module Crystal
  module BasicHtmlHelper
    BOOLEAN_ATTRIBUTES = %w(disabled readonly multiple checked autobuffer
                         autoplay controls loop selected hidden scoped async
                         defer reversed ismap seemless muted required
                         autofocus novalidate formnovalidate open).to_set
    BOOLEAN_ATTRIBUTES.merge(BOOLEAN_ATTRIBUTES.map {|attr| attr.to_sym })
    
    
    # 
    # authenticity_token
    # 
    def authenticity_token; workspace.request.session['authenticity_token'] end    
    
    
    # 
    # JavaScript & StyleSheets
    #     
    def stylesheet_link_tag *stylesheets
      Array(stylesheets).collect{|ssheet|
        tag :link, '', :href => "#{config && config.url_root!}#{ssheet}", :media => "screen", :rel => "stylesheet", :type => "text/css"
      }.join("\n")
    end
    
    
    # 
    # Assets
    # 
    def image_tag src, opt = {}
      opt[:src] = src
      tag :img, '', opt
    end
            
    
    # 
    # Common HTML tags
    # 
    def label_tag name, text, options = {}
      tag :label, text, options.merge(:for => name)
    end
    
    
    # 
    # Special
    # 
    def tag name, content_or_options_with_block = nil, options = nil, escape = true, &block      
      if block_given?
        options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)
        content = capture(&block)
        concat "<#{name}#{tag_options(options)}>#{content}</#{name}>"
      else
        content = content_or_options_with_block
        "<#{name}#{tag_options(options)}>#{content}</#{name}>"
      end      
    end
    
    # instance_methods(false).each do |m|
    #   alias_method "html_#{m}", m
    # end
    
    # Escape
    def h obj; obj.to_s.html_escape end    
    
    protected
    
      def tag_options options
        return "" unless options
        options.must_be.a Hash
        unless options.blank?
          attrs = []
          options.each_pair do |key, value|
            if BOOLEAN_ATTRIBUTES.include?(key)
              attrs << %(#{key}="#{key}") if value
            elsif !value.nil?
              final_value = value.is_a?(Array) ? value.join(" ") : value
              attrs << %(#{key}="#{final_value}")
            end
          end
          " #{attrs.sort * ' '}" unless attrs.empty?
        end
      end
  end
end