killer

local pos = {
  x = 0,
  y = 0,
  z = 0,
  facing = 0
}

local function setX(x)
  pos.x = x
end
local function getX()
  return pos.x
end
local function setY(y)
  pos.y = y
end
local function getY()
  return pos.y
end
local function setZ(z)
  pox.z = z
end
local function getZ()
  return pos.z
end
local function setFacing(f)
  pos.facing = f
end
local function getFacing()
  return pos.facing
end

local function turnleft()
  pos.facing = pos.facing - 1
  if pos.facing == -1 then pos.facing = 3 end
  turtle.turnLeft()
end

local function moveforward(distance)
   if turtle.forward() then
      if pos.facing == 0 then
        pos.z = pos.z + 1
      elseif pos.facing == 2 then
        pos.z = pos.z - 1
      elseif pos.facing == 1 then
        pos.x = pos.x - 1
      elseif pos.facing == 3 then
        pos.x = pos.x + 1
      end
      return true
    else
      return false
    end
end

local function turnright()
  pos.facing = pos.facing + 1
  if pos.facing == 4 then pos.facing = 0 end
  turtle.turnRight()
end

local function turnaround()
  turnright()
  turnright()
end

local function face (faceto)
  local dirdif = faceto-pos.facing
  if dirdif == 1 then turnright()
  elseif dirdif == -3 then turnright()
  elseif dirdif == -1 then turnleft()
  elseif dirdif == 3 then turnleft()
  elseif dirdif == 2 then
    turnaround()
  elseif dirdif == -2 then
    turnaround()
  end
end

local function movez(distance)
  if distance ~= 0 then
    if distance < 0 then
      face(2)
    elseif distance > 0 then
      face(0)
    end
    return moveforward(math.abs(distance))
  end
end


local function moveup(distance)
    if turtle.up() then
      pos.y = pos.y+1
      return true
    end
    return false
end

local function movedown(distance)
    if turtle.down() then
      pos.y = pos.y-1
      return true
    end
    return false
end

local function movex(distance)
  if distance ~= 0 then
    if distance < 0 then
      face(1)
    elseif distance > 0 then
      face(3)
    end
    return moveforward(math.abs(distance))
  end
end

local function movey(distance)
  if distance ~= 0 then
    if distance < 0 then
      return movedown(math.abs(distance))
    elseif distance > 0 then
      return moveup(distance)
    end
  end
end

local function headTo(x, y, z)
  if math.abs(x) > math.abs(y) then
    if math.abs(x) > math.abs(z) then
      if x > 0 then movex(1) else movex(-1) end
    else
      if math.abs(z) > math.abs(y) then
        if z > 0 then movez(1) else movez(-1) end
      else
        if y > 0 then movey(1) else movey(-1) end
      end
    end
  else
    if math.abs(y) > math.abs(z) then
        if y > 0 then movey(1) else movey(-1) end
    else
      if math.abs(x) > math.abs(z) then
        if x > 0 then movex(1) else movex(-1) end
      else
        if z > 0 then movez(1) else movez(-1) end
      end
    end
  end
end

local function getdistance(entity)
  return  math.abs(entity.Position.X) + math.abs(entity.Position.Y) + math.abs(entity.Position.Z)
end

local sensor = peripheral.wrap("right")
while true do
  local targets = sensor.getTargets()
  local closest
  local closestDistance = 10000000
  for k, btarget in pairs(targets) do
    if getdistance(btarget) < closestDistance and btarget.type ~= "Player" then
      closestDistance = getdistance(btarget)
      closest = btarget
    end
  end
  if closest ~= nil then
      headTo(closest.Position.X, closest.Position.Y, closest.Position.Z)
  else
   sleep(0.1)
  end
   print(closestDistance)
  if closestDistance < 4 then
   turtle.attack()
  end
end