initial commit

.gitignore

@@ -0,0 +1,31 @@
+# Node.js
+node_modules/
+npm-debug.log
+yarn-error.log
+
+# Environment Variables (CRITICAL)
+.env
+.env.*
+!.env.example
+
+# Build Outputs
+dist/
+build/
+bin/
+server/
+
+# Generated WireGuard configs
+*.conf
+
+# OS/Editor Files
+.DS_Store
+.idea/
+.vscode/
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?
+
+# ProtonVPN local DBs or cache if generated locally
+*.db

backend/backend.Dockerfile

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+# Multi-stage build for Go + Node.js Backend
+# Stage 1: Build Go binary
+FROM golang:1.24-alpine AS builder
+# Use latest stable go that works (docker tag might not have 1.25.6 yet, alpine is fine)
+# Since the go.mod says 1.25.6, we'll let it use the toolchain if 1.24 is the base, or we just rely on standard go compilation.
+RUN apk add --no-cache git make gcc musl-dev
+
+WORKDIR /src
+COPY protonvpn-wg-confgen/ ./
+ENV GOTOOLCHAIN=auto
+RUN go build -o /bin/protonvpn-wg-confgen cmd/protonvpn-wg/main.go
+
+# Stage 2: Node.js Backend Production setup
+FROM node:22-alpine
+WORKDIR /app
+
+# Install CA certs needed for Proton API calls
+RUN apk add --no-cache ca-certificates tzdata
+
+# Copy the compiled Go binary from Stage 1
+COPY --from=builder /bin/protonvpn-wg-confgen /usr/local/bin/protonvpn-wg-confgen
+
+# Setup the Node JS backend
+COPY backend/package.json ./
+RUN npm install
+COPY backend/ ./
+CMD ["npm", "run", "dev"]

backend/package.json

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+{
+  "name": "protonvpn-webui-backend",
+  "version": "1.0.0",
+  "type": "module",
+  "scripts": {
+    "start": "node server.js",
+    "dev": "node --watch server.js"
+  },
+  "dependencies": {
+    "express": "^4.19.2",
+    "cors": "^2.8.5",
+    "helmet": "^7.1.0"
+  }
+}

backend/server.js

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+import express from 'express';
+import cors from 'cors';
+import { spawn } from 'child_process';
+import crypto from 'crypto';
+import path from 'path';
+import fs from 'fs/promises';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+const app = express();
+const port = process.env.PORT || 3000;
+
+app.use(cors());
+app.use(express.json());
+
+// In-memory process store for SSE and interactive stdin
+const activeTasks = new Map();
+
+// Helper to construct command arguments
+function buildArgs(body, outputFile) {
+  const args = [];
+  
+  const username = body.username || process.env.PROTON_USERNAME;
+  const password = body.password || process.env.PROTON_PASSWORD;
+  
+  if (username) {
+    args.push('-username', username);
+  }
+  if (password) {
+    args.push('-password', password);
+  }
+  if (body.countries) {
+    args.push('-countries', body.countries); // e.g., "US,NL"
+  }
+  
+  args.push('-output', outputFile);
+  
+  if (body.p2pOnly) args.push('-p2p-only');
+  if (body.secureCore) args.push('-secure-core');
+  if (body.freeOnly) args.push('-free-only');
+  if (body.ipv6) args.push('-ipv6');
+  if (body.accelerator === false) args.push('-accelerator=false');
+  if (body.duration) args.push('-duration', body.duration);
+  
+  // We use clear-session to force fresh auth if needed, or default behavior
+  // For web UI, maybe we want to always force clear session so it doesn't use old cached sessions 
+  // that belong to root from inside docker? Let's give user option, typical web user wants it fresh.
+  args.push('-clear-session');
+
+  return args;
+}
+
+app.post('/api/generate', async (req, res) => {
+  const taskId = crypto.randomUUID();
+  const outputFile = path.join(__dirname, `protonvpn-${taskId}.conf`);
+  
+  const args = buildArgs(req.body, outputFile);
+  
+  // Default to system PATH if compiled, handle local testing fallback
+  let binPath = 'protonvpn-wg-confgen';
+  
+  console.log(`Starting task ${taskId}: ${binPath} ${args.join(' ')}`);
+  
+  // Create process
+  const child = spawn(binPath, args);
+  
+  // Store task
+  activeTasks.set(taskId, {
+    child,
+    outputFile,
+    clients: []
+  });
+
+  child.stdout.on('data', (data) => {
+    const text = data.toString();
+    console.log(`[${taskId} stdout]`, text);
+    broadcastToClients(taskId, 'log', { text });
+    
+    // Check for interactive prompts from Go tool
+    if (text.includes('2FA Code:')) {
+      broadcastToClients(taskId, 'require_2fa', {});
+    }
+  });
+
+  child.stderr.on('data', (data) => {
+    const text = data.toString();
+    console.log(`[${taskId} stderr]`, text);
+    broadcastToClients(taskId, 'log', { text, error: true });
+  });
+
+  child.on('close', async (code) => {
+    console.log(`[${taskId} exited with code ${code}]`);
+    let fileContent = null;
+    let success = code === 0;
+    
+    if (success) {
+      try {
+        fileContent = await fs.readFile(outputFile, 'utf8');
+        // Clean up the file
+        await fs.unlink(outputFile).catch(() => {});
+      } catch (err) {
+        console.error('Failed to read configuration file', err);
+        success = false;
+      }
+    }
+    
+    broadcastToClients(taskId, 'complete', { success, code, fileContent });
+    
+    // Cleanup task memory shortly after complete
+    setTimeout(() => {
+      const task = activeTasks.get(taskId);
+      if (task) {
+        task.clients.forEach(c => c.end());
+        activeTasks.delete(taskId);
+      }
+    }, 5000);
+  });
+
+  child.on('error', (err) => {
+    console.error(`[${taskId} ERROR]`, err);
+    broadcastToClients(taskId, 'log', { text: `Failed to start process: ${err.message}`, error: true });
+    broadcastToClients(taskId, 'complete', { success: false, code: -1 });
+  });
+
+  res.json({ taskId });
+});
+
+// SSE endpoint
+app.get('/api/stream/:taskId', (req, res) => {
+  const { taskId } = req.params;
+  const task = activeTasks.get(taskId);
+  
+  if (!task) {
+    return res.status(404).send('Task not found');
+  }
+
+  res.setHeader('Content-Type', 'text/event-stream');
+  res.setHeader('Cache-Control', 'no-cache');
+  res.setHeader('Connection', 'keep-alive');
+  res.flushHeaders();
+
+  task.clients.push(res);
+  
+  req.on('close', () => {
+    task.clients = task.clients.filter(client => client !== res);
+  });
+});
+
+app.post('/api/2fa', (req, res) => {
+  const { taskId, code } = req.body;
+  const task = activeTasks.get(taskId);
+  
+  if (!task) {
+    return res.status(404).json({ error: 'Task not found' });
+  }
+  
+  if (!task.child.stdin.writable) {
+    return res.status(400).json({ error: 'Process not accepting input' });
+  }
+
+  // Write the code followed by newline to the process stdin
+  task.child.stdin.write(`${code}\n`);
+  res.json({ success: true });
+});
+
+const POPULAR_COUNTRIES = [
+  { code: 'US', name: 'United States' },
+  { code: 'NL', name: 'Netherlands' },
+  { code: 'CH', name: 'Switzerland' },
+  { code: 'JP', name: 'Japan' },
+  { code: 'UK', name: 'United Kingdom' },
+  { code: 'DE', name: 'Germany' },
+  { code: 'CA', name: 'Canada' },
+  { code: 'FR', name: 'France' },
+  { code: 'SE', name: 'Sweden' },
+  { code: 'IS', name: 'Iceland' }
+];
+
+app.get('/api/countries', (req, res) => {
+  res.json(POPULAR_COUNTRIES);
+});
+
+// Helper for SSE
+function broadcastToClients(taskId, eventName, data) {
+  const task = activeTasks.get(taskId);
+  if (!task) return;
+  
+  const payload = `event: ${eventName}\ndata: ${JSON.stringify(data)}\n\n`;
+  task.clients.forEach(client => client.write(payload));
+}
+
+app.listen(port, () => {
+  console.log(`Backend server running on http://localhost:${port}`);
+});

docker-compose.yml

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+services:
+  backend:
+    build:
+      context: .
+      dockerfile: backend/backend.Dockerfile
+    ports:
+      - "3000:3000"
+    volumes:
+      - ./backend:/app
+      - /app/node_modules
+    environment:
+      - PORT=3000
+    env_file:
+      - .env
+
+  frontend:
+    build:
+      context: ./frontend
+      dockerfile: dev.Dockerfile
+    ports:
+      - "5173:5173"
+    volumes:
+      - ./frontend:/app
+      - /app/node_modules
+    depends_on:
+      - backend

frontend/dev.Dockerfile

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+FROM node:22-alpine
+WORKDIR /app
+COPY package.json ./
+RUN npm install
+CMD ["npm", "run", "dev", "--", "--host"]

frontend/index.html

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+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <link rel="icon" type="image/svg+xml" href="/vite.svg" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>ProtonVPN Config Generator</title>
+  </head>
+  <body class="bg-zinc-950 text-white min-h-screen font-sans antialiased selection:bg-purple-500/30">
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>

frontend/package.json

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+{
+  "name": "protonvpn-webui-frontend",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "lint": "eslint . --ext ts,tsx --report-unused-disable-directives --max-warnings 0",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "react": "^18.3.1",
+    "react-dom": "^18.3.1",
+    "tailwindcss": "^3.4.4",
+    "postcss": "^8.4.38",
+    "autoprefixer": "^10.4.19"
+  },
+  "devDependencies": {
+    "@types/react": "^18.3.3",
+    "@types/react-dom": "^18.3.0",
+    "@vitejs/plugin-react": "^4.3.1",
+    "typescript": "^5.2.2",
+    "vite": "^5.3.4"
+  }
+}

frontend/postcss.config.js

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+export default {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+}

frontend/src/App.tsx

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+import React, { useState, useEffect, useRef } from 'react';
+
+const COUNTRIES = [
+  { code: 'AR', name: 'Argentina' },
+  { code: 'AU', name: 'Australia' },
+  { code: 'AT', name: 'Austria' },
+  { code: 'BE', name: 'Belgium' },
+  { code: 'BR', name: 'Brazil' },
+  { code: 'BG', name: 'Bulgaria' },
+  { code: 'CA', name: 'Canada' },
+  { code: 'CL', name: 'Chile' },
+  { code: 'CO', name: 'Colombia' },
+  { code: 'CR', name: 'Costa Rica' },
+  { code: 'HR', name: 'Croatia' },
+  { code: 'CY', name: 'Cyprus' },
+  { code: 'CZ', name: 'Czechia' },
+  { code: 'DK', name: 'Denmark' },
+  { code: 'EE', name: 'Estonia' },
+  { code: 'FI', name: 'Finland' },
+  { code: 'FR', name: 'France' },
+  { code: 'GE', name: 'Georgia' },
+  { code: 'DE', name: 'Germany' },
+  { code: 'GR', name: 'Greece' },
+  { code: 'HK', name: 'Hong Kong' },
+  { code: 'HU', name: 'Hungary' },
+  { code: 'IS', name: 'Iceland' },
+  { code: 'IN', name: 'India' },
+  { code: 'IE', name: 'Ireland' },
+  { code: 'IL', name: 'Israel' },
+  { code: 'IT', name: 'Italy' },
+  { code: 'JP', name: 'Japan' },
+  { code: 'LV', name: 'Latvia' },
+  { code: 'LT', name: 'Lithuania' },
+  { code: 'LU', name: 'Luxembourg' },
+  { code: 'MY', name: 'Malaysia' },
+  { code: 'MX', name: 'Mexico' },
+  { code: 'MD', name: 'Moldova' },
+  { code: 'NL', name: 'Netherlands' },
+  { code: 'NZ', name: 'New Zealand' },
+  { code: 'NO', name: 'Norway' },
+  { code: 'PE', name: 'Peru' },
+  { code: 'PH', name: 'Philippines' },
+  { code: 'PL', name: 'Poland' },
+  { code: 'PT', name: 'Portugal' },
+  { code: 'RO', name: 'Romania' },
+  { code: 'RS', name: 'Serbia' },
+  { code: 'SG', name: 'Singapore' },
+  { code: 'SK', name: 'Slovakia' },
+  { code: 'SI', name: 'Slovenia' },
+  { code: 'ZA', name: 'South Africa' },
+  { code: 'KR', name: 'South Korea' },
+  { code: 'ES', name: 'Spain' },
+  { code: 'SE', name: 'Sweden' },
+  { code: 'CH', name: 'Switzerland' },
+  { code: 'TW', name: 'Taiwan' },
+  { code: 'TR', name: 'Turkey' },
+  { code: 'UA', name: 'Ukraine' },
+  { code: 'AE', name: 'United Arab Emirates' },
+  { code: 'UK', name: 'United Kingdom' },
+  { code: 'US', name: 'United States' },
+  { code: 'VN', name: 'Vietnam' }
+];
+
+const getFlagImg = (countryCode: string) => {
+  return (
+    <img 
+      src={`https://flagcdn.com/w40/${countryCode.toLowerCase()}.png`}
+      width="24"
+      alt={countryCode}
+      className="inline-block rounded-[2px] shadow-[0_0_2px_rgba(0,0,0,0.5)]"
+    />
+  );
+};
+
+export default function App() {
+  const [selectedCountries, setSelectedCountries] = useState<string[]>([]);
+  const [isCountryOpen, setIsCountryOpen] = useState(false);
+  const [options, setOptions] = useState({
+    p2pOnly: true,
+    secureCore: false,
+    freeOnly: false,
+    ipv6: false,
+    accelerator: true,
+    duration: '365d'
+  });
+
+  const [taskId, setTaskId] = useState<string | null>(null);
+  const [isGenerating, setIsGenerating] = useState(false);
+  const [logs, setLogs] = useState<{text: string, error?: boolean}[]>([]);
+  const [require2FA, setRequire2FA] = useState(false);
+  const [twoFACode, setTwoFACode] = useState('');
+  const [downloadData, setDownloadData] = useState<string | null>(null);
+  
+  const logsEndRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    logsEndRef.current?.scrollIntoView({ behavior: 'smooth' });
+  }, [logs]);
+
+  const toggleCountry = (code: string) => {
+    setSelectedCountries(prev => 
+      prev.includes(code) ? prev.filter(c => c !== code) : [...prev, code]
+    );
+  };
+
+  const handleGenerate = async (e: React.FormEvent) => {
+    e.preventDefault();
+    if (selectedCountries.length === 0) {
+      alert("Please select at least one country");
+      return;
+    }
+    
+    setIsGenerating(true);
+    setLogs([]);
+    setRequire2FA(false);
+    setDownloadData(null);
+    setTaskId(null);
+
+    try {
+      const res = await fetch('/api/generate', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          countries: selectedCountries.join(','),
+          ...options
+        })
+      });
+      
+      const { taskId } = await res.json();
+      setTaskId(taskId);
+      
+      const es = new EventSource(`/api/stream/${taskId}`);
+      
+      es.addEventListener('log', (e) => {
+        const data = JSON.parse(e.data);
+        setLogs(prev => [...prev, data]);
+      });
+      
+      es.addEventListener('require_2fa', () => {
+        setRequire2FA(true);
+      });
+      
+      es.addEventListener('complete', (e) => {
+        const data = JSON.parse(e.data);
+        setLogs(prev => [...prev, { text: `Process completed with code ${data.code}` }]);
+        setIsGenerating(false);
+        if (data.success && data.fileContent) {
+          setDownloadData(data.fileContent);
+        }
+        es.close();
+      });
+      
+      es.onerror = () => {
+        setLogs(prev => [...prev, { text: 'Lost connection to stream', error: true }]);
+        setIsGenerating(false);
+        es.close();
+      };
+      
+    } catch (err) {
+      setLogs([{ text: `Failed to initiate generation: ${err}`, error: true }]);
+      setIsGenerating(false);
+    }
+  };
+
+  const submit2FA = async (e: React.FormEvent) => {
+    e.preventDefault();
+    if (!taskId || !twoFACode) return;
+    
+    setRequire2FA(false);
+    setLogs(prev => [...prev, { text: `> Submitting 2FA Code: ***`, error: false }]);
+    
+    await fetch('/api/2fa', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ taskId, code: twoFACode })
+    });
+    
+    setTwoFACode('');
+  };
+
+  const downloadFile = () => {
+    if (!downloadData) return;
+    const blob = new Blob([downloadData], { type: 'text/plain' });
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement('a');
+    a.href = url;
+    a.download = `protonvpn-${selectedCountries.join('_')}.conf`;
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+    URL.revokeObjectURL(url);
+  };
+
+  return (
+    <div className="min-h-screen bg-[#121015] flex flex-col items-center p-6 relative">
+      {/* Background aesthetic */}
+      <div className="absolute top-[-20%] left-[-10%] w-[50%] h-[50%] bg-[#6d4aff]/10 blur-[120px] rounded-full pointer-events-none" />
+      <div className="absolute top-[30%] right-[-10%] w-[40%] h-[60%] bg-[#2bbd7e]/5 blur-[120px] rounded-full pointer-events-none" />
+
+      <div className="max-w-6xl w-full flex flex-col gap-8 z-10">
+        <header className="flex flex-col md:flex-row items-center justify-between gap-4">
+          <div>
+            <h1 className="text-3xl font-extrabold text-transparent bg-clip-text bg-gradient-to-r from-[#6d4aff] to-[#937bff] uppercase tracking-wider">
+              Proton WireGuard
+            </h1>
+            <p className="text-zinc-400 mt-1 font-medium">Headless Configuration Generator</p>
+          </div>
+          <p className="text-xs text-zinc-500 bg-white/5 py-2 px-4 rounded-full border border-white/10 backdrop-blur-sm">
+            Powered by open-source protonvpn-wg-confgen
+          </p>
+        </header>
+        
+        <div className="grid grid-cols-1 lg:grid-cols-2 gap-8">
+          
+          {/* Controls Panel */}
+          <div className="bg-[#1c1924]/80 p-8 rounded-3xl border border-white/5 shadow-2xl backdrop-blur-md flex flex-col gap-6">
+            <h2 className="text-xl font-bold border-b border-white/5 pb-4">Connection Settings</h2>
+            
+            <form id="gen-form" onSubmit={handleGenerate} className="flex flex-col gap-6">
+
+
+              <div>
+                <label className="block text-xs font-semibold text-zinc-400 mb-3 uppercase tracking-wide">Target Countries</label>
+                <div className="flex flex-col gap-2">
+                  <button
+                    type="button"
+                    onClick={() => setIsCountryOpen(!isCountryOpen)}
+                    className="w-full bg-black/40 border border-white/10 rounded-xl px-4 py-3 text-left focus:outline-none focus:border-[#6d4aff] transition-colors flex justify-between items-center text-zinc-300 shadow-sm"
+                  >
+                    <span className="flex items-center gap-2 flex-wrap">
+                      {selectedCountries.length === 0 
+                        ? 'Toggle countries list...' 
+                        : selectedCountries.map(c => (
+                            <span key={c} className="flex items-center gap-1.5 bg-white/10 px-2 py-0.5 rounded-md text-xs font-bold text-white shadow-sm">
+                              {getFlagImg(c)} {c}
+                            </span>
+                          ))}
+                    </span>
+                    <svg className={`w-5 h-5 shrink-0 transition-transform ${isCountryOpen ? 'rotate-180' : ''}`} fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 9l-7 7-7-7" />
+                    </svg>
+                  </button>
+                  
+                  {isCountryOpen && (
+                    <div className="w-full bg-black/20 border border-white/5 rounded-xl max-h-72 overflow-y-auto overflow-x-hidden p-2 backdrop-blur-sm">
+                      <div className="grid grid-cols-1 sm:grid-cols-2 gap-2">
+                        {COUNTRIES.map(country => (
+                          <label
+                            key={country.code}
+                            className={`flex items-center gap-3 px-3 py-2 rounded-lg cursor-pointer transition-colors border max-w-full ${
+                              selectedCountries.includes(country.code) 
+                                ? 'bg-[#6d4aff]/20 border-[#6d4aff]/50 text-white' 
+                                : 'border-transparent hover:bg-white/5 text-zinc-300'
+                            }`}
+                          >
+                            <input
+                              type="checkbox"
+                              className="hidden"
+                              checked={selectedCountries.includes(country.code)}
+                              onChange={() => toggleCountry(country.code)}
+                            />
+                            <div className={`w-4 h-4 rounded border flex items-center justify-center shrink-0 transition-colors ${
+                              selectedCountries.includes(country.code) ? 'bg-[#6d4aff] border-[#6d4aff]' : 'border-white/20 bg-black/40'
+                            }`}>
+                              {selectedCountries.includes(country.code) && (
+                                <svg className="w-3 h-3 text-white" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+                                  <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={3} d="M5 13l4 4L19 7" />
+                                </svg>
+                              )}
+                            </div>
+                            <span className="shrink-0 flex items-center justify-center w-[24px]">
+                              {getFlagImg(country.code)}
+                            </span>
+                            <span className="text-sm font-medium truncate shrink min-w-0" title={country.name}>{country.name}</span>
+                          </label>
+                        ))}
+                      </div>
+                    </div>
+                  )}
+                </div>
+              </div>
+
+              <div>
+                <label className="block text-xs font-semibold text-zinc-400 mb-3 uppercase tracking-wide">Advanced Options</label>
+                <div className="grid grid-cols-2 gap-3">
+                  {[
+                    { key: 'p2pOnly', label: 'P2P Optimized' },
+                    { key: 'secureCore', label: 'Secure Core' },
+                    { key: 'freeOnly', label: 'Free Tier Only' },
+                    { key: 'ipv6', label: 'Enable IPv6' },
+                    { key: 'accelerator', label: 'VPN Accelerator' }
+                  ].map(opt => (
+                    <label key={opt.key} className="flex items-center gap-3 cursor-pointer group">
+                      <div className={`w-5 h-5 rounded border flex items-center justify-center transition-colors ${
+                        options[opt.key as keyof typeof options] ? 'bg-[#6d4aff] border-[#6d4aff]' : 'border-white/20 bg-black/40 group-hover:border-white/40'
+                      }`}>
+                        {options[opt.key as keyof typeof options] && (
+                          <svg className="w-3 h-3 text-white" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+                            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={3} d="M5 13l4 4L19 7" />
+                          </svg>
+                        )}
+                      </div>
+                      <span className="text-sm text-zinc-300">{opt.label}</span>
+                      <input 
+                        type="checkbox" 
+                        className="hidden"
+                        checked={options[opt.key as keyof typeof options] as boolean}
+                        onChange={e => setOptions({...options, [opt.key]: e.target.checked})}
+                      />
+                    </label>
+                  ))}
+                </div>
+              </div>
+
+              <div className="pt-4 border-t border-white/5">
+                <button
+                  type="submit"
+                  disabled={isGenerating}
+                  className="w-full bg-gradient-to-r from-[#6d4aff] to-[#937bff] hover:opacity-90 text-white font-bold py-4 rounded-xl shadow-lg transition-transform active:scale-[0.98] disabled:opacity-50 disabled:cursor-not-allowed"
+                >
+                  {isGenerating ? 'Generating...' : 'Generate Configuration'}
+                </button>
+              </div>
+            </form>
+          </div>
+
+          {/* Terminal / Output Panel */}
+          <div className="bg-black/80 p-6 rounded-3xl border border-white/10 shadow-2xl backdrop-blur-xl flex flex-col h-[600px]">
+            <div className="flex items-center gap-2 mb-4 px-2">
+              <div className="w-3 h-3 rounded-full bg-red-500/80"></div>
+              <div className="w-3 h-3 rounded-full bg-yellow-500/80"></div>
+              <div className="w-3 h-3 rounded-full bg-green-500/80"></div>
+              <span className="ml-2 text-xs font-mono text-zinc-500">generator.log</span>
+            </div>
+            
+            <div className="flex-1 overflow-y-auto terminal-scroll font-mono text-xs md:text-sm bg-[#050505] rounded-xl p-4 border border-white/5">
+              {logs.length === 0 && !isGenerating && (
+                 <p className="text-zinc-600 italic">Waiting for execution...</p>
+              )}
+              {logs.map((log, i) => (
+                <div key={i} className={`mb-1 ${log.error ? 'text-red-400' : 'text-zinc-300'}`}>
+                  {log.text.split('\n').map((line, j) => (
+                    <div key={j} className="break-all whitespace-pre-wrap">{line}</div>
+                  ))}
+                </div>
+              ))}
+              <div ref={logsEndRef} />
+            </div>
+
+            {/* Success Download */}
+            {downloadData && (
+              <div className="mt-4 animate-in fade-in slide-in-from-bottom-4">
+                <button
+                  onClick={downloadFile}
+                  className="w-full bg-[#2bbd7e] border border-[#2bbd7e] text-[#2bbd7e] bg-opacity-20 font-bold py-3 rounded-xl hover:bg-opacity-30 transition-colors flex items-center justify-center gap-2"
+                >
+                  <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path strokeLinecap="round" strokeLinejoin="round" strokeWidth="2" d="M4 16v1a3 3 0 003 3h10a3 3 0 003-3v-1m-4-4l-4 4m0 0l-4-4m4 4V4" />
+                  </svg>
+                  Download WireGuard Config
+                </button>
+              </div>
+            )}
+          </div>
+
+        </div>
+      </div>
+
+      {/* 2FA Modal */}
+      {require2FA && (
+        <div className="fixed inset-0 bg-black/80 backdrop-blur-md z-50 flex items-center justify-center p-4 animate-in fade-in">
+          <div className="bg-[#1c1924] border border-[#6d4aff]/30 p-8 rounded-3xl max-w-sm w-full shadow-2xl">
+            <h3 className="text-2xl font-bold mb-2 flex items-center gap-2">
+              <svg className="w-6 h-6 text-[#6d4aff]" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth="2" d="M12 15v2m-6 4h12a2 2 0 002-2v-6a2 2 0 00-2-2H6a2 2 0 00-2 2v6a2 2 0 002 2zm10-10V7a4 4 0 00-8 0v4h8z" />
+              </svg>
+              Two-Factor Auth
+            </h3>
+            <p className="text-zinc-400 text-sm mb-6">Your Proton account requires a TOTP code to authenticate the VPN API.</p>
+            
+            <form onSubmit={submit2FA}>
+              <input
+                type="text"
+                autoFocus
+                maxLength={6}
+                value={twoFACode}
+                onChange={e => setTwoFACode(e.target.value.replace(/\D/g, ''))}
+                placeholder="000 000"
+                className="w-full bg-black/60 border border-white/10 rounded-xl px-4 py-4 text-center text-2xl tracking-widest font-mono focus:outline-none focus:border-[#6d4aff] transition-colors mb-6"
+              />
+              <button
+                type="submit"
+                disabled={twoFACode.length !== 6}
+                className="w-full bg-white text-black font-bold py-3 rounded-xl disabled:opacity-50 transition-opacity"
+              >
+                Verify & Continue
+              </button>
+            </form>
+          </div>
+        </div>
+      )}
+    </div>
+  );
+}

frontend/src/index.css

@@ -0,0 +1,31 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+:root {
+  --color-proton-purple: #6d4aff;
+  --color-proton-dark: #121015;
+  --color-proton-card: #1c1924;
+  --color-proton-accent: #937bff;
+  --color-proton-green: #2bbd7e;
+  --font-sans: "Inter", system-ui, sans-serif;
+}
+
+body {
+  background-color: var(--color-proton-dark);
+}
+
+/* Custom scrollbar for terminal */
+.terminal-scroll::-webkit-scrollbar {
+  width: 8px;
+}
+.terminal-scroll::-webkit-scrollbar-track {
+  background: rgba(0,0,0,0.2);
+}
+.terminal-scroll::-webkit-scrollbar-thumb {
+  background: rgba(109, 74, 255, 0.4);
+  border-radius: 4px;
+}
+.terminal-scroll::-webkit-scrollbar-thumb:hover {
+  background: rgba(109, 74, 255, 0.6);
+}

frontend/src/main.tsx

@@ -0,0 +1,10 @@
+import React from 'react'
+import ReactDOM from 'react-dom/client'
+import App from './App.tsx'
+import './index.css'
+
+ReactDOM.createRoot(document.getElementById('root')!).render(
+  <React.StrictMode>
+    <App />
+  </React.StrictMode>,
+)

frontend/tailwind.config.js

@@ -0,0 +1,11 @@
+/** @type {import('tailwindcss').Config} */
+export default {
+  content: [
+    "./index.html",
+    "./src/**/*.{js,ts,jsx,tsx}",
+  ],
+  theme: {
+    extend: {},
+  },
+  plugins: [],
+}

frontend/tsconfig.json

@@ -0,0 +1,21 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "useDefineForClassFields": true,
+    "lib": ["ES2020", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "skipLibCheck": true,
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "noEmit": true,
+    "jsx": "react-jsx",
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noFallthroughCasesInSwitch": true
+  },
+  "include": ["src"],
+  "references": [{ "path": "./tsconfig.node.json" }]
+}

frontend/tsconfig.node.json

@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "composite": true,
+    "skipLibCheck": true,
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "allowSyntheticDefaultImports": true,
+    "strict": true
+  },
+  "include": ["vite.config.ts"]
+}

frontend/vite.config.ts

@@ -0,0 +1,18 @@
+import { defineConfig } from 'vite'
+import react from '@vitejs/plugin-react'
+
+export default defineConfig({
+  plugins: [
+    react(),
+  ],
+  server: {
+    host: '0.0.0.0', // needed for docker
+    port: 5173,
+    proxy: {
+      '/api': {
+        target: 'http://backend:3000',
+        changeOrigin: true
+      }
+    }
+  }
+})

protonvpn-wg-confgen/.github/workflows/ci.yml

@@ -0,0 +1,124 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+env:
+  GO_VERSION: "1.25.6"
+  GOLANGCI_LINT_VERSION: "v2.8.0"
+
+jobs:
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Set up Go
+        uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5 # v6.2.0
+        with:
+          go-version: ${{ env.GO_VERSION }}
+          cache: true
+
+      - name: Run go fmt
+        run: |
+          if [ -n "$(gofmt -s -l . | grep -v '^vendor/')" ]; then
+            echo "Go code is not formatted:"
+            gofmt -s -d . | grep -v '^vendor/'
+            exit 1
+          fi
+
+      - name: Run go vet
+        run: go vet ./...
+
+      - name: Run golangci-lint
+        uses: golangci/golangci-lint-action@1e7e51e771db61008b38414a730f564565cf7c20 # v9.2.0
+        with:
+          version: ${{ env.GOLANGCI_LINT_VERSION }}
+
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Set up Go
+        uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5 # v6.2.0
+        with:
+          go-version: ${{ env.GO_VERSION }}
+          cache: true
+
+      - name: Run tests
+        run: go test -v -race ./...
+
+  build:
+    name: Build (${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Set up Go
+        uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5 # v6.2.0
+        with:
+          go-version: ${{ env.GO_VERSION }}
+          cache: true
+
+      - name: Build (native)
+        run: go build -o build/protonvpn-wg-confgen${{ matrix.os == 'windows-latest' && '.exe' || '' }} cmd/protonvpn-wg/main.go
+
+  cross-compile:
+    name: Cross-compile
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Linux
+          - goos: linux
+            goarch: amd64
+          - goos: linux
+            goarch: arm64
+          - goos: linux
+            goarch: arm
+          # macOS
+          - goos: darwin
+            goarch: amd64
+          - goos: darwin
+            goarch: arm64
+          # Windows
+          - goos: windows
+            goarch: amd64
+            ext: .exe
+          - goos: windows
+            goarch: arm64
+            ext: .exe
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Set up Go
+        uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5 # v6.2.0
+        with:
+          go-version: ${{ env.GO_VERSION }}
+          cache: true
+
+      - name: Build ${{ matrix.goos }}/${{ matrix.goarch }}
+        env:
+          GOOS: ${{ matrix.goos }}
+          GOARCH: ${{ matrix.goarch }}
+          CGO_ENABLED: "0"
+        run: |
+          mkdir -p build
+          go build -o build/protonvpn-wg-confgen-${{ matrix.goos }}-${{ matrix.goarch }}${{ matrix.ext }} cmd/protonvpn-wg/main.go
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
+        with:
+          name: protonvpn-wg-confgen-${{ matrix.goos }}-${{ matrix.goarch }}
+          path: build/protonvpn-wg-confgen-${{ matrix.goos }}-${{ matrix.goarch }}${{ matrix.ext }}

protonvpn-wg-confgen/.github/workflows/release.yml

@@ -0,0 +1,37 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+permissions:
+  contents: write
+
+env:
+  GO_VERSION: "1.25.6"
+
+jobs:
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          fetch-depth: 0
+
+      - name: Set up Go
+        uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5 # v6.2.0
+        with:
+          go-version: ${{ env.GO_VERSION }}
+          cache: true
+
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@e435ccd777264be153ace6237001ef4d979d3a7a # v6.4.0
+        with:
+          distribution: goreleaser
+          version: "~> v2"
+          args: release --clean
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

protonvpn-wg-confgen/.gitignore

@@ -0,0 +1,52 @@
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool
+*.out
+
+# Go vendor directory
+vendor/
+
+# Build directory
+build/
+
+# Binary
+protonvpn-wg-confgen
+
+# IDE specific files
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# OS specific files
+.DS_Store
+Thumbs.db
+
+# Configuration files generated by the tool
+*.conf
+
+# Session files
+.protonvpn-session.json
+
+# Temporary files
+*.tmp
+*.bak
+
+# Log files
+*.log
+
+# Debug and reference libraries
+.debug-libs/
+
+# Claude Code
+.claude/
+CLAUDE.md

protonvpn-wg-confgen/.golangci.yml

@@ -0,0 +1,107 @@
+# yaml-language-server: $schema=https://golangci-lint.run/jsonschema/golangci.v2.jsonschema.json
+version: "2"
+
+linters:
+  enable:
+    # Default linters
+    - errcheck
+    - govet
+    - ineffassign
+    - staticcheck
+    - unused
+    # Code quality
+    - gocritic
+    - gocognit
+    - gocyclo
+    - revive
+    - misspell
+    - unconvert
+    - dupl
+    - prealloc
+    # Error handling
+    - nilerr
+    - errorlint
+    # Security
+    - gosec
+    # Style & formatting
+    - whitespace
+    - wastedassign
+    # Best practices
+    - exhaustive
+    - nolintlint
+    - goconst
+    - nakedret
+    - nestif
+    - bodyclose
+    - usestdlibvars
+    - copyloopvar
+    - intrange
+
+  settings:
+    revive:
+      severity: warning
+      rules:
+        - name: blank-imports
+        - name: context-as-argument
+        - name: error-return
+        - name: error-strings
+        - name: error-naming
+        - name: exported
+        - name: package-comments
+        - name: range
+        - name: receiver-naming
+        - name: indent-error-flow
+        - name: superfluous-else
+
+    gocyclo:
+      min-complexity: 15
+
+    gocognit:
+      min-complexity: 30
+
+    gocritic:
+      enabled-tags:
+        - diagnostic
+        - experimental
+        - opinionated
+        - performance
+        - style
+
+    dupl:
+      threshold: 100
+
+    goconst:
+      min-len: 3
+      min-occurrences: 3
+
+    nakedret:
+      max-func-lines: 30
+
+    nestif:
+      min-complexity: 4
+
+    errorlint:
+      errorf: true
+      asserts: true
+      comparison: true
+
+    nolintlint:
+      require-explanation: true
+      require-specific: true
+
+  exclusions:
+    paths:
+      - vendor
+
+issues:
+  max-issues-per-linter: 50
+  max-same-issues: 10
+
+run:
+  timeout: 5m
+  tests: true
+
+formatters:
+  enable:
+    - gofmt
+    - goimports

protonvpn-wg-confgen/.goreleaser.yaml

@@ -0,0 +1,76 @@
+# yaml-language-server: $schema=https://goreleaser.com/static/schema.json
+version: 2
+
+project_name: protonvpn-wg-confgen
+
+before:
+  hooks:
+    - go mod tidy
+
+builds:
+  - id: protonvpn-wg-confgen
+    main: ./cmd/protonvpn-wg
+    binary: protonvpn-wg-confgen
+    env:
+      - CGO_ENABLED=0
+    goos:
+      - linux
+      - darwin
+      - windows
+    goarch:
+      - amd64
+      - arm64
+      - arm
+    goarm:
+      - "7"
+    ignore:
+      # Windows ARM (32-bit) not commonly used
+      - goos: windows
+        goarch: arm
+      # macOS ARM (32-bit) doesn't exist
+      - goos: darwin
+        goarch: arm
+    ldflags:
+      - -s -w
+
+archives:
+  - id: default
+    formats:
+      - tar.gz
+    format_overrides:
+      - goos: windows
+        formats:
+          - zip
+    name_template: >-
+      {{ .ProjectName }}_
+      {{- .Version }}_
+      {{- .Os }}_
+      {{- .Arch }}
+      {{- if .Arm }}v{{ .Arm }}{{ end }}
+    files:
+      - README.md
+      - LICENSE
+
+checksum:
+  name_template: "checksums.txt"
+  algorithm: sha256
+
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - "^docs:"
+      - "^test:"
+      - "^ci:"
+      - "^chore:"
+      - Merge pull request
+      - Merge branch
+
+release:
+  github:
+    owner: '{{ envOrDefault "GITHUB_REPOSITORY_OWNER" "" }}'
+    name: protonvpn-wg-confgen
+  draft: false
+  prerelease: auto
+  mode: replace
+  name_template: "v{{.Version}}"

protonvpn-wg-confgen/API_REFERENCE.md

@@ -0,0 +1,149 @@
+# API Reference Implementation
+
+This project's API integration was developed by reverse-engineering ProtonVPN's authentication and VPN APIs. The implementation is based on patterns from these official Proton libraries:
+
+## Authentication (SRP Protocol)
+- **[ProtonMail/proton-python-client](https://github.com/ProtonMail/proton-python-client)** - Python implementation of Proton's SRP authentication
+  - Reference for: `/auth/info`, `/auth`, `/auth/2fa`, `/auth/refresh` endpoints
+  - SRP protocol implementation patterns
+- **[ProtonMail/go-srp](https://github.com/ProtonMail/go-srp)** - Go SRP library (direct dependency)
+
+## VPN API
+- **[ProtonVPN/python-proton-vpn-api-core](https://github.com/ProtonVPN/python-proton-vpn-api-core)** - Official Python VPN API client
+  - Reference for: `/vpn/v1/certificate`, `/vpn/v1/logicals`, `/vpn/v1/sessions` endpoints
+  - Server filtering and selection patterns
+  - Certificate request format (`Duration`, `Features`)
+
+## Key Generation
+- **[ProtonVPN/go-vpn-lib](https://github.com/ProtonVPN/go-vpn-lib)** - Ed25519 to X25519 key conversion (direct dependency)
+
+## Client Version
+- **[ProtonVPN/proton-vpn-gtk-app](https://github.com/ProtonVPN/proton-vpn-gtk-app)** - Official Linux client
+  - Source for `x-pm-appversion` header value (fetched dynamically at build time)
+
+## API Endpoints Used
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `/core/v4/auth/info` | POST | Get SRP authentication parameters |
+| `/core/v4/auth` | POST | Authenticate with SRP proofs |
+| `/core/v4/auth/2fa` | POST | Submit 2FA code for session upgrade |
+| `/auth/refresh` | POST | Refresh session tokens |
+| `/vpn/v1/certificate` | POST | Generate WireGuard certificate |
+| `/vpn/v1/logicals` | GET | List available VPN servers |
+
+## Certificate Request Format
+
+The certificate request to `/vpn/v1/certificate` uses the following format:
+
+```json
+{
+  "ClientPublicKey": "<PEM-encoded public key>",
+  "ClientPublicKeyMode": "EC",
+  "Mode": "persistent",
+  "DeviceName": "<device name>",
+  "Duration": "<duration in minutes> min",
+  "Features": {
+    "NetShieldLevel": 0,
+    "RandomNAT": false,
+    "PortForwarding": false,
+    "SplitTCP": true
+  }
+}
+```
+
+### Feature Keys
+
+| Key | Type | Description |
+|-----|------|-------------|
+| `NetShieldLevel` | int | NetShield ad/malware blocking (0=off, 1=malware, 2=ads+malware) |
+| `RandomNAT` | bool | Moderate NAT / Random NAT for gaming |
+| `PortForwarding` | bool | Port forwarding support |
+| `SplitTCP` | bool | VPN Accelerator (performance optimization) |
+
+## API Response Codes
+
+**Official sources:**
+- [ProtonMail/protoncore_android - ResponseCodes.kt](https://github.com/ProtonMail/protoncore_android/blob/main/network/domain/src/main/kotlin/me/proton/core/network/domain/ResponseCodes.kt) - Kotlin constants (authoritative)
+- [ProtonMail/proton-python-client - README.md](https://github.com/ProtonMail/proton-python-client#error-handling) - Python client error handling
+- [ProtonMail/proton-python-client - api.py](https://github.com/ProtonMail/proton-python-client/blob/master/proton/api.py) - Python API implementation
+
+### Success Codes
+| Code | Constant | Meaning |
+|------|----------|---------|
+| 1000 | OK | Success |
+| 1001 | - | Success (multi-status) |
+
+### Authentication Errors
+| Code | Constant | Meaning |
+|------|----------|---------|
+| 8002 | PASSWORD_WRONG | Incorrect password |
+| 8100 | AUTH_SWITCH_TO_SSO | Switch to SSO authentication |
+| 8101 | AUTH_SWITCH_TO_SRP | Switch to SRP authentication |
+| 9001 | HUMAN_VERIFICATION_REQUIRED | CAPTCHA/human verification required |
+| 9002 | DEVICE_VERIFICATION_REQUIRED | Device verification required |
+| 9101 | SCOPE_REAUTH_LOCKED | Scope re-authentication locked |
+| 9102 | SCOPE_REAUTH_PASSWORD | Scope re-authentication requires password |
+
+### Account Errors
+| Code | Constant | Meaning |
+|------|----------|---------|
+| 10001 | ACCOUNT_FAILED_GENERIC | Generic account failure |
+| 10002 | ACCOUNT_DELETED | Account has been deleted |
+| 10003 | ACCOUNT_DISABLED | Account has been disabled |
+
+### Version Errors
+| Code | Constant | Meaning |
+|------|----------|---------|
+| 5003 | APP_VERSION_BAD | App version no longer supported |
+| 5005 | API_VERSION_INVALID | API version invalid |
+| 5099 | APP_VERSION_NOT_SUPPORTED_FOR_EXTERNAL_ACCOUNTS | App version not supported for external accounts |
+
+### Other Errors
+| Code | Constant | Meaning |
+|------|----------|---------|
+| 6001 | BODY_PARSE_FAILURE | Request body parse failure |
+| 12081 | USER_CREATE_NAME_INVALID | Invalid username during creation |
+| 12087 | USER_CREATE_TOKEN_INVALID | Invalid token during user creation |
+
+### VPN-Specific Codes (observed, not in official docs)
+| Code | Meaning | Notes |
+|------|---------|-------|
+| 9100 | 2FA required for VPN | VPN certificate endpoint requires 2FA-authenticated session |
+| 10013 | Mailbox password required | Legacy 2-password mode (proton-python-client says "RefreshToken invalid") |
+
+**Note:** Codes 9100 and 10013 were observed during VPN operations but are not documented in the official protoncore_android library. Their meanings may vary by context.
+
+## Required Headers
+
+All authenticated requests require these headers:
+
+```
+Authorization: Bearer <access_token>
+x-pm-uid: <session_uid>
+x-pm-appversion: linux-vpn@X.Y.Z
+User-Agent: ProtonVPN/X.Y.Z (Linux; Ubuntu)
+Content-Type: application/json
+```
+
+**Important**: Using a web client version (like `web-vpn-settings@X.Y.Z`) may trigger CAPTCHA challenges. Always use the Linux client version format.
+
+## Token Refresh
+
+The token refresh endpoint expects:
+
+```json
+{
+  "ResponseType": "token",
+  "GrantType": "refresh_token",
+  "RefreshToken": "<refresh_token>",
+  "RedirectURI": "http://protonmail.ch"
+}
+```
+
+## Local Reference Libraries
+
+For debugging and verification, reference implementations are cloned in `.debug-libs/`:
+- `proton-python-client` - SRP authentication reference
+- `python-proton-vpn-api-core` - VPN API reference
+- `proton-vpn-gtk-app` - Linux client reference

protonvpn-wg-confgen/LICENSE

@@ -0,0 +1,674 @@
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+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
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+the Program, the only way you could satisfy both those terms and this
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+  13. Use with the GNU Affero General Public License.
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+  Each version is given a distinguishing version number.  If the
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+  If the Program specifies that a proxy can decide which future
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+  17. Interpretation of Sections 15 and 16.
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+  If the disclaimer of warranty and limitation of liability provided
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+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
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+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
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+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

protonvpn-wg-confgen/Makefile

@@ -0,0 +1,89 @@
+.PHONY: build build-all clean test fmt vet lint install vendor run dev show-version
+
+BINARY_NAME=protonvpn-wg-confgen
+BUILD_DIR=build
+CMD_DIR=cmd/protonvpn-wg
+MODULE=protonvpn-wg-confgen
+
+# Fetch latest ProtonVPN Linux client version from GitHub (with fallback)
+PROTON_VERSION_URL=https://raw.githubusercontent.com/ProtonVPN/proton-vpn-gtk-app/stable/versions.yml
+PROTON_VERSION ?= $(shell curl -sf "$(PROTON_VERSION_URL)" 2>/dev/null | head -1 | cut -d' ' -f2 || echo "4.13.1")
+
+# ldflags to inject version at build time
+LDFLAGS=-ldflags "-X '$(MODULE)/internal/constants.AppVersion=linux-vpn@$(PROTON_VERSION)' \
+                  -X '$(MODULE)/internal/constants.UserAgent=ProtonVPN/$(PROTON_VERSION) (Linux; Ubuntu)'"
+
+# Build the binary
+build:
+	@echo "Building $(BINARY_NAME) with ProtonVPN client version $(PROTON_VERSION)..."
+	@mkdir -p $(BUILD_DIR)
+	@go build $(LDFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME) $(CMD_DIR)/main.go
+
+# Build for multiple platforms
+build-all:
+	@echo "Building for multiple platforms with ProtonVPN client version $(PROTON_VERSION)..."
+	@mkdir -p $(BUILD_DIR)
+	@echo "  Linux amd64..."
+	@GOOS=linux GOARCH=amd64 go build $(LDFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME)-linux-amd64 $(CMD_DIR)/main.go
+	@echo "  Linux arm64..."
+	@GOOS=linux GOARCH=arm64 go build $(LDFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME)-linux-arm64 $(CMD_DIR)/main.go
+	@echo "  Linux arm..."
+	@GOOS=linux GOARCH=arm go build $(LDFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME)-linux-arm $(CMD_DIR)/main.go
+	@echo "  macOS amd64..."
+	@GOOS=darwin GOARCH=amd64 go build $(LDFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME)-darwin-amd64 $(CMD_DIR)/main.go
+	@echo "  macOS arm64..."
+	@GOOS=darwin GOARCH=arm64 go build $(LDFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME)-darwin-arm64 $(CMD_DIR)/main.go
+	@echo "  Windows amd64..."
+	@GOOS=windows GOARCH=amd64 go build $(LDFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME)-windows-amd64.exe $(CMD_DIR)/main.go
+	@echo "  Windows arm64..."
+	@GOOS=windows GOARCH=arm64 go build $(LDFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME)-windows-arm64.exe $(CMD_DIR)/main.go
+	@echo "Done!"
+
+# Clean build artifacts
+clean:
+	@echo "Cleaning..."
+	@rm -rf $(BUILD_DIR)
+	@rm -f $(BINARY_NAME)
+
+# Run tests
+test:
+	@echo "Running tests..."
+	@go test -v ./...
+
+# Format code
+fmt:
+	@echo "Formatting code..."
+	@go fmt ./...
+
+# Run go vet
+vet:
+	@echo "Running go vet..."
+	@go vet ./...
+
+# Run golangci-lint (requires golangci-lint to be installed)
+lint:
+	@echo "Running linter..."
+	@golangci-lint run
+
+# Install the binary
+install: build
+	@echo "Installing $(BINARY_NAME)..."
+	@cp $(BUILD_DIR)/$(BINARY_NAME) $(GOPATH)/bin/$(BINARY_NAME)
+
+# Update vendor directory
+vendor:
+	@echo "Updating vendor..."
+	@go mod vendor
+
+# Run the application
+run: build
+	@./$(BUILD_DIR)/$(BINARY_NAME) $(ARGS)
+
+# Development build with race detector
+dev:
+	@echo "Building with race detector and ProtonVPN client version $(PROTON_VERSION)..."
+	@go build -race $(LDFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME)-dev $(CMD_DIR)/main.go
+
+# Show current ProtonVPN version that would be used
+show-version:
+	@echo "ProtonVPN client version: $(PROTON_VERSION)"

protonvpn-wg-confgen/README.md

@@ -0,0 +1,326 @@
+# ProtonVPN WireGuard Config Generate
+
+[![CI](https://github.com/hatemosphere/protonvpn-wg-confgen/actions/workflows/ci.yml/badge.svg)](https://github.com/hatemosphere/protonvpn-wg-confgen/actions/workflows/ci.yml)
+[![Release](https://img.shields.io/github/v/release/hatemosphere/protonvpn-wg-confgen?include_prereleases)](https://github.com/hatemosphere/protonvpn-wg-confgen/releases/latest)
+[![Go Report Card](https://goreportcard.com/badge/github.com/hatemosphere/protonvpn-wg-confgen)](https://goreportcard.com/report/github.com/hatemosphere/protonvpn-wg-confgen)
+[![License: GPL-3.0](https://img.shields.io/badge/License-GPL--3.0-blue.svg)](https://www.gnu.org/licenses/gpl-3.0)
+
+A Go program that generates WireGuard configuration files for ProtonVPN servers with automatic selection of the best servers from specified countries with support of generic filters.
+
+## Motivation
+
+I wanted to automatically rotate VPN servers on my private HTPC Linux host running WireGuard, and since I'm already paying for a Proton bundle subscription, why not just use theirs? Unfortunately, as of the time of writing, they didn't have a good programmatic headless way to generate WireGuard profiles, so I did my research and reverse-engineered their APIs (which was a pain in the butt) and created this. The idea is to run this code as a daemon and restart the WireGuard client on profile file change.
+
+## Features
+
+- Authenticates with ProtonVPN using username/password
+- Opnionally persists and refreshes login session, to function in headless mode after entering password once
+- Supports 2FA authentication (TOTP only, no FIDO2/security keys)
+- Creates persistent WireGuard configurations (visible in ProtonVPN dashboard)
+- Automatically selects the best server (highest score, lowest load) from specified countries
+- Supports both Free tier and paid tier servers (Plus and ProtonMail)
+- Filters servers by features (P2P support, Secure Core)
+- Generates WireGuard configuration files
+- Supports VPN accelerator feature
+- IPv6 support
+
+## Installation
+
+1. Clone the repository:
+```bash
+git clone https://github.com/hatemosphere/protonvpn-wg-confgen
+cd protonvpn-wg-confgen
+```
+
+2. Build the program:
+```bash
+make build
+```
+
+Or manually with Go:
+```bash
+go build -o build/protonvpn-wg-confgen cmd/protonvpn-wg/main.go
+```
+
+## Usage
+
+```bash
+./build/protonvpn-wg-confgen -username <username> -countries <country-codes> [options]
+```
+
+### Options
+
+- `-username`: ProtonVPN username (optional, will prompt if not provided)
+- `-countries`: Comma-separated list of country codes (e.g., US,NL,CH) **[Required]**
+- `-output`: Output WireGuard configuration file (default: protonvpn.conf)
+- `-ipv6`: Enable IPv6 support (default: false)
+- `-dns`: Comma-separated list of DNS servers (defaults based on IPv6 setting)
+- `-allowed-ips`: Comma-separated list of allowed IPs (defaults based on IPv6 setting)
+- `-accelerator`: Enable VPN accelerator (default: true)
+- `-api-url`: ProtonVPN API URL (default: https://vpn-api.proton.me)
+- `-p2p-only`: Use only P2P-enabled servers (default: true)
+- `-secure-core`: Use only Secure Core servers for multi-hop VPN (default: false)
+- `-free-only`: Use only Free tier servers (tier 0) (default: false)
+- `-device-name`: Device name for WireGuard config (auto-generated if empty)
+- `-debug`: Enable debug output showing all filtered servers (default: false)
+- `-duration`: Certificate duration (default: 365d). Examples: 30m, 24h, 7d, 1h30m. Maximum: 365d
+- `-clear-session`: Clear saved session and force re-authentication
+- `-no-session`: Don't save or use session persistence
+- `-force-refresh`: Force session refresh even if not close to expiration (requires re-authentication)
+- `-session-duration`: Session cache duration (default: 0 = use API expiration). Examples: 12h, 24h, 7d. Max: 30d
+
+### Examples
+
+1. Generate config for best P2P server in US or Netherlands:
+```bash
+./build/protonvpn-wg-confgen -username myusername -countries US,NL
+```
+
+2. Generate config with custom DNS and output file:
+```bash
+./build/protonvpn-wg-confgen -username myusername -countries CH,DE -dns 1.1.1.1,8.8.8.8 -output switzerland.conf
+```
+
+3. Disable VPN accelerator:
+```bash
+./build/protonvpn-wg-confgen -username myusername -countries US -accelerator=false
+```
+
+4. Generate config with 30-day duration:
+```bash
+./build/protonvpn-wg-confgen -username myusername -countries US -duration 30d
+```
+
+5. Generate config without saving session (always prompt for password):
+```bash
+./build/protonvpn-wg-confgen -username myusername -countries US -no-session
+```
+
+6. Use session with 24-hour expiration:
+```bash
+./build/protonvpn-wg-confgen -username myusername -countries US -session-duration 24h
+```
+
+7. Enable IPv6 support:
+```bash
+./build/protonvpn-wg-confgen -username myusername -countries US -ipv6
+```
+
+8. Use Secure Core servers for enhanced privacy:
+```bash
+./build/protonvpn-wg-confgen -username myusername -countries NL,US -secure-core
+```
+
+9. Debug mode to see all available servers:
+```bash
+./build/protonvpn-wg-confgen -username myusername -countries US -debug
+```
+
+10. Use Free tier servers only:
+```bash
+./build/protonvpn-wg-confgen -username myusername -countries US,NL -free-only
+```
+
+## IPv6 Support
+
+By default, the tool generates IPv4-only configurations. When you enable IPv6 with the `-ipv6` flag:
+
+- **Interface Address**: Both IPv4 (10.2.0.2/32) and IPv6 (2a07:b944::2:2/128) addresses are assigned
+- **DNS Servers**: IPv4 DNS (10.2.0.1) and IPv6 DNS (2a07:b944::2:1) - both ProtonVPN's internal DNS servers
+- **Allowed IPs**: Both IPv4 (0.0.0.0/0) and IPv6 (::/0) routes are included
+
+You can override the defaults by explicitly specifying `-dns` and `-allowed-ips` flags.
+
+## Secure Core
+
+Secure Core is ProtonVPN's premium feature that routes your traffic through multiple servers before leaving the VPN network:
+
+- First hop: Through secure servers in privacy-friendly countries (Switzerland, Iceland, Sweden)
+- Second hop: To your chosen destination country
+- Provides additional protection against network-based attacks
+- Use the `-secure-core` flag to enable this feature
+- Note: Secure Core servers may have higher latency due to the multi-hop routing
+
+**Important Notes:**
+- Secure Core servers don't support P2P, so P2P filtering is automatically disabled when using `-secure-core`
+- The country filter always applies to **exit countries** - where your traffic appears to come from
+- Server names show both entry and exit countries (e.g., "IS-NL#1" = Iceland → Netherlands)
+- Entry countries for Secure Core are always privacy-friendly: Switzerland (CH), Iceland (IS), Sweden (SE)
+
+## Authentication
+
+**Important:** This tool only works with Proton accounts configured in [Single Password Mode](https://proton.me/support/single-password). This is the default for all new Proton accounts. If your account uses the legacy 2-password mode (separate login and mailbox passwords), you'll need to switch to single password mode first.
+
+The program supports the following authentication methods:
+
+1. **Username/Password**: Enter your ProtonVPN credentials
+2. **2FA (TOTP only)**: If enabled, you'll be prompted for your 6-digit authenticator code
+
+**Important 2FA Limitation:** This tool only supports **TOTP-based 2FA** (authenticator apps like Google Authenticator, Authy, 1Password, etc.). **FIDO2/WebAuthn security keys are NOT supported** because they require browser/platform APIs for the challenge-response protocol.
+
+If you use a security key as your only 2FA method, you have two options:
+- Add TOTP as an additional 2FA method in your [Proton account security settings](https://account.proton.me/u/0/vpn/account-password)
+- Use a security key that also supports TOTP (like YubiKey with Yubico Authenticator)
+
+### Session Persistence
+
+The program saves your authentication session to avoid re-entering credentials:
+- Sessions are stored in `~/.protonvpn-session.json` with secure permissions (0600)
+- ProtonVPN sessions expire after 30 days (from API `ExpiresIn` field)
+- Session duration is configurable with `-session-duration` (default: 0 = use API's 30 days)
+- Custom durations are capped at the API's expiration time
+- Sessions show time until expiration when reused
+- Sessions are automatically verified before use
+- Sessions automatically refresh when less than 7 days remain
+- Use `-clear-session` flag to force re-authentication
+- Use `-force-refresh` flag to force refresh even if not expiring soon
+- Use `-no-session` flag to disable session persistence entirely
+- Sessions are user-specific and won't be used for different usernames
+
+## Using the Generated Configuration
+
+Once you have the WireGuard configuration file, you can use it with any WireGuard client:
+
+### Linux
+```bash
+sudo wg-quick up ./protonvpn.conf
+```
+
+### macOS (with WireGuard installed)
+```bash
+sudo wg-quick up ./protonvpn.conf
+```
+
+### Windows/GUI clients
+Import the configuration file into your WireGuard client.
+
+## Server Tier Support
+
+By default, the tool excludes Free tier servers and only uses paid tier servers (Plus and ProtonMail):
+- **Free tier (tier 0)**: Available with `-free-only` flag. Limited server selection, no P2P support
+- **Plus tier (tier 2)**: Default. Full feature support including P2P and Secure Core
+- **ProtonMail tier (tier 3)**: Default. Included with Proton bundle subscriptions
+
+**Important Notes:**
+- When using `-free-only`, P2P filtering is automatically disabled since Free servers don't support P2P
+- Free tier servers have limited availability and may have higher load
+- Secure Core requires Plus or higher subscription
+
+## Requirements
+
+- Go 1.25 or higher
+- ProtonVPN account (Free tier or paid subscription)
+
+## Security Notes
+
+- The program generates a new WireGuard private key for each run
+- Configuration files contain sensitive information and are saved with 0600 permissions
+- Never share your WireGuard configuration files
+- Persistent configurations appear in your ProtonVPN dashboard and can be revoked there
+- Certificates are valid for the specified duration (default: 365 days, max: 365 days)
+
+## Project Structure
+
+```
+.
+├── cmd/
+│   └── protonvpn-wg/      # Main application entry point
+│       └── main.go        # CLI entry point
+├── internal/              # Private application code
+│   ├── api/              # API types and data structures
+│   │   └── types.go      # ProtonVPN API response types
+│   ├── auth/             # Authentication logic
+│   │   ├── auth.go       # SRP authentication implementation
+│   │   ├── errors.go     # Custom error types
+│   │   └── session.go    # Session management and refresh
+│   ├── config/           # Configuration handling
+│   │   ├── flags.go      # Command-line flag parsing
+│   │   └── types.go      # Config struct and validation
+│   ├── constants/        # Application constants
+│   │   ├── api.go        # API endpoints and headers
+│   │   ├── defaults.go   # Default configuration values
+│   │   ├── session.go    # Session-related constants
+│   │   └── wireguard.go  # WireGuard network constants
+│   └── vpn/              # VPN functionality
+│       ├── client.go     # Certificate generation
+│       └── servers.go    # Server selection logic
+├── pkg/                  # Public packages
+│   ├── timeutil/         # Time and duration utilities
+│   │   ├── formatter.go  # Duration formatting
+│   │   └── parser.go     # Duration parsing
+│   ├── validation/       # Input validation
+│   │   └── validation.go # Username and country code validation
+│   └── wireguard/        # WireGuard configuration
+│       ├── config.go     # Config file generation
+│       └── config_test.go # Config generation tests
+├── vendor/               # Vendored dependencies
+├── Makefile              # Build automation
+├── go.mod                # Go module definition
+├── go.sum                # Module checksums
+└── README.md             # This file
+```
+
+## Development
+
+```bash
+# Format code
+make fmt
+
+# Run tests
+make test
+
+# Run linter (requires golangci-lint)
+make lint
+
+# Build for multiple platforms
+make build-all
+
+# Clean build artifacts
+make clean
+```
+
+## Troubleshooting
+
+### CAPTCHA Verification Required (Error 9001)
+
+If you encounter "CAPTCHA verification required" error:
+
+1. **Login via ProtonVPN website first**: This can help establish your account as legitimate
+2. **Try from a different IP**: VPN or residential IPs may work better than datacenter IPs
+3. **Wait and retry**: Sometimes waiting a few hours helps
+4. **Use saved sessions**: Once authenticated, sessions are saved to avoid repeated CAPTCHA challenges
+
+### App Version Errors (Error 5003)
+
+If you see "This version of the app is no longer supported":
+- The app version is automatically fetched from ProtonVPN's GitHub at build time
+- Rebuild with `make build` to get the latest version
+- Override manually if needed: `make build PROTON_VERSION=X.Y.Z`
+- Check current version: `make show-version`
+
+### Two-Password Mode Error (Code 10013)
+
+If you see "unexpected mailbox password request - account might still be in 2-password mode":
+- Your Proton account is using the legacy 2-password mode (separate login and mailbox passwords)
+- This tool only supports [Single Password Mode](https://proton.me/support/single-password)
+- To switch: Go to Proton account settings → Security → Password mode → Switch to single password
+- Note: Single password mode is the default for all new Proton accounts since ~2020
+
+### 2FA Required for VPN (Error 9100)
+
+If authentication succeeds but you get error 9100 when getting the VPN certificate:
+- Your account has 2FA enabled, but ProtonVPN's device trust mechanism allowed login without 2FA
+- The VPN certificate endpoint requires a session that was authenticated with 2FA
+- **Solution**: Run with `-clear-session` flag to force re-authentication, which should prompt for 2FA
+- If 2FA prompt still doesn't appear, try from a different IP/network to bypass device trust
+- This can also occur if your account uses 2-password mode (see error 10013 above)
+
+## API Reference
+
+For detailed API documentation including endpoints, request formats, response codes, and reference implementations, see [API_REFERENCE.md](API_REFERENCE.md).
+
+## License
+
+This project is licensed under the [GNU General Public License v3.0](LICENSE).
+
+This is required because the project uses [ProtonVPN/go-vpn-lib](https://github.com/ProtonVPN/go-vpn-lib) which is licensed under GPL-3.0.

protonvpn-wg-confgen/cmd/protonvpn-wg/main.go

@@ -0,0 +1,104 @@
+// Package main provides the command-line interface for generating ProtonVPN WireGuard configurations.
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"protonvpn-wg-confgen/internal/api"
+	"protonvpn-wg-confgen/internal/auth"
+	"protonvpn-wg-confgen/internal/config"
+	"protonvpn-wg-confgen/internal/vpn"
+	"protonvpn-wg-confgen/pkg/wireguard"
+
+	"github.com/ProtonVPN/go-vpn-lib/ed25519"
+)
+
+func main() {
+	if err := run(); err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	// Parse configuration
+	cfg, err := config.Parse()
+	if err != nil {
+		config.PrintUsage()
+		return err
+	}
+
+	// Authenticate
+	authClient := auth.NewClient(cfg)
+	session, err := authClient.Authenticate()
+	if err != nil {
+		return fmt.Errorf("authentication failed: %w", err)
+	}
+	fmt.Println("Authentication successful!")
+
+	// Generate key pair
+	keyPair, err := ed25519.NewKeyPair()
+	if err != nil {
+		return fmt.Errorf("failed to generate key pair: %w", err)
+	}
+	cfg.ClientPrivateKey = keyPair.ToX25519Base64()
+
+	// Create VPN client
+	vpnClient := vpn.NewClient(cfg, session)
+
+	// Get VPN certificate
+	vpnInfo, err := vpnClient.GetCertificate(keyPair)
+	if err != nil {
+		return fmt.Errorf("failed to get VPN certificate: %w", err)
+	}
+
+	// Get server list
+	servers, err := vpnClient.GetServers()
+	if err != nil {
+		return fmt.Errorf("failed to get servers: %w", err)
+	}
+
+	// Select best server
+	selector := vpn.NewServerSelector(cfg)
+	server, err := selector.SelectBest(servers)
+	if err != nil {
+		return err
+	}
+
+	// Build feature list string
+	features := api.GetFeatureNames(server.Features)
+	featureStr := ""
+	if len(features) > 0 {
+		featureStr = fmt.Sprintf(", Features: %s", strings.Join(features, ", "))
+	}
+
+	fmt.Printf("Selected server: %s (Country: %s, City: %s, Tier: %s, Load: %d%%, Score: %.2f, Servers: %d%s)\n",
+		server.Name, server.ExitCountry, server.City, api.GetTierName(server.Tier),
+		server.Load, server.Score, len(server.Servers), featureStr)
+
+	// Get best physical server
+	physicalServer := vpn.GetBestPhysicalServer(server)
+	if physicalServer == nil {
+		return fmt.Errorf("no physical servers available")
+	}
+
+	// Generate WireGuard configuration
+	generator := wireguard.NewConfigGenerator(cfg)
+	if err := generator.Generate(server, physicalServer, cfg.ClientPrivateKey); err != nil {
+		return fmt.Errorf("failed to generate WireGuard config: %w", err)
+	}
+
+	fmt.Printf("WireGuard configuration written to: %s\n", cfg.OutputFile)
+
+	// Note about persistence
+	if vpnInfo.DeviceName != "" {
+		fmt.Printf("Device name: %s (visible in ProtonVPN dashboard)\n", vpnInfo.DeviceName)
+	}
+
+	// Show final success
+	fmt.Printf("\nSuccessfully generated config for %s\n", server.ExitCountry)
+
+	return nil
+}

protonvpn-wg-confgen/go.mod

@@ -0,0 +1,19 @@
+module protonvpn-wg-confgen
+
+go 1.25.6
+
+require (
+	github.com/ProtonMail/go-srp v0.0.7
+	github.com/ProtonVPN/go-vpn-lib v0.0.0-20260122061324-3e8ad1be9349
+	golang.org/x/term v0.39.0
+)
+
+require (
+	github.com/ProtonMail/bcrypt v0.0.0-20211005172633-e235017c1baf // indirect
+	github.com/ProtonMail/go-crypto v1.3.0 // indirect
+	github.com/cloudflare/circl v1.6.2 // indirect
+	github.com/cronokirby/saferith v0.33.0 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	golang.org/x/crypto v0.47.0 // indirect
+	golang.org/x/sys v0.40.0 // indirect
+)

protonvpn-wg-confgen/go.sum

@@ -0,0 +1,68 @@
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+github.com/ProtonMail/bcrypt v0.0.0-20211005172633-e235017c1baf h1:yc9daCCYUefEs69zUkSzubzjBbL+cmOXgnmt9Fyd9ug=
+github.com/ProtonMail/bcrypt v0.0.0-20211005172633-e235017c1baf/go.mod h1:o0ESU9p83twszAU8LBeJKFAAMX14tISa0yk4Oo5TOqo=
+github.com/ProtonMail/go-crypto v0.0.0-20230321155629-9a39f2531310/go.mod h1:8TI4H3IbrackdNgv+92dI+rhpCaLqM0IfpgCgenFvRE=
+github.com/ProtonMail/go-crypto v1.3.0 h1:ILq8+Sf5If5DCpHQp4PbZdS1J7HDFRXz/+xKBiRGFrw=
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protonvpn-wg-confgen/internal/api/types.go

@@ -0,0 +1,165 @@
+// Package api defines the data structures for ProtonVPN API responses.
+package api
+
+// AuthInfoResponse represents the response from the auth info endpoint
+type AuthInfoResponse struct {
+	Code            int    `json:"Code"`
+	Version         int    `json:"Version"`
+	Modulus         string `json:"Modulus"`
+	ServerEphemeral string `json:"ServerEphemeral"`
+	Salt            string `json:"Salt"`
+	SRPSession      string `json:"SRPSession"`
+	TwoFA           struct {
+		Enabled int `json:"Enabled"`
+		TOTP    int `json:"TOTP"`
+	} `json:"2FA"`
+}
+
+// AuthRequest represents the authentication request payload
+type AuthRequest struct {
+	Username        string `json:"Username"`
+	ClientEphemeral string `json:"ClientEphemeral"`
+	ClientProof     string `json:"ClientProof"`
+	SRPSession      string `json:"SRPSession"`
+	TwoFactorCode   string `json:"TwoFactorCode,omitempty"`
+}
+
+// Session represents a ProtonVPN session
+type Session struct {
+	Code         int      `json:"Code"`
+	AccessToken  string   `json:"AccessToken"`
+	RefreshToken string   `json:"RefreshToken"`
+	TokenType    string   `json:"TokenType"`
+	Scopes       []string `json:"Scopes"`
+	UID          string   `json:"UID"`
+	UserID       string   `json:"UserID"`
+	EventID      string   `json:"EventID"`
+	ServerProof  string   `json:"ServerProof"`
+	PasswordMode int      `json:"PasswordMode"`
+	ExpiresIn    int      `json:"ExpiresIn"` // Session expiration in seconds
+	TwoFA        struct {
+		Enabled int `json:"Enabled"`
+		TOTP    int `json:"TOTP"`
+	} `json:"2FA"`
+}
+
+// VPNInfo represents VPN certificate information
+type VPNInfo struct {
+	Code                 int    `json:"Code"`
+	Error                string `json:"Error,omitempty"`
+	SerialNumber         string `json:"SerialNumber"`
+	ClientKeyFingerprint string `json:"ClientKeyFingerprint"`
+	ClientKey            string `json:"ClientKey"`
+	Certificate          string `json:"Certificate"`
+	ExpirationTime       int64  `json:"ExpirationTime"`
+	RefreshTime          int64  `json:"RefreshTime"`
+	Mode                 string `json:"Mode"`
+	DeviceName           string `json:"DeviceName"`
+	ServerPublicKeyMode  string `json:"ServerPublicKeyMode"`
+	ServerPublicKey      string `json:"ServerPublicKey"`
+	Features             struct {
+		Bouncing       bool `json:"bouncing"`
+		ModerateNAT    bool `json:"moderate-nat"`
+		NetshieldLevel int  `json:"netshield-level"`
+		PortForwarding bool `json:"port-forwarding"`
+		VPNAccelerator bool `json:"vpn-accelerator"`
+	} `json:"Features"`
+}
+
+// LogicalServer represents a ProtonVPN logical server
+type LogicalServer struct {
+	ID           string           `json:"ID"`
+	Name         string           `json:"Name"`
+	EntryCountry string           `json:"EntryCountry"`
+	ExitCountry  string           `json:"ExitCountry"`
+	Domain       string           `json:"Domain"`
+	Tier         int              `json:"Tier"`
+	Features     int              `json:"Features"`
+	Region       string           `json:"Region"`
+	City         string           `json:"City"`
+	Score        float64          `json:"Score"`
+	Load         int              `json:"Load"`
+	Status       int              `json:"Status"`
+	Servers      []PhysicalServer `json:"Servers"`
+	HostCountry  string           `json:"HostCountry"`
+	Location     struct {
+		Lat  float64 `json:"Lat"`
+		Long float64 `json:"Long"`
+	} `json:"Location"`
+}
+
+// PhysicalServer represents a physical VPN server
+type PhysicalServer struct {
+	ID                 string `json:"ID"`
+	EntryIP            string `json:"EntryIP"`
+	ExitIP             string `json:"ExitIP"`
+	Domain             string `json:"Domain"`
+	Status             int    `json:"Status"`
+	Label              string `json:"Label"`
+	X25519PublicKey    string `json:"X25519PublicKey"`
+	Generation         int    `json:"Generation"`
+	ServicesDownReason string `json:"ServicesDownReason"`
+}
+
+// LogicalsResponse represents the response from the logicals endpoint
+type LogicalsResponse struct {
+	Code           int             `json:"Code"`
+	LogicalServers []LogicalServer `json:"LogicalServers"`
+}
+
+// Server feature constants
+const (
+	FeatureSecureCore = 1
+	FeatureTor        = 2
+	FeatureP2P        = 4
+	FeatureStreaming  = 8
+	FeatureIPv6       = 16
+)
+
+// Server tier constants
+const (
+	TierFree = 0
+	TierPlus = 2
+	TierPM   = 3
+)
+
+// Password mode constants
+const (
+	PasswordModeSingle = 1
+	PasswordModeTwo    = 2
+)
+
+// GetTierName returns a human-readable name for the server tier
+func GetTierName(tier int) string {
+	switch tier {
+	case TierFree:
+		return "Free"
+	case TierPlus:
+		return "Plus"
+	case TierPM:
+		return "ProtonMail"
+	default:
+		return "Unknown"
+	}
+}
+
+// GetFeatureNames returns a list of enabled features for a server
+func GetFeatureNames(features int) []string {
+	var result []string
+	if features&FeatureSecureCore != 0 {
+		result = append(result, "SecureCore")
+	}
+	if features&FeatureTor != 0 {
+		result = append(result, "Tor")
+	}
+	if features&FeatureP2P != 0 {
+		result = append(result, "P2P")
+	}
+	if features&FeatureStreaming != 0 {
+		result = append(result, "Streaming")
+	}
+	if features&FeatureIPv6 != 0 {
+		result = append(result, "IPv6")
+	}
+	return result
+}

protonvpn-wg-confgen/internal/auth/auth.go

@@ -0,0 +1,503 @@
+// Package auth handles ProtonVPN authentication using the SRP protocol.
+package auth
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/tls"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"protonvpn-wg-confgen/internal/api"
+	"protonvpn-wg-confgen/internal/config"
+	"protonvpn-wg-confgen/internal/constants"
+	"protonvpn-wg-confgen/pkg/timeutil"
+
+	"github.com/ProtonMail/go-srp"
+	"golang.org/x/term"
+)
+
+// Client handles ProtonVPN authentication
+type Client struct {
+	config       *config.Config
+	httpClient   *http.Client
+	sessionStore *SessionStore
+}
+
+// NewClient creates a new authentication client
+func NewClient(cfg *config.Config) *Client {
+	return &Client{
+		config:       cfg,
+		sessionStore: NewSessionStore(),
+		httpClient: &http.Client{
+			Timeout: 30 * time.Second,
+			Transport: &http.Transport{
+				TLSClientConfig: &tls.Config{
+					InsecureSkipVerify: false,
+					MinVersion:         tls.VersionTLS12,
+				},
+			},
+		},
+	}
+}
+
+// handleSessionRefresh attempts to refresh a session and save it if successful
+func (c *Client) handleSessionRefresh(savedSession *api.Session, reason string) (*api.Session, error) {
+	fmt.Println(reason)
+	refreshedSession, err := RefreshSession(c.httpClient, c.config.APIURL, savedSession)
+	if err != nil {
+		fmt.Printf("Token refresh failed: %v\n", err)
+		fmt.Println("Re-authenticating with password...")
+		fmt.Println("(Your trusted device status for MFA will be preserved)")
+		_ = c.sessionStore.Delete()
+		return nil, err
+	}
+
+	fmt.Println("Session refreshed successfully!")
+	// Check if refresh token was rotated
+	if savedSession.RefreshToken != refreshedSession.RefreshToken {
+		fmt.Println("Refresh token was rotated")
+	}
+
+	// Save the refreshed session
+	if !c.config.NoSession {
+		sessionDuration, _ := timeutil.ParseSessionDuration(c.config.SessionDuration)
+		if err := c.sessionStore.Save(refreshedSession, c.config.Username, sessionDuration); err != nil {
+			fmt.Printf("Warning: Failed to save refreshed session: %v\n", err)
+		}
+	}
+
+	return refreshedSession, nil
+}
+
+// tryExistingSession attempts to use an existing saved session
+func (c *Client) tryExistingSession() (*api.Session, error) {
+	savedSession, timeUntilExpiry, err := c.sessionStore.Load(c.config.Username)
+	if err != nil {
+		fmt.Printf("Warning: Failed to load saved session: %v\n", err)
+		return nil, err
+	}
+
+	if savedSession == nil {
+		return nil, nil
+	}
+
+	// Determine what to do with the saved session
+	switch {
+	case c.config.ForceRefresh:
+		reason := fmt.Sprintf("Forcing session refresh (current session expires in %s)", timeutil.HumanizeDuration(timeUntilExpiry))
+		return c.handleSessionRefresh(savedSession, reason)
+
+	case timeUntilExpiry < time.Duration(constants.SessionRefreshDays)*24*time.Hour && timeUntilExpiry > 0:
+		reason := fmt.Sprintf("Session expires soon (in %s), attempting refresh...", timeutil.HumanizeDuration(timeUntilExpiry))
+		return c.handleSessionRefresh(savedSession, reason)
+
+	case VerifySession(c.httpClient, c.config.APIURL, savedSession):
+		fmt.Printf("Using saved session (expires in %s)\n", timeutil.HumanizeDuration(timeUntilExpiry))
+		return savedSession, nil
+
+	default:
+		fmt.Println("Saved session invalid, re-authenticating...")
+		_ = c.sessionStore.Delete()
+		return nil, nil
+	}
+}
+
+// Authenticate performs the full authentication flow
+func (c *Client) Authenticate() (*api.Session, error) {
+	if err := c.ensureUsername(); err != nil {
+		return nil, err
+	}
+
+	// Try existing session unless clearing or disabled
+	if session := c.handleExistingSession(); session != nil {
+		return session, nil
+	}
+
+	if err := c.ensurePassword(); err != nil {
+		return nil, err
+	}
+
+	// Perform fresh authentication
+	session, err := c.performFreshAuth()
+	if err != nil {
+		return nil, err
+	}
+
+	// Handle session scope upgrade if needed
+	if err := c.upgradeSessionIfNeeded(session); err != nil {
+		return nil, err
+	}
+
+	c.saveSessionIfEnabled(session)
+	return session, nil
+}
+
+// handleExistingSession handles session clearing or reuse
+func (c *Client) handleExistingSession() *api.Session {
+	if c.config.ClearSession {
+		fmt.Println("Clearing saved session...")
+		_ = c.sessionStore.Delete()
+		return nil
+	}
+
+	if c.config.NoSession {
+		return nil
+	}
+
+	session, err := c.tryExistingSession()
+	if err == nil && session != nil {
+		return session
+	}
+	return nil
+}
+
+// performFreshAuth performs SRP authentication and returns a new session
+func (c *Client) performFreshAuth() (*api.Session, error) {
+	authInfo, err := c.getAuthInfo()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get auth info: %w", err)
+	}
+
+	clientProofs, err := c.generateSRPProofs(authInfo)
+	if err != nil {
+		return nil, err
+	}
+
+	authReq := c.buildAuthRequest(authInfo, clientProofs)
+
+	// Handle 2FA if needed
+	if authInfo.TwoFA.Enabled == constants.EnabledTrue && authInfo.TwoFA.TOTP == constants.EnabledTrue {
+		code, err := c.get2FACode()
+		if err != nil {
+			return nil, err
+		}
+		authReq["TwoFactorCode"] = code
+	}
+
+	session, err := c.sendAuthRequest(authReq)
+	if err != nil {
+		return nil, err
+	}
+
+	// Verify server proof
+	if session.ServerProof != base64.StdEncoding.EncodeToString(clientProofs.ExpectedServerProof) {
+		return nil, fmt.Errorf("server proof verification failed")
+	}
+
+	return session, nil
+}
+
+// generateSRPProofs generates SRP client proofs for authentication
+func (c *Client) generateSRPProofs(authInfo *api.AuthInfoResponse) (*srp.Proofs, error) {
+	auth, err := srp.NewAuth(
+		authInfo.Version,
+		c.config.Username,
+		[]byte(c.config.Password),
+		authInfo.Salt,
+		authInfo.Modulus,
+		authInfo.ServerEphemeral,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create SRP auth: %w", err)
+	}
+
+	proofs, err := auth.GenerateProofs(2048)
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate SRP proofs: %w", err)
+	}
+	return proofs, nil
+}
+
+// buildAuthRequest builds the authentication request payload
+func (c *Client) buildAuthRequest(authInfo *api.AuthInfoResponse, proofs *srp.Proofs) map[string]interface{} {
+	return map[string]interface{}{
+		"Username":          c.config.Username,
+		"ClientEphemeral":   base64.StdEncoding.EncodeToString(proofs.ClientEphemeral),
+		"ClientProof":       base64.StdEncoding.EncodeToString(proofs.ClientProof),
+		"SRPSession":        authInfo.SRPSession,
+		"PersistentCookies": 0,
+	}
+}
+
+// upgradeSessionIfNeeded upgrades session with 2FA if VPN scope is missing
+func (c *Client) upgradeSessionIfNeeded(session *api.Session) error {
+	hasVPNScope, hasTwoFactorScope := c.checkSessionScopes(session)
+
+	if hasVPNScope || !hasTwoFactorScope {
+		return nil
+	}
+
+	fmt.Println("Session lacks VPN scope - 2FA verification required to upgrade session...")
+	code, err := c.get2FACode()
+	if err != nil {
+		return fmt.Errorf("failed to get 2FA code: %w", err)
+	}
+
+	updatedScopes, err := c.submit2FA(session, code)
+	if err != nil {
+		return fmt.Errorf("2FA verification failed: %w", err)
+	}
+	session.Scopes = updatedScopes
+	fmt.Println("2FA verified - session upgraded with VPN scope")
+	return nil
+}
+
+// checkSessionScopes checks if session has VPN and twofactor scopes
+func (c *Client) checkSessionScopes(session *api.Session) (hasVPN, hasTwoFactor bool) {
+	for _, scope := range session.Scopes {
+		switch scope {
+		case "vpn":
+			hasVPN = true
+		case "twofactor":
+			hasTwoFactor = true
+		}
+	}
+	return
+}
+
+// saveSessionIfEnabled saves the session if persistence is enabled
+func (c *Client) saveSessionIfEnabled(session *api.Session) {
+	if c.config.NoSession {
+		return
+	}
+
+	sessionDuration, err := timeutil.ParseSessionDuration(c.config.SessionDuration)
+	if err != nil {
+		fmt.Printf("Warning: Invalid session duration, using default: %v\n", err)
+		sessionDuration = 0
+	}
+
+	if err := c.sessionStore.Save(session, c.config.Username, sessionDuration); err != nil {
+		fmt.Printf("Warning: Failed to save session: %v\n", err)
+	}
+}
+
+func (c *Client) ensureUsername() error {
+	if c.config.Username == "" {
+		fmt.Print("Username (without @protonmail.com): ")
+		reader := bufio.NewReader(os.Stdin)
+		username, err := reader.ReadString('\n')
+		if err != nil {
+			return fmt.Errorf("error reading username: %w", err)
+		}
+		c.config.Username = strings.TrimSpace(username)
+		if c.config.Username == "" {
+			return fmt.Errorf("username cannot be empty")
+		}
+	}
+	return nil
+}
+
+func (c *Client) ensurePassword() error {
+	if c.config.Password == "" {
+		fmt.Print("Password: ")
+		passwordBytes, err := term.ReadPassword(int(os.Stdin.Fd()))
+		fmt.Println()
+		if err != nil {
+			return fmt.Errorf("error reading password: %w", err)
+		}
+		c.config.Password = string(passwordBytes)
+	}
+	return nil
+}
+
+func (c *Client) get2FACode() (string, error) {
+	fmt.Print("2FA Code: ")
+	reader := bufio.NewReader(os.Stdin)
+	code, err := reader.ReadString('\n')
+	if err != nil {
+		return "", fmt.Errorf("error reading 2FA code: %w", err)
+	}
+	code = strings.TrimSpace(code)
+
+	// Validate that code is numeric (TOTP codes are 6 digits)
+	if code == "" {
+		return "", fmt.Errorf("2FA code cannot be empty")
+	}
+
+	for _, c := range code {
+		if c < '0' || c > '9' {
+			return "", fmt.Errorf("2FA code must be numeric (TOTP only).\n" +
+				"FIDO2/WebAuthn security keys are not supported.\n" +
+				"Please ensure you have TOTP (authenticator app) configured as your 2FA method")
+		}
+	}
+
+	return code, nil
+}
+
+func (c *Client) getAuthInfo() (*api.AuthInfoResponse, error) {
+	reqBody := map[string]interface{}{
+		"Username": c.config.Username,
+		"Intent":   "Proton",
+	}
+
+	body, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, c.config.APIURL+"/core/v4/auth/info", bytes.NewBuffer(body))
+	if err != nil {
+		return nil, err
+	}
+
+	c.setHeaders(req)
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	respBody, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("HTTP error %d: %s", resp.StatusCode, string(respBody))
+	}
+
+	var authInfo api.AuthInfoResponse
+	if err := json.Unmarshal(respBody, &authInfo); err != nil {
+		return nil, fmt.Errorf("failed to parse auth info: %w", err)
+	}
+
+	if authInfo.Code != CodeSuccess {
+		return nil, fmt.Errorf("failed to get auth info, code: %d", authInfo.Code)
+	}
+
+	// Validate required fields
+	if authInfo.Modulus == "" {
+		return nil, fmt.Errorf("received empty modulus from auth info")
+	}
+	if authInfo.ServerEphemeral == "" {
+		return nil, fmt.Errorf("received empty server ephemeral from auth info")
+	}
+
+	return &authInfo, nil
+}
+
+func (c *Client) sendAuthRequest(authReq map[string]interface{}) (*api.Session, error) {
+	body, err := json.Marshal(authReq)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, c.config.APIURL+"/core/v4/auth", bytes.NewBuffer(body))
+	if err != nil {
+		return nil, err
+	}
+
+	c.setHeaders(req)
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	respBody, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("authentication HTTP error %d: %s", resp.StatusCode, string(respBody))
+	}
+
+	var session api.Session
+	if err := json.Unmarshal(respBody, &session); err != nil {
+		return nil, err
+	}
+
+	// Handle mailbox password request (2-password mode)
+	// Code 10013 means the account uses legacy 2-password mode which requires a separate mailbox password
+	// VPN doesn't need mailbox decryption, but the auth flow requires completing it
+	if session.Code == CodeMailboxPasswordError {
+		return nil, fmt.Errorf("your account uses legacy 2-password mode which is not supported.\n" +
+			"Please switch to single-password mode:\n" +
+			"  1. Go to account.proton.me\n" +
+			"  2. Settings → All settings → Account and password → Passwords\n" +
+			"  3. Switch to 'One-password mode'\n" +
+			"This is recommended by Proton for most users and is required for this tool")
+	}
+
+	if session.Code != CodeSuccess {
+		return nil, NewError(session.Code)
+	}
+
+	return &session, nil
+}
+
+func (c *Client) setHeaders(req *http.Request) {
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("x-pm-appversion", constants.AppVersion)
+	req.Header.Set("User-Agent", constants.UserAgent)
+}
+
+// submit2FA submits a 2FA code to upgrade the session with additional scopes (like VPN)
+func (c *Client) submit2FA(session *api.Session, code string) ([]string, error) {
+	reqBody := map[string]interface{}{
+		"TwoFactorCode": code,
+	}
+
+	body, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, c.config.APIURL+"/core/v4/auth/2fa", bytes.NewBuffer(body))
+	if err != nil {
+		return nil, err
+	}
+
+	// Need to include auth headers for 2FA upgrade
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", session.AccessToken))
+	req.Header.Set("x-pm-uid", session.UID)
+	req.Header.Set("x-pm-appversion", constants.AppVersion)
+	req.Header.Set("User-Agent", constants.UserAgent)
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	respBody, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("2FA HTTP error %d: %s", resp.StatusCode, string(respBody))
+	}
+
+	// Parse response to get updated scopes
+	var twoFAResp struct {
+		Code   int      `json:"Code"`
+		Scopes []string `json:"Scopes"`
+		Error  string   `json:"Error,omitempty"`
+	}
+	if err := json.Unmarshal(respBody, &twoFAResp); err != nil {
+		return nil, fmt.Errorf("failed to parse 2FA response: %w", err)
+	}
+
+	if twoFAResp.Code != CodeSuccess {
+		if twoFAResp.Error != "" {
+			return nil, fmt.Errorf("2FA failed (code %d): %s", twoFAResp.Code, twoFAResp.Error)
+		}
+		return nil, NewError(twoFAResp.Code)
+	}
+
+	return twoFAResp.Scopes, nil
+}

protonvpn-wg-confgen/internal/auth/errors.go

@@ -0,0 +1,82 @@
+package auth
+
+import (
+	"errors"
+	"fmt"
+
+	"protonvpn-wg-confgen/internal/constants"
+)
+
+// Error codes from ProtonVPN API
+// Official source: github.com/ProtonMail/protoncore_android/.../ResponseCodes.kt
+// See API_REFERENCE.md for full documentation.
+const (
+	CodeSuccess              = constants.APICodeSuccess
+	CodeWrongPassword        = 8002  // PASSWORD_WRONG: Incorrect password
+	CodeWrongPasswordFormat  = 8004  // Password format is incorrect (observed)
+	CodeCaptchaRequired      = 9001  // HUMAN_VERIFICATION_REQUIRED: CAPTCHA needed
+	Code2FARequiredForVPN    = 9100  // VPN-specific: certificate endpoint requires 2FA session (not in official docs)
+	CodeAccountDeleted       = 10002 // ACCOUNT_DELETED: Account has been deleted
+	CodeAccountDisabled      = 10003 // ACCOUNT_DISABLED: Account has been disabled
+	CodeMailboxPasswordError = 10013 // Legacy 2-password mode / invalid refresh token (context-dependent)
+)
+
+// Error represents an authentication error with ProtonVPN-specific error code
+type Error struct {
+	Code    int
+	Message string
+}
+
+// Error implements the error interface
+func (e Error) Error() string {
+	return e.Message
+}
+
+// NewError creates a new authentication error from an API response code
+func NewError(code int) error {
+	message := getErrorMessage(code)
+	return Error{
+		Code:    code,
+		Message: message,
+	}
+}
+
+// getErrorMessage returns a human-readable error message for a given error code
+func getErrorMessage(code int) string {
+	switch code {
+	case CodeWrongPassword:
+		return "incorrect username or password"
+	case CodeWrongPasswordFormat:
+		return "password format is incorrect"
+	case CodeCaptchaRequired:
+		return "CAPTCHA verification required"
+	case Code2FARequiredForVPN:
+		return "2FA required for VPN operations - your session was authenticated without 2FA (device trust). Use -clear-session to force re-authentication with 2FA"
+	case CodeAccountDeleted:
+		return "account has been deleted"
+	case CodeAccountDisabled:
+		return "account has been disabled"
+	case CodeMailboxPasswordError:
+		return "account uses legacy 2-password mode - please switch to single-password mode at account.proton.me"
+	default:
+		return fmt.Sprintf("authentication failed with code: %d", code)
+	}
+}
+
+// IsAccountError checks if the error is an account status error (deleted or disabled)
+func IsAccountError(err error) bool {
+	var authErr Error
+	if !errors.As(err, &authErr) {
+		return false
+	}
+	return authErr.Code == CodeAccountDeleted || authErr.Code == CodeAccountDisabled
+}
+
+// IsCaptchaError checks if the error requires CAPTCHA verification
+func IsCaptchaError(err error) bool {
+	var authErr Error
+	if !errors.As(err, &authErr) {
+		return false
+	}
+	return authErr.Code == CodeCaptchaRequired
+}

protonvpn-wg-confgen/internal/auth/session.go

@@ -0,0 +1,210 @@
+package auth
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"time"
+
+	"protonvpn-wg-confgen/internal/api"
+	"protonvpn-wg-confgen/internal/constants"
+)
+
+// SessionStore handles persistent session storage
+type SessionStore struct {
+	filePath string
+}
+
+// NewSessionStore creates a new session store
+func NewSessionStore() *SessionStore {
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		// Fallback to current directory
+		homeDir = "."
+	}
+
+	return &SessionStore{
+		filePath: filepath.Join(homeDir, constants.SessionFileName),
+	}
+}
+
+// SavedSession represents a session with metadata
+type SavedSession struct {
+	Session   *api.Session `json:"session"`
+	Username  string       `json:"username"`
+	SavedAt   time.Time    `json:"saved_at"`
+	ExpiresAt time.Time    `json:"expires_at"`
+}
+
+// Save stores the session to disk
+func (s *SessionStore) Save(session *api.Session, username string, duration time.Duration) error {
+	savedSession := &SavedSession{
+		Session:  session,
+		Username: username,
+		SavedAt:  time.Now(),
+	}
+
+	// Calculate expiration based on API response
+	apiExpiration := time.Now().Add(time.Duration(session.ExpiresIn) * time.Second)
+
+	if duration == 0 {
+		// Use the API's expiration
+		savedSession.ExpiresAt = apiExpiration
+	} else {
+		// Use the user-specified duration, but cap it at API expiration
+		userExpiration := time.Now().Add(duration)
+		if userExpiration.After(apiExpiration) {
+			savedSession.ExpiresAt = apiExpiration
+		} else {
+			savedSession.ExpiresAt = userExpiration
+		}
+	}
+
+	data, err := json.MarshalIndent(savedSession, "", "  ")
+	if err != nil {
+		return fmt.Errorf("failed to marshal session: %w", err)
+	}
+
+	err = os.WriteFile(s.filePath, data, constants.SessionFileMode)
+	if err != nil {
+		return fmt.Errorf("failed to write session file: %w", err)
+	}
+
+	return nil
+}
+
+// Load retrieves a saved session from disk
+func (s *SessionStore) Load(username string) (*api.Session, time.Duration, error) {
+	data, err := os.ReadFile(s.filePath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, 0, nil // No saved session
+		}
+		return nil, 0, fmt.Errorf("failed to read session file: %w", err)
+	}
+
+	var savedSession SavedSession
+	err = json.Unmarshal(data, &savedSession)
+	if err != nil {
+		return nil, 0, fmt.Errorf("failed to unmarshal session: %w", err)
+	}
+
+	// Check if session is for the same user
+	if savedSession.Username != username {
+		return nil, 0, nil
+	}
+
+	// Check if session has expired
+	now := time.Now()
+	if now.After(savedSession.ExpiresAt) {
+		// Delete expired session
+		_ = s.Delete()
+		return nil, 0, nil
+	}
+
+	// Calculate time until expiration
+	timeUntilExpiry := savedSession.ExpiresAt.Sub(now)
+
+	return savedSession.Session, timeUntilExpiry, nil
+}
+
+// Delete removes the saved session
+func (s *SessionStore) Delete() error {
+	err := os.Remove(s.filePath)
+	if err != nil && !os.IsNotExist(err) {
+		return fmt.Errorf("failed to delete session file: %w", err)
+	}
+	return nil
+}
+
+// GetPath returns the session file path
+func (s *SessionStore) GetPath() string {
+	return s.filePath
+}
+
+// RefreshSession attempts to refresh the session using the refresh token.
+// It returns a new session with updated tokens if successful.
+func RefreshSession(httpClient *http.Client, apiURL string, oldSession *api.Session) (*api.Session, error) {
+	// Based on proton-python-client/proton/api.py refresh() method
+	reqBody := map[string]interface{}{
+		"ResponseType": "token",
+		"GrantType":    "refresh_token",
+		"RefreshToken": oldSession.RefreshToken,
+		"RedirectURI":  "http://protonmail.ch",
+	}
+
+	body, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, apiURL+"/auth/refresh", bytes.NewBuffer(body))
+	if err != nil {
+		return nil, err
+	}
+
+	// Set standard headers
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("x-pm-appversion", constants.AppVersion)
+	req.Header.Set("User-Agent", constants.UserAgent)
+
+	// Include auth headers for refresh
+	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", oldSession.AccessToken))
+	req.Header.Set("x-pm-uid", oldSession.UID)
+
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	respBody, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode == http.StatusOK {
+		var session api.Session
+		if err := json.Unmarshal(respBody, &session); err != nil {
+			return nil, err
+		}
+		if constants.IsSuccessCode(session.Code) {
+			return &session, nil
+		}
+	}
+
+	// If refresh fails, return error to trigger re-authentication
+	return nil, fmt.Errorf("refresh failed (status %d): %s", resp.StatusCode, string(respBody))
+}
+
+// VerifySession checks if a session is still valid by making a test API request.
+func VerifySession(httpClient *http.Client, apiURL string, session *api.Session) bool {
+	// Make a simple request to verify the session
+	req, err := http.NewRequest(http.MethodGet, apiURL+"/vpn/v1/logicals", http.NoBody)
+	if err != nil {
+		return false
+	}
+
+	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", session.AccessToken))
+	req.Header.Set("x-pm-uid", session.UID)
+	req.Header.Set("x-pm-appversion", constants.AppVersion)
+	req.Header.Set("User-Agent", constants.UserAgent)
+
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return false
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	// If we get a 401, the session is invalid
+	if resp.StatusCode == http.StatusUnauthorized {
+		return false
+	}
+
+	// Any 2xx response means the session is valid
+	return resp.StatusCode >= 200 && resp.StatusCode < 300
+}

protonvpn-wg-confgen/internal/config/flags.go

@@ -0,0 +1,120 @@
+// Package config handles command-line argument parsing and configuration management.
+package config
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+
+	"protonvpn-wg-confgen/internal/constants"
+	"protonvpn-wg-confgen/pkg/validation"
+)
+
+// Parse parses command-line flags and returns a Config
+func Parse() (*Config, error) {
+	cfg := &Config{}
+
+	var countriesFlag string
+	var dnsServersFlag string
+	var allowedIPsFlag string
+
+	// Set default DNS and allowed IPs based on IPv6 support
+	defaultDNS := constants.DefaultDNSIPv4
+	defaultAllowedIPs := constants.DefaultAllowedIPsIPv4
+
+	// Authentication flags
+	flag.StringVar(&cfg.Username, "username", "", "ProtonVPN username")
+	flag.StringVar(&cfg.Password, "password", "", "ProtonVPN password (will prompt if not provided)")
+
+	// Server selection flags
+	flag.StringVar(&countriesFlag, "countries", "", "Comma-separated list of country codes (e.g., US,NL,CH)")
+	flag.BoolVar(&cfg.P2PServersOnly, "p2p-only", constants.DefaultP2POnly, "Use only P2P-enabled servers")
+	flag.BoolVar(&cfg.SecureCoreOnly, "secure-core", false, "Use only Secure Core servers (multi-hop through privacy-friendly countries)")
+	flag.BoolVar(&cfg.FreeOnly, "free-only", false, "Use only Free tier servers (tier 0)")
+
+	// Output configuration
+	flag.StringVar(&cfg.OutputFile, "output", "protonvpn.conf", "Output WireGuard configuration file")
+	flag.StringVar(&cfg.DeviceName, "device-name", "", "Device name for WireGuard config (auto-generated if empty)")
+
+	// Network configuration
+	flag.BoolVar(&cfg.EnableIPv6, "ipv6", false, "Enable IPv6 support")
+	flag.StringVar(&dnsServersFlag, "dns", "", "Comma-separated list of DNS servers (defaults based on IPv6 setting)")
+	flag.StringVar(&allowedIPsFlag, "allowed-ips", "", "Comma-separated list of allowed IPs (defaults based on IPv6 setting)")
+	flag.BoolVar(&cfg.EnableAccelerator, "accelerator", true, "Enable VPN accelerator")
+
+	// Certificate configuration
+	flag.StringVar(&cfg.Duration, "duration", constants.DefaultCertDuration, "Certificate duration (e.g., 30m, 24h, 7d, 1h30m). Max: 365d")
+
+	// Session management
+	flag.BoolVar(&cfg.ClearSession, "clear-session", false, "Clear saved session and force re-authentication")
+	flag.BoolVar(&cfg.NoSession, "no-session", false, "Don't save or use session persistence")
+	flag.BoolVar(&cfg.ForceRefresh, "force-refresh", false, "Force session refresh even if not expired")
+	flag.StringVar(&cfg.SessionDuration, "session-duration", "0", "Session cache duration (e.g., 12h, 24h, 7d). 0 = no expiration")
+
+	// Advanced configuration
+	flag.StringVar(&cfg.APIURL, "api-url", constants.DefaultAPIURL, "ProtonVPN API URL")
+	flag.BoolVar(&cfg.Debug, "debug", false, "Enable debug output")
+
+	flag.Parse()
+
+	// Validate required flags
+	if countriesFlag == "" {
+		return nil, fmt.Errorf("countries flag is required")
+	}
+
+	// Parse and validate country codes
+	cfg.Countries = parseCountries(countriesFlag)
+	for _, country := range cfg.Countries {
+		if !validation.IsValidCountryCode(country) {
+			return nil, fmt.Errorf("invalid country code: %s", country)
+		}
+	}
+
+	// Set defaults based on IPv6 setting
+	if cfg.EnableIPv6 {
+		defaultDNS = fmt.Sprintf("%s,%s", constants.DefaultDNSIPv4, constants.DefaultDNSIPv6)
+		defaultAllowedIPs = fmt.Sprintf("%s,%s", constants.DefaultAllowedIPsIPv4, constants.DefaultAllowedIPsIPv6)
+	}
+
+	// Use defaults if flags are empty
+	if dnsServersFlag == "" {
+		dnsServersFlag = defaultDNS
+	}
+	if allowedIPsFlag == "" {
+		allowedIPsFlag = defaultAllowedIPs
+	}
+
+	// Parse lists (with space trimming)
+	cfg.DNSServers = parseCommaSeparatedList(dnsServersFlag)
+	cfg.AllowedIPs = parseCommaSeparatedList(allowedIPsFlag)
+
+	// Clean up username
+	cfg.Username = validation.CleanUsername(cfg.Username)
+
+	return cfg, nil
+}
+
+// parseCommaSeparatedList parses a comma-separated string into a trimmed slice
+func parseCommaSeparatedList(input string) []string {
+	parts := strings.Split(input, ",")
+	var result []string
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if part != "" {
+			result = append(result, part)
+		}
+	}
+	return result
+}
+
+// parseCountries parses and normalizes country codes
+func parseCountries(countriesFlag string) []string {
+	return parseCommaSeparatedList(strings.ToUpper(countriesFlag))
+}
+
+// PrintUsage prints usage information
+func PrintUsage() {
+	fmt.Fprintf(os.Stderr, "Usage: %s -username <username> -countries <country-codes> [options]\n\n", os.Args[0])
+	flag.PrintDefaults()
+}

protonvpn-wg-confgen/internal/config/types.go

@@ -0,0 +1,48 @@
+package config
+
+import "fmt"
+
+// Config holds all configuration options
+type Config struct {
+	// Authentication
+	Username string
+	Password string
+
+	// Server selection
+	Countries      []string
+	P2PServersOnly bool
+	SecureCoreOnly bool
+	FreeOnly       bool
+
+	// Output configuration
+	OutputFile       string
+	ClientPrivateKey string
+	DeviceName       string
+
+	// Network configuration
+	DNSServers        []string
+	AllowedIPs        []string
+	EnableAccelerator bool
+	EnableIPv6        bool
+
+	// Certificate configuration
+	Duration string
+
+	// Session management
+	ClearSession    bool
+	NoSession       bool
+	ForceRefresh    bool
+	SessionDuration string
+
+	// Advanced configuration
+	APIURL string
+	Debug  bool
+}
+
+// ValidateCredentials checks if we have the required credentials
+func (c *Config) ValidateCredentials() error {
+	if c.Username == "" {
+		return fmt.Errorf("username is required")
+	}
+	return nil
+}

protonvpn-wg-confgen/internal/constants/api.go

@@ -0,0 +1,37 @@
+// Package constants defines constants used throughout the application.
+package constants
+
+// API endpoints
+const (
+	DefaultAPIURL   = "https://vpn-api.proton.me"
+	AuthInfoPath    = "/core/v4/auth/info"
+	AuthPath        = "/core/v4/auth"
+	RefreshPath     = "/auth/refresh"
+	CertificatePath = "/vpn/v1/certificate"
+	LogicalsPath    = "/vpn/v1/logicals"
+)
+
+// API version headers - can be overridden at build time via ldflags:
+// go build -ldflags "-X .../internal/constants.AppVersion=linux-vpn@X.Y.Z"
+var (
+	AppVersion = "linux-vpn@4.13.1"
+	UserAgent  = "ProtonVPN/4.13.1 (Linux; Ubuntu)"
+)
+
+// API response codes
+// Reference: proton-python-client/proton/api.py checks for codes 1000 and 1001
+const (
+	APICodeSuccess     = 1000
+	APICodeMultiStatus = 1001 // Also indicates success in some contexts
+)
+
+// IsSuccessCode checks if an API response code indicates success
+func IsSuccessCode(code int) bool {
+	return code == APICodeSuccess || code == APICodeMultiStatus
+}
+
+// Server/feature status values
+const (
+	StatusOnline = 1
+	EnabledTrue  = 1
+)

protonvpn-wg-confgen/internal/constants/defaults.go

@@ -0,0 +1,14 @@
+package constants
+
+// Certificate defaults
+const (
+	DefaultCertDuration = "365d"
+	MaxCertDuration     = 365 // days
+	CertMode            = "persistent"
+	PublicKeyMode       = "EC"
+)
+
+// Server selection defaults
+const (
+	DefaultP2POnly = true
+)

protonvpn-wg-confgen/internal/constants/session.go

@@ -0,0 +1,9 @@
+package constants
+
+// Session defaults
+const (
+	SessionFileName      = ".protonvpn-session.json"
+	SessionFileMode      = 0o600   // Read/write for owner only
+	SessionRefreshDays   = 7       // Refresh when less than 7 days remain
+	SessionExpirySeconds = 2592000 // 30 days in seconds (from API)
+)

protonvpn-wg-confgen/internal/constants/wireguard.go

@@ -0,0 +1,17 @@
+package constants
+
+// WireGuard defaults
+const (
+	WireGuardPort = 51820
+	DefaultMTU    = 1420
+
+	// IPv4 configuration
+	WireGuardIPv4         = "10.2.0.2/32"
+	DefaultDNSIPv4        = "10.2.0.1"
+	DefaultAllowedIPsIPv4 = "0.0.0.0/0"
+
+	// IPv6 configuration
+	WireGuardIPv6         = "2a07:b944::2:2/128"
+	DefaultDNSIPv6        = "2a07:b944::2:1"
+	DefaultAllowedIPsIPv6 = "::/0"
+)

protonvpn-wg-confgen/internal/vpn/client.go

@@ -0,0 +1,148 @@
+// Package vpn manages VPN certificate generation and server interactions.
+package vpn
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	"protonvpn-wg-confgen/internal/api"
+	"protonvpn-wg-confgen/internal/config"
+	"protonvpn-wg-confgen/internal/constants"
+	"protonvpn-wg-confgen/pkg/timeutil"
+
+	"github.com/ProtonVPN/go-vpn-lib/ed25519"
+)
+
+// Client handles VPN operations
+type Client struct {
+	config     *config.Config
+	session    *api.Session
+	httpClient *http.Client
+}
+
+// NewClient creates a new VPN client
+func NewClient(cfg *config.Config, session *api.Session) *Client {
+	return &Client{
+		config:     cfg,
+		session:    session,
+		httpClient: &http.Client{Timeout: 10 * time.Second},
+	}
+}
+
+// GetCertificate generates a VPN certificate
+func (c *Client) GetCertificate(keyPair *ed25519.KeyPair) (*api.VPNInfo, error) {
+	publicKeyPEM, err := keyPair.PublicKeyPKIXPem()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get public key PEM: %w", err)
+	}
+
+	// Use provided device name or generate one
+	deviceName := c.config.DeviceName
+	if deviceName == "" {
+		deviceName = fmt.Sprintf("WireGuard-%s-%d", c.config.Username, time.Now().Unix())
+	}
+
+	// Parse duration
+	durationStr, err := timeutil.ParseToMinutes(c.config.Duration)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse duration: %w", err)
+	}
+
+	// Build certificate request matching official ProtonVPN API format
+	// Feature keys from: python-proton-vpn-api-core/proton/vpn/session/fetcher.py
+	certReq := map[string]interface{}{
+		"ClientPublicKey":     publicKeyPEM,
+		"ClientPublicKeyMode": "EC",
+		"Mode":                "persistent", // Create persistent configuration
+		"DeviceName":          deviceName,
+		"Duration":            durationStr,
+		"Features": map[string]interface{}{
+			"NetShieldLevel": 0,                          // NetShield disabled
+			"RandomNAT":      false,                      // Moderate NAT disabled
+			"PortForwarding": false,                      // Port forwarding disabled
+			"SplitTCP":       c.config.EnableAccelerator, // VPN Accelerator (called SplitTCP in API)
+		},
+	}
+
+	certJSON, err := json.Marshal(certReq)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, c.config.APIURL+"/vpn/v1/certificate", bytes.NewBuffer(certJSON))
+	if err != nil {
+		return nil, err
+	}
+
+	c.setHeaders(req)
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	var vpnInfo api.VPNInfo
+	if err := json.Unmarshal(body, &vpnInfo); err != nil {
+		return nil, err
+	}
+
+	if !constants.IsSuccessCode(vpnInfo.Code) {
+		// Include the actual API error message if available
+		if vpnInfo.Error != "" {
+			return nil, fmt.Errorf("VPN certificate error (code %d): %s", vpnInfo.Code, vpnInfo.Error)
+		}
+		return nil, fmt.Errorf("failed to get VPN certificate, code: %d", vpnInfo.Code)
+	}
+
+	return &vpnInfo, nil
+}
+
+// GetServers fetches the list of VPN servers
+func (c *Client) GetServers() ([]api.LogicalServer, error) {
+	req, err := http.NewRequest(http.MethodGet, c.config.APIURL+"/vpn/v1/logicals", http.NoBody)
+	if err != nil {
+		return nil, err
+	}
+
+	c.setHeaders(req)
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	var response api.LogicalsResponse
+	if err := json.Unmarshal(body, &response); err != nil {
+		return nil, err
+	}
+
+	if !constants.IsSuccessCode(response.Code) {
+		return nil, fmt.Errorf("API returned error code: %d", response.Code)
+	}
+
+	return response.LogicalServers, nil
+}
+
+func (c *Client) setHeaders(req *http.Request) {
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", c.session.AccessToken))
+	req.Header.Set("x-pm-uid", c.session.UID)
+	req.Header.Set("x-pm-appversion", constants.AppVersion)
+	req.Header.Set("User-Agent", constants.UserAgent)
+}

protonvpn-wg-confgen/internal/vpn/servers.go

@@ -0,0 +1,165 @@
+package vpn
+
+import (
+	"errors"
+	"fmt"
+	"sort"
+	"strings"
+
+	"protonvpn-wg-confgen/internal/api"
+	"protonvpn-wg-confgen/internal/config"
+	"protonvpn-wg-confgen/internal/constants"
+)
+
+// ServerSelector handles server selection logic
+type ServerSelector struct {
+	config *config.Config
+}
+
+// NewServerSelector creates a new server selector
+func NewServerSelector(cfg *config.Config) *ServerSelector {
+	return &ServerSelector{config: cfg}
+}
+
+// SelectBest selects the best server based on configuration
+func (s *ServerSelector) SelectBest(servers []api.LogicalServer) (*api.LogicalServer, error) {
+	filtered := s.filterServers(servers)
+
+	if s.config.Debug {
+		s.printDebugServerList(filtered)
+	}
+
+	if len(filtered) == 0 {
+		return nil, s.buildNoServersError()
+	}
+
+	// Sort servers: first by score (descending), then by load (ascending)
+	sort.Slice(filtered, func(i, j int) bool {
+		// If scores are different, higher score wins
+		if filtered[i].Score != filtered[j].Score {
+			return filtered[i].Score > filtered[j].Score
+		}
+		// If scores are equal, lower load wins
+		return filtered[i].Load < filtered[j].Load
+	})
+
+	return &filtered[0], nil
+}
+
+func (s *ServerSelector) filterServers(servers []api.LogicalServer) []api.LogicalServer {
+	var filtered []api.LogicalServer
+
+	for i := range servers {
+		if s.isServerEligible(&servers[i]) {
+			filtered = append(filtered, servers[i])
+		}
+	}
+
+	return filtered
+}
+
+func (s *ServerSelector) isServerEligible(server *api.LogicalServer) bool {
+	// Skip offline servers
+	if server.Status != constants.StatusOnline {
+		return false
+	}
+
+	// Filter by tier based on -free-only flag
+	if s.config.FreeOnly {
+		// When free-only is enabled, only accept Free tier servers
+		if server.Tier != api.TierFree {
+			return false
+		}
+	} else {
+		// Otherwise, filter out free tier servers
+		if server.Tier == api.TierFree {
+			return false
+		}
+	}
+
+	// Filter by P2P support if requested (but not when using Secure Core or Free tier)
+	if s.config.P2PServersOnly && !s.config.SecureCoreOnly && !s.config.FreeOnly && server.Features&api.FeatureP2P == 0 {
+		return false
+	}
+
+	// Filter by Secure Core if requested
+	if s.config.SecureCoreOnly && server.Features&api.FeatureSecureCore == 0 {
+		return false
+	}
+
+	// Filter by country
+	if !s.isCountryMatch(server) {
+		return false
+	}
+
+	// Skip servers with no physical servers
+	if len(server.Servers) == 0 {
+		return false
+	}
+
+	return true
+}
+
+func (s *ServerSelector) isCountryMatch(server *api.LogicalServer) bool {
+	for _, country := range s.config.Countries {
+		if server.ExitCountry == country {
+			return true
+		}
+	}
+	return false
+}
+
+func (s *ServerSelector) buildNoServersError() error {
+	errMsg := fmt.Sprintf("No suitable servers found for countries: %v", s.config.Countries)
+
+	if s.config.SecureCoreOnly {
+		errMsg += " with Secure Core"
+	} else if s.config.P2PServersOnly {
+		errMsg += " with P2P support"
+	}
+
+	return errors.New(errMsg)
+}
+
+// GetBestPhysicalServer returns the best physical server from a logical server
+func GetBestPhysicalServer(server *api.LogicalServer) *api.PhysicalServer {
+	if len(server.Servers) == 0 {
+		return nil
+	}
+
+	// Find the first online physical server
+	for i := range server.Servers {
+		if server.Servers[i].Status == constants.StatusOnline {
+			return &server.Servers[i]
+		}
+	}
+
+	// If no online servers, return the first one
+	return &server.Servers[0]
+}
+
+// printDebugServerList prints a debug list of filtered servers
+func (s *ServerSelector) printDebugServerList(servers []api.LogicalServer) {
+	fmt.Printf("\nDEBUG: Found %d servers after filtering:\n", len(servers))
+	fmt.Println("==================================================================================")
+	fmt.Printf("%-15s | %-18s | %-12s | Load | Score | Features\n", "Server", "City", "Tier")
+	fmt.Println("----------------------------------------------------------------------------------")
+
+	for i := range servers {
+		features := api.GetFeatureNames(servers[i].Features)
+		featureStr := "-"
+		if len(features) > 0 {
+			featureStr = strings.Join(features, ", ")
+		}
+
+		fmt.Printf("%-15s | %-18s | %-12s | %3d%% | %.2f | %s\n",
+			servers[i].Name,
+			servers[i].City,
+			api.GetTierName(servers[i].Tier),
+			servers[i].Load,
+			servers[i].Score,
+			featureStr)
+	}
+
+	fmt.Println("==================================================================================")
+}

protonvpn-wg-confgen/pkg/timeutil/duration.go

@@ -0,0 +1,148 @@
+// Package timeutil provides time-related utility functions.
+package timeutil
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+// pluralize returns singular or plural form based on count
+func pluralize(count int, singular, plural string) string {
+	if count == 1 {
+		return fmt.Sprintf("1 %s", singular)
+	}
+	return fmt.Sprintf("%d %s", count, plural)
+}
+
+// formatTimeComponents formats non-zero time components into a string
+func formatTimeComponents(parts []string) string {
+	return strings.Join(parts, " ")
+}
+
+// formatWeeksAndDays formats weeks and remaining days
+func formatWeeksAndDays(days int) []string {
+	var parts []string
+	weeks := days / 7
+	remainingDays := days % 7
+
+	if weeks > 0 {
+		parts = append(parts, pluralize(weeks, "week", "weeks"))
+	}
+	if remainingDays > 0 {
+		parts = append(parts, pluralize(remainingDays, "day", "days"))
+	}
+	return parts
+}
+
+// formatHoursMinutes formats hours and minutes
+func formatHoursMinutes(hours, minutes int) string {
+	switch {
+	case hours > 0 && minutes > 0:
+		return fmt.Sprintf("%d hours %d minutes", hours, minutes)
+	case hours > 0:
+		return fmt.Sprintf("%d hours", hours)
+	default:
+		return fmt.Sprintf("%d minutes", minutes)
+	}
+}
+
+// formatDaysHoursMinutes formats days, hours, and minutes into a string
+func formatDaysHoursMinutes(days, hours, minutes int) string {
+	// Simple days format (less than a week)
+	if days < 7 {
+		return formatSimpleDays(days, hours, minutes)
+	}
+
+	// Weeks format
+	parts := formatWeeksAndDays(days)
+	if hours > 0 || minutes > 0 {
+		parts = append(parts, formatHoursMinutes(hours, minutes))
+	}
+	return formatTimeComponents(parts)
+}
+
+// formatSimpleDays formats days less than a week with hours and minutes
+func formatSimpleDays(days, hours, minutes int) string {
+	if hours == 0 && minutes == 0 {
+		return pluralize(days, "day", "days")
+	}
+	if minutes == 0 {
+		return fmt.Sprintf("%d days %d hours", days, hours)
+	}
+	return fmt.Sprintf("%d days %d hours %d minutes", days, hours, minutes)
+}
+
+// HumanizeDuration converts a duration to a human-readable format with high precision.
+// It shows progressively less detail for longer durations:
+// - Less than a minute: "less than a minute"
+// - Less than an hour: "X minutes"
+// - Less than a day: "X hours Y minutes"
+// - Less than a week: "X days Y hours Z minutes"
+// - Less than a month: "X weeks Y days Z hours W minutes"
+// - Longer periods: months and years with appropriate detail
+func HumanizeDuration(d time.Duration) string {
+	if d < 0 {
+		return "expired"
+	}
+
+	if d < time.Minute {
+		return "less than a minute"
+	}
+
+	if d < time.Hour {
+		return pluralize(int(d.Minutes()), "minute", "minutes")
+	}
+
+	if d < 24*time.Hour {
+		return formatHoursDuration(d)
+	}
+
+	days := int(d.Hours() / 24)
+	hours := int(d.Hours()) % 24
+	minutes := int(d.Minutes()) % 60
+
+	if days < 30 {
+		return formatDaysHoursMinutes(days, hours, minutes)
+	}
+
+	if days < 365 {
+		return formatMonthsDuration(days)
+	}
+
+	return formatYearsDuration(days)
+}
+
+// formatHoursDuration formats durations less than a day
+func formatHoursDuration(d time.Duration) string {
+	hours := int(d.Hours())
+	minutes := int(d.Minutes()) % 60
+	if minutes == 0 {
+		return pluralize(hours, "hour", "hours")
+	}
+	return fmt.Sprintf("%d hours %d minutes", hours, minutes)
+}
+
+// formatMonthsDuration formats durations between 30 and 365 days
+func formatMonthsDuration(days int) string {
+	months := days / 30
+	remainingDays := days % 30
+	if remainingDays == 0 {
+		return pluralize(months, "month", "months")
+	}
+	return fmt.Sprintf("%d months %d days", months, remainingDays)
+}
+
+// formatYearsDuration formats durations of 365 days or more
+func formatYearsDuration(days int) string {
+	years := days / 365
+	remainingDays := days % 365
+	if remainingDays == 0 {
+		return pluralize(years, "year", "years")
+	}
+	if remainingDays < 30 {
+		return fmt.Sprintf("%d years %d days", years, remainingDays)
+	}
+	months := remainingDays / 30
+	return fmt.Sprintf("%d years %d months", years, months)
+}

protonvpn-wg-confgen/pkg/timeutil/parser.go

@@ -0,0 +1,81 @@
+package timeutil
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// parseDaysDuration handles duration strings like "7d", "30d", "365d"
+func parseDaysDuration(durationStr string) (time.Duration, error) {
+	if !strings.HasSuffix(durationStr, "d") {
+		return 0, fmt.Errorf("not a day duration format")
+	}
+
+	daysStr := strings.TrimSuffix(durationStr, "d")
+	days, err := strconv.Atoi(daysStr)
+	if err != nil {
+		return 0, fmt.Errorf("invalid day value: %s", daysStr)
+	}
+
+	return time.Duration(days) * 24 * time.Hour, nil
+}
+
+// ParseDuration parses a duration string that can be either Go duration or "Xd" format
+func ParseDuration(durationStr string) (time.Duration, error) {
+	// Try days format first
+	if duration, err := parseDaysDuration(durationStr); err == nil {
+		return duration, nil
+	}
+
+	// Fall back to standard Go duration
+	return time.ParseDuration(durationStr)
+}
+
+// ParseToMinutes parses a duration string and converts it to minutes for the ProtonVPN API.
+// Accepts formats like "7d", "30d", "365d", "30m", "24h", "1h30m".
+// Returns the duration in "XXX min" format as expected by the API.
+func ParseToMinutes(durationStr string) (string, error) {
+	duration, err := ParseDuration(durationStr)
+	if err != nil {
+		return "", fmt.Errorf("invalid duration format: %s", durationStr)
+	}
+
+	// Convert to minutes
+	minutes := int(duration.Minutes())
+	if minutes < 1 {
+		return "", fmt.Errorf("duration must be at least 1 minute")
+	}
+
+	// Max 365 days = 525600 minutes
+	maxMinutes := 365 * 24 * 60
+	if minutes > maxMinutes {
+		return "", fmt.Errorf("duration cannot exceed 365 days")
+	}
+
+	return fmt.Sprintf("%d min", minutes), nil
+}
+
+// ParseSessionDuration parses a session duration string for local caching.
+// Accepts formats like "7d", "30d", or standard Go duration strings.
+// Returns 0 to indicate "use API default".
+func ParseSessionDuration(durationStr string) (time.Duration, error) {
+	// Handle "0" as use API default
+	if durationStr == "0" {
+		return 0, nil
+	}
+
+	duration, err := ParseDuration(durationStr)
+	if err != nil {
+		return 0, fmt.Errorf("invalid session duration format: %s", durationStr)
+	}
+
+	// Validate max duration (30 days)
+	maxDuration := 30 * 24 * time.Hour
+	if duration > maxDuration {
+		return 0, fmt.Errorf("session duration cannot exceed 30 days (got: %s)", duration)
+	}
+
+	return duration, nil
+}

protonvpn-wg-confgen/pkg/validation/username.go

@@ -0,0 +1,31 @@
+// Package validation provides input validation utilities.
+package validation
+
+import (
+	"strings"
+)
+
+// CleanUsername removes email domain suffixes from username.
+// ProtonVPN usernames don't include the email domain.
+func CleanUsername(username string) string {
+	username = strings.TrimSpace(username)
+	username = strings.TrimSuffix(username, "@protonmail.com")
+	username = strings.TrimSuffix(username, "@proton.me")
+	username = strings.TrimSuffix(username, "@pm.me")
+	return username
+}
+
+// IsValidCountryCode checks if a country code is valid (2 letters).
+func IsValidCountryCode(code string) bool {
+	return len(code) == 2 && isAlpha(code)
+}
+
+// isAlpha checks if a string contains only alphabetic characters.
+func isAlpha(s string) bool {
+	for _, r := range s {
+		if (r < 'A' || r > 'Z') && (r < 'a' || r > 'z') {
+			return false
+		}
+	}
+	return true
+}

protonvpn-wg-confgen/pkg/wireguard/config.go

@@ -0,0 +1,140 @@
+// Package wireguard generates WireGuard configuration files.
+package wireguard
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"strings"
+	"text/template"
+	"time"
+
+	"protonvpn-wg-confgen/internal/api"
+	"protonvpn-wg-confgen/internal/config"
+	"protonvpn-wg-confgen/internal/constants"
+)
+
+// wireguardConfigTemplate is the template for generating WireGuard configuration
+const wireguardConfigTemplate = `[Interface]
+PrivateKey = {{.PrivateKey}}
+{{.AddressLine}}
+DNS = {{.DNS}}
+
+[Peer]
+PublicKey = {{.PublicKey}}
+AllowedIPs = {{.AllowedIPs}}
+Endpoint = {{.Endpoint}}:{{.Port}}
+`
+
+// configData holds the data for the WireGuard config template
+type configData struct {
+	PrivateKey  string
+	AddressLine string
+	DNS         string
+	PublicKey   string
+	AllowedIPs  string
+	Endpoint    string
+	Port        int
+}
+
+// ConfigGenerator generates WireGuard configuration files
+type ConfigGenerator struct {
+	config   *config.Config
+	template *template.Template
+}
+
+// NewConfigGenerator creates a new configuration generator
+func NewConfigGenerator(cfg *config.Config) *ConfigGenerator {
+	tmpl := template.Must(template.New("wireguard").Parse(wireguardConfigTemplate))
+	return &ConfigGenerator{
+		config:   cfg,
+		template: tmpl,
+	}
+}
+
+// Generate creates a WireGuard configuration file
+func (g *ConfigGenerator) Generate(server *api.LogicalServer, physicalServer *api.PhysicalServer, privateKey string) error {
+	content, err := g.buildConfig(server, physicalServer, privateKey)
+	if err != nil {
+		return err
+	}
+
+	if err := os.WriteFile(g.config.OutputFile, []byte(content), 0o600); err != nil {
+		return fmt.Errorf("failed to write config file: %w", err)
+	}
+
+	return nil
+}
+
+func (g *ConfigGenerator) buildConfig(server *api.LogicalServer, physicalServer *api.PhysicalServer, privateKey string) (string, error) {
+	// Build metadata header
+	metadata := g.buildMetadata(server, physicalServer)
+
+	data := configData{
+		PrivateKey:  privateKey,
+		AddressLine: g.buildAddressLine(),
+		DNS:         strings.Join(g.config.DNSServers, ", "),
+		PublicKey:   physicalServer.X25519PublicKey,
+		AllowedIPs:  strings.Join(g.config.AllowedIPs, ", "),
+		Endpoint:    physicalServer.EntryIP,
+		Port:        constants.WireGuardPort,
+	}
+
+	var buf bytes.Buffer
+	if err := g.template.Execute(&buf, data); err != nil {
+		return "", fmt.Errorf("failed to execute template: %w", err)
+	}
+
+	return metadata + buf.String(), nil
+}
+
+func (g *ConfigGenerator) buildAddressLine() string {
+	if g.config.EnableIPv6 {
+		return fmt.Sprintf("Address = %s, %s", constants.WireGuardIPv4, constants.WireGuardIPv6)
+	}
+	return fmt.Sprintf("Address = %s", constants.WireGuardIPv4)
+}
+
+func (g *ConfigGenerator) buildMetadata(server *api.LogicalServer, physicalServer *api.PhysicalServer) string {
+	var metadata strings.Builder
+
+	metadata.WriteString("# ProtonVPN WireGuard Configuration\n")
+	metadata.WriteString(fmt.Sprintf("# Generated: %s\n", time.Now().Format("2006-01-02 15:04:05 MST")))
+	if g.config.DeviceName != "" {
+		metadata.WriteString(fmt.Sprintf("# Device: %s\n", g.config.DeviceName))
+	}
+	metadata.WriteString("#\n")
+	metadata.WriteString("# Server Information:\n")
+	metadata.WriteString(fmt.Sprintf("# - Name: %s\n", server.Name))
+	metadata.WriteString(fmt.Sprintf("# - Country: %s\n", server.ExitCountry))
+	metadata.WriteString(fmt.Sprintf("# - City: %s\n", server.City))
+	metadata.WriteString(fmt.Sprintf("# - Tier: %s\n", api.GetTierName(server.Tier)))
+	metadata.WriteString(fmt.Sprintf("# - Load: %d%%\n", server.Load))
+	metadata.WriteString(fmt.Sprintf("# - Score: %.2f\n", server.Score))
+
+	// Add features if any
+	features := api.GetFeatureNames(server.Features)
+	if len(features) > 0 {
+		metadata.WriteString(fmt.Sprintf("# - Features: %s\n", strings.Join(features, ", ")))
+	}
+
+	// Add physical server info
+	metadata.WriteString("#\n")
+	metadata.WriteString("# Physical Server:\n")
+	metadata.WriteString(fmt.Sprintf("# - ID: %s\n", physicalServer.ID))
+	metadata.WriteString(fmt.Sprintf("# - Entry IP: %s\n", physicalServer.EntryIP))
+	if physicalServer.ExitIP != physicalServer.EntryIP {
+		metadata.WriteString(fmt.Sprintf("# - Exit IP: %s\n", physicalServer.ExitIP))
+	}
+
+	// Add secure core routing info if applicable
+	if server.EntryCountry != server.ExitCountry && server.EntryCountry != "" {
+		metadata.WriteString("#\n")
+		metadata.WriteString(fmt.Sprintf("# Secure Core Routing: %s → %s\n",
+			server.EntryCountry, server.ExitCountry))
+	}
+
+	metadata.WriteString("#\n\n")
+
+	return metadata.String()
+}

protonvpn-wg-confgen/pkg/wireguard/config_test.go

@@ -0,0 +1,119 @@
+package wireguard
+
+import (
+	"strings"
+	"testing"
+
+	"protonvpn-wg-confgen/internal/api"
+	"protonvpn-wg-confgen/internal/config"
+)
+
+func TestConfigGeneration(t *testing.T) {
+	cfg := &config.Config{
+		DNSServers: []string{"10.2.0.1"},
+		AllowedIPs: []string{"0.0.0.0/0"},
+		OutputFile: "test.conf",
+	}
+
+	generator := NewConfigGenerator(cfg)
+
+	server := &api.LogicalServer{
+		Name: "Test-Server",
+	}
+
+	physicalServer := &api.PhysicalServer{
+		EntryIP:         "192.168.1.1",
+		X25519PublicKey: "testPublicKey123=",
+	}
+
+	privateKey := "testPrivateKey456="
+
+	result, err := generator.buildConfig(server, physicalServer, privateKey)
+	if err != nil {
+		t.Fatalf("buildConfig failed: %v", err)
+	}
+
+	// Check that config starts with comment header
+	if !strings.HasPrefix(result, "# ProtonVPN WireGuard Configuration") {
+		t.Errorf("Expected config to start with header comment, got:\n%s", result[:100])
+	}
+
+	// Check that metadata is present
+	if !strings.Contains(result, "# - Name: Test-Server") {
+		t.Errorf("Expected server name in metadata")
+	}
+
+	// Check for proper WireGuard sections
+	if !strings.Contains(result, "[Interface]") {
+		t.Error("Expected [Interface] section")
+	}
+
+	if !strings.Contains(result, "[Peer]") {
+		t.Error("Expected [Peer] section")
+	}
+
+	// Verify key content
+	expectedContent := []string{
+		"PrivateKey = testPrivateKey456=",
+		"Address = 10.2.0.2/32",
+		"DNS = 10.2.0.1",
+		"PublicKey = testPublicKey123=",
+		"AllowedIPs = 0.0.0.0/0",
+		"Endpoint = 192.168.1.1:51820",
+	}
+
+	for _, expected := range expectedContent {
+		if !strings.Contains(result, expected) {
+			t.Errorf("Expected config to contain '%s'\nGot:\n%s", expected, result)
+		}
+	}
+
+	// Check section order: [Interface] should come before [Peer]
+	interfaceIdx := strings.Index(result, "[Interface]")
+	peerIdx := strings.Index(result, "[Peer]")
+	if interfaceIdx >= peerIdx {
+		t.Error("[Interface] section should come before [Peer] section")
+	}
+}
+
+func TestConfigGenerationWithIPv6(t *testing.T) {
+	cfg := &config.Config{
+		DNSServers: []string{"10.2.0.1", "2a07:b944::2:1"},
+		AllowedIPs: []string{"0.0.0.0/0", "::/0"},
+		OutputFile: "test.conf",
+		EnableIPv6: true,
+	}
+
+	generator := NewConfigGenerator(cfg)
+
+	server := &api.LogicalServer{
+		Name: "Test-Server",
+	}
+
+	physicalServer := &api.PhysicalServer{
+		EntryIP:         "192.168.1.1",
+		X25519PublicKey: "testPublicKey123=",
+	}
+
+	privateKey := "testPrivateKey456="
+
+	result, err := generator.buildConfig(server, physicalServer, privateKey)
+	if err != nil {
+		t.Fatalf("buildConfig failed: %v", err)
+	}
+
+	// Check that IPv6 address is included
+	if !strings.Contains(result, "Address = 10.2.0.2/32, 2a07:b944::2:2/128") {
+		t.Errorf("Expected IPv6 address in config, got:\n%s", result)
+	}
+
+	// Check DNS servers
+	if !strings.Contains(result, "DNS = 10.2.0.1, 2a07:b944::2:1") {
+		t.Errorf("Expected both DNS servers in config, got:\n%s", result)
+	}
+
+	// Check AllowedIPs
+	if !strings.Contains(result, "AllowedIPs = 0.0.0.0/0, ::/0") {
+		t.Errorf("Expected both IPv4 and IPv6 in AllowedIPs, got:\n%s", result)
+	}
+}