module Images
  module Tags
    module Core
      include Radiant::Taggable
      
      class TagError < StandardError; end
      
      desc %{
        The namespace for referencing images. You may specify the title
        attribute for this tag to use only images with the specified title.
      
        *Usage:* 
        <pre><code><r:images>...</r:images></code></pre>
      }
      tag 'images' do |tag|
        tag.locals.images = Helpers.current_images(tag)
        tag.expand
      end
      
      desc %{
        Expands if images exist
      }
      tag 'images:if_images' do |tag|
        tag.expand if tag.locals.images.present?
      end
      
      desc %{
        Expands unless images exist
      }
      tag 'images:unless_images' do |tag|
        tag.expand unless tag.locals.images.present?
      end
      
      desc %{
        Goes through each of the available images.
        Use the limit and offset attributes to render a specific number of images.
        Use the by and order attributes to control the order of images.
      
        *Usage:* 
        <pre><code><r:images:each [limit=0] [offset=0] [order="asc|desc"] [by="position|title|..."]>...</r:images:each></code></pre>
      }
      tag 'images:each' do |tag|
        context = ''
        Helpers.all_images_with_options(tag).each do |image|
          tag.locals.image = image
          context << tag.expand
        end
        context
      end
      
      desc %{
        Expands the current image context. 
        Images can be obtained by passing a ID, title or position attribute.
        
        *Usage:*
        <pre><code><r:image [id=] [title=""] [position=]>...</r:image></code></pre>
      }
      tag 'image' do |tag|
        tag.locals.image = Helpers.current_image(tag)
        tag.expand
      end
      
      desc %{
        Outputs the full URL of the image including the filename. 
        The style of the image can be specified by passing the style attribute.
        
        *Usage:*
        <pre><code><r:image title='image'><r:url [style="preview|original"] /></r:image></code></pre>
      }
      tag 'image:url' do |tag|
        result = nil
        if tag.locals.image ||= Helpers.current_image(tag)
          style = tag.attr['style'] || Radiant::Config['images.default'].to_sym
          result = tag.locals.image.url(style, false)
        end
        result
      end
      
      desc %{
        Outputs a very simple image tag.
        The style of the image can be specified by passing the style attribute.
        
        *Usage:*
        <pre><code><r:image title='image'><r:tag [style="preview|original"] /></r:image></code></pre>
      }
      tag 'image:tag' do |tag|
        result = nil
        if tag.locals.image ||= Helpers.current_image(tag)
          style = tag.attr['style'] || Radiant::Config['images.default'].to_sym
          result = %{<img src="#{tag.locals.image.url(style, false)}" />}
        end
        result
      end
      
      [:id, :title, :position].each do |method|
        desc %{
          Outputs the #{method} of the current image
          
          *Usage:*
          <pre><code><r:image title='image'><r:#{method} /></code></pre>
        }
        tag "image:#{method}" do |tag|
          result = nil
          if tag.locals.image ||= Helpers.current_image(tag)
            result = tag.locals.image.send(method)
          end
          result
        end
      end
      
    end
  end
end