# XMLToolKit - TkXML
# Copyright (c) 2002 Thomas Sawyer, LGPL
#
# Version: April 2002 - Alpha (2.04a)
#
# A combination of Ruby/Tk + REXML 
# to allow for fast and easy creation
# of Tk interfaces using standard XML

# XMLToolKit is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# XMLToolKit is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with XMLToolKit; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA


require 'rexml/document'
require 'tk'

module XMLToolKit

  class TkXML
  
    def initialize(source)
      @listener = TkXML_Listener.new
      REXML::Document.parse_stream(source, @listener)
    end
  
    def build
      Tk.mainloop
    end
  
  end
  
  class TkXML_Listener
  
    def initialize
      puts "Initializing TkXML_Listner"
      @widget = Hash.new
      @widget_stack = Array.new
      @parent = nil
    end
  
    def tag_start name, attributes
      
      # get parent, the widget on the bottom of the stack
      @parent = @widget_stack.last
      
      # pull off the tag name if prefixed with the Tk namespace
      if name[0..2] == "Tk:"
        tag_name = name[3..name.length]
      else
        tag_name = name
      end
      
      # looks life the attributes object given is nothing morethen a array in an array. how lame!
      # this wll turn it into a hash
      attr_hash = Hash.new
      attributes.each do |a|
        attr_hash[a[0]] = a[1]
      end
      
      # okay, lets do this thing
      
      # is it a method call or a new widget?
      if tag_name[0..0] == '_'
      
        # apply method
        puts "Applying Method: #{name} to #{@parent}"
        
        # get method name
        meth_name = tag_name[1..tag_name.length]
        
        # assign the method's parameters
        p_arr = Array.new	# array for parameters to be passed
        p_init = Hash.new	# for the ordered arguments _1 _2 etc.
        p_hash = Hash.new	# for all other named parameters
        
        # weed out the ordered parameters from the hash parameters
        attr_hash.each do |n, v|
          puts "   #{n} => #{v}"
          if n[0..0] == "_"
            p_init[n] = v
          else
            p_hash[n] = v
          end
        end
  
        # sort the ordered parameters based on the hash key
        # note: this converts p_init into an associative array
        # then place each one in the parameter array
        if not p_init.empty?
          p_init.sort
          p_init.each do |a|
            p_arr.push a[1]
          end
        end
        
        # now add the hash to the array if there is one
        if not p_hash.empty?
          p_arr.push p_hash
        end
        
        # call the method
        @parent.send(meth_name, *p_arr)
      
      else
  
        # create widget
        puts "Creating Widget: #{name} of #{@parent}"
  
        widget_class = "Tk" + tag_name.capitalize
        widget_name = attr_hash['name']
  
        if @parent == nil
          @widget[widget_name] = Tk.const_get(widget_class).new
        else
          @widget[widget_name] = Tk.const_get(widget_class).new(@parent)
        end
        
        # assign the widget properties
        attr_hash.each do |n, v|
          if not n == 'name'
            puts "   #{n} => #{v}"
            @widget[widget_name].send(n, v)
          end
        end
  
        # push widget on to the stack
        @widget_stack.push(@widget[widget_name])
      
      end
    
    end
  
  
    def tag_end name
    
      # pull off the tag name if prefixed with the Tk namespace
      if name[0..2] == "Tk:"
        tag_name = name[3..name.length]
      else
        tag_name = name
      end
      
      # if method then we're finish
      # else if widget then finish creation and pop off the widget stack
      if tag_name[0..0] == "_"
      
        puts "End Method: #{name}"
      
      else
      
        @parent = @widget_stack[-2]
        current = @widget_stack.last
        
        case tag_name.downcase
          when "menu"
            @parent.menu(current)
        end
        
        # pop current widget off of stack
        @widget_stack.pop
        
        puts "End Widget: #{name}"
        
      end
      
    end
  
    
    def text free_radical
      if not free_radical.strip == ""
        puts "Error: TkXML does not use XML text entries: #{free_radical}"
      end
    end
  
  end

end  # XMLToolKit