Feeling if held items are particularly hot or cold in examine description (#34875)

* Optimize handle_reactions().

* .

* Little bit faster.

* Faster.

* Bit faster.

* .

* Move these earlier.

* Faster.

* Faster.

* Faster.

* Update Chemistry-Holder.dm

* Remove redundant checks.

* Skip null check.

* Sensing if something is hot by touch.

* Update Chemistry-Holder.dm

* Update items.dm

* Update human_defense.dm

don't need these here

* Update shock.dm

* Update items.dm

* Update items.dm

* Update items.dm

---------

Co-authored-by: Hinaichigo <hinaichigo@github.com>

code/game/objects/items.dm

@@ -332,11 +332,46 @@ var/global/objects_thrown_when_explode = FALSE
 	..(user, size, show_name)
 	if(price && price > 0)
 		to_chat(user, "You read '[price] space bucks' on the tag.")
-	if((cant_drop != FALSE) && user.is_holding_item(src)) //Item can't be dropped, and is either in left or right hand!
-		to_chat(user, "<span class='danger'>It's stuck to your hands!</span>")
+	if(user.is_holding_item(src))
+		if(reagents?.total_volume && isliving(user))
+			held_examine_temperature_message(user)
+		if(cant_drop != FALSE) //Item can't be dropped, and is either in left or right hand!
+			to_chat(user, "<span class='danger'>It's stuck to your hands!</span>")
 	if(daemon && daemon.flags & DAEMON_EXAMINE)
 		daemon.examine(user)
 
+/obj/item/proc/held_examine_temperature_message(mob/living/examiner)
+	#define HEAT_LEVEL_SPAN 20
+	var/temperature_delta = (reagents.chem_temp - examiner.bodytemperature) * heat_conductivity ** (1/3) //Cubed root to skew it towards being perceptible.
+	if (ishuman(examiner))
+		var/mob/living/carbon/human/H = examiner
+		temperature_delta *= (H.gloves ? H.gloves.heat_conductivity ** (1/3) : 1)
+	var/safetemp_excursion = examiner.get_safe_temperature_excursion(examiner.bodytemperature + temperature_delta)
+	if (!examiner.feels_pain() || examiner.has_painkillers())
+		safetemp_excursion = 0
+	else if(safetemp_excursion > 0)
+		safetemp_excursion = min(ceil(safetemp_excursion / HEAT_LEVEL_SPAN), 3)
+	else if (safetemp_excursion < 0)
+		safetemp_excursion = max(round(safetemp_excursion / HEAT_LEVEL_SPAN), -3)
+	switch (safetemp_excursion)
+		if (0)
+			if (temperature_delta >= HEAT_LEVEL_SPAN)
+				to_chat(examiner, "<span class='notice'>It feels warm.</span>")
+			else if(abs(temperature_delta) >= HEAT_LEVEL_SPAN)
+				to_chat(examiner, "<span class='notice'>It feels cool.</span>")
+		if (1)
+			to_chat(examiner, "<span class='warning'>It feels very hot.</span>")
+		if (-1)
+			to_chat(examiner, "<span class='warning'>It feels very cold.</span>")
+		if (2)
+			to_chat(examiner, "<span class='warning'>It feels searing hot.</span>")
+		if (-2)
+			to_chat(examiner, "<span class='warning'>It feels freezing cold.</span>")
+		if (3)
+			to_chat(examiner, "<span class='warning'>It feels blisteringly hot.</span>")
+		if (-3)
+			to_chat(examiner, "<span class='warning'>It feels piercingly cold.</span>")
+	#undef HEAT_LEVEL_SPAN
 
 /obj/item/attack_ai(mob/user as mob)
 	..()

code/modules/mob/living/carbon/human/human_defense.dm

@@ -593,4 +593,4 @@ emp_act
 		return PACID
 
 /mob/living/carbon/human/beam_defense(var/obj/effect/beam/B)
-	return is_wearing_item(/obj/item/clothing/suit/reticulatedvest) ? 0.4 : 1
+	return is_wearing_item(/obj/item/clothing/suit/reticulatedvest) ? 0.4 : 1

code/modules/mob/living/carbon/shock.dm

@@ -46,10 +46,9 @@
 /mob/living/carbon/proc/handle_shock() //Currently only used for humans
 	update_pain_level()
 
-
-/mob/living/carbon/proc/total_painkillers()
+/mob/living/proc/total_painkillers()
 	for(var/datum/reagent/R in reagents.reagent_list)
 		. += R.pain_resistance
 
-/mob/living/carbon/proc/has_painkillers()
+/mob/living/proc/has_painkillers()
 	return total_painkillers() > 0 

code/modules/mob/living/helper_procs.dm

@@ -44,3 +44,33 @@ default behaviour is:
 /mob/living/proc/isDeadorDying()	//returns 1 if dead or in crit
 	if(stat == DEAD || health <= config.health_threshold_crit)
 		return TRUE
+
+/mob/living/proc/get_safe_temperature_excursion(the_temp)
+	//Returns how many degrees K a temperature is outside of the safe range the mob can tolerate. returns 0 if within the safe range. can be negative for cold.
+	return 0
+
+/mob/living/simple_animal/get_safe_temperature_excursion(the_temp)
+	if (the_temp > maxbodytemp)
+		return the_temp - maxbodytemp
+	else if (the_temp < minbodytemp)
+		return the_temp - minbodytemp
+	return 0
+
+/mob/living/carbon/monkey/get_safe_temperature_excursion(the_temp)
+	if (the_temp > BODYTEMP_HEAT_DAMAGE_LIMIT)
+		return the_temp - BODYTEMP_HEAT_DAMAGE_LIMIT
+	else if (the_temp < BODYTEMP_COLD_DAMAGE_LIMIT)
+		return the_temp - BODYTEMP_COLD_DAMAGE_LIMIT
+	return 0
+
+/mob/living/carbon/human/get_safe_temperature_excursion(the_temp)
+	if (species)
+		if (the_temp > species.heat_level_1)
+			return the_temp - species.heat_level_1
+		else if (the_temp < species.cold_level_1)
+			return the_temp - species.cold_level_1
+	else if (the_temp > BODYTEMP_HEAT_DAMAGE_LIMIT)
+		return the_temp - BODYTEMP_HEAT_DAMAGE_LIMIT
+	else if (the_temp < BODYTEMP_COLD_DAMAGE_LIMIT)
+		return the_temp - BODYTEMP_COLD_DAMAGE_LIMIT
+	return 0