reprap = {}

-- adds <material> to each node in a line from <from_position> to <to_position>
function reprap.drawline3d(from_position, to_position, material)
   --modified 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
   --step through longest delta (which we have swapped to x)
   local cx, cy, cz
   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
	  print("drawing dot: "..cx..', '..cy..', '..cz)
      --minetest.env:add_node({ x = cx, y = cy, z = cz }, { name=material, param2=2 })
	  table.insert(line, { pos={ x = cx, y = cy, z = cz }, mat = material })
      --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

-- process a gcode file <filename> placing <material> on each point touched by the machine
function reprap.process_gcode(filename, material, center)
	local path = minetest.get_modpath("reprap").."/"..filename
	local nodes = {}
	local min = {x=center.x, y=center.y, z=center.z}
	local max = {x=center.x, y=center.y, z=center.z}
	local mat = minetest.get_content_id(material)

	local f = io.open(path)
	local line
	local cmd, param = "", ""
	local lastx, lasty, lastz
	local cmdx, cmdy, cmdz
	lastx = 0
	lasty = 0
	lastz = 0
	for line in f:lines() do
		if (line ~= "") and (line:sub(1,1) ~= ";") then
			if string.find(line, "G1 ") then
				cmdx = lastx
				cmdy = lasty
				cmdz = lastz
				for cmd, param in string.gmatch(line, "(%w)([0-9.-]+)") do
					param = tonumber(param)
					if cmd == "X" then
						cmdx = param
					elseif cmd == "Y" then
						cmdz = param
					elseif cmd == "Z" then
						cmdy = param
					end
				end
				local p1 = { x = center.x + lastx, y = center.y + lasty, z = center.z + lastz }
				local p2 = { x = center.x + cmdx, y = center.y + cmdy, z = center.z + cmdz }
				min, max = check_pos(min, max, p1)
				min, max = check_pos(min, max, p2)

				table.insert(nodes, 
				reprap.drawline3d(
					p1, 
					p2, 
					mat
						 )
					    )
				lastx = cmdx
				lasty = cmdy
				lastz = cmdz
			end
		end
	end

	local vm = VoxelManip()
	--print("min: .."..dump(min).." max: "..dump(max))
	min, max = vm:read_from_map(min, max)
	--print("min: .."..dump(min).." max: "..dump(max))
	local area = VoxelArea:new{ MinEdge = min, MaxEdge = max }
	local data = vm:get_data()
	
	for _, lines in pairs(nodes) do
	for _, node in pairs(lines) do
	   local index = area:indexp(node.pos)
	   data[index] = node.mat
	end
	end
	
	vm:set_data(data)
	vm:write_to_map()
	vm:update_map()
end

minetest.register_chatcommand("reprap", {
		params = "<gcodefilename>,<material>,<x>,<y>,<z>",
		description = "start printing a gcode file",
		privs = {},
		func = function(name, param)
			local paramlist
			print(param)
			paramlist = string.split(param, ",")
			print(paramlist[1])
			print(paramlist[2])
			print(paramlist[3])
			print(paramlist[4])
			print(paramlist[5])
			filename = paramlist[1]
			material = paramlist[2]
			drawx = tonumber(paramlist[3])
			drawy = tonumber(paramlist[4])
			drawz = tonumber(paramlist[5])
			reprap.process_gcode(filename, material, { x=drawx, y=drawy, z=drawz })
			-- reprap.process_gcode("column.gcode", "default:mese", { x=-65, y=0, z=77 })
		end
	}
)

function check_pos(min, max, pos)
   if pos.x < min.x then min.x = pos.x end
   if pos.y < min.y then min.y = pos.y end
   if pos.z < min.z then min.z = pos.z end
   if pos.x > max.x then max.x = pos.x end
   if pos.y > max.y then max.y = pos.y end
   if pos.z > max.z then max.z = pos.z end
   return min, max
end