module DoubleRoundRobinSchedule

# File lib/double_round_robin_schedule.rb, line 6
def self.schedule(all_teams)
      numweeks = (all_teams.length - 1) * 2
  halfsize = all_teams.length / 2

  teams = all_teams.dup
  temp = all_teams.dup
  teams.shift
  team_size = teams.length
  week = 0
  games = []

  while( week < numweeks) do 
      week_matches = []
    if (week % 2 == 0)
      teamIdx = week % team_size
      week_matches <<  [teams[teamIdx],  temp[0] ]
      idx = 0
      while( idx < halfsize) do 
        firstTeam = (week + idx) % team_size
        secondTeam = ((week + team_size) - idx) % team_size
        week_matches <<  [teams[firstTeam], teams[secondTeam] ] if (firstTeam != secondTeam)
        idx = idx + 1
      end
    end

    if (week % 2 != 0)
      teamIdx = week % team_size
      week_matches <<  [temp[0] , teams[teamIdx]] 
      idx = 0
              while( idx < halfsize) do 
        firstTeam = (week + idx) % team_size
        secondTeam = ((week + team_size) - idx) % team_size
        week_matches <<  [teams[secondTeam], teams[firstTeam]] if (firstTeam != secondTeam)
        idx = idx + 1
      end
    end
    games[week] ||= []
    games[week] += week_matches
    week = week + 1
  end  
  games
end