N = 9
M = 14

-- END CONFIG SECTION

seeds_count  = 0
MAX_ITEMS    = 64

for i=2,16 do
    if turtle.compareTo(i) then
        seeds_count = seeds_count + turtle.getItemCount(i)
    end
end

if seeds_count-16 < N*M then
    printError("Not enough seeds!")
    -- return
end

args = ...

turtle.refuel(64)

function reset_out()
    redstone.setOutput("left", false)
    redstone.setOutput("right", false)
end

function harvest_complete(rotation)
    if rotation == turtle.turnRight then
        redstone.setOutput("left", true)
    else
        redstone.setOutput("right", true)
    end
    os.sleep(1)
end

function operation(forwarded, x, y)
    -- adding to the firtst slot seeds
    if turtle.getItemCount(1) == 1 then
        for i=2,16 do
            if turtle.compareTo(i) then
                available_items = turtle.getItemCount(i)
                if available_items == MAX_ITEMS then
                    available_items = available_items - 1
                end
                turtle.transferTo(1, available_items)
            end
        end
    end
    turtle.digDown()
    turtle.placeDown()
end

-- function defenitions
function check_start(delay)
    while true do
        if redstone.getInput("back") == true then
            -- go_to_house()
            return
        else
            os.sleep(delay)
        end
    end
end

function go_to_house()
    os.sleep(2)
    -- checking position of end harvest
    if M%2 == 0 then
        -- we at the same line
        -- turtle.back()
        turtle.turnRight()
        for i=1,M do
            turtle.forward()
        end
        turtle.turnLeft()

    else
        -- we at opposite line
        turtle.back()
        turtle.turnLeft()
        for i=1,M+1 do
            turtle.forward()
        end
        turtle.turnRight()
        for i=1,N+1 do
            turtle.forward()
        end
        turtle.turnRight()
        turtle.forward()
        turtle.turnRight()
    end
end

function run()
    return turtle.forward()
end

function harvest()
    local i = 0
    while i<M do
        j=0
        while j<N-1 do
            if run() then
                operation(true, i, j)
            else
                operation(false, i, j)
                j=j-1
            end
            turtle.dig()
            j=j+1
        end

        if i%2 == 0 then
            rotation = turtle.turnLeft
        else
            rotation = turtle.turnRight
        end

        rotation()

        if run() then
            operation(true, i,j)
        else
            operation(false, i,j)
            run()
        end

        rotation()
        i=i+1

    end

    reset_out()
    harvest_complete(rotation)
end



check_start(0.5)
harvest()
go_to_house()