'use client';

import {
  createContext,
  useContext,
  useEffect,
  useState,
  ReactNode,
  useMemo,
} from 'react';

type Language = 'de' | 'en';

const translations = {
  de: {
    // App + Navigation
    appName: 'PATCHPILOT',
    tools: 'Werkzeuge',
    chat: 'KI-Assistent',
    admin: 'Admin',
    logout: 'Abmelden',
    administrator: 'Administrator',
    guestRole: 'Gast',
    staffRole: 'Mitarbeiter',
    user: 'Nutzer',
    role: 'Rolle',

    // Hero
    heroBadge: 'KI-gestützte Reparaturlösungen',
    heroTitlePart1: 'Repariere klüger,',
    heroTitlePart2: 'nicht härter.',
    heroSubtitle:
      'Dein intelligenter Begleiter für jede Reparatur. Erhalte Schritt-für-Schritt Anleitungen, Werkzeug-Empfehlungen und sofortige Hilfe.',
    heroCTA: 'Jetzt Hilfe anfordern',
    aiPlaceholder: 'Frage RepairBuddy nach Hilfe…',
    miniStatInventory: 'Inventar',
    miniStatAssistant: 'KI-Assistent',
    miniStatResponse: 'Antwort',

    // Login
    loginWelcomeBack: 'Willkommen zurück',
    loginSubtitle:
      'Melde dich an, um Werkzeuge zu reservieren und mit dem KI-Assistenten zu chatten.',
    loginDemoTitle: 'Demo-Zugänge',
    loginDemoBody:
      'admin / admin · vollständiger Zugriff\nguest / guest · Gast-Modus\nstaff / staff · Mitarbeiter',
    loginError: 'Falscher Benutzername oder Passwort. (Tipp: admin/admin oder guest/guest)',
    loginSubmit: 'Einloggen',
    loginSubmitting: 'Einloggen…',

    // Tools page
    inventory: 'Werkzeug-Inventar',
    inventoryHint: 'Werkzeuge verfügbar',
    search: 'Werkzeuge durchsuchen…',
    filter: 'Filter',
    all: 'Alle',
    reserve: 'Jetzt reservieren',
    certified: 'Zertifiziert',
    trainingMissing: 'Schulung fehlt',
    trainingRequired: 'Einweisung benötigt',
    homeUse: 'Heimnutzung',
    freeAccess: 'Frei zugänglich',
    days: 'Tage',
    noToolsFound: 'Keine Werkzeuge gefunden. Passe Suche oder Filter an.',

    // Chat
    newChat: 'Neuer Chat',
    chatHistory: 'Verlauf',
    chatEmptyTitle: 'Womit darf ich helfen?',
    chatEmptyHint:
      'Frag mich nach Werkzeugen, Reparatur-Tipps oder beschreibe dein Problem.',
    chatNoSessionTitle: 'Worüber sollen wir reden?',
    chatNoSessionHint: 'Wähle einen Vorschlag unten oder schreibe deine Frage.',
    chatRename: 'Umbenennen',
    chatDelete: 'Löschen',
    chatRetry: 'Letzte Anfrage erneut senden',
    chatCopy: 'Kopieren',
    chatCopied: 'Kopiert!',
    chatTypingPlaceholder: 'Tippe deine Frage…',
    modeLive: 'Live',
    modeFallback: 'Fallback',
    modeDemo: 'Demo',

    // Reservation
    reservation: 'Reservierung',
    availability: 'Verfügbarkeit',
    booked: 'Reserviert',
    free: 'Frei',
    from: 'Von',
    to: 'Bis',
    maxRental: 'Maximale Leihdauer',
    cancel: 'Abbrechen',
    request: 'Anfragen',
    confirmReservation: 'Reservieren',
    reservedSuccess: 'Reserviert!',
    durationTotal: 'gesamt',
    notice:
      'Bitte bringe das Werkzeug rechtzeitig und unbeschädigt zurück.',

    // Login form fields
    username: 'Benutzername',
    password: 'Passwort',
    login: 'Einloggen',

    // Onboarding
    welcome: 'Willkommen bei PatchPilot!',
    onboarding1Desc:
      'Hier kannst du professionelle Werkzeuge für deine Reparaturen ausleihen. Achte auf die Einweisungspflicht!',
    onboarding2Title: 'Dein Reparatur-Assistent',
    onboarding2Desc:
      'Nutze unseren Chatbot, um Tipps für deine Reparatur zu bekommen oder das passende Werkzeug zu finden.',
    onboarding3Title: 'Verfügbarkeit prüfen',
    onboarding3Desc:
      'In unserem interaktiven Kalender siehst du sofort, wann Werkzeuge verfügbar sind.',
    onboarding4Title: 'Admin-Funktionen',
    onboarding4Desc:
      'Als Administrator kannst du das gesamte System verwalten — von Werkzeugen bis hin zu KI-Wissensquellen.',
    getStarted: 'Loslegen',
    next: 'Weiter',
    back: 'Zurück',
    skip: 'Überspringen',
    onboardingStep: 'Schritt',
    of: 'von',

    // Admin
    adminDashboard: 'Admin Dashboard',
    adminSubtitle: 'Verwalte Werkzeuge, Reservierungen und Wissen',
    manageTools: 'Werkzeuge',
    manageRAG: 'KI-Wissen',
    manageUsers: 'Nutzer',
    calendar: 'Kalender',
    addTool: 'Werkzeug hinzufügen',
    editTool: 'Werkzeug bearbeiten',
    deleteTool: 'Werkzeug löschen',
    confirmDelete: 'Wirklich löschen?',
    delete: 'Löschen',
    edit: 'Bearbeiten',
    save: 'Speichern',
    name: 'Name',
    description: 'Beschreibung',
    location: 'Standort',
    category: 'Kategorie',
    emoji: 'Symbol',
    status: 'Status',
    actions: 'Aktionen',
    available: 'Verfügbar',
    statsTools: 'Werkzeuge',
    statsUsers: 'Nutzer',
    statsActive: 'Aktive Reservierungen',
    statsPending: 'Offen',
    addManual: 'Dokument hochladen',
    manualPreview: 'Vorschau',
    forTool: 'Werkzeug',
    title: 'Titel',
    content: 'Inhalt',
    certifications: 'Zertifizierungen',
    none: 'keine',
    pendingReservations: 'Offene Reservierungs-Anfragen',
    approve: 'Genehmigen',
    reject: 'Ablehnen',
    requestedBy: 'Angefragt von',
    period: 'Zeitraum',
    statusRequested: 'Angefragt',
    statusApproved: 'Genehmigt',
    statusActive: 'Aktiv',
    statusCompleted: 'Erledigt',
    statusOverdue: 'Überfällig',
    reservationCalendar: 'Reservierungskalender',
  },
  en: {
    // App + Navigation
    appName: 'PATCHPILOT',
    tools: 'Tools',
    chat: 'AI Assistant',
    admin: 'Admin',
    logout: 'Sign out',
    administrator: 'Administrator',
    guestRole: 'Guest',
    staffRole: 'Staff',
    user: 'User',
    role: 'Role',

    // Hero
    heroBadge: 'AI-powered repair solutions',
    heroTitlePart1: 'Repair smarter,',
    heroTitlePart2: 'not harder.',
    heroSubtitle:
      'Your intelligent companion for every repair. Get step-by-step instructions, tool recommendations, and instant help.',
    heroCTA: 'Get help now',
    aiPlaceholder: 'Ask RepairBuddy for help…',
    miniStatInventory: 'Inventory',
    miniStatAssistant: 'AI assistant',
    miniStatResponse: 'Response',

    // Login
    loginWelcomeBack: 'Welcome back',
    loginSubtitle:
      'Sign in to reserve tools and chat with the AI assistant.',
    loginDemoTitle: 'Demo accounts',
    loginDemoBody:
      'admin / admin · full access\nguest / guest · guest mode\nstaff / staff · staff member',
    loginError: 'Wrong username or password. (Hint: admin/admin or guest/guest)',
    loginSubmit: 'Sign in',
    loginSubmitting: 'Signing in…',

    // Tools page
    inventory: 'Tool Inventory',
    inventoryHint: 'tools available',
    search: 'Search tools…',
    filter: 'Filter',
    all: 'All',
    reserve: 'Reserve now',
    certified: 'Certified',
    trainingMissing: 'Training missing',
    trainingRequired: 'Training required',
    homeUse: 'Home use',
    freeAccess: 'Free access',
    days: 'days',
    noToolsFound: 'No tools found. Adjust your search or filter.',

    // Chat
    newChat: 'New chat',
    chatHistory: 'History',
    chatEmptyTitle: 'How can I help?',
    chatEmptyHint:
      'Ask me about tools, repair tips, or describe your problem.',
    chatNoSessionTitle: 'What shall we talk about?',
    chatNoSessionHint: 'Pick a suggestion below or type your question.',
    chatRename: 'Rename',
    chatDelete: 'Delete',
    chatRetry: 'Retry last request',
    chatCopy: 'Copy',
    chatCopied: 'Copied!',
    chatTypingPlaceholder: 'Type your question…',
    modeLive: 'Live',
    modeFallback: 'Fallback',
    modeDemo: 'Demo',

    // Reservation
    reservation: 'Reservation',
    availability: 'Availability',
    booked: 'Booked',
    free: 'Free',
    from: 'From',
    to: 'To',
    maxRental: 'Max rental period',
    cancel: 'Cancel',
    request: 'Request',
    confirmReservation: 'Reserve',
    reservedSuccess: 'Reserved!',
    durationTotal: 'total',
    notice: 'Please return the tool on time and undamaged.',

    // Login form fields
    username: 'Username',
    password: 'Password',
    login: 'Sign in',

    // Onboarding
    welcome: 'Welcome to PatchPilot!',
    onboarding1Desc:
      'Here you can rent professional tools for your repairs. Mind the training requirements!',
    onboarding2Title: 'Your repair assistant',
    onboarding2Desc:
      'Use our chatbot to get tips for your repair or find the right tool.',
    onboarding3Title: 'Check availability',
    onboarding3Desc:
      'See exactly when tools are available in our interactive calendar.',
    onboarding4Title: 'Admin features',
    onboarding4Desc:
      'As an administrator, you can manage the entire system — from tools to AI knowledge sources.',
    getStarted: 'Get started',
    next: 'Next',
    back: 'Back',
    skip: 'Skip',
    onboardingStep: 'Step',
    of: 'of',

    // Admin
    adminDashboard: 'Admin Dashboard',
    adminSubtitle: 'Manage tools, reservations, and knowledge',
    manageTools: 'Tools',
    manageRAG: 'AI Knowledge',
    manageUsers: 'Users',
    calendar: 'Calendar',
    addTool: 'Add tool',
    editTool: 'Edit tool',
    deleteTool: 'Delete tool',
    confirmDelete: 'Really delete?',
    delete: 'Delete',
    edit: 'Edit',
    save: 'Save',
    name: 'Name',
    description: 'Description',
    location: 'Location',
    category: 'Category',
    emoji: 'Symbol',
    status: 'Status',
    actions: 'Actions',
    available: 'Available',
    statsTools: 'Tools',
    statsUsers: 'Users',
    statsActive: 'Active reservations',
    statsPending: 'Pending',
    addManual: 'Upload manual',
    manualPreview: 'Preview',
    forTool: 'Tool',
    title: 'Title',
    content: 'Content',
    certifications: 'Certifications',
    none: 'none',
    pendingReservations: 'Pending reservation requests',
    approve: 'Approve',
    reject: 'Reject',
    requestedBy: 'Requested by',
    period: 'Period',
    statusRequested: 'Requested',
    statusApproved: 'Approved',
    statusActive: 'Active',
    statusCompleted: 'Completed',
    statusOverdue: 'Overdue',
    reservationCalendar: 'Reservation calendar',
  },
} as const;

type TranslationKey = keyof (typeof translations)['de'];

interface I18nContextType {
  t: (key: TranslationKey) => string;
  lang: Language;
  setLang: (lang: Language) => void;
}

const I18nContext = createContext<I18nContextType | undefined>(undefined);

const STORAGE_KEY = 'patchpilot:lang';

function detectInitialLang(): Language {
  if (typeof window === 'undefined') return 'de';
  const stored = window.localStorage.getItem(STORAGE_KEY);
  if (stored === 'de' || stored === 'en') return stored;
  const browser = window.navigator.language.toLowerCase();
  return browser.startsWith('en') ? 'en' : 'de';
}

export function I18nProvider({ children }: { children: ReactNode }) {
  const [lang, setLangState] = useState<Language>('de');
  const [hydrated, setHydrated] = useState(false);

  useEffect(() => {
    setLangState(detectInitialLang());
    setHydrated(true);
  }, []);

  useEffect(() => {
    if (!hydrated) return;
    window.localStorage.setItem(STORAGE_KEY, lang);
    document.documentElement.lang = lang;
  }, [lang, hydrated]);

  const value = useMemo<I18nContextType>(
    () => ({
      lang,
      setLang: (next: Language) => setLangState(next),
      t: (key: TranslationKey) => {
        const dict = translations[lang];
        const value = dict[key];
        if (typeof value === 'string') return value;
        const fallback = translations.de[key];
        return typeof fallback === 'string' ? fallback : String(key);
      },
    }),
    [lang]
  );

  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 I18nProvider');
  return context;
}

export type { TranslationKey };