Add filter-by-category functionality (#171)

- Added API for configuring categories
- Added display for categories above page
- Reduced height of page by 1 row to make room for categories
- Added L/R scroll through when there are more categories than columns
- Added pre-filter methods for categories and uncategorised items
- Added categories for (most) items in the default game


Co-authored-by: Oversword <bionc:oversword.co.uk>

.luacheckrc

@@ -14,6 +14,7 @@ read_globals = {
 	"ItemStack", "datastorage",
 
 	"hb",
+	"doors",
 }
 
 files["callbacks.lua"].ignore = { "player", "draw_lite_mode" }

callbacks.lua

@@ -19,6 +19,8 @@ minetest.register_on_joinplayer(function(player)
 	unified_inventory.active_search_direction[player_name] = "nochange"
 	unified_inventory.apply_filter(player, "", "nochange")
 	unified_inventory.current_searchbox[player_name] = ""
+	unified_inventory.current_category[player_name] = "all"
+	unified_inventory.current_category_scroll[player_name] = 0
 	unified_inventory.alternate[player_name] = 1
 	unified_inventory.current_item[player_name] = nil
 	unified_inventory.current_craft_direction[player_name] = "recipe"
@@ -69,6 +71,41 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 		unified_inventory.current_searchbox[player_name] = fields.searchbox
 	end
 
+
+	local clicked_category
+	for name, value in pairs(fields) do
+		local category_name = string.match(name, "^category_(.+)$")
+		if category_name then
+			clicked_category = category_name
+			break
+		end
+	end
+
+	if clicked_category
+	and clicked_category ~= unified_inventory.current_category[player_name] then
+		unified_inventory.current_category[player_name] = clicked_category
+		unified_inventory.apply_filter(player, unified_inventory.current_searchbox[player_name], "nochange")
+		unified_inventory.set_inventory_formspec(player,
+				unified_inventory.current_page[player_name])
+	end
+
+	if fields.next_category then
+		local scroll = math.min(#unified_inventory.category_list-ui_peruser.pagecols, unified_inventory.current_category_scroll[player_name] + 1)
+		if scroll ~= unified_inventory.current_category_scroll[player_name] then
+			unified_inventory.current_category_scroll[player_name] = scroll
+			unified_inventory.set_inventory_formspec(player,
+					unified_inventory.current_page[player_name])
+		end
+	end
+	if fields.prev_category then
+		local scroll = math.max(0, unified_inventory.current_category_scroll[player_name] - 1)
+		if scroll ~= unified_inventory.current_category_scroll[player_name] then
+			unified_inventory.current_category_scroll[player_name] = scroll
+			unified_inventory.set_inventory_formspec(player,
+					unified_inventory.current_page[player_name])
+		end
+	end
+
 	for i, def in pairs(unified_inventory.buttons) do
 		if fields[def.name] then
 			def.action(player)
@@ -126,6 +163,7 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 			clicked_item = unified_inventory.demangle_for_formspec(mangled_item)
 			if string.sub(clicked_item, 1, 6) == "group:" then
 				-- Change search filter to this group
+				unified_inventory.current_category[player_name] = "all"
 				apply_new_filter(player, clicked_item, new_dir)
 				return
 			end

category.lua

@@ -0,0 +1,149 @@
+local S = minetest.get_translator("unified_inventory")
+
+unified_inventory.registered_categories = {}
+unified_inventory.registered_category_items = {}
+unified_inventory.category_list = {}
+
+local function char_to_sort_index(char_code)
+	if char_code <= 32 then
+		-- Command codes, no thanks
+		return 0
+	end
+	if char_code <= 64 then
+		-- Sorts numbers, and some punctuation, after letters
+		return char_code
+	end
+	if char_code >= 158 then
+		-- Out of sortable range
+		return 0
+	end
+	if char_code > 122 then
+		-- Avoids overlap with {, |, } and ~
+		return char_code - 58
+	end
+	if char_code > 96 then
+		-- Normalises lowercase with uppercase
+		return char_code - 96
+	end
+	return char_code - 64
+end
+
+local function string_to_sort_index(str)
+	local max_chars = 5
+	local power = 100
+	local index = 0
+	for i=1,math.min(#str, max_chars) do
+		index = index + (char_to_sort_index(string.byte(str, i))/(power^i))
+	end
+	return index
+end
+
+function update_category_list()
+	local category_list = {}
+	table.insert(category_list, {
+		name = "all",
+		label = S("All Items"),
+		symbol = "ui_category_all.png",
+		index = -2,
+	})
+	table.insert(category_list, {
+		name = "uncategorized",
+		label = S("Misc. Items"),
+		symbol = "ui_category_none.png",
+		index = -1,
+	})
+	for category, def in pairs(unified_inventory.registered_categories) do
+		table.insert(category_list, {
+			name = category,
+			label = def.label or category,
+			symbol = def.symbol,
+			index = def.index or                    -- sortby defined order
+					string_to_sort_index(category)  -- or do a rudimentary alphabetical sort
+		})
+	end
+	table.sort(category_list, function (a,b)
+		return a.index < b.index
+	end)
+	unified_inventory.category_list = category_list
+end
+
+local function ensure_category_exists(category_name)
+	if not unified_inventory.registered_categories[category_name] then
+		unified_inventory.registered_categories[category_name] = {
+			symbol = "default:stick",
+			label = category_name
+		}
+	end
+	if not unified_inventory.registered_category_items[category_name] then
+		unified_inventory.registered_category_items[category_name] = {}
+	end
+end
+
+function unified_inventory.register_category(category_name, config)
+	ensure_category_exists(category_name)
+	if config and config.symbol then
+		unified_inventory.set_category_symbol(category_name, config.symbol)
+	end
+	if config and config.label then
+		unified_inventory.set_category_label(category_name, config.label)
+	end
+	if config and config.index then
+		unified_inventory.set_category_index(category_name, config.index)
+	end
+	if config and config.items then
+		unified_inventory.add_category_items(category_name, config.items)
+	end
+	update_category_list()
+end
+function unified_inventory.set_category_symbol(category_name, symbol)
+	ensure_category_exists(category_name)
+	unified_inventory.registered_categories[category_name].symbol = symbol
+	update_category_list()
+end
+function unified_inventory.set_category_label(category_name, label)
+	ensure_category_exists(category_name)
+	unified_inventory.registered_categories[category_name].label = label
+	update_category_list()
+end
+function unified_inventory.set_category_index(category_name, index)
+	ensure_category_exists(category_name)
+	unified_inventory.registered_categories[category_name].index = index
+	update_category_list()
+end
+function unified_inventory.add_category_item(category_name, item)
+	ensure_category_exists(category_name)
+	unified_inventory.registered_category_items[category_name][item] = true
+end
+function unified_inventory.add_category_items(category_name, items)
+	for _,item in ipairs(items) do
+		unified_inventory.add_category_item(category_name, item)
+	end
+end
+
+function unified_inventory.remove_category_item(category_name, item)
+	unified_inventory.registered_category_items[category_name][item] = nil
+end
+function unified_inventory.remove_category(category_name)
+	unified_inventory.registered_categories[category_name] = nil
+	unified_inventory.registered_category_items[category_name] = nil
+	update_category_list()
+end
+
+function unified_inventory.find_category(item)
+	-- Returns the first category the item exists in
+	-- Best for checking if an item has any category at all
+	for category, items in pairs(unified_inventory.registered_category_items) do
+		if items[item] then return category end
+	end
+end
+function unified_inventory.find_categories(item)
+	-- Returns all the categories the item exists in
+	-- Best for listing all categories
+	local categories = {}
+	for category, items in pairs(unified_inventory.registered_category_items) do
+		if items[item] then
+			table.insert(categories, category)
+		end
+	end
+	return categories
+end