feat(ocr): enhance Tesseract service with language support and worker management

- Added support for multiple Tesseract languages: Chinese (Simplified and Traditional) and English.
- Refactored Tesseract worker management into a class for better encapsulation and reuse.
- Introduced methods to dynamically determine language path based on IP country and manage worker lifecycle.

packages/shared/config/constant.ts

@@ -197,6 +197,12 @@ export enum FeedUrl {
   GITHUB_LATEST = 'https://github.com/CherryHQ/cherry-studio/releases/latest/download'
 }
 
+export const tesseractLangs = ['chi_sim', 'chi_tra', 'eng']
+export enum TesseractLangsDownloadUrl {
+  CN = 'https://gitcode.com/tesseract-ocr/tessdata/raw/main/',
+  GLOBAL = 'https://github.com/tesseract-ocr/tessdata/raw/main/'
+}
+
 export enum UpgradeChannel {
   LATEST = 'latest', // 最新稳定版本
   RC = 'rc', // 公测版本

src/main/services/ocr/OcrService.ts

@@ -13,7 +13,7 @@ import {
 import { statSync } from 'fs'
 import { readFile } from 'fs/promises'
 
-import { getTesseractWorker } from './tesseract/TesseractService'
+import { tesseractService } from './tesseract/TesseractService'
 
 const logger = loggerService.withContext('main:OcrService')
 
@@ -25,7 +25,7 @@ const logger = loggerService.withContext('main:OcrService')
  */
 const tesseractOcr = async (file: ImageFileMetadata | string): Promise<Tesseract.RecognizeResult> => {
   try {
-    const worker = await getTesseractWorker()
+    const worker = await tesseractService.getWorker()
     let ret: Tesseract.RecognizeResult
     if (typeof file === 'string') {
       ret = await worker.recognize(file)

src/main/services/ocr/tesseract/TesseractService.ts

@@ -1,10 +1,12 @@
 import { loggerService } from '@logger'
+import { getIpCountry } from '@main/utils/ipService'
+import { TesseractLangsDownloadUrl } from '@shared/config/constant'
+import { app } from 'electron'
+import path from 'path'
 import Tesseract, { createWorker } from 'tesseract.js'
 
 const logger = loggerService.withContext('TesseractService')
 
-let worker: Tesseract.Worker | null = null
-
 // const languageCodeMap: Record<string, string> = {
 //   'af-za': 'afr',
 //   'am-et': 'amh',
@@ -110,20 +112,36 @@ let worker: Tesseract.Worker | null = null
 //   'yi-us': 'yid'
 // }
 
-export const getTesseractWorker = async (): Promise<Tesseract.Worker> => {
-  if (!worker) {
-    // for now, only support limited languages
-    worker = await createWorker(['chi_sim', 'chi_tra', 'eng'], undefined, {
-      // langPath: getCacheDir(),
-      logger: (m) => logger.debug('From worker', m)
-    })
+export class TesseractService {
+  private worker: Tesseract.Worker | null = null
+
+  async getWorker(): Promise<Tesseract.Worker> {
+    if (!this.worker) {
+      // for now, only support limited languages
+      this.worker = await createWorker(['chi_sim', 'chi_tra', 'eng'], undefined, {
+        langPath: await this._getLangPath(),
+        cachePath: this._getCacheDir(),
+        logger: (m) => logger.debug('From worker', m)
+      })
+    }
+    return this.worker
+  }
+
+  private async _getLangPath(): Promise<string> {
+    const country = await getIpCountry()
+    return country.toLowerCase() === 'cn' ? TesseractLangsDownloadUrl.CN : TesseractLangsDownloadUrl.GLOBAL
+  }
+
+  private _getCacheDir(): string {
+    return path.join(app.getPath('userData'), 'tesseract')
+  }
+
+  async dispose(): Promise<void> {
+    if (this.worker) {
+      await this.worker.terminate()
+      this.worker = null
+    }
   }
-  return worker
 }
 
-export const disposeTesseractWorker = async () => {
-  if (worker) {
-    await worker.terminate()
-    worker = null
-  }
-}
+export const tesseractService = new TesseractService()