# redMine - project management software
# Copyright (C) 2006  Jean-Philippe Lang
#
# 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.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

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

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

  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 before_save
    if is_default? && is_default_changed?
      Enumeration.update_all("is_default = #{connection.quoted_false}", {:type => type})
    end
  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

  # Returns the Subclasses of Enumeration.  Each Subclass needs to be
  # required in development mode.
  #
  # Note: subclasses is protected in ActiveRecord
  def self.get_subclasses
    @@subclasses[Enumeration]
  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

# Force load the subclasses in development mode
require_dependency 'time_entry_activity'
require_dependency 'document_category'
require_dependency 'issue_priority'
