rgravina/okubo

module Okubo
  class Deck < ActiveRecord::Base
    include Enumerable
    include Okubo::Base
    self.table_name = "okubo_decks"
    belongs_to :user, :polymorphic => true
    has_many :items, :class_name => "Okubo::Item", :dependent => :destroy

    def each(&block)
      _items.each do |item|
        if block_given?
          block.call item
        else
          yield item
        end
      end
    end

    def ==(other)
      _items == other
    end

    def _items
      source_class.find(self.items.pluck(:source_id))
    end

    def <<(source)
      raise ArgumentError.new("Word already in the stack") if include?(source)
      self.items << Okubo::Item.new(:deck => self, :source_id => source.id, :source_type => source.class.name)
    end

    def self.add_deck(user)
      create!(user)
    end

    def delete(source)
      item = Okubo::Item.new(:deck => self, :source_id => source.id, :source_type => source.class.name)
      item.destroy
    end

    #
    # Returns a suggested word review sequence.
    #
    def review
      [:untested, :failed, :expired].inject([]) do |words, s| 
        words += self.items.send(s).order('random()').map(&:source)
      end
    end

    def next
      word = nil
      [:untested, :failed, :expired].each do |category|
        word = self.items.send(category).order('random()').limit(1).map(&:source).first
        break if word
      end
      word
    end

    def last
      self.items.order('created_at desc').limit(1).first.try(:source)
    end

    def untested
      source_class.find(self.items.untested.pluck(:source_id))
    end

    def failed
      source_class.find(self.items.failed.pluck(:source_id))
    end

    def known
      source_class.find(self.items.known.pluck(:source_id))
    end

    def expired
      source_class.find(self.items.expired.pluck(:source_id))
    end

    def box(number)
      source_class.find(self.items.where(:box =>  number).pluck(:source_id))
    end

    def source_class
      user.deck_name.to_s.singularize.titleize.constantize
    end
  end
end