=begin
#===============================================================================
 Title: Gain Exp Effect
 Author: Hime
 Date: May 7, 2015
--------------------------------------------------------------------------------
 ** Change log
 May 7, 2015
   - 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 create an effect for your skills and items that
 will add (or remove) exp from the target.
 
--------------------------------------------------------------------------------
 ** Installation
 
 In the script editor (F11), place this script below Materials and above Main

--------------------------------------------------------------------------------
 ** Usage 
 
 Add the note-tag to skills or items
 
   <eff: gain_exp>
     FORMULA
   </eff: gain_exp>
   
 Where the FORMULA is any valid formula that determines how much EXP you
 will gain or lose.
 
 The following formula variables are supported
 
   a - user of the item/skill
   b - target of the item/skill (the one that will gain/lose exp
   v - game variables
   s - game switches
   p - game party
   t - game troop
  
#===============================================================================
=end
$imported = {} if $imported.nil?
$imported[:th_gain_exp_effect] = true
#===============================================================================
# ** Configuration
#===============================================================================
module TH
  class Gain_Exp_Effect    
    Regex = /<eff:\s*gain[-_ ]exp>(.+?)<\/eff:\s*gain[-_ ]exp>/im
  end
end
#===============================================================================
# ** Rest of script
#===============================================================================
module RPG  
  class UsableItem
    
    alias :th_gain_exp_effect_effects :effects
    def effects
      load_notetag_effects_gain_exp unless @exp_gain_effects_parsed
      th_gain_exp_effect_effects
    end
    
    def load_notetag_effects_gain_exp
      @exp_gain_effects_parsed = true
      results = self.note.scan(TH::Gain_Exp_Effect::Regex)
      results.each do |res|
        code = :GAIN_EXP
        formula = res[0]
        self.effects << RPG::UsableItem::Effect.new(code, 0, formula)
      end
    end
  end
  
  class UsableItem::Effect
    def eval_exp_gain(a, b, s=$game_switches, v=$game_variables, t=$game_troop, p=$game_party)
      eval(self.value1)
    end
  end
end

class Game_Battler  
  alias :th_gain_exp_effect_item_effect_apply :item_effect_apply
  def item_effect_apply(user, item, effect)
    if effect.code == :GAIN_EXP
      item_effect_gain_exp(user, item, effect) 
    else    
      th_gain_exp_effect_item_effect_apply(user, item, effect)
    end
  end
  
  def item_effect_gain_exp(user, item, effect)    
    # stub
  end
end

class Game_Actor < Game_Battler
  def item_effect_gain_exp(user, item, effect)
    exp = effect.eval_exp_gain(user, self)
    self.gain_exp(exp)
  end
end