module Middleman
  module CoreExtensions
    # Load helpers in `helpers/`
    class ExternalHelpers < Extension
      def initialize(app, options_hash={}, &block)
        super

        # Setup a default helpers paths
        app.config.define_setting :helpers_dir, 'helpers', 'Directory to autoload helper modules from'
        app.config.define_setting :helpers_filename_glob, '**.rb', 'Glob pattern for matching helper ruby files'
        app.config.define_setting :helpers_filename_to_module_name_proc, proc { |filename|
          basename = File.basename(filename, File.extname(filename))
          basename.camelcase
        }, 'Proc implementing the conversion from helper filename to module name'
      end

      def after_configuration
        helpers_path = File.join(app.root, app.config[:helpers_dir])

        return unless File.exist?(helpers_path)

        Dir[File.join(helpers_path, app.config[:helpers_filename_glob])].each do |filename|
          module_name = app.config[:helpers_filename_to_module_name_proc].call(filename)
          next unless module_name

          require filename
          next unless Object.const_defined?(module_name.to_sym)

          app.template_context_class.send :include, Object.const_get(module_name.to_sym)
        end
      end
    end
  end
end