Add an item pick up callback (2) (#7712)

Co-authored-by: SmallJoker <mk939@ymail.com>
Co-authored-by: Jude Melton-Houghton <jwmhjwmh@gmail.com>

3 files changed, 48 insertions, 12 deletions

diff --git a/builtin/game/item.lua b/builtin/game/item.lua
index af3fcb645..2e8fcc343 100644
--- a/builtin/game/item.lua
+++ b/builtin/game/item.lua
@@ -349,8 +349,26 @@ function core.item_drop(itemstack, dropper, pos)
 	-- environment failed
 end
 
+function core.item_pickup(itemstack, picker, pointed_thing, ...)
+	itemstack = ItemStack(itemstack)
+	-- Invoke global on_item_pickup callbacks.
+	for _, callback in ipairs(core.registered_on_item_pickups) do
+		local result = callback(itemstack, picker, pointed_thing, ...)
+		if result then
+			return ItemStack(result)
+		end
+	end
+
+	-- Pickup item.
+	local inv = picker and picker:get_inventory()
+	if inv then
+		return inv:add_item("main", itemstack)
+	end
+	return itemstack
+end
+
 function core.do_item_eat(hp_change, replace_with_item, itemstack, user, pointed_thing)
-	for _, callback in pairs(core.registered_on_item_eats) do
+	for _, callback in ipairs(core.registered_on_item_eats) do
 		local result = callback(hp_change, replace_with_item, itemstack, user, pointed_thing)
 		if result then
 			return result
@@ -589,6 +607,7 @@ core.nodedef_default = {
 	-- Interaction callbacks
 	on_place = redef_wrapper(core, 'item_place'), -- core.item_place
 	on_drop = redef_wrapper(core, 'item_drop'), -- core.item_drop
+	on_pickup = redef_wrapper(core, 'item_pickup'), -- core.item_pickup
 	on_use = nil,
 	can_dig = nil,
 
@@ -641,6 +660,7 @@ core.craftitemdef_default = {
 	-- Interaction callbacks
 	on_place = redef_wrapper(core, 'item_place'), -- core.item_place
 	on_drop = redef_wrapper(core, 'item_drop'), -- core.item_drop
+	on_pickup = redef_wrapper(core, 'item_pickup'), -- core.item_pickup
 	on_secondary_use = redef_wrapper(core, 'item_secondary_use'),
 	on_use = nil,
 }
@@ -661,6 +681,7 @@ core.tooldef_default = {
 	on_place = redef_wrapper(core, 'item_place'), -- core.item_place
 	on_secondary_use = redef_wrapper(core, 'item_secondary_use'),
 	on_drop = redef_wrapper(core, 'item_drop'), -- core.item_drop
+	on_pickup = redef_wrapper(core, 'item_pickup'), -- core.item_pickup
 	on_use = nil,
 }
 
@@ -677,8 +698,9 @@ core.noneitemdef_default = {  -- This is used for the hand and unknown items
 	tool_capabilities = nil,
 
 	-- Interaction callbacks
-	on_place = redef_wrapper(core, 'item_place'),
+	on_place = redef_wrapper(core, 'item_place'), -- core.item_place
 	on_secondary_use = redef_wrapper(core, 'item_secondary_use'),
+	on_pickup = redef_wrapper(core, 'item_pickup'), -- core.item_pickup
 	on_drop = nil,
 	on_use = nil,
 }
diff --git a/builtin/game/item_entity.lua b/builtin/game/item_entity.lua
index 53f98a7c7..f321bb1dd 100644
--- a/builtin/game/item_entity.lua
+++ b/builtin/game/item_entity.lua
@@ -318,16 +318,29 @@ core.register_entity(":__builtin:item", {
 		end
 	end,
 
-	on_punch = function(self, hitter)
-		local inv = hitter:get_inventory()
-		if inv and self.itemstring ~= "" then
-			local left = inv:add_item("main", self.itemstring)
-			if left and not left:is_empty() then
-				self:set_item(left)
-				return
-			end
+	on_punch = function(self, hitter, ...)
+		if self.itemstring == "" then
+			self.object:remove()
+			return
+		end
+
+		-- Call on_pickup callback in item definition.
+		local itemstack = ItemStack(self.itemstring)
+		local callback = itemstack:get_definition().on_pickup
+
+		local ret = callback(itemstack, hitter, {type = "object", ref = self.object}, ...)
+		if not ret then
+			-- Don't modify (and don't reset rotation)
+			return
+		end
+		itemstack = ItemStack(ret)
+
+		-- Handle the leftover itemstack
+		if itemstack:is_empty() then
+			self.itemstring = ""
+			self.object:remove()
+		else
+			self:set_item(itemstack)
 		end
-		self.itemstring = ""
-		self.object:remove()
 	end,
 })
diff --git a/builtin/game/register.lua b/builtin/game/register.lua
index 8b6f5b990..d4c876898 100644
--- a/builtin/game/register.lua
+++ b/builtin/game/register.lua
@@ -607,6 +607,7 @@ core.registered_on_crafts, core.register_on_craft = make_registration()
 core.registered_craft_predicts, core.register_craft_predict = make_registration()
 core.registered_on_protection_violation, core.register_on_protection_violation = make_registration()
 core.registered_on_item_eats, core.register_on_item_eat = make_registration()
+core.registered_on_item_pickups, core.register_on_item_pickup = make_registration()
 core.registered_on_punchplayers, core.register_on_punchplayer = make_registration()
 core.registered_on_priv_grant, core.register_on_priv_grant = make_registration()
 core.registered_on_priv_revoke, core.register_on_priv_revoke = make_registration()