##   RSence
 #   Copyright 2009 Riassence Inc.
 #   http://riassence.com/
 #
 #   You should have received a copy of the GNU General Public License along
 #   with this software package. If not, contact licensing@riassence.com
 ##


module RSence
  
  
  module Plugins
    
    
    # This class automatically loads a YAML file from "gui" subdirectory of a plugin.
    #
    # Extend your plugin from the {GUIPlugin__ GUIPlugin} class instead of the Plugin class to make this work automatically.
    #
    # @example Initialize like this from inside a plugin method. This will load the "gui/my_gui.yaml" file.
    #   gui = GUIParser.new( self, 'my_gui' )
    #
    # @example To make the client render the contents of the yaml do this:
    #   ses = get_ses( msg )
    #   params = { :values => @gui.values( ses ) }
    #   gui.init( msg, params )
    class GUIParser
      
      # include ::RSence
      
      # Use this method to send the client all commands required to construct the GUI Tree using JSONRenderer.
      # @param [Message] msg The +Message+ instance +msg+ used all over the place.
      # @param [Hash] params Containing all parameters referred from the YAML file, see: {GUIPlugin__#gui_params GUIPlugin#gui_params}
      def init( msg, params )
        gui_data = YAML.load( @yaml_src )
        parse_gui( gui_data, params )
        if gui_data.has_key?('dependencies')
          @parent.include_js( msg, gui_data['dependencies'] )
          gui_data.delete('dependencies')
        end
        if gui_data.has_key?('include')
          gui_data['include'].each do | js_file |
            js_src = @parent.read_js_once( msg, js_file )
            msg.reply( js_src )
          end
        end
        gui_name = @parent.name
        json_data = JSON.dump( gui_data )
        msg.reply( "JSONRenderer.nu(#{json_data});", true )
      end
      
      # Use this method to extract all the value id's of the +ses+ hash.
      def values( ses )
        ids = {}
        ses.each do | key, value |
          if value.class == HValue
            ids[ key ] = value.value_id
          end
        end
        return ids
      end
      
    private
      
      def json_fun( value )
        JSON.parse( "[#{value}]" ).first
      end
      
      # Parses the gui data using params. Called from +init+.
      def parse_gui( gui_data, params )
        data_class = gui_data.class
        if data_class == Array
          gui_data.each_with_index do | item, i |
            gui_data[i] = parse_gui( item, params )
          end
        elsif data_class == Hash
          gui_data.each do | key, value |
            gui_data[key] = parse_gui( value, params )
          end
        elsif data_class == Symbol
          sym_str = gui_data.to_s
          if sym_str.include? '.'
            sym_arr = sym_str.split('.')
          else
            sym_arr = [ sym_str ]
          end
          return get_params( sym_arr, params )
        elsif data_class == String and gui_data.strip.start_with?('function(')
          return @parent.plugins[:client_pkg].squeeze( "a="+json_fun( gui_data.to_json ) )[2..-1]
        end
        return gui_data
      end
      
      # Searches the params hash for parameters whenever encountered a Symbol in the YAML.
      def get_params( params_path, params )
        item = params_path.shift
        if params.class == Hash
          has_str = params.has_key?( item )
          has_sym = params.has_key?( item.to_sym )
          item = item.to_sym if has_sym
          if has_str or has_sym
            if params_path.size == 0
              return params[item]
            else
              return get_params( params_path, params[ item ] )
            end
          end
        end
        return ''
      end
      
      # Loads the YAML file.
      # = Parameters
      # +parent+::    The Plugin instance called from, use +self+ when constructing in a Plugin method.
      # +yaml_src+::  The YAML source template for the GUI
      def initialize( parent, yaml_src )
        @parent = parent
        @yaml_src = yaml_src
      end
      
    end
  end
end