feat: use native preview for pdf in mobile webview (#1728)

packages/web/src/javascripts/Components/FilePreview/FilePreview.tsx

@@ -66,7 +66,7 @@ const FilePreview = ({ file, application }: Props) => {
       <span className="mt-3">Loading file...</span>
     </div>
   ) : downloadedBytes ? (
-    <PreviewComponent file={file} bytes={downloadedBytes} />
+    <PreviewComponent application={application} file={file} bytes={downloadedBytes} />
   ) : (
     <FilePreviewError
       file={file}

packages/web/src/javascripts/Components/FilePreview/PreviewComponent.tsx

@@ -1,16 +1,24 @@
+import { WebApplication } from '@/Application/Application'
+import { getBase64FromBlob } from '@/Utils'
 import { FileItem } from '@standardnotes/snjs'
-import { FunctionComponent, useEffect, useMemo, useRef } from 'react'
+import { FunctionComponent, useCallback, useEffect, useMemo, useRef } from 'react'
+import Button from '../Button/Button'
+import { AppPaneId } from '../ResponsivePane/AppPaneMetadata'
+import { useResponsiveAppPane } from '../ResponsivePane/ResponsivePaneProvider'
 import { createObjectURLWithRef } from './CreateObjectURLWithRef'
 import ImagePreview from './ImagePreview'
-import { PreviewableTextFileTypes } from './isFilePreviewable'
+import { PreviewableTextFileTypes, RequiresNativeFilePreview } from './isFilePreviewable'
 import TextPreview from './TextPreview'
 
 type Props = {
+  application: WebApplication
   file: FileItem
   bytes: Uint8Array
 }
 
-const PreviewComponent: FunctionComponent<Props> = ({ file, bytes }) => {
+const PreviewComponent: FunctionComponent<Props> = ({ application, file, bytes }) => {
+  const { selectedPane } = useResponsiveAppPane()
+
   const objectUrlRef = useRef<string>()
 
   const objectUrl = useMemo(() => {
@@ -28,6 +36,42 @@ const PreviewComponent: FunctionComponent<Props> = ({ file, bytes }) => {
     }
   }, [])
 
+  const isNativeMobileWeb = application.isNativeMobileWeb()
+  const requiresNativePreview = RequiresNativeFilePreview.includes(file.mimeType)
+
+  const openNativeFilePreview = useCallback(async () => {
+    if (!isNativeMobileWeb) {
+      throw new Error('Native file preview cannot be used on non-native platform')
+    }
+
+    const fileBase64 = await getBase64FromBlob(
+      new Blob([bytes], {
+        type: file.mimeType,
+      }),
+    )
+
+    application.mobileDevice().previewFile(fileBase64, file.name)
+  }, [application, bytes, file.mimeType, file.name, isNativeMobileWeb])
+
+  useEffect(() => {
+    const shouldOpenNativePreviewOnLoad =
+      isNativeMobileWeb && selectedPane === AppPaneId.Editor && requiresNativePreview
+    if (shouldOpenNativePreviewOnLoad) {
+      void openNativeFilePreview()
+    }
+  }, [isNativeMobileWeb, openNativeFilePreview, requiresNativePreview, selectedPane])
+
+  if (isNativeMobileWeb && requiresNativePreview) {
+    return (
+      <div className="flex flex-grow flex-col items-center justify-center">
+        <div className="text-base font-bold">Previewing file...</div>
+        <Button className="mt-3" primary onClick={openNativeFilePreview}>
+          Re-open file preview
+        </Button>
+      </div>
+    )
+  }
+
   if (file.mimeType.startsWith('image/')) {
     return <ImagePreview objectUrl={objectUrl} />
   }

packages/web/src/javascripts/Components/FilePreview/isFilePreviewable.ts

@@ -1,5 +1,7 @@
 export const PreviewableTextFileTypes = ['text/plain', 'text/csv', 'application/json']
 
+export const RequiresNativeFilePreview = ['application/pdf']
+
 export const isFileTypePreviewable = (fileType: string) => {
   const isImage = fileType.startsWith('image/')
   const isVideo = fileType.startsWith('video/')