local SIZE_SMALL = 20;
local SIZE_LARGE = 40;
local SCALE_SMALL = 1;
local SCALE_LARGE = 4;

-- Draw background elements in the same arrangement as inventory slots
-- x: The x position of the inventory
-- y: The y position of the inventory
-- cols: The width of the inventory, in columns
-- rows: The height of the inventory, in rows
-- skin: A 9-slice background skin table
--
-- Returns a formspec string
local function inventory_bg(x, y, cols, rows, skin)
    local data = "";
    for i = 0,cols - 1 do
        for j = 0,rows - 1 do
            data = data .. string.format("background9[%f,%f;1,1;%s.png;false;%s]",
                                        x + (i * 1.25), y + (j * 1.25),
                                        skin.texture,
                                        tostring(skin.radius));
        end
    end

    return data;
end

local function get_material_cost(size, detail)
    local paper = 0;
    local pigment = 0;

    if size == SIZE_SMALL then
        paper = paper + 4;
        pigment = pigment + 5;
    elseif size == SIZE_LARGE then
        paper = paper + 16;
        pigment = pigment + 20;
    end

    pigment = pigment + (detail * 5);

    return {
        paper = math.max(paper, 0),
        pigment = math.max(pigment, 0),
    };
end

-- Get the material cost of the craft settings from the given table metadata
-- meta: The metadata to read
--
-- Returns a table with the material costs, and a boolean indicating if the
-- costs were positive or negative before clamping.
local function get_craft_material_cost(meta)
    local cost = get_material_cost(meta:get_int("size") or SIZE_SMALL, meta:get_int("detail") or 0);
    local stack = meta:get_inventory():get_stack("output", 1);
    local is_positive = true;

    if stack:get_name() == "cartographer:map" then
        local smeta = stack:get_meta();
        local sub_cost = get_material_cost(smeta:get_int("cartographer:size") or SIZE_SMALL, (smeta:get_int("cartographer:detail") or 1) - 1);
        is_positive = cost.paper >= sub_cost.paper and cost.pigment >= sub_cost.pigment;
        cost.paper = math.max(cost.paper - sub_cost.paper, 0);
        cost.pigment = math.max(cost.pigment - sub_cost.pigment, 0);
    end

    return cost, is_positive;
end

-- Check if the given table metadata has enough materials to cover the given
-- cost table.
-- cost: A table of material costs
-- meta: The metadata
--
-- Returns true if the table's materials can cover the cost
local function can_afford(cost, meta)
    return cost.paper + cost.pigment > 0
       and cost.paper <= meta:get_int("paper")
       and cost.pigment <= meta:get_int("pigment");
end

-- Get the material cost of the copy settings from the given table metadata
-- meta: The metadata to read
--
-- Returns a table with the material costs
local function get_copy_material_cost(meta)
    local inv = meta:get_inventory();
    local in_stack = inv:get_stack("copy_input", 1);
    local out_stack = inv:get_stack("copy_output", 1);


    if out_stack:is_empty() and in_stack:get_name() == "cartographer:map" then
        local smeta = in_stack:get_meta();
        local size = smeta:get_int("cartographer:size") or SIZE_SMALL;
        local detail = smeta:get_int("cartographer:detail") or 1;

        return get_material_cost(size, detail - 1);
    end

    return {
        paper = 0,
        pigment = 0,
    };
end

-- Get the converted material value of the given itemstack
-- stack: The itemstack to convert
--
-- Returns a table with the material values
function cartographer.get_material_value(stack)
    local item_name = stack:get_name();
    local item_count = stack:get_count();

    for name,mats in pairs(_cartographer.materials_by_name) do
        if name == item_name then
            return {
                paper = (mats.paper or 0) * item_count,
                pigment = (mats.pigment or 0) * item_count,
            }
        end
    end

    for group,mats in pairs(_cartographer.materials_by_group) do
        if minetest.get_item_group(item_name, group) ~= 0 then
            return {
                paper = (mats.paper or 0) * item_count,
                pigment = (mats.pigment or 0) * item_count,
            }
        end
    end

    return {
        paper = 0,
        pigment = 0,
    };
end

local fs = {};

-- Draw a button, with support for enabled/disabled states
-- x: The x position of the button
-- y: The y position of the button
-- w: The width of the button
-- h: The height of the button
-- id: The element id
-- text: The text to display in the button
-- enabled: Whether or not the button is enabled
--
-- Returns a formspec string
function fs.button(x, y, w, h, id, text, enabled)
    if enabled then
        return string.format("button[%f,%f;%f,%f;%s;%s]", x, y, w, h, id, text);
    end

    return string.format("button[%f,%f;%f,%f;disabled_button;%s]", x, y, w, h, text);
end

-- Draw a 1px thick horizontal separator formspec element
-- y: The y position of the separator
-- skin: A 9-slice background skin table
--
-- Returns a formspec string
function fs.separator(y, skin)
    return string.format("background9[0.1,%f;10.05,0.01;%s.png;false;%s]", y, skin.texture, tostring(skin.radius))
end

-- Draw all the essential formspec data (size, background, styles, tabs)
-- w: The width of the formspec
-- h: The height of the formspec
-- rank: An into defining the 'rank' of the table being displayed
-- tab: An int defining the index of the selected tab
-- skin: A formspec skin table
--
-- Returns a formspec string
function fs.header(w, h, rank, tab, skin)
    local data = "formspec_version[3]"
              .. string.format("size[%f,%f]", w, h)
              .. string.format("background9[-0.1,0;1,1;%s.png;true;%s]", skin.background.texture, tostring(skin.background.radius))
              .. string.format("background9[0.0625,0.125;%f,%f;%s.png;false;%s]", w - 0.125, h - 0.25, skin.inner_background.texture, tostring(skin.inner_background.radius))
              .. string.format("style_type[button;noclip=true;border=false;bgimg=%s.png;bgimg_hovered=%s.png;bgimg_pressed=%s.png;bgimg_middle=%s;textcolor=%s]", skin.tab.texture, skin.tab.hovered_texture, skin.tab.pressed_texture, tostring(skin.tab.radius), skin.tab.font_color)
              .. string.format("style[tab%d;noclip=true;border=false;bgimg=%s.png;bgimg_hovered=%s.png;bgimg_pressed=%s.png;bgimg_middle=%s;textcolor=%s]", tab, skin.tab.selected_texture, skin.tab.selected_texture, skin.tab.selected_texture, tostring(skin.tab.radius), skin.tab.font_color)
              .. string.format("button[0.25,-0.425;1.5,0.55;tab1;Materials]", tab)
              .. string.format("button[1.75,-0.425;1.5,0.55;tab2;Create Map]", tab);

    if rank >= 2 then
        data = data .. string.format("button[3.25,-0.425;1.5,0.55;tab3;Copy Map]", tab);
    end

    return data .. string.format("style_type[button;border=false;bgimg=%s.png;bgimg_hovered=%s.png;bgimg_pressed=%s.png;bgimg_middle=%s;textcolor=%s]", skin.button.texture, skin.button.hovered_texture, skin.button.pressed_texture, tostring(skin.button.radius), skin.button.font_color)
                .. string.format("style[disabled_button;bgimg=;bgimg_hovered=;bgimg_pressed=;textcolor=%s]", skin.button.disabled_font_color);
end

-- Draw material counters from a table's metadata
-- x: The x position of the labels
-- y: The y position of the labels
-- meta: A metadata object containing the material quantities
-- skin: A formspec skin table
--
-- Returns a formspec string
function fs.materials(x, y, meta, skin)
    return string.format("container[%f,%f]", x, y)
        .. "formspec_version[3]"
        .. string.format("background9[0,0.125;1,0.25;%s.png;false;%s]", skin.label.texture, tostring(skin.label.radius))
        .. string.format("image[0.125,0.125;0.25,0.25;%s.png]", skin.paper_texture)
        .. string.format("label[0.375,0.25;%sx %d]", minetest.get_color_escape_sequence(skin.label.font_color), meta:get_int("paper"))
        .. string.format("background9[1.25,0.125;1,0.25;%s.png;false;%s]", skin.label.texture, tostring(skin.label.radius))
        .. string.format("image[1.375,0.125;0.25,0.25;%s.png]", skin.pigment_texture)
        .. string.format("label[1.625,0.25;%sx %d]", minetest.get_color_escape_sequence(skin.label.font_color), meta:get_int("pigment"))
        .. "container_end[]";
end

-- Draw a label with material costs from a table
-- x: The x position of the interface
-- y: The y position of the interface
-- materials: A table of material costs, with string keys for the material
--            names and iteger values
-- skin: A formspec skin table
--
-- Returns a formspec string
function fs.cost(x, y, materials, skin)
    local data = "";
    local i = 0;

    for name,value in pairs(materials) do
        data = data .. string.format("label[%f,%f;%s%s x %d]", x, y + (i * 0.25), minetest.get_color_escape_sequence(skin.label.font_color), name, value);
        i = i + 1;
    end

    return data;
end

-- Draw the material conversion tab UI
-- x: The x position of the interface
-- y: The y position of the interface
-- pos: The table position (for displaying the inventory)
-- skin: A formspec skin table
--
-- Returns a formspec string
function fs.convert(x, y, pos, skin)
    local meta = minetest.get_meta(pos);
    local value = cartographer.get_material_value(meta:get_inventory():get_stack("input", 1));

    return string.format("container[%f,%f]", x, y)
        .. "formspec_version[3]"
        .. inventory_bg(0, 0, 1, 1, skin.slot)
        .. string.format("list[nodemeta:%d,%d,%d;input;0,0;1,1;]", pos.x, pos.y, pos.z)
        .. fs.button(1.25, 0.5, 2, 0.5, "convert", "Convert Materials", value.paper + value.pigment > 0)
        .. fs.cost(1.25, 0.125, value, skin)
        .. "container_end[]";
end

-- Draw the map crafting tab UI
-- x: The x position of the interface
-- y: The y position of the interface
-- pos: The table position (for displaying the inventory)
-- meta: A metadata object containing the table settings and material
--       quantities
-- skin: A formspec skin table
--
-- Returns a formspec string
function fs.craft(x, y, pos, rank, meta, skin)
    local cost, is_positive = get_craft_material_cost(meta);
    local data = string.format("container[%f,%f]", x, y)
              .. "formspec_version[3]"
              .. inventory_bg(0, 0.75, 1, 1, skin.slot)
              .. string.format("list[nodemeta:%d,%d,%d;output;0,0.75;1,1;]", pos.x, pos.y, pos.z)
              .. fs.button(1.25, 1.25, 2, 0.5, "craft", "Craft Map", is_positive and can_afford(cost, meta))
              .. fs.cost(1.25, 0.875, cost, skin);

    if rank > 1 then
        local size = "s";
        if meta:get_int("size") == SIZE_LARGE then
            size = "l";
        end

        data = data .. string.format("style[%s;bgimg=%s.png;bgimg_hovered=%s.png;bgimg_pressed=%s.png]", size, skin.button.selected_texture, skin.button.selected_texture, skin.button.selected_texture)
                    .. "button[0,0;0.5,0.5;s;S]"
                    .. "button[0.5,0;0.5,0.5;l;L]";
    end

    if rank > 2 then
        local scale = "1x";
        if meta:get_int("scale") == SCALE_LARGE then
            scale = "4x";
        end

        data = data .. string.format("style[%s;bgimg=%s.png;bgimg_hovered=%s.png;bgimg_pressed=%s.png]", scale, skin.button.selected_texture, skin.button.selected_texture, skin.button.selected_texture)
                    .. "button[3.5,0;0.5,0.5;1x;1x]"
                    .. "button[4.0,0;0.5,0.5;4x;4x]";
    end

    data = data .. string.format("style[%d;bgimg=%s.png;bgimg_hovered=%s.png;bgimg_pressed=%s.png]", meta:get_int("detail") + 1, skin.button.selected_texture, skin.button.selected_texture, skin.button.selected_texture)
                .. "button[1.25,0;0.5,0.5;1;1]"
                .. "button[1.75,0;0.5,0.5;2;2]";
    if rank > 1 then
        data = data .. "button[2.25,0;0.5,0.5;3;3]";
        if rank > 2 then
            data = data .. "button[2.75,0;0.5,0.5;4;4]";
        end
    end

    return data .. "container_end[]";
end

-- Draw the map copying tab UI
-- x: The x position of the interface
-- y: The y position of the interface
-- pos: The table position (for displaying the inventory)
-- skin: A formspec skin table
--
-- Returns a formspec string
function fs.copy(x, y, pos, skin)
    local meta = minetest.get_meta(pos);
    local costs = get_copy_material_cost(meta);

    return string.format("container[%f,%f]", x, y)
        .. "formspec_version[3]"
        .. inventory_bg(0, 0, 1, 1, skin.slot)
        .. string.format("list[nodemeta:%d,%d,%d;copy_input;0,0;1,1;]", pos.x, pos.y, pos.z)
        .. fs.button(1.25, 0.5, 2, 0.5, "copy", "Copy Map", can_afford(costs, meta))
        .. fs.cost(1.25, 0.125, costs, skin)
        .. inventory_bg(8.75, 0, 1, 1, skin.slot)
        .. string.format("list[nodemeta:%d,%d,%d;copy_output;8.75,0;1,1;]", pos.x, pos.y, pos.z)
        .. "container_end[]";
end

-- Draw the player's inventory
-- x: The x position of the inventory
-- y: The y position of the inventory
-- skin: A formspec skin table
--
-- Returns a formspec string
function fs.inv(x, y, skin)
    return string.format("container[%f,%f]", x, y)
        .. "formspec_version[3]"
        .. inventory_bg(0, 0, 8, 4, skin.slot)
        .. "list[current_player;main;0,0;8,4;]"
        .. "container_end[]";
end

local player_tables = {};

-- Show the table formspec to the specified player
-- The player must be recorded in player_tables in order to receive
-- a formspec.
--
-- player: The player's name
local function table_formspec(player)
    local data = player_tables[player];
    local pos = data.pos;

    if not pos then
        return;
    end

    local meta = minetest.get_meta(pos);

    local rank = 1;
    local skin = cartographer.skin.table_skins.simple_table;
    local name = minetest.get_node(pos).name;
    if name == "cartographer:standard_table" then
        rank = 2;
        skin = cartographer.skin.table_skins.standard_table;
    elseif name == "cartographer:advanced_table" then
        rank = 3;
        skin = cartographer.skin.table_skins.advanced_table;
    end

    if data.tab == 1 then
        minetest.show_formspec(player, "simple_table",
            fs.header(10.25, 7.375, rank, data.tab, skin) ..
            fs.materials(0.25, 0.1875, meta, skin) ..
            fs.separator(0.6875, skin.separator) ..
            fs.convert(0.25, 0.875, pos, skin) ..
            fs.separator(2.125, skin.separator) ..
            fs.inv(0.25, 2.375, skin)
            );
    elseif data.tab == 2 then
        minetest.show_formspec(player, "simple_table",
            fs.header(10.25, 8.0, rank, data.tab, skin) ..
            fs.materials(0.25, 0.1875, meta, skin) ..
            fs.separator(0.6875, skin.separator) ..
            fs.craft(0.25, 0.875, pos, rank, meta, skin) ..
            fs.separator(2.75, skin.separator) ..
            fs.inv(0.25, 3, skin)
            );
    elseif data.tab == 3 then
        minetest.show_formspec(player, "simple_table",
            fs.header(10.25, 7.375, rank, data.tab, skin) ..
            fs.materials(0.25, 0.1875, meta, skin) ..
            fs.separator(0.6875, skin.separator) ..
            fs.copy(0.25, 0.875, pos, skin) ..
            fs.separator(2.125, skin.separator) ..
            fs.inv(0.25, 2.375, skin)
            );
    end
end

-- Called when a player sends input to the server from a formspec
-- This callback handles player input in the table formspec
-- player: The player who sent the input
-- name: The formspec name
-- fields: A table containing the input
minetest.register_on_player_receive_fields(function(player, name, fields)
    if name == "simple_table" then
        local meta = minetest.get_meta(player_tables[player:get_player_name()].pos);

        if fields["convert"] then
            local inv = meta:get_inventory();
            local stack = inv:get_stack("input", 1);

            local value = cartographer.get_material_value(stack);

            if value.paper + value.pigment > 0 then
                meta:set_int("paper", meta:get_int("paper") + value.paper);
                meta:set_int("pigment", meta:get_int("pigment") + value.pigment);
                inv:set_stack("input", 1, ItemStack(nil));
            end 
        elseif fields["craft"] then
            local size = meta:get_int("size");
            local detail = meta:get_int("detail");
            local scale = meta:get_int("scale");
            local cost, is_positive = get_craft_material_cost(meta);

            if is_positive and can_afford(cost, meta) then
                meta:set_int("paper",  meta:get_int("paper") - cost.paper);
                meta:set_int("pigment", meta:get_int("pigment") - cost.pigment);

                local inv = meta:get_inventory();
                local stack = inv:get_stack("output", 1);

                if stack:is_empty() then
                    inv:set_stack("output", 1, cartographer.create_map_item(size, 1 + detail, scale));
                else
                    local smeta = stack:get_meta();
                    smeta:set_int("cartographer:detail", 1 + detail);
                    cartographer.resize_map_item(smeta, size);

                    local map = cartographer.get_map(smeta:get_int("cartographer:map_id"));
                    if map then
                        map.detail = 1 + detail;
                    end
                    inv:set_stack("output", 1, stack);
                end

                cartographer.map_sound("cartographer_write", player);
            end
        elseif fields["copy"] then
            local cost = get_copy_material_cost(meta);
            if can_afford(cost, meta) then
                meta:set_int("paper",  meta:get_int("paper") - cost.paper);
                meta:set_int("pigment", meta:get_int("pigment") - cost.pigment);

                cartographer.map_sound("cartographer_write", player);

                local inv = meta:get_inventory();
                inv:set_stack("copy_output", 1, cartographer.copy_map_item(inv:get_stack("copy_input", 1)));
            end
        elseif fields["s"] then
            meta:set_int("size", SIZE_SMALL);
        elseif fields["l"] then
            meta:set_int("size", SIZE_LARGE);
        elseif fields["1"] then
            meta:set_int("detail", 0);
        elseif fields["2"] then
            meta:set_int("detail", 1);
        elseif fields["3"] then
            meta:set_int("detail", 2);
        elseif fields["4"] then
            meta:set_int("detail", 3);
        elseif fields["1x"] then
            meta:set_int("scale", SCALE_SMALL);
        elseif fields["4x"] then
            meta:set_int("scale", SCALE_LARGE);
        elseif fields["tab1"] then
            player_tables[player:get_player_name()].tab = 1;
            cartographer.map_sound("cartographer_turn_page", player);
        elseif fields["tab2"] then
            player_tables[player:get_player_name()].tab = 2;
            cartographer.map_sound("cartographer_turn_page", player);
        elseif fields["tab3"] then
            player_tables[player:get_player_name()].tab = 3;
            cartographer.map_sound("cartographer_turn_page", player);
        end

        if not fields["quit"] then
            table_formspec(player:get_player_name());
        end
    end
end);

-- Called after a table is placed. Sets up the table's inventory and metadata.
-- pos: The node's position
local function setup_table_node(pos)
    local meta = minetest.get_meta(pos);
    meta:get_inventory():set_size("input", 1);
    meta:get_inventory():set_size("output", 1);
    meta:get_inventory():set_size("copy_input", 1);
    meta:get_inventory():set_size("copy_output", 1);

    meta:set_int("size", SIZE_SMALL);
    meta:set_int("scale", SCALE_SMALL);
    meta:set_int("detail", 0);
end

-- Called when the player tries to put an item into one of the table's
-- inventories.
-- listname: The name of the inventory the item is being placed in.
-- stack: The itemstack
--
-- Returns 0 if the place is invalid; otherwise, returns the number of items
-- that can be placed.
local function table_can_put(_, listname, _, stack, _)
    if listname == "copy_output" then
        return 0;
    end

    if stack:get_name() ~= "cartographer:map" and (listname == "output" or listname == "copy_input") then
        return 0;
    end

    return stack:get_count();
end

-- Called when the player tries to move an item between two of the table's
-- inventories.
-- to_list: The name of the inventory the item is being placed in.
-- count: The number of items being moved
--
-- Returns 0 if the move is invalid; otherwise, returns the number of items
-- that can be moved.
local function table_can_move(_, _, _, to_list, _, count, _)
    if to_list == "copy_output" then
        return 0;
    end

    return count;
end

-- Called when a change occurs in a table's inventory
-- pos: The node's position
-- listname: The name of the changed inventory list
local function table_on_items_changed(pos, listname, _, _, _)
    for player, data in pairs(player_tables) do
        if vector.equals(pos, data.pos) and (
                        (data.tab == 1 and listname == "input")
                     or (data.tab == 2 and listname == "output")
                     or (data.tab == 3 and listname == "copy_input")) then
            table_formspec(player);
        end
    end
end

minetest.register_node("cartographer:simple_table", {
    description = "Shabby Cartographer's Table",
    drawtype = "mesh",
    mesh = cartographer.skin.table_skins.simple_table.node_mesh,
    tiles = { cartographer.skin.table_skins.simple_table.node_texture },
    paramtype2 = "facedir",
    groups = {
        choppy = 2,
        oddly_breakable_by_hand = 2,
    },
    selection_box = {
        type = "fixed",
        fixed = {
            {-0.5, -0.5, -0.375, 0.5, 0.6875, 0.375},
        },
    },
    collision_box = {
        type = "fixed",
        fixed = {
            {-0.5, -0.5, -0.375, 0.5, 0.6875, 0.375},
        },
    },
    on_rightclick = function(pos, node, player, itemstack, pointed_thing)
        player_tables[player:get_player_name()] = {
            pos = minetest.get_pointed_thing_position(pointed_thing),
            tab = 1,
        };

        cartographer.map_sound("cartographer_open_map", player);
        table_formspec(player:get_player_name())
    end,

    after_place_node = setup_table_node,

    allow_metadata_inventory_move = table_can_move,
    allow_metadata_inventory_put = table_can_put,
    on_metadata_inventory_put = table_on_items_changed,
    on_metadata_inventory_take = table_on_items_changed,
});

minetest.register_node("cartographer:standard_table", {
    description = "Simple Cartographer's Table",
    drawtype = "mesh",
    mesh = cartographer.skin.table_skins.standard_table.node_mesh,
    tiles = { cartographer.skin.table_skins.standard_table.node_texture },
    paramtype2 = "facedir",
    groups = {
        choppy = 2,
        oddly_breakable_by_hand = 2,
    },
    selection_box = {
        type = "fixed",
        fixed = {
            {-0.5, -0.5, -0.375, 0.5, 0.6875, 0.375},
        },
    },
    collision_box = {
        type = "fixed",
        fixed = {
            {-0.5, -0.5, -0.375, 0.5, 0.6875, 0.375},
        },
    },
    on_rightclick = function(pos, node, player, itemstack, pointed_thing)
        player_tables[player:get_player_name()] = {
            pos = minetest.get_pointed_thing_position(pointed_thing),
            tab = 1,
        };

        cartographer.map_sound("cartographer_open_map", player);
        table_formspec(player:get_player_name())
    end,

    after_place_node = setup_table_node,

    allow_metadata_inventory_move = table_can_move,
    allow_metadata_inventory_put = table_can_put,
    on_metadata_inventory_put = table_on_items_changed,
    on_metadata_inventory_take = table_on_items_changed,
});

minetest.register_node("cartographer:advanced_table", {
    description = "Advanced Cartographer's Table",
    drawtype = "mesh",
    mesh = cartographer.skin.table_skins.advanced_table.node_mesh,
    tiles = { cartographer.skin.table_skins.advanced_table.node_texture },
    paramtype2 = "facedir",
    groups = {
        choppy = 2,
        oddly_breakable_by_hand = 2,
    },
    selection_box = {
        type = "fixed",
        fixed = {
            {-0.5, -0.5, -0.375, 0.5, 0.6875, 0.375},
        },
    },
    collision_box = {
        type = "fixed",
        fixed = {
            {-0.5, -0.5, -0.375, 0.5, 0.6875, 0.375},
        },
    },
    on_rightclick = function(pos, node, player, itemstack, pointed_thing)
        player_tables[player:get_player_name()] = {
            pos = minetest.get_pointed_thing_position(pointed_thing),
            tab = 1,
        };

        cartographer.map_sound("cartographer_open_map", player);
        table_formspec(player:get_player_name())
    end,

    after_place_node = setup_table_node,

    allow_metadata_inventory_move = table_can_move,
    allow_metadata_inventory_put = table_can_put,
    on_metadata_inventory_put = table_on_items_changed,
    on_metadata_inventory_take = table_on_items_changed,
});

function cartographer.register_map_material_name(name, material, value)
    if _cartographer.materials_by_name[name] == nil then
        _cartographer.materials_by_name[name] = {
            [material] = value or 1,
        };
    else
        _cartographer.materials_by_name[name][material] = value;
    end
end

function cartographer.register_map_material_group(name, material, value)
    if _cartographer.materials_by_group[name] == nil then
        _cartographer.materials_by_group[name] = {
            [material] = value or 1,
        };
    else
        _cartographer.materials_by_group[name][material] = value;
    end
end