修复bug，第一次导出缩略图，后面有了高清图后再次导出应该覆盖

按原图、中图和缩略图对本地图片资源分级，始终优先选择高清变体。

增量导出仅复用满足清晰度要求的图片，重新探测旧缩略图并在高清图出现后替换；仅缩略图降级时显示提示。

src/main/export-service.ts

@@ -23,6 +23,7 @@ import { getImageExportAttempts } from '../shared/export-media'
 import { FileAssetService } from './file-asset-service'
 import { mergeCachedSelfInfo } from './services/bootstrap-cache'
 import type { VoiceRecognitionUseCase } from './voice-pipeline/voice-recognition-use-case'
+import { imageFileQuality } from '../shared/image-quality'
 
 const jobs = new Set<string>()
 const activeArchives = new Map<string, Archiver>()
@@ -250,6 +251,7 @@ const mergeArchiveMessage = (previous: Message, current: Message): Message => {
     'exportMediaUrl',
     'exportMediaType',
     'exportMediaName',
+    'exportMediaQuality',
     'exportAvatarUrl'
   ]
   for (const key of preserveWhenMissing) {
@@ -706,6 +708,7 @@ export async function runExport(
       message.exportMediaUrl = undefined
       message.exportMediaType = undefined
       message.exportMediaName = undefined
+      message.exportMediaQuality = undefined
       message.exportMediaError = undefined
       message.voiceDataUrl = undefined
       message.voiceTranscript = undefined
@@ -1063,15 +1066,20 @@ export async function runExport(
             : message.contentData.type === 'share' && message.contentData.typeVal === '6'
               ? 'file'
               : null
+        const reusableImageQuality =
+          previous?.exportMediaQuality === 'original' ||
+          (request.preferOriginal === false && previous?.exportMediaQuality === 'thumbnail')
         if (
           reusableMediaType &&
           previous?.exportMediaUrl &&
           (!previous.exportMediaType || previous.exportMediaType === reusableMediaType) &&
+          (reusableMediaType !== 'image' || reusableImageQuality) &&
           (await resourceExists(previous.exportMediaUrl))
         ) {
           message.exportMediaUrl = previous.exportMediaUrl
           message.exportMediaType = reusableMediaType
           message.exportMediaName = previous.exportMediaName
+          message.exportMediaQuality = previous.exportMediaQuality
           send({
             jobId: request.jobId,
             phase: 'media',
@@ -1087,7 +1095,6 @@ export async function runExport(
           } else {
             let fileFound = false
             let decryptedImage: { data: string; filePath: string } | null = null
-            let usedFallback = false
             for (const attempt of getImageExportAttempts(request)) {
               const file = await imageService.findImageFileAsync(
                 message.contentData.md5,
@@ -1116,7 +1123,6 @@ export async function runExport(
               }
               if (!decrypted) continue
               decryptedImage = decrypted
-              usedFallback = attempt.fallback || imageService.isThumbnailFile(decrypted.filePath)
               break
             }
             const decoded = decryptedImage ? decodeDataUrl(decryptedImage.data) : null
@@ -1129,7 +1135,8 @@ export async function runExport(
               }
               message.exportMediaUrl = mediaUrl
               message.exportMediaType = 'image'
-              if (usedFallback) {
+              message.exportMediaQuality = imageFileQuality(decryptedImage!.filePath)
+              if (request.preferOriginal !== false && message.exportMediaQuality === 'thumbnail') {
                 keepMediaError(request, message, '原图不可用，已降级使用缩略图')
               }
             } else if (!fileFound) {

src/main/image-decrypt-service.ts

@@ -7,6 +7,7 @@ import { execFile } from 'child_process'
 import { Worker } from 'worker_threads'
 import ffmpegStaticPath from 'ffmpeg-static'
 import type { ImageDecoderSource, ImageDecoderStatus } from '../shared/image-decryption'
+import { imageFileQuality, imageQualityRank } from '../shared/image-quality'
 import { loadSettings } from './services/settings-store'
 import { Wcdb4Client } from './wcdb4-client'
 
@@ -208,6 +209,13 @@ function isThumbnailName(fileName) {
   return /(?:_t(?:_m)?|_thumb|\.thumb|_b|_w|_c)\.dat$/i.test(lower)
 }
 
+function imageQualityRank(fileName) {
+  const lower = fileName.toLowerCase()
+  if (/(?:_t(?:_m)?|_thumb|\.thumb|_b|_w|_c)\.dat$/i.test(lower)) return 1
+  if (/(?:_hd|\.hd|_h_m|_h|\.h)\.dat$/i.test(lower)) return 3
+  return 2
+}
+
 function buildPreferredDatNames(baseName) {
   const base = normalizeDatBase(baseName)
   if (!base) return []
@@ -436,8 +444,8 @@ function collectCandidates(datPath, allowThumbnail) {
     .map((name) => path.join(directory, name))
     .filter((candidate) => fs.existsSync(candidate))
     .sort((left, right) => {
-      const thumbnailOrder = Number(isThumbnailName(path.basename(left))) - Number(isThumbnailName(path.basename(right)))
-      return thumbnailOrder || fs.statSync(right).size - fs.statSync(left).size
+      const qualityOrder = imageQualityRank(path.basename(right)) - imageQualityRank(path.basename(left))
+      return qualityOrder || fs.statSync(right).size - fs.statSync(left).size
     })
   return Array.from(new Set(candidates.concat(siblings)))
 }
@@ -1824,17 +1832,17 @@ export class ImageDecryptService {
         .sort((left, right) => right.size - left.size)
 
     const thumbnail = toSized(
-      paths.filter((candidate) => this.isThumbnailName(basename(candidate)))
+      paths.filter((candidate) => imageFileQuality(candidate) === 'thumbnail')
     )
     if (preferThumbnail && thumbnail[0]) return thumbnail[0].candidate
-    const nonThumb = toSized(
-      paths.filter((candidate) => !this.isThumbnailName(basename(candidate)))
-    )
-    if (nonThumb[0]) return nonThumb[0].candidate
-    if (!allowThumbnail) return null
-
-    const existing = toSized(paths)
-    return existing[0]?.candidate || null
+    const allowed = toSized(paths)
+      .filter((entry) => allowThumbnail || imageFileQuality(entry.candidate) !== 'thumbnail')
+      .sort(
+        (left, right) =>
+          imageQualityRank(imageFileQuality(right.candidate)) -
+            imageQualityRank(imageFileQuality(left.candidate)) || right.size - left.size
+      )
+    return allowed[0]?.candidate || null
   }
 
   private async getLargestExistingPathAsync(
@@ -1858,17 +1866,21 @@ export class ImageDecryptService {
       .sort((left, right) => right.size - left.size)
 
     if (preferThumbnail) {
-      const thumbnail = sized.find((entry) => this.isThumbnailName(basename(entry.candidate)))
+      const thumbnail = sized.find((entry) => imageFileQuality(entry.candidate) === 'thumbnail')
       if (thumbnail) return thumbnail.candidate
     }
-    const nonThumbnail = sized.find((entry) => !this.isThumbnailName(basename(entry.candidate)))
-    if (nonThumbnail) return nonThumbnail.candidate
-    return allowThumbnail ? sized[0]?.candidate || null : null
+    const allowed = sized
+      .filter((entry) => allowThumbnail || imageFileQuality(entry.candidate) !== 'thumbnail')
+      .sort(
+        (left, right) =>
+          imageQualityRank(imageFileQuality(right.candidate)) -
+            imageQualityRank(imageFileQuality(left.candidate)) || right.size - left.size
+      )
+    return allowed[0]?.candidate || null
   }
 
   private isThumbnailName(fileName: string): boolean {
-    const lower = fileName.toLowerCase()
-    return /(?:_t(?:_m)?|_thumb|\.thumb|_b|_w|_c)\.dat$/i.test(lower)
+    return imageFileQuality(fileName) === 'thumbnail'
   }
 
   isThumbnailFile(filePath: string): boolean {

src/main/services/chat-service.ts

@@ -10,6 +10,7 @@ import type {
   DatabaseKeyValidationResult
 } from '../../shared/database-key'
 import { mergeRecallArchiveMessages, recordRecallArchiveMessages } from './recall-archive-service'
+import type { ExportImageQuality } from '../../shared/image-quality'
 
 export function getCurrentKey(): string {
   if (!dbRef) return ''
@@ -60,6 +61,7 @@ export interface FormattedMessage {
   exportMediaUrl?: string
   exportMediaType?: 'image' | 'video' | 'sticker' | 'file'
   exportMediaName?: string
+  exportMediaQuality?: ExportImageQuality
   exportShowAvatar?: boolean
   exportMediaError?: string
   exportAvatarUrl?: string

src/shared/export-media.ts

@@ -3,20 +3,17 @@ import type { ExportRequest } from './export'
 export type ImageExportAttempt = {
   allowThumbnail: boolean
   preferThumbnail: boolean
-  fallback: boolean
 }
 
 export function getImageExportAttempts(
   request: Pick<ExportRequest, 'preferOriginal' | 'fallbackThumbnail'>
 ): ImageExportAttempt[] {
   if (request.preferOriginal === false) {
-    return [{ allowThumbnail: true, preferThumbnail: true, fallback: false }]
+    return [{ allowThumbnail: true, preferThumbnail: true }]
   }
-  const attempts: ImageExportAttempt[] = [
-    { allowThumbnail: false, preferThumbnail: false, fallback: false }
-  ]
+  const attempts: ImageExportAttempt[] = [{ allowThumbnail: false, preferThumbnail: false }]
   if (request.fallbackThumbnail !== false) {
-    attempts.push({ allowThumbnail: true, preferThumbnail: true, fallback: true })
+    attempts.push({ allowThumbnail: true, preferThumbnail: true })
   }
   return attempts
 }

src/shared/image-quality.ts

@@ -0,0 +1,24 @@
+export type ExportImageQuality = 'original' | 'medium' | 'thumbnail'
+
+const fileNameOf = (filePath: string): string =>
+  String(filePath || '')
+    .trim()
+    .toLowerCase()
+    .split(/[\\/]/)
+    .pop() || ''
+
+export const imageFileQuality = (filePath: string): ExportImageQuality => {
+  const fileName = fileNameOf(filePath)
+  if (!fileName.endsWith('.dat')) return 'original'
+  if (/(?:_t(?:_m)?|_thumb|\.thumb|_b|_w|_c)\.dat$/i.test(fileName)) {
+    return 'thumbnail'
+  }
+  if (/(?:_hd|\.hd|_h_m|_h|\.h)\.dat$/i.test(fileName)) return 'original'
+  return 'medium'
+}
+
+export const imageQualityRank = (quality: ExportImageQuality): number => {
+  if (quality === 'original') return 3
+  if (quality === 'medium') return 2
+  return 1
+}

src/shared/types.ts

@@ -1,3 +1,5 @@
+import type { ExportImageQuality } from './image-quality'
+
 export interface Contact {
   m_nsUsrName: string
   m_nsNickName: string
@@ -36,6 +38,7 @@ export interface Message {
   exportMediaUrl?: string
   exportMediaType?: 'image' | 'video' | 'sticker' | 'file'
   exportMediaName?: string
+  exportMediaQuality?: ExportImageQuality
   exportShowAvatar?: boolean
   exportMediaError?: string
   exportAvatarUrl?: string