module ActionView #:nodoc:
  module Helpers # :nodoc:
    module SwfFuHelper
      # Returns a set of tags that display a Flash object within an
      # HTML page.
      #
      # Options:
      # * <tt>:id</tt> - the DOM +id+ of the flash +object+ element that is used to contain the Flash object; defaults to the name of the swf in +source+
      # * <tt>:width, :height</tt> - the width & height of the Flash object. Defaults to "100%". These could also specified using :size
      # * <tt>:size</tt> - the size of the Flash object, in the form "400x300".
      # * <tt>:mode</tt> - Either :dynamic (default) or :static. Refer to SWFObject's doc[http://code.google.com/p/swfobject/wiki/documentation#Should_I_use_the_static_or_dynamic_publishing_method?]
      # * <tt>:flashvars</tt> - a Hash of variables that are passed to the swf. Can also be a string like <tt>"foo=bar&hello=world"</tt>
      # * <tt>:parameters</tt> - a Hash of configuration parameters for the swf. See Adobe's doc[http://kb.adobe.com/selfservice/viewContent.do?externalId=tn_12701#optional]
      # * <tt>:alt</tt> - HTML text that is displayed when the Flash player is not available. Defaults to a "Get Flash" image pointing to Adobe Flash's installation page.
      # * <tt>:flash_version</tt> - the version of the Flash player that is required (e.g. "7" (default) or "8.1.0")
      # * <tt>:auto_install</tt> - a swf file that will upgrade flash player if needed (defaults to "expressInstall" which was installed by swf_fu)
      # * <tt>:javascript_class</tt> - specify a javascript class (e.g. "MyFlash") for your flash object. The initialize method will be called when the flash object is ready.
      # * <tt>:initialize</tt> - arguments to pass to the initialization method of your javascript class.
      # * <tt>:div_id</tt> - the DOM +id+ of the containing div itself. Defaults to <tt>"#{option[:id]}"_div</tt>
      #
      def swf_tag(source, options={}, &block)
        Generator.new(source, options, self).generate(&block)
      end

      # For compatibility with the older FlashObject.
      # It modifies the given options before calling +swf_tag+.
      # See FLASH_OBJECT.rdoc
      def flashobject_tag_for_compatibility(source, options={})
        options = options.reverse_merge(
          :auto_install     => nil,
          :parameters       => {:scale => "noscale"},
          :variables        => {:lzproxied => false},
          :flash_id         => "flashcontent_#{rand(1_100)}",
          :background_color => "#ffffff"
        )
        { :variables => :flashvars, :flash_id => :id }.each{|from, to| options[to] ||= options.delete(from) }
        options[:parameters][:bgcolor] ||= options.delete(:background_color)
        swf_tag(source, options)
      end
    
      alias_method :flashobject_tag, :flashobject_tag_for_compatibility unless defined? flashobject_tag
    
  private
      DEFAULTS = {
        :width            => "100%",
        :height           => "100%",
        :flash_version    => 7,
        :mode             => :dynamic,
        :auto_install     => "expressInstall",
        :alt    => <<-"EOS".squeeze(" ").strip.freeze
          <a href="http://www.adobe.com/go/getflashplayer">
        	  <img src="http://www.adobe.com/images/shared/download_buttons/get_flash_player.gif" alt="Get Adobe Flash player" />
          </a>
        EOS
      }.freeze
      
      class Generator # :nodoc:
        VALID_MODES = [:static, :dynamic]
        def initialize(source, options, view)
          @view = view
          @source = view.swf_path(source)
          options = ActionView::Base.swf_default_options.merge(options)
          [:html_options, :parameters, :flashvars].each do |k|
            options[k] = convert_to_hash(options[k]).reverse_merge convert_to_hash(ActionView::Base.swf_default_options[k])
          end
          options.reverse_merge!(DEFAULTS)
          options[:id] ||= source.gsub(/^.*\//, '').gsub(/\.swf$/,'')
          options[:div_id] ||= options[:id]+"_div"
          options[:width], options[:height] = options[:size].scan(/^(\d*%?)x(\d*%?)$/).first if options[:size]
          options[:auto_install] &&= @view.swf_path(options[:auto_install])
          options[:flashvars][:id] ||= options[:id]
          @mode = options.delete(:mode)
          @options = options
          unless VALID_MODES.include? @mode
            raise ArgumentError, "options[:mode] should be either #{VALID_MODES.join(' or ')}"
          end
        end

        def generate(&block)
          if block_given?
            @options[:alt] = @view.capture(&block)
            if Rails::VERSION::STRING < "2.2"
              @view.concat(send(@mode), block.binding)
            else
              @view.concat(send(@mode))
            end
          else
            send(@mode)
          end
        end
        
      private
        CONCAT = ActiveSupport.const_defined?(:SafeBuffer) ? :safe_concat : :concat
        def convert_to_hash(s)
          case s
            when Hash
              s
            when nil
              {}
            when String
              s.split("&").inject({}) do |h, kvp|
                key, value = kvp.split("=")
                h[key.to_sym] = CGI::unescape(value)
                h
              end
            else
              raise ArgumentError, "#{s} should be a Hash, a String or nil"
          end
        end
      
        def convert_to_string(h)
          h.map do |key_value|
            key_value.map{|val| CGI::escape(val.to_s)}.join("=")
          end.join("&")
        end
        
        def static
          param_list = @options[:parameters].map{|k,v| %(<param name="#{k}" value="#{v}"/>) }.join("\n")
          param_list += %(\n<param name="flashvars" value="#{convert_to_string(@options[:flashvars])}"/>) unless @options[:flashvars].empty?
          html_options = @options[:html_options].map{|k,v| %(#{k}="#{v}")}.join(" ")
          r = @view.javascript_tag(
            %(swfobject.registerObject("#{@options[:id]}_container", "#{@options[:flash_version]}", #{@options[:auto_install].to_json});)
          )
          r.send CONCAT, <<-"EOS".strip
            <div id="#{@options[:div_id]}"><object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="#{@options[:width]}" height="#{@options[:height]}" id="#{@options[:id]}_container" #{html_options}>
              <param name="movie" value="#{@source}" />
              #{param_list}
              <!--[if !IE]>-->
              <object type="application/x-shockwave-flash" data="#{@source}" width="#{@options[:width]}" height="#{@options[:height]}" id="#{@options[:id]}">
              #{param_list}
              <!--<![endif]-->
                #{@options[:alt]}
              <!--[if !IE]>-->
              </object>
              <!--<![endif]-->
            </object></div>
          EOS
          r << @view.javascript_tag(extend_js) if @options[:javascript_class]
          r.send CONCAT, library_check
          r
        end
      
        def dynamic
          @options[:html_options] = @options[:html_options].merge(:id => @options[:id])
          @options[:parameters] = @options[:parameters].dup # don't modify the original parameters
          args = (([@source] + @options.values_at(:div_id,:width,:height,:flash_version)).map(&:to_s) + 
                  @options.values_at(:auto_install,:flashvars,:parameters,:html_options)
                 ).map(&:to_json).join(",")
          preambule = @options[:switch_off_auto_hide_show] ? "swfobject.switchOffAutoHideShow();" : ""
          r = @view.javascript_tag(preambule + "swfobject.embedSWF(#{args})") 
          r.send CONCAT, <<-"EOS".strip
            <div id="#{@options[:div_id]}">
              #{@options[:alt]}
            </div>
          EOS
          r << @view.javascript_tag("swfobject.addDomLoadEvent(function(){#{extend_js}})") if @options[:javascript_class]
          r.send CONCAT, library_check
          r
        end
      
        def extend_js
          arglist = case
          when @options[:initialize].instance_of?(Array) 
            @options[:initialize].map(&:to_json).join(",")
          when @options.has_key?(:initialize)
            @options[:initialize].to_json
          else
            ""
          end
          "Object.extend($('#{@options[:id]}'), #{@options[:javascript_class]}.prototype).initialize(#{arglist})"
        end
      
        def library_check
          return "" unless 'development' == ENV['RAILS_ENV']
          @view.javascript_tag(<<-"EOS")
            if (typeof swfobject == 'undefined') {
              document.getElementById('#{@options[:div_id]}').innerHTML = '<strong>Warning:</strong> SWFObject.js was not loaded properly. Make sure you <tt>&lt;%= javascript_include_tag :defaults %&gt;</tt> or <tt>&lt;%= javascript_include_tag :swfobject %&gt;</tt>';
            }
          EOS
        end
      end #class Generator
    end
  end
end