require "i18n"

module FriendlyId
  # @guide begin
  #
  # ## Translating Slugs Using Simple I18n
  #
  # The {FriendlyId::SimpleI18n SimpleI18n} module adds very basic i18n support to
  # FriendlyId.
  #
  # In order to use this module, your model must have a slug column for each locale.
  # By default FriendlyId looks for columns named, for example, "slug_en",
  # "slug_es", "slug_pt_br", etc. The first part of the name can be configured by
  # passing the `:slug_column` option if you choose. Note that the column for the
  # default locale must also include the locale in its name.
  #
  # This module is most suitable to applications that need to support few locales.
  # If you need to support two or more locales, you may wish to use the
  # friendly_id_globalize gem instead.
  #
  # ### Example migration
  #
  #     def self.up
  #       create_table :posts do |t|
  #         t.string :title
  #         t.string :slug_en
  #         t.string :slug_es
  #         t.string :slug_pt_br
  #         t.text   :body
  #       end
  #       add_index :posts, :slug_en
  #       add_index :posts, :slug_es
  #       add_index :posts, :slug_pt_br
  #     end
  #
  # ### Finds
  #
  # Finds will take into consideration the current locale:
  #
  #     I18n.locale = :es
  #     Post.friendly.find("la-guerra-de-las-galaxias")
  #     I18n.locale = :en
  #     Post.friendly.find("star-wars")
  #     I18n.locale = :"pt-BR"
  #     Post.friendly.find("guerra-das-estrelas")
  #
  # To find a slug by an explicit locale, perform the find inside a block
  # passed to I18n's `with_locale` method:
  #
  #     I18n.with_locale(:es) do
  #       Post.friendly.find("la-guerra-de-las-galaxias")
  #     end
  #
  # ### Creating Records
  #
  # When new records are created, the slug is generated for the current locale only.
  #
  # ### Translating Slugs
  #
  # To translate an existing record's friendly_id, use
  # {FriendlyId::SimpleI18n::Model#set_friendly_id}. This will ensure that the slug
  # you add is properly escaped, transliterated and sequenced:
  #
  #     post = Post.create :name => "Star Wars"
  #     post.set_friendly_id("La guerra de las galaxias", :es)
  #
  # If you don't pass in a locale argument, FriendlyId::SimpleI18n will just use the
  # current locale:
  #
  #     I18n.with_locale(:es) do
  #       post.set_friendly_id("La guerra de las galaxias")
  #     end
  #
  # @guide end
  module SimpleI18n
    # FriendlyId::Config.use will invoke this method when present, to allow
    # loading dependent modules prior to overriding them when necessary.
    def self.setup(model_class)
      model_class.friendly_id_config.use :slugged
    end

    def self.included(model_class)
      model_class.class_eval do
        friendly_id_config.class.send :include, Configuration
        include Model
      end
    end

    module Model
      def set_friendly_id(text, locale = nil)
        I18n.with_locale(locale || I18n.locale) do
          set_slug(normalize_friendly_id(text))
        end
      end

      def slug=(value)
        super
        write_attribute friendly_id_config.slug_column, value
      end
    end

    module Configuration
      def slug_column
        "#{super}_#{locale_suffix}"
      end

      private

      def locale_suffix
        I18n.locale.to_s.underscore
      end
    end
  end
end