Fixing client eye (#18577)

* signal foundation

* reset_perspective implemented

* you too

* setting mob

* no

* fix

* tweak

* remote view element

* these too

* use element

* cleanup more manual code

* fix element

* mutation signal

* handle being dropped from holders, and fix pai hud

* handle qdel

* it's a component now

* ugly holder fix

* another fix

* follow view target

* item remote view

* doc update

* unneeded

* this needs a recode to work better

* many fixes

* these are all unneeded

* almost working viewerlist remotes

* this uses component too

* this needs to die to it's item

* don't allow spamming tgui menus

* tg style args

* fixing behaviors

* fuk

* working view release from holders

* only final matters

* comment order and disposal fix

* cryotube loc fix

* no mob should reset its view every life tick

* major improvements

* still forbid z level change even if we allow moving

* this too

* don't doubledip

* qdel on self is unneeded

* wipe remote views on logout

* vore bellies need to manually clear views

* fixAI hud

* belly release fixes

* cannot use binoculars in a vore belly

* pai card can be picked up and dropped correctly

* ventcrawl fix and distracted fix

* this is better

* forcemove

* vr console fix

* use flag for this

* belly stuff

* various cleanups

* oops

* fixes statue spell

* unneeded perspective clear

* automatic instead

* continued cleanup

* that was dumb

* needed

* none of this works

* are these even needed

* lets lock down to these

* lets try to make this work

* extremely close to working

* needs to solve final pai issues

* mob eye change signal

* Revert "mob eye change signal"

This reverts commit eedd5da934.

* significant progress

* safety

* expected to be not null

* likely not needed

* don't spam component changes

* endview on logout

* accessors

* egg fixing

* Revert "egg fixing"

This reverts commit 6a54049c69.

* getting closer

* even closer

* needs type

* close...

* extremely close to working

* fixing pai stuff

* this too

* promising fixes

* docs

* this is recursive move's responsibility tbh

* unneeded now

* oops

* better decouple

* topmost check

* cleanup

* holder released from egg fix

* pai fix for reset view

* debug info

* some better pai ejection code

* better way

* unneeded

* needs to be null

* better vision restore

* use correct handling

* no longer needed

* required

* handle decouple on mecha too

* name clarity

* do not allow double dipping zoom items

* ethereal jaunt needs a full cleanup later

* fix blackscreen flicker

* remove set machine from pda

* Update code/game/objects/items.dm

* Update code/game/objects/items.dm

* Update code/game/objects/items.dm

* Update code/game/objects/items.dm

---------

Co-authored-by: Cameron Lennox <killer65311@gmail.com>

code/modules/mob/mob.dm

@@ -244,19 +244,69 @@
 /mob/proc/restrained()
 	return
 
-/mob/proc/reset_view(atom/A)
-	if (client)
-		if (istype(A, /atom/movable))
-			client.perspective = EYE_PERSPECTIVE
-			client.eye = A
-		else
-			if (isturf(loc))
-				client.eye = client.mob
-				client.perspective = MOB_PERSPECTIVE
-			else
+/**
+ * Reset the attached clients perspective (viewpoint)
+ *
+ * reset_perspective() set eye to common default : mob on turf, loc otherwise. If the client mob is inside an object with REMOTEVIEW_ON_ENTER, it will restart that object's remote view.
+ * reset_perspective(thing) set the eye to the thing (if it's equal to current default reset to mob perspective). This ignores REMOTEVIEW_ON_ENTER, and forces focus to the mob.
+ */
+/mob/proc/reset_perspective(atom/new_eye)
+	SHOULD_CALL_PARENT(TRUE)
+	if(!client)
+		return
+
+	if(new_eye)
+		if(ismovable(new_eye))
+			//Set the new eye unless it's us
+			if(new_eye != src)
 				client.perspective = EYE_PERSPECTIVE
-				client.eye = loc
+				client.set_eye(new_eye)
+			else
+				client.set_eye(client.mob)
+				client.perspective = MOB_PERSPECTIVE
+
+		else if(isturf(new_eye))
+			//Set to the turf unless it's our current turf
+			if(new_eye != loc)
+				client.perspective = EYE_PERSPECTIVE
+				client.set_eye(new_eye)
+			else
+				client.set_eye(client.mob)
+				client.perspective = MOB_PERSPECTIVE
+		else
+			return TRUE //no setting eye to stupid things like areas or whatever
+	else
+		//If we return focus to our own mob, but we are still inside something with an inherent remote view. Restart it.
+		if(restore_remote_views())
+			return TRUE
+		//Reset to common defaults: mob if on turf, otherwise current loc
+		if(isturf(loc))
+			client.set_eye(client.mob)
+			client.perspective = MOB_PERSPECTIVE
+		else
+			client.perspective = EYE_PERSPECTIVE
+			client.set_eye(loc)
+	/// Signal sent after the eye has been successfully updated, with the client existing.
+	SEND_SIGNAL(src, COMSIG_MOB_RESET_PERSPECTIVE)
+	return TRUE
+
+/// Reapplies remote views based on object type and flags. Returns true if the view was assigned.
+/mob/proc/restore_remote_views()
+	if(!loc) // Nullspace during respawn
+		return FALSE
+	if(isturf(loc)) // Cannot be remote if it was a turf, also obj and turf flags overlap so stepping into space triggers remoteview endlessly.
+		return FALSE
+	// Check if we actually need to drop our current remote view component, as this is expensive to do, and leads to more difficult to understand error prone logic
+	var/datum/component/remote_view/remote_comp = GetComponent(/datum/component/remote_view)
+	if(remote_comp?.looking_at_target_already(loc))
+		return FALSE
+	if(isitem(loc) || isbelly(loc)) // Requires more careful handling than structures because they are held by mobs
+		AddComponent(/datum/component/remote_view/mob_holding_item, loc)
 		return TRUE
+	if(loc.flags & REMOTEVIEW_ON_ENTER) // Handle atoms that begin a remote view upon entering them.
+		AddComponent(/datum/component/remote_view, loc)
+		return TRUE
+	return FALSE
 
 /mob/proc/ret_grab(list/L, flag)
 	return
@@ -509,17 +559,17 @@
 	var/mob/mob_eye = targets[eye_name]
 
 	if(client && mob_eye)
-		client.eye = mob_eye
-		if (is_admin)
-			client.adminobs = 1
-			if(mob_eye == client.mob || client.eye == client.mob)
-				client.adminobs = 0
+		AddComponent(/datum/component/remote_view, focused_on = mob_eye)
+		if(is_admin)
+			client.adminobs = TRUE
+			if(mob_eye == client.mob || !is_remote_viewing())
+				client.adminobs = FALSE
 
 /mob/verb/cancel_camera()
 	set name = "Cancel Camera View"
 	set category = "OOC.Game"
 	unset_machine()
-	reset_view(null)
+	reset_perspective()
 
 /mob/Topic(href, href_list)
 	if(href_list["mach_close"])