Date/Time Utilities

var DateTimeUtils = Class.create();
DateTimeUtils.prototype = {

  /**
   * Add business days to a date (excludes weekends and holidays)
   *
   * @param {GlideDateTime} startDate - Starting date
   * @param {number} days - Number of business days to add
   * @param {string} scheduleId - (Optional) sys_id of schedule to use
   * @returns {GlideDateTime} Calculated date
   */
  addBusinessDays: function(startDate, days, scheduleId) {
    if (!startDate || !days) {
      return startDate;
    }

    var schedule;
    if (scheduleId) {
      schedule = new GlideSchedule(scheduleId);
    } else {
      // Use default 8-5 schedule (sys_id for "8-5 weekdays excluding holidays")
      schedule = new GlideSchedule('c6a2389e0a0a0b9b006cfc04227be354');
    }

    var gdt = new GlideDateTime(startDate);
    var duration = new GlideDuration(days * 24 * 60 * 60 * 1000);  // Convert days to ms

    var endDate = schedule.add(gdt, duration);
    return endDate;
  },

  /**
   * Calculate business days between two dates
   *
   * @param {GlideDateTime} startDate - Start date
   * @param {GlideDateTime} endDate - End date
   * @param {string} scheduleId - (Optional) sys_id of schedule to use
   * @returns {number} Number of business days
   */
  getBusinessDaysBetween: function(startDate, endDate, scheduleId) {
    if (!startDate || !endDate) {
      return 0;
    }

    var schedule;
    if (scheduleId) {
      schedule = new GlideSchedule(scheduleId);
    } else {
      schedule = new GlideSchedule('c6a2389e0a0a0b9b006cfc04227be354');
    }

    var duration = schedule.duration(startDate, endDate);
    var days = duration.getDayPart();
    var hours = duration.getHourPart();

    // Convert to decimal days
    var totalDays = days + (hours / 24);
    return totalDays;
  },

  /**
   * Format date to user-friendly string
   *
   * @param {GlideDateTime} dateTime - Date to format
   * @param {string} format - Format type: 'short', 'long', 'time', 'datetime'
   * @returns {string} Formatted date string
   */
  formatDate: function(dateTime, format) {
    if (!dateTime) {
      return '';
    }

    var gdt = new GlideDateTime(dateTime);
    format = format || 'short';

    switch(format) {
      case 'short':
        // MM/DD/YYYY
        return gdt.getDisplayValue().split(' ')[0];

      case 'long':
        // Month DD, YYYY
        return gdt.getByFormat('MMMM dd, yyyy');

      case 'time':
        // HH:MM AM/PM
        return gdt.getByFormat('hh:mm a');

      case 'datetime':
        // MM/DD/YYYY HH:MM AM/PM
        return gdt.getByFormat('MM/dd/yyyy hh:mm a');

      case 'iso':
        // ISO 8601 format
        return gdt.getValue();

      default:
        return gdt.getDisplayValue();
    }
  },

  /**
   * Get relative time description (e.g., "2 hours ago", "in 3 days")
   *
   * @param {GlideDateTime} dateTime - Date to compare
   * @returns {string} Relative time description
   */
  getRelativeTime: function(dateTime) {
    if (!dateTime) {
      return '';
    }

    var now = new GlideDateTime();
    var target = new GlideDateTime(dateTime);

    var diff = gs.dateDiff(now.getValue(), target.getValue(), true);  // in seconds
    var absDiff = Math.abs(diff);

    var isPast = diff > 0;
    var prefix = isPast ? '' : 'in ';
    var suffix = isPast ? ' ago' : '';

    // Calculate time units
    var seconds = absDiff;
    var minutes = Math.floor(seconds / 60);
    var hours = Math.floor(minutes / 60);
    var days = Math.floor(hours / 24);
    var weeks = Math.floor(days / 7);
    var months = Math.floor(days / 30);
    var years = Math.floor(days / 365);

    // Determine appropriate unit
    if (years > 0) {
      return prefix + years + (years === 1 ? ' year' : ' years') + suffix;
    } else if (months > 0) {
      return prefix + months + (months === 1 ? ' month' : ' months') + suffix;
    } else if (weeks > 0) {
      return prefix + weeks + (weeks === 1 ? ' week' : ' weeks') + suffix;
    } else if (days > 0) {
      return prefix + days + (days === 1 ? ' day' : ' days') + suffix;
    } else if (hours > 0) {
      return prefix + hours + (hours === 1 ? ' hour' : ' hours') + suffix;
    } else if (minutes > 0) {
      return prefix + minutes + (minutes === 1 ? ' minute' : ' minutes') + suffix;
    } else {
      return 'just now';
    }
  },

  /**
   * Check if date is within business hours
   *
   * @param {GlideDateTime} dateTime - Date to check
   * @param {string} scheduleId - (Optional) sys_id of schedule to use
   * @returns {boolean} True if within business hours
   */
  isBusinessHours: function(dateTime, scheduleId) {
    if (!dateTime) {
      return false;
    }

    var schedule;
    if (scheduleId) {
      schedule = new GlideSchedule(scheduleId);
    } else {
      schedule = new GlideSchedule('c6a2389e0a0a0b9b006cfc04227be354');
    }

    return schedule.isInSchedule(dateTime);
  },

  /**
   * Get the next business day
   *
   * @param {GlideDateTime} startDate - Starting date (defaults to now)
   * @returns {GlideDateTime} Next business day
   */
  getNextBusinessDay: function(startDate) {
    var gdt = startDate ? new GlideDateTime(startDate) : new GlideDateTime();

    // Add one day at a time until we find a business day
    var maxAttempts = 10;  // Prevent infinite loop
    var attempts = 0;

    do {
      gdt.addDaysLocalTime(1);
      var dayOfWeek = gdt.getDayOfWeekLocalTime();
      attempts++;

      // 1 = Sunday, 7 = Saturday
      if (dayOfWeek !== 1 && dayOfWeek !== 7) {
        return gdt;
      }
    } while (attempts < maxAttempts);

    return gdt;
  },

  type: 'DateTimeUtils'
};