// ===========================
// Dark Mode Toggle
// ===========================

// Sofort beim Laden: Dark Mode Preference wiederherstellen
(function() {
  if (localStorage.getItem('darkMode') === 'true') {
    document.documentElement.classList.add('dark');
    document.body.classList.add('dark');
  }
})();

// Nach DOM Load: Event Listener attachen
document.addEventListener('DOMContentLoaded', function() {
  const darkModeToggle = document.getElementById('dark-mode-toggle');
  
  if (darkModeToggle) {
    const icon = darkModeToggle.querySelector('.dark-mode-icon');
    
    // Icon auf aktuellen Status setzen
    const isDarkMode = localStorage.getItem('darkMode') === 'true';
    icon.textContent = isDarkMode ? '☀️' : '🌙';
    
    // Click-Handler
    darkModeToggle.addEventListener('click', function(e) {
      e.preventDefault();
      e.stopPropagation();
      
      // Toggle Dark Mode
      document.body.classList.toggle('dark');
      document.documentElement.classList.toggle('dark');
      
      // Speichern in localStorage
      const darkModeState = document.body.classList.contains('dark');
      localStorage.setItem('darkMode', darkModeState ? 'true' : 'false');
      
      // Icon aktualisieren
      icon.textContent = darkModeState ? '☀️' : '🌙';
    });
  }

  // ===========================
  // Hamburger Navigation
  // ===========================
  const navToggle = document.getElementById('nav-toggle');
  const mainNav = document.getElementById('main-nav');

  if (navToggle && mainNav) {
    navToggle.addEventListener('click', function(e) {
      e.stopPropagation();
      const isOpen = mainNav.classList.toggle('open');
      navToggle.classList.toggle('open', isOpen);
      navToggle.setAttribute('aria-expanded', String(isOpen));
    });

    // Menü schließen wenn ein Link geklickt wird
    mainNav.querySelectorAll('a').forEach(function(link) {
      link.addEventListener('click', function() {
        mainNav.classList.remove('open');
        navToggle.classList.remove('open');
        navToggle.setAttribute('aria-expanded', 'false');
      });
    });

    // Menü schließen bei Klick außerhalb
    document.addEventListener('click', function(e) {
      if (!navToggle.contains(e.target) && !mainNav.contains(e.target)) {
        mainNav.classList.remove('open');
        navToggle.classList.remove('open');
        navToggle.setAttribute('aria-expanded', 'false');
      }
    });
  }

  // ===========================
  // Active Navigation Highlighting
  // ===========================
  // Highlight active navigation link
  const currentLocation = location.pathname.split('/').pop() || 'index.html';
  const navLinks = document.querySelectorAll('nav a');
  
  navLinks.forEach(link => {
    const href = link.getAttribute('href');
    if (href === currentLocation) {
      link.classList.add('active');
    } else {
      link.classList.remove('active');
    }
  });

  // Initialize lightbox gallery
  initializeLightbox();

  // Initialize contact form
  initializeContactForm();
});

// ===========================
// Lightbox Gallery
// ===========================

function initializeLightbox() {
  const galleryImages = document.querySelectorAll('.galerie img');
  
  galleryImages.forEach(img => {
    img.addEventListener('click', function() {
      openLightbox(this.src);
    });
  });
}

function openLightbox(imageSrc) {
  // Create overlay
  const overlay = document.createElement('div');
  overlay.className = 'lightbox-overlay';
  
  // Create image container
  const imgContainer = document.createElement('div');
  imgContainer.style.position = 'relative';
  
  // Create close button
  const closeBtn = document.createElement('span');
  closeBtn.className = 'lightbox-close';
  closeBtn.innerHTML = '×';
  closeBtn.addEventListener('click', function(e) {
    e.stopPropagation();
    overlay.remove();
  });
  
  // Create large image
  const img = document.createElement('img');
  img.src = imageSrc;
  
  imgContainer.appendChild(closeBtn);
  imgContainer.appendChild(img);
  overlay.appendChild(imgContainer);
  
  // Close on overlay click
  overlay.addEventListener('click', function() {
    overlay.remove();
  });
  
  // Close on Escape key
  document.addEventListener('keydown', function(e) {
    if (e.key === 'Escape') {
      overlay.remove();
    }
  });
  
  document.body.appendChild(overlay);
}

// ===========================
// Contact Form Handling
// ===========================

function initializeContactForm() {
  const form = document.getElementById('contactForm');
  if (!form) return;

  // Live-Validierung: Fehler beim Verlassen des Feldes clearen
  ['name', 'email', 'subject', 'message'].forEach(function(id) {
    const field = document.getElementById(id);
    if (field) {
      field.addEventListener('input', function() {
        clearFieldError(id);
      });
    }
  });

  form.addEventListener('submit', function(e) {
    e.preventDefault();

    const name    = document.getElementById('name').value.trim();
    const email   = document.getElementById('email').value.trim();
    const subject = document.getElementById('subject').value.trim();
    const message = document.getElementById('message').value.trim();

    let valid = true;

    // Name prüfen
    if (!name) {
      showFieldError('name', 'Bitte gib deinen Namen ein.');
      valid = false;
    } else {
      clearFieldError('name');
    }

    // E-Mail prüfen
    if (!email) {
      showFieldError('email', 'Bitte gib deine E-Mail-Adresse ein.');
      valid = false;
    } else if (!/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email)) {
      showFieldError('email', 'Die E-Mail-Adresse muss ein @ enthalten und gültig sein.');
      valid = false;
    } else {
      clearFieldError('email');
    }

    // Betreff prüfen
    if (!subject) {
      showFieldError('subject', 'Bitte gib einen Betreff ein.');
      valid = false;
    } else {
      clearFieldError('subject');
    }

    // Nachricht prüfen
    if (!message) {
      showFieldError('message', 'Bitte schreib uns eine Nachricht.');
      valid = false;
    } else if (message.length < 10) {
      showFieldError('message', 'Die Nachricht sollte mindestens 10 Zeichen lang sein.');
      valid = false;
    } else {
      clearFieldError('message');
    }

    if (!valid) return;

    // Erfolg
    form.reset();
    ['name', 'email', 'subject', 'message'].forEach(clearFieldError);

    const formMessage = document.getElementById('formMessage');
    if (formMessage) {
      formMessage.innerHTML =
        '<div class="form-success">' +
          '<span class="form-success-icon">✅</span>' +
          '<div>' +
            '<strong>Danke für deine Nachricht!</strong><br>' +
            'Wir melden uns bald bei dir. 💕' +
          '</div>' +
        '</div>';
      formMessage.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
    }
  });
}

function showFieldError(fieldId, message) {
  const field = document.getElementById(fieldId);
  const errorEl = document.getElementById('error-' + fieldId);
  if (field) field.classList.add('input-error');
  if (errorEl) errorEl.textContent = message;
}

function clearFieldError(fieldId) {
  const field = document.getElementById(fieldId);
  const errorEl = document.getElementById('error-' + fieldId);
  if (field) field.classList.remove('input-error');
  if (errorEl) errorEl.textContent = '';
}

function showFormMessage(message, type) {
  const formMessage = document.getElementById('formMessage');
  if (!formMessage) return;
  formMessage.textContent = message;
}

// ===========================
// Smooth Scroll (Progressive Enhancement)
// ===========================

document.addEventListener('click', function(e) {
  if (e.target.tagName === 'A' && e.target.getAttribute('href').startsWith('#')) {
    e.preventDefault();
    const targetId = e.target.getAttribute('href').substring(1);
    const targetElement = document.getElementById(targetId);
    
    if (targetElement) {
      targetElement.scrollIntoView({ behavior: 'smooth' });
    }
  }
});

// ===========================
// Utility: Log
// ===========================

console.log('✅ EIS Website erfolgreich geladen!');
console.log('📚 Veranstaltung: Entwicklung interaktiver Softwareanwendungen');
console.log('🏫 Institution: PH Weingarten');
console.log('👨‍🏫 Dozenten: Stefan Franke und Prof. Dr. Wolfgang Müller');