From 77b1acda57798a7aae9315c7bed1d810b637577a Mon Sep 17 00:00:00 2001
From: NotNite <hi@notnite.com>
Date: Mon, 20 Jan 2025 14:52:00 -0500
Subject: [PATCH] nativeFixes: Linux updater

---
 .../core-extensions/src/nativeFixes/host.ts   | 128 ++++++++++++++++++
 .../src/nativeFixes/manifest.json             |   9 +-
 2 files changed, 136 insertions(+), 1 deletion(-)

diff --git a/packages/core-extensions/src/nativeFixes/host.ts b/packages/core-extensions/src/nativeFixes/host.ts
index ddbcc054..749e0944 100644
--- a/packages/core-extensions/src/nativeFixes/host.ts
+++ b/packages/core-extensions/src/nativeFixes/host.ts
@@ -1,5 +1,10 @@
 import { app, nativeTheme } from "electron";
+import * as path from "node:path";
+import * as fs from "node:fs/promises";
+import * as fsSync from "node:fs";
+import { parseTarGzip } from "nanotar";
 
+const logger = moonlightHost.getLogger("nativeFixes/host");
 const enabledFeatures = app.commandLine.getSwitchValue("enable-features").split(",");
 
 moonlightHost.events.on("window-created", function (browserWindow) {
@@ -44,3 +49,126 @@ if ((moonlightHost.getConfigOption<boolean>("nativeFixes", "vaapi") ?? true) &&
 }
 
 app.commandLine.appendSwitch("enable-features", [...new Set(enabledFeatures)].join(","));
+
+if (process.platform === "linux" && moonlightHost.getConfigOption<boolean>("nativeFixes", "linuxUpdater")) {
+  const exePath = app.getPath("exe");
+  const appName = path.basename(exePath);
+  const targetDir = path.dirname(exePath);
+  const { releaseChannel }: { releaseChannel: string } = JSON.parse(
+    fsSync.readFileSync(path.join(targetDir, "resources", "build_info.json"), "utf8")
+  );
+
+  const updaterModule = require(path.join(moonlightHost.asarPath, "app_bootstrap", "hostUpdater.js"));
+  const updater = updaterModule.constructor;
+
+  async function doUpdate(cb: (percent: number) => void) {
+    logger.debug("Extracting to", targetDir);
+
+    const exists = (path: string) =>
+      fs
+        .stat(path)
+        .then(() => true)
+        .catch(() => false);
+
+    const url = `https://discord.com/api/download/${releaseChannel}?platform=linux&format=tar.gz`;
+    const resp = await fetch(url, {
+      cache: "no-store"
+    });
+
+    const reader = resp.body!.getReader();
+    const contentLength = parseInt(resp.headers.get("Content-Length") ?? "0");
+    logger.info(`Expecting ${contentLength} bytes for the update`);
+    const bytes = new Uint8Array(contentLength);
+    let pos = 0;
+    let lastPercent = 0;
+
+    while (true) {
+      const { done, value } = await reader.read();
+      if (done) {
+        break;
+      } else {
+        bytes.set(value, pos);
+        pos += value.length;
+
+        const newPercent = Math.floor((pos / contentLength) * 100);
+        if (lastPercent !== newPercent) {
+          lastPercent = newPercent;
+          cb(newPercent);
+        }
+      }
+    }
+
+    const files = await parseTarGzip(bytes);
+
+    for (const file of files) {
+      if (!file.data) continue;
+      // @ts-expect-error What do you mean their own types are wrong
+      if (file.type !== "file") continue;
+
+      // Discord update files are inside of a main "Discord(PTB|Canary)" folder
+      const filePath = file.name.replace(`${appName}/`, "");
+      logger.info("Extracting", filePath);
+
+      let targetFilePath = path.join(targetDir, filePath);
+      if (filePath === "resources/app.asar") {
+        // You tried
+        targetFilePath = path.join(targetDir, "resources", "_app.asar");
+      } else if (filePath === appName) {
+        // Can't write over the executable? Just move it! 4head
+        if (await exists(targetFilePath)) {
+          await fs.rename(targetFilePath, targetFilePath + ".bak");
+          await fs.unlink(targetFilePath + ".bak");
+        }
+      }
+      const targetFileDir = path.dirname(targetFilePath);
+
+      if (!(await exists(targetFileDir))) await fs.mkdir(targetFileDir, { recursive: true });
+      await fs.writeFile(targetFilePath, file.data);
+
+      const mode = file.attrs?.mode;
+      if (mode != null) {
+        // Not sure why this slice is needed
+        await fs.chmod(targetFilePath, mode.slice(-3));
+      }
+    }
+
+    logger.debug("Done updating");
+  }
+
+  const realEmit = updater.prototype.emit;
+  updater.prototype.emit = function (event: string, ...args: any[]) {
+    // Arrow functions don't bind `this` :D
+    const call = (event: string, ...args: any[]) => realEmit.call(this, event, ...args);
+
+    if (event === "update-manually") {
+      const latestVerStr: string = args[0];
+      logger.debug("update-manually called, intercepting", latestVerStr);
+      call("update-available");
+
+      (async () => {
+        try {
+          await doUpdate((progress) => {
+            call("update-progress", progress);
+          });
+          // Copied from the win32 updater
+          this.updateVersion = latestVerStr;
+          call(
+            "update-downloaded",
+            {},
+            releaseChannel,
+            latestVerStr,
+            new Date(),
+            this.updateUrl,
+            this.quitAndInstall.bind(this)
+          );
+        } catch (e) {
+          logger.error("Error updating", e);
+        }
+      })();
+
+      return this;
+    } else {
+      return realEmit.call(this, event, ...args);
+    }
+  };
+}
diff --git a/packages/core-extensions/src/nativeFixes/manifest.json b/packages/core-extensions/src/nativeFixes/manifest.json
index f3f1321b..a17ca7e9 100644
--- a/packages/core-extensions/src/nativeFixes/manifest.json
+++ b/packages/core-extensions/src/nativeFixes/manifest.json
@@ -4,7 +4,7 @@
   "meta": {
     "name": "Native Fixes",
     "tagline": "Various configurable fixes for Discord and Electron",
-    "authors": ["Cynosphere", "adryd"],
+    "authors": ["Cynosphere", "adryd", "NotNite"],
     "tags": ["fixes"]
   },
   "environment": "desktop",
@@ -43,6 +43,13 @@
       "description": "Provides hardware accelerated video encode and decode. Has no effect on other operating systems",
       "type": "boolean",
       "default": true
+    },
+    "linuxUpdater": {
+      "advice": "restart",
+      "displayName": "Linux Updater",
+      "description": "Actually implements updating Discord on Linux. Has no effect on other operating systems",
+      "type": "boolean",
+      "default": false
     }
   },
   "apiLevel": 2