require 'axle_attributes/has_attributes/json_reader'
require 'open-uri'

module AxleAttributes
  module HasAttributes
    extend ActiveSupport::Concern

    included do
      class_attribute :has_attribute_definition_class
      self.has_attribute_definition_class = '::AxleAttributes::Definition'
    end

    module ClassMethods
      def inherited(child)
        child.attribute_set = attribute_set.dup
        child.attributes = attributes.dup
        super
      end

      # Example:
      #   has_attributes(
      #     color: {type: :string, index: true, version: true},
      #     weight: {type: :integer, version: true}
      #   )
      def has_attributes(definitions, default_options = {})
        definitions.each do |name, options|
          has_attribute name, default_options.merge(options)
        end
      end

      def has_attribute(name, options = {})
        name = name.to_s
        definition = attribute_definition_class.new(self, name, options)
        add_attribute_definition(name, definition)
        definition.setup!
      end

      def add_attribute_definition(name, definition)
        attributes[name] = definition
        attribute_set << name
      end

      def has_mappings(mappings_hash)
        mappings_hash.each do |name, mappings|
          has_mapping name, mappings
        end
      end

      def has_mapping(name, mappings)
        if mappings.is_a?(Array)
          mappings = Hash[mappings.map { |v| [v, v.humanize] }]
        end

        attributes[name.to_s].mappings = mappings
      end

      def attributes_file_root
        @attributes_file_root ||= Rails.root.join('db', 'attributes')
      end

      def attributes_file_root=(pathname)
        pathname = Pathname.new(pathname) unless pathname.is_a?(Pathname)
        @attributes_file_root = pathname
      end

      def has_attributes_file(filename, options = {})
        options[:defaults] ||= {}
        options[:defaults][:filename] = filename
        AxleAttributes::HasAttributes::JsonReader.read_definitions(self, read_attributes_file(filename), options)
      end

      def attributes
        @attributes ||= {}
      end

      def attributes=(attributes)
        @attributes = attributes
      end

      def attribute_set
        @attribute_set ||= Set.new
      end

      def attribute_set=(attribute_set)
        @attribute_set = attribute_set
      end

      def attribute_definition_class
        @attribute_definition_class ||= has_attribute_definition_class.constantize
      end

      private

        def read_attributes_file(filename)
          attributes_file_pathname(filename).read
        end

        def attributes_file_pathname(filename)
          attributes_file_root.join("#{filename}.json")
        end

    end
  end
end