From a7c82de4a722d067d1b8c331d6ccc0ef2b98430a Mon Sep 17 00:00:00 2001
From: Moyasee <terranoiz@icloud.com>
Date: Tue, 6 Jan 2026 19:59:52 +0200
Subject: [PATCH] refactor: enhance download management by prioritizing
 interrupted downloads and improving error logging

---
 src/main/main.ts                              | 57 +++++++++++++++++--
 .../services/download/js-http-downloader.ts   | 26 +++++++++
 2 files changed, 77 insertions(+), 6 deletions(-)

diff --git a/src/main/main.ts b/src/main/main.ts
index 12f5ea26..35f205e5 100644
--- a/src/main/main.ts
+++ b/src/main/main.ts
@@ -18,6 +18,7 @@ import {
   DeckyPlugin,
   DownloadSourcesChecker,
   WSClient,
+  logger,
 } from "@main/services";
 import { migrateDownloadSources } from "./helpers/migrate-download-sources";
 
@@ -73,18 +74,47 @@ export const loadState = async () => {
       return orderBy(games, "timestamp", "desc");
     });
 
-  downloads.forEach((download) => {
+  let interruptedDownload = null;
+
+  for (const download of downloads) {
+    const downloadKey = levelKeys.game(download.shop, download.objectId);
+
+    // Reset extracting state
     if (download.extracting) {
-      downloadsSublevel.put(levelKeys.game(download.shop, download.objectId), {
+      await downloadsSublevel.put(downloadKey, {
         ...download,
         extracting: false,
       });
     }
-  });
 
-  const [nextItemOnQueue] = downloads.filter((game) => game.queued);
+    // Find interrupted active download (download that was running when app closed)
+    // Mark it as paused but remember it for auto-resume
+    if (download.status === "active" && !interruptedDownload) {
+      interruptedDownload = download;
+      await downloadsSublevel.put(downloadKey, {
+        ...download,
+        status: "paused",
+      });
+    } else if (download.status === "active") {
+      // Mark other active downloads as paused
+      await downloadsSublevel.put(downloadKey, {
+        ...download,
+        status: "paused",
+      });
+    }
+  }
 
-  const downloadsToSeed = downloads.filter(
+  // Re-fetch downloads after status updates
+  const updatedDownloads = await downloadsSublevel
+    .values()
+    .all()
+    .then((games) => orderBy(games, "timestamp", "desc"));
+
+  // Prioritize interrupted download, then queued downloads
+  const downloadToResume =
+    interruptedDownload ?? updatedDownloads.find((game) => game.queued);
+
+  const downloadsToSeed = updatedDownloads.filter(
     (game) =>
       game.shouldSeed &&
       game.downloader === Downloader.Torrent &&
@@ -92,7 +122,22 @@ export const loadState = async () => {
       game.uri !== null
   );
 
-  await DownloadManager.startRPC(nextItemOnQueue, downloadsToSeed);
+  // For torrents or if JS downloader is disabled, use Python RPC
+  const isTorrent = downloadToResume?.downloader === Downloader.Torrent;
+  const useJsDownloader =
+    userPreferences?.useNativeHttpDownloader && !isTorrent;
+
+  if (useJsDownloader && downloadToResume) {
+    // Start Python RPC for seeding only, then resume HTTP download with JS
+    await DownloadManager.startRPC(undefined, downloadsToSeed);
+    await DownloadManager.startDownload(downloadToResume).catch((err) => {
+      // If resume fails, just log it - user can manually retry
+      logger.error("Failed to auto-resume download:", err);
+    });
+  } else {
+    // Use Python RPC for everything (torrent or fallback)
+    await DownloadManager.startRPC(downloadToResume, downloadsToSeed);
+  }
 
   startMainLoop();
 
diff --git a/src/main/services/download/js-http-downloader.ts b/src/main/services/download/js-http-downloader.ts
index 563d8a6c..44a3af49 100644
--- a/src/main/services/download/js-http-downloader.ts
+++ b/src/main/services/download/js-http-downloader.ts
@@ -147,6 +147,32 @@ export class JsHttpDownloader {
       signal: this.abortController?.signal,
     });
 
+    // Handle 416 Range Not Satisfiable - existing file is larger than server file
+    // This happens when downloading same game from different source
+    if (response.status === 416 && startByte > 0) {
+      logger.log(
+        "[JsHttpDownloader] Range not satisfiable, deleting existing file and restarting"
+      );
+      if (fs.existsSync(filePath)) {
+        fs.unlinkSync(filePath);
+      }
+      this.bytesDownloaded = 0;
+      this.resetSpeedTracking();
+
+      // Retry without Range header
+      const headersWithoutRange = { ...requestHeaders };
+      delete headersWithoutRange["Range"];
+
+      return this.executeDownload(
+        url,
+        headersWithoutRange,
+        filePath,
+        0,
+        savePath,
+        usedFallback
+      );
+    }
+
     if (!response.ok && response.status !== 206) {
       throw new Error(`HTTP error! status: ${response.status}`);
     }