driveworker

function get_empty_slot()
    found_empty = false
    for i=1, 16 do
        if turtle.getItemCount() == 0 then
            found_empty = true
            break
        end
    end
    return found_empty
end

function starts_with(str, start)
   return str:sub(1, #start) == start
end

function ends_with(str, ending)
   return ending == "" or str:sub(-#ending) == ending
end

function update_index()
    foreign_items = 0
    for i=1, 16 do
        turtle.select(i)
        item = turtle.getItemDetail()
        if item then
            if item.name == top_item then
                turtle.dropUp()
            else
                if item.name == bottom_item then
                    turtle.dropUp()
                else
                    foreign_items = foreign_items + item.count
                end
            end
        end
    end

    if foreign_items > 0 then
        print("WARNING: " .. tostring(foreign_items) .. " FOREIGN ITEMS DETECTED")
    end

    if not get_empty_slot() then
        print("WARNING: FULL INVENTORY")
    else
        top_item = nil
        bottom_item = nil
        if turtle.suckUp(1) then
            top_item = turtle.getItemDetail().name
            turtle.dropUp(1)
        end
        if turtle.suckDown(1) then
            bottom_item = turtle.getItemDetail().name
            turtle.dropDown(1)
        end
    end

    print("Top container: " .. tostring(top_item))
    print("Bottom container: " .. tostring(bottom_item))
end

rednet.open("left")

top_item = nil
bottom_item = nil

last = nil
first = nil

last = not turtle.detect()

a, b = turtle.inspectDown()
first = b.name == "minecraft:obsidian"

if not first then
    update_index()
end

neighbor = nil
if not last then
    neighbor = peripheral.wrap("front")
end

if first then
    while true do
        term.write(">>> ")
        command = read()
        if command == "index" then
            rednet.send(neighbor.getID(), {}, "index")
            sender, message, protocol = rednet.receive()
            print("There are " .. tostring(table.getn(message)) .. " nodes connected to the network")
        end
        if command == "reboot" then
            rednet.send(neighbor.getID(), ".", "reboot")
            os.reboot()
        end
        if command == "print" then
            term.write("Enter message: ")
            rednet.send(neighbor.getID(), read(), "print")
        end
        if command == "get" then
            term.write("Enter item name: ")
            item = read()
            term.write("How many: ")
            count = read()
            if count == "" then
                count = "64"
            end
            rednet.send(neighbor.getID(), {item, count}, "get")
            sender, message, protocol = rednet.receive()
            if message == true then
                turtle.suck()
                print("Sucessfully retrieved item")
            else
                print("Failed to find item")
            end
        end
        if command == "store" then
            turtle.select(1)
            item = turtle.getItemDetail()
            if item then
            else
                print("Nothing to store")
            end
        end
    end
else
    while true do
        sender, message, protocol = rednet.receive()
        print(protocol .. ": " .. tostring(message))
        if protocol == "index" then
            modified_message = message
            table.insert(modified_message, os.getComputerID())
            if last then
                rednet.send(sender, modified_message, "index")
            else
                rednet.send(neighbor.getID(), modified_message, "index")
                neighbor_reply_id, index_reply, index_protocol = rednet.receive(1)
                if neighbor_reply_id then
                    rednet.send(sender, index_reply, "index")
                else
                    print("No response from neighbor")
                    rednet.send(sender, "Unresponsive neighbor", "error")
                end
            end
        end
        if protocol == "get" then
            found = false
            if not (top_item == nil) and ends_with(top_item, message[1]) then
                turtle.suckUp(tonumber(message[2]))
                found = true
            end
            if not (bottom_item == nil) and ends_with(bottom_item, message[1]) then
                turtle.suckDown(tonumber(message[2]))
                found = true
            end
            if found then
                rednet.send(sender, true, "get")
                while turtle.getItemCount() > 0 do
                    sleep(0.1)
                end
                update_index()
            else
                if last then
                    rednet.send(sender, false, "get")
                else
                    rednet.send(neighbor.getID(), message, "get")
                    neighbor_reply_id, get_reply, get_protocol = rednet.receive(1)
                    if neighbor_reply_id then
                        if get_reply == true then
                            turtle.suck(64)
                        end
                        rednet.send(sender, get_reply, "get")
                    else
                        print("No response from neighbor")
                        rednet.send(sender, "Unresponsive neighbor", "error")
                    end
                end
            end
        end
        if protocol == "reboot" then
            if not last then
                rednet.send(neighbor.getID(), ".", "reboot")
            end
            os.reboot()
        end
        if protocol == "print" then
            if not last then
                rednet.send(neighbor.getID(), message, "print")
            end
            print("MESSAGE: " .. message)
        end
    end
end