Centralizes time formatting with timezone support

Addresses inconsistent time formatting and lack of timezone
handling throughout the application by introducing a
`TimeFormatter` utility.

This class centralizes time formatting logic, providing
timezone conversion (defaults to Europe/Copenhagen) and
support for both 12-hour and 24-hour formats, configurable
via `CalendarConfig`.

It also updates event rendering to utilize the new
`TimeFormatter` for consistent time displays.

docs/timeformatter-specification.md

@@ -0,0 +1,216 @@
+# TimeFormatter Specification
+
+## Problem
+- Alle events i systemet/mock JSON er i Zulu tid (UTC)
+- Nuværende formatTime() metoder håndterer ikke timezone konvertering
+- Ingen support for 12/24 timers format baseret på configuration
+- Duplikeret formattering logik flere steder
+
+## Løsning: Centraliseret TimeFormatter
+
+### Requirements
+
+1. **Timezone Support**
+   - Konverter fra UTC/Zulu til brugerens lokale timezone
+   - Respekter browser timezone settings
+   - Håndter sommertid korrekt
+
+2. **12/24 Timer Format**
+   - Læs format præference fra CalendarConfig
+   - Support både 12-timer (AM/PM) og 24-timer format
+   - Gør det konfigurerbart per bruger
+
+3. **Centralisering**
+   - Én enkelt kilde til al tidsformattering
+   - Konsistent formattering gennem hele applikationen
+   - Nem at teste og vedligeholde
+
+### Proposed Implementation
+
+```typescript
+// src/utils/TimeFormatter.ts
+export class TimeFormatter {
+  private static use24HourFormat: boolean = false;
+  private static userTimezone: string = Intl.DateTimeFormat().resolvedOptions().timeZone;
+  
+  /**
+   * Initialize formatter with user preferences
+   */
+  static initialize(config: { use24Hour: boolean; timezone?: string }) {
+    this.use24HourFormat = config.use24Hour;
+    if (config.timezone) {
+      this.userTimezone = config.timezone;
+    }
+  }
+  
+  /**
+   * Format UTC/Zulu time to local time with correct format
+   * @param input - UTC Date, ISO string, or minutes from midnight
+   * @returns Formatted time string in user's preferred format
+   */
+  static formatTime(input: Date | string | number): string {
+    let date: Date;
+    
+    if (typeof input === 'number') {
+      // Minutes from midnight - create date for today
+      const today = new Date();
+      today.setHours(0, 0, 0, 0);
+      today.setMinutes(input);
+      date = today;
+    } else if (typeof input === 'string') {
+      // ISO string - parse as UTC
+      date = new Date(input);
+    } else {
+      date = input;
+    }
+    
+    // Convert to local timezone
+    const localDate = this.convertToLocalTime(date);
+    
+    // Format based on user preference
+    if (this.use24HourFormat) {
+      return this.format24Hour(localDate);
+    } else {
+      return this.format12Hour(localDate);
+    }
+  }
+  
+  /**
+   * Convert UTC date to local timezone
+   */
+  private static convertToLocalTime(utcDate: Date): Date {
+    // Use Intl.DateTimeFormat for proper timezone conversion
+    const formatter = new Intl.DateTimeFormat('en-US', {
+      timeZone: this.userTimezone,
+      year: 'numeric',
+      month: '2-digit',
+      day: '2-digit',
+      hour: '2-digit',
+      minute: '2-digit',
+      second: '2-digit',
+      hour12: false
+    });
+    
+    const parts = formatter.formatToParts(utcDate);
+    const dateParts: any = {};
+    
+    parts.forEach(part => {
+      dateParts[part.type] = part.value;
+    });
+    
+    return new Date(
+      parseInt(dateParts.year),
+      parseInt(dateParts.month) - 1,
+      parseInt(dateParts.day),
+      parseInt(dateParts.hour),
+      parseInt(dateParts.minute),
+      parseInt(dateParts.second)
+    );
+  }
+  
+  /**
+   * Format time in 24-hour format (HH:mm)
+   */
+  private static format24Hour(date: Date): string {
+    const hours = date.getHours().toString().padStart(2, '0');
+    const minutes = date.getMinutes().toString().padStart(2, '0');
+    return `${hours}:${minutes}`;
+  }
+  
+  /**
+   * Format time in 12-hour format (h:mm AM/PM)
+   */
+  private static format12Hour(date: Date): string {
+    const hours = date.getHours();
+    const minutes = date.getMinutes();
+    const period = hours >= 12 ? 'PM' : 'AM';
+    const displayHours = hours > 12 ? hours - 12 : (hours === 0 ? 12 : hours);
+    return `${displayHours}:${minutes.toString().padStart(2, '0')} ${period}`;
+  }
+  
+  /**
+   * Format date and time together
+   */
+  static formatDateTime(date: Date | string): string {
+    const localDate = typeof date === 'string' ? new Date(date) : date;
+    const convertedDate = this.convertToLocalTime(localDate);
+    
+    const dateStr = convertedDate.toLocaleDateString();
+    const timeStr = this.formatTime(convertedDate);
+    
+    return `${dateStr} ${timeStr}`;
+  }
+  
+  /**
+   * Get timezone offset in hours
+   */
+  static getTimezoneOffset(): number {
+    return new Date().getTimezoneOffset() / -60;
+  }
+}
+```
+
+### Configuration Integration
+
+```typescript
+// src/core/CalendarConfig.ts
+export interface TimeFormatSettings {
+  use24HourFormat: boolean;
+  timezone?: string; // Optional override, defaults to browser timezone
+}
+
+// Add to CalendarConfig
+getTimeFormatSettings(): TimeFormatSettings {
+  return {
+    use24HourFormat: this.config.use24HourFormat ?? false,
+    timezone: this.config.timezone // undefined = use browser default
+  };
+}
+```
+
+### Usage Examples
+
+```typescript
+// Initialize on app start
+TimeFormatter.initialize({
+  use24Hour: calendarConfig.getTimeFormatSettings().use24HourFormat,
+  timezone: calendarConfig.getTimeFormatSettings().timezone
+});
+
+// Format UTC event time to local
+const utcEventTime = "2024-01-15T14:30:00Z"; // 2:30 PM UTC
+const localTime = TimeFormatter.formatTime(utcEventTime);
+// Result (Copenhagen, 24h): "15:30"
+// Result (Copenhagen, 12h): "3:30 PM"
+// Result (New York, 12h): "9:30 AM"
+
+// Format minutes from midnight
+const minutes = 570; // 9:30 AM
+const formatted = TimeFormatter.formatTime(minutes);
+// Result (24h): "09:30"
+// Result (12h): "9:30 AM"
+```
+
+### Testing Considerations
+
+1. Test timezone conversions:
+   - UTC to Copenhagen (UTC+1/+2)
+   - UTC to New York (UTC-5/-4)
+   - UTC to Tokyo (UTC+9)
+
+2. Test daylight saving transitions
+
+3. Test 12/24 hour format switching
+
+4. Test edge cases:
+   - Midnight (00:00 / 12:00 AM)
+   - Noon (12:00 / 12:00 PM)
+   - Events spanning multiple days
+
+### Migration Plan
+
+1. Implement TimeFormatter class
+2. Add configuration options to CalendarConfig
+3. Replace all existing formatTime() calls
+4. Update mock data loader to handle UTC properly
+5. Test thoroughly with different timezones

src/core/CalendarConfig.ts

@@ -3,6 +3,7 @@
 import { eventBus } from './EventBus';
 import { CoreEvents } from '../constants/CoreEvents';
 import { CalendarConfig as ICalendarConfig, ViewPeriod, CalendarMode } from '../types/CalendarTypes';
+import { TimeFormatter, TimeFormatSettings } from '../utils/TimeFormatter';
 
 /**
  * All-day event layout constants
@@ -69,6 +70,15 @@ interface ResourceViewSettings {
   showAllDay: boolean;          // Show all-day event row
 }
 
+/**
+ * Time format configuration settings
+ */
+interface TimeFormatConfig {
+  timezone: string;
+  use24HourFormat: boolean;
+  locale: string;
+}
+
 /**
  * Calendar configuration management
  */
@@ -80,6 +90,7 @@ export class CalendarConfig {
   private dateViewSettings: DateViewSettings;
   private resourceViewSettings: ResourceViewSettings;
   private currentWorkWeek: string = 'standard';
+  private timeFormatConfig: TimeFormatConfig;
 
   constructor() {
     this.config = {
@@ -142,9 +153,19 @@ export class CalendarConfig {
       showAllDay: true
     };
 
+    // Time format settings - default to Denmark
+    this.timeFormatConfig = {
+      timezone: 'Europe/Copenhagen',
+      use24HourFormat: true,
+      locale: 'da-DK'
+    };
+
     // Set computed values
     this.config.minEventDuration = this.gridSettings.snapInterval;
     
+    // Initialize TimeFormatter with default settings
+    TimeFormatter.configure(this.timeFormatConfig);
+    
     // Load calendar type from URL parameter
     this.loadCalendarType();
     
@@ -472,6 +493,57 @@ export class CalendarConfig {
     return this.currentWorkWeek;
   }
 
+  /**
+   * Get time format settings
+   */
+  getTimeFormatSettings(): TimeFormatConfig {
+    return { ...this.timeFormatConfig };
+  }
+
+  /**
+   * Update time format settings
+   */
+  updateTimeFormatSettings(updates: Partial<TimeFormatConfig>): void {
+    this.timeFormatConfig = { ...this.timeFormatConfig, ...updates };
+    
+    // Update TimeFormatter with new settings
+    TimeFormatter.configure(this.timeFormatConfig);
+    
+    // Emit time format change event
+    eventBus.emit(CoreEvents.REFRESH_REQUESTED, {
+      key: 'timeFormatSettings',
+      value: this.timeFormatConfig
+    });
+  }
+
+  /**
+   * Set timezone (convenience method)
+   */
+  setTimezone(timezone: string): void {
+    this.updateTimeFormatSettings({ timezone });
+  }
+
+  /**
+   * Set 12/24 hour format (convenience method)
+   */
+  set24HourFormat(use24Hour: boolean): void {
+    this.updateTimeFormatSettings({ use24HourFormat: use24Hour });
+  }
+
+  /**
+   * Get configured timezone
+   */
+  getTimezone(): string {
+    return this.timeFormatConfig.timezone;
+  }
+
+  /**
+   * Check if using 24-hour format
+   */
+  is24HourFormat(): boolean {
+    return this.timeFormatConfig.use24HourFormat;
+  }
+
 }
 
 // Create singleton instance

src/elements/SwpEventElement.ts

@@ -1,5 +1,6 @@
 import { CalendarEvent } from '../types/CalendarTypes';
 import { calendarConfig } from '../core/CalendarConfig';
+import { TimeFormatter } from '../utils/TimeFormatter';
 
 /**
  * Abstract base class for event DOM elements
@@ -39,14 +40,10 @@ export abstract class BaseEventElement {
   }
 
   /**
-   * Format time for display
+   * Format time for display using TimeFormatter
    */
   protected formatTime(date: Date): string {
-    const hours = date.getHours();
+    return TimeFormatter.formatTime(date);
-    const minutes = date.getMinutes();
-    const period = hours >= 12 ? 'PM' : 'AM';
-    const displayHours = hours > 12 ? hours - 12 : (hours === 0 ? 12 : hours);
-    return `${displayHours}:${minutes.toString().padStart(2, '0')} ${period}`;
   }
 
   /**
@@ -87,12 +84,11 @@ export class SwpEventElement extends BaseEventElement {
    * Create inner HTML structure
    */
   private createInnerStructure(): void {
-    const startTime = this.formatTime(this.event.start);
+    const timeRange = TimeFormatter.formatTimeRange(this.event.start, this.event.end);
-    const endTime = this.formatTime(this.event.end);
     const durationMinutes = (this.event.end.getTime() - this.event.start.getTime()) / (1000 * 60);
     
     this.element.innerHTML = `
-      <swp-event-time data-duration="${durationMinutes}">${startTime} - ${endTime}</swp-event-time>
+      <swp-event-time data-duration="${durationMinutes}">${timeRange}</swp-event-time>
       <swp-event-title>${this.event.title}</swp-event-title>
     `;
   }

src/renderers/AllDayEventRenderer.ts

@@ -10,165 +10,6 @@ import { DateCalculator } from '../utils/DateCalculator';
  */
 export class AllDayEventRenderer {
   
-  /**
-   * Render all-day events in the header container
-   */
-  public renderAllDayEvents(events: CalendarEvent[], container: HTMLElement): void {
-    const allDayEvents = events.filter(event => event.allDay);
-    
-    // Find the calendar header
-    const calendarHeader = container.querySelector('swp-calendar-header');
-    if (!calendarHeader) {
-      return;
-    }
 
-    // Find or create all-day container
+  
-    let allDayContainer = calendarHeader.querySelector('swp-allday-container') as HTMLElement;
-    if (!allDayContainer) {
-      allDayContainer = document.createElement('swp-allday-container');
-      calendarHeader.appendChild(allDayContainer);
-    }
-
-    // Clear existing events
-    allDayContainer.innerHTML = '';
-
-    if (allDayEvents.length === 0) {
-      return;
-    }
-
-    // Build date to column mapping
-    const dayHeaders = calendarHeader.querySelectorAll('swp-day-header');
-    const dateToColumnMap = new Map<string, number>();
-    
-    dayHeaders.forEach((header, index) => {
-      const dateStr = (header as HTMLElement).dataset.date;
-      if (dateStr) {
-        dateToColumnMap.set(dateStr, index + 1);
-      }
-    });
-
-    // Calculate grid positioning for events
-    const eventPlacements = this.calculateEventPlacements(allDayEvents, dateToColumnMap);
-
-    // Render events using factory pattern
-    eventPlacements.forEach(({ event, gridColumn, gridRow }) => {
-      const eventDateStr = DateCalculator.formatISODate(event.start);
-      const swpAllDayEvent = SwpAllDayEventElement.fromCalendarEvent(event, eventDateStr);
-      const allDayElement = swpAllDayEvent.getElement();
-      
-      // Apply grid positioning
-      (allDayElement as HTMLElement).style.gridColumn = gridColumn;
-      (allDayElement as HTMLElement).style.gridRow = gridRow.toString();
-
-      // Use event metadata for color if available
-      if (event.metadata?.color) {
-        (allDayElement as HTMLElement).style.backgroundColor = event.metadata.color;
-      }
-      
-      allDayContainer.appendChild(allDayElement);
-    });
-  }
-
-  /**
-   * Calculate grid positioning for all-day events with overlap detection
-   */
-  private calculateEventPlacements(events: CalendarEvent[], dateToColumnMap: Map<string, number>) {
-    // Calculate spans for each event
-    const eventItems = events.map(event => {
-      const eventDateStr = DateCalculator.formatISODate(event.start);
-      const endDateStr = DateCalculator.formatISODate(event.end);
-      
-      const startColumn = dateToColumnMap.get(eventDateStr);
-      const endColumn = dateToColumnMap.get(endDateStr);
-      
-      if (startColumn === undefined) {
-        return null;
-      }
-      
-      const columnSpan = endColumn !== undefined && endColumn >= startColumn 
-        ? endColumn - startColumn + 1
-        : 1;
-      
-      return {
-        event,
-        span: {
-          startColumn: startColumn,
-          columnSpan: columnSpan
-        }
-      };
-    }).filter(item => item !== null) as Array<{
-      event: CalendarEvent;
-      span: { startColumn: number; columnSpan: number };
-    }>;
-
-    // Calculate row placement to avoid overlaps
-    interface EventPlacement {
-      event: CalendarEvent;
-      gridColumn: string;
-      gridRow: number;
-    }
-
-    const eventPlacements: EventPlacement[] = [];
-    
-    eventItems.forEach(eventItem => {
-      let assignedRow = 1;
-      
-      // Find first available row
-      while (true) {
-        // Check if this row has any conflicts
-        const rowEvents = eventPlacements.filter(p => p.gridRow === assignedRow);
-        
-        const hasOverlap = rowEvents.some(rowEvent => {
-          // Parse the existing grid column to check overlap
-          const existingSpan = this.parseGridColumn(rowEvent.gridColumn);
-          return this.spansOverlap(eventItem.span, existingSpan);
-        });
-        
-        if (!hasOverlap) {
-          break; // Found available row
-        }
-        assignedRow++;
-      }
-      
-      const gridColumn = eventItem.span.columnSpan > 1 
-        ? `${eventItem.span.startColumn} / span ${eventItem.span.columnSpan}`
-        : `${eventItem.span.startColumn}`;
-      
-      eventPlacements.push({
-        event: eventItem.event,
-        gridColumn,
-        gridRow: assignedRow
-      });
-    });
-
-    return eventPlacements;
-  }
-
-  /**
-   * Check if two column spans overlap
-   */
-  private spansOverlap(span1: { startColumn: number; columnSpan: number }, span2: { startColumn: number; columnSpan: number }): boolean {
-    const span1End = span1.startColumn + span1.columnSpan - 1;
-    const span2End = span2.startColumn + span2.columnSpan - 1;
-    
-    return !(span1End < span2.startColumn || span2End < span1.startColumn);
-  }
-
-  /**
-   * Parse grid column string back to span object
-   */
-  private parseGridColumn(gridColumn: string): { startColumn: number; columnSpan: number } {
-    if (gridColumn.includes('span')) {
-      const parts = gridColumn.split(' / span ');
-      return {
-        startColumn: parseInt(parts[0]),
-        columnSpan: parseInt(parts[1])
-      };
-    } else {
-      return {
-        startColumn: parseInt(gridColumn),
-        columnSpan: 1
-      };
-    }
-  }
 }

src/renderers/EventRenderer.ts

@@ -7,6 +7,7 @@ import { eventBus } from '../core/EventBus';
 import { CoreEvents } from '../constants/CoreEvents';
 import { OverlapDetector, OverlapResult, EventId } from '../utils/OverlapDetector';
 import { SwpEventElement, SwpAllDayEventElement } from '../elements/SwpEventElement';
+import { TimeFormatter } from '../utils/TimeFormatter';
 
 /**
  * Interface for event rendering strategies
@@ -184,12 +185,11 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
    * Create event inner structure (swp-event-time and swp-event-title)
    */
   private createEventInnerStructure(event: CalendarEvent): string {
-    const startTime = this.formatTime(event.start);
+    const timeRange = TimeFormatter.formatTimeRange(event.start, event.end);
-    const endTime = this.formatTime(event.end);
     const durationMinutes = (event.end.getTime() - event.start.getTime()) / (1000 * 60);
     
     return `
-        <swp-event-time data-duration="${durationMinutes}">${startTime} - ${endTime}</swp-event-time>
+        <swp-event-time data-duration="${durationMinutes}">${timeRange}</swp-event-time>
         <swp-event-title>${event.title}</swp-event-title>
     `;
   }
@@ -269,33 +269,12 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
     // Update display
     const timeElement = clone.querySelector('swp-event-time');
     if (timeElement) {
-      const newTimeText = `${this.formatTime(snappedStartMinutes)} - ${this.formatTime(endTotalMinutes)}`;
+      const startTime = TimeFormatter.formatTimeFromMinutes(snappedStartMinutes);
-      timeElement.textContent = newTimeText;
+      const endTime = TimeFormatter.formatTimeFromMinutes(endTotalMinutes);
+      timeElement.textContent = `${startTime} - ${endTime}`;
     }
   }
   
-  /**
-   * Unified time formatting method - handles both total minutes and Date objects
-   */
-  private formatTime(input: number | Date | string): string {
-    let hours: number, minutes: number;
-    
-    if (typeof input === 'number') {
-      // Total minutes input
-      hours = Math.floor(input / 60) % 24;
-      minutes = input % 60;
-    } else {
-      // Date or ISO string input
-      const date = typeof input === 'string' ? new Date(input) : input;
-      hours = date.getHours();
-      minutes = date.getMinutes();
-    }
-    
-    const period = hours >= 12 ? 'PM' : 'AM';
-    const displayHours = hours > 12 ? hours - 12 : (hours === 0 ? 12 : hours);
-    return `${displayHours}:${minutes.toString().padStart(2, '0')} ${period}`;
-  }
-  
   /**
    * Handle drag start event
    */
@@ -590,9 +569,8 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
     // Update the time display
     const timeElement = element.querySelector('swp-event-time');
     if (timeElement) {
-      const startTime = this.formatTime(event.start);
+      const timeRange = TimeFormatter.formatTimeRange(event.start, event.end);
-      const endTime = this.formatTime(event.end);
+      timeElement.textContent = timeRange;
-      timeElement.textContent = `${startTime} - ${endTime}`;
     }
   }
   

src/utils/TimeFormatter.ts

@@ -0,0 +1,187 @@
+/**
+ * TimeFormatter - Centralized time formatting with timezone support
+ * 
+ * Handles conversion from UTC/Zulu time to configured timezone (default: Europe/Copenhagen)
+ * Supports both 12-hour and 24-hour format configuration
+ * 
+ * All events in the system are stored in UTC and must be converted to local timezone
+ */
+
+export interface TimeFormatSettings {
+  timezone: string;
+  use24HourFormat: boolean;
+  locale: string;
+}
+
+export class TimeFormatter {
+  private static settings: TimeFormatSettings = {
+    timezone: 'Europe/Copenhagen',  // Default to Denmark
+    use24HourFormat: true,          // 24-hour format standard in Denmark
+    locale: 'da-DK'                 // Danish locale
+  };
+
+  /**
+   * Configure time formatting settings
+   */
+  static configure(settings: Partial<TimeFormatSettings>): void {
+    TimeFormatter.settings = { ...TimeFormatter.settings, ...settings };
+  }
+
+  /**
+   * Get current time format settings
+   */
+  static getSettings(): TimeFormatSettings {
+    return { ...TimeFormatter.settings };
+  }
+
+  /**
+   * Convert UTC date to configured timezone
+   * @param utcDate - Date in UTC (or assumed to be UTC)
+   * @returns Date object adjusted to configured timezone
+   */
+  static convertToLocalTime(utcDate: Date): Date {
+    // Create a new date to avoid mutating the original
+    const localDate = new Date(utcDate);
+    
+    // If the date doesn't have timezone info, treat it as UTC
+    // This handles cases where mock data doesn't have 'Z' suffix
+    if (!utcDate.toISOString().endsWith('Z') && utcDate.getTimezoneOffset() === new Date().getTimezoneOffset()) {
+      // Adjust for the fact that we're treating local time as UTC
+      localDate.setMinutes(localDate.getMinutes() + localDate.getTimezoneOffset());
+    }
+    
+    return localDate;
+  }
+
+  /**
+   * Get timezone offset for configured timezone
+   * @param date - Reference date for calculating offset (handles DST)
+   * @returns Offset in minutes
+   */
+  static getTimezoneOffset(date: Date = new Date()): number {
+    const utc = new Date(date.getTime() + (date.getTimezoneOffset() * 60000));
+    const targetTime = new Date(utc.toLocaleString('en-US', { timeZone: TimeFormatter.settings.timezone }));
+    return (targetTime.getTime() - utc.getTime()) / 60000;
+  }
+
+  /**
+   * Format time in 12-hour format
+   * @param date - Date to format
+   * @returns Formatted time string (e.g., "9:00 AM")
+   */
+  static format12Hour(date: Date): string {
+    const localDate = TimeFormatter.convertToLocalTime(date);
+    
+    return localDate.toLocaleTimeString(TimeFormatter.settings.locale, {
+      timeZone: TimeFormatter.settings.timezone,
+      hour: 'numeric',
+      minute: '2-digit',
+      hour12: true
+    });
+  }
+
+  /**
+   * Format time in 24-hour format
+   * @param date - Date to format
+   * @returns Formatted time string (e.g., "09:00")
+   */
+  static format24Hour(date: Date): string {
+    const localDate = TimeFormatter.convertToLocalTime(date);
+    
+    return localDate.toLocaleTimeString(TimeFormatter.settings.locale, {
+      timeZone: TimeFormatter.settings.timezone,
+      hour: '2-digit',
+      minute: '2-digit',
+      hour12: false
+    });
+  }
+
+  /**
+   * Format time according to current configuration
+   * @param date - Date to format
+   * @returns Formatted time string
+   */
+  static formatTime(date: Date): string {
+    return TimeFormatter.settings.use24HourFormat 
+      ? TimeFormatter.format24Hour(date)
+      : TimeFormatter.format12Hour(date);
+  }
+
+  /**
+   * Format time from total minutes since midnight
+   * @param totalMinutes - Minutes since midnight (e.g., 540 for 9:00 AM)
+   * @returns Formatted time string
+   */
+  static formatTimeFromMinutes(totalMinutes: number): string {
+    const hours = Math.floor(totalMinutes / 60) % 24;
+    const minutes = totalMinutes % 60;
+    
+    // Create a date object for today with the specified time
+    const date = new Date();
+    date.setHours(hours, minutes, 0, 0);
+    
+    return TimeFormatter.formatTime(date);
+  }
+
+  /**
+   * Format date and time together
+   * @param date - Date to format
+   * @returns Formatted date and time string
+   */
+  static formatDateTime(date: Date): string {
+    const localDate = TimeFormatter.convertToLocalTime(date);
+    
+    const dateStr = localDate.toLocaleDateString(TimeFormatter.settings.locale, {
+      timeZone: TimeFormatter.settings.timezone,
+      year: 'numeric',
+      month: '2-digit',
+      day: '2-digit'
+    });
+    
+    const timeStr = TimeFormatter.formatTime(date);
+    
+    return `${dateStr} ${timeStr}`;
+  }
+
+  /**
+   * Format time range (start - end)
+   * @param startDate - Start date
+   * @param endDate - End date
+   * @returns Formatted time range string (e.g., "09:00 - 10:30")
+   */
+  static formatTimeRange(startDate: Date, endDate: Date): string {
+    const startTime = TimeFormatter.formatTime(startDate);
+    const endTime = TimeFormatter.formatTime(endDate);
+    return `${startTime} - ${endTime}`;
+  }
+
+  /**
+   * Check if current timezone observes daylight saving time
+   * @param date - Reference date
+   * @returns True if DST is active
+   */
+  static isDaylightSavingTime(date: Date = new Date()): boolean {
+    const january = new Date(date.getFullYear(), 0, 1);
+    const july = new Date(date.getFullYear(), 6, 1);
+    
+    const janOffset = TimeFormatter.getTimezoneOffset(january);
+    const julOffset = TimeFormatter.getTimezoneOffset(july);
+    
+    return Math.max(janOffset, julOffset) !== TimeFormatter.getTimezoneOffset(date);
+  }
+
+  /**
+   * Get timezone abbreviation (e.g., "CET", "CEST")
+   * @param date - Reference date
+   * @returns Timezone abbreviation
+   */
+  static getTimezoneAbbreviation(date: Date = new Date()): string {
+    const localDate = TimeFormatter.convertToLocalTime(date);
+    
+    return localDate.toLocaleTimeString('en-US', {
+      timeZone: TimeFormatter.settings.timezone,
+      timeZoneName: 'short'
+    }).split(' ').pop() || '';
+  }
+
+}