Computercraft Delivery Turtle

modem = peripheral.wrap("left")
modem.open(500)
term.clear()
term.setCursorPos(1,1)
term.write("My X: ")
x = tonumber(io.read())
term.setCursorPos(1,2)
term.write("My Y: ")
y = tonumber(io.read())
term.setCursorPos(1,3)
term.write("My Z: ")
z = tonumber(io.read())
term.setCursorPos(1,4)
term.write("Facing (xp/xn/zp/zn): ")
facing = io.read()
term.setCursorPos(1,5)
term.write("Waiting for instructions...")
term.setCursorPos(1,6)
event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
px = tonumber(message)
event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
py = tonumber(message)
event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
pz = tonumber(message)
notthere = true
direction = "x"
while notthere do
    if px > x and direction == "x" then
        if facing == "xn" then
            turtle.turnLeft()
            turtle.turnLeft()
        end
        if facing == "zp" then
            turtle.turnLeft()
        end
        if facing == "zn" then
            turtle.turnRight()
        end
        facing = "xp"
        turtle.dig()
        if turtle.forward() then
            x = x + 1
        end
    end
    if px < x and direction == "x" then
        if facing == "xp" then
            turtle.turnLeft()
            turtle.turnLeft()
        end
        if facing == "zp" then
            turtle.turnRight()
        end
        if facing == "zn" then
            turtle.turnLeft()
        end
        facing = "xn"
        turtle.dig()
        if turtle.forward() then
            x = x - 1
        end
    end
    if px == x and direction == "x" then
       direction = "z"
    end
    if pz > z and direction == "z" then
        if facing == "xn" then
            turtle.turnLeft()
        end
        if facing == "zn" then
            turtle.turnLeft()
            turtle.turnLeft()
        end
        if facing == "xp" then
            turtle.turnRight()
        end
        facing = "zp"
        turtle.dig()
        if turtle.forward() then
            z = z + 1
        end
    end
    if pz < z and direction == "z" then
        if facing == "xp" then
            turtle.turnLeft()
        end
        if facing == "zp" then
            turtle.turnLeft()
            turtle.turnLeft()
        end
        if facing == "xn" then
            turtle.turnRight()
        end
        turtle.dig()
        if turtle.forward() then
            z = z - 1
        end
    end
    if pz == z and direction == "z" then
        direction = "y"
    end
    if py > y and direction == "y" then
        turtle.digUp()
        if turtle.up() then
            y = y + 1
        end
    end
    if py < y and direction == "y" then
        turtle.digDown()
        if turtle.down() then
            y = y - 1
        end
    end
    if py == y and direction == "y" then
        notthere = false
    end
end
modem.transmit(500, 500, "Arrived")