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) - 10 # Move graph up a bit
    total_sum = sums_for_pie()
    prev_degrees = 0.0

    # Use full data since we can easily calculate percentages
    @data.each do |data_row|
      if data_row[1][0] > 0
        @d = @d.stroke data_row[DATA_COLOR_INDEX]
        @d = @d.fill 'transparent'
        @d.stroke_width(200.0)

        current_degrees = (data_row[1][0] / total_sum) * 360.0 
        radius = 100.0
        @d = @d.ellipse(center_x, center_y, 
                  radius, radius,
                  prev_degrees, prev_degrees + current_degrees + 0.5) # <= +0.5 'fudge factor' gets rid of the ugly gaps
                  
        half_angle = prev_degrees + ((prev_degrees + current_degrees) - prev_degrees) / 2
      

        @d = draw_label(center_x,center_y, 
                    half_angle, 
                    radius, 
                    ((data_row[1][0] / total_sum) * 100).round.to_s + '%     ')
      
        prev_degrees += current_degrees
      end
    end

    @d.draw(@base_image)
  end

private

  def draw_label(center_x, center_y, angle, radius, amount)
    r_offset = 130      # The distance out from the center of the pie to get point
    x_offset = center_x + 15 # The label points need to be tweaked slightly
    y_offset = center_y + 0  # This one doesn't though
    x = x_offset + ((radius + r_offset) * Math.cos(angle.deg2rad))
    y = y_offset + ((radius + r_offset) * Math.sin(angle.deg2rad))
    
    # Draw label
    @d.fill = @marker_color
    @d.font = @font if @font
    @d.pointsize = scale_fontsize(20)
    @d.stroke = 'transparent'
    @d.font_weight = BoldWeight
    @d.gravity = CenterGravity
    @d.annotate_scaled( @base_image, 
                      0, 0,
                      x, y, 
                      amount, @scale)
  end

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

end


class Float
  # Used for degree => radian conversions
  def deg2rad
    self * (Math::PI/180.0)
  end
end

# From sparklines...not currently used
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