class Icalendar::Values::Recur

def initialize(value, params = {})
  if value.is_a? Icalendar::Values::Recur
    super value.value, params
  else
    super OpenStruct.new(parse_fields value), params
  end
end

def parse_fields(value)
  {
    frequency: (value =~ PARSE_FIELDS_FREQUENCY_REGEX ? $1.upcase : nil),
    until: (value =~ PARSE_FIELDS_UNTIL_REGEX ? $1 : nil),
    count: (value =~ PARSE_FIELDS_COUNT_REGEX ? $1.to_i : nil),
    interval: (value =~ PARSE_FIELDS_INTERVAL_REGEX ? $1.to_i : nil),
    by_second: (value =~ PARSE_FIELDS_BY_SECOND_REGEX ? $1.split(',').map { |i| i.to_i } : nil),
    by_minute: (value =~ PARSE_FIELDS_BY_MINUTE_REGEX ? $1.split(',').map { |i| i.to_i } : nil),
    by_hour: (value =~ PARSE_FIELDS_BY_HOUR_REGEX ? $1.split(',').map { |i| i.to_i } : nil),
    by_day: (value =~ PARSE_FIELDS_BY_DAY_REGEX ? $1.split(',') : nil),
    by_month_day: (value =~ PARSE_FIELDS_BY_MONTH_DAY_REGEX ? $1.split(',') : nil),
    by_year_day: (value =~ PARSE_FIELDS_BY_YEAR_DAY_REGEX ? $1.split(',') : nil),
    by_week_number: (value =~ PARSE_FIELDS_BY_WEEK_NUMBER_REGEX ? $1.split(',') : nil),
    by_month: (value =~ PARSE_FIELDS_BY_MONTH_REGEX ? $1.split(',').map { |i| i.to_i } : nil),
    by_set_position: (value =~ PARSE_FIELDS_BY_SET_POSITON_REGEX ? $1.split(',') : nil),
    week_start: (value =~ PARSE_FIELDS_BY_WEEK_START_REGEX ? $1.upcase : nil)
  }
end

def valid?
  return false if frequency.nil?
  return false if !self.until.nil? && !count.nil?
  true
end

def value_ical
  builder = ["FREQ=#{frequency}"]
  builder << "UNTIL=#{self.until}" unless self.until.nil?
  builder << "COUNT=#{count}" unless count.nil?
  builder << "INTERVAL=#{interval}" unless interval.nil?
  builder << "BYSECOND=#{by_second.join ','}" unless by_second.nil?
  builder << "BYMINUTE=#{by_minute.join ','}" unless by_minute.nil?
  builder << "BYHOUR=#{by_hour.join ','}" unless by_hour.nil?
  builder << "BYDAY=#{by_day.join ','}" unless by_day.nil?
  builder << "BYMONTHDAY=#{by_month_day.join ','}" unless by_month_day.nil?
  builder << "BYYEARDAY=#{by_year_day.join ','}" unless by_year_day.nil?
  builder << "BYWEEKNO=#{by_week_number.join ','}" unless by_week_number.nil?
  builder << "BYMONTH=#{by_month.join ','}" unless by_month.nil?
  builder << "BYSETPOS=#{by_set_position.join ','}" unless by_set_position.nil?
  builder << "WKST=#{week_start}" unless week_start.nil?
  builder.join ';'
end