On-call rota with 7 people for 24/7 with 24 hours per rota

oncall.rb

class Rota
  def initialize(members, window)
    @members = members
    @window = window
    @enumerator = buid_enumerator
  end

  def take
    @window.times.map {
      walk
    }
  end

  private

  def walk
    @enumerator.peek
    @enumerator.next
  end

  def buid_enumerator
    Enumerator.new {|y|
      i = 0
      loop {
        idx = i % @members.length
        y << @members[idx]
        i += 1
      }
    }
  end
end

def show_rota(weeks, wday_members, wend_members = wday_members)
  puts "=================================="
  puts "#{weeks} weeks"
  puts "Weekday rota: #{wday_members}"
  puts "Weekend rota: #{wend_members}"
  puts "=================================="
  puts "Mon Tue Wed Thu Fri Sat Sun"

  weekday_rota = Rota.new(wday_members, 5)
  weekend_rota = Rota.new(wend_members, 2)

  wend_last = -1
  weeks.times {|i|
    wday = weekday_rota.take
    wend = weekend_rota.take
		week = (wday + wend)

    comment = ""
    if wend_last == wday.first
      comment << "<-- Sun/Mon in row!"
    end
    if wday.last == wend.first
      comment << "<-- Fri/Sat in row!"
    end
    wend_last = wend.last

    puts "#{week} #{comment}"
  }
end

# with 1 rotation (should conflict)
show_rota(10, 
	[ 1, 2, 3, 4, 5, 6, 7 ],
)

# with 1 long rotation with different orders
show_rota(10, 
	[
		1, 2, 3, 4, 5, 6, 7,
		4, 5, 6, 7, 1, 2, 3,
	],
)

# with 2 layers for weekday/weekend with different orders
show_rota(30,
	[ 1, 2, 3, 4, 5, 6, 7 ],
	[ 1, 2, 3, 4, 5, 6, 7 ],
)


# with 2 layers for weekday/weekend with different orders
show_rota(30,
	[ 1, 2, 3, 4, 5, 6, 7 ],
	[ 1, 7, 6, 5, 4, 3, 2 ],
)

# with 2 layers for weekday/weekend with reversed orders
show_rota(30,
	[ 1, 2, 3, 4, 5, 6, 7 ],
	[ 7, 6, 5, 4, 3, 2, 1 ],
)

output.txt

==================================
10 weeks
Weekday rota: [1, 2, 3, 4, 5, 6, 7]
Weekend rota: [1, 2, 3, 4, 5, 6, 7]
==================================
Mon Tue Wed Thu Fri Sat Sun
[1, 2, 3, 4, 5, 1, 2]
[6, 7, 1, 2, 3, 3, 4] <-- Fri/Sat in row!
[4, 5, 6, 7, 1, 5, 6] <-- Sun/Mon in row!
[2, 3, 4, 5, 6, 7, 1]
[7, 1, 2, 3, 4, 2, 3]
[5, 6, 7, 1, 2, 4, 5]
[3, 4, 5, 6, 7, 6, 7]
[1, 2, 3, 4, 5, 1, 2]
[6, 7, 1, 2, 3, 3, 4] <-- Fri/Sat in row!
[4, 5, 6, 7, 1, 5, 6] <-- Sun/Mon in row!
==================================
10 weeks
Weekday rota: [1, 2, 3, 4, 5, 6, 7, 4, 5, 6, 7, 1, 2, 3]
Weekend rota: [1, 2, 3, 4, 5, 6, 7, 4, 5, 6, 7, 1, 2, 3]
==================================
Mon Tue Wed Thu Fri Sat Sun
[1, 2, 3, 4, 5, 1, 2]
[6, 7, 4, 5, 6, 3, 4]
[7, 1, 2, 3, 1, 5, 6]
[2, 3, 4, 5, 6, 7, 4]
[7, 4, 5, 6, 7, 5, 6]
[1, 2, 3, 1, 2, 7, 1]
[3, 4, 5, 6, 7, 2, 3]
[4, 5, 6, 7, 1, 1, 2] <-- Fri/Sat in row!
[2, 3, 1, 2, 3, 3, 4] <-- Sun/Mon in row!<-- Fri/Sat in row!
[4, 5, 6, 7, 4, 5, 6] <-- Sun/Mon in row!
==================================
30 weeks
Weekday rota: [1, 2, 3, 4, 5, 6, 7]
Weekend rota: [1, 2, 3, 4, 5, 6, 7]
==================================
Mon Tue Wed Thu Fri Sat Sun
[1, 2, 3, 4, 5, 1, 2]
[6, 7, 1, 2, 3, 3, 4] <-- Fri/Sat in row!
[4, 5, 6, 7, 1, 5, 6] <-- Sun/Mon in row!
[2, 3, 4, 5, 6, 7, 1]
[7, 1, 2, 3, 4, 2, 3]
[5, 6, 7, 1, 2, 4, 5]
[3, 4, 5, 6, 7, 6, 7]
[1, 2, 3, 4, 5, 1, 2]
[6, 7, 1, 2, 3, 3, 4] <-- Fri/Sat in row!
[4, 5, 6, 7, 1, 5, 6] <-- Sun/Mon in row!
[2, 3, 4, 5, 6, 7, 1]
[7, 1, 2, 3, 4, 2, 3]
[5, 6, 7, 1, 2, 4, 5]
[3, 4, 5, 6, 7, 6, 7]
[1, 2, 3, 4, 5, 1, 2]
[6, 7, 1, 2, 3, 3, 4] <-- Fri/Sat in row!
[4, 5, 6, 7, 1, 5, 6] <-- Sun/Mon in row!
[2, 3, 4, 5, 6, 7, 1]
[7, 1, 2, 3, 4, 2, 3]
[5, 6, 7, 1, 2, 4, 5]
[3, 4, 5, 6, 7, 6, 7]
[1, 2, 3, 4, 5, 1, 2]
[6, 7, 1, 2, 3, 3, 4] <-- Fri/Sat in row!
[4, 5, 6, 7, 1, 5, 6] <-- Sun/Mon in row!
[2, 3, 4, 5, 6, 7, 1]
[7, 1, 2, 3, 4, 2, 3]
[5, 6, 7, 1, 2, 4, 5]
[3, 4, 5, 6, 7, 6, 7]
[1, 2, 3, 4, 5, 1, 2]
[6, 7, 1, 2, 3, 3, 4] <-- Fri/Sat in row!
==================================
30 weeks
Weekday rota: [1, 2, 3, 4, 5, 6, 7]
Weekend rota: [1, 7, 6, 5, 4, 3, 2]
==================================
Mon Tue Wed Thu Fri Sat Sun
[1, 2, 3, 4, 5, 1, 7]
[6, 7, 1, 2, 3, 6, 5]
[4, 5, 6, 7, 1, 4, 3]
[2, 3, 4, 5, 6, 2, 1]
[7, 1, 2, 3, 4, 7, 6]
[5, 6, 7, 1, 2, 5, 4]
[3, 4, 5, 6, 7, 3, 2]
[1, 2, 3, 4, 5, 1, 7]
[6, 7, 1, 2, 3, 6, 5]
[4, 5, 6, 7, 1, 4, 3]
[2, 3, 4, 5, 6, 2, 1]
[7, 1, 2, 3, 4, 7, 6]
[5, 6, 7, 1, 2, 5, 4]
[3, 4, 5, 6, 7, 3, 2]
[1, 2, 3, 4, 5, 1, 7]
[6, 7, 1, 2, 3, 6, 5]
[4, 5, 6, 7, 1, 4, 3]
[2, 3, 4, 5, 6, 2, 1]
[7, 1, 2, 3, 4, 7, 6]
[5, 6, 7, 1, 2, 5, 4]
[3, 4, 5, 6, 7, 3, 2]
[1, 2, 3, 4, 5, 1, 7]
[6, 7, 1, 2, 3, 6, 5]
[4, 5, 6, 7, 1, 4, 3]
[2, 3, 4, 5, 6, 2, 1]
[7, 1, 2, 3, 4, 7, 6]
[5, 6, 7, 1, 2, 5, 4]
[3, 4, 5, 6, 7, 3, 2]
[1, 2, 3, 4, 5, 1, 7]
[6, 7, 1, 2, 3, 6, 5]
==================================
30 weeks
Weekday rota: [1, 2, 3, 4, 5, 6, 7]
Weekend rota: [7, 6, 5, 4, 3, 2, 1]
==================================
Mon Tue Wed Thu Fri Sat Sun
[1, 2, 3, 4, 5, 7, 6]
[6, 7, 1, 2, 3, 5, 4] <-- Sun/Mon in row!
[4, 5, 6, 7, 1, 3, 2] <-- Sun/Mon in row!
[2, 3, 4, 5, 6, 1, 7] <-- Sun/Mon in row!
[7, 1, 2, 3, 4, 6, 5] <-- Sun/Mon in row!
[5, 6, 7, 1, 2, 4, 3] <-- Sun/Mon in row!
[3, 4, 5, 6, 7, 2, 1] <-- Sun/Mon in row!
[1, 2, 3, 4, 5, 7, 6] <-- Sun/Mon in row!
[6, 7, 1, 2, 3, 5, 4] <-- Sun/Mon in row!
[4, 5, 6, 7, 1, 3, 2] <-- Sun/Mon in row!
[2, 3, 4, 5, 6, 1, 7] <-- Sun/Mon in row!
[7, 1, 2, 3, 4, 6, 5] <-- Sun/Mon in row!
[5, 6, 7, 1, 2, 4, 3] <-- Sun/Mon in row!
[3, 4, 5, 6, 7, 2, 1] <-- Sun/Mon in row!
[1, 2, 3, 4, 5, 7, 6] <-- Sun/Mon in row!
[6, 7, 1, 2, 3, 5, 4] <-- Sun/Mon in row!
[4, 5, 6, 7, 1, 3, 2] <-- Sun/Mon in row!
[2, 3, 4, 5, 6, 1, 7] <-- Sun/Mon in row!
[7, 1, 2, 3, 4, 6, 5] <-- Sun/Mon in row!
[5, 6, 7, 1, 2, 4, 3] <-- Sun/Mon in row!
[3, 4, 5, 6, 7, 2, 1] <-- Sun/Mon in row!
[1, 2, 3, 4, 5, 7, 6] <-- Sun/Mon in row!
[6, 7, 1, 2, 3, 5, 4] <-- Sun/Mon in row!
[4, 5, 6, 7, 1, 3, 2] <-- Sun/Mon in row!
[2, 3, 4, 5, 6, 1, 7] <-- Sun/Mon in row!
[7, 1, 2, 3, 4, 6, 5] <-- Sun/Mon in row!
[5, 6, 7, 1, 2, 4, 3] <-- Sun/Mon in row!
[3, 4, 5, 6, 7, 2, 1] <-- Sun/Mon in row!
[1, 2, 3, 4, 5, 7, 6] <-- Sun/Mon in row!
[6, 7, 1, 2, 3, 5, 4] <-- Sun/Mon in row!