AFFiNE-Mirror/blocksuite/affine/shared/src/utils/virtual-padding.ts

import type { BlockComponent } from '@blocksuite/block-std';
import { autoUpdate } from '@floating-ui/dom';
import { signal } from '@preact/signals-core';
import type { ReactiveController } from 'lit';

import { DocModeProvider } from '../services/doc-mode-service';

export class VirtualPaddingController implements ReactiveController {
  public readonly virtualPadding$ = signal(0);
  constructor(private readonly block: BlockComponent) {
    block.addController(this);
  }

  get std() {
    return this.host.std;
  }

  get host() {
    return this.block.host;
  }

  hostConnected(): void {
    if (this.std.get(DocModeProvider).getEditorMode() === 'edgeless') {
      return;
    }
    this.block.disposables.add(
      autoUpdate(this.host, this.block, () => {
        const padding =
          this.block.getBoundingClientRect().left -
          this.host.getBoundingClientRect().left;
        this.virtualPadding$.value = Math.max(0, padding - 72);
      })
    );
  }
}