require 'sketchup.rb'

def divide_cpoint
model=Sketchup.active_model
@e=Sketchup.active_model.selection[0]
ents=model.active_entities
@subdiv=2
@arc_type="Arc"
pts=[]
ind_pts={}
model.start_operation "Divide with construction points"
if Sketchup.active_model.selection.length == 1
  @obj_type="Edge"
  @e=model.selection[0]
  elsif @e.curve.typename == "ArcCurve"
    verts=@e.curve.vertices
    if verts[0].position == verts[verts.length-1].position
      @arc_type="Circle"
      @obj_type="Arc"
      else
      @obj_type="Arc"
    end
    @e=model.selection[0].curve
  else
  UI.messagebox("Unsupported curve. Aborting...")
  return nil
end

case @obj_type
when "Edge"
  @ps=@e.start.position
  @pe=@e.end.position
  @v=@ps.vector_to @pe
  @vlength=@v.length
  r=divide_cpoint_dialog
  @subdiv=r[1]
  @explode=r[0]
  # Generate points along @v
  pts.push(@ps)
  1.upto(@subdiv-1) do |i|
    @v.length=i*(@vlength/@subdiv)
    cp=ents.add_cpoint(@ps.offset(@v))
    pts.push(cp.position)
  end
  pts.push(@pe)
  if @explode == "Yes"
    @e.erase!
    0.upto(@subdiv-1) do |line|
      ents.add_line pts[line], pts[line+1]
    end
  end
when "Arc"
  @ps=@e.first_edge.start.position
  @pe=@e.last_edge.end.position
  @verts=@e.vertices
  @verts.freeze
  @nsegs=@e.count_edges
  @clength=@e.length
  @unit_seg=@clength/@nsegs
  r=divide_cpoint_dialog
  @subdiv=r[1]
  @explode=r[0]
  @unit_length=@clength/@subdiv
  
  1.upto(@subdiv-1) do |i|
    current_length=i*@unit_length
    n_seg=(current_length/@unit_seg).to_i
    current_seg=@e.edges[n_seg]
    @p1=current_seg.start.position
    @p2=current_seg.end.position
    @v=@p1.vector_to @p2
    @remaining=current_length-(n_seg*@unit_seg)
    @v.length=@remaining
    @p=@p1.offset(@v)
    cp=ents.add_cpoint(@p)
    pts.push(cp.position)
    ind_pts[cp]=n_seg
  end
  
  if @arc_type == "Circle"
    cp=ents.add_cpoint(@pe)
    pts.push(cp.position)
  end
  
  #Explode option
  if @explode == "Yes"
    org_verts=[]
    @verts.each do |p|
      org_verts.push(p.position)
    end
    Sketchup.active_model.selection.each { |o| o.erase! }
    # Sort vertives and new cpoints
    all_pts=sort_cpoints(org_verts,pts)
    ents.add_line all_pts
  end
end #case

model.commit_operation
end

def sort_cpoints(verts,cpoints)
  new_pts=[]
  0.upto(verts.length-2) do |i|
    p1=verts[i]
    p2=verts[i+1]
    new_pts.push(p1)
    cpoints.each do |cp|
      if cp.on_line? [p1, (p1.vector_to p2)]
        new_pts.push(cp)
      end
    end
    new_pts.push(p2)
  end
  return new_pts
end

def divide_cpoint_dialog
  s=2 if not s
  list=["Yes","No"].join("|")
  prompts=["Explode at points: ","Segments:"]
  values=["No",s]
  enums=[list]
  results = inputbox prompts, values, enums, "Divide"
  return if not results
  return results
end

def divide_cpoint_valid_selection
  return true if Sketchup.active_model.selection[0].typename == "Edge"
end

if not $divide_cpoint_loaded
  UI.add_context_menu_handler do |menu|
    if divide_cpoint_valid_selection
      menu.add_item("Divide with construction points") { divide_cpoint }
    end
  end
end
$divide_cpoint_loaded=true