turtle mine gps

xSize = 9
ySize = 0
zSize = 9

startX, startY, startZ = 0, 0, 0
currentX, currentY, currentZ = 0, 0, 0
targetX, targetY, targetZ = 0, 0, 0

function refuel()
    if turtle.getItemCount(1) == 0 then
        print("Ran out of fuel :(")
        return false
    end

    if turtle.getFuelLevel() <= 0 then
        turtle.refuel(1)
        print("REFUELED")
        return true
    end

    return true
end

function move()
    currentX, currentY, currentZ = gps.locate(5)
    print("Current: " .. tostring(currentX) .. ", " .. tostring(currentY) .. ", " .. tostring(currentZ))

    if currentX == targetX then
        turtle.turnRight()
        turtle.dig()
        turtle.forward()
        turtle.turnRight()
    elseif currentX == startX then
        turtle.turnLeft()
        turtle.dig()
        turtle.forward()
        turtle.turnLeft()
    else
        turtle.dig()
        turtle.forward()
    end
end

startX, startY, startZ = gps.locate(5)
currentX, currentY, currentZ = startX, startY, startZ

targetX = startX + xSize
targetY = startY + ySize
targetZ = startZ + zSize

print("Start: " .. tostring(startX) .. ", " .. tostring(startY) .. ", " .. tostring(startZ))
print("End: " .. tostring(targetX) .. ", " .. tostring(targetY) .. ", " .. tostring(targetZ))

while true do
    if not refuel() then
        break
    end

    move()

    if currentX == targetX and currentY == targetY and currentZ == targetZ then
        break
    end
end