=begin
#===============================================================================
 Title: Conditional Effects
 Author: Hime
 Date: Mar 16, 2014
 URL: http://www.himeworks.com/2014/03/16/conditional-effects-2/
--------------------------------------------------------------------------------
 ** Change log
 Mar 16, 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 assign custom conditions to skill or item effects.
 Effects are only executed if they meet the conditions.
 
 Conditions are specified as a formula, so you can create any condition that
 you can think of as long as you can write it.
 
--------------------------------------------------------------------------------
 ** Installation
 
 Place this script below Materials and above Main

--------------------------------------------------------------------------------
 ** Usage 
 
 To specify a condition for an effect, note-tag skills or items with
 
   <effect condition: ID>
     FORMULA
   </effect condition>
   
 Where the ID is the ID of the effect that you want to assign the condition to.
 You can determine an effect's ID by counting their position on the list,
 so the first effect has ID 1, second effect has ID 2, and so on.
 
 As a shortcut, you can assign a condition to multiple effects by specifying
 multiple ID's separated by commas like this
 
   <effect condition: 1,2,3>
     FORMULA
   </effect condition>
   
 The formula can be anything that returns true or false.
 The following formula variables are available
 
    a - user of the action
    b - target of the action
    i - item used
    t - game troop
    p - game party
    s - game switches
    v - game variables
    
 The formula is evaluated within the context of the effect, so any of the
 effect's attributes can be referenced as well (eg: data_id, code)   
 
#===============================================================================
=end
$imported = {} if $imported.nil?
$imported[:TH_ConditionalEffects] = true
#===============================================================================
# ** Configuration
#===============================================================================
module TH
  module Conditional_Effects
    Ext_Regex = /<effect[-_ ]condition:\s*(.*?)\s*>(.*?)<\/effect[-_ ]condition>/im
  end
end
#===============================================================================
# ** Rest of Script
#===============================================================================
module RPG
  class UsableItem
    
    alias :th_conditional_effects_effects :effects
    def effects
      load_notetag_conditional_effects unless @effect_conditions_checked
      th_conditional_effects_effects
    end
    
    def load_notetag_conditional_effects
      @effect_conditions_checked = true
      effect_conditions = []
      results = self.note.scan(TH::Conditional_Effects::Ext_Regex)
      results.each do |res|
        ids = res[0].split(",").map {|id| id.to_i}
        condition = res[1]
        
        cond = Data_EffectCondition.new
        cond.condition = condition
        
        ids.each do |id|
          self.effects[id-1].effect_condition = cond
        end
      end
    end
  end
    
  class UsableItem::Effect
    attr_accessor :effect_condition
    
    def condition_met?(user, target, item)
      return true unless @effect_condition
      @effect_condition.condition_met?(user, target, item)
    end
  end
end

class Data_EffectCondition
  attr_accessor :condition
  
  def initialize
    @condition = "true"
  end
  
  def condition_met?(a, b, i, p=$game_party, t=$game_troop, s=$game_switches, v=$game_variables)
    eval(@condition)
  end
end

class Game_Battler < Game_BattlerBase
  
  alias :th_conditional_effects_item_effect_apply :item_effect_apply
  def item_effect_apply(user, item, effect)
    return unless effect.condition_met?(user, self, item)
    th_conditional_effects_item_effect_apply(user, item, effect)
  end
end