fix(editor): prevent SwiftKey IME double input (#13590)

Close
[BS-3610](https://linear.app/affine-design/issue/BS-3610/bug-每次按空格会出现重复单词-，特定输入法，比如swiftkey)

#### PR Dependency Tree

* **PR #13591**
  * **PR #13590** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- Bug Fixes
- Android: More reliable Backspace/delete handling, preventing missed
inputs and double-deletions.
- Android: Cursor/selection is correctly restored after merging a
paragraph with the previous block.
- Android: Smoother IME composition input; captures correct composition
range.
- Deletion across lines and around embeds/empty lines is more
consistent.
- Chores
- Internal event handling updated to improve Android compatibility and
stability (no user-facing changes).
<!-- end of auto-generated comment: release notes by coderabbit.ai -->





#### PR Dependency Tree


* **PR #13591**
  * **PR #13590** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

blocksuite/affine/blocks/paragraph/src/utils/merge-with-prev.ts

@@ -24,7 +24,7 @@ import {
   getPrevContentBlock,
   matchModels,
 } from '@blocksuite/affine-shared/utils';
-import { IS_MOBILE } from '@blocksuite/global/env';
+import { IS_ANDROID, IS_MOBILE } from '@blocksuite/global/env';
 import { BlockSelection, type EditorHost } from '@blocksuite/std';
 import type { BlockModel, Text } from '@blocksuite/store';
 
@@ -79,6 +79,28 @@ export function mergeWithPrev(editorHost: EditorHost, model: BlockModel) {
       index: lengthBeforeJoin,
       length: 0,
     }).catch(console.error);
+
+    // due to some IME like Microsoft Swift IME on Android will reset range after join text,
+    // for example:
+    //
+    // $ZERO_WIDTH_FOR_EMPTY_LINE     <--- p1
+    // |aaa                           <--- p2
+    //
+    // after pressing backspace, during beforeinput event, the native range is (p1, 1) -> (p2, 0)
+    // and after browser and IME handle the event, the native range is (p1, 1) -> (p1, 1)
+    //
+    // a|aa                            <--- p1
+    //
+    // so we need to set range again after join text.
+    if (IS_ANDROID) {
+      setTimeout(() => {
+        asyncSetInlineRange(editorHost.std, prevBlock, {
+          index: lengthBeforeJoin,
+          length: 0,
+        }).catch(console.error);
+      });
+    }
+
     return true;
   }
 

blocksuite/framework/std/src/event/control/keyboard.ts

@@ -1,4 +1,5 @@
-import { IS_MAC } from '@blocksuite/global/env';
+import { DisposableGroup } from '@blocksuite/global/disposable';
+import { IS_ANDROID, IS_MAC } from '@blocksuite/global/env';
 
 import {
   type UIEventHandler,
@@ -6,7 +7,7 @@ import {
   UIEventStateContext,
 } from '../base.js';
 import type { EventOptions, UIEventDispatcher } from '../dispatcher.js';
-import { bindKeymap } from '../keymap.js';
+import { androidBindKeymapPatch, bindKeymap } from '../keymap.js';
 import { KeyboardEventState } from '../state/index.js';
 import { EventScopeSourceType, EventSourceState } from '../state/source.js';
 
@@ -87,15 +88,29 @@ export class KeyboardControl {
   }
 
   bindHotkey(keymap: Record<string, UIEventHandler>, options?: EventOptions) {
-    return this._dispatcher.add(
+    const disposables = new DisposableGroup();
-      'keyDown',
+    if (IS_ANDROID) {
-      ctx => {
+      disposables.add(
-        if (this.composition) return false;
+        this._dispatcher.add('beforeInput', ctx => {
-        const binding = bindKeymap(keymap);
+          if (this.composition) return false;
-        return binding(ctx);
+          const binding = androidBindKeymapPatch(keymap);
-      },
+          return binding(ctx);
-      options
+        })
+      );
+    }
+
+    disposables.add(
+      this._dispatcher.add(
+        'keyDown',
+        ctx => {
+          if (this.composition) return false;
+          const binding = bindKeymap(keymap);
+          return binding(ctx);
+        },
+        options
+      )
     );
+    return () => disposables.dispose();
   }
 
   listen() {

blocksuite/framework/std/src/event/keymap.ts

@@ -103,3 +103,25 @@ export function bindKeymap(
     return false;
   };
 }
+
+// In some IME of Android like, the keypress event  dose not contain
+// the information about what key is pressed. See
+// https://stackoverflow.com/a/68188679
+// https://stackoverflow.com/a/66724830
+export function androidBindKeymapPatch(
+  bindings: Record<string, UIEventHandler>
+): UIEventHandler {
+  return ctx => {
+    const event = ctx.get('defaultState').event;
+    if (!(event instanceof InputEvent)) return;
+
+    if (
+      event.inputType === 'deleteContentBackward' &&
+      'Backspace' in bindings
+    ) {
+      return bindings['Backspace'](ctx);
+    }
+
+    return false;
+  };
+}

blocksuite/framework/std/src/inline/services/event.ts

@@ -1,3 +1,4 @@
+import { IS_ANDROID } from '@blocksuite/global/env';
 import type { BaseTextAttributes } from '@blocksuite/store';
 
 import type { InlineEditor } from '../inline-editor.js';
@@ -41,11 +42,10 @@ export class EventService<TextAttributes extends BaseTextAttributes> {
     }
   };
 
-  private readonly _onBeforeInput = (event: InputEvent) => {
+  private readonly _onBeforeInput = async (event: InputEvent) => {
     const range = this.editor.rangeService.getNativeRange();
     if (
       this.editor.isReadonly ||
-      this._isComposing ||
       !range ||
       !this._isRangeCompletelyInRoot(range)
     )
@@ -54,33 +54,29 @@ export class EventService<TextAttributes extends BaseTextAttributes> {
     let inlineRange = this.editor.toInlineRange(range);
     if (!inlineRange) return;
 
+    if (this._isComposing) {
+      if (IS_ANDROID && event.inputType === 'insertCompositionText') {
+        this._compositionInlineRange = inlineRange;
+      }
+      return;
+    }
+
     let ifHandleTargetRange = true;
 
-    if (event.inputType.startsWith('delete')) {
+    if (
-      if (
+      event.inputType.startsWith('delete') &&
-        isInEmbedGap(range.commonAncestorContainer) &&
+      (isInEmbedGap(range.commonAncestorContainer) ||
-        inlineRange.length === 0 &&
-        inlineRange.index > 0
-      ) {
-        inlineRange = {
-          index: inlineRange.index - 1,
-          length: 1,
-        };
-        ifHandleTargetRange = false;
-      } else if (
-        isInEmptyLine(range.commonAncestorContainer) &&
-        inlineRange.length === 0 &&
-        inlineRange.index > 0
-        // eslint-disable-next-line sonarjs/no-duplicated-branches
-      ) {
-        // do not use target range when deleting across lines
         // https://github.com/toeverything/blocksuite/issues/5381
-        inlineRange = {
+        isInEmptyLine(range.commonAncestorContainer)) &&
-          index: inlineRange.index - 1,
+      inlineRange.length === 0 &&
-          length: 1,
+      inlineRange.index > 0
-        };
+    ) {
-        ifHandleTargetRange = false;
+      // do not use target range when deleting across lines
-      }
+      inlineRange = {
+        index: inlineRange.index - 1,
+        length: 1,
+      };
+      ifHandleTargetRange = false;
     }
 
     if (ifHandleTargetRange) {
@@ -97,11 +93,24 @@ export class EventService<TextAttributes extends BaseTextAttributes> {
         }
       }
     }
-
     if (!inlineRange) return;
 
     event.preventDefault();
 
+    if (IS_ANDROID) {
+      this.editor.rerenderWholeEditor();
+      await this.editor.waitForUpdate();
+      if (
+        event.inputType === 'deleteContentBackward' &&
+        !(inlineRange.index === 0 && inlineRange.length === 0)
+      ) {
+        // when press backspace at offset 1, double characters will be removed.
+        // because we mock backspace key event `androidBindKeymapPatch` in blocksuite/framework/std/src/event/keymap.ts
+        // so we need to stop the event propagation to prevent the double characters removal.
+        event.stopPropagation();
+      }
+    }
+
     const ctx: BeforeinputHookCtx<TextAttributes> = {
       inlineEditor: this.editor,
       raw: event,
@@ -346,11 +355,9 @@ export class EventService<TextAttributes extends BaseTextAttributes> {
       return;
     }
 
-    this.editor.disposables.addFromEvent(
+    this.editor.disposables.addFromEvent(eventSource, 'beforeinput', e => {
-      eventSource,
+      this._onBeforeInput(e).catch(console.error);
-      'beforeinput',
+    });
-      this._onBeforeInput
-    );
     this.editor.disposables.addFromEvent(
       eventSource,
       'compositionstart',