module Selections
  class Selection < ActiveRecord::Base

    VERSION = "0.1"
    HIDDEN_POSITION = 999888777

    acts_as_tree

    validate :name, :existence =>true
    validates_presence_of :name
    validates_uniqueness_of :name, :scope => :parent_id
    validates_uniqueness_of :system_code, :scope => :archived_at
    validates_format_of :system_code, :with => /^[a-z][a-zA-Z_0-9]*$/, :message => "can only contain alphanumeric characters and '_', not spaces"

    before_validation :auto_gen_system_code, :on => :create
    before_validation :disable_system_code_change, :on => :update
    after_validation :check_defaults

    default_scope :order => [:position_value, :name]

    scope :filter_archived_except_selected, lambda { |selected_id| {:conditions => ["archived_at is ? or id = ?", nil, selected_id]} }

    def to_s
      name.to_s
    end

    def position=(value)
      self.position_value = value || HIDDEN_POSITION
    end

    def disable_system_code_change
      errors.add(:system_code, "cannot be changed") if system_code_changed?
    end

    def position
       position_value unless position_value == HIDDEN_POSITION
    end

    def auto_gen_system_code
      unless system_code
        if parent
          self.system_code = parent.system_code + "_" + name.to_s.underscore.split(" ").join("_").singularize.underscore
        else
          self.system_code = name.to_s.underscore.split(" ").join("_").singularize.underscore
        end
      end
    end

    def check_defaults
      siblings_with_default_set.update_attribute(:is_default, false) if self.parent && siblings_with_default_set && self.is_default
      self.is_default = false if archived
    end

    def siblings_with_default_set
      self.parent.children.where(:is_default => true).where("id != #{self.id.to_i}").first
    end

    def
    self.method_missing lookup_code, *options
      if (scope = Selection.where(:system_code => lookup_code.to_s)) && scope.exists?
        scope.first
      elsif (scope = Selection.where(:system_code => lookup_code.to_s.singularize)) && scope.exists?
        scope.first.children
      else
        super
      end
    end

    def archived
      !!archived_at
    end

    def archived=(archived_set)
      if archived_set
        self.archived_at = Time.now unless archived_at
      else
        self.archived_at = nil
      end
    end

  end
end