require 'dm-core'

DataMapper.setup :default,
                 :adapter => 'postgres',
                 :host => 'localhost',
                 :port => 5432,
                 :username => 'dofus_treasury',
                 :password => 'dofus_treasury',
                 :database => 'dofus_treasury'

# Items are identified by names, for example, Bread
# A recipe has one product item, and a few ingredient items each dosed with a
# quantity, for example, Bread = 2 Flour + 1 Yeast + 1 Water
# A dosage is to used to hold one ingredient item and its quantity

class Item
  include DataMapper::Resource

  property :name, String, :key => true
  has n, :dosages

  def self.named(name)
    first_or_create(:name => name)
  end
end

class Dosage
  include DataMapper::Resource

  property :id, Serial
  property :quantity, Integer
  belongs_to :item
  belongs_to :recipe
end

class Recipe
  include DataMapper::Resource

  property :id, Serial
  has 1, :product, :class_name => 'Item'
  has n, :dosages
  has n, :ingredients, :class_name => 'Item', :through => :dosages,
         :remote_relationship_name => :item

  # return recipe with the given product and ingredient/quantities,
  # creating if not existing
  #
  # Recipe.defined( Item.named('Bread'),
  #                 Item.named('Flour') => 2
  #                 Item.named('Yeast') => 1
  #                 Item.named('Water') => 1 )
  def self.defined(product, ingredients_and_quantities)
    # how do I find an existing recipe with the given product,
    # and quantities and ingredients?
    first(:product => product,
          :ingredients => ingredienst_and_quantities.keys,
          :dosages.all? {|d| ingredients_and_quantities[d.item] == d.quantity}
          # how to translate to query?
         ) or
    begin
      r = Recipe.new
      r.product = product
      quantities_and_ingredients.each_pair do |ingredient, quantity|
        r.dosages << Dosage.new(:quantity => quantity, :item => ingredient)
      end
      r
    end
  end
end

DataMapper.auto_migrate!

Recipe.defined( Item.named('Bread'),
                Item.named('Flour') => 2
                Item.named('Yeast') => 1
                Item.named('Water') => 1 )