War - Battle System

war.exs

defmodule Die do
  def init(), do: :random.seed(:erlang.now)
  def d6(), do: :random.uniform(6)
  def d100(), do: :random.uniform(100)
end

defmodule War do
  def create_player(name, skill, hp) do
    [ name: name, skill: skill, hp: hp ]
  end

  def name(p), do: p[:name]
  def skill(p), do: p[:skill]
  def hp(p), do: p[:hp]
  def to_s(p), do: "Name: #{name(p)} Skill: #{skill(p)} HP: #{hp(p)}"
  def pr_hit(p1, p2, roll), do: IO.puts "#{name(p1)} has hit #{name(p2)} with a roll of #{roll}"
  def pr_miss(p1, _, roll), do: IO.puts "#{name(p1)} missed with a roll of #{roll}"

  def attack([p1, p2]) do
    roll = Die.d100()
    if roll <= skill(p1) do
      pr_hit p1, p2, roll
      [p1, p2, true]
    else
      pr_miss p1, p2, roll
      [p1, p2, false]
    end
  end

  def defend([p1, p2, result_att]) do
    if result_att do
      roll = Die.d100()
      if roll <= skill(p2) do
        IO.puts "#{name(p2)} has defended with a roll of #{roll}"
        [p1, p2, result_att, true]
      else
        IO.puts "#{name(p2)} has FAILED to defend with a roll of #{roll}"
        [p1, p2, result_att, false]
      end
    else
      [p1, p2, result_att, false]
    end
  end

  def calcdmg([p1, p2, result_att, result_dfnd]) do
    if result_att and not result_dfnd do
      IO.puts "\tCalculating damage"
      IO.puts "\t#{name(p2)} was hit!"
      dmg = Die.d6()
      newHP = hp(p2) - dmg
      IO.puts "\tDamage: #{dmg}"
      p2 = War.create_player(p2[:name], p2[:skill], newHP)
      IO.puts "\tNew charpoints: #{to_s(p2)}"
    end
    [p2, p1]
  end

  def is_dead(someone) do
    if hp(someone) < 0 do
      true
    else
      false
    end
  end

  def war_loop([p1, p2]) do
    if is_dead(p1) or is_dead(p2) do
      :ok
    else
      [p1, p2] |> War.attack |> War.defend |> War.calcdmg |> War.war_loop
    end
  end
end

Die.init()
conan = War.create_player("Conan", 70, 20)
urg   = War.create_player("Urg", 65, 25)

IO.puts War.to_s(conan)
IO.puts War.to_s(urg)
#kickoff the loop
War.war_loop([conan, urg])
IO.puts "The end"