/**
 * API Functions
 * Backend communication layer
 */

/**
 * Fetch entries from backend
 */
async function fetchEntries(fromDate = null, toDate = null) {
  try {
    let url = '/api/entries';
    const params = new URLSearchParams();
    
    if (fromDate) params.append('from', fromDate);
    if (toDate) params.append('to', toDate);
    
    if (params.toString()) {
      url += '?' + params.toString();
    }
    
    const response = await fetch(url);
    
    if (!response.ok) {
      throw new Error('Failed to fetch entries');
    }
    
    const entries = await response.json();
    return entries;
  } catch (error) {
    console.error('Error fetching entries:', error);
    showNotification('Fehler beim Laden der Einträge', 'error');
    return [];
  }
}

/**
 * Create a new entry
 */
async function createEntry(date, startTime, endTime, pauseMinutes, location) {
  try {
    const body = {
      date: formatDateISO(date),
      startTime,
      endTime,
      location: location || 'office'
    };
    
    // Only include pauseMinutes if explicitly provided (not empty)
    if (pauseMinutes !== null && pauseMinutes !== undefined && pauseMinutes !== '') {
      body.pauseMinutes = parseInt(pauseMinutes);
    }
    
    const response = await fetch('/api/entries', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json'
      },
      body: JSON.stringify(body)
    });
    
    if (!response.ok) {
      const error = await response.json();
      throw new Error(error.error || 'Failed to create entry');
    }
    
    const entry = await response.json();
    return entry;
  } catch (error) {
    console.error('Error creating entry:', error);
    showNotification(error.message || 'Fehler beim Erstellen des Eintrags', 'error');
    return null;
  }
}

/**
 * Update an existing entry
 */
async function updateEntry(id, date, startTime, endTime, pauseMinutes, location) {
  try {
    const body = {
      date: formatDateISO(date),
      startTime,
      endTime,
      location: location || 'office'
    };
    
    // Only include pauseMinutes if explicitly provided (not empty)
    if (pauseMinutes !== null && pauseMinutes !== undefined && pauseMinutes !== '') {
      body.pauseMinutes = parseInt(pauseMinutes);
    }
    
    const response = await fetch(`/api/entries/${id}`, {
      method: 'PUT',
      headers: {
        'Content-Type': 'application/json'
      },
      body: JSON.stringify(body)
    });
    
    if (!response.ok) {
      const error = await response.json();
      throw new Error(error.error || 'Failed to update entry');
    }
    
    const entry = await response.json();
    return entry;
  } catch (error) {
    console.error('Error updating entry:', error);
    showNotification(error.message || 'Fehler beim Aktualisieren des Eintrags', 'error');
    return null;
  }
}

/**
 * Delete an entry
 */
async function deleteEntry(id) {
  try {
    const response = await fetch(`/api/entries/${id}`, {
      method: 'DELETE'
    });
    
    if (!response.ok) {
      throw new Error('Failed to delete entry');
    }
    
    return true;
  } catch (error) {
    console.error('Error deleting entry:', error);
    showNotification('Fehler beim Löschen des Eintrags', 'error');
    return false;
  }
}

/**
 * Get a setting by key
 */
async function getSetting(key) {
  try {
    const response = await fetch(`/api/settings/${key}`);
    
    if (!response.ok) {
      if (response.status === 404) {
        return null; // Setting doesn't exist yet
      }
      throw new Error('Failed to get setting');
    }
    
    const data = await response.json();
    return data.value;
  } catch (error) {
    console.error('Error getting setting:', error);
    return null;
  }
}

/**
 * Set a setting
 */
async function setSetting(key, value) {
  try {
    const response = await fetch('/api/settings', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({ key, value })
    });
    
    if (!response.ok) {
      throw new Error('Failed to set setting');
    }
    
    return true;
  } catch (error) {
    console.error('Error setting setting:', error);
    showNotification('Fehler beim Speichern der Einstellung', 'error');
    return false;
  }
}