trainBridgeV3

turtle.select(1)

ender_chest_slot = 16

function check_inventory()
    local all_empty = false
    local data

    while true do
        data = turtle.getItemDetail(turtle.getSelectedSlot())

        if data == nil then
            turtle.select(turtle.getSelectedSlot()+1)
        elseif data.name ~= "minecraft:oak_planks" then
            turtle.select(turtle.getSelectedSlot()+1)
        else
            print("Track found in slot ", turtle.getSelectedSlot())
            break
        end

        if turtle.getSelectedSlot() >= ender_chest_slot then
            print("Last searchable slot reached")
            turtle.select(1)
            if all_empty then
                break
            end
            all_empty = true
        end
    end

    return all_empty
end

function get_more_rails()
    local all_empty = false
    local data
    turtle.select(ender_chest_slot)
    turtle.place()
    turtle.select(1)

    while true do
        data = turtle.getItemDetail(turtle.getSelectedSlot())
        if data == nil then
            if turtle.suck(64) == false then
                break
            end
        elseif data.name ~= "minecraft:oak_planks" then
            turtle.dropDown()
            if turtle.suck(64) == false then
                break
            end
        end

        turtle.select(turtle.getSelectedSlot()+1)

        if turtle.getSelectedSlot() >= ender_chest_slot then
            turtle.select(1)
            if all_empty then
                break
            end
            all_empty = true
        end
    end

    turtle.select(ender_chest_slot)
    turtle.dig()
    turtle.select(1)
end

function dig_down()
    local success, data
    success, data = turtle.inspectDown()
    if success then
        if (data.name == "minecraft:kelp") or (data.name == "environmental:cattail") then
            turtle.digDown()
        end
    end
end

bigSleep = false

while true do
    while turtle.detectUp() do
        sleep(0.5)
        bigSleep = true
    end

    if bigSleep then
        sleep(5.0)
        bigSleep = false
    end

    if check_inventory() then
        get_more_rails()
    end

    dig_down()
    turtle.placeDown()
    turtle.forward()
end