoot) {
+    return '';
+  }
+  const preview: string[] = [];
+  // DFS
+  const queue = [pageRoot];
+  let previewLenNeeded = MAX_PREVIEW_LENGTH;
+  let count = MAX_SEARCH_BLOCK_COUNT;
+  while (queue.length && previewLenNeeded > 0 && count-- > 0) {
+    const block = queue.shift();
+    if (!block) {
+      console.error('Unexpected empty block');
+      break;
+    }
+    if (block.children) {
+      queue.unshift(...block.children);
+    }
+    if (block.role !== 'content') {
+      continue;
+    }
+    if (block.text) {
+      const text = block.text.toString();
+      if (!text.length) {
+        continue;
+      }
+      previewLenNeeded -= text.length;
+      preview.push(text);
+    } else {
+      // image/attachment/bookmark
+      const type = block.flavour.split('affine:')[1] ?? null;
+      previewLenNeeded -= type.length + 2;
+      type && preview.push(`[${type}]`);
+    }
+  }
+  return preview.join(' ');
 };
 
 const emptyAtom = atom<string>('');

packages/frontend/hooks/src/use-block-suite-workspace-page.ts

@@ -85,7 +85,7 @@ export function loadPage(page: Page, priority = 0) {
         logger.debug('page loaded', page.id);
         // we do not know how long it takes to load a page here
         // so that we just use 300ms timeout as the default page processing time
-        await awaitForTimeout(1000);
+        await awaitForTimeout(300);
       } else {
         // do nothing if it is already loaded
       }