#-- encoding: UTF-8
#-- copyright
# ChiliProject is a project management system.
#
# Copyright (C) 2010-2011 the ChiliProject Team
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# See doc/COPYRIGHT.rdoc for more details.
#++

class Enumeration < ActiveRecord::Base
  default_scope :order => "#{Enumeration.table_name}.position ASC"

  belongs_to :project

  acts_as_list :scope => 'type = \'#{type}\''
  acts_as_customizable
  acts_as_tree :order => 'position ASC'

  before_destroy :check_integrity

  attr_protected :project_id

  validates_presence_of :name
  validates_uniqueness_of :name, :scope => [:type, :project_id]
  validates_length_of :name, :maximum => 30

  scope :shared, :conditions => { :project_id => nil }
  scope :active, :conditions => { :active => true }

  before_save :unmark_old_default_value, :if => :became_default_value?

  # let all child classes have Enumeration as it's model name
  # used to not having to create another route for every subclass of Enumeration
  def self.inherited(child)
    child.instance_eval do
      def model_name
        Enumeration.model_name
      end
    end
    super
  end

  def self.default
    # Creates a fake default scope so Enumeration.default will check
    # it's type.  STI subclasses will automatically add their own
    # types to the finder.
    if self.descends_from_active_record?
      find(:first, :conditions => { :is_default => true, :type => 'Enumeration' })
    else
      # STI classes are
      find(:first, :conditions => { :is_default => true })
    end
  end

  # Overloaded on concrete classes
  def option_name
    nil
  end

  def became_default_value?
    is_default? && is_default_changed?
  end

  def unmark_old_default_value
    Enumeration.update_all("is_default = #{connection.quoted_false}", {:type => type})
  end

  # Overloaded on concrete classes
  def objects_count
    0
  end

  def in_use?
    self.objects_count != 0
  end

  # Is this enumeration overiding a system level enumeration?
  def is_override?
    !self.parent.nil?
  end

  alias :destroy_without_reassign :destroy

  # Destroy the enumeration
  # If a enumeration is specified, objects are reassigned
  def destroy(reassign_to = nil)
    if reassign_to && reassign_to.is_a?(Enumeration)
      self.transfer_relations(reassign_to)
    end
    destroy_without_reassign
  end

  def <=>(enumeration)
    position <=> enumeration.position
  end

  def to_s; name end

  # Does the +new+ Hash override the previous Enumeration?
  def self.overridding_change?(new, previous)
    if (same_active_state?(new['active'], previous.active)) && same_custom_values?(new,previous)
      return false
    else
      return true
    end
  end

  # Does the +new+ Hash have the same custom values as the previous Enumeration?
  def self.same_custom_values?(new, previous)
    previous.custom_field_values.each do |custom_value|
      if custom_value.value != new["custom_field_values"][custom_value.custom_field_id.to_s]
        return false
      end
    end

    return true
  end

  # Are the new and previous fields equal?
  def self.same_active_state?(new, previous)
    new = (new == "1" ? true : false)
    return new == previous
  end

private
  def check_integrity
    raise "Can't delete enumeration" if self.in_use?
  end

end

# TODO: needed? redmine doesn't
# Force load the subclasses in development mode
# require 'time_entry_activity'
# require 'document_category'
# require 'issue_priority'