FTB Automatic Farm V 2.0

-- FTB AutomaticFarm - V 2.0
-- Made by Xmarks
-- https://www.youtube.com/channel/UCA6oAnFqdDcc0sa6H8G5DSA
-- Program Farms and Replants Seeds
-- Program ensures the operation can not be blocked
-- Program Drops Excess Inventory in a chest below when Operation is finished
-- *********************************
-- Fuel Goes to Slot 1
-- Seeds for comparison go to Slot 2
-- *********************************

-- Set Coordinates for where the Turtle will farm
x = 4
y = 4

-- Global Seed Slot Variable - Do not Change
seed_slot = 0

-- Local Function - Check Fuel Level - Refuel if necessary
-- TODO: Calculate Path and do not start if not enough for 1 Full Operation
local function checkFuel()
    if turtle.getFuelLevel() < 20 then
        turtle.select(1)
        turtle.refuel(1)
    end
end

-- Local Function - Ensure Turtle Moves Forward 1 Block
local function forward()
    checkFuel()
    counter = 0

    while counter < 1 do
        if turtle.forward() then
            counter = counter + 1
        -- If can not move, try digging and attacking
        else
            turtle.dig()
            turtle.attack()
        end
    end
end

-- Left U-Turn
local function goLeft()
    turtle.turnLeft()
    forward()
    turtle.turnLeft()
end

-- Right U-Turn
local function goRight()
    turtle.turnRight()
    forward()
    turtle.turnRight()
end

-- Function Tries to find seeds
local function findSeeds()
    for i = 3,16 do
        turtle.select(i)
        if turtle.compareTo(2) then
            return i
        end
    end
    -- if Seeds are not found - Reset to Slot 2
    return 2
end

-- Turtle Plows/Harvests & Plants Seeds
local function harvestReplant()

    turtle.digDown()

    -- Go to Saved Seed Slot if set during Operation
    if seed_slot ~= 0 then
        turtle.select(seed_slot)
    end

    -- If Seed Slot is not set
    -- If Seed Slot is the Comparison Slot
    -- If Saved Seed Slot Count is 0
    -- If Saved Seed Slot does not actually have Seeds
    if ( (seed_slot == 0) or (seed_slot == 2) or (turtle.getItemCount(seed_slot) == 0) or (turtle.compareTo(2) == false) ) then
        seed_slot = findSeeds()
        turtle.select(seed_slot)
    end

    turtle.placeDown()
end

-- Farming Function
-- Turtle will go around the set Matrix x/y
-- Plowing/Harvesting and Planting
local function farm()
    for i = 1,x do
        if i%2 == 1 then
            goLeft()

            for j =1,y do
                harvestReplant()
                if j ~= y then
                    forward()
                end
            end

        elseif i%2 == 0 then
            goRight()

            for j = 1,y do
                harvestReplant()
                if j ~= y then
                    forward()
                end
            end
        end
    end
end

-- Turns the Turtle back to Starting Position
-- Calculations based on the given Farm Matrix-Size x/y
local function returnHome()
    if x%2 == 0 then
        forward()
        turtle.turnRight()

        for i = 1,x do
            forward()
        end

    elseif x%2 == 1 then
        turtle.turnLeft()
        turtle.turnLeft()

        for j = 1,y do
            forward()
        end

        turtle.turnRight()

        for i = 1,x do
            forward()
        end
    end

    turtle.turnRight()
    forward()
    turtle.turnLeft()
    turtle.turnLeft()
end

-- Wait for Seeds to Grow Back - 35min
local function timeOut()
    for i = 2100,0,-1 do
        print('Waiting Seed Growth - ' .. i .. 'sec left')
        sleep(1)
    end
end

-- Drop Everything except Fuel and Comparison Seeds
local function dumpInventory()
    print('Dropping all blocks in slots 3-to-16 into a bottom chest')

    for slot = 3,16 do
        turtle.select(slot)
        turtle.dropDown()
    end
end

-- Farm/Return/Wait/Repeat
while true do
  farm()
  returnHome()
  dumpInventory()
  timeOut()
end