[MIRROR] Properly fixes Mending Touch (#28680)

* Properly fixes Mending Touch (#84569)

## About The Pull Request

fixed MT hurting simplemobs

Fixed the multiplier bug properly (last fix overrode coefficients),

Improved its wound effects, allowing it to transfer severe and critical
wounds if upgraded.

Allowed it to transfer blood between the patient and doctor as well. It
adds a teensy bit of toxin damage if the blood types are incompatible.

Added balloon alerts on various failure states.

Added an inability to use the mutation if your active arm is inorganic.

Improved the code of the mutation overall, improving and updating the
comments.

## Why It's Good For The Game

> Fixed the multiplier bug properly (last fix overrode coefficients),

I forgor to draft it... in my defence it hadn't been approved or been up
for 24 hours so I didn't expect a speedmerg.

> Improved its wound effects, allowing it to transfer severe and
critical wounds if upgraded.

Felt lacking that it couldn't transfer severe wounds, or critical ones
if you went the extra mile.

> Allowed it to transfer blood between the patient and doctor as well.
It adds a teensy bit of toxin damage if the blood types are
incompatible.

Blood is an important part of medbay now, it's wack that I didn't gave
it that before. Also the tox thing is funny.

> Added balloon alerts on various failure states.

Player feedback : GOOD

> Added an inability to use the mutation if your active arm is
inorganic.

How are you gonna transfer wounds to you if you have a robot arm?

## Changelog

🆑
fix: fixed MT hurting simplemobs
fix: Fixed the multiplier bug properly (last fix overrode coefficients),
add: Improved its wound effects, allowing it to transfer severe and
critical wounds if upgraded.
add: Allowed it to transfer blood between the patient and doctor as
well. It adds a teensy bit of toxin damage if the blood types are
incompatible.
imageadd: Added balloon alerts on various failure states.
add: Added an inability to use the mutation if your active arm is
inorganic.
code: Improved the code of the mutation overall, improving and updating
the comments.
/🆑

* Properly fixes Mending Touch

---------

Co-authored-by: carlarctg <53100513+carlarctg@users.noreply.github.com>

code/datums/mutations/touch.dm

@@ -107,10 +107,10 @@
 	if(!istype(to_modify)) // null or invalid
 		return
 
-	// More healing if powered up.
-	to_modify.heal_multiplier = GET_MUTATION_POWER(src)
-	// Less pain if synchronized.
-	to_modify.pain_multiplier = GET_MUTATION_SYNCHRONIZER(src)
+	// Transfers more damage if strengthened. (1.5 with power chromosome)
+	to_modify.power_coefficient = GET_MUTATION_POWER(src)
+	// Halves transferred damage if synchronized. (0.5 with synchronizer chromosome)
+	to_modify.synchronizer_coefficient = GET_MUTATION_SYNCHRONIZER(src)
 
 /datum/action/cooldown/spell/touch/lay_on_hands
 	name = "Mending Touch"
@@ -127,36 +127,55 @@
 	hand_path = /obj/item/melee/touch_attack/lay_on_hands
 	draw_message = span_notice("You ready your hand to transfer injuries to yourself.")
 	drop_message = span_notice("You lower your hand.")
-	/// Multiplies the amount healed, without increasing the received damage.
+	/// Multiplies the amount healed.
 	var/heal_multiplier = 1
-	/// Multiplies the incoming pain from healing.
+	/// Multiplies the incoming pain from healing. (Halved with synchronizer chromosome)
 	var/pain_multiplier = 1
 	/// Icon used for beaming effect
 	var/beam_icon = "blood"
+	/// The mutation's power coefficient.
+	var/power_coefficient = 1
+	/// The mutation's synchronizer coefficient.
+	var/synchronizer_coefficient = 1
+
+/datum/action/cooldown/spell/touch/lay_on_hands/create_hand(mob/living/carbon/cast_on)
+	. = ..()
+	if(!.)
+		return .
+	var/obj/item/bodypart/transfer_limb = cast_on.get_active_hand()
+	if(IS_ROBOTIC_LIMB(transfer_limb))
+		to_chat(cast_on, span_notice("You fail to channel your mending powers through your inorganic hand."))
+		return FALSE
+
+	return TRUE
 
 /datum/action/cooldown/spell/touch/lay_on_hands/cast_on_hand_hit(obj/item/melee/touch_attack/hand, atom/victim, mob/living/carbon/mendicant)
 
 	var/mob/living/hurtguy = victim
 
+	heal_multiplier = initial(heal_multiplier) * power_coefficient
+	pain_multiplier = initial(pain_multiplier) * synchronizer_coefficient
+
+	// Message to show on a succesful heal if the healer has a special pacifism interaction with the mutation.
+	var/peaceful_message = null
+
 	// Heal more, hurt a bit more.
 	// If you crunch the numbers it sounds crazy good,
 	// but I think that's a fair reward for combining the efforts of Genetics, Medbay, and Mining to reach a hidden mechanic.
 	if(HAS_TRAIT_FROM(mendicant, TRAIT_HIPPOCRATIC_OATH, HIPPOCRATIC_OATH_TRAIT))
-		heal_multiplier = 2
-		pain_multiplier = 0.5
-		to_chat(mendicant, span_green("You can feel the magic of the Rod of Aesculapius aiding your efforts!"))
+		heal_multiplier *= 2
+		pain_multiplier *= 0.5
+		peaceful_message = span_boldnotice("You can feel the magic of the Rod of Aesculapius aiding your efforts!")
 		beam_icon = "sendbeam"
 		var/obj/item/rod_of_asclepius/rod = locate() in mendicant.contents
 		if(rod)
 			rod.add_filter("cool_glow", 2, list("type" = "outline", "color" = COLOR_VERY_PALE_LIME_GREEN, "size" = 1.25))
 			addtimer(CALLBACK(rod, TYPE_PROC_REF(/datum, remove_filter), "cool_glow"), 6 SECONDS)
 
-
-	// If a normal pacifist, heal and hurt more!
+	// If a normal pacifist, transfer more.
 	else if(HAS_TRAIT(mendicant, TRAIT_PACIFISM))
-		heal_multiplier = 1.75
-		pain_multiplier = 1.75
-		to_chat(mendicant, span_green("Your peaceful nature helps you guide all the pain to yourself."))
+		heal_multiplier *= 1.75
+		peaceful_message = span_boldnotice("Your peaceful nature helps you guide all the pain to yourself.")
 
 	var/success
 	if(iscarbon(hurtguy))
@@ -164,6 +183,13 @@
 	else
 		success = do_simple_heal(mendicant, hurtguy, heal_multiplier, pain_multiplier)
 
+	// No healies in the end, cancel
+	if(!success)
+		return FALSE
+
+	if(peaceful_message)
+		to_chat(mendicant, peaceful_message)
+
 	// Both types can be ignited (technically at least), so we can just do this here.
 	if(hurtguy.fire_stacks > 0)
 		mendicant.set_fire_stacks(hurtguy.fire_stacks * pain_multiplier, remove_wet_stacks = TRUE)
@@ -171,10 +197,6 @@
 			mendicant.ignite_mob()
 			hurtguy.extinguish_mob()
 
-	// No healies in the end, cancel
-	if(!success)
-		return FALSE
-
 	mendicant.Beam(hurtguy, icon_state = beam_icon, time = 0.5 SECONDS)
 	beam_icon = initial(beam_icon)
 
@@ -182,7 +204,7 @@
 	mendicant.update_damage_overlays()
 
 	hurtguy.visible_message(span_notice("[mendicant] lays hands on [hurtguy]!"))
-	to_chat(target, span_boldnotice("[mendicant] lays hands on you, healing you!"))
+	to_chat(hurtguy, span_boldnotice("[mendicant] lays hands on you, healing you!"))
 	new /obj/effect/temp_visual/heal(get_turf(hurtguy), COLOR_VERY_PALE_LIME_GREEN)
 	return success
 
@@ -202,6 +224,7 @@
 			mendicant_organic_limbs += possible_limb
 	// None? Gtfo
 	if(!length(mendicant_organic_limbs))
+		mendicant.balloon_alert(mendicant, "no organic limbs!")
 		return .
 
 	// Try to use our active hand, otherwise pick at random
@@ -218,7 +241,8 @@
 		hurtguy.adjustFireLoss(-burn_to_heal)
 		. = TRUE
 
-	return .
+	if(!.)
+		hurtguy.balloon_alert(mendicant, "unhurt!")
 
 /datum/action/cooldown/spell/touch/lay_on_hands/proc/do_complicated_heal(mob/living/carbon/mendicant, mob/living/carbon/hurtguy, heal_multiplier, pain_multiplier)
 
@@ -232,8 +256,12 @@
 			mendicant_organic_limbs += possible_limb
 
 	// If we have no organic available limbs just give up.
-	if(!length(mendicant_organic_limbs) || !length(hurt_limbs))
-		return
+	if(!length(mendicant_organic_limbs))
+		mendicant.balloon_alert(mendicant, "no organic limbs!")
+		return .
+	if(!length(hurt_limbs))
+		hurtguy.balloon_alert(mendicant, "no damaged organic limbs!")
+		return .
 
 	// Counter to make sure we don't take too much from separate limbs
 	var/total_damage_healed = 0
@@ -244,28 +272,71 @@
 		if(!(mendicant_transfer_limb in mendicant_organic_limbs))
 			mendicant_transfer_limb = pick(mendicant_organic_limbs)
 
-		// Transfer at most 35 damage by default.
+		// Transfer at most 35 damage, by default.
 		var/brute_damage = min(affected_limb.brute_dam, 35 * heal_multiplier)
 		// no double dipping
 		var/burn_damage = min(affected_limb.burn_dam, (35 * heal_multiplier) - brute_damage)
 		if((brute_damage || burn_damage) && total_damage_healed < (35 * heal_multiplier))
-			total_damage_healed = brute_damage + burn_damage
+			total_damage_healed += brute_damage + burn_damage
 			. = TRUE
+			var/brute_taken = brute_damage * pain_multiplier
+			var/burn_taken = burn_damage * pain_multiplier
 			// Heal!
-			affected_limb.heal_damage(brute_damage * heal_multiplier, burn_damage * heal_multiplier, required_bodytype = BODYTYPE_ORGANIC)
+			affected_limb.heal_damage(brute_damage, burn_damage, required_bodytype = BODYTYPE_ORGANIC)
 			// Hurt!
-			mendicant_transfer_limb.receive_damage(brute_damage * pain_multiplier, burn_damage * pain_multiplier, forced = TRUE, wound_bonus = CANT_WOUND)
+			mendicant_transfer_limb.receive_damage(brute_taken, burn_taken, forced = TRUE, wound_bonus = CANT_WOUND)
 
 		// Force light wounds onto you.
 		for(var/datum/wound/iter_wound as anything in affected_limb.wounds)
-			if(iter_wound.severity > WOUND_SEVERITY_MODERATE)
-				continue
+			switch(iter_wound.severity)
+				if(WOUND_SEVERITY_SEVERE) // half and half
+					if(prob(50 * heal_multiplier))
+						continue
+				if(WOUND_SEVERITY_CRITICAL)
+					if(heal_multiplier < 1.5) // need buffs to transfer crit wounds
+						continue
 			. = TRUE
 			iter_wound.remove_wound()
 			iter_wound.apply_wound(mendicant_transfer_limb)
 
+	if(HAS_TRAIT(mendicant, TRAIT_NOBLOOD))
+		return .
 
-	return .
+	// 10% base
+	var/max_blood_transfer = (BLOOD_VOLUME_NORMAL * 0.10) * heal_multiplier
+	// Too little blood
+	if(hurtguy.blood_volume < BLOOD_VOLUME_NORMAL)
+		var/max_blood_to_hurtguy = min(mendicant.blood_volume, BLOOD_VOLUME_NORMAL - hurtguy.blood_volume)
+		var/blood_to_hurtguy = min(max_blood_transfer, max_blood_to_hurtguy)
+		if(!blood_to_hurtguy)
+			return .
+		// We ignore incompatibility here.
+		mendicant.transfer_blood_to(hurtguy, blood_to_hurtguy, forced = TRUE, ignore_incompatibility = TRUE)
+		to_chat(mendicant, span_notice("Your veins (and brain) feel a bit lighter."))
+		. = TRUE
+		// Because we do our own spin on it!
+		if(hurtguy.get_blood_compatibility(mendicant) == FALSE)
+			hurtguy.adjustToxLoss((blood_to_hurtguy * 0.1) * pain_multiplier) // 1 dmg per 10 blood
+			to_chat(hurtguy, span_notice("Your veins feel thicker, but they itch a bit."))
+		else
+			to_chat(hurtguy, span_notice("Your veins feel thicker!"))
+
+	// Too MUCH blood
+	if(hurtguy.blood_volume > BLOOD_VOLUME_MAXIMUM)
+		var/max_blood_to_mendicant = BLOOD_VOLUME_EXCESS - hurtguy.blood_volume
+		var/blood_to_mendicant = min(max_blood_transfer, max_blood_to_mendicant)
+		// mender always gonna have blood
+
+		// We ignore incompatibility here.
+		hurtguy.transfer_blood_to(mendicant, hurtguy.blood_volume - BLOOD_VOLUME_EXCESS, forced = TRUE, ignore_incompatibility = TRUE)
+		to_chat(hurtguy, span_notice("Your veins don't feel quite so swollen anymore."))
+		. = TRUE
+		// Because we do our own spin on it!
+		if(mendicant.get_blood_compatibility(hurtguy) == FALSE)
+			mendicant.adjustToxLoss((blood_to_mendicant * 0.1) * pain_multiplier) // 1 dmg per 10 blood
+			to_chat(mendicant, span_notice("Your veins swell and itch!"))
+		else
+			to_chat(mendicant, span_notice("Your veins swell!"))
 
 /obj/item/melee/touch_attack/lay_on_hands
 	name = "mending touch"

code/modules/mob/living/blood.dm

@@ -227,7 +227,7 @@
 ****************************************************/
 
 //Gets blood from mob to a container or other mob, preserving all data in it.
-/mob/living/proc/transfer_blood_to(atom/movable/AM, amount, forced)
+/mob/living/proc/transfer_blood_to(atom/movable/AM, amount, forced, ignore_incompatibility)
 	if(!blood_volume || !AM.reagents)
 		return FALSE
 	if(blood_volume < BLOOD_VOLUME_BAD && !forced)
@@ -254,7 +254,7 @@
 						if((D.spread_flags & DISEASE_SPREAD_SPECIAL) || (D.spread_flags & DISEASE_SPREAD_NON_CONTAGIOUS))
 							continue
 						C.ForceContractDisease(D)
-				if(!(blood_data["blood_type"] in get_safe_blood(C.dna.blood_type)))
+				if(!(blood_data["blood_type"] in get_safe_blood(C.dna.blood_type)) && !(ignore_incompatibility))
 					C.reagents.add_reagent(/datum/reagent/toxin, amount * 0.5)
 					return TRUE
 
@@ -349,6 +349,15 @@
 	if(safe)
 		. = safe
 
+/**
+ * Returns TRUE if src is compatible with donor's blood, otherwise FALSE.
+ * * donor: Carbon mob, the one that is donating blood.
+ */
+/mob/living/carbon/proc/get_blood_compatibility(mob/living/carbon/donor)
+	var/patient_blood_data = get_blood_data(get_blood_id())
+	var/donor_blood_data = donor.get_blood_data(donor.get_blood_id())
+	return donor_blood_data["blood_type"] in get_safe_blood(patient_blood_data["blood_type"])
+
 //to add a splatter of blood or other mob liquid.
 /mob/living/proc/add_splatter_floor(turf/T, small_drip)
 	if(get_blood_id() != /datum/reagent/blood)