module JsDuck
  module Render

    # Generates HTML for the class hierarchy sidebar inside class
    # documentation.
    class Sidebar
      def initialize(opts)
        @opts = opts
      end

      # Renders a sidebar for given class.
      # Returns Array of HTML or nil.
      def render(cls)
        items = [
          render_alternate_class_names(cls[:alternateClassNames]),
          render_tree(cls),
          render_dependencies(cls[:mixins], "Mixins"),
          render_dependencies(cls[:parentMixins], "Inherited mixins"),
          render_dependencies(cls[:requires], "Requires"),
          render_dependencies(cls[:subclasses], "Subclasses"),
          render_dependencies(cls[:mixedInto], "Mixed into"),
          render_dependencies(cls[:uses], "Uses"),
          render_files(cls[:files])
        ]

        if items.compact.length > 0
          return ['<pre class="hierarchy">', items, '</pre>']
        else
          return nil
        end
      end

      private

      def render_alternate_class_names(names)
        return if names.length == 0

        return [
          "<h4>Alternate names</h4>",
          names.map {|name| "<div class='alternate-class-name'>#{name}</div>" },
        ]
      end

      def render_dependencies(names, title)
        return if !names || names.length == 0

        return [
          "<h4>#{title}</h4>",
          names.map {|name| "<div class='dependency'>#{name.exists? ? render_link(name) : name}</div>" },
        ]
      end

      def render_files(files)
        return if !@opts.source || files.length == 0 || files[0][:filename] == ""

        return [
          "<h4>Files</h4>",
          files.map do |file|
            url = "source/" + file[:href]
            title = File.basename(file[:filename])
            "<div class='dependency'><a href='#{url}' target='_blank'>#{title}</a></div>"
          end
        ]
      end

      # Take care of the special case where class has parent for which we have no docs.
      # In that case the "extends" property exists but "superclasses" is empty.
      # We still create the tree, but without links in it.
      def render_tree(cls)
        return if !cls[:extends] || cls[:extends] == "Object"

        return [
          "<h4>Hierarchy</h4>",
          render_class_tree(cls[:superclasses] + [cls[:name]])
        ]
      end

      def render_class_tree(classes, i=0)
        return "" if classes.length <= i

        name = classes[i]
        return [
          "<div class='subclass #{i == 0 ? 'first-child' : ''}'>",
            classes.length-1 == i ? "<strong>#{name}</strong>" : (name.exists? ? render_link(name) : name),
            render_class_tree(classes, i+1),
          "</div>",
        ]
      end

      def render_link(cls_name)
        "<a href='#!/api/#{cls_name}' rel='#{cls_name}' class='docClass'>#{cls_name}</a>"
      end

    end

  end
end