From ca6d9a10df5110fd75d49785adf690ae270d5a31 Mon Sep 17 00:00:00 2001
From: Andrey Kozlovskiy <andrononete@gmail.com>
Date: Sat, 26 Oct 2019 18:22:33 +0300
Subject: [PATCH] Implement new crafting algorithm (#132)

* Implement new crafting algorithm

* Take craft width into account when creating craft index
* Fix moving logic, correctly check for empty stacks
* Return early when there's not enough items for craft
* Bound match_count with smallest stack_max value, take from inventory only if needed
* Continue if item can't be moved to the current position.
* Fix metadata loss and. Improve placement for some corner cases.
* Drop items from oversized stacks on the ground
* Place items exactly as displayed in the guide
* One source list one destination. Try to take from destination list first
---
 api.lua         |   1 -
 init.lua        |   1 +
 match_craft.lua | 409 ++++++++++++++++++++++++++++++++++++++++++++++++
 register.lua    |  99 +-----------
 4 files changed, 413 insertions(+), 97 deletions(-)
 create mode 100644 match_craft.lua

diff --git a/api.lua b/api.lua
index 7cf8f4a..071900d 100644
--- a/api.lua
+++ b/api.lua
@@ -305,4 +305,3 @@ function unified_inventory.is_creative(playername)
 	return minetest.check_player_privs(playername, {creative=true})
 		or minetest.settings:get_bool("creative_mode")
 end
-
diff --git a/init.lua b/init.lua
index fcbcf3d..1a80abb 100644
--- a/init.lua
+++ b/init.lua
@@ -65,6 +65,7 @@ dofile(modpath.."/group.lua")
 dofile(modpath.."/api.lua")
 dofile(modpath.."/internal.lua")
 dofile(modpath.."/callbacks.lua")
+dofile(modpath.."/match_craft.lua")
 dofile(modpath.."/register.lua")
 
 if minetest.settings:get_bool("unified_inventory_bags") ~= false then
diff --git a/match_craft.lua b/match_craft.lua
new file mode 100644
index 0000000..2dd40b0
--- /dev/null
+++ b/match_craft.lua
@@ -0,0 +1,409 @@
+-- match_craft.lua
+-- Find and automatically move inventory items to the crafting grid
+-- according to the recipe.
+
+--[[
+Retrieve items from inventory lists and calculate their total count.
+Return a table of "item name" - "total count" pairs.
+
+Arguments:
+	inv: minetest inventory reference
+	lists: names of inventory lists to use
+
+Example usage:
+	-- Count items in "main" and "craft" lists of player inventory
+	unified_inventory.count_items(player_inv_ref, {"main", "craft"})
+
+Example output:
+	{
+		["default:pine_wood"] = 2,
+		["default:acacia_wood"] = 4,
+		["default:chest"] = 3,
+		["default:axe_diamond"] = 2, -- unstackable item are counted too
+		["wool:white"] = 6
+	}
+]]--
+function unified_inventory.count_items(inv, lists)
+	local counts = {}
+
+	for i = 1, #lists do
+		local name = lists[i]
+		local size = inv:get_size(name)
+		local list = inv:get_list(name)
+
+		for j = 1, size do
+			local stack = list[j]
+
+			if not stack:is_empty() then
+				local item = stack:get_name()
+				local count = stack:get_count()
+
+				counts[item] = (counts[item] or 0) + count
+			end
+		end
+	end
+
+	return counts
+end
+
+--[[
+Retrieve craft recipe items and their positions in the crafting grid.
+Return a table of "craft item name" - "set of positions" pairs.
+
+Note that if craft width is not 3 then positions are recalculated as
+if items were placed on a 3x3 grid. Also note that craft can contain
+groups of items with "group:" prefix.
+
+Arguments:
+	craft: minetest craft recipe
+
+Example output:
+	-- Bed recipe
+	{
+		["wool:white"] = {[1] = true, [2] = true, [3] = true}
+		["group:wood"] = {[4] = true, [5] = true, [6] = true}
+	}
+--]]
+function unified_inventory.count_craft_positions(craft)
+	local positions = {}
+	local craft_items = craft.items
+	local craft_type = unified_inventory.registered_craft_types[craft.type]
+	                   or unified_inventory.craft_type_defaults(craft.type, {})
+	local display_width = craft_type.dynamic_display_size
+	                      and craft_type.dynamic_display_size(craft).width
+	                      or craft_type.width
+	local craft_width = craft_type.get_shaped_craft_width
+	                    and craft_type.get_shaped_craft_width(craft)
+	                    or display_width
+	local i = 0
+
+	for y = 1, 3 do
+		for x = 1, craft_width do
+			i = i + 1
+			local item = craft_items[i]
+
+			if item ~= nil then
+				local pos = 3 * (y - 1) + x
+				local set = positions[item]
+
+				if set ~= nil then
+					set[pos] = true
+				else
+					positions[item] = {[pos] = true}
+				end
+			end
+		end
+	end
+
+	return positions
+end
+
+--[[
+For every craft item find all matching inventory items.
+- If craft item is a group then find all inventory items that matches
+  this group.
+- If craft item is not a group (regular item) then find only this item.
+
+If inventory doesn't contain needed item then found set is empty for
+this item.
+
+Return a table of "craft item name" - "set of matching inventory items"
+pairs.
+
+Arguments:
+	inv_items: table with items names as keys
+	craft_items: table with items names or groups as keys
+
+Example output:
+	{
+		["group:wood"] = {
+			["default:pine_wood"] = true,
+			["default:acacia_wood"] = true
+		},
+		["wool:white"] = {
+			["wool:white"] = true
+		}
+	}
+--]]
+function unified_inventory.find_usable_items(inv_items, craft_items)
+	local get_group = minetest.get_item_group
+	local result = {}
+
+	for craft_item in pairs(craft_items) do
+		local group = craft_item:match("^group:(.+)")
+		local found = {}
+
+		if group ~= nil then
+			for inv_item in pairs(inv_items) do
+				if get_group(inv_item, group) > 0 then
+					found[inv_item] = true
+				end
+			end
+		else
+			if inv_items[craft_item] ~= nil then
+				found[craft_item] = true
+			end
+		end
+
+		result[craft_item] = found
+	end
+
+	return result
+end
+
+--[[
+Match inventory items with craft grid positions.
+For every position select the matching inventory item with maximum
+(total_count / (times_matched + 1)) value.
+
+If for some position matching item cannot be found or match count is 0
+then return nil.
+
+Return a table of "matched item name" - "set of craft positions" pairs
+and overall match count.
+
+Arguments:
+	inv_counts: table of inventory items counts from "count_items"
+	craft_positions: table of craft positions from "count_craft_positions"
+
+Example output:
+	match_table = {
+		["wool:white"] = {[1] = true, [2] = true, [3] = true}
+		["default:acacia_wood"] = {[4] = true, [6] = true}
+		["default:pine_wood"] = {[5] = true}
+	}
+	match_count = 2
+--]]
+function unified_inventory.match_items(inv_counts, craft_positions)
+	local usable = unified_inventory.find_usable_items(inv_counts, craft_positions)
+	local match_table = {}
+	local match_count
+	local matches = {}
+
+	for craft_item, pos_set in pairs(craft_positions) do
+		local use_set = usable[craft_item]
+
+		for pos in pairs(pos_set) do
+			local pos_item
+			local pos_count
+
+			for use_item in pairs(use_set) do
+				local count = inv_counts[use_item]
+				local times_matched = matches[use_item] or 0
+				local new_pos_count = math.floor(count / (times_matched + 1))
+
+				if pos_count == nil or pos_count < new_pos_count then
+					pos_item = use_item
+					pos_count = new_pos_count
+				end
+			end
+
+			if pos_item == nil or pos_count == 0 then
+				return nil
+			end
+
+			local set = match_table[pos_item]
+
+			if set ~= nil then
+				set[pos] = true
+			else
+				match_table[pos_item] = {[pos] = true}
+			end
+
+			matches[pos_item] = (matches[pos_item] or 0) + 1
+		end
+	end
+
+	for match_item, times_matched in pairs(matches) do
+		local count = inv_counts[match_item]
+		local item_count = math.floor(count / times_matched)
+
+		if match_count == nil or item_count < match_count then
+			match_count = item_count
+		end
+	end
+
+	return match_table, match_count
+end
+
+--[[
+Remove item from inventory lists.
+Return stack of actually removed items.
+
+This function replicates the inv:remove_item function but can accept
+multiple lists.
+
+Arguments:
+	inv: minetest inventory reference
+	lists: names of inventory lists
+	stack: minetest item stack
+--]]
+function unified_inventory.remove_item(inv, lists, stack)
+	local removed = ItemStack(nil)
+	local leftover = ItemStack(stack)
+
+	for i = 1, #lists do
+		if leftover:is_empty() then
+			break
+		end
+
+		local cur_removed = inv:remove_item(lists[i], leftover)
+		removed:add_item(cur_removed)
+		leftover:take_item(cur_removed:get_count())
+	end
+
+	return removed
+end
+
+--[[
+Add item to inventory lists.
+Return leftover stack.
+
+This function replicates the inv:add_item function but can accept
+multiple lists.
+
+Arguments:
+	inv: minetest inventory reference
+	lists: names of inventory lists
+	stack: minetest item stack
+--]]
+function unified_inventory.add_item(inv, lists, stack)
+	local leftover = ItemStack(stack)
+
+	for i = 1, #lists do
+		if leftover:is_empty() then
+			break
+		end
+
+		leftover = inv:add_item(lists[i], leftover)
+	end
+
+	return leftover
+end
+
+--[[
+Move items from source list to destination list if possible.
+Skip positions specified in exclude set.
+
+Arguments:
+	inv: minetest inventory reference
+	src_list: name of source list
+	dst_list: name of destination list
+	exclude: set of positions to skip
+--]]
+function unified_inventory.swap_items(inv, src_list, dst_list, exclude)
+	local size = inv:get_size(src_list)
+	local empty = ItemStack(nil)
+
+	for i = 1, size do
+		if exclude == nil or exclude[i] == nil then
+			local stack = inv:get_stack(src_list, i)
+
+			if not stack:is_empty() then
+				inv:set_stack(src_list, i, empty)
+				local leftover = inv:add_item(dst_list, stack)
+
+				if not leftover:is_empty() then
+					inv:set_stack(src_list, i, leftover)
+				end
+			end
+		end
+	end
+end
+
+--[[
+Move matched items to the destination list.
+
+If destination list position is already occupied with some other item
+then function tries to (in that order):
+1. Move it to the source list
+2. Move it to some other unused position in destination list itself
+3. Drop it to the ground if nothing else is possible.
+
+Arguments:
+	player: minetest player object
+	src_list: name of source list
+	dst_list: name of destination list
+	match_table: table of matched items
+	amount: amount of items per every position
+--]]
+function unified_inventory.move_match(player, src_list, dst_list, match_table, amount)
+	local inv = player:get_inventory()
+	local item_drop = minetest.item_drop
+	local src_dst_list = {src_list, dst_list}
+	local dst_src_list = {dst_list, src_list}
+
+	local needed = {}
+	local moved = {}
+
+	-- Remove stacks needed for craft
+	for item, pos_set in pairs(match_table) do
+		local stack = ItemStack(item)
+		local stack_max = stack:get_stack_max()
+		local bounded_amount = math.min(stack_max, amount)
+		stack:set_count(bounded_amount)
+
+		for pos in pairs(pos_set) do
+			needed[pos] = unified_inventory.remove_item(inv, dst_src_list, stack)
+		end
+	end
+
+	-- Add already removed stacks
+	for pos, stack in pairs(needed) do
+		local occupied = inv:get_stack(dst_list, pos)
+		inv:set_stack(dst_list, pos, stack)
+
+		if not occupied:is_empty() then
+			local leftover = unified_inventory.add_item(inv, src_dst_list, occupied)
+
+			if not leftover:is_empty() then
+				inv:set_stack(dst_list, pos, leftover)
+				local oversize = unified_inventory.add_item(inv, src_dst_list, stack)
+
+				if not oversize:is_empty() then
+					item_drop(oversize, player, player:get_pos())
+				end
+			end
+		end
+
+		moved[pos] = true
+	end
+
+	-- Swap items from unused positions to src (moved positions excluded)
+	unified_inventory.swap_items(inv, dst_list, src_list, moved)
+end
+
+--[[
+Find craft match and move matched items to the destination list.
+
+If match cannot be found or match count is smaller than the desired
+amount then do nothing.
+
+If amount passed is -1 then amount is defined by match count itself.
+This is used to indicate "craft All" case.
+
+Arguments:
+	player: minetest player object
+	src_list: name of source list
+	dst_list: name of destination list
+	craft: minetest craft recipe
+	amount: desired amount of output items
+--]]
+function unified_inventory.craftguide_match_craft(player, src_list, dst_list, craft, amount)
+	local inv = player:get_inventory()
+	local src_dst_list = {src_list, dst_list}
+
+	local counts = unified_inventory.count_items(inv, src_dst_list)
+	local positions = unified_inventory.count_craft_positions(craft)
+	local match_table, match_count = unified_inventory.match_items(counts, positions)
+
+	if match_table == nil or match_count < amount then
+		return
+	end
+
+	if amount == -1 then
+		amount = match_count
+	end
+
+	unified_inventory.move_match(player, src_list, dst_list, match_table, amount)
+end
diff --git a/register.lua b/register.lua
index fe23ed2..d89c05e 100644
--- a/register.lua
+++ b/register.lua
@@ -441,65 +441,6 @@ local function craftguide_giveme(player, formname, fields)
 	player_inv:add_item("main", {name = output, count = amount})
 end
 
--- Takes any stack from "main" where the `amount` of `needed_item` may fit
--- into the given crafting stack (`craft_item`)
-local function craftguide_move_stacks(inv, craft_item, needed_item, amount)
-	if craft_item:get_count() >= amount then
-		return
-	end
-
-	local get_item_group = minetest.get_item_group
-	local group = needed_item:match("^group:(.+)")
-	if group then
-		if not craft_item:is_empty() then
-			-- Source item must be the same to fill
-			if get_item_group(craft_item:get_name(), group) ~= 0 then
-				needed_item = craft_item:get_name()
-			else
-				-- TODO: Maybe swap unmatching "craft" items
-				-- !! Would conflict with recursive function call
-				return
-			end
-		else
-			-- Take matching group from the inventory (biggest stack)
-			local main = inv:get_list("main")
-			local max_found = 0
-			for i, stack in ipairs(main) do
-				if stack:get_count() > max_found and
-						get_item_group(stack:get_name(), group) ~= 0 then
-					needed_item = stack:get_name()
-					max_found = stack:get_count()
-					if max_found >= amount then
-						break
-					end
-				end
-			end
-		end
-	else
-		if not craft_item:is_empty() and
-				craft_item:get_name() ~= needed_item then
-			return -- Item must be identical
-		end
-	end
-
-	needed_item = ItemStack(needed_item)
-	local to_take = math.min(amount, needed_item:get_stack_max())
-	to_take = to_take - craft_item:get_count()
-	if to_take <= 0 then
-		return -- Nothing to do
-	end
-	needed_item:set_count(to_take)
-
-	local taken = inv:remove_item("main", needed_item)
-	local leftover = taken:add_item(craft_item)
-	if not leftover:is_empty() then
-		-- Somehow failed to add the existing "craft" item. Undo the action.
-		inv:add_item("main", leftover)
-		return taken
-	end
-	return taken
-end
-
 local function craftguide_craft(player, formname, fields)
 	local amount
 	for k, v in pairs(fields) do
@@ -508,17 +449,14 @@ local function craftguide_craft(player, formname, fields)
 	end
 	if not amount then return end
 
-	amount = tonumber(amount) or 99 -- fallback for "all"
-	if amount <= 0 or amount > 99 then return end
+	amount = tonumber(amount) or -1 -- fallback for "all"
+	if amount == 0 or amount < -1 or amount > 99 then return end
 
 	local player_name = player:get_player_name()
 
 	local output = unified_inventory.current_item[player_name] or ""
 	if output == "" then return end
 
-	local player_inv = player:get_inventory()
-	local craft_list = player_inv:get_list("craft")
-
 	local crafts = unified_inventory.crafts_for[
 		unified_inventory.current_craft_direction[player_name]][output] or {}
 	if #crafts == 0 then return end
@@ -528,38 +466,7 @@ local function craftguide_craft(player, formname, fields)
 	local craft = crafts[alternate]
 	if craft.width > 3 then return end
 
-	local needed = craft.items
-	local width = craft.width
-	if width == 0 then
-		-- Shapeless recipe
-		width = 3
-	end
-
-	-- To spread the items evenly
-	local STEPSIZE = math.ceil(math.sqrt(amount) / 5) * 5
-	local current_count = 0
-	repeat
-		current_count = math.min(current_count + STEPSIZE, amount)
-		local index = 1
-		for y = 1, 3 do
-			for x = 1, width do
-				local needed_item = needed[index]
-				if needed_item then
-					local craft_index = ((y - 1) * 3) + x
-					local craft_item = craft_list[craft_index]
-					local newitem = craftguide_move_stacks(player_inv,
-							craft_item, needed_item, current_count)
-
-					if newitem then
-						craft_list[craft_index] = newitem
-					end
-				end
-				index = index + 1
-			end
-		end
-	until current_count == amount
-
-	player_inv:set_list("craft", craft_list)
+	unified_inventory.craftguide_match_craft(player, "main", "craft", craft, amount)
 
 	unified_inventory.set_inventory_formspec(player, "craft")
 end