/ OPTIONS PROCESSING
/ hide slides on %conceal, %notitle and named "!"
- titleless = (title = self.title) == '!'
- hide_title = (titleless || (option? :notitle) || (option? :conceal))

- vertical_slides = find_by(context: :section) {|section| section.level == 2 }

/ extracting block image attributes to find an image to use as a
/ background_image attribute
- data_background_image, data_background_size, data_background_repeat,
  data_background_position, data_background_transition = nil

/ process the first image block in the current section that acts as a background
- section_images = blocks.map do |block|
  - if (ctx = block.context) == :image
    - ['background', 'canvas'].include?(block.attributes[1]) ? block : []
  - elsif ctx == :section
    - []
  - else
    - block.find_by(context: :image) {|image| ['background', 'canvas'].include?(image.attributes[1]) } || []
- if (bg_image = section_images.flatten.first)
  - data_background_image = image_uri(bg_image.attr 'target')
  / make sure no crash on nil and default values make sense
  - data_background_size = bg_image.attr 'size'
  - data_background_repeat = bg_image.attr 'repeat'
  - data_background_transition = bg_image.attr 'transition'
  - data_background_position = bg_image.attr 'position'

/ background-image section attribute overrides the image one
- if attr? 'background-image'
  - data_background_image = image_uri(attr 'background-image')

- if attr? 'background-video'
  - data_background_video = media_uri(attr 'background-video')

- if attr? 'background-color'
  - data_background_color = attr 'background-color'

- parent_section_with_vertical_slides = @level == 1 && !vertical_slides.empty?

- content_for :footnotes
  - slide_footnotes = slide_footnotes(self)
  - if document.footnotes? && !(parent.attr? 'nofootnotes') && !slide_footnotes.empty?
    .footnotes
      - slide_footnotes.each do |footnote|
        .footnote
          = "#{footnote.index}. #{footnote.text}"

- content_for :section
  section(id=(titleless ? nil : id)
    class=roles
    data-transition=(attr 'transition')
    data-transition-speed=(attr 'transition-speed')
    data-background-color=data_background_color
    data-background-image=data_background_image
    data-background-size=(data_background_size || attr('background-size'))
    data-background-repeat=(data_background_repeat || attr('background-repeat'))
    data-background-transition=(data_background_transition || attr('background-transition'))
    data-background-position=(data_background_position || attr('background-position'))
    data-background-iframe=(attr "background-iframe")
    data-background-video=data_background_video
    data-background-video-loop=((attr? 'background-video-loop') || (option? 'loop'))
    data-background-video-muted=((attr? 'background-video-muted') || (option? 'muted'))
    data-background-opacity=(attr "background-opacity")
    data-autoslide=(attr "autoslide")
    data-state=(attr 'state')
    data-auto-animate=((attr? 'auto-animate') || (option? 'auto-animate'))
    data-auto-animate-easing=((attr 'auto-animate-easing') || (option? 'auto-animate-easing'))
    data-auto-animate-unmatched=((attr 'auto-animate-unmatched') || (option? 'auto-animate-unmatched'))
    data-auto-animate-duration=((attr 'auto-animate-duration') || (option? 'auto-animate-duration'))
    data-auto-animate-id=(attr 'auto-animate-id')
    data-auto-animate-restart=((attr? 'auto-animate-restart') || (option? 'auto-animate-restart')))
    - unless hide_title
      h2=section_title
    - if parent_section_with_vertical_slides
      - unless (_blocks = blocks - vertical_slides).empty?
        div.slide-content
          - _blocks.each do |block|
            =block.convert
      - yield_content :footnotes

    - else
      - unless (_content = content.chomp).empty?
        div.slide-content
          =_content
      - yield_content :footnotes

    - clear_slide_footnotes

/ RENDERING
/ render parent section of vertical slides set
- if parent_section_with_vertical_slides
  section
    - yield_content :section
    - vertical_slides.each do |subsection|
      =subsection.convert

/ render standalone slides (or vertical slide subsection)
- else
  - if @level >= 3
    / dynamic tags which maps <hX> with level
    h level=(@level) =title
    =content.chomp
  - else
    - yield_content :section