design.org

Design

defmodule Dwarf do
  use Ecstatic.Entity
  @default_components [Age, Health.new(%{points: 20})]
end

defmodule Health do
  use Ecstatic.Component
  @default_values %{points: 10}
end

defmodule Poison do
  use Ecstatic.Component
  @default_values %{health_loss: 2}
end

defmodule Age do
  use Ecstatic.Component
  @default_values %{points: 1}
end

defmodule AgingSpell do
  use Ecstatic.Component
  @default_values %{modifier: 1.2}
end

defmodule Poisoned do
  use Ecstatic.Aspect
  @with [Health, Poison]
  @without [ImmuneToPoison]
end

defmodule PoisonSystem do
  use Ecstatic.System
  aspect Poisoned
  def process(entity) do
    health = Entity.find_component(entity, Health)
    %Ecstatic.Changeset{changed: [%{health | points: health.points - 1}]}
  end
end

defmodule Watchers do
  use Ecstatic.Watchers

  watch Poison do
    run PoisonSystem, every: 6, :seconds
  end

  watch Health do
    run PanicSystem, when: fn(pre, post) -> (pre.points - post.points) > 30 end
    run BleedingSystem, when: fn(_pre, post) -> post.points == 0 end
    run DeathSystem, when: fn(_pre, post) -> post.points == -10 end
  end

end