# new gruff graph type added to enable sideways stacking bar charts (basically looks like a x/y
# flip of a standard stacking bar chart)
#
# alun.eyre@googlemail.com 
#
require File.dirname(__FILE__) + '/base'

class Gruff::SideStackedBar < Gruff::Base

    # instead of base class version, draws vertical background lines and label
    def draw_line_markers

      return if @hide_line_markers

      # Draw horizontal line markers and annotate with numbers
      @d = @d.stroke(@marker_color)
      @d = @d.stroke_width 1
      number_of_lines = 5

      # TODO Round maximum marker value to a round number like 100, 0.1, 0.5, etc.
      increment = significant(@maximum_value.to_f / number_of_lines)
      (0..number_of_lines).each do |index|

        line_diff = (@graph_right - @graph_left) / number_of_lines
        x = @graph_right - (line_diff * index) - 1
        @d = @d.line(x, @graph_bottom, x, @graph_top)

        diff = index - number_of_lines
        marker_label = diff.abs * increment

        @d.fill = @marker_color
        @d.font = @font
        @d.stroke = 'transparent'
        @d.pointsize = scale_fontsize(@marker_pointsize)
#        @d.gravity = NorthGravity
        @d = @d.annotate_scaled( @base_image, 
                          100, 20,
                          x - (@marker_pointsize/1.5), @graph_bottom + 40, 
                          marker_label.to_s, @scale)

      end
    end

    # instead of base class version, modified to enable us to draw on the Y axis instead of X
    def draw_label(y_offset, index)
      if !@labels[index].nil? && @labels_seen[index].nil?
        @d.fill = @marker_color
        @d.font = @font
        @d.stroke = 'transparent'
        @d.font_weight = NormalWeight
        @d.pointsize = scale_fontsize(@marker_pointsize)
        @d.gravity = CenterGravity
        @d = @d.annotate_scaled(@base_image,
                                1, 1,
                                @graph_left / 2, y_offset,
                                @labels[index], @scale)
        @labels_seen[index] = 1
      end
    end

    def draw
      super

      return unless @has_data

      # Setup spacing.
      #
      # Columns sit stacked.
      spacing_factor = 0.9

      @bar_width = @graph_height / @column_count.to_f
      @d = @d.stroke_opacity 0.0
      height = Array.new(@column_count, 0)
      length = Array.new(@column_count, @graph_left)

      @norm_data.each_with_index do |data_row, row_index|
        @d = @d.fill data_row[DATA_COLOR_INDEX]

        data_row[1].each_with_index do |data_point, point_index|

	  ## using the original calcs from the stacked bar chart to get the difference between
	  ## part of the bart chart we wish to stack.
	  temp1 = @graph_left + (@graph_width -
                                data_point * @graph_width - 
                                height[point_index]) + 1
	  temp2 = @graph_left + @graph_width - height[point_index] - 1
	  difference = temp2 - temp1

	  left_x = length[point_index] #+ 1
          left_y = @graph_top + (@bar_width * point_index)
	  right_x = left_x + difference
          right_y = left_y + @bar_width * spacing_factor
	  length[point_index] += difference
          height[point_index] += (data_point * @graph_width - 2)

          @d = @d.rectangle(left_x, left_y, right_x, right_y)

          # Calculate center based on bar_width and current row
          label_center = @graph_top + (@bar_width * point_index) + (@bar_width * spacing_factor / 2.0)
          draw_label(label_center, point_index)
        end

      end

      @d.draw(@base_image)    
    end

    protected

    def larger_than_max?(data_point, index=0)
      max(data_point, index) > @maximum_value
    end

    def max(data_point, index)
      @data.inject(0) {|sum, item| sum + item[1][index]}
    end

end