Adds Wheelchairs with basic driving functionality

code/game/objects/structures/stool_bed_chair_nest/wheelchair.dm

@@ -0,0 +1,107 @@
+/obj/structure/stool/bed/chair/wheelchair
+	name = "wheelchair"
+	desc = "You sit in this. Either by will or force."
+	icon_state = "wheelchair"
+	anchored = 0
+
+	var/driving = 0
+	var/mob/living/pulling = null
+
+
+/obj/structure/stool/bed/chair/wheelchair/handle_rotation()
+	overlays = null
+	var/image/O = image(icon = 'icons/obj/objects.dmi', icon_state = "w_overlay", layer = FLY_LAYER, dir = src.dir)
+	overlays += O
+	if(buckled_mob)
+		buckled_mob.dir = dir
+
+/obj/structure/stool/bed/chair/wheelchair/relaymove(mob/user, direction)
+	if(user.stat || user.stunned || user.weakened || user.paralysis || user.lying || user.restrained())
+		if(user==pulling)
+			pulling = null
+			user.pulledby = null
+			user << "\red You lost your grip!"
+	else if(user.pulling)
+		pulling = null
+		user.pulledby = null
+	else if(pulling && (get_dist(src, pulling) > 1))
+		pulling = null
+		user.pulledby = null
+	else if(pulling && (get_dir(src.loc, pulling.loc) == direction))
+		user << "\red You cannot go there."
+	else if(pulling && buckled_mob && (buckled_mob == user))
+		user << "\red You cannot drive while being pushed."
+	else
+		// Let's roll
+		driving = 1
+		var/turf/T = null
+		//--1---Move occupant---1--//
+		if(buckled_mob)
+			buckled_mob.buckled = null
+			step(buckled_mob, direction)
+			buckled_mob.buckled = src
+		//--2----Move driver----2--//
+		if(pulling)
+			T = pulling.loc
+			if(get_dist(src, pulling) >= 1)
+				step(pulling, get_dir(pulling.loc, src.loc))
+		//--3--Move wheelchair--3--//
+		step(src, direction)
+		if(buckled_mob) // Make sure it stays beneath the occupant
+			Move(buckled_mob.loc)
+		dir = direction
+		handle_rotation()
+		if(pulling) // Driver
+			if(pulling.loc == src.loc) // We moved onto the wheelchair? Revert!
+				pulling.loc = T
+			else
+				spawn(0)
+				pulling.dir = get_dir(pulling, src) // When everything is right, face the wheelchair
+		driving = 0
+
+/obj/structure/stool/bed/chair/wheelchair/Move()
+	..()
+	if(!driving && buckled_mob)
+		buckled_mob.buckled = null
+		buckled_mob.Move(src.loc)
+		buckled_mob.buckled = src
+		if (buckled_mob && (src.loc != buckled_mob.loc))
+			unbuckle()
+	handle_rotation()
+
+/obj/structure/stool/bed/chair/wheelchair/attack_hand(mob/user as mob)
+	if (pulling && (pulling == usr))
+		MouseDrop(usr)
+	else
+		manual_unbuckle(user)
+	return
+
+/obj/structure/stool/bed/chair/wheelchair/MouseDrop(over_object, src_location, over_location)
+	..()
+	if(over_object == usr && in_range(src, usr))
+		if(!ishuman(usr))	return
+		if(usr == buckled_mob)
+			usr << "\red You realize you are unable to push the wheelchair you sit in."
+			return
+		if(!pulling)
+			pulling = usr
+			usr.pulledby = src
+			if(usr.pulling)
+				usr.stop_pulling()
+			usr.dir = get_dir(usr, src)
+			usr << "You grip \the [name]'s handles."
+		else
+			if(usr != pulling)
+				for(var/mob/O in viewers(pulling, null))
+					O.show_message("\red [usr] breaks [pulling]'s grip on the wheelchair.", 1)
+			else
+				usr << "You let go of \the [name]'s handles."
+			pulling.pulledby = null
+			pulling = null
+		return
+
+/obj/structure/stool/bed/chair/wheelchair/buckle_mob(mob/M as mob, mob/user as mob)
+	if(M == pulling)
+		pulling = null
+		usr.pulledby = null
+	..()