S.P.L.U.R.T-Station-13/code/game/atoms_movement.dm

// File for movement procs for atom/movable


////////////////////////////////////////
// Here's where we rewrite how byond handles movement except slightly different
// To be removed on step_ conversion
// All this work to prevent a second bump
/atom/movable/Move(atom/newloc, direct=0, glide_size_override = 0)
	. = FALSE
	if(!newloc || newloc == loc)
		return

	if(!direct)
		direct = get_dir(src, newloc)
	setDir(direct)

	if(!loc.Exit(src, newloc))
		return

	if(!newloc.Enter(src, src.loc))
		return

	if (SEND_SIGNAL(src, COMSIG_MOVABLE_PRE_MOVE, newloc) & COMPONENT_MOVABLE_BLOCK_PRE_MOVE)
		return

	// Past this is the point of no return
	var/atom/oldloc = loc
	var/area/oldarea = get_area(oldloc)
	var/area/newarea = get_area(newloc)
	loc = newloc
	. = TRUE
	oldloc.Exited(src, newloc)
	if(oldarea != newarea)
		oldarea.Exited(src, newloc)

	for(var/i in oldloc)
		if(i == src) // Multi tile objects
			continue
		var/atom/movable/thing = i
		thing.Uncrossed(src)

	newloc.Entered(src, oldloc)
	if(oldarea != newarea)
		newarea.Entered(src, oldloc)

	for(var/i in loc)
		if(i == src) // Multi tile objects
			continue
		var/atom/movable/thing = i
		thing.Crossed(src)

/**
 * meant for movement with zero side effects. only use for objects that are supposed to move "invisibly" (like camera mobs or ghosts)
 * if you want something to move onto a tile with a beartrap or recycler or tripmine or mouse without that object knowing about it at all, use this
 * most of the time you want forceMove()
 */
/atom/movable/proc/abstract_move(atom/new_loc)
	var/atom/old_loc = loc
	// move_stacks++
	loc = new_loc
	Moved(old_loc)

/atom/movable/Move(atom/newloc, direct, glide_size_override = 0)
	var/atom/movable/pullee = pulling
	var/turf/T = loc
	if(!moving_from_pull)
		check_pulling()
	if(!loc || !newloc)
		return FALSE
	var/atom/oldloc = loc
	//Early override for some cases like diagonal movement
	if(glide_size_override)
		set_glide_size(glide_size_override, FALSE)

	if(loc != newloc)
		if (!(direct & (direct - 1))) //Cardinal move
			. = ..()
		else //Diagonal move, split it into cardinal moves
			moving_diagonally = FIRST_DIAG_STEP
			var/first_step_dir
			// The `&& moving_diagonally` checks are so that a forceMove taking
			// place due to a Crossed, Bumped, etc. call will interrupt
			// the second half of the diagonal movement, or the second attempt
			// at a first half if step() fails because we hit something.
			if (direct & NORTH)
				if (direct & EAST)
					if (step(src, NORTH) && moving_diagonally)
						first_step_dir = NORTH
						moving_diagonally = SECOND_DIAG_STEP
						. = step(src, EAST)
					else if (moving_diagonally && step(src, EAST))
						first_step_dir = EAST
						moving_diagonally = SECOND_DIAG_STEP
						. = step(src, NORTH)
				else if (direct & WEST)
					if (step(src, NORTH) && moving_diagonally)
						first_step_dir = NORTH
						moving_diagonally = SECOND_DIAG_STEP
						. = step(src, WEST)
					else if (moving_diagonally && step(src, WEST))
						first_step_dir = WEST
						moving_diagonally = SECOND_DIAG_STEP
						. = step(src, NORTH)
			else if (direct & SOUTH)
				if (direct & EAST)
					if (step(src, SOUTH) && moving_diagonally)
						first_step_dir = SOUTH
						moving_diagonally = SECOND_DIAG_STEP
						. = step(src, EAST)
					else if (moving_diagonally && step(src, EAST))
						first_step_dir = EAST
						moving_diagonally = SECOND_DIAG_STEP
						. = step(src, SOUTH)
				else if (direct & WEST)
					if (step(src, SOUTH) && moving_diagonally)
						first_step_dir = SOUTH
						moving_diagonally = SECOND_DIAG_STEP
						. = step(src, WEST)
					else if (moving_diagonally && step(src, WEST))
						first_step_dir = WEST
						moving_diagonally = SECOND_DIAG_STEP
						. = step(src, SOUTH)
			if(moving_diagonally == SECOND_DIAG_STEP)
				if(!.)
					setDir(first_step_dir)
				else if (!inertia_moving)
					inertia_next_move = world.time + inertia_move_delay
					newtonian_move(direct)
			moving_diagonally = 0
			return

	if(!loc || (loc == oldloc && oldloc != newloc))
		last_move = 0
		return

	setDir(direct)
	if(.)
		Moved(oldloc, direct)
	if(. && pulling && pulling == pullee && pulling != moving_from_pull) //we were pulling a thing and didn't lose it during our move.
		if(pulling.anchored)
			stop_pulling()
		else
			var/pull_dir = get_dir(src, pulling)
			//puller and pullee more than one tile away or in diagonal position
			if(get_dist(src, pulling) > 1 || (moving_diagonally != SECOND_DIAG_STEP && ((pull_dir - 1) & pull_dir)))
				pulling.moving_from_pull = src
				pulling.Move(T, get_dir(pulling, T), glide_size) //the pullee tries to reach our previous position
				pulling.moving_from_pull = null
			check_pulling()


	//glide_size strangely enough can change mid movement animation and update correctly while the animation is playing
	//This means that if you don't override it late like this, it will just be set back by the movement update that's called when you move turfs.
	if(glide_size_override)
		set_glide_size(glide_size_override, FALSE)

	last_move = direct
	if(. && has_buckled_mobs() && !handle_buckled_mob_movement(loc, direct, glide_size_override)) //movement failed due to buckled mob(s)
		return FALSE

/atom/movable/proc/handle_buckled_mob_movement(newloc, direct, glide_size_override)
	for(var/m in buckled_mobs)
		var/mob/living/buckled_mob = m
		if(!buckled_mob.Move(newloc, direct, glide_size_override))
			forceMove(buckled_mob.loc)
			last_move = buckled_mob.last_move
			inertia_dir = last_move
			buckled_mob.inertia_dir = last_move
			return FALSE
	return TRUE

//Called after a successful Move(). By this point, we've already moved
/atom/movable/proc/Moved(atom/OldLoc, Dir, Forced = FALSE)
	SHOULD_CALL_PARENT(TRUE)
	SEND_SIGNAL(src, COMSIG_MOVABLE_MOVED, OldLoc, Dir, Forced)
	if (!inertia_moving)
		inertia_next_move = world.time + inertia_move_delay
		newtonian_move(Dir)
	return TRUE

// Make sure you know what you're doing if you call this, this is intended to only be called by byond directly.
// You probably want CanPass()
/atom/movable/Cross(atom/movable/AM)
	. = TRUE
	SEND_SIGNAL(src, COMSIG_MOVABLE_CROSS, AM)
	return CanPass(AM, AM.loc, TRUE)

//oldloc = old location on atom, inserted when forceMove is called and ONLY when forceMove is called!
/atom/movable/Crossed(atom/movable/AM, oldloc)
	// SHOULD_CALL_PARENT(TRUE)
	. = ..()
	SEND_SIGNAL(src, COMSIG_MOVABLE_CROSSED, AM)

/atom/movable/Uncross(atom/movable/AM, atom/newloc)
	. = ..()
	if(SEND_SIGNAL(src, COMSIG_MOVABLE_UNCROSS, AM) & COMPONENT_MOVABLE_BLOCK_UNCROSS)
		return FALSE
	if(isturf(newloc) && !CheckExit(AM, newloc))
		return FALSE

/atom/movable/Uncrossed(atom/movable/AM)
	SEND_SIGNAL(src, COMSIG_MOVABLE_UNCROSSED, AM)

/atom/movable/Bump(atom/A)
	if(!A)
		CRASH("Bump was called with no argument.")
	SEND_SIGNAL(src, COMSIG_MOVABLE_BUMP, A)
	. = ..()
	if(!QDELETED(throwing))
		throwing.finalize(hit = TRUE, target = A)
		. = TRUE
		if(QDELETED(A))
			return
	A.Bumped(src)

/atom/movable/proc/onTransitZ(old_z,new_z)
	SEND_SIGNAL(src, COMSIG_MOVABLE_Z_CHANGED, old_z, new_z)
	for (var/item in src) // Notify contents of Z-transition. This can be overridden IF we know the items contents do not care.
		var/atom/movable/AM = item
		AM.onTransitZ(old_z,new_z)

///Proc to modify the movement_type and hook behavior associated with it changing.
/atom/movable/proc/setMovetype(newval)
	if(movement_type == newval)
		return
	. = movement_type
	movement_type = newval

///////////// FORCED MOVEMENT /////////////

/atom/movable/proc/forceMove(atom/destination)
	. = FALSE
	if(destination)
		. = doMove(destination)
	else
		CRASH("No valid destination passed into forceMove")

/atom/movable/proc/moveToNullspace()
	return doMove(null)

/atom/movable/proc/doMove(atom/destination)
	. = FALSE
	if(destination)
		if(pulledby)
			pulledby.stop_pulling()
		var/atom/oldloc = loc
		var/same_loc = oldloc == destination
		var/area/old_area = get_area(oldloc)
		var/area/destarea = get_area(destination)

		loc = destination
		moving_diagonally = 0

		if(!same_loc)
			if(oldloc)
				oldloc.Exited(src, destination)
				if(old_area && old_area != destarea)
					old_area.Exited(src, destination)
			for(var/atom/movable/AM in oldloc)
				AM.Uncrossed(src)
			var/turf/oldturf = get_turf(oldloc)
			var/turf/destturf = get_turf(destination)
			var/old_z = (oldturf ? oldturf.z : null)
			var/dest_z = (destturf ? destturf.z : null)
			if (old_z != dest_z)
				onTransitZ(old_z, dest_z)
			destination.Entered(src, oldloc)
			if(destarea && old_area != destarea)
				destarea.Entered(src, oldloc)

			for(var/atom/movable/AM in destination)
				if(AM == src)
					continue
				AM.Crossed(src, oldloc)

		Moved(oldloc, NONE, TRUE)
		. = TRUE

	//If no destination, move the atom into nullspace (don't do this unless you know what you're doing)
	else
		. = TRUE
		if (loc)
			var/atom/oldloc = loc
			var/area/old_area = get_area(oldloc)
			oldloc.Exited(src, null)
			if(old_area)
				old_area.Exited(src, null)
		loc = null

/**
 * Called whenever an object moves and by mobs when they attempt to move themselves through space
 * And when an object or action applies a force on src, see [newtonian_move][/atom/movable/proc/newtonian_move]
 *
 * return FALSE to have src start/keep drifting in a no-grav area and 1 to stop/not start drifting
 *
 * Mobs should return TRUE if they should be able to move of their own volition, see [/client/proc/Move]
 *
 * Arguments:
 * * movement_dir - 0 when stopping or any dir when trying to move
 */
/atom/movable/proc/Process_Spacemove(movement_dir = 0)
	if(has_gravity(src))
		return TRUE

	if(pulledby && (pulledby.pulledby != src || moving_from_pull))
		return TRUE

	if(throwing)
		return TRUE

	if(!isturf(loc))
		return TRUE

	if(locate(/obj/structure/lattice) in range(1, get_turf(src))) //Not realistic but makes pushing things in space easier
		return TRUE

	return FALSE

/// Only moves the object if it's under no gravity
/atom/movable/proc/newtonian_move(direction)
	if(!isturf(loc) || Process_Spacemove(0))
		inertia_dir = 0
		return FALSE

	inertia_dir = direction
	if(!direction)
		return TRUE
	inertia_last_loc = loc
	SSspacedrift.processing[src] = src
	return TRUE