farmer

local countdown = 900;
local pos = {["x"]=0, ["y"]=0, ["z"]=0, ["r"]=1};
local slot = {};
for i = 1, 16, 1 do
    table.insert(slot, {["state"]="empty"});
end






function save()
    local file = fs.open("farmer","w");
        file.writeLine(string.gsub(textutils.serialize(pos),"\n%S-",""));
        file.writeLine(string.gsub(textutils.serialize(slot),"\n%S-",""));
        file.writeLine(countdown);
    file.close();
end

function load()
    if not fs.exists("farmer") then return end
    local file = fs.open("farmer","r")
        pos = textutils.unserialize(file.readLine())
        slot = textutils.unserialize(file.readLine())
        countdown = tonumber(file.readLine());
    file.close();
end

function turnLeft()
    if (pos.r == 0) then
        pos.r = 3;
    else
        pos.r = pos.r - 1;
    end
    save();
    turtle.turnLeft();
end

function turnRight()
    pos.r = (pos.r + 1) % 4;
    save();
    turtle.turnRight();
end

function rotate(r)
    while (not (pos.r == r)) do
        if (r == pos.r-1 or (r == 3 and pos.r == 0)) then
            turnLeft();
        elseif (r == pos.r+1 or (r == 0 and pos.r == 3)) then
            turnRight();
        elseif math.ceil(math.random()) < 0.5 then
            turnLeft()
        else
            turnRight();
        end
    end
end

function forward(l)
    for i = 1, l do
        if (pos.r == 0) then
            pos.y = pos.y + 1;
        elseif (pos.r == 1) then
            pos.x = pos.x + 1;
        elseif (pos.r == 2) then
            pos.y = pos.y - 1;
        elseif (pos.r == 3) then
            pos.x = pos.x - 1;
        end
        save();
        while not turtle.forward() do
            os.sleep(1);
        end
    end
end

function up()
    pos.z = pos.z + 1;
    save();
    while not turtle.up() do
        os.sleep(1);
    end
end

function down()
    pos.z = pos.z - 1;
    save();
    while not turtle.down() do
        os.sleep(1);
    end
end


function moveToField()
    if not (pos.x == 0 and pos.y == 0 and pos.z == 0 and pos.r == 1) then os.shutdown(); end
    rotate(3);
    forward(1);
    for i = 1, 7 do
        up();
    end
    rotate(1);
    foward(7);
    rotate(0);
    forward(22);
    rotate(1);
    forward(3);
    rotate(0);
    for i = 1, 3 do
        down();
    end
end

function moveToBase()
    forward(4);
    rotate(2);
    forward(22);
    rotate(3);
    forward(7);
    rotate(1);
    for i = 1, 7 do
        down();
    end
    forward(1);
    for s = 1, 16 do
        turtle.select(s);
        turtle.drop();
    end
end

function harvestPlant()
    turtle.select(1);
    if turtle.detectDown() then
        turtle.digDown();
        for s = 1, 2 do
            local itemdata = turtle.getItemDetail(s);
            if (string.match(itemdata.name, "seed")) then
                turtle.select(s);
                turtle.placeDown();
                break;
            end
        end
        for s = 1, 2 do
            turtle.select(s);
            turtle.transferTo(3);
        end
    end
end

function dropSeeds()
    for s = 1, 16 do
        local itemdata = turtle.getItemDetail(s);
        if (string.match(itemdata.name, "seed")) then
            turtle.select(s);
            turtle.drop();
            break;
        end
    end
end

function harvest()
    moveToField();
    turtle.select(1);
    for i = 1, 4 do
        for j = 1, 16 do
            harvestPlant();
            forward(1);
        end
        rotate(3);
        forward(1);
        rotate(2);
        for j = 1, 16 do
            harvestPlant();
            forward(1);
        end
        if (i < 4) then
            rotate(3);
            forward(1);
            rotate(0);
        end
    end
    rotate(3);
    dropSeeds();
    rotate(1);
    moveToBase();
end


function countDown()
    while (true) do
        if (countdown > 0) then
            print(countdown);
            os.sleep(30);
            countdown = countdown - 30;
            save();
        else
            harvest();
            countdown = 900;
            save();
        end
    end
end

load();
countDown();