Allows mult-shuttles to use docking controllers and adds docking to the merc shuttle

code/modules/shuttles/shuttles_multi.dm

@@ -14,19 +14,45 @@
 
 	var/area/interim
 	var/area/last_departed
+	var/start_location
+	var/last_location
 	var/list/destinations
+	var/list/destination_dock_controller_tags = list() //optional, in case the shuttle has multiple docking ports like the ERT shuttle (even though that isn't a multi_shuttle)
+	var/list/destination_dock_controllers = list()
+	var/list/destination_dock_targets = list()
 	var/area/origin
 	var/return_warning = 0
 
 /datum/shuttle/multi_shuttle/New()
 	..()
+
+/datum/shuttle/multi_shuttle/init_docking_controllers()
+	..()
+	for(var/destination in destinations)
+		var/controller_tag = destination_dock_controller_tags[destination]
+		if(!controller_tag)
+			destination_dock_controllers[destination] = docking_controller
+		else
+			var/datum/computer/file/embedded_program/docking/C = locate(controller_tag)
+			
+			if(!istype(C))
+				world << "<span class='danger'>warning: shuttle with docking tag [controller_tag] could not find it's controller!</span>"
+			else
+				destination_dock_controllers[destination] = C
+	
+	//might as well set this up here.
 	if(origin) last_departed = origin
+	last_location = start_location
+
+/datum/shuttle/multi_shuttle/current_dock_target()
+	return destination_dock_targets[last_location]
 
 /datum/shuttle/multi_shuttle/move(var/area/origin, var/area/destination)
 	..()
 	last_move = world.time
 	if (destination == src.origin)
 		returned_home = 1
+	docking_controller = destination_dock_controllers[last_location]
 
 /datum/shuttle/multi_shuttle/proc/announce_departure()
 
@@ -73,9 +99,53 @@
 	dat += "<br><b><A href='?src=\ref[src];toggle_cloak=[1]'>Toggle cloaking field</A></b><br>"
 	dat += "<b><A href='?src=\ref[src];move_multi=[1]'>Move ship</A></b><br>"
 	dat += "<b><A href='?src=\ref[src];start=[1]'>Return to base</A></b></center>"
+	
+	//Docking
+	dat += "<center><br><br>"
+	if(MS.skip_docking_checks())
+		dat += "Docking Status: <font color='grey'>Not in use.</font></center>"
+	else
+		var/override_en = MS.docking_controller.override_enabled
+		var/docking_status = MS.docking_controller.get_docking_status()
+		
+		dat += "Docking Status: "
+		switch(docking_status)
+			if("undocked")
+				dat += "<font color='[override_en? "red" : "grey"]'>Undocked</font>"
+			if("docking")
+				dat += "<font color='[override_en? "red" : "amber"]'>Docking</font>"
+			if("undocking")
+				dat += "<font color='[override_en? "red" : "amber"]'>Undocking</font>"
+			if("docked")
+				dat += "<font color='[override_en? "red" : "green"]'>Docked</font>"
+		
+		if(override_en) dat += " <font color='red'>(Override Enabled)</font>"
+		
+		dat += ".<br>"
+		
+		switch(docking_status)
+			if("undocked")
+				dat += "<b><A href='?src=\ref[src];dock_command=[1]'>Dock</A></b></center>"
+			if("docked")
+				dat += "<b><A href='?src=\ref[src];undock_command=[1]'>Undock</A></b></center>"
 
 	user << browse("[dat]", "window=[shuttle_tag]shuttlecontrol;size=300x600")
 
+//check if we're undocked, give option to force launch
+/obj/machinery/computer/shuttle_control/proc/check_docking(datum/shuttle/multi_shuttle/MS)
+	if(MS.skip_docking_checks() || MS.docking_controller.can_launch())
+		return 1
+
+	var/choice = alert("The shuttle is currently docked! Please undock before continuing.","Error","Cancel","Force Launch")
+	if(choice == "Cancel")
+		return 0
+			
+	choice = alert("Forcing a shuttle launch while docked may result in severe injury, death and/or damage to property. Are you sure you wish to continue?", "Force Launch", "Force Launch", "Cancel")
+	if(choice == "Cancel")
+		return 0
+	
+	return 1
+
 /obj/machinery/computer/shuttle_control/multi/Topic(href, href_list)
 	if(..())
 		return 1
@@ -91,13 +161,28 @@
 	if (MS.moving_status != SHUTTLE_IDLE)
 		usr << "\blue [shuttle_tag] vessel is moving."
 		return
+	
+	if(href_list["dock_command"])
+		MS.dock()
+		return
+	
+	if(href_list["undock_command"])
+		MS.undock()
+		return
 
 	if(href_list["start"])
-
 		if(MS.at_origin)
 			usr << "\red You are already at your home base."
 			return
+	
+		if((MS.last_move + MS.cooldown*10) > world.time)
+			usr << "\red The ship's drive is inoperable while the engines are charging."
+			return
 
+		if(!check_docking(MS))
+			updateUsrDialog()
+			return
+		
 		if(!MS.return_warning)
 			usr << "\red Returning to your home base will end your mission. If you are sure, press the button again."
 			//TODO: Actually end the mission.
@@ -106,6 +191,7 @@
 
 		MS.long_jump(MS.last_departed,MS.origin,MS.interim,MS.move_time)
 		MS.last_departed = MS.origin
+		MS.last_location = MS.start_location
 		MS.at_origin = 1
 
 	if(href_list["toggle_cloak"])
@@ -117,7 +203,11 @@
 		if((MS.last_move + MS.cooldown*10) > world.time)
 			usr << "\red The ship's drive is inoperable while the engines are charging."
 			return
-
+		
+		if(!check_docking(MS))
+			updateUsrDialog()
+			return
+		
 		var/choice = input("Select a destination.") as null|anything in MS.destinations
 		if(!choice) return
 
@@ -131,6 +221,7 @@
 
 			MS.long_jump(MS.last_departed, MS.destinations[choice], MS.interim, MS.move_time)
 			MS.last_departed = MS.destinations[choice]
+			MS.last_location = choice
 			return
 
 		else if(choice == MS.origin)
@@ -139,5 +230,6 @@
 
 		MS.short_jump(MS.last_departed, MS.destinations[choice])
 		MS.last_departed = MS.destinations[choice]
+		MS.last_location = choice
 
 	updateUsrDialog()