position

--os.loadAPI("theinsekt/turtle2")

-- TODO: Change so that multiple positions can be used.
-- this can implemented by not using these local variables and
-- instead working on a position table.
-- Then a new table can be created and changed independently
-- of the old one.
x=0 -- forward, back
y=0 -- up, down
z=0 -- right, left (not turn)
rot=0 -- direction/rotation the turtle is facing

-- this can be used to make sure
-- the turtle isn't outside a
-- cube of a certain size
function getLargest()
  -- make local copies of the coordinates
  -- but use the absolute value
  local x=math.abs(x)
  local y=math.abs(y)
  local z=math.abs(z)
  if x>y then
    if x>z then
      return x
    else
      return z
    end
  else
    if y>z then
      return y
    else
      return z
    end
  end
end

function printit()
  print("before: "..x.." "..y.." "..z.." "..rot)
end

function reset()
  x=0
  y=0
  z=0
  rot=0
end

-- put function in the table
horzT={
  [0]=function(length)
    x=x+length
  end,
  [1]=function(length)
    z=z+length
  end,
  [2]=function(length)
    x=x-length
  end,
  [3]=function(length)
    z=z-length
  end,
}

-- table that can update the coordinates
-- if you go a given length in the
-- in a direction
updateT={
  f=function(length)
    horzT[rot](length)
  end,
  b=function(length)
    horzT[rot](length)
  end,
  u=function(length)
    y=y+length
  end,
  d=function(length)
    y=y-length
  end,
  r=function(length)
   rot=(rot+length)%4
  end,
  l=function(length)
    rot=(rot-length)%4
  end,
}

-- updates the position values
-- given the input values
-- returns nil
function update(dir, length)
  --print("before: "..x.." "..y.." "..z.." "..rot)
  --print(dir.." "..length)
  updateT[dir](length)
  --print("after: "..x.." "..y.." "..z.." "..rot)
end

function whatIf(dir, length)
  update(dir,length)
  local a, b, c, d=get()
  update(dir,-length)
  return a,b,c,d
end

function whatIfLargest(dir, length)
  update(dir,length)
  local res=getLargest()
  --print(x.." "..y.." "..z" "..rot)
  update(dir,-length)
  return res
end

-- returns the position values
-- x,y,z,rot
function get()
  return x, y, z, rot
end