fix(blocks): only split paragraphs based on newlines

packages/blocks/src/_common/adapters/markdown.ts

@@ -1313,10 +1313,10 @@ export class MarkdownAdapter extends BaseAdapter<Markdown> {
         displayMode: NoteDisplayMode.DocAndEdgeless,
       },
       children: [],
-    };
+    } as BlockSnapshot;
     const contentSlice = (await this._traverseMarkdown(
       markdownAst,
-      blockSnapshotRoot as BlockSnapshot,
+      blockSnapshotRoot,
       payload.assets
     )) as BlockSnapshot;
     if (contentSlice.children.length === 0) {

packages/blocks/src/_common/adapters/mix-text.ts

@@ -46,6 +46,30 @@ export class MixTextAdapter extends BaseAdapter<MixText> {
     this._markdownAdapter = new MarkdownAdapter(job);
   }
 
+  private _splitDeltas(deltas: DeltaInsert[]): DeltaInsert[][] {
+    const result: DeltaInsert[][] = [[]];
+    const pending: DeltaInsert[] = deltas;
+    while (pending.length > 0) {
+      const delta = pending.shift();
+      if (!delta) {
+        break;
+      }
+      if (delta.insert.includes('\n')) {
+        const splitIndex = delta.insert.indexOf('\n');
+        const line = delta.insert.slice(0, splitIndex);
+        const rest = delta.insert.slice(splitIndex + 1);
+        result[result.length - 1].push({ ...delta, insert: line });
+        result.push([]);
+        if (rest) {
+          pending.unshift({ ...delta, insert: rest });
+        }
+      } else {
+        result[result.length - 1].push(delta);
+      }
+    }
+    return result;
+  }
+
   private async _traverseSnapshot(
     snapshot: BlockSnapshot
   ): Promise<{ mixtext: string }> {
@@ -245,13 +269,6 @@ export class MixTextAdapter extends BaseAdapter<MixText> {
       return null;
     }
     payload.file = payload.file.replaceAll('\r', '');
-    const lines = payload.file.split('\n');
-    for (let i = 0; i < lines.length - 1; i++) {
-      if (lines[i].length !== 0 && lines[i + 1].length !== 0) {
-        lines[i] += '\n';
-      }
-    }
-    payload.file = lines.join('\n');
     const sliceSnapshot = await this._markdownAdapter.toSliceSnapshot({
       file: payload.file,
       assets: payload.assets,
@@ -260,6 +277,79 @@ export class MixTextAdapter extends BaseAdapter<MixText> {
       workspaceId: payload.workspaceId,
       pageId: payload.pageId,
     });
+    if (!sliceSnapshot) {
+      return null;
+    }
+    for (const contentSlice of sliceSnapshot.content) {
+      const blockSnapshotRoot = {
+        type: 'block',
+        id: nanoid(),
+        flavour: 'affine:note',
+        props: {
+          xywh: '[0,0,800,95]',
+          background: DEFAULT_NOTE_BACKGROUND_COLOR,
+          index: 'a0',
+          hidden: false,
+          displayMode: NoteDisplayMode.DocAndEdgeless,
+        },
+        children: [],
+      } as BlockSnapshot;
+      const walker = new ASTWalker<BlockSnapshot, BlockSnapshot>();
+      walker.setONodeTypeGuard(
+        (node): node is BlockSnapshot =>
+          BlockSnapshotSchema.safeParse(node).success
+      );
+      walker.setEnter((o, context) => {
+        switch (o.node.flavour) {
+          case 'affine:note': {
+            break;
+          }
+          case 'affine:paragraph': {
+            if (o.parent?.node.flavour !== 'affine:note') {
+              context.openNode({ ...o.node, children: [] });
+              break;
+            }
+            const text = (o.node.props.text ?? { delta: [] }) as {
+              delta: DeltaInsert[];
+            };
+            const newDeltas = this._splitDeltas(text.delta);
+            for (const [i, delta] of newDeltas.entries()) {
+              context.openNode({
+                ...o.node,
+                id: i === 0 ? o.node.id : nanoid(),
+                props: {
+                  ...o.node.props,
+                  text: {
+                    '$blocksuite:internal:text$': true,
+                    delta,
+                  },
+                },
+                children: [],
+              });
+              if (i < newDeltas.length - 1) {
+                context.closeNode();
+              }
+            }
+            break;
+          }
+          default: {
+            context.openNode({ ...o.node, children: [] });
+          }
+        }
+      });
+      walker.setLeave((o, context) => {
+        switch (o.node.flavour) {
+          case 'affine:note': {
+            break;
+          }
+          default: {
+            context.closeNode();
+          }
+        }
+      });
+      await walker.walk(contentSlice, blockSnapshotRoot);
+      contentSlice.children = blockSnapshotRoot.children;
+    }
     return sliceSnapshot;
   }
 }