i18n

src/client/App.js

@@ -4,6 +4,8 @@ import Dashboard from './Dashboard';
 import RuleManager from './RuleManager';
 import LoginDialog from './LoginDialog';
 import { AuthProvider, useAuth } from './AuthContext';
+import { I18nProvider, useI18n } from './I18nContext';
+import LanguageSwitcher from './LanguageSwitcher';
 
 // Gruvbox Dark color palette
 const gruvboxDark = {
@@ -44,6 +46,7 @@ const darkTheme = createTheme({
 
 function AppContent() {
     const { user, loading, login, logout, isAuthenticated, isAdmin } = useAuth();
+    const { t } = useI18n();
     const [showLogin, setShowLogin] = useState(false);
 
     return (
@@ -51,9 +54,10 @@ function AppContent() {
             <AppBar position="static">
                 <Toolbar>
                     <Typography variant="h6" component="div" sx={{ flexGrow: 1 }}>
-                        Tischlerei Dashboard
+                        {t('app.title')}
                     </Typography>
                     <Box sx={{ display: 'flex', alignItems: 'center', gap: 2 }}>
+                        <LanguageSwitcher />
                         {isAuthenticated ? (
                             <>
                                 <Chip
@@ -69,7 +73,7 @@ function AppContent() {
                                 />
                                 {isAdmin && (
                                     <Chip
-                                        label="ADMIN"
+                                        label={t('app.admin')}
                                         size="small"
                                         sx={{
                                             bgcolor: gruvboxDark.purple,
@@ -83,7 +87,7 @@ function AppContent() {
                                     onClick={logout}
                                     size="small"
                                 >
-                                    Logout
+                                    {t('app.logout')}
                                 </Button>
                             </>
                         ) : (
@@ -94,7 +98,7 @@ function AppContent() {
                                 size="small"
                                 sx={{ borderColor: gruvboxDark.aqua }}
                             >
-                                🔐 Admin Login
+                                {t('app.adminLogin')}
                             </Button>
                         )}
                     </Box>
@@ -121,9 +125,11 @@ function App() {
     return (
         <ThemeProvider theme={darkTheme}>
             <CssBaseline />
-            <AuthProvider>
+            <I18nProvider>
-                <AppContent />
+                <AuthProvider>
-            </AuthProvider>
+                    <AppContent />
+                </AuthProvider>
+            </I18nProvider>
         </ThemeProvider>
     );
 }

src/client/ControllerCard.js

@@ -2,8 +2,10 @@ import React, { useState, useEffect } from 'react';
 import { Card, CardHeader, CardContent, Divider, Grid, Box, Typography } from '@mui/material';
 import EnvChart from './EnvChart';
 import LevelChart from './LevelChart';
+import { useI18n } from './I18nContext';
 
 export default function ControllerCard({ controllerName, ports, range }) {
+    const { t } = useI18n();
     const [envData, setEnvData] = useState([]);
     const [portData, setPortData] = useState({});
 
@@ -56,7 +58,7 @@ export default function ControllerCard({ controllerName, ports, range }) {
                 {/* Environment Chart */}
                 <Box sx={{ height: 350, mb: 6 }}>
                     <Typography variant="h6" color="text.secondary" gutterBottom>
-                        Environment (Temp / Humidity)
+                        {t('controller.environment')}
                     </Typography>
                     <EnvChart data={envData} range={range} />
                 </Box>
@@ -75,7 +77,7 @@ export default function ControllerCard({ controllerName, ports, range }) {
                                 <Card variant="outlined" sx={{ bgcolor: 'background.paper' }}>
                                     <CardContent>
                                         <Typography variant="h6" gutterBottom>
-                                            {port.port_name || `Port ${port.port}`}
+                                            {port.port_name || `${t('controller.port')} ${port.port}`}
                                         </Typography>
                                         <Box sx={{ height: 250 }}>
                                             <LevelChart data={pData} isLight={isLight} isCO2={isCO2} range={range} />

src/client/Dashboard.js

@@ -1,8 +1,10 @@
 import React, { useState, useEffect, useCallback } from 'react';
 import { Grid, Typography, Button, ButtonGroup, Box, Alert } from '@mui/material';
 import ControllerCard from './ControllerCard';
+import { useI18n } from './I18nContext';
 
 export default function Dashboard() {
+    const { t } = useI18n();
     const [groupedDevices, setGroupedDevices] = useState({});
     const [loading, setLoading] = useState(true);
     const [error, setError] = useState(null);
@@ -44,7 +46,7 @@ export default function Dashboard() {
     // Auto-refresh logic (basic rerender trigger could be added here, 
     // but simpler to let ControllerCard handle data fetching internally based on props)
 
-    if (loading) return <Typography>Loading devices...</Typography>;
+    if (loading) return <Typography>{t('dashboard.loading')}</Typography>;
     if (error) return <Alert severity="error">{error}</Alert>;
 
     return (
@@ -55,19 +57,19 @@ export default function Dashboard() {
                         onClick={() => setRange('day')}
                         color={range === 'day' ? 'primary' : 'inherit'}
                     >
-                        24 Hours
+                        {t('dashboard.hours24')}
                     </Button>
                     <Button
                         onClick={() => setRange('week')}
                         color={range === 'week' ? 'primary' : 'inherit'}
                     >
-                        7 Days
+                        {t('dashboard.days7')}
                     </Button>
                     <Button
                         onClick={() => setRange('month')}
                         color={range === 'month' ? 'primary' : 'inherit'}
                     >
-                        30 Days
+                        {t('dashboard.days30')}
                     </Button>
                 </ButtonGroup>
             </Box>

src/client/I18nContext.js

@@ -0,0 +1,82 @@
+import React, { createContext, useContext, useState, useCallback, useMemo } from 'react';
+import en from './i18n/en.json';
+import de from './i18n/de.json';
+
+const translations = { en, de };
+
+// Cookie helpers
+function getCookie(name) {
+    const match = document.cookie.match(new RegExp('(^| )' + name + '=([^;]+)'));
+    return match ? match[2] : null;
+}
+
+function setCookie(name, value, days = 365) {
+    const expires = new Date(Date.now() + days * 864e5).toUTCString();
+    document.cookie = `${name}=${value}; expires=${expires}; path=/; SameSite=Lax`;
+}
+
+// Get initial language from cookie or browser preference
+function getInitialLanguage() {
+    const cookieLang = getCookie('lang');
+    if (cookieLang && translations[cookieLang]) {
+        return cookieLang;
+    }
+    // Check browser preference
+    const browserLang = navigator.language?.slice(0, 2);
+    if (browserLang === 'de') return 'de';
+    return 'en';
+}
+
+const I18nContext = createContext(null);
+
+export function I18nProvider({ children }) {
+    const [language, setLanguageState] = useState(getInitialLanguage);
+
+    const setLanguage = useCallback((lang) => {
+        if (translations[lang]) {
+            setLanguageState(lang);
+            setCookie('lang', lang);
+        }
+    }, []);
+
+    // Translation function with nested key support (e.g., 'app.title')
+    const t = useCallback((key, params = {}) => {
+        const keys = key.split('.');
+        let value = translations[language];
+
+        for (const k of keys) {
+            if (value && typeof value === 'object') {
+                value = value[k];
+            } else {
+                return key; // fallback to key if not found
+            }
+        }
+
+        if (typeof value !== 'string') return key;
+
+        // Replace {param} placeholders
+        return value.replace(/\{(\w+)\}/g, (_, param) =>
+            params[param] !== undefined ? params[param] : `{${param}}`
+        );
+    }, [language]);
+
+    const value = useMemo(() => ({
+        language,
+        setLanguage,
+        t
+    }), [language, setLanguage, t]);
+
+    return (
+        <I18nContext.Provider value={value}>
+            {children}
+        </I18nContext.Provider>
+    );
+}
+
+export function useI18n() {
+    const context = useContext(I18nContext);
+    if (!context) {
+        throw new Error('useI18n must be used within an I18nProvider');
+    }
+    return context;
+}

src/client/LanguageSwitcher.js

@@ -0,0 +1,42 @@
+import React from 'react';
+import { Box, IconButton, Tooltip } from '@mui/material';
+import { useI18n } from './I18nContext';
+
+// Flag emojis for language switching
+const FLAG_DE = '🇩🇪';
+const FLAG_EN = '🇬🇧';
+
+export default function LanguageSwitcher() {
+    const { language, setLanguage } = useI18n();
+
+    return (
+        <Box sx={{ display: 'flex', gap: 0.5 }}>
+            <Tooltip title="English">
+                <IconButton
+                    size="small"
+                    onClick={() => setLanguage('en')}
+                    sx={{
+                        opacity: language === 'en' ? 1 : 0.5,
+                        fontSize: '1.2rem',
+                        '&:hover': { opacity: 1 }
+                    }}
+                >
+                    {FLAG_EN}
+                </IconButton>
+            </Tooltip>
+            <Tooltip title="Deutsch">
+                <IconButton
+                    size="small"
+                    onClick={() => setLanguage('de')}
+                    sx={{
+                        opacity: language === 'de' ? 1 : 0.5,
+                        fontSize: '1.2rem',
+                        '&:hover': { opacity: 1 }
+                    }}
+                >
+                    {FLAG_DE}
+                </IconButton>
+            </Tooltip>
+        </Box>
+    );
+}

src/client/LoginDialog.js

@@ -14,6 +14,7 @@ import {
     Typography
 } from '@mui/material';
 import { useAuth } from './AuthContext';
+import { useI18n } from './I18nContext';
 
 // Simple eye icons using unicode
 const VisibilityIcon = () => <span style={{ fontSize: '1.2rem' }}>👁</span>;
@@ -21,6 +22,7 @@ const VisibilityOffIcon = () => <span style={{ fontSize: '1.2rem' }}>👁‍🗨
 
 export default function LoginDialog({ open, onClose }) {
     const { login } = useAuth();
+    const { t } = useI18n();
     const [username, setUsername] = useState('');
     const [password, setPassword] = useState('');
     const [showPassword, setShowPassword] = useState(false);
@@ -66,10 +68,10 @@ export default function LoginDialog({ open, onClose }) {
         >
             <DialogTitle sx={{ textAlign: 'center', pb: 1 }}>
                 <Typography variant="h5" component="div" sx={{ fontWeight: 600 }}>
-                    🔐 Dashboard Login
+                    {t('login.title')}
                 </Typography>
                 <Typography variant="body2" color="text.secondary" sx={{ mt: 1 }}>
-                    Tischlerei Automation Control
+                    {t('login.subtitle')}
                 </Typography>
             </DialogTitle>
 
@@ -84,7 +86,7 @@ export default function LoginDialog({ open, onClose }) {
                     <TextField
                         autoFocus
                         margin="dense"
-                        label="Username"
+                        label={t('login.username')}
                         type="text"
                         fullWidth
                         variant="outlined"
@@ -96,7 +98,7 @@ export default function LoginDialog({ open, onClose }) {
 
                     <TextField
                         margin="dense"
-                        label="Password"
+                        label={t('login.password')}
                         type={showPassword ? 'text' : 'password'}
                         fullWidth
                         variant="outlined"
@@ -137,10 +139,10 @@ export default function LoginDialog({ open, onClose }) {
                         {loading ? (
                             <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
                                 <CircularProgress size={20} color="inherit" />
-                                <span>Signing in...</span>
+                                <span>{t('login.signingIn')}</span>
                             </Box>
                         ) : (
-                            'Sign In'
+                            t('login.signIn')
                         )}
                     </Button>
                 </DialogActions>

src/client/RuleCard.js

@@ -8,15 +8,25 @@ import {
     Chip,
     Tooltip
 } from '@mui/material';
+import { useI18n } from './I18nContext';
 
 // Simple icons using unicode/emoji
 const EditIcon = () => <span style={{ fontSize: '1rem' }}>✏️</span>;
 const DeleteIcon = () => <span style={{ fontSize: '1rem' }}>🗑️</span>;
 
-const dayLabels = { mon: 'M', tue: 'T', wed: 'W', thu: 'T', fri: 'F', sat: 'S', sun: 'S' };
 const dayOrder = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'];
 
 function TriggerSummary({ trigger }) {
+    const { t } = useI18n();
+    const dayLabels = {
+        mon: t('days.mon').charAt(0),
+        tue: t('days.tue').charAt(0),
+        wed: t('days.wed').charAt(0),
+        thu: t('days.thu').charAt(0),
+        fri: t('days.fri').charAt(0),
+        sat: t('days.sat').charAt(0),
+        sun: t('days.sun').charAt(0)
+    };
     const parts = [];
 
     // Scheduled time (trigger at exact time)
@@ -24,14 +34,14 @@ function TriggerSummary({ trigger }) {
         const { time, days } = trigger.scheduledTime;
         const isEveryDay = days?.length === 7;
         const isWeekdays = days?.length === 5 && ['mon', 'tue', 'wed', 'thu', 'fri'].every(d => days.includes(d));
-        let dayText = isEveryDay ? 'daily' : isWeekdays ? 'weekdays' :
+        let dayText = isEveryDay ? t('ruleCard.daily') : isWeekdays ? t('ruleCard.weekdays') :
             dayOrder.filter(d => days?.includes(d)).map(d => dayLabels[d]).join('');
 
         parts.push(
             <Box key="scheduled" sx={{ display: 'flex', alignItems: 'center', gap: 0.5, flexWrap: 'wrap' }}>
                 <Chip label="🕐" size="small" sx={{ bgcolor: '#d3869b', color: '#282828', fontWeight: 600, minWidth: 32 }} />
                 <Typography variant="body2">
-                    At <strong>{time}</strong> ({dayText})
+                    {t('ruleCard.at')} <strong>{time}</strong> ({dayText})
                 </Typography>
             </Box>
         );
@@ -42,7 +52,7 @@ function TriggerSummary({ trigger }) {
         const { start, end, days } = trigger.timeRange;
         const isEveryDay = days?.length === 7;
         const isWeekdays = days?.length === 5 && ['mon', 'tue', 'wed', 'thu', 'fri'].every(d => days.includes(d));
-        let dayText = isEveryDay ? 'daily' : isWeekdays ? 'weekdays' :
+        let dayText = isEveryDay ? t('ruleCard.daily') : isWeekdays ? t('ruleCard.weekdays') :
             dayOrder.filter(d => days?.includes(d)).map(d => dayLabels[d]).join('');
 
         parts.push(
@@ -80,13 +90,13 @@ function TriggerSummary({ trigger }) {
         const days = trigger.days || [];
         const isEveryDay = days.length === 7;
         const isWeekdays = days.length === 5 && ['mon', 'tue', 'wed', 'thu', 'fri'].every(d => days.includes(d));
-        let dayText = isEveryDay ? 'daily' : isWeekdays ? 'weekdays' :
+        let dayText = isEveryDay ? t('ruleCard.daily') : isWeekdays ? t('ruleCard.weekdays') :
             dayOrder.filter(d => days.includes(d)).map(d => dayLabels[d]).join(' ');
 
         parts.push(
             <Box key="legacy-time" sx={{ display: 'flex', alignItems: 'center', gap: 0.5 }}>
                 <Chip label="⏰" size="small" sx={{ bgcolor: '#83a598', color: '#282828', fontWeight: 600 }} />
-                <Typography variant="body2">At {trigger.time} ({dayText})</Typography>
+                <Typography variant="body2">{t('ruleCard.at')} {trigger.time} ({dayText})</Typography>
             </Box>
         );
     }
@@ -112,6 +122,8 @@ function TriggerSummary({ trigger }) {
 }
 
 function ActionSummary({ action }) {
+    const { t } = useI18n();
+
     if (action.type === 'toggle') {
         // Check if it's a level or binary action
         const hasLevel = action.level !== undefined;
@@ -123,7 +135,7 @@ function ActionSummary({ action }) {
                     sx={{ bgcolor: hasLevel ? '#83a598' : (action.state ? '#b8bb26' : '#fb4934'), color: '#282828', fontWeight: 600, minWidth: 32 }}
                 />
                 <Typography variant="body2">
-                    → <strong>{action.targetLabel || action.target}</strong> {hasLevel ? `Level ${action.level}` : (action.state ? 'ON' : 'OFF')}
+                    → <strong>{action.targetLabel || action.target}</strong> {hasLevel ? `${t('ruleCard.level')} ${action.level}` : (action.state ? t('ruleCard.on') : t('ruleCard.off'))}
                 </Typography>
             </Box>
         );
@@ -135,7 +147,7 @@ function ActionSummary({ action }) {
             <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.5 }}>
                 <Chip label="⏱️" size="small" sx={{ bgcolor: '#d3869b', color: '#282828', fontWeight: 600, minWidth: 32 }} />
                 <Typography variant="body2">
-                    → <strong>{action.targetLabel || action.target}</strong> {hasLevel ? `Level ${action.level}` : 'ON'} for {action.duration}m
+                    → <strong>{action.targetLabel || action.target}</strong> {hasLevel ? `${t('ruleCard.level')} ${action.level}` : t('ruleCard.on')} {t('ruleCard.forMinutes', { duration: action.duration })}
                 </Typography>
             </Box>
         );
@@ -145,6 +157,7 @@ function ActionSummary({ action }) {
 }
 
 export default function RuleCard({ rule, onEdit, onDelete, onToggle, onMoveUp, onMoveDown, colorTags = [], readOnly }) {
+    const { t } = useI18n();
     // Get list of tag colors for this rule (handle array or backwards-compat single value)
     const ruleTagIds = rule.colorTags || (rule.colorTag ? [rule.colorTag] : []);
     const ruleTags = ruleTagIds.map(tagId => colorTags.find(t => t.id === tagId)).filter(Boolean);
@@ -184,7 +197,7 @@ export default function RuleCard({ rule, onEdit, onDelete, onToggle, onMoveUp, o
                             </Box>
                         )}
                         {!rule.enabled && (
-                            <Chip label="Disabled" size="small" sx={{ bgcolor: '#504945', fontSize: '0.7rem' }} />
+                            <Chip label={t('ruleCard.disabled')} size="small" sx={{ bgcolor: '#504945', fontSize: '0.7rem' }} />
                         )}
                     </Box>
 
@@ -223,13 +236,13 @@ export default function RuleCard({ rule, onEdit, onDelete, onToggle, onMoveUp, o
                                 </span>
                             </Tooltip>
                         </Box>
-                        <Tooltip title={rule.enabled ? 'Disable' : 'Enable'}>
+                        <Tooltip title={rule.enabled ? t('ruleCard.disable') : t('ruleCard.enable')}>
                             <Switch checked={rule.enabled} onChange={onToggle} color="primary" size="small" />
                         </Tooltip>
-                        <Tooltip title="Edit">
+                        <Tooltip title={t('ruleCard.edit')}>
                             <IconButton onClick={onEdit} size="small"><EditIcon /></IconButton>
                         </Tooltip>
-                        <Tooltip title="Delete">
+                        <Tooltip title={t('ruleCard.delete')}>
                             <IconButton onClick={onDelete} size="small" sx={{ '&:hover': { color: '#fb4934' } }}>
                                 <DeleteIcon />
                             </IconButton>

src/client/RuleEditor.js

@@ -23,16 +23,9 @@ import {
     Paper,
     Chip
 } from '@mui/material';
+import { useI18n } from './I18nContext';
 
-const DAYS = [
+const DAYS_KEYS = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'];
-    { key: 'mon', label: 'Mon' },
-    { key: 'tue', label: 'Tue' },
-    { key: 'wed', label: 'Wed' },
-    { key: 'thu', label: 'Thu' },
-    { key: 'fri', label: 'Fri' },
-    { key: 'sat', label: 'Sat' },
-    { key: 'sun', label: 'Sun' }
-];
 
 const OPERATORS = [
     { value: '>', label: '>' },
@@ -122,6 +115,7 @@ function SensorCondition({ condition, sensors, onChange, onRemove, disabled }) {
 }
 
 export default function RuleEditor({ open, rule, onSave, onClose, sensors = [], outputs = [], colorTags: availableColorTags = [], saving }) {
+    const { t } = useI18n();
     const [name, setName] = useState('');
     const [selectedTags, setSelectedTags] = useState([]); // array of tag ids
 
@@ -312,18 +306,18 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
             }}
         >
             <DialogTitle>
-                {rule ? '✏️ Edit Rule' : '➕ Create New Rule'}
+                {rule ? t('ruleEditor.editTitle') : t('ruleEditor.createTitle')}
             </DialogTitle>
 
             <DialogContent dividers>
                 <Box sx={{ display: 'flex', flexDirection: 'column', gap: 3, pt: 1 }}>
                     {/* Rule Name */}
                     <TextField
-                        label="Rule Name"
+                        label={t('ruleEditor.ruleName')}
                         value={name}
                         onChange={(e) => setName(e.target.value)}
                         fullWidth
-                        placeholder="e.g., Daytime High Humidity Fan"
+                        placeholder={t('ruleEditor.ruleNamePlaceholder')}
                         disabled={saving}
                     />
 
@@ -379,7 +373,7 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
                     {/* TRIGGERS SECTION */}
                     <Box>
                         <Typography variant="subtitle2" color="text.secondary" gutterBottom>
-                            TRIGGERS (When to activate)
+                            {t('ruleEditor.triggersSection')}
                         </Typography>
                         <Divider sx={{ mb: 2 }} />
 
@@ -393,13 +387,13 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
                                         disabled={saving}
                                     />
                                 }
-                                label={<Typography fontWeight={600}>🕐 Scheduled Time (trigger at exact time)</Typography>}
+                                label={<Typography fontWeight={600}>{t('ruleEditor.scheduledTime')}</Typography>}
                             />
 
                             {useScheduledTime && (
                                 <Box sx={{ mt: 2, display: 'flex', flexDirection: 'column', gap: 2 }}>
                                     <TextField
-                                        label="Trigger At"
+                                        label={t('ruleEditor.triggerAt')}
                                         type="time"
                                         value={scheduledTime}
                                         onChange={(e) => setScheduledTime(e.target.value)}
@@ -410,7 +404,7 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
                                     />
                                     <Box>
                                         <Typography variant="body2" color="text.secondary" sx={{ mb: 1 }}>
-                                            Days
+                                            {t('ruleEditor.days')}
                                         </Typography>
                                         <ToggleButtonGroup
                                             value={scheduledDays}
@@ -418,10 +412,10 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
                                             size="small"
                                             disabled={saving}
                                         >
-                                            {DAYS.map(day => (
+                                            {DAYS_KEYS.map(key => (
                                                 <ToggleButton
-                                                    key={day.key}
+                                                    key={key}
-                                                    value={day.key}
+                                                    value={key}
                                                     sx={{
                                                         '&.Mui-selected': {
                                                             bgcolor: '#d3869b',
@@ -430,7 +424,7 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
                                                         }
                                                     }}
                                                 >
-                                                    {day.label}
+                                                    {t(`days.${key}`)}
                                                 </ToggleButton>
                                             ))}
                                         </ToggleButtonGroup>
@@ -477,7 +471,7 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
                                     </Box>
                                     <Box>
                                         <Typography variant="body2" color="text.secondary" sx={{ mb: 1 }}>
-                                            Days
+                                            {t('ruleEditor.days')}
                                         </Typography>
                                         <ToggleButtonGroup
                                             value={timeRangeDays}
@@ -485,10 +479,10 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
                                             size="small"
                                             disabled={saving}
                                         >
-                                            {DAYS.map(day => (
+                                            {DAYS_KEYS.map(key => (
                                                 <ToggleButton
-                                                    key={day.key}
+                                                    key={key}
-                                                    value={day.key}
+                                                    value={key}
                                                     sx={{
                                                         '&.Mui-selected': {
                                                             bgcolor: '#8ec07c',
@@ -497,7 +491,7 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
                                                         }
                                                     }}
                                                 >
-                                                    {day.label}
+                                                    {t(`days.${key}`)}
                                                 </ToggleButton>
                                             ))}
                                         </ToggleButtonGroup>
@@ -709,7 +703,7 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
 
             <DialogActions sx={{ px: 3, py: 2 }}>
                 <Button onClick={onClose} color="inherit" disabled={saving}>
-                    Cancel
+                    {t('ruleEditor.cancel')}
                 </Button>
                 <Button
                     onClick={handleSave}
@@ -725,10 +719,10 @@ export default function RuleEditor({ open, rule, onSave, onClose, sensors = [],
                     {saving ? (
                         <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
                             <CircularProgress size={16} color="inherit" />
-                            Saving...
+                            {t('ruleEditor.saving')}
                         </Box>
                     ) : (
-                        rule ? 'Save Changes' : 'Create Rule'
+                        rule ? t('ruleEditor.saveChanges') : t('ruleEditor.createRule')
                     )}
                 </Button>
             </DialogActions>

src/client/RuleManager.js

@@ -13,6 +13,7 @@ import {
 import RuleCard from './RuleCard';
 import RuleEditor from './RuleEditor';
 import { useAuth } from './AuthContext';
+import { useI18n } from './I18nContext';
 
 // 8 color tags
 const COLOR_TAGS = [
@@ -28,6 +29,7 @@ const COLOR_TAGS = [
 
 export default function RuleManager() {
     const { isAdmin } = useAuth();
+    const { t } = useI18n();
     const [rules, setRules] = useState([]);
     const [loading, setLoading] = useState(true);
     const [error, setError] = useState(null);
@@ -152,7 +154,7 @@ export default function RuleManager() {
     };
 
     const handleDeleteRule = async (ruleId) => {
-        if (!confirm('Delete this rule?')) return;
+        if (!confirm(t('rules.deleteConfirm'))) return;
 
         setSaving(true);
         try {
@@ -262,7 +264,7 @@ export default function RuleManager() {
         return (
             <Paper sx={{ mt: 4, p: 3, textAlign: 'center' }}>
                 <CircularProgress size={24} />
-                <Typography sx={{ mt: 2 }}>Loading rules...</Typography>
+                <Typography sx={{ mt: 2 }}>{t('rules.loading')}</Typography>
             </Paper>
         );
     }
@@ -279,10 +281,10 @@ export default function RuleManager() {
             <Box sx={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', mb: 2 }}>
                 <Box>
                     <Typography variant="h5" sx={{ fontWeight: 600, display: 'flex', alignItems: 'center', gap: 1 }}>
-                        ⚙️ Automation Rules
+                        {t('rules.title')}
                     </Typography>
                     <Typography variant="body2" color="text.secondary">
-                        {isAdmin ? 'Configure triggers and actions for home automation' : 'View automation rules (read-only)'}
+                        {isAdmin ? t('rules.adminDescription') : t('rules.guestDescription')}
                     </Typography>
                 </Box>
                 {isAdmin && (
@@ -297,7 +299,7 @@ export default function RuleManager() {
                             }
                         }}
                     >
-                        + Add Rule
+                        {t('rules.addRule')}
                     </Button>
                 )}
             </Box>
@@ -341,7 +343,7 @@ export default function RuleManager() {
                 <Box sx={{ textAlign: 'center', py: 4 }}>
                     <Typography color="text.secondary">
                         {rules.length === 0
-                            ? (isAdmin ? 'No rules configured. Click "Add Rule" to create one.' : 'No rules configured.')
+                            ? (isAdmin ? t('rules.noRules') + ' ' + t('rules.noRulesAdmin') : t('rules.noRules'))
                             : 'No rules match the selected filter.'
                         }
                     </Typography>

src/client/i18n/de.json

@@ -0,0 +1,94 @@
+{
+    "app": {
+        "title": "Tischlerei Dashboard",
+        "adminLogin": "🔐 Admin Anmeldung",
+        "logout": "Abmelden",
+        "admin": "ADMIN"
+    },
+    "dashboard": {
+        "loading": "Geräte werden geladen...",
+        "hours24": "24 Stunden",
+        "days7": "7 Tage",
+        "days30": "30 Tage"
+    },
+    "login": {
+        "title": "🔐 Dashboard Anmeldung",
+        "subtitle": "Tischlerei Automatisierungssteuerung",
+        "username": "Benutzername",
+        "password": "Passwort",
+        "signIn": "Anmelden",
+        "signingIn": "Anmeldung läuft..."
+    },
+    "controller": {
+        "environment": "Umgebung (Temp. / Luftfeuchtigkeit)",
+        "port": "Anschluss"
+    },
+    "rules": {
+        "title": "⚙️ Automatisierungsregeln",
+        "adminDescription": "Trigger und Aktionen für die Hausautomatisierung konfigurieren",
+        "guestDescription": "Automatisierungsregeln ansehen (nur Lesen)",
+        "addRule": "+ Regel hinzufügen",
+        "loading": "Regeln werden geladen...",
+        "noRules": "Keine Regeln konfiguriert.",
+        "noRulesAdmin": "Klicken Sie auf \"Regel hinzufügen\" um eine zu erstellen.",
+        "deleteConfirm": "Diese Regel löschen?"
+    },
+    "ruleCard": {
+        "disabled": "Deaktiviert",
+        "enable": "Aktivieren",
+        "disable": "Deaktivieren",
+        "edit": "Bearbeiten",
+        "delete": "Löschen",
+        "daily": "täglich",
+        "weekdays": "werktags",
+        "at": "Um",
+        "level": "Stufe",
+        "on": "AN",
+        "off": "AUS",
+        "forMinutes": "für {duration}m",
+        "isOn": "ist AN",
+        "isOff": "ist AUS"
+    },
+    "ruleEditor": {
+        "editTitle": "✏️ Regel bearbeiten",
+        "createTitle": "➕ Neue Regel erstellen",
+        "ruleName": "Regelname",
+        "ruleNamePlaceholder": "z.B. Tagsüber Hohe Luftfeuchtigkeit Lüfter",
+        "triggersSection": "AUSLÖSER (Wann aktivieren)",
+        "actionSection": "AKTION (Was tun)",
+        "scheduledTime": "🕐 Geplante Zeit (zu exakter Zeit auslösen)",
+        "triggerAt": "Auslösen um",
+        "timeRange": "⏰ Zeitbereich (aktiv während Fenster)",
+        "from": "Von",
+        "to": "bis",
+        "until": "Bis",
+        "days": "Tage",
+        "sensorConditions": "📊 Sensorbedingungen",
+        "noSensors": "(keine Sensoren verfügbar)",
+        "combineWith": "Bedingungen verknüpfen mit:",
+        "addCondition": "+ Bedingung hinzufügen",
+        "sensor": "Sensor",
+        "actionType": "Aktionstyp",
+        "toggleOnOff": "🔛 Ein/Aus schalten",
+        "keepOnMinutes": "⏱️ Für X Minuten eingeschaltet lassen",
+        "targetOutput": "Zielausgang",
+        "turnOn": "Einschalten",
+        "turnOff": "Ausschalten",
+        "setLevel": "Stufe setzen:",
+        "duration": "Dauer:",
+        "minutes": "Minuten",
+        "cancel": "Abbrechen",
+        "saveChanges": "Änderungen speichern",
+        "createRule": "Regel erstellen",
+        "saving": "Speichern..."
+    },
+    "days": {
+        "mon": "Mo",
+        "tue": "Di",
+        "wed": "Mi",
+        "thu": "Do",
+        "fri": "Fr",
+        "sat": "Sa",
+        "sun": "So"
+    }
+}

src/client/i18n/en.json

@@ -0,0 +1,94 @@
+{
+    "app": {
+        "title": "Tischlerei Dashboard",
+        "adminLogin": "🔐 Admin Login",
+        "logout": "Logout",
+        "admin": "ADMIN"
+    },
+    "dashboard": {
+        "loading": "Loading devices...",
+        "hours24": "24 Hours",
+        "days7": "7 Days",
+        "days30": "30 Days"
+    },
+    "login": {
+        "title": "🔐 Dashboard Login",
+        "subtitle": "Tischlerei Automation Control",
+        "username": "Username",
+        "password": "Password",
+        "signIn": "Sign In",
+        "signingIn": "Signing in..."
+    },
+    "controller": {
+        "environment": "Environment (Temp / Humidity)",
+        "port": "Port"
+    },
+    "rules": {
+        "title": "⚙️ Automation Rules",
+        "adminDescription": "Configure triggers and actions for home automation",
+        "guestDescription": "View automation rules (read-only)",
+        "addRule": "+ Add Rule",
+        "loading": "Loading rules...",
+        "noRules": "No rules configured.",
+        "noRulesAdmin": "Click \"Add Rule\" to create one.",
+        "deleteConfirm": "Delete this rule?"
+    },
+    "ruleCard": {
+        "disabled": "Disabled",
+        "enable": "Enable",
+        "disable": "Disable",
+        "edit": "Edit",
+        "delete": "Delete",
+        "daily": "daily",
+        "weekdays": "weekdays",
+        "at": "At",
+        "level": "Level",
+        "on": "ON",
+        "off": "OFF",
+        "forMinutes": "for {duration}m",
+        "isOn": "is ON",
+        "isOff": "is OFF"
+    },
+    "ruleEditor": {
+        "editTitle": "✏️ Edit Rule",
+        "createTitle": "➕ Create New Rule",
+        "ruleName": "Rule Name",
+        "ruleNamePlaceholder": "e.g., Daytime High Humidity Fan",
+        "triggersSection": "TRIGGERS (When to activate)",
+        "actionSection": "ACTION (What to do)",
+        "scheduledTime": "🕐 Scheduled Time (trigger at exact time)",
+        "triggerAt": "Trigger At",
+        "timeRange": "⏰ Time Range (active during window)",
+        "from": "From",
+        "to": "to",
+        "until": "Until",
+        "days": "Days",
+        "sensorConditions": "📊 Sensor Conditions",
+        "noSensors": "(no sensors available)",
+        "combineWith": "Combine conditions with:",
+        "addCondition": "+ Add Condition",
+        "sensor": "Sensor",
+        "actionType": "Action Type",
+        "toggleOnOff": "🔛 Toggle On/Off",
+        "keepOnMinutes": "⏱️ Keep On for X Minutes",
+        "targetOutput": "Target Output",
+        "turnOn": "Turn ON",
+        "turnOff": "Turn OFF",
+        "setLevel": "Set Level:",
+        "duration": "Duration:",
+        "minutes": "minutes",
+        "cancel": "Cancel",
+        "saveChanges": "Save Changes",
+        "createRule": "Create Rule",
+        "saving": "Saving..."
+    },
+    "days": {
+        "mon": "Mon",
+        "tue": "Tue",
+        "wed": "Wed",
+        "thu": "Thu",
+        "fri": "Fri",
+        "sat": "Sat",
+        "sun": "Sun"
+    }
+}