Refactors throwing (#25946)

* refactors datum/thrownthing

* cleanup

* lewc review

* calling parent doesn't do anything lmao

code/controllers/subsystem/SSthrowing.dm

@@ -42,15 +42,15 @@ SUBSYSTEM_DEF(throwing)
 
 	while(length(currentrun))
 		var/atom/movable/AM = currentrun[length(currentrun)]
-		var/datum/thrownthing/TT = currentrun[AM]
+		var/datum/thrownthing/thrown_thing = currentrun[AM]
 		currentrun.len--
-		if(!AM || !TT)
+		if(QDELETED(AM) || QDELETED(thrown_thing))
 			processing -= AM
 			if(MC_TICK_CHECK)
 				return
 			continue
 
-		TT.tick()
+		thrown_thing.tick()
 
 		if(MC_TICK_CHECK)
 			return
@@ -65,26 +65,51 @@ SUBSYSTEM_DEF(throwing)
 		skipped_sounds++
 
 /datum/thrownthing
+	///Thrown atom this datum is attached to
 	var/atom/movable/thrownthing
-	var/atom/target
+	///UID of the original intended target of the throw, to prevent hardDels
+	var/initial_target_uid
+	///The turf that the target was on, if it's not a turf itself.
 	var/turf/target_turf
+	///The turf that we were thrown from.
+	var/turf/starting_turf
+	///If the target happens to be a carbon and that carbon has a body zone aimed at, this is carried on here.
+	var/target_zone
+	///The initial direction of the thrower of the thrownthing for building the trajectory of the throw.
 	var/init_dir
+	///The maximum number of turfs that the thrownthing will travel to reach it's target.
 	var/maxrange
+	///Turfs to travel per tick
 	var/speed
-	var/mob/thrower
+	///If a mob is the one who has thrown the object, then its UID is stored here. This can be null and must be null checked before trying to use it.
+	var/thrower_uid
+	///A variable that helps in describing objects thrown at an angle, if it should be moved diagonally first or last.
 	var/diagonals_first
-	var/dist_travelled = 0
-	var/start_time
-	var/dist_x
-	var/dist_y
-	var/dx
-	var/dy
-	var/force = MOVE_FORCE_DEFAULT
+	///Set to TRUE if the throw is exclusively diagonal (45 Degree angle throws for example)
 	var/pure_diagonal
+	///Tracks how far a thrownthing has traveled mid-throw for the purposes of maxrange
+	var/dist_travelled = 0
+	///The start_time obtained via world.time for the purposes of tiles moved/tick.
+	var/start_time
+	///Distance to travel in the X axis/direction.
+	var/dist_x
+	///Distance to travel in the y axis/direction.
+	var/dist_y
+	///The Horizontal direction we're traveling (EAST or WEST)
+	var/dx
+	///The VERTICAL direction we're traveling (NORTH or SOUTH)
+	var/dy
+	///The movement force provided to a given object in transit. More info on these in move_force.dm
+	var/force = MOVE_FORCE_DEFAULT
+	///How many tiles that need to be moved in order to travel to the target.
 	var/diagonal_error
+	///If a thrown thing has a callback, it can be invoked here within thrownthing.
 	var/datum/callback/callback
+	///Mainly exists for things that would freeze a thrown object in place, like a timestop'd tile. Or a Tractor Beam.
 	var/paused = FALSE
+	///How long an object has been paused for, to be added to the travel time.
 	var/delayed_time = 0
+	///The last world.time value stored when the thrownthing was moving.
 	var/last_move = 0
 	///When this variable is false, non dense mobs will be hit by a thrown item. useful for things that you dont want to be cheesed by crawling, EG. gravitational anomalies
 	var/dodgeable = TRUE
@@ -93,6 +118,47 @@ SUBSYSTEM_DEF(throwing)
 	/// Will thrownthing datum actually block movement? this might be FALSE with some circumstances even if var/should_block_movement is TRUE. This variable change automatically during the throw
 	var/block_movement = TRUE
 
+/datum/thrownthing/New(thrownthing, atom/target, init_dir, maxrange, speed, atom/thrower, diagonals_first, force, callback, dodgeable, block_movement, target_zone)
+	src.thrownthing = thrownthing
+	RegisterSignal(thrownthing, COMSIG_PARENT_QDELETING, PROC_REF(on_thrownthing_qdel))
+	src.starting_turf = get_turf(thrownthing)
+	src.target_turf = get_turf(target)
+	if(target_turf != target)
+		src.initial_target_uid = target.UID()
+	src.init_dir = init_dir
+	src.maxrange = maxrange
+	src.speed = speed
+	if(thrower)
+		src.thrower_uid = thrower.UID()
+	src.diagonals_first = diagonals_first
+	src.force = force
+	src.callback = callback
+	src.dodgeable = dodgeable
+	src.should_block_movement = block_movement
+	src.target_zone = target_zone
+
+/datum/thrownthing/Destroy()
+	SSthrowing.processing -= thrownthing
+	SSthrowing.currentrun -= thrownthing
+	thrownthing.throwing = null
+	thrownthing = null
+	thrower_uid = null
+	initial_target_uid = null
+	callback = null
+	return ..()
+
+///Defines the datum behavior on the thrownthing's qdeletion event.
+/datum/thrownthing/proc/on_thrownthing_qdel(atom/movable/source, force)
+	SIGNAL_HANDLER	// COMSIG_PARENT_QDELETING
+
+	qdel(src)
+
+/// Returns the mob thrower, or null
+/datum/thrownthing/proc/get_thrower()
+	. = locateUID(thrower_uid)
+	if(isnull(.))
+		thrower_uid = null
+
 /datum/thrownthing/proc/tick()
 	var/atom/movable/AM = thrownthing
 	if(!isturf(AM.loc) || !AM.throwing)
@@ -103,9 +169,20 @@ SUBSYSTEM_DEF(throwing)
 		delayed_time += world.time - last_move
 		return
 
-	if(dist_travelled && hitcheck()) //to catch sneaky things moving on our tile while we slept
-		finalize()
-		return
+	var/atom/movable/actual_target = locateUID(initial_target_uid)
+	var/mob/mob_thrower = get_thrower()
+
+	if(dist_travelled) //to catch sneaky things moving on our tile while we slept
+		for(var/atom/movable/obstacle as anything in get_turf(thrownthing))
+			if(obstacle == thrownthing || (obstacle == mob_thrower && !ismob(thrownthing)))
+				continue
+			if(ismob(obstacle) && (thrownthing.pass_flags & PASSMOB) && (obstacle != actual_target))
+				continue
+			if(obstacle.pass_flags_self & LETPASSTHROW)
+				continue
+			if(obstacle == actual_target || (obstacle.density && !(obstacle.flags & ON_BORDER) && !(obstacle in AM.buckled_mobs)))
+				finalize(TRUE, obstacle)
+				return
 
 	var/atom/step
 
@@ -121,16 +198,15 @@ SUBSYSTEM_DEF(throwing)
 		else
 			gravity = has_gravity(AM, AM.loc)
 
-		if(!gravity)
-			block_movement = FALSE // you should be able to move if there is no gravity, supports jetpack movement during throw
-		else
-			block_movement = should_block_movement
-
 		if((dist_travelled >= maxrange || AM.loc == target_turf) && gravity)
-			hitcheck() //Just to be sure
 			finalize()
 			return
 
+		if(gravity)
+			block_movement = should_block_movement
+		else
+			block_movement = FALSE	// you should be able to move if there is no gravity, supports jetpack movement during throw
+
 		if(dist_travelled <= max(dist_x, dist_y)) //if we haven't reached the target yet we home in on it, otherwise we use the initial direction
 			step = get_step(AM, get_dir(AM, target_turf))
 		else
@@ -145,51 +221,55 @@ SUBSYSTEM_DEF(throwing)
 			finalize()
 			return
 
-		AM.Move(step, get_dir(AM, step))
+		if(!AM.Move(step, get_dir(AM, step))) // we hit something during our move...
+			if(AM.throwing) // ...but finalize() wasn't called on Bump() because of a higher level definition that doesn't always call parent.
+				finalize()
+			return
 
 		dist_travelled++
 
+		if(actual_target && !(actual_target.pass_flags_self & LETPASSTHROW) && actual_target.loc == AM.loc) // we crossed a movable with no density (e.g. a mouse or APC) we intend to hit anyway.
+			finalize(TRUE, actual_target)
+			return
+
 		if(dist_travelled > MAX_THROWING_DIST)
 			finalize()
 			return
 
 /datum/thrownthing/proc/finalize(hit = FALSE, target = null)
-	set waitfor = 0
-	SSthrowing.processing -= thrownthing
+	set waitfor = FALSE
 	//done throwing, either because it hit something or it finished moving
+	if(!thrownthing)
+		return
 	thrownthing.throwing = null
 	if(!hit)
-		for(var/thing in get_turf(thrownthing)) //looking for our target on the turf we land on.
-			var/atom/A = thing
-			if(A == target)
-				hit = 1
-				thrownthing.throw_impact(A, src)
+		for(var/atom/movable/obstacle as anything in get_turf(thrownthing)) //looking for our target on the turf we land on.
+			if(obstacle == target)
+				hit = TRUE
+				thrownthing.throw_impact(obstacle, src)
+				if(QDELETED(thrownthing)) //throw_impact can delete things, such as glasses smashing
+					return //deletion should already be handled by on_thrownthing_qdel()
 				break
 		if(!hit)
 			thrownthing.throw_impact(get_turf(thrownthing), src)  // we haven't hit something yet and we still must, let's hit the ground.
+			if(QDELETED(thrownthing)) //throw_impact can delete things, such as glasses smashing
+				return //deletion should already be handled by on_thrownthing_qdel()
 			thrownthing.newtonian_move(init_dir)
 	else
 		thrownthing.newtonian_move(init_dir)
 
 	if(target)
-		thrownthing.throw_impact(target, src, speed)
+		thrownthing.throw_impact(target, src)
+		if(QDELETED(thrownthing)) //throw_impact can delete things, such as glasses smashing
+			return //deletion should already be handled by on_thrownthing_qdel()
 
 	if(callback)
 		callback.Invoke()
-	SEND_SIGNAL(thrownthing, COMSIG_MOVABLE_THROW_LANDED, src)
-	thrownthing.end_throw()
 
-/datum/thrownthing/proc/hit_atom(atom/A)
-	finalize(hit = TRUE, target = A)
+	if(thrownthing)
+		SEND_SIGNAL(thrownthing, COMSIG_MOVABLE_THROW_LANDED, src)
 
-/datum/thrownthing/proc/hitcheck()
-	for(var/thing in get_turf(thrownthing))
-		var/atom/movable/AM = thing
-		if(AM == thrownthing || AM == thrower)
-			continue
-		if((AM.density || isliving(AM) && !dodgeable && !HAS_TRAIT(AM, TRAIT_DODGE_ALL_OBJECTS)) && !(AM.pass_flags & LETPASSTHROW) && !(AM.flags & ON_BORDER))
-			finalize(hit = TRUE, target = AM)
-			return TRUE
+	qdel(src)
 
 #undef MAX_THROWING_DIST
 #undef MAX_TICKS_TO_MAKE_UP