refactor: split main file into smaller modules for better maintainability

backend/managers/multiClientManager.js

@@ -0,0 +1,86 @@
+const fs = require('fs');
+const path = require('path');
+const { findClientPath } = require('../core/paths');
+const { downloadFile } = require('../utils/fileManager');
+const { getLatestClientVersion, getMultiClientVersion } = require('../services/versionManager');
+
+async function downloadMultiClient(gameDir, progressCallback) {
+  try {
+    if (process.platform !== 'win32') {
+      console.log('Multiplayer-client is only available for Windows');
+      return { success: false, reason: 'Platform not supported' };
+    }
+
+    const clientPath = findClientPath(gameDir);
+    if (!clientPath) {
+      throw new Error('Game client not found. Install game first.');
+    }
+
+    console.log('Downloading Multiplayer from server...');
+    if (progressCallback) {
+      progressCallback('Downloading Multiplayer...', null, null, null, null);
+    }
+
+    const clientUrl = 'http://3.10.208.30:3002/client';
+    const tempClientPath = path.join(path.dirname(clientPath), 'HytaleClient_temp.exe');
+
+    await downloadFile(clientUrl, tempClientPath, progressCallback);
+
+    const backupPath = path.join(path.dirname(clientPath), 'HytaleClient_original.exe');
+    if (!fs.existsSync(backupPath)) {
+      fs.copyFileSync(clientPath, backupPath);
+      console.log('Original client backed up');
+    }
+
+    fs.renameSync(tempClientPath, clientPath);
+    
+    if (progressCallback) {
+      progressCallback('Multiplayer installed', 100, null, null, null);
+    }
+    console.log('Multiplayer installed successfully');
+
+    return { success: true, installed: true };
+
+  } catch (error) {
+    console.error('Error installing Multiplayer:', error);
+    throw new Error(`Failed to install Multiplayer: ${error.message}`);
+  }
+}
+
+async function checkAndInstallMultiClient(gameDir, progressCallback) {
+  try {
+    if (process.platform !== 'win32') {
+      console.log('Multiplayer check skipped (Windows only)');
+      return { success: true, skipped: true, reason: 'Windows only' };
+    }
+
+    console.log('Checking for Multiplayer availability...');
+    
+    const [clientVersion, multiVersion] = await Promise.all([
+      getLatestClientVersion(),
+      getMultiClientVersion()
+    ]);
+
+    if (!multiVersion) {
+      console.log('Multiplayer not available');
+      return { success: true, skipped: true, reason: 'Multiplayer not available' };
+    }
+
+    if (clientVersion === multiVersion) {
+      console.log(`Versions match (${clientVersion}), installing Multiplayer...`);
+      return await downloadMultiClient(gameDir, progressCallback);
+    } else {
+      console.log(`Version mismatch: client=${clientVersion}, multi=${multiVersion}`);
+      return { success: true, skipped: true, reason: 'Version mismatch' };
+    }
+
+  } catch (error) {
+    console.error('Error checking Multiplayer:', error);
+    return { success: false, error: error.message };
+  }
+}
+
+module.exports = {
+  downloadMultiClient,
+  checkAndInstallMultiClient
+};