module Prawn
  module Chart
    class Grid

      attr_accessor :width, :height, :point, :spacing, :document

      def initialize(grid_x_start, grid_y_start, grid_width, grid_height, spacing, document)
        @point = [grid_x_start, grid_y_start]
        @width = grid_width
        @height = grid_height
        @spacing = spacing
        @document = document
      end

      def start_x; @point.first; end
      def start_y; @point.last; end

      # Draws the Grid on the specified Prawn::Document
      #
      def draw
        @document.stroke_color 'CCCCCC'
        (@height / @spacing).times do |x|
          offset = @spacing * (x + 1)
          @document.move_to [@point.first, (@point.last + offset)]
          @document.line_width(0.5)
          @document.stroke_line_to([(@point.first + @width), (@point.last + offset)])
        end
        @document.move_to @point
        @document.line_width(2)
        @document.stroke_color '000000'
        @document.stroke_line_to([@point.first, @point.last + @height])
        @document.move_to @point
        @document.line_width(2)
        @document.stroke_line_to([(@point.first + @width), @point.last])
        @document.move_to @point.first, (@point.last + height)
        @document.stroke_color '000000'
        @document.line_width(1)
        @document.move_to @point
      end

    end
  end
end