module FriendlyId
  # The configuration paramters passed to {Base#friendly_id} will be stored in
  # this object.
  class Configuration

    attr_writer :base

    # The default configuration options.
    attr_reader :defaults

    # The modules in use
    attr_reader :modules

    # The model class that this configuration belongs to.
    # @return ActiveRecord::Base
    attr_accessor :model_class

    # The module to use for finders
    attr_accessor :finder_methods

    def initialize(model_class, values = nil)
      @model_class    = model_class
      @defaults       = {}
      @modules        = []
      @finder_methods = FriendlyId::FinderMethods
      set values
    end

    # Lets you specify the addon modules to use with FriendlyId.
    #
    # This method is invoked by {FriendlyId::Base#friendly_id friendly_id} when
    # passing the `:use` option, or when using {FriendlyId::Base#friendly_id
    # friendly_id} with a block.
    #
    # @example
    #   class Book < ActiveRecord::Base
    #     extend FriendlyId
    #     friendly_id :name, :use => :slugged
    #   end
    #
    # @param [#to_s,Module] modules Arguments should be Modules, or symbols or
    #   strings that correspond with the name of an addon to use with FriendlyId.
    #   By default FriendlyId provides `:slugged`, `:history`, `:simple_i18n`,
    #   and `:scoped`.
    def use(*modules)
      modules.to_a.flatten.compact.map do |object|
        mod = get_module(object)
        mod.setup(@model_class) if mod.respond_to?(:setup)
        @model_class.send(:include, mod) unless uses? object
      end
    end

    # Returns whether the given module is in use.
    def uses?(mod)
      @model_class < get_module(mod)
    end

    # The column that FriendlyId will use to find the record when querying by
    # friendly id.
    #
    # This method is generally only used internally by FriendlyId.
    # @return String
    def query_field
      base.to_s
    end

    # The base column or method used by FriendlyId as the basis of a friendly id
    # or slug.
    #
    # For models that don't use {FriendlyId::Slugged}, this is the column that
    # is used to store the friendly id. For models using {FriendlyId::Slugged},
    # the base is a column or method whose value is used as the basis of the
    # slug.
    #
    # For example, if you have a model representing blog posts and that uses
    # slugs, you likely will want to use the "title" attribute as the base, and
    # FriendlyId will take care of transforming the human-readable title into
    # something suitable for use in a URL.
    #
    # If you pass an argument, it will be used as the base. Otherwise the current
    # value is returned.
    #
    # @param value A symbol referencing a column or method in the model. This
    #   value is usually set by passing it as the first argument to
    #   {FriendlyId::Base#friendly_id friendly_id}.
    def base(*value)
      if value.empty?
        @base
      else
        self.base = value.first
      end
    end

    private

    def get_module(object)
      Module === object ? object : FriendlyId.const_get(object.to_s.titleize.camelize.gsub(/\s+/, ''))
    end

    def set(values)
      values and values.each {|name, value| self.send "#{name}=", value}
    end
  end
end