farm.lua

local length = 18
local width = 18

local fuel_slot = 1
local fuel_minimum = length*width+length+width+10
local seed_slot = 2
local seconds_to_wait = 600
local wait_first = false
local deposit = false
local deposit_direction = 3

local b = false
local block = nil
local farming = true
local turn_adjust = 1
os.loadAPI("grey_api/move.lua")
os.loadAPI("grey_api/util.lua")

function farm_wheat(length,width)
    if length==nil then length=9 end--length is the forward size of the wheat plot
    if width==nil then width=9 end--width is the right size of the wheat plot
    turn_adjust = 1-- 1=+x, -1=-x

    while farming do
        harvest_wheat()
        if move.get_x() >= length-1 and turn_adjust == 1 then
            if move.get_z() >= width-1 then
                move.return_to_home()
                end_run()
            else
                move.turn("right")
                move.go()
                harvest_wheat()
                move.turn("right")
                move.go()
                turn_adjust = turn_adjust * -1
            end
        elseif move.get_x() <= 0 and turn_adjust == -1 then
            if move.get_z() >= width-1 then
                move.return_to_home()
                end_run()
            else
                move.turn("left")
                move.go()
                harvest_wheat()
                move.turn("left")
                move.go()
                turn_adjust = turn_adjust * -1
            end
        else
            if not move.go() then
                return false
            end
        end
    end--end while farming
end

function end_run()
    if deposit then deposit() end
    util.wait(seconds_to_wait)
    turn_adjust = 1
    print("wait done")
end

function deposit()
    local item = nil
    move.face(deposit_direction)
    for i=1,16 do
        item = turtle.getItemDetail(i)
        if item ~= nil and (item["name"]=="minecraft:wheat_seeds" or item["name"]=="minecraft:wheat") then
            --print("dropped "..item["name"].. " from slot "..i)
            turtle.select(i)
            turtle.drop()
        end
    end
    move.face(0)
end

function harvest_wheat()
    b,block = turtle.inspectDown()
    if b == false then
        --print("No block at ("..move.get_x()..","..move.get_z()..")")
        find_seed_slot()
        turtle.select(seed_slot)
        if not turtle.placeDown() then
            print("unplantable block at ("..move.get_x()..","..move.get_z()..")")
        end
    elseif block['state']['age']==7 then
        turtle.digDown()
        --print("Harvested at ("..move.get_x()..","..move.get_z()..")")
        find_seed_slot()
        turtle.select(seed_slot)
        turtle.placeDown()
    else
        --print("age!=7 at ("..move.get_x()..","..move.get_z()..")")
    end

    if turtle.getFuelLevel() <= fuel_minimum then
        util.fuel(1)
    end
end

function find_seed_slot()
    for i=1,16 do
        local item = turtle.getItemDetail(i)
        if item ~= nil and item["name"] == "minecraft:wheat_seeds" then
            seed_slot = i
            return i
        end
    end
    return 0
end

if wait_first then
    util.wait(seconds_to_wait)
end
farm_wheat(length,width)