module Tk
  module Tile
    def self.style(style, parent_name)
      [style, parent_name.to_s.split('::').last].join('.')
    end

    module Style
      extend Tk::Cget, Tk::Configure
      TkkStyleCmd = 'ttk::style'.freeze

      # Returns a list of all known themes.
      def self.theme_names
        Tk.execute('ttk::style', 'theme', 'names')
      end

      # Sets the current theme to themeName, and refreshes all widgets.
      def self.theme_use(name)
        return unless theme_names.include? name
        Tk.execute_only('ttk::style', 'theme', 'use', name) && name
      end

      # Temporarily sets the current theme to themeName, evaluate script,
      # then restore the previous theme. Typically script simply defines
      # styles and elements, though arbitrary Tcl code may appear.
      def self.theme_settings(name, &block)
        return unless block
        raise ArgumentError unless theme_names.include? name

        id = Tk.uuid(:proc){|uuid| Tk.callbacks[uuid] = block }
        cmd = "{ RubyFFI::callback #{id} }"
        Tk.eval "ttk::style theme settings #{name} #{cmd}"
        #Tk.execute_only('ttk::style', 'theme', 'settings', name, cmd)
        Tk.callbacks.delete(id) if id
        name
      end

      # Creates a new theme. It is an error if themeName already exists.
      # If -parent is specified, the new theme will inherit styles, elements, and
      # layouts from the parent theme basedon. If -settings is present, script is
      # evaluated in the context of the new theme as per ttk::style theme settings.
      def self.theme_create(name, options={}, &block)
        raise ArgumentError if theme_names.include? name
        options = options.to_tcl_options

        if block
          id = Tk.uuid(:proc){|uuid| Tk.callbacks[uuid] = block }
          options << " -settings { RubyFFI::callback #{id} }"
        end
        res = Tk.execute_only('ttk::style', 'theme', 'create', name, options)
        Tk.callbacks.delete(id) if id
        res
      end


      # Returns the list of elements defined in the current theme.
      def self.element_names
        Tk.execute('ttk::style', 'element', 'names')
      end

      # Returns the list of element's options.
      def self.element_options(name)
        return unless element_names.include? name
        Tk.execute('ttk::style', 'element', 'options', name).to_a
      end

      # Creates a new element in the current theme of type type. The only
      # built-in element type is image (see ttk_image(n)), although themes
      # may define other element types (see Ttk_RegisterElementFactory).
      def self.element_create(name, type, args=nil, options={})
        if type == 'image' || type == :image
          Tk.execute_only('ttk::style', 'element', 'create', name, 'image', args, options.to_tcl_options)
        else
          #Tk.execute_only('ttk::style', 'element', 'create', name, type)
        end
      end


      # Define the widget layout for style style. See LAYOUTS below for the format
      # of layoutSpec. If layoutSpec is omitted, return the layout specification
      # for style style.
      def self.layout(name, layout_spec)
        Tk.execute_only('ttk::style', 'layout', name, layout_spec)
      end

      # Sets dynamic values of the specified option(s) in style.
      # Each statespec / value pair is examined in order; the value
      # corresponding to the first matching statespec is used.
      def self.map(style, options={})
        style.kind_of?(Hash) && (options, style = style, nil)
        style = '.' unless style

        Tk.execute_only('ttk::style', 'map', style, options.to_tcl_options )
      end

      # Sets the default value of the specified option(s) in style.
      def self.configure(style=nil, options={})
        style.kind_of?(Hash) && (keys, style = style, nil)
        style = '.' unless style

        Tk.execute_only('ttk::style','configure', style, options.to_tcl_options)
      end

      # Returns the value specified for -option in style style in state
      # state, using the standard lookup rules for element options.
      # state is a list of state names; if omitted, it defaults to all
      # bits off (the “normal” state). If the default argument is present,
      # it is used as a fallback value in case no specification
      # for -option is found.
      def self.lookup(style, option, state=Tk::None, default=Tk::None)
        Tk.execute('ttk::style', 'lookup', style, option.to_tcl_option, state, default).to_s
      end
    end
  end
end