roads = {}
roads.pos1 = {}
roads.pos2 = {}
roads.ok = false
roads.path = {}

minetest.register_tool("roads:tool", {
    description = "roads edit tool",
    inventory_image = "default_stick.png",
    on_use = function(itemstack, user, pointed_thing)
       local pos = pointed_thing.above
       local name = user:get_player_name()
       if roads.ok then
          minetest.chat_send_player(name,"made road")

          roads.path = minetest.find_path(roads.pos1,roads.pos2,
                 5,
                 1,
                 1,
                 "A*")

         --roads.path = line3d(roads.pos1, roads.pos2)
          print(dump(roads.path))
          local l = path2line(roads.path)
          print(dump(l))
          for k, v in pairs(l) do
         minetest.set_node(v, { name = "wool:red" } )
          end
          roads.pos1 = {}
          roads.pos2 = {}
          roads.path = {}
          roads.ok = false
       elseif roads.pos1.x then
          roads.pos2 = pos
          minetest.chat_send_player(name,"pos2 set")
          roads.ok = true
       else
          roads.pos1 = pos
          minetest.chat_send_player(name,"pos1 set")
       end
    end,
})

path2line = function(path)
   local line = {}
   local pos1, pos2
   pos1 = path[1]
   for k, v in pairs(path) do
      pos2 = v
      local l = line3d(pos1, pos2)
      for k, v in pairs(l) do
     table.insert(line, v)
      end
      pos1 = v
   end
   return line
end

--line2street = function(line)
   --for k, v in pairs(line) do
      --turn turtle forward (starts facing up)
      --find angle perpendicular to direction
      --set angle, spawn axiom, something like "TTTTFTTTT"
      --with appropriate materials in treedef
      --spawn "tree"
   --end
--end

line3d = function(from_position, to_position)
--from https://github.com/ryanramage/bresenham3d/blob/master/index.js
--lua port by jin_xi
   local line = {}
   local temp

   local x0 = math.floor(from_position.x)
   local y0 = math.floor(from_position.y)
   local z0 = math.floor(from_position.z)
   local x1 = math.floor(to_position.x)
   local y1 = math.floor(to_position.y)
   local z1 = math.floor(to_position.z)

   --'steep' xy Line, make longest delta x plane
   local swap_xy = math.abs(y1 - y0) > math.abs(x1 - x0)
   if swap_xy then
      temp = x0; x0 = y0; y0 = temp --swap(x0, y0);
      temp = x1; x1 = y1; y1 = temp --swap(x1, y1);
   end

   local swap_xz = math.abs(z1 - z0) > math.abs(x1 - x0)
   if swap_xz then
      temp = x0; x0 = z0; z0 = temp --swap(x0, z0);
      temp = x1; x1 = z1; z1 = temp --swap(x1, z1);
   end

   --delta is Length in each plane
   local delta_x = math.abs(x1 - x0)
   local delta_y = math.abs(y1 - y0)
   local delta_z = math.abs(z1 - z0)

   --drift controls when to step in 'shallow' planes
   --starting value keeps Line centred
   local drift_xy = (delta_x / 2)
   local drift_xz = (delta_x / 2)

   --direction of line
   local step_x = 1
   if x0 > x1 then step_x = -1 end
   local step_y = 1
   if y0 > y1 then step_y = -1 end
   local step_z = 1
   if z0 > z1 then step_z = -1 end

   --starting point
   local y = y0
   local z = z0

   local cx, cy, cz

   --step through longest delta (which we have swapped to x)
   for x = x0, x1, step_x do

      --copy position
      cx = x; cy = y; cz = z

      --unswap (in reverse)
      if swap_xz then
     temp = cx; cx = cz; cz = temp --swap(cx, cz)
      end
      if swap_xy then
     temp = cx; cx = cy; cy = temp --swap(cx, cy)
      end

      table.insert(line, { x = cx, y = cy, z = cz } )

      --update progress in other planes
      drift_xy = drift_xy - delta_y
      drift_xz = drift_xz - delta_z

      --step in y plane
      if drift_xy < 0 then
     y = y + step_y
     drift_xy = drift_xy + delta_x
      end

      --same in z
      if (drift_xz < 0) then
     z = z + step_z
     drift_xz = drift_xz + delta_x
      end
   end
   return line
end