Build a framework for a maintainable combat plugin

* Uses a hierarchy of WeaponClasses -> Weapons for performing attacks,
  with WeaponClass having a set of styles and associated Attacks for
  those styles. Weapons and their classes are built with an easy to use
  and clean DSL.

* Adds a BonusContainer mixin, so that Equipment, Weapons, and
  WeaponClasses can all have their own set of bonuses which apply to the
  player.

* Allows attacks to be queued to the Mobs CombatState instance from
  external code, allowing e.g., NPCs or auto-cast to queue attacks to be
  executed.

data/plugins/combat/attack.rb

@@ -0,0 +1,88 @@
+java_import 'org.apollo.cache.def.ItemDefinition'
+java_import 'org.apollo.game.model.Animation'
+java_import 'org.apollo.game.model.Graphic'
+
+class BaseAttack
+  attr_reader :requirements, :range
+
+  def initialize(animation, graphic = nil, range = 1, requirements = [])
+    @animation    = animation
+    @graphic      = graphic
+    @range        = range
+    @requirements = requirements
+  end
+
+  def do(source, target)
+    source.play_animation(Animation.new(@animation))
+
+    unless @graphic.nil?
+      if @graphic.is_a?(Hash)
+        source.play_graphic(Graphic.new(@graphic[:id], @graphic[:delay] || 0, @graphic[:height] | 0))
+      else
+        source.play_graphic(Graphic.new(@graphic))
+      end
+    end
+
+    apply(source, target)
+  end
+
+  def apply(source, target)
+    raise "BaseAttack#apply unimplemented"
+  end
+
+  def damage!(source, target, amount, delay = 0)
+    schedule delay do |task|
+      task.stop && return if source.dead or target.dead
+
+      target_combat_state = get_combat_state target
+      target_hitpoints    = target.skill_set.get_skill(Skill::HITPOINTS).get_current_level
+      amount              = target_hitpoints if target_hitpoints < amount
+
+      type = amount > 0 ? 1 : 0
+      target.play_animation(Animation.new(424)) unless target_combat_state.state == :attacking
+      target.damage(amount, type, false)
+
+      task.stop
+    end
+  end
+end
+
+class ProcAttack < BaseAttack
+  def initialize(block, animation:, graphic:, range: 1, requirements: [])
+    super(animation, graphic, range, requirements)
+
+    @block = block
+  end
+
+  def apply(source, target)
+    self.instance_exec(source, target, &@block)
+  end
+end
+
+class RangedAttack < BaseAttack
+  def initialize(animation:, graphic:, requirements: [])
+
+  end
+
+  def calculate_delay(source, target)
+
+  end
+
+  def apply(source, target)
+
+  end
+
+  def projectile!(source, target, projectile_id)
+
+  end
+end
+
+class Attack < BaseAttack
+  def initialize(animation:, graphic: nil, range: 1, requirements: [])
+    super(animation, graphic, range, requirements)
+  end
+
+  def apply(source, target)
+    damage! source, target, CombatUtil::calculate_hit(source, target)
+  end
+end