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



24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
 
# File 'lib/protocol/caldav/ical/rrule.rb', line 24

def expand(dtstart:, rrule_value:, range_start:, range_end:, exdates: [], max_count: 10000)
  parts = parse_rrule(rrule_value)
  freq = parts['FREQ']
  return [dtstart] unless freq

  interval = (parts['INTERVAL'] || '1').to_i
  count = parts['COUNT']&.to_i
  until_time = parts['UNTIL'] ? parse_dt(parts['UNTIL']) : nil
  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
    break if until_time && current > until_time
    break if current > range_end
    break if count && generated >= count
    break if occurrences.length >= max_count

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

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

      generated += 1

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

      occurrences << candidate if candidate >= range_start
    end

    current = advance(freq, current, interval)
  end

  occurrences.sort
end