Turtlefarm 4 NF/DP

if not fs.exists("/.persistance") then
    print("Persistant variable folder not found. \n Creating...")
    fs.makeDir("/.persistance")
    print("Created")
end

function store(sName, stuff)
    local filePath = fs.combine("/.persistance", sName)
    if stuff == nil then
        return fs.delete(filePath)
    end
    local handle = fs.open(filePath, "w")
    handle.write(textutils.serialize(stuff))
    handle.close()
end

function pull(sName)
    local filePath = fs.combine("/.persistance", sName)
    local handle = fs.open(filePath, "r")
    local stuff = handle.readAll()
    handle.close()
    return textutils.unserialize(stuff)
end

if not fs.open(".persistance/farmCoords", "r") then
    coords = { }
    coords["x"] = 0
    coords["y"] = 0
    store("farmCoords", coords)
else
    coords = pull("farmCoords")
end
if not fs.open(".persistance/farmDir", "r") then
    direction = "north"
    store("farmDir", direction)
else
    direction = pull("farmDir")
end

if coords["x"] == 0 and coords["y"] == 0 then
    local success, idtable = turtle.inspectDown()
    if success and idtable.name == "minecraft:chest" then
        print("Home chest found")
    else
        error("Need chest below turtle to start farming!")
    end
end

--local fuelTC = 0

--[[function testForAvailableFuel()
    for i = 1, 16 do
        turtle.select(i)
        if turtle.refuel(0) then
            return true
        end
    end
    return false
end

function fuelTestCount()
    if fuelTC > 10 then
        fuelTC = fuelTC + 1
    else
        fuelTC = 0
        fuel()
    end
end


function fuel()
    local fLimit = turtle.getFuelLimit()
    local fCurr = turtle.getFuelLevel()
    local fSucc = testForAvailableFuel()
    if fCurr >= 5000 then return end
    if fCurr <= math.floor(fLimit/2) and fSucc == true then
        for i = 1, 16 do
            turtle.select(i)
            if turtle.refuel(0) then
                local halfStack = math.floor(turtle.getItemCount(i)/2)
                turtle.refuel(halfStack)
            end
        end
    end
end]]

function forward(dirToGo)
    if dirToGo == "north" then
        coords["y"] = coords["y"] + 1
        if direction == "north" then
            turtle.forward()
        elseif direction == "south" then
            turtle.turnLeft()
            turtle.turnLeft()
            turtle.forward()
        elseif direction == "west" then
            turtle.turnRight()
            turtle.forward()
        elseif direction == "east" then
            turtle.turnLeft()
            turtle.forward()
        end
        store("farmCoords", coords)
        direction = "north"
        store("farmDir", direction)
    elseif dirToGo == "east" then
        coords["x"] = coords["x"] + 1
        if direction == "north" then
            turtle.turnRight()
            turtle.forward()
        elseif direction == "west" then
            turtle.turnLeft()
            turtle.turnLeft()
            turtle.forward()
        elseif direction == "east" then
            turtle.forward()
        elseif direction == "south" then
            turtle.turnLeft()
            turtle.forward()
        end
        store("farmCoords", coords)
        direction = "east"
        store("farmDir", direction)
    elseif dirToGo == "south" then
        coords["y"] = coords["y"] - 1
        if direction == "south" then
            turtle.forward()
        elseif direction == "north" then
            turtle.turnLeft()
            turtle.turnLeft()
            turtle.forward()
        elseif direction == "east" then
            turtle.turnRight()
            turtle.forward()
        elseif direction == "west" then
            turtle.turnLeft()
            turtle.forward()
        end
        store("farmCoords", coords)
        direction = "south"
        store("farmDir", direction)
    elseif dirToGo == "west" then
        coords["x"] = coords["x"] - 1
        if direction == "west" then
            turtle.forward()
        elseif direction == "east" then
            turtle.turnLeft()
            turtle.turnLeft()
            turtle.forward()
        elseif direction == "south" then
            turtle.turnRight()
            turtle.forward()
        elseif direction == "north" then
            turtle.turnLeft()
            turtle.forward()
        end
        store("farmCoords", coords)
        direction = "west"
        store("farmDir", direction)
    end
    --fuelTestCount()
end

function moveTo(x2, y2)
    if x2 > coords["x"] then
        local x3 = x2 - coords["x"]
        for f = 1, x3 do
            forward("east")
        end
    elseif x2 < coords["x"] then
        local x3 = math.abs((math.abs(x2)) - coords["x"])
        for f = 1, x3 do
            forward("west")
        end
    end
    if y2 > coords["y"] then
        local y3 = y2 - coords["y"]
        for g = 1, y3 do
            forward("north")
        end
    elseif y2 < coords["y"] then
        local y3 = math.abs((math.abs(y2)) - coords["y"])
        for g = 1, y3 do
            forward("south")
        end
    end
end

function faceTo(dirToTurn)
    if dirToTurn == "north" then
        if direction == "south" then
            for i = 1, 2 do turtle.turnRight() end
        elseif direction == "east" then
            turtle.turnLeft()
        elseif direction == "west" then
            turtle.turnRight()
        end
        direction = "north"
        store("farmDir", direction)
    elseif dirToTurn == "south" then
        if direction == "north" then
            for i = 1, 2 do turtle.turnRight() end
        elseif direction == "east" then
            turtle.turnRight()
        elseif direction == "west" then
            turtle.turnLeft()
        end
        direction = "south"
        store("farmDir", direction)
    elseif dirToTurn == "east" then
        if direction == "west" then
            for i = 1, 2 do turtle.turnRight() end
        elseif direction == "north" then
            turtle.turnRight()
        elseif direction == "south" then
            turtle.turnLeft()
        end
        direction = "east"
        store("farmDir", direction)
    elseif dirToTurn == "west" then
        if direction == "east" then
            for i = 1, 2 do turtle.turnRight() end
        elseif direction == "north" then
            turtle.turnLeft()
        elseif direction == "south" then
            turtle.turnRight()
        end
        direction = "west"
        store("farmDir", direction)
    end
end

function dropOff()
    moveTo(0,0)
    faceTo("south")
    for i = 1, 16 do
        turtle.select(i)
        turtle.dropDown()
    end
    turtle.select(1)
    turtle.suck()
end

function findSeeds()
    for i = 1, 16 do
        turtle.select(i)
        local data = turtle.getItemDetail()
        if data then
            if data.name == "minecraft:wheat_seeds" then
                return i
            end
        end
    end
end

function harvestGrownAndPlant()
    local under, wheatCheck = turtle.inspectDown()
    if under then
        if wheatCheck.name == "minecraft:wheat" and wheatCheck.state.age == 7 then
            turtle.digDown()
            if not tonumber(findSeeds()) then return end
            local seeds = tonumber(findSeeds())
            if seeds then
                turtle.select(seeds)
                turtle.placeDown()
            else
                dropOff()
            end
        end
    else
        local seeds = tonumber(findSeeds())
        if seeds then
            turtle.select(seeds)
            turtle.placeDown()
        else
            dropOff()
        end
    end
end

function harvestAll()
    for k = 0, 26 do
        for p = 1, 28 do
            moveTo(k, p)
            harvestGrownAndPlant()
        end
    end
    moveTo(0,0)
end

moveTo(0,0)
faceTo("north")

while true do
    dropOff()
    harvestAll()
    sleep(600)
end