local function has_locked_furnace_privilege(meta, player)
    if  player:get_player_name() ~= meta:get_string ("owner") and
        player:get_player_name() ~= minetest.setting_get ("name") then
        return false
    end
    return true
end

function default.furnace_active(pos, percent, item_percent)
    local formspec =
    "size[8,8.5]"..
    default.gui_bg..
    default.gui_bg_img..
    default.gui_slots..
    "list[current_name;src;2.75,0.5;1,1;]"..
    "list[current_name;fuel;2.75,2.5;1,1;]"..
    "image[2.75,1.5;1,1;default_furnace_fire_bg.png^[lowpart:"..
    (100-percent)..":default_furnace_fire_fg.png]"..
        "image[3.75,1.5;1,1;gui_furnace_arrow_bg.png^[lowpart:"..
        (item_percent*100)..":gui_furnace_arrow_fg.png^[transformR270]"..
    "list[current_name;dst;4.75,0.96;2,2;]"..
    "list[current_player;main;0,4.25;8,1;]"..
    "list[current_player;main;0,5.5;8,3;8]"..
    default.get_hotbar_bg(0,4.25)
    return formspec
  end

function default.get_furnace_active_formspec(pos, percent)
    local meta = minetest.get_meta(pos)local inv = meta:get_inventory()
    local srclist = inv:get_list("src")
    local cooked = nil
    local aftercooked = nil
    if srclist then
        cooked, aftercooked = minetest.get_craft_result({method = "cooking", width = 1, items = srclist})
    end
    local item_percent = 0
    if cooked then
        item_percent = meta:get_float("src_time")/cooked.time
    end

        return default.furnace_active(pos, percent, item_percent)
end

default.furnace_inactive_formspec =
    "size[8,8.5]"..
    default.gui_bg..
    default.gui_bg_img..
    default.gui_slots..
    "list[current_name;src;2.75,0.5;1,1;]"..
    "list[current_name;fuel;2.75,2.5;1,1;]"..
    "image[2.75,1.5;1,1;default_furnace_fire_bg.png]"..
    "image[3.75,1.5;1,1;gui_furnace_arrow_bg.png^[transformR270]"..
    "list[current_name;dst;4.75,0.96;2,2;]"..
    "list[current_player;main;0,4.25;8,1;]"..
    "list[current_player;main;0,5.5;8,3;8]"..
    default.get_hotbar_bg(0,4.25)

minetest.register_node("default:furnace_locked", {
    description = "Locked Furnace",
    tiles = {"default_furnace_top.png", "default_furnace_bottom.png", "default_furnace_side.png",
        "default_furnace_side.png", "default_furnace_side.png", "default_furnace_locked_front.png"},
    paramtype2 = "facedir",
    groups = {cracky=2},
    legacy_facedir_simple = true,
    is_ground_content = false,
    sounds = default.node_sound_stone_defaults(),

    after_place_node = function(pos, placer)
        local meta = minetest.get_meta(pos)
        meta:set_string("owner", placer:get_player_name())
        meta:set_string("infotext", "Locked Furnace (owned by " .. placer:get_player_name() .. ")")
    end ,

    on_construct = function(pos)
        local meta = minetest.get_meta(pos)
        meta:set_string("formspec", default.furnace_inactive_formspec)
        meta:set_string("infotext", "Furnace")
        local inv = meta:get_inventory()
        inv:set_size("fuel", 1)
        inv:set_size("src", 1)
        inv:set_size("dst", 4)
    end,

    can_dig = function(pos,player)
        local meta = minetest.get_meta(pos)
        local inv = meta:get_inventory()

        if not has_locked_furnace_privilege (meta, player) then
            return false
        end

        if not inv:is_empty("fuel") then
            return false
        elseif not inv:is_empty("dst") then
            return false
        elseif not inv:is_empty("src") then
            return false
        end
        return true
    end,

    allow_metadata_inventory_put = function(pos, listname, index, stack, player)
        local meta = minetest.get_meta(pos)
        if not has_locked_furnace_privilege (meta, player) then
            minetest.log ("action", player:get_player_name() ..
                " tried to access a locked furnace belonging to "..
                meta:get_string ("owner").." at "..
                minetest.pos_to_string (pos) .. ".")
            return 0
        end

        local inv = meta:get_inventory()
        if listname == "fuel" then
            if minetest.get_craft_result({method="fuel",width=1,items={stack}}).time ~= 0 then
                if inv:is_empty("src") then
                    meta:set_string("infotext","Furnace is empty")
                end
                return stack:get_count()
            else
                return 0
            end
        elseif listname == "src" then
            return stack:get_count()
        elseif listname == "dst" then
            return 0
        end
    end,

    allow_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player)
        local meta = minetest.get_meta(pos)
        if not has_locked_furnace_privilege (meta, player) then
            minetest.log ("action", player:get_player_name() ..
                " tried to access a locked furnace belonging to "..
                meta:get_string ("owner").." at "..
                minetest.pos_to_string (pos) .. ".")
            return 0
        end

        local inv = meta:get_inventory()
        local stack = inv:get_stack(from_list, from_index)
        if to_list == "fuel" then
            if minetest.get_craft_result({method="fuel",width=1,items={stack}}).time ~= 0 then
                if inv:is_empty("src") then
                    meta:set_string("infotext","Furnace is empty")
                end
                return count
            else
                return 0
            end
        elseif to_list == "src" then
            return count
        elseif to_list == "dst" then
            return 0
        end
    end,

    allow_metadata_inventory_take = function(pos, listname, index, stack, player)
        local meta = minetest.get_meta(pos)
        if not has_locked_furnace_privilege(meta, player) then
            minetest.log ("action", player:get_player_name() ..
                " tried to access a locked furnace belonging to " ..
                meta:get_string("owner").." at "..
                minetest.pos_to_string(pos) .. ".")
            return 0
        end
        return stack:get_count()
    end,
})

minetest.register_node("default:furnace_locked_active", {
    description = "Locked Furnace" ,
    tiles = {
        "default_furnace_top.png",
        "default_furnace_bottom.png",
        "default_furnace_side.png",
        "default_furnace_side.png",
        "default_furnace_side.png",
        {
            image = "default_furnace_locked_front_active.png",
            backface_culling = false,
            animation = {
                type = "vertical_frames",
                aspect_w = 16,
                aspect_h = 16,
                length = 1.5
            },
        }
    },
    paramtype2 = "facedir",
    light_source = 8,
    drop = "default:furnace_locked",
    groups = {cracky=2, not_in_creative_inventory=1,hot=1},
    legacy_facedir_simple = true,
    is_ground_content = false,
    sounds = default.node_sound_stone_defaults(),
    on_construct = function(pos)
        local meta = minetest.get_meta(pos)
        meta:set_string("formspec", default.furnace_inactive_formspec)
        meta:set_string("infotext", "Furnace");
        local inv = meta:get_inventory()
        inv:set_size("fuel", 1)
        inv:set_size("src", 1)
        inv:set_size("dst", 4)
    end,

    can_dig = function(pos,player)
        local meta = minetest.get_meta(pos)
        local inv  = meta:get_inventory()

        if not has_locked_furnace_privilege (meta, player) then
            return false
        end

        if not inv:is_empty("fuel") then
            return false
        elseif not inv:is_empty("dst") then
            return false
        elseif not inv:is_empty("src") then
            return false
        end
        return true
    end,

    allow_metadata_inventory_put = function(pos, listname, index, stack, player)
        local meta = minetest.get_meta(pos)
        if not has_locked_furnace_privilege (meta, player) then
            minetest.log ("action", player:get_player_name() ..
                " tried to access a locked furnace belonging to "..
                meta:get_string ("owner").." at "..
                minetest.pos_to_string (pos) .. ".")
            return 0
        end

        local inv = meta:get_inventory()
        if listname == "fuel" then
            if minetest.get_craft_result({method="fuel",width=1,items={stack}}).time ~= 0 then
                if inv:is_empty("src") then
                    meta:set_string("infotext","Furnace is empty")
                end
                return stack:get_count()
            else
                return 0
            end
        elseif listname == "src" then
            return stack:get_count()
        elseif listname == "dst" then
            return 0
        end
    end,

    allow_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player)
        local meta = minetest.get_meta(pos)
        if not has_locked_furnace_privilege (meta, player) then
            minetest.log ("action", player:get_player_name() ..
                " tried to access a locked furnace belonging to "..
                meta:get_string ("owner").." at "..
                minetest.pos_to_string (pos) .. ".")
            return 0
        end

        local inv = meta:get_inventory()
        local stack = inv:get_stack(from_list, from_index)
        if to_list == "fuel" then
            if minetest.get_craft_result({method="fuel",width=1,items={stack}}).time ~= 0 then
                if inv:is_empty("src") then
                    meta:set_string("infotext","Furnace is empty")
                end
                return count
            else
                return 0
            end
        elseif to_list == "src" then
            return count
        elseif to_list == "dst" then
            return 0
        end
    end,

    allow_metadata_inventory_take = function(pos, listname, index, stack, player)
        local meta = minetest.get_meta(pos)
        if not has_locked_furnace_privilege(meta, player) then
            minetest.log ("action", player:get_player_name() ..
                " tried to access a locked furnace belonging to " ..
                meta:get_string("owner").." at "..
                minetest.pos_to_string(pos) .. ".")
            return 0
        end
        return stack:get_count()
    end,
})

local function swap_node(pos,name)
    local node = minetest.get_node(pos)
    if node.name == name then
        return
    end
    node.name = name
    minetest.swap_node(pos,node)
end

minetest.register_abm ({
    nodenames = {"default:furnace_locked","default:furnace_locked_active"},
    interval  = 1.0   ,
    chance    = 1     ,
    catch_up  = false ,

    action = function(pos, node, active_object_count, active_object_count_wider)
        local meta = minetest.get_meta(pos)

        if meta == nil or
           meta:get_string ("formspec") == "" or
           meta:get_string ("formspec") == nil then
            meta:set_string ("formspec", default.furnace_inactive_formspec)
            meta:set_string ("infotext", "Furnace")
            local inv = meta:get_inventory()
            inv:set_size ("fuel" , 1)
            inv:set_size ("src"  , 1)
            inv:set_size ("dst"  , 4)
        end

        for i, name in ipairs({
                "fuel_totaltime",
                "fuel_time",
                "src_totaltime",
                "src_time"
        }) do
            if meta:get_string(name) == "" then
                meta:set_float(name, 0.0)
            end
        end

        local inv = meta:get_inventory()

        local srclist = inv:get_list("src")
        local cooked = nil
        local aftercooked

        if srclist then
            cooked, aftercooked = minetest.get_craft_result({method = "cooking", width = 1, items = srclist})
        end

        local was_active = false

        if meta:get_float("fuel_time") < meta:get_float("fuel_totaltime") then
            was_active = true
            meta:set_float("fuel_time", meta:get_float("fuel_time") + 1)
            meta:set_float("src_time", meta:get_float("src_time") + 1)
            if cooked and cooked.item and meta:get_float("src_time") >= cooked.time then
                -- check if there's room for output in "dst" list
                if inv:room_for_item("dst",cooked.item) then
                    -- Put result in "dst" list
                    inv:add_item("dst", cooked.item)
                    -- take stuff from "src" list
                    inv:set_stack("src", 1, aftercooked.items[1])
                else
                    --print("Could not insert '"..cooked.item:to_string().."'")
                end
                meta:set_string("src_time", 0)
            end
        end

        if meta:get_float("fuel_time") < meta:get_float("fuel_totaltime") then
            local percent = math.floor(meta:get_float("fuel_time") /
                    meta:get_float("fuel_totaltime") * 100)
            meta:set_string("infotext","Furnace active: "..percent.."%")
            swap_node(pos,"default:furnace_locked_active")
            meta:set_string("formspec",default.get_furnace_active_formspec(pos, percent))
            return
        end

        local fuel = nil
        local afterfuel
        local cooked = nil
        local fuellist = inv:get_list("fuel")
        local srclist = inv:get_list("src")

        if srclist then
            cooked = minetest.get_craft_result({method = "cooking", width = 1, items = srclist})
        end
        if fuellist then
            fuel, afterfuel = minetest.get_craft_result({method = "fuel", width = 1, items = fuellist})
        end

        if not fuel or fuel.time <= 0 then
            meta:set_string("infotext","Furnace out of fuel")
            swap_node(pos,"default:furnace_locked")
            meta:set_string("formspec", default.furnace_inactive_formspec)
            return
        end

        if cooked.item:is_empty() then
            if was_active then
                meta:set_string("infotext","Furnace is empty")
                swap_node(pos,"default:furnace_locked")
                meta:set_string("formspec", default.furnace_inactive_formspec)
            end
            return
        end

        meta:set_string("fuel_totaltime", fuel.time)
        meta:set_string("fuel_time", 0)

        inv:set_stack("fuel", 1, afterfuel.items[1])
    end,
})