COMPUTERCRAFT: Potato Farmer

farm.lua

START_X = 109
START_Y = 57
START_Z = 769

FARM_X_END_EVEN = 108
FARM_X_END_ODD = 97
FARM_Z_START = 769
FARM_Z_END = 782

NUM_SLOTS = 16

current_dir = 0
dirs = { "XNEG", "ZNEG", "XPOS", "ZPOS" }

function find_dir()
    local x,y,z = gps.locate()

    for i = 1, 4, 1 do
        found_block, data = turtle.inspect()

        if not found_block or data["name"] == "minecraft:potato" then
            forward()
            break
        else
            turtle.turnLeft()
        end
    end

    local nx,ny,nz = gps.locate()

    if (nx > x) then
        current_dir = 3
    elseif (nx < x) then
        current_dir = 1
    elseif (nz > z) then
        current_dir = 4
    elseif (nz < z) then
        current_dir = 2
    else
        -- try again
        find_dir()
    end
end

function is_col_odd()
    if find_col() % 2 == 0 then return false end
    return true
end

function turn_left()
    local success = turtle.turnLeft()

    if success then
        current_dir = current_dir - 1
        if (current_dir < 1) then current_dir = 4 end
    end

    return success
end

function turn_right()
    local success = turtle.turnRight()

    if success then
        current_dir = current_dir + 1
        if (current_dir > 4) then current_dir = 1 end
    end

    return success
end

function forward()
    turtle.forward()
    found_block, data = turtle.inspectDown()
    if found_block and data["name"] == "minecraft:potatoes" and data["state"]["age"] >= 7 then
        turtle.digDown()
        turtle.placeDown()
    end
end

function succ()
    turtle.suckUp()
    turtle.suck()
    turtle.suckDown()
end

function get_dir()
    return dirs[current_dir]
end

function turn_to_face(dir)
    for i = 0, 4, 1 do
        if (current_dir == dir) then return end
        turn_left()
    end
end

function find_col()
    x,y,z = gps.locate()
    return z - FARM_Z_START + 1
end

function is_last_row()
    local col = find_col()
    if (col == FARM_Z_END - FARM_Z_START + 1) then 
        return true 
    end
    return false
end

function move_to_x(nx)
    local x,y,z = gps.locate()
    if (x == nx) then return end

    if (nx > x) then 
        turn_to_face(3) 
    else
        turn_to_face(1)
    end

    for i = 0, math.abs(nx-x)-1, 1 do
        forward()
    end    
end

function move_to_z(nz)
    local x,y,z = gps.locate()
    if (z == nz) then return end

    if (nz > z) then 
        turn_to_face(4) 
    else
        turn_to_face(2)
    end

    for i = 0, math.abs(nz-z)-1, 1 do
        forward()
    end    
end

function deposit()
    for i = 1, NUM_SLOTS, 1 do
        turtle.select(i)

        local data = turtle.getItemDetail()
        if data and data["name"] == "minecraft:potato" then
            turtle.drop()
        end
    end

    turtle.select(1)
end

function refuel()
    while turtle.getFuelLevel() < 1000 do
        turtle.select(1)
        turtle.suckDown()
        turtle.refuel()
    end
end

function drop_remaining()
    for i = 1, NUM_SLOTS, 1 do
        turtle.select(i)
        turtle.dropDown()
    end

    turtle.select(1)
end

function is_on_farm()
    x,y,z = gps.locate()

    if x >= FARM_X_END_ODD and x <= FARM_X_END_EVEN and z >= FARM_Z_START and z <= FARM_Z_END then
        return true
    end

    return false
end

function empty_inventory()
    for i = 1, 16, 1 do
        turtle.select(i)
        turtle.refuel()
        turtle.dropUp()
    end

    turtle.select(1)
end

while true do
    find_dir()

    if not is_on_farm() then
        move_to_x(START_X)
        move_to_z(START_Z)
        refuel()
        empty_inventory()
        os.sleep(400)
    end

    while not is_last_row() do
        if is_col_odd() then
            move_to_x(FARM_X_END_ODD)
        else
            move_to_x(FARM_X_END_EVEN)
        end

        turn_to_face(4)
        forward()
    end

    move_to_x(FARM_X_END_EVEN+1)
    deposit()
    drop_remaining()
end