=begin
#===============================================================================
 Title: Action Speed Formula
 Author: Hime
 Date: Mar 22, 2014
 URL: http://www.himeworks.com/2014/03/22/action-speed-formulas/
--------------------------------------------------------------------------------
 ** Change log
 Mar 22, 2014
   - Initial release
--------------------------------------------------------------------------------   
 ** Terms of Use
 * Free to use in non-commercial projects
 * Contact me for commercial use
 * No real support. The script is provided as-is
 * Will do bug fixes, but no compatibility patches
 * Features may be requested but no guarantees, especially if it is non-trivial
 * Credits to Hime Works in your project
 * Preserve this header
--------------------------------------------------------------------------------
 ** Description
 
 This script allows you to specify action speed formulas for your database
 objects.
 
 An action speed formula allows you to use a formula to calculate a battler's
 action speed. For example, suppose you had a "Haste" state that doubles your
 action speed.
 
 In the default battle system, action speed determines who will act first.
 Battlers with higher action speeds can perform their actions before battlers
 with lower action speeds.
 
 The default speed calculations considers three things:
 
   - the battler's agi, using the formula (agi + rand(5 + agi / 4))
   - the skill/item's invocation speed, if a skill/item is used
   - any "atk speed" features, if the skill used is the "attack" skill
   
 The formulas provided by this script first calculates the base speed
 from above and then passes it to custom formulas that you define.
 
--------------------------------------------------------------------------------
 ** Installation
 
 In the script editor, place this script below Materials and above Main

--------------------------------------------------------------------------------
 ** Usage 
 
 To specify an action speed formula, note-tag an object with
 
   <speed formula>
      FORMULA
   </speed formula>
   
 Where the formula is any valid formula that evaluates to a number.
 The following formula variables are supported:
 
   speed - the current speed, after any modifiers
   a - the current battler
   p - game party
   t - game troop
   s - game switches
   v - game variables
   
 The following database objects support speed formulas:
 Actors, Classes, Items, Skills, Weapons, Armors, Enemies, States
 
--------------------------------------------------------------------------------
 ** Example
 
 To implement a "haste" state that doubles your action speed, you would notetag
 the state with
 
   <speed formula>
     speed * 2
   </speed formula>
 
#===============================================================================
=end
$imported = {} if $imported.nil?
$imported[:TH_ActionSpeedFormula] = true
#===============================================================================
# ** Configuration
#===============================================================================
module TH
  module Action_Speed_Formula    
    Ext_Regex = /<speed[-_ ]formula>(.*?)<\/speed[-_ ]formula>/im    
  end
end
#===============================================================================
# ** Rest of script
#===============================================================================
module RPG
  class BaseItem
    
    def speed_formula
      load_notetag_action_speed_formula unless @speed_formula
      return @speed_formula
    end
    
    def load_notetag_action_speed_formula
      @speed_formula = ""
      res = self.note.match(TH::Action_Speed_Formula::Ext_Regex)
      if res
        @speed_formula = res[1]
      end
    end
    
    def eval_speed_formula(speed, p=$game_party, t=$game_troop, s=$game_switches, v=$game_variables)
      eval(self.speed_formula)
    end
  end
end
class Game_Action
  
  alias :th_action_speed_modifiers_speed :speed
  def speed
    speed = th_action_speed_modifiers_speed
    speed = item.eval_speed_formula(speed) if item && !item.speed_formula.empty?
    speed = subject.apply_speed_modifiers(speed)
    speed
  end  
end

class Game_Battler < Game_BattlerBase
  
  def speed_modifier_objects
    states
  end
  
  def apply_speed_modifiers(speed)
    speed_modifier_objects.each do |obj|
      speed = obj.eval_speed_formula(speed) unless obj.speed_formula.empty?
    end
    return speed
  end
end

class Game_Actor < Game_Battler
  
  alias :th_action_speed_modifiers_speed_modifier_objects :speed_modifier_objects
  def speed_modifier_objects
    th_action_speed_modifiers_speed_modifier_objects + [actor] + [self.class] + equips.compact
  end
end

class Game_Enemy < Game_Battler
  
  alias :th_action_speed_modifiers_speed_modifier_objects :speed_modifier_objects
  def speed_modifier_objects
    th_action_speed_modifiers_speed_modifier_objects + [enemy]
  end
end