module ActionView::Helpers::AssetTagHelper

def audio_tag(*sources)
  multiple_sources_tag('audio', sources)
end

def auto_discovery_link_tag(type = :rss, url_options = {}, tag_options = {})
  if !(type == :rss || type == :atom) && tag_options[:type].blank?
    raise ArgumentError.new("You should pass :type tag_option key explicitly, because you have passed #{type} type other than :rss or :atom.")
  end
  tag(
    "link",
    "rel"   => tag_options[:rel] || "alternate",
    "type"  => tag_options[:type] || Mime::Type.lookup_by_extension(type.to_s).to_s,
    "title" => tag_options[:title] || type.to_s.upcase,
    "href"  => url_options.is_a?(Hash) ? url_for(url_options.merge(:only_path => false)) : url_options
  )
end

def extract_dimensions(size)
  if size =~ %r{\A\d+x\d+\z}
    size.split('x')
  elsif size =~ %r{\A\d+\z}
    [size, size]
  end
end

def favicon_link_tag(source='favicon.ico', options={})
  tag('link', {
    :rel  => 'shortcut icon',
    :type => 'image/x-icon',
    :href => path_to_image(source)
  }.merge!(options.symbolize_keys))
end

def image_alt(src)
  File.basename(src, '.*').sub(/-[[:xdigit:]]{32,64}\z/, '').tr('-_', ' ').capitalize
end

def image_tag(source, options={})

# =>
image_tag("/icons/icon.gif", class: "menu_icon")
# =>
image_tag("/icons/icon.gif", height: '32', width: '32')
# =>
image_tag("/icons/icon.gif", size: "16")
# =>
image_tag("icon.png", size: "16x10", alt: "Edit Entry")
# =>
image_tag("icon.png")
# =>
image_tag("icon")

==== Examples

:size will be ignored if the value is not in the correct format.
width="30" and height="45", and "50" becomes width="50" and height="50".
* :size - Supplied as "{Width}x{Height}" or "{Number}", so "30x45" becomes
+source+ is used (capitalized and without the extension)
* :alt - If no alt text is given, the file name part of the

two additional keys for convenience and conformance:
You can add HTML attributes using the +options+. The +options+ supports

==== Options

path or a file.
Returns an HTML image tag for the +source+. The +source+ can be a full

def image_tag(source, options={})
  options = options.symbolize_keys
  src = options[:src] = path_to_image(source)
  unless src =~ /^(?:cid|data):/ || src.blank?
    options[:alt] = options.fetch(:alt){ image_alt(src) }
  end
  options[:width], options[:height] = extract_dimensions(options.delete(:size)) if options[:size]
  tag("img", options)
end

def javascript_include_tag(*sources)
  options = sources.extract_options!.stringify_keys
  path_options = options.extract!('protocol', 'extname').symbolize_keys
  sources.uniq.map { |source|
    tag_options = {
      "src" => path_to_javascript(source, path_options)
    }.merge!(options)
    content_tag(:script, "", tag_options)
  }.join("\n").html_safe
end

def multiple_sources_tag(type, sources)
  options = sources.extract_options!.symbolize_keys
  sources.flatten!
  yield options if block_given?
  if sources.size > 1
    content_tag(type, options) do
      safe_join sources.map { |source| tag("source", :src => send("path_to_#{type}", source)) }
    end
  else
    options[:src] = send("path_to_#{type}", sources.first)
    content_tag(type, nil, options)
  end
end

def stylesheet_link_tag(*sources)
  options = sources.extract_options!.stringify_keys
  path_options = options.extract!('protocol').symbolize_keys
  sources.uniq.map { |source|
    tag_options = {
      "rel" => "stylesheet",
      "media" => "screen",
      "href" => path_to_stylesheet(source, path_options)
    }.merge!(options)
    tag(:link, tag_options)
  }.join("\n").html_safe
end

def video_tag(*sources)
  multiple_sources_tag('video', sources) do |options|
    options[:poster] = path_to_image(options[:poster]) if options[:poster]
    options[:width], options[:height] = extract_dimensions(options.delete(:size)) if options[:size]
  end
end