Module: Protocol::Caldav::Ical::Rrule

Defined in:
lib/protocol/caldav/ical/rrule.rb

Constant Summary collapse

DAYS = 
{ 'MO' => 1, 'TU' => 2, 'WE' => 3, 'TH' => 4, 'FR' => 5, 'SA' => 6, 'SU' => 0 }.freeze

Class Method Summary collapse

Class Method Details

.expand(dtstart:, rrule_value:, range_start:, range_end:, exdates: [], max_count: 10000) ⇒ Array<Time>

Expand an RRULE into concrete occurrence start times within a range.

Parameters:

  • dtstart (Time) —

    base event start

  • rrule_value (String) —

    RRULE property value (e.g. "FREQ=DAILY;COUNT=5")

  • range_start (Time) —

    query window start

  • range_end (Time) —

    query window end

  • exdates (Array<Time>) (defaults to: []) —

    excluded dates

  • max_count (Integer) (defaults to: 10000) —

    safety limit to prevent infinite expansion

Returns:

  • (Array<Time>) —

    occurrence start times within range



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# File 'lib/protocol/caldav/ical/rrule.rb', line 22

def expand(dtstart:, rrule_value:, range_start:, range_end:, exdates: [], max_count: 10000)
  parts = parse_rrule(rrule_value)
  freq = parts['FREQ']
  if freq
    interval = (parts['INTERVAL'] || '1').to_i
    count = parts['COUNT']&.to_i
    if parts['UNTIL']
      until_time = parse_dt(parts['UNTIL'])
    else
      until_time = nil
    end
    byday = parts['BYDAY']&.split(',')
    bymonthday = parts['BYMONTHDAY']&.split(',')&.map(&:to_i)
    bymonth = parts['BYMONTH']&.split(',')&.map(&:to_i)
    occurrences = []
    current = dtstart
    generated = 0
    loop do
      # Stop conditions
      if until_time && current > until_time
        break
      end
      if current > range_end
        break
      end
      if count && generated >= count
        break
      end
      if occurrences.length >= max_count
        break
      end

      candidates = expand_freq(
        freq,
        current,
        interval,
        byday,
        bymonthday,
        bymonth,
        dtstart,
      )

      candidates.each do |candidate|
        if until_time && candidate > until_time
          break
        end
        if count && generated >= count
          break
        end
        if occurrences.length >= max_count
          break
        end

        generated += 1

        if candidate < range_start && candidate < dtstart
          next
        end
        if candidate >= range_end
          next
        end
        if exdates.any? { |ex| times_equal?(candidate, ex) }
          next
        end

        if candidate >= range_start
          occurrences << candidate
        end
      end

      current = advance(freq, current, interval)
    end
    occurrences.sort
  else
    [dtstart]
  end
end