Add optional Progressive Mode

The progressive mode is a Terraria-like crafting guide system that only
list the items in the crafting guide for which you already have the ingredients
in your inventory. The progressive mode is disabled by default and can be enabled with
`craftguide_progressive_mode = true` in `minetest.conf`.

Thanks to @kaeza and @Wuzzy2 for the idea.
See discussion on https://github.com/minetest/minetest_game/issues/1435

README.md

@@ -1,8 +1,14 @@
 ## Crafting Guide ##
 
-##### A simple and fast Crafting Guide that doesn't suck for Minetest.
+#### A simple and fast Crafting Guide that doesn't suck for Minetest. ####
 
-##### Usable with a book named *"Crafting Guide"*. #####
+#### Usable with a book named *"Crafting Guide"*. ####
+
+#### This crafting guide features two modes : Normal and Progressive. ####
+The Progressive mode is a Terraria-like crafting guide system that only 
+list the items in the crafting guide for which you already have the ingredients
+in your inventory. The progressive mode is disabled by default and can be enabled with 
+`craftguide_progressive_mode = true` in `minetest.conf`.
 
 ![Preview](http://i.imgur.com/xblp1Vs.png)
 

init.lua

@@ -1,5 +1,6 @@
 local craftguide, datas, npp = {}, {}, 8*3
-local min, ceil = math.min, math.ceil
+local min, ceil, max = math.min, math.ceil, math.max
+local progressive_mode = minetest.setting_getbool("craftguide_progressive_mode")
 
 local group_stereotypes = {
 	wool	     = "wool:white",
@@ -11,7 +12,7 @@ local group_stereotypes = {
 	mesecon_conductor_craftable = "mesecons:wire_00000000_off",
 }
 
-function craftguide:get_recipe(item)
+function craftguide:group_to_item(item)
 	if item:sub(1,6) == "group:" then
 		local short_itemstr = item:sub(7)
 		if group_stereotypes[short_itemstr] then
@@ -52,8 +53,8 @@ end
 
 function craftguide:get_formspec(player_name)
 	local data = datas[player_name]
-	data.pagenum = data.pagenum or 1
-	data.recipe_num = data.recipe_num or 1
+	data.pagenum = max(1, data.pagenum or 1)
+	data.pagemax = max(1, data.pagemax or 1)
 
 	local formspec = [[ size[8,6.6;]
 			button[2.5,0.2;0.8,0.5;search;?]
@@ -69,6 +70,10 @@ function craftguide:get_formspec(player_name)
 				minetest.formspec_escape(data.filter).."]"..
 			default.gui_bg..default.gui_bg_img
 
+	if not next(data.items) then
+		formspec = formspec.."label[2.9,2;No item to show]"
+	end
+
 	local first_item = (data.pagenum - 1) * npp
 	for i = first_item, first_item + npp - 1 do
 		local name = data.items[i+1]
@@ -81,8 +86,16 @@ function craftguide:get_formspec(player_name)
 
 	if data.item and minetest.registered_items[data.item] then
 		local recipes = minetest.get_all_craft_recipes(data.item)
-		if data.recipe_num > #recipes then data.recipe_num = 1 end
+		data.recipe_num = data.recipe_num or 1
 
+		if progressive_mode then
+			local T = self:recipe_in_inv(player_name, data.item)
+			for i=#T, 1, -1 do
+				if not T[i] then table.remove(recipes, i) end
+			end
+		end
+
+		if data.recipe_num > #recipes then data.recipe_num = 1 end
 		if #recipes > 1 then formspec = formspec..
 			[[ button[0,6;2,1;alternate;Alternate]
 			label[0,5.5;Recipe ]]..data.recipe_num.." of "..#recipes.."]"
@@ -105,7 +118,7 @@ function craftguide:get_formspec(player_name)
 			local Y = ceil(i / width + (5 - min(2, rows)))
 			local groups = self:extract_groups(v)
 			local label = (groups and "\nG") or ""
-			local item = self:get_recipe(v)
+			local item = self:group_to_item(v)
 			local tooltip = self:get_tooltip(item, recipe_type, width, groups)
 
 			formspec = formspec.."item_image_button["..X..","..Y..";1,1;"..
@@ -121,6 +134,29 @@ function craftguide:get_formspec(player_name)
 	minetest.show_formspec(player_name, "craftguide:book", formspec)
 end
 
+local function has_item(T)
+	for i=1, #T do
+		if T[i] then return true end
+	end
+end
+
+function craftguide:recipe_in_inv(player_name, item_name)
+	local player = minetest.get_player_by_name(player_name)
+	local inv = player:get_inventory()
+	local recipes = minetest.get_all_craft_recipes(item_name) or {}
+	local T = {}
+
+	for i=1, #recipes do
+		T[i] = true
+		for _, item in pairs(recipes[i].items) do
+			if not inv:contains_item("main", self:group_to_item(item)) then
+				T[i] = false
+			end
+		end
+	end
+	return T, has_item(T)
+end
+
 function craftguide:get_items(player_name)
 	local items_list, data = {}, datas[player_name]
 	for name, def in pairs(minetest.registered_items) do
@@ -129,9 +165,15 @@ function craftguide:get_items(player_name)
 			    def.description and def.description ~= "" and
 			   (def.name:find(data.filter, 1, true) or
 				def.description:lower():find(data.filter, 1, true)) then
+
+			if progressive_mode then
+				local _, has_item = self:recipe_in_inv(player_name, name)
+				if has_item then items_list[#items_list+1] = name end
+			else
 				items_list[#items_list+1] = name
 			end
 		end
+	end
 
 	table.sort(items_list)
 	data.items = items_list
@@ -165,6 +207,10 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 		craftguide:get_formspec(player_name)
 	else for item in pairs(fields) do
 		 if minetest.get_craft_recipe(item).items then
+			if progressive_mode then
+				local _, has_item = craftguide:recipe_in_inv(player_name, item)
+				if not has_item then return end
+			end
 			data.item = item
 			data.recipe_num = 1
 			craftguide:get_formspec(player_name)
@@ -181,7 +227,7 @@ minetest.register_craftitem("craftguide:book", {
 	groups = {book=1},
 	on_use = function(itemstack, user)
 		local player_name = user:get_player_name()
-		if not datas[player_name] then
+		if progressive_mode or not datas[player_name] then
 			datas[player_name] = {}
 			datas[player_name].filter = ""
 			craftguide:get_items(player_name)