module Axlsx
  # A Chart is the superclass for specific charts
  # @note Worksheet#add_chart is the recommended way to create charts for your worksheets.
  class Chart

    # The title object for the chart.
    # @return [Title]
    attr_accessor :title

    # The 3D view properties for the chart
    attr_accessor :view3D

    # A reference to the graphic frame that owns this chart
    # @return [GraphicFrame]
    attr_reader :graphic_frame

    # A collection of series objects that are applied to the chart
    # @return [SimpleTypedList]
    attr_reader :series

    # The type of series to use for this chart
    # @return [Series]
    attr_reader :series_type

    # The index of this chart in the workbooks charts collection
    # @return [Integer]
    attr_reader :index

    # The part name for this chart
    # @return [String]
    attr_reader :pn

    #TODO data labels!
    #attr_accessor :dLabls

    # The starting marker for this chart
    # @return [Marker]
    attr_reader :start_at

    # The ending marker for this chart
    # @return [Marker]
    attr_reader :end_at

    # Show the legend in the chart
    # @return [Boolean]
    attr_accessor :show_legend
   
    # Creates a new chart object
    # @param [GraphicalFrame] frame The frame that holds this chart.
    # @option options [Cell, String] title
    # @option options [Boolean] show_legend
    def initialize(frame, options={})
      @graphic_frame=frame
      @graphic_frame.anchor.drawing.worksheet.workbook.charts << self
      @series = SimpleTypedList.new Series
      @show_legend = true
      @series_type = Series
      options.each do |o|
        self.send("#{o[0]}=", o[1]) if self.respond_to? "#{o[0]}="
      end
      yield self if block_given?
    end

    def index
      @graphic_frame.anchor.drawing.worksheet.workbook.charts.index(self)
    end

    def pn
      "#{CHART_PN % (index+1)}"
    end

    def view3D=(v) DataTypeValidator.validate "#{self.class}.view3D", View3D, v; @view3D = v; end

    def title=(v) 
      v = Title.new(v) if v.is_a?(String) || v.is_a?(Cell)
      DataTypeValidator.validate "#{self.class}.title", Title, v
      @title = v
    end

    def show_legend=(v) Axlsx::validate_boolean(v); @show_legend = v; end

    # Adds a new series to the chart's series collection.
    # @return [Series]
    # @see Series
    def add_series(options={})
      @series_type.new(self, options)
      @series.last
    end

    # Chart Serialization
    # serializes the chart
    def to_xml
      builder = Nokogiri::XML::Builder.new(:encoding => ENCODING) do |xml|
        xml.send('c:chartSpace',:'xmlns:c' => XML_NS_C, :'xmlns:a' => XML_NS_A) {
          xml.send('c:chart') {
            @title.to_xml(xml) unless @title.nil?
            @view3D.to_xml(xml) unless @view3D.nil?
            xml.send('c:plotArea') {
              xml.send('c:layout')
              yield xml if block_given?
            }
            if @show_legend
              xml.send('c:legend') {
                xml.send('c:legendPos', :val => "r")
                xml.send('c:layout')
              }
            end
          }
        }
      end
      builder.to_xml
    end

    private
    
    def start_at=(v) DataTypeValidator.validate "#{self.class}.start_at", Marker, v; @start_at = v; end
    def end_at=(v) DataTypeValidator.validate "#{self.class}.end_at", Marker, v; @end_at = v; end

  end
end