Give it a few weeks and we'll be selling this to Premier League clubs ;)

team_picker.rb

#!/usr/bin/env ruby

class Manager

  def initialize
    puts "Manager initialised"
  end

  def pick_a_team(squad, d, m, a)
    team = Team.new
    team << squad.best_player(:goalkeeper)
    d.times do |i|
      team << squad.best_player(:defender)
    end
    m.times do |i|
      team << squad.best_player(:midfielder)
    end
    a.times do |i|
      team << squad.best_player(:attacker)
    end
    team
  end
end

class Coach

  def calculate_form(player)
    player.form = player.skill * (rand(10) +1)
  end

end

class Player

  attr_accessor :form
  attr_reader :skill, :position

  def initialize(name, position, skill, injured=false)
    @name, @position, @skill, @injured = name, position, skill, injured

  end

  def to_s
    #player_array = [@name, @position, @skill, @injured]
    "My name is #{@name}, my position is #{@position}, my skill level is #{@skill} and I am injured? #{@injured} and my form is #{@form}"
  end
end

class Team
  attr_reader :players

  def initialize
    @players = []
  end

  def <<(player)  # how to call it: team << player
    # raise an error if we can't add the player,
    # e.g. if we already have the position filled
    # raise "Can't add #{position}"
    @players << player
  end

  def to_s
    "I'm playing as #{position} because my form is #{form}"
  end
end


class Squad

  attr_reader :players

  def initialize
    @players = []
    @coach = Coach.new
  end

  def <<(player)
    @coach.calculate_form(player)
    @players << player
  end

  def best_player(position)
    player = @players.select{|p| p.position == position}.sort_by{|p| p.form}.last
    @players.delete_if {|x| x == player}     # remove the player from @players
    # what if player.nil? maybe raise an exception
    player
  end

end

def squad_with_players
  squad = Squad.new
  2.times do |i|
    squad << Player.new("Goalkeeper #{i}", :goalkeeper, rand(10) + 1, false)
  end
  8.times do |i|
    squad << Player.new("Defender #{i}", :defender, rand(10) + 1, false)
  end
  8.times do |i|
    squad << Player.new("Midfielder #{i}", :midfielder, rand(10) + 1, false)
  end
  4.times do |i|
    squad << Player.new("Attacker #{i}", :attacker, rand(10) + 1, false)
  end
  squad
end


first_squad = squad_with_players

puts "*****************************     Assigned 22 players to the squad"


puts "here are the details of your squad"

first_squad.players.each {|player| puts player}

puts "******Initialising coach"

puts "Initialising a new manager"

manager = Manager.new()

puts "And now to pick the team"

team = manager.pick_a_team(first_squad, 2,7, 0)

puts "

Our chosen team:"

team.players.each {|player| puts player.to_s}