From 6aecae6eea436849b9a80dbfa99bb0aa42c31d84 Mon Sep 17 00:00:00 2001
From: Elias Fleckenstein <eliasfleckenstein@web.de>
Date: Sun, 25 Apr 2021 13:50:07 +0200
Subject: [PATCH] Simplify damage pipeline; Add on_death and on_damage
 callbacks

---
 mods/CORE/mcl_damage/init.lua | 48 ++++++++++++++++++++++++++++++++---
 mods/CORE/mcl_util/init.lua   | 21 ++++-----------
 2 files changed, 50 insertions(+), 19 deletions(-)

diff --git a/mods/CORE/mcl_damage/init.lua b/mods/CORE/mcl_damage/init.lua
index bc5280841c..24c5fb42cb 100644
--- a/mods/CORE/mcl_damage/init.lua
+++ b/mods/CORE/mcl_damage/init.lua
@@ -1,5 +1,7 @@
 mcl_damage = {
 	modifiers = {},
+	damage_callbacks = {},
+	death_callbacks = {},
 	types = {
 		in_fire = {is_fire = true},
 		lightning_bolt = {is_lightning = true},
@@ -35,9 +37,17 @@ function mcl_damage.register_modifier(func, priority)
 	table.insert(mcl_damage.modifiers, {func = func, priority = priority or 0})
 end
 
-function mcl_damage.do_modifiers(player, damage, reason)
+function mcl_damage.register_on_damage(func)
+	table.insert(mcl_damage.damage_callbacks, func)
+end
+
+function mcl_damage.register_on_death(func)
+	table.insert(mcl_damage.death_callbacks, func)
+end
+
+function mcl_damage.run_modifiers(obj, damage, reason)
 	for _, modf in ipairs(mcl_damage.modifiers) do
-		damage = modf.func(player, damage, reason) or damage
+		damage = modf.func(obj, damage, reason) or damage
 		if damage == 0 then
 			return 0
 		end
@@ -46,6 +56,20 @@ function mcl_damage.do_modifiers(player, damage, reason)
 	return damage
 end
 
+local function run_callbacks(funcs, ...)
+	for _, func in pairs(funcs) do
+		func(...)
+	end
+end
+
+function mcl_damage.run_damage_callbacks(obj, damage, reason)
+	run_callbacks(mcl_damage.damage_callbacks, obj, damage, reason)
+end
+
+function mcl_damage.run_death_callbacks(obj, reason)
+	run_callbacks(mcl_damage.death_callbacks, obj, reason)
+end
+
 function mcl_damage.from_punch(mcl_reason, object)
 	mcl_reason.direct = object
 	local luaentity = mcl_reason.direct:get_luaentity()
@@ -69,6 +93,10 @@ function mcl_damage.finish_reason(mcl_reason)
 end
 
 function mcl_damage.from_mt(mt_reason)
+	if mt_reason._mcl_reason then
+		return mt_reason._mcl_reason
+	end
+
 	local mcl_reason = {type = "generic"}
 
 	if mt_reason._mcl_type then
@@ -95,6 +123,7 @@ function mcl_damage.from_mt(mt_reason)
 	end
 
 	mcl_damage.finish_reason(mcl_reason)
+	mt_reason._mcl_reason = mcl_reason
 
 	return mcl_reason
 end
@@ -105,11 +134,24 @@ end
 
 minetest.register_on_player_hpchange(function(player, hp_change, mt_reason)
 	if hp_change < 0 then
-		hp_change = -mcl_damage.do_modifiers(player, -hp_change, mcl_damage.from_mt(mt_reason))
+		if player:get_hp() <= 0 then
+			return 0
+		end
+		hp_change = -mcl_damage.run_modifiers(player, -hp_change, mcl_damage.from_mt(mt_reason))
 	end
 	return hp_change
 end, true)
 
+minetest.register_on_player_hpchange(function(player, hp_change, mt_reason)
+	if hp_change < 0 then
+		mcl_damage.run_damage_callbacks(player, -hp_change, mcl_damage.from_mt(mt_reason))
+	end
+end, false)
+
+minetest.register_on_dieplayer(function(player, mt_reason)
+	mcl_damage.run_death_callbacks(player, mcl_damage.from_mt(mt_reason))
+end)
+
 minetest.register_on_mods_loaded(function()
 	table.sort(mcl_damage.modifiers, function(a, b) return a.priority < b.priority end)
 end)
diff --git a/mods/CORE/mcl_util/init.lua b/mods/CORE/mcl_util/init.lua
index 741dc604e7..a2a1ea816c 100644
--- a/mods/CORE/mcl_util/init.lua
+++ b/mods/CORE/mcl_util/init.lua
@@ -475,32 +475,21 @@ function mcl_util.use_item_durability(itemstack, n)
 end
 
 function mcl_util.deal_damage(target, damage, mcl_reason)
-	mcl_reason = mcl_reason or {}
-
 	local luaentity = target:get_luaentity()
 
 	if luaentity then
 		if luaentity.deal_damage then
-			luaentity:deal_damage(damage, mcl_reason)
+			luaentity:deal_damage(damage, mcl_reason or {type = "generic"})
 			return
 		elseif luaentity._cmi_is_mob then
-			local puncher = mcl_reason.direct or target
-			target:punch(puncher, 1.0, {full_punch_interval = 1.0, damage_groups = {fleshy = damage}}, vector.direction(puncher:get_pos(), target:get_pos()), damage)
+			-- local puncher = mcl_reason and mcl_reason.direct or target
+			-- target:punch(puncher, 1.0, {full_punch_interval = 1.0, damage_groups = {fleshy = damage}}, vector.direction(puncher:get_pos(), target:get_pos()), damage)
+			luaentity.health = luaentity.health - damage
 			return
 		end
 	end
 
-	local mt_reason
-
-	if target:is_player() then
-		mt_reason = {}
-
-		for key, value in pairs(mcl_reason) do
-			mt_reason["_mcl_" .. key] = value
-		end
-	end
-
-	target:set_hp(target:get_hp() - damage, mt_reason)
+	target:set_hp(target:get_hp() - damage, {_mcl_reason = mcl_reason})
 end
 
 function mcl_util.get_hp(obj)