require File.dirname(__FILE__) + '/base'

class Gruff::Pie < Gruff::Base

  def draw
    @hide_line_markers = true
    
    super

    return unless @has_data

    diameter = @graph_height
    radius = @graph_height / 2.0
    top_x = @graph_left + (@graph_width - diameter) / 2.0
    center_x = @graph_left + (@graph_width / 2.0)
    center_y = @graph_top + (@graph_height / 2.0)
    total_sum = sums_for_pie()
    prev_degrees = 0.0

    @norm_data.each do |data_row|
      @d = @d.stroke current_color
      @d = @d.fill 'transparent'
      @d.stroke_width(200.0)

      current_degrees = (data_row[1][0] / total_sum) * 360.0
      #@d = @d.pie_slice(center_x, center_y, radius, 
      #                  current_percent * 100.0)
      
      #@d = @d.arc(top_x, @graph_top, 
      #            top_x + diameter, @graph_top + diameter,
      #            prev_degrees, prev_degrees + current_degrees)
      radius = 100.0
      @d = @d.ellipse(center_x, center_y, 
                  radius, radius,
                  prev_degrees, prev_degrees + current_degrees)
      
      
      prev_degrees += current_degrees
      increment_color()
    end

    @d.draw(@base_image)
  end

private

  def sums_for_pie
    total_sum = 0.0
    @norm_data.collect {|data_row| total_sum += data_row[1][0] }
    total_sum
  end

end

class Magick::Draw
  
  def pie_slice(center_x=0.0, center_y=0.0, radius=100.0, percent=0.0, rot_x=0.0)
    # Okay, this part is as confusing as hell, so pay attention:
		# This line determines the horizontal portion of the point on the circle where the X-Axis
		# should end.  It's caculated by taking the center of the on-image circle and adding that
		# to the radius multiplied by the formula for determinig the point on a unit circle that a
		# angle corresponds to.  3.6 * percent gives us that angle, but it's in degrees, so we need to
		# convert, hence the muliplication by Pi over 180
		arc_end_x = radius + (radius * Math.cos((3.6 * percent)*(Math::PI/180.0)))

		# The same goes for here, except it's the vertical point instead of the horizontal one
		arc_end_y = radius + (radius * Math.sin((3.6 * percent)*(Math::PI/180.0)))

		# Because the SVG path format is seriously screwy, we need to set the large-arc-flag to 1
		# if the angle of an arc is greater than 180 degrees.  I have no idea why this is, but it is.
		percent > 50 ? large_arc_flag = 1 : large_arc_flag = 0

		# This is also confusing
		#  M tells us to move to an absolute point on the image.  
		#   We're moving to the center of the pie
		#  h tells us to move to a relative point.  
		#   We're moving to the right edge of the circle.
		#  A tells us to start an absolute elliptical arc.  
		#   The first two values are the radii of the ellipse
		#   The third value is the x-axis-rotation (how to rotate the ellipse)
		#   The fourth value is our large-arc-flag
		#   The fifth is the sweep-flag
		#   The sixth and seventh values are the end point of the arc which we calculated previously
		# More info on the SVG path string format at: http://www.w3.org/TR/SVG/paths.html
		#
		#path = "M#{radius + 2},#{radius + 2} h#{radius} A#{radius},#{radius} #{rot_x} #{large_arc_flag},1 #{arc_end_x},#{arc_end_y} z"
		path = "M#{radius},#{radius} h#{radius} A#{radius},#{radius} #{rot_x} #{large_arc_flag},1 #{arc_end_x},#{arc_end_y} z"
    puts "PATH: #{path}"

		self.path(path)
  end
  
end