module Rubyvis
  module SvgScene
    def self.area(scenes)
      e = scenes._g.elements[1]
      return e if scenes.size==0
      s=scenes[0]
      # segmented */
      return self.area_segment(scenes) if (s.segmented) 
      # visible
      # 
      return e if (!s.visible)
      
      fill = s.fill_style
      stroke = s.stroke_style
      
      return e if (fill.opacity==0 and stroke.opacity==0) 
      # /** @private Computes the straight path for the range [i, j]. */
      path=lambda {|ii,j|
        p1 = []
        p2 = [];
        k=j
        (ii..k).each {|i|
          si = scenes[i]
          sj = scenes[j]
          pi = "#{si.left},#{si.top}"
          pj = "#{(sj.left + sj.width)},#{(sj.top + sj.height)}"
    
          #/* interpolate */
          if (i < k) 
            sk = scenes[i + 1]
            sl = scenes[j - 1]
            case (s.interpolate) 
              when "step-before"
                pi = pi+"V#{sk.top}"
                pj = pj+"H#{sl.left + sl.width}"
              
              when "step-after"
                pi = pi+"H#{sk.left}"
                pj = pj+"V#{sl.top + sl.height}"
            end
          end
    
          p1.push(pi);
          p2.push(pj);
          j=j-1
        }
        (p1+p2).join("L");
      }
        
      # @private Computes the curved path for the range [i, j]. */
      path_curve=lambda {|ii, j|
        pointsT = []
        pointsB = []
        pathT=nil
        pathB=nil
        
        
        k=j
        (ii..k).each {|i|
          sj = scenes[j];
          pointsT.push(scenes[i])
          pointsB.push(OpenStruct.new({:left=> sj.left + sj.width, :top=> sj.top + sj.height}))
          j=j-1
        }
    
        if (s.interpolate == "basis") 
          pathT = pv.SvgScene.curve_basis(pointsT);
          pathB = pv.SvgScene.curve_basis(pointsB);
        elsif (s.interpolate == "cardinal") 
            pathT = pv.SvgScene.curve_cardinal(pointsT, s.tension);
            pathB = pv.SvgScene.curve_cardinal(pointsB, s.tension);
        elsif # monotone
          pathT = pv.SvgScene.curve_monotone(pointsT);
          pathB = pv.SvgScene.curve_monotone(pointsB);
        end
    
        "#{pointsT[0].left },#{ pointsT[0].top }#{ pathT }L#{ pointsB[0].left},#{pointsB[0].top}#{pathB}"
          }
        
          #/* points */
          d = []
          si=nil
          sj=nil
          i=0
          while(i<scenes.size) 
            si = scenes[i]
            continue if (si.width==0 and si.height==0)
            j=0
            (i+1).upto(scenes.size-1) {|jj|
              j=jj; sj = scenes[jj];
              break if (si.width==0 and si.height==0)
            }
            
            i=i-1 if (i!=0 and (s.interpolate != "step-after"))
            j=j+1 if ((j < scenes.size) and (s.interpolate != "step-before"))
            d.push(((j - i > 2 and (s.interpolate == "basis" or s.interpolate == "cardinal" or s.interpolate == "monotone")) ? path_curve : path).call(i, j - 1))
            i = j - 1
            i+=1
          end
          
          return e if d.size==0
        
          e = self.expect(e, "path", {
              "shape-rendering"=> s.antialias ? nil : "crispEdges",
              "pointer-events"=> s.events,
              "cursor"=> s.cursor,
              "d"=> "M" + d.join("ZM") + "Z",
              "fill"=> fill.color,
              "fill-opacity"=> fill.opacity==0 ? nil : fill.opacity,
              "stroke"=> stroke.color,
              "stroke-opacity"=> stroke.opacity==0 ? nil : stroke.opacity,
              "stroke-width"=> stroke.opacity!=0 ? s.line_width / self.scale : nil
            });
          return self.append(e, scenes, 0);
    end
        
    def self.area_segment(scenes)
          
          e = scenes._g.elements[1]
          s = scenes[0]
          pathsT=[]
          pathsB=[]
          
          if (s.interpolate == "basis" or s.interpolate == "cardinal" or s.interpolate == "monotone") 
            pointsT = []
            pointsB = []
            n=scenes.size
            n.times {|i|
              sj = scenes[n - i - 1]
              pointsT.push(scenes[i])
              pointsB.push(OpenStruct.new({:left=> sj.left + sj.width, :top=> sj.top + sj.height}));
            }
        
            if (s.interpolate == "basis") 
              pathT = pv.SvgScene.curve_basis_segments(pointsT);
              pathB = pv.SvgScene.curve_basis_segments(pointsB);
            elsif (s.interpolate == "cardinal") 
                pathT = pv.SvgScene.curve_cardinal_segments(pointsT, s.tension);
                pathB = pv.SvgScene.curve_cardinal_segments(pointsB, s.tension);
            elsif # monotone
              pathT = pv.SvgScene.curve_monotone_segments(pointsT);
              pathB = pv.SvgScene.curve_monotone_segments(pointsB);
            end
          end
          n=scenes.size-1
          n.times {|i|
            
            s1 = scenes[i]
            s2 = scenes[i + 1]
        
            # /* visible */
            next if (!s1.visible or !s2.visible)
            
            fill = s.fill_style
            stroke = s.stroke_style            
            next e if (fill.opacity==0 and stroke.opacity==0) 
            d=nil
            if (pathsT) 
              pathT = pathsT[i]
              pb=pathsB[n - i - 1]
              pathB = "L" + pb[1,pb.size-1]
              d = pathT + pathB + "Z";
            else 
              #/* interpolate */
              si = s1
              sj = s2
              
              case (s1.interpolate) 
                when "step-before"
                  si = s2
                when "step-after"
                  sj = s1
              end
              
        
              #/* path */
              d = "M#{s1.left},#{si.top}L#{s2.left},#{sj.top }L#{s2.left + s2.width},#{sj.top + sj.height}L#{s1.left + s1.width},#{si.top + si.height}Z"
            end
        
            e = self.expect(e, "path", {
                "shape-rendering"=> s1.antialias ? null : "crispEdges",
                "pointer-events"=> s1.events,
                "cursor"=> s1.cursor,
                "d"=> d,
                "fill"=> fill.color,
                "fill-opacity"=> fill.opacity==0 ? nil : fill.opacity,
              "stroke"=> stroke.color,
              "stroke-opacity"=> stroke.opacity==0 ? nil : stroke.opacity,
              "stroke-width"=> stroke.opacity!=0 ? s1.line_width / self.scale : nil
              });
            e = self.append(e, scenes, i);
          }
          return e;
    end
  end
end