module PictureTag
  # This is a little module to hold logic that doesn't fit other places. If it
  # starts getting big, refactor.
  module Utils
    # These are valid ImageMagick gravity arguments (relevant to our use
    # case):
    GRAVITIES =
      %w[center
         north
         northeast
         east
         southeast
         south
         southwest
         west
         northwest].freeze

    # This is an attempt to recognize valid imagemagick geometry arguments
    # with regex. It only tries to match values which don't preserve aspect
    # ratio, as they're the ones people might actually need here.
    GEOMETRY_REGEX = /\A\d*%?[x:]?\d*[%!]?([+-]\d+){,2}\Z/i.freeze

    class << self
      # Configure Jekyll to keep our generated files
      def keep_files
        dest_dir = PictureTag.config['picture']['output']

        # Chop a slash off the end, if it's there. Doesn't work otherwise.
        dest_dir = dest_dir[0..-2] if dest_dir =~ %r{/\z}

        return if PictureTag.site.config['keep_files'].include?(dest_dir)

        PictureTag.site.config['keep_files'] << dest_dir
      end

      # Print a warning to the console
      def warning(message)
        return if PictureTag.config['picture']['suppress_warnings']

        warn 'Jekyll Picture Tag Warning: '.yellow + message
      end

      # Parse a liquid template; allows liquid variables to be included as tag
      # params.
      def liquid_lookup(params)
        Liquid::Template.parse(params).render(PictureTag.context)
      end

      # Used for auto markup configuration and such
      def count_srcsets
        PictureTag.formats.length * PictureTag.source_images.length
      end

      # Returns whether or not the current page is a markdown file.
      def markdown_page?
        page_name = PictureTag.page['name']
        page_ext = PictureTag.page['ext']
        ext = page_ext || File.extname(page_name)

        ext.casecmp('.md').zero? || ext.casecmp('.markdown').zero?
      end

      def titleize(input)
        input.split('_').map(&:capitalize).join
      end
    end
  end
end