Diona nymphs can now run correctly (#19665)

Diona nymphs can now run correctly, without a weird empty stamina bar,
and stopping as appropriate when their stamina (health) is low, with a
message.

Fixes #14038

code/modules/mob/living/carbon/alien/diona/diona_nymph.dm

@@ -26,6 +26,7 @@
 	meat_amount = 2
 	maxHealth = 50
 	health = 50
+	max_stamina = -1
 	pass_flags = PASSTABLE
 
 	// Decorative head flower.
@@ -377,3 +378,9 @@
 	if (status_flags & GODMODE)
 		return
 	health = min(health - amount, maxHealth)
+
+/mob/living/carbon/alien/diona/getHalLoss()
+	if(status_flags & GODMODE)
+		return
+
+	return max((maxHealth - health), 0)

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

@@ -668,7 +668,7 @@
 	if(H.is_drowsy())
 		cost *= 1.25
 	if (H.stamina == -1)
-		LOG_DEBUG("Error: Species with special sprint mechanics has not overridden cost function.")
+		stack_trace("Error: Species with special sprint mechanics has not overridden cost function.")
 		return 0
 
 	var/obj/item/organ/internal/augment/calf_override/C = H.internal_organs_by_name[BP_AUG_CALF_OVERRIDE]

code/modules/mob/living/carbon/human/species/station/diona/diona.dm

@@ -182,6 +182,23 @@
 		if((!D.client && !D.mind) || D.stat == DEAD)
 			qdel(D)
 
+//This handles nymphs, which are the only diona specie that can run, since they don't breathe they just take pain damage instead
+/datum/species/diona/handle_sprint_cost(mob/living/carbon/human/H, cost, pre_move)
+	if(!pre_move)
+		H.adjustHalLoss(cost*0.3)
+		H.updatehealth()
+
+	if(H.getHalLoss() > (H.maxHealth*0.6))
+		var/shock = H.get_shock()
+		if(prob(shock * 2))
+			to_chat(H, SPAN_DANGER("You feel a sharp pain in your nervous system! You can't run anymore, or you might die!"))
+			H.m_intent = M_WALK
+
+	if(!pre_move)
+		H.hud_used.move_intent.update_move_icon(H)
+	return 1
+
+
 /datum/species/diona/after_equip(mob/living/carbon/human/H, visualsOnly, datum/job/J)
 	. = ..()
 	var/obj/item/storage/box/survival/SB = locate() in H