PortalTurtle

-- Portal Turtle v 2.2 (inspired by Armitige Shanks You Tube video of same)
-- by Mike Simpkins December 2013 (Creative Commons)
-- Paired with Portal Computer (http://pastebin.com/amCuLiLa)

local page = 1
local id = os.getComputerID()
-- set the id values to reflect this and other turtles
if (id==132) then page=1 elseif (id==129) then page = 2 else page = 3 end
local slots={}
control=0
local message=""

--Announce Turtle to Controller
function announceTurtle()
    -- Turn on Modem
    if(not rednet.isOpen("right")) then rednet.open("right") end
    displayStatus("Announcing Turtle...")
    repeat
        timer=os.startTimer(3)
        rednet.broadcast("TURTLE"..page)

        repeat
            event,control,message,_ = os.pullEvent()
            --print(message or "null")
        until ((event=="rednet_message" and message=="CONTROL") or (event=="timer" and control==timer))
    until (message =="CONTROL")
    initTurtle()
end

--Initialize turtle inventory and communicate with controller
function initTurtle()
    displayStatus(" Initializing...",10,0)
    --print ("Begin Init Turtle")
    local zeroCount = 0
    local slot
    local status


    --Reset Router
    redstone.setOutput("bottom", false)
    sleep (.2)
    redstone.setOutput("bottom", true)

    -- Check Inventory
    for slot=1,16 do
        slots[slot]=turtle.getItemCount(slot)
        if (slots[slot]==0) then zeroCount=zeroCount+1 end
    end

    -- Turn on Modem
    if(not rednet.isOpen("right")) then rednet.open("right") end
    --print("modem is on")
    if  (zeroCount>0) then
        status = textutils.serialize(slots)
        else
        status = "FULL"
    end
    repeat
        --print("Sending message to "..control)
        rednet.send(control,"InitTurtle"..page,true)
        --print ("Message Sent")
        repeat
            timer=os.startTimer(3)
            event,sender, message,_ = os.pullEvent("rednet_message")
            --print ("Sender = "..sender.." message= "..message)
        until ((event=="rednet_message" and sender==control) or (event=="timer" and sender==timer))
    until (message==("PROCEED"..page))
    --print ("Given PROCEED")
    repeat
        rednet.send(control,status,true)
        repeat
            sender, message,_ = rednet.receive()
        until (sender==control)
    until (message==status)
    rednet.send(control,"OK"..page,true)
    --print("Turtle"..page.." initialized")
    displayStatus("Connected",12,0)
end

function displayStatus(state, line, clearScreen)
    line = line or 7
    clearScreen = clearScreen or 1
    if (clearScreen==1) then term.clear() end
    local position = math.ceil((39-#state)/2)
    term.setCursorPos(position,line)
    term.write(state)
end
function placeBook(book)

    if (book>0 and book<17 and turtle.getItemCount(book)>0) then
        displayStatus("Placing Book"..tostring(book),7)
        turtle.select(book)
        turtle.drop(1)
        return "OK"
    else
        displayStatus("No Book in Slot",11,0)
        return "NoBook"
    end
end

function pullBook(book)
    displayStatus("Pulling Book"..tostring(book),9,0)
    -- force router to eject
    redstone.setOutput("bottom", false)
    sleep (.2)
    -- check book placement, if placed in wrong slot move it
    if turtle.getItemCount(book)==0 then
        for slot=1,16 do
            if (turtle.getItemCount(slot)~=slots[slot]) then
                --print ("Bad Slot")
                turtle.select(slot)
                xferResult =true

                if (not turtle.transferTo(book,1)) then
                    --print("could not moved book to "..tostring(slot))
                    slots[slot]=turtle.getItemCount(slot)
                else
                    --print("moved book to "..tostring(slot))
                    break
                end
            end
        end
    end
    redstone.setOutput("bottom", true) -- turns router back on
end


announceTurtle()
while true do
    displayStatus("Awaiting Command")
    event,arg1,arg2,arg3,arg4,a4g5 =os.pullEvent()
    --print("Event ="..tostring(event).." Message "..tostring(arg2))
    if event=="rednet_message" and arg1~=os.getComputerID() then
        sender = arg1
        message = arg2
        if (sender==control or message=="ANNOUNCE") then --only messages from send or ANNOUNCE Broadcasts
            --print("Control Message = "..message)
            if (message=="ANNOUNCE") then
                control = sender
                announceTurtle()
            elseif (message=="InitTurtle"..page) then --Request from Controller to init this turtle
                initTurtle()
            elseif (string.sub(message,1,7)=="GetBook") then
                book = tonumber(string.sub(message,8))
                result = placeBook(book)
                rednet.send(control,result,true)
                if (result=="OK") then
                    sleep(4)
                    rednet.send(control,"READY",true)
                    sleep(2)
                    pullBook(book)
                end
            else
                rednet.send(control,"FAIL " ..message,true)
            end
        end
    elseif (event=="char" and arg1=="a") then announceTurtle()
    end
end