Xeno strain resetting (#7841)

# About the pull request
Allows xenos to reset their strain, first use is free after that it can
be used every 40 minutes
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# Explain why it's good for the game
Allows players to change their strain if they do not enjoy playing it
anymore or the round has went on for long enough it became basically
useless - happier players >> profit. (You could also make a point for
new players that accidently clicked a strain out of curiosity and now
want to reset it)
# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>

Put screenshots and videos here with an empty line between the
screenshots and the `<details>` tags.

</details>


# Changelog
:cl:
add: Xenomorphs can now reset their strain, first use is free then it
can be done once every 40 minutes.
/:cl:

---------

Co-authored-by: Zenith <[email protected]>
Co-authored-by: Blundir <[email protected]>
Co-authored-by: cmss13-ci[bot] <180991813+cmss13-ci[bot]@users.noreply.github.com>

code/__DEFINES/keybinding.dm

@@ -167,6 +167,7 @@
 #define COMSIG_KB_XENO_HIDE "keybinding_hide"
 #define COMSIG_KB_XENO_EVOLVE "keybinding_evolve"
 #define COMSIG_KB_XENO_PURCHASE_STRAIN "keybinding_purchase_strain"
+#define COMSIG_KB_XENO_RESET_STRAIN "keybinding_reset_strain"
 
 // Yautja
 

code/datums/keybinding/xenomorph.dm

@@ -221,3 +221,18 @@
 
 	var/mob/living/carbon/xenomorph/current_xeno = user?.mob
 	current_xeno.purchase_strain()
+
+/datum/keybinding/xenomorph/reset_strain
+	hotkey_keys = list("Unbound")
+	classic_keys = list("Unbound")
+	name = "reset_strain"
+	full_name = "Reset Strain"
+	keybind_signal = COMSIG_KB_XENO_RESET_STRAIN
+
+/datum/keybinding/xenomorph/reset_strain/down(client/user)
+	. = ..()
+	if(.)
+		return
+
+	var/mob/living/carbon/xenomorph/current_xeno = user?.mob
+	current_xeno.reset_strain()

code/modules/mob/living/carbon/xenomorph/Evolution.dm

@@ -309,27 +309,39 @@
 
 	SEND_SIGNAL(src, COMSIG_XENO_DEEVOLVE)
 
+	var/mob/living/carbon/xenomorph/new_xeno = transmute(newcaste)
+	if(new_xeno)
+		log_game("EVOLVE: [key_name(src)] de-evolved into [new_xeno].")
+
+	return
+
+/mob/living/carbon/xenomorph/proc/transmute(newcaste)
+	// We have to delete the organ before creating the new xeno because all old_xeno contents are dropped to the ground on Initalize()
 	var/obj/item/organ/xeno/organ = locate() in src
 	if(!isnull(organ))
 		qdel(organ)
 
 	var/level_to_switch_to = get_vision_level()
 	var/xeno_type = GLOB.RoleAuthority.get_caste_by_text(newcaste)
-
 	var/mob/living/carbon/xenomorph/new_xeno = new xeno_type(get_turf(src), src)
-
+	
 	if(!istype(new_xeno))
-		//Something went horribly wrong!
+		//Something went horribly wrong
 		to_chat(src, SPAN_WARNING("Something went terribly wrong here. Your new xeno is null! Tell a coder immediately!"))
 		if(new_xeno)
 			qdel(new_xeno)
-		return
+
+		if(organ_value != 0)
+			organ = new()
+			organ.forceMove(src)
+			organ.research_value = organ_value
+			organ.caste_origin = caste_type
+			organ.icon_state = get_organ_icon()
+		return FALSE
 
 	new_xeno.built_structures = built_structures.Copy()
 	built_structures = null
 
-	log_game("EVOLVE: [key_name(src)] de-evolved into [new_xeno].")
-
 	if(mind)
 		mind.transfer_to(new_xeno)
 	else
@@ -363,7 +375,8 @@
 	SSround_recording.recorder.track_player(new_xeno)
 
 	qdel(src)
-	return
+
+	return new_xeno
 
 /mob/living/carbon/xenomorph/proc/can_evolve(castepick, potential_queens)
 	var/selected_caste = GLOB.xeno_datum_list[castepick]?.type

code/modules/mob/living/carbon/xenomorph/Xenomorph.dm

@@ -208,6 +208,7 @@
 	var/armor_integrity_modifier = 0
 
 	var/list/modifier_sources
+	COOLDOWN_DECLARE(next_strain_reset)
 
 	//////////////////////////////////////////////////////////////////
 	//

code/modules/mob/living/carbon/xenomorph/abilities/queen/queen_powers.dm

@@ -63,61 +63,15 @@
 
 	SEND_SIGNAL(target_xeno, COMSIG_XENO_DEEVOLVE)
 
-	var/obj/item/organ/xeno/organ = locate() in target_xeno
-	if(!isnull(organ))
-		qdel(organ)
+	var/mob/living/carbon/xenomorph/new_xeno = target_xeno.transmute(newcaste)
 
-	var/level_to_switch_to = target_xeno.get_vision_level()
-	var/xeno_type = GLOB.RoleAuthority.get_caste_by_text(newcaste)
+	if(new_xeno)
+		message_admins("[key_name_admin(user_xeno)] has deevolved [key_name_admin(target_xeno)]. Reason: [reason]")
+		log_admin("[key_name_admin(user_xeno)] has deevolved [key_name_admin(target_xeno)]. Reason: [reason]")
 
-	//From there, the new xeno exists, hopefully
-	var/mob/living/carbon/xenomorph/new_xeno = new xeno_type(get_turf(target_xeno), target_xeno)
+		if(user_xeno.hive.living_xeno_queen && user_xeno.hive.living_xeno_queen.observed_xeno == target_xeno)
+			user_xeno.hive.living_xeno_queen.overwatch(new_xeno)
 
-	if(!istype(new_xeno))
-		//Something went horribly wrong!
-		to_chat(user_xeno, SPAN_WARNING("Something went terribly wrong here. Your new xeno is null! Tell a coder immediately!"))
-		if(new_xeno)
-			qdel(new_xeno)
-		return
-
-	new_xeno.built_structures = target_xeno.built_structures.Copy()
-	target_xeno.built_structures = null
-
-	if(target_xeno.mind)
-		target_xeno.mind.transfer_to(new_xeno)
-	else
-		new_xeno.key = target_xeno.key
-		if(new_xeno.client)
-			new_xeno.client.change_view(GLOB.world_view_size)
-			new_xeno.client.pixel_x = 0
-			new_xeno.client.pixel_y = 0
-
-	//Regenerate the new mob's name now that our player is inside
-	new_xeno.generate_name()
-	if(new_xeno.client)
-		new_xeno.set_lighting_alpha(level_to_switch_to)
-
-	// If the player has lost the Deevolve verb before, don't allow them to do it again
-	if(!(/mob/living/carbon/xenomorph/verb/Deevolve in target_xeno.verbs))
-		remove_verb(new_xeno, /mob/living/carbon/xenomorph/verb/Deevolve)
-
-	new_xeno.visible_message(SPAN_XENODANGER("A [new_xeno.caste.caste_type] emerges from the husk of \the [target_xeno]."), \
-	SPAN_XENODANGER("[user_xeno] makes us regress into your previous form."))
-
-	if(user_xeno.hive.living_xeno_queen && user_xeno.hive.living_xeno_queen.observed_xeno == target_xeno)
-		user_xeno.hive.living_xeno_queen.overwatch(new_xeno)
-
-	message_admins("[key_name_admin(user_xeno)] has deevolved [key_name_admin(target_xeno)]. Reason: [reason]")
-	log_admin("[key_name_admin(user_xeno)] has deevolved [key_name_admin(target_xeno)]. Reason: [reason]")
-
-	target_xeno.transfer_observers_to(new_xeno)
-
-	if(GLOB.round_statistics && !new_xeno.statistic_exempt)
-		GLOB.round_statistics.track_new_participant(target_xeno.faction, -1) //so an evolved xeno doesn't count as two.
-	SSround_recording.recorder.stop_tracking(target_xeno)
-	SSround_recording.recorder.track_player(new_xeno)
-
-	qdel(target_xeno)
 	return
 
 /datum/action/xeno_action/onclick/remove_eggsac/use_ability(atom/A)

code/modules/mob/living/carbon/xenomorph/strains/xeno_strain.dm

@@ -61,7 +61,6 @@
 	// Override with custom behaviour.
 	return
 
-
 /mob/living/carbon/xenomorph/verb/purchase_strain()
 	set name = "Purchase Strain"
 	set desc = "Purchase a strain for yourself"
@@ -99,15 +98,49 @@
 		// If it applied successfully, add it to the logs.
 		log_strain("[name] purchased strain '[strain_instance.type]'")
 
+/mob/living/carbon/xenomorph/verb/reset_strain()
+	set name = "Reset Strain"
+	set desc = "Reset your strain"
+	set category = "Alien"
+
+	// Firstly, make sure the xeno is actually able to take a strain.
+	if(!can_take_strain(reset = TRUE))
+		return
+
+	if(!COOLDOWN_FINISHED(src, next_strain_reset))
+		to_chat(src, SPAN_WARNING("We lack the strength to reset our strain. We will be able to reset it in [round((next_strain_reset - world.time) / 600, 1)] minutes"))
+		return
+
+	// Show the user the strain's description, and double check that they want it.
+	if(tgui_alert(src, "Are you sure?", "Reset Strain", list("Yes", "No")) != "Yes")
+		return
+
+	// One more time after they confirm.
+	if(!can_take_strain(reset = TRUE))
+		return
+
+	var/mob/living/carbon/xenomorph/new_xeno = transmute(caste_type)
+	if(!new_xeno)
+		return
+
+	new_xeno.xeno_jitter(1.5 SECONDS)
+	// If it applied successfully, add it to the logs.
+	log_strain("[new_xeno.name] reset their strain.")
+	COOLDOWN_START(new_xeno, next_strain_reset, 40 MINUTES)
+
 /// Is this xeno currently able to take a strain?
-/mob/living/carbon/xenomorph/proc/can_take_strain()
+/mob/living/carbon/xenomorph/proc/can_take_strain(reset=FALSE)
 	if(!length(caste.available_strains) || !check_state(TRUE))
 		return FALSE
 
-	if(strain)
+	if(strain && !reset)
 		to_chat(src, SPAN_WARNING("We have already chosen a strain."))
 		return FALSE
 
+	if(!strain && reset)
+		to_chat(src, SPAN_WARNING("You must first pick a strain before resetting it."))
+		return FALSE
+
 	if(is_ventcrawling)
 		to_chat(src, SPAN_WARNING("This place is too constraining to take a strain."))
 		return FALSE