Finding the number of users who have had 2 confirmed grouper requests at any one time

users_with_overlapping_requests.rb

require 'date'

class Range
  def intersection(other)
    return nil if (self.max < other.begin or other.max < self.begin) 
    [self.begin, other.begin].max..[self.max, other.max].min
  end
  alias_method :&, :intersection
end

user_requests = Groupers::Request.all.group_by(&:user_id)
user_requests.select do |user_id, requests|
  ranges = requests.map do |r|
    cancelled_at = Crews::Cancellation.where(crew_id: r.crew_id).first.try(:created_at)
    r.created_at..[r.starts_at, cancelled_at, r.failed_at].compact.min
  end
  intersections = ranges.combination(2).select { |r1, r2| (r1 & r2).present? }
  intersections.count > 0 ? true : false
end


111 # without taking cancelled_at/filed_at into consideration
200 # taking cancelled_at into consideration
257 # taking failed_at into consideration