Turtle Bomber

args = {...}
d = 0
distance = args[1]
tonumber(distance)
tx = args[1]
ty = args[2]
tz = args[3]
hx,hy,hz = gps.locate()
x = hx
y = hy
z = hz
print("home:",hx,hy,hz)
print("target:",tx,ty,tz)
planted = false
function Refuel()
    d2 = (2*math.abs(tx-hx)+2*math.abs(tz-hz)+math.abs(120-hy)+math.abs(120-ty))
    n=math.ceil(d2/80)
    print(n)
    turtle.select(1)
    turtle.refuel(n)
end

function Det()
 print(table.getn(args))
 i = table.getn(args)
 if i == 0 or i == nil then
 printError("Nothing Defined, Use distance or coordinates")
 elseif i == 1 then
 print("Running In Distance Mode")
 Run()
 elseif i == 3 then
 print("Running In GPS Mode")
 GPSCal()
 elseif i >= 3 then
 printError("Too many Arguments")
 end
end

function GPSCal()
    Refuel()
    --go up to lvl 120
    while y < 120 do
    turtle.up()
    y = y+1
    end
    --calibrate x and y
    ix,iy,iz = gps.locate()
    turtle.forward()
    x,y,z = gps.locate()
    if x - ix == 1 then
    RunGPS()
    elseif x - ix == -1 then
    turtle.turnRight()
    turtle.turnRight()
    RunGPS()
    elseif z - iz == 1 then
    turtle.turnLeft()
    RunGPS()
    elseif z - iz == -1 then
    turtle.turnRight()
    RunGPS()
    else
    printError("GPS ERROR")
    end
end

function RunGPS()
    x,y,z = gps.locate()
    --go x
    if x < tonumber(tx) then
    while x<tonumber(tx) do
    if turtle.getFuelLevel() == 0 then
    Refuel()
    end
    turtle.forward()
    x=x+1
    end
    elseif x > tonumber(tx) then
    while x>tonumber(tx) do
    if turtle.getFuelLevel() == 0 then
    Refuel()
    end
    turtle.back()
    x=x-1
    end
    end
    --go z
    if z<tonumber(tz) then
    turtle.turnRight()
    while z<tonumber(tz) do
    if turtle.getFuelLevel() == 0 then
    Refuel()
    end
    turtle.forward()
    z=z+1
    end
    elseif z>tonumber(tz) then
    turtle.turnLeft()
    while z>tonumber(tz) do
    if turtle.getFuelLevel() == 0 then
    Refuel()
    end
    turtle.forward()
    z=z-1
    end
    end
    --DESCEND
    while y>tonumber(ty) or turtle.detectDown() == false do
    if turtle.getFuelLevel() == 0 then
    Refuel()
    end
    turtle.down()
    y=y-1
    if turtle.detectDown() == true then
    if planted == false then
    Plant()
    else
    print("home")
    end
    end
    end
end

function Run()
turtle.refuel(math.ceil(tx/80))
redstone.setOutput("right", false)
while tonumber(d) < tonumber(distance) do
if turtle.detect() == false then
turtle.forward()
d = d+1
elseif turtle.detect() == true then
Plant()
elseif d == distance then
Plant()
end
end
end

function Plant()
turtle.back()
turtle.select(2)
turtle.place()
turtle.back()
turtle.back()
turtle.select(3)
turtle.place()
turtle.turnLeft()
redstone.setOutput("right", true)
planted = true
tx = hx
ty = hy
tz = hz
GPSCal()
end
Det()