Sneak attacks (#5674)

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## About The Pull Request
Bounty https://hackmd.io/@Avalon-Proto/SJGtMe5H9We

Sneak attacks require you to be directly behind someone in not in combat
while sneaking. You also need to be using a "Swift" balance or blunt
intent and have to have 10 sneak skill at the lowest.

It won't work if they are laying down, dead or unconcious and it also
works on living mobs but I doubt you can currently utilise this against
AI mobs.

They do up to ~50% more damage and up to a flat ~15% higher chance to
knockout with blunt weapons applied to the head.

~ because skill scaling is strange and you can get above 60 so it can be
higher and I think that's fine

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:cl:
add: Added stealth strikes, doing extra damage to unsuspecting targets
(Not in combat mode, need to be sneaking behind them). Sneak attacks do
up to ~50% extra damage and have up to ~15% extra chance to knockout
based on sneak.
/:cl:

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- [ ] You tested this on a local server.
- [ ] This code did not runtime during testing.
- [ ] You documented all of your changes.
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Author: CheffieGithub

code/__DEFINES/combat.dm

@@ -467,3 +467,9 @@ GLOBAL_LIST_INIT(shove_disarming_types, typecacheof(list(
 #define DODGING_PENALTY 1
 /// A define so the cooldown on the baited status and the duration of the baitcd status are the same
 #define BAIT_COOLDOWN_TIME 15 SECONDS
+
+// try_crit keys for modifiers
+/// Chance modifier
+#define CRIT_MOD_CHANCE "crit_mod"
+/// Specifically knockout modifier for head crits
+#define CRIT_MOD_KNOCKOUT_CHANCE "knockout_mod"

code/_onclick/item_attack.dm

@@ -436,42 +436,42 @@
 	var/dullfactor = 1
 	if(!I?.force)
 		return 0
+
 	// newforce starts here and is the default amount of damage the item does.
 	var/newforce = I.force
+
 	// If this weapon has no user and is somehow attacking you just return default.
 	if(!istype(user))
 		return newforce
 
 	var/dullness_ratio
 	if(I.max_blade_int && I.sharpness != IS_BLUNT)
 		dullness_ratio = I.blade_int / I.max_blade_int
-	var/cont = FALSE
+
 	var/used_str = GET_MOB_ATTRIBUTE_VALUE(user, STAT_STRENGTH)
 	if(iscarbon(user))
 		var/mob/living/carbon/C = user
-		/*
-		* If you have a dominant hand which is assigned at
-		* character creation. You suffer a -1 Str if your
-		* no using the item in your dominant hand.
-		* Check living/carbon/carbon.dm for more info.
-		*/
 		if(C.domhand)
 			used_str = C.get_str_arms(C.used_hand)
-	//STR is +1 from STRONG stance and -1 from SWIFT stance
+
+	// Apply rmb intent modifiers
 	if(istype(user.rmb_intent, /datum/rmb_intent/strong))
 		used_str++
-	if(istype(user.rmb_intent, /datum/rmb_intent/swift))
+	else if(istype(user.rmb_intent, /datum/rmb_intent/swift))
 		used_str--
-	if(istype(user.rmb_intent, /datum/rmb_intent/weak))
+	else if(istype(user.rmb_intent, /datum/rmb_intent/weak))
 		used_str /= 2
+
 	//Your max STR is 20.
-	used_str = CLAMP(used_str, 1, 20)
+	used_str = clamp(used_str, 1, 20)
+
 	//Vampire checks for Potence
 	if(ishuman(user))
 		var/mob/living/carbon/human/user_human = user
 		if(user_human.clan)
 			used_str += floor(0.5 * user_human.potence_weapon_buff)
 			// For each level of potence user gains 0.5 STR, at 5 Potence their STR buff is 2.5
+
 	if(used_str >= 11)
 		newforce = newforce + (newforce * ((used_str - 10) * 0.1))
 		if(dullness_ratio && (user.used_intent.blade_class in list(BCLASS_CHOP, BCLASS_CUT, BCLASS_STAB)))
@@ -488,8 +488,8 @@
 		if(HAS_TRAIT(I, TRAIT_WIELDED))
 			effective *= 0.75
 		//Strength influence is reduced to 30%
-		if(effective > GET_MOB_ATTRIBUTE_VALUE(user, STAT_STRENGTH))
-			newforce = max(newforce*0.3, 1)
+		if(effective > used_str)
+			newforce = max(newforce * 0.3, 1)
 
 	//Blade Dulling Starts here.
 	switch(blade_dulling)
@@ -503,7 +503,6 @@
 					else
 						dullfactor = 0.45 + (lumberskill * 0.15)
 						lumberjacker.mind.add_sleep_experience(/datum/attribute/skill/labor/lumberjacking, (GET_MOB_ATTRIBUTE_VALUE(lumberjacker, STAT_INTELLIGENCE)*0.2))
-					cont = TRUE
 				if(BCLASS_CHOP)
 					//Additional damage for axes against trees.
 					if(istype(I, /obj/item/weapon))
@@ -515,51 +514,42 @@
 						dullfactor = 0.2
 					else
 						dullfactor = 1.5
-					cont = TRUE
-			if(!cont)
-				return 0
+				else
+					return 0
 		if(DULLING_BASH) //stone/metal, can't be attacked by cutting
 			switch(user.used_intent.blade_class)
 				if(BCLASS_BLUNT)
-					cont = TRUE
+					EMPTY_BLOCK_GUARD
 				if(BCLASS_SMASH)
 					dullfactor = 1.5
-					cont = TRUE
 				if(BCLASS_DRILL)
 					dullfactor = 10
-					cont = TRUE
 				if(BCLASS_PICK)
 					dullfactor = 1.5
-					cont = TRUE
-			if(!cont)
-				return 0
+				else
+					return 0
 		if(DULLING_BASHCHOP) //structures that can be attacked by clubs also (doors fences etc)
 			switch(user.used_intent.blade_class)
 				if(BCLASS_CUT)
 					if(!I.remove_bintegrity(1, user))
 						dullfactor = 0.8
-					cont = TRUE
 				if(BCLASS_CHOP)
 					if(!I.remove_bintegrity(1, user))
 						dullfactor = 0.8
 					else
 						dullfactor = 1.5
-					cont = TRUE
 				if(BCLASS_SMASH)
 					dullfactor = 1.5
-					cont = TRUE
 				if(BCLASS_DRILL)
 					dullfactor = 10
-					cont = TRUE
 				if(BCLASS_BLUNT)
-					cont = TRUE
+					EMPTY_BLOCK_GUARD
 				if(BCLASS_PICK)
 					var/mob/living/miner = user
 					var/mineskill = GET_MOB_SKILL_VALUE_OLD(miner, /datum/attribute/skill/labor/mining)
 					dullfactor = 1.6 - (mineskill * 0.1)
-					cont = TRUE
-			if(!cont)
-				return 0
+				else
+					return 0
 		if(DULLING_PICK) //cannot deal damage if not a pick item. aka rock walls
 			if(user.body_position == LYING_DOWN)
 				to_chat(user, span_warning("I need to stand up to get a proper swing."))
@@ -595,23 +585,25 @@
 			var/damflerp = (dullness_ratio - SHARPNESS_TIER2_THRESHOLD) / (SHARPNESS_TIER1_THRESHOLD - SHARPNESS_TIER2_THRESHOLD)
 			newforce *= damflerp
 			newforce = round(newforce)
+
 	if(user.used_intent.get_chargetime() && user.client?.chargedprog < 100)
 		newforce = newforce * round(user.client?.chargedprog / 100, 0.1)
-	// newforce = round(newforce, 1)
+
 	if(user.body_position == LYING_DOWN)
 		newforce *= 0.5
+
 	if(user.has_status_effect(/datum/status_effect/divine_strike))
 		newforce += 5
-	// newforce is rounded upto the nearest intiger.
-	newforce = round(newforce,1)
-	//This is returning the maximum of the arguments meaning this is to prevent negative values.
-	newforce = max(newforce, 1)
+
 	if(dullness_ratio)
 		if(dullness_ratio < SHARPNESS_TIER2_THRESHOLD && (user.used_intent.blade_class in list(BCLASS_CHOP, BCLASS_CUT, BCLASS_STAB)))
 			var/lerpratio = LERP(0, SHARPNESS_TIER2_THRESHOLD, (dullness_ratio / SHARPNESS_TIER2_THRESHOLD))
 			if(prob(33))
 				to_chat(user, span_info("The blade is dull..."))
 			newforce *= (lerpratio * 2)
+
+	newforce = max(1, round(newforce, DAMAGE_PRECISION))
+
 	return newforce
 
 /mob/living/proc/simple_limb_hit(zone)
@@ -637,43 +629,54 @@
 			return "foreleg"
 	return zone
 
-/obj/item/proc/funny_attack_effects(mob/living/target, mob/living/user, nodmg)
+/obj/item/proc/funny_attack_effects(mob/living/target, mob/living/user)
 	return
 
 /mob/living/attacked_by(obj/item/I, mob/living/user)
 	var/hitlim = simple_limb_hit(user.zone_selected)
 	I.funny_attack_effects(src, user)
-	if(I.force)
-		var/newforce = get_complex_damage(I, user)
-		apply_damage(newforce, I.damtype, def_zone = hitlim)
-		if(I.damtype == BRUTE)
-			next_attack_msg.Cut()
-			if(HAS_TRAIT(src, TRAIT_SIMPLE_WOUNDS))
-				var/datum/wound/crit_wound  = simple_woundcritroll(user.used_intent.blade_class, newforce, user, hitlim)
-				if(crit_wound?.should_embed(I))
-					// throw_alert("embeddedobject", /atom/movable/screen/alert/embeddedobject)
-					simple_add_embedded_object(I, silent = FALSE, crit_message = TRUE)
-					src.grabbedby(user, 1, item_override = I)
-			var/haha = user.used_intent.blade_class
-			if(newforce > 5)
-				if(haha != BCLASS_BLUNT)
-					I.add_mob_blood(src)
-					var/turf/location = get_turf(src)
-					add_splatter_floor(location)
-					if(get_dist(user, src) <= 1)	//people with TK won't get smeared with blood
-						user.add_mob_blood(src)
-						user.adjust_hygiene(-10)
-			if(newforce > 15)
-				if(haha == BCLASS_BLUNT)
-					I.add_mob_blood(src)
-					var/turf/location = get_turf(src)
-					add_splatter_floor(location)
-					if(get_dist(user, src) <= 1)	//people with TK won't get smeared with blood
-						user.add_mob_blood(src)
-						user.adjust_hygiene(-10)
+	if(!I.force)
+		return FALSE
+
+	var/newforce = get_complex_damage(I, user)
+
+	apply_damage(newforce, I.damtype, def_zone = hitlim)
+
+	if(!cmode && !stat && user.m_intent == MOVE_INTENT_SNEAK && (dir == REVERSE_DIR(get_dir(src, user))))
+		var/blunt = (user.used_intent.blade_class == BCLASS_BLUNT)
+		var/attacker_sneaking = GET_MOB_SKILL_VALUE(user, /datum/attribute/skill/misc/sneaking)
+		if((blunt || I.wbalance >= HARD_TO_DODGE) && attacker_sneaking >= 10)
+			next_attack_msg += " [span_userdanger("SNEAK ATTACK!")]"
+			// Get extra damage as a percent of 50% extra based on skill
+			var/percentage = attacker_sneaking / (SKILL_LEVEL_LEGENDARY * 10)
+			newforce += (newforce * 0.5) * percentage
+
+	if(I.damtype == BRUTE)
+		if(HAS_TRAIT(src, TRAIT_SIMPLE_WOUNDS))
+			var/datum/wound/crit_wound  = simple_woundcritroll(user.used_intent.blade_class, newforce, user, hitlim)
+			if(crit_wound?.should_embed(I))
+				// throw_alert("embeddedobject", /atom/movable/screen/alert/embeddedobject)
+				simple_add_embedded_object(I, silent = FALSE, crit_message = TRUE)
+				grabbedby(user, 1, item_override = I)
+		if(newforce > 5)
+			if(user.used_intent.blade_class != BCLASS_BLUNT)
+				I.add_mob_blood(src)
+				var/turf/location = get_turf(src)
+				add_splatter_floor(location)
+				if(get_dist(user, src) <= 1)	//people with TK won't get smeared with blood
+					user.add_mob_blood(src)
+					user.adjust_hygiene(-10)
+		else if(newforce > 15)
+			if(user.used_intent.blade_class == BCLASS_BLUNT)
+				I.add_mob_blood(src)
+				var/turf/location = get_turf(src)
+				add_splatter_floor(location)
+				if(get_dist(user, src) <= 1)	//people with TK won't get smeared with blood
+					user.add_mob_blood(src)
+					user.adjust_hygiene(-10)
+
 	send_item_attack_message(I, user, hitlim)
-	if(I.force)
-		return TRUE
+	return TRUE
 
 /mob/living/simple_animal/attacked_by(obj/item/I, mob/living/user)
 	var/hitlim = simple_limb_hit(user.zone_selected)
@@ -820,17 +823,24 @@
 			return CLAMP(w_class * 6, 10, 100) // Multiply the item's weight class by 6, then clamp the value between 10 and 100
 
 /mob/living/proc/send_item_attack_message(obj/item/I, mob/living/user, hit_area)
+	if(!I.force)
+		return
+
 	var/message_verb = "attacked"
 	if(user.used_intent)
 		message_verb = "[pick(user.used_intent.attack_verb)]"
-	else if(!I.force)
-		return
+
 	var/message_hit_area = ""
 	if(hit_area)
 		message_hit_area = " in the [hit_area]"
+
 	var/attack_message = "[user] [message_verb] [src][message_hit_area] with [I]!"
 	var/attack_message_local = "[user] [message_verb] me[message_hit_area] with [I]!"
-	visible_message("<span class='danger'>[attack_message][next_attack_msg.Join()]</span>",\
-		"<span class='danger'>[attack_message_local][next_attack_msg.Join()]</span>", null, COMBAT_MESSAGE_RANGE)
+	visible_message(
+		span_danger("[attack_message][next_attack_msg.Join()]"),
+		span_danger("[attack_message_local][next_attack_msg.Join()]"),
+		null,
+		COMBAT_MESSAGE_RANGE
+	)
 	next_attack_msg.Cut()
 	return 1

code/game/objects/items/weapons/melee/special.dm

@@ -247,7 +247,7 @@
 	STOP_PROCESSING(SSobj, src)
 	. = ..()
 
-/obj/item/weapon/mace/stunmace/funny_attack_effects(mob/living/target, mob/living/user, nodmg)
+/obj/item/weapon/mace/stunmace/funny_attack_effects(mob/living/target, mob/living/user)
 	. = ..()
 	if(on)
 		target.electrocute_act(5, src)

code/modules/combat/_special_intent.dm

@@ -293,7 +293,7 @@
 		var/obj/item/bodypart/affecting = human_victim.get_bodypart(damage_zone)
 		var/armor_block = human_victim.run_armor_check(damage_zone, damage_type, damage = damage)
 		if(human_victim.apply_damage(damage, damage_type, affecting, armor_block))
-			affecting?.bodypart_attacked_by(damage_class, damage, user, crit_message = TRUE, reduce_crit = 100)
+			affecting?.bodypart_attacked_by(damage_class, damage, user, crit_message = TRUE, modifiers = list(CRIT_MOD_CHANCE = -100))
 			message += "<b> It pierces through to their flesh!</b>"
 			playsound(human_victim, weapon.hitsound, 80, TRUE)
 

code/modules/crafting/alchemy/reagents.dm

@@ -394,7 +394,7 @@ If you want to expand on poisons theres tons of fun effects TG chemistry has tha
 						to_chat(graggar_lover, span_bloody("More... More..."))
 					var/obj/item/bodypart/bp = graggar_lover.get_bodypart()
 					bp?.lingering_pain += 10
-					bp?.bodypart_attacked_by(BCLASS_BLUNT, 12, null, BODY_ZONE_CHEST, crit_message = FALSE, reduce_crit = 10)
+					bp?.bodypart_attacked_by(BCLASS_BLUNT, 12, null, BODY_ZONE_CHEST, crit_message = FALSE, modifiers = list(CRIT_MOD_CHANCE = -10))
 					M.do_jitter_animation(100)
 				if(60)
 					M.do_jitter_animation(150)