fix: 416 HTTP error deleting local files fix (#2139)

src/main/services/download/js-http-downloader.ts

@@ -346,6 +346,17 @@ export class JsHttpDownloader {
     }
   }
 
+  private parseTotalSizeFrom416(response: Response): number | null {
+    const contentRange = response.headers.get("content-range");
+    if (!contentRange) return null;
+
+    const match = /bytes\s+\*\/(\d+)/i.exec(contentRange);
+    if (!match) return null;
+
+    const total = Number.parseInt(match[1], 10);
+    return Number.isFinite(total) && total > 0 ? total : null;
+  }
+
   private async executeDownload(
     url: string,
     requestHeaders: Record<string, string>,
@@ -366,25 +377,23 @@ export class JsHttpDownloader {
     );
 
     if (response.status === 416 && startByte > 0) {
-      logger.log(
-        "[JsHttpDownloader] Range not satisfiable, deleting existing file and restarting"
-      );
-      if (fs.existsSync(filePath)) {
-        fs.unlinkSync(filePath);
+      const remoteTotalSize = this.parseTotalSizeFrom416(response);
+
+      if (remoteTotalSize !== null && startByte === remoteTotalSize) {
+        this.fileSize = remoteTotalSize;
+        this.bytesDownloaded = remoteTotalSize;
+        this.status = "complete";
+        this.retryCount = 0;
+        this.downloadSpeed = 0;
+
+        logger.log(
+          "[JsHttpDownloader] Range not satisfiable but local file already complete"
+        );
+        return;
       }
-      this.bytesDownloaded = 0;
-      this.resetSpeedTracking();
 
-      const headersWithoutRange = { ...requestHeaders };
-      delete headersWithoutRange["Range"];
-
-      return this.executeDownload(
-        url,
-        headersWithoutRange,
-        filePath,
-        0,
-        savePath,
-        usedFallback
+      throw new Error(
+        `[JsHttpDownloader] Range not satisfiable for resumed download (local=${startByte}, remote=${remoteTotalSize ?? "unknown"}). Keeping local file and aborting to avoid restart from zero.`
       );
     }