XP Turtle v0.1

--TODO :     make check for slot 1 being empty
--            create exit for when chest is full


--Load the saved Turtle state from disk if available, if not set to 0
function loadState()
    if fs.exists("xpTurtleState") then
        local file = fs.open("xpTurtleState","r")
        data = file.readAll()
        file.close()
        data=tonumber(data)
        moveState=data
    else
        print("debug -- no xpTurtleState found, setting movement state to 0\n")
        moveState = 0
    end
end

-- Save the current state to disk
function saveState(a)
    local file = fs.open("xpTurtleState","w")
    file.write(a)
    file.close()
--    io.write(string.format("debug -- wrote %s to file\n",a))

end

-- Check where the turtle is right now, and it it isn't at block 0, move there
function moveToStart()
    loadState()
--    io.write(string.format("debug -- Moving %s blocks to starting point\n", moveState))
    if moveState~=nil then
        printStatus("moving to start", getLvl())
        moveForward(moveState)
    end
end

-- Move forward with checking for blockage and save the move state
function moveForward(nDistance)
    printStatus("moving to start", getLvl())
--    print("moveForward nDistance is  ", nDistance)
    while nDistance > 0 do
        if turtle.forward() then
            nDistance=nDistance-1
            moveState = moveState -1
            saveState(moveState)
        else
            sleep(0.5)
        end
    end
end

-- Move back with checking for blockage and save the move state
function moveBack(nDistance)
    while nDistance > 0 do
        printStatus("moving to enchant area", curLev)
--        print("moveBack () nDistance is  ", nDistance)
        if turtle.back() then
            nDistance=nDistance-1
            moveState = moveState +1
            saveState(moveState)
        else
            sleep(0.5)
        end
    end
end


-- check if there's enough fuel, if not refuel from slot 16. If no fuel available, exit.
function checkFuel()
    if turtle.getFuelLevel()<20 then
        if    turtle.getItemCount(16)>=1 then
            turtle.select(16)
            turtle.refuel(1)
        else
            exitMsg(1)            
        end
    end

end

-- get the current level of the turtle
function getLvl()
    curLev = m.getLevels()
    return curLev
end

-- Check if nLvl(default=30) levels have been reached, if not wait, if yes, return true.
function checkLevel(nLvl)
    getLvl()
    if curLev<nLvl then
        printStatus("gathering XP", curLev)
        return false
    else
        printStatus("moving to enchant area", getLvl())
        return true
    end
    
end

-- Look for items to enchant in slots 2 through 14, if there are none, default to findBooks()
function getItems()
    for i=2,14 do
        if turtle.getItemCount(i)>0 then
            turtle.select(i)
            turtle.transferTo(1,1)
            turtle.select(1)
            return true
        end
    end
--        print("no items found, trying to find books")
    if findBook() then
    --        print("Books found")
        return true
    else
        return false
    end

end

-- Get books from inventory slot 15 and put 1 in slot 1, returning true, if not return false
function findBook()
    if turtle.getItemCount(15)>=1 then
        turtle.select(15)
        turtle.transferTo(1,1)
        turtle.select(1)
        return true
    else
        return false
    end
end

-- enchant the book in slot one and drop it into the chest underneath the turtle
function enchantBook(nLvl)
    if m.enchant(nLvl) then
        turtle.dropDown()
    else
        error("Unexpected error while trying to enchant")
    end
    
end

-- End program with a message

function exitMsg(exitNr)
    if exitNr == 1 then exitStr="Out of fuel. Place more fuel in slot 16 and restart the program"
    elseif exitNr == 2 then exitStr="No more items or books"
--    elseif exitNr == 3 then exitStr=""
--    elseif exitNr == 4 then exitStr=""
--    elseif exitNr == then exitStr=""
    
    end
    term.clear()
    term.setCursorPos(2,2)
    sleep(0.5)
    print(exitStr)
    run.state="end"
end



function printIntro()
    term.clear()
    print("---------------------------------------")
    print("------- XPturtle 0.2 by Gili710 -------")
    print("---------------------------------------")
    print()
    print("This turtle will automatically enchant items in its inventory")
    print("Place any items in slots 2 through 14")
    print("Place some books in slot 15.")
    print("Place some fuel in slot 16")
    print("Press any key to start")
    print()

end

function printStatus(curTask, curLvl)
    term.clear()
    term.setCursorPos(1,1)
    print("------- XPturtle 0.2 by Gili710 -------")
    term.setCursorPos(2,4)
    io.write(string.format("Current Task: %s", curTask))
    term.setCursorPos(2,6)
    io.write(string.format("Current Level: %s", curLvl))
end


--INIT
m=peripheral.wrap("right")
m.setAutoCollect(true)
nLvl=30
run = {}
run.state="running"
screenw, screenh = term.getSize()

-- Main Program

printIntro()
os.pullEvent()
checkFuel()
if run.state=="running" then
    moveToStart()
end



-- start main loop
while run.state=="running" do
    while not checkLevel(nLvl) do
        sleep(1)

    end
    checkFuel()
    loadState()

    --    Extra safety here
    while moveState ~= 5 do
        moveToStart()
        moveBack(5)
    end
    printStatus("enchanting", getLvl())
    sleep(2)
    if getItems() then
        enchantBook(nLvl)
        sleep(2)
        moveForward(5)
    else
        exitMsg(2)
    end
end