module Polygon
  class Database < Alf::Environment

    attr_reader :root, :options

    def initialize(root, options = {})
      @root    = Path(root)
      @options = default_options.merge(options)
    end

    def default_options
      { :extensions => ["yml", "md"] }
    end

    def dataset(name)
      if self.respond_to?(name)
        send(name)
      else
        raise Alf::NoSuchDatasetError, "No such dataset `#{name}`"
      end
    end

    def entries
      @entries ||= Entries.new(root, options)
    end

    def sitemap
      @sitemap ||= begin
        Alf.lispy(self).compile do
          (extend :entries,
                  :path    => lambda{ entry.relative_path.to_url            },
                  :lastmod => lambda{ entry.path.mtime.strftime("%Y-%m-%d") })
        end
      end
    end

    class Entries
      include Alf::Iterator

      def initialize(root, options)
        @root    = root
        @options = options
      end

      def each
        extensions = @options[:extensions]
        @root.glob("**/*").each do |file|
          next unless file.file? and extensions.include?(file.ext)
          entry = Entry.new(@root, file % @root)
          yield(:entry => entry)
        end
      end

    end # class Entries

  end # class Database
end # class Polygon