Bridge

local bridgeLength = 0
local slotCount = 16
local blockSlot = 1

print("How long would you like your stairs?")
bridgeLength = tonumber(read())

if(bridgeLength <= 0) then
    print("Malformed Size Given")
    return
end

function CheckFuel()
    if(turtle.getFuelLevel() < 10) then
        for slot = 1, slotCount do
            print("Attempting to refuel on slot " .. slot)
            turtle.select(slot)
            if(turtle.refuel(1)) then
                turtle.select(blockSlot)
                return true
             end
        end
        return false
    end
    return true
end

function CheckBlock()
    if(turtle.getItemCount() > 0) then
        if(turtle.placeDown()) then
            return true
        end
    end

    for slot = 1, slotCount do
        turtle.select(slot)
        if(turtle.placeDown()) then
            blockSlot = slot
            return true
        end
    end
end

function PlaceBlock()
    if(turtle.placeDown()) then
        return true
    elseif(CheckBlock()) then
        return true
    end
end

function moveForwards()
    turtle.forward()
end


--Main-----------------------

for stair = 1, bridgeLength do
    if(CheckFuel()) then
       if (PlaceBlock()) then
            moveForwards()
       else
        print("Out of blocks to use/Land Reached")
        return
       end
    else
        print("No Fuel Detected")
        return
    end
end