Genericises multi-dock prevention (#2358)

## About The Pull Request

Expands docking ticket functionality to include validation based on if
another docking ticket has been created for a specific port, hopefully
preventing multiple ships attempting to dock at the same port
simultaneously.

Also a freebie of ensuring planets which are generating can't be
interacted with and caused to load a second time, since that's icky.

## Why It's Good For The Game

Bugs from multiple people docking to an overmap object at once are bad.

## Changelog

:cl:
add: There's a few more descriptive docking errors now.
/:cl:

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code/controllers/subsystem/overmap.dm

@@ -262,7 +262,7 @@ SUBSYSTEM_DEF(overmap)
 	var/datum/map_template/ruin/used_ruin = ispath(ruin_type) ? (new ruin_type) : ruin_type
 
 	// name is random but PROBABLY unique
-	var/encounter_name = dynamic_datum.planet_name || "Dynamic Overmap Encounter #[rand(1111,9999)]-[rand(1111,9999)]"
+	var/encounter_name = dynamic_datum.planet_name || "\improper Uncharted Space [dynamic_datum.x]/[dynamic_datum.y]-[rand(1111, 9999)]"
 	var/datum/map_zone/mapzone = SSmapping.create_map_zone(encounter_name)
 	var/datum/virtual_level/vlevel = SSmapping.create_virtual_level(
 		encounter_name,
@@ -318,7 +318,7 @@ SUBSYSTEM_DEF(overmap)
 
 	var/obj/docking_port/stationary/primary_dock = new(primary_docking_turf)
 	primary_dock.dir = NORTH
-	primary_dock.name = "\improper Uncharted Space"
+	primary_dock.name = "[encounter_name] docking location #1"
 	primary_dock.height = RESERVE_DOCK_MAX_SIZE_SHORT
 	primary_dock.width = RESERVE_DOCK_MAX_SIZE_LONG
 	primary_dock.dheight = 0
@@ -327,7 +327,7 @@ SUBSYSTEM_DEF(overmap)
 
 	var/obj/docking_port/stationary/secondary_dock = new(secondary_docking_turf)
 	secondary_dock.dir = NORTH
-	secondary_dock.name = "\improper Uncharted Space"
+	secondary_dock.name = "[encounter_name] docking location #2"
 	secondary_dock.height = RESERVE_DOCK_MAX_SIZE_SHORT
 	secondary_dock.width = RESERVE_DOCK_MAX_SIZE_LONG
 	secondary_dock.dheight = 0
@@ -350,7 +350,7 @@ SUBSYSTEM_DEF(overmap)
 
 		var/obj/docking_port/stationary/tertiary_dock = new(tertiary_docking_turf)
 		tertiary_dock.dir = NORTH
-		tertiary_dock.name = "\improper Uncharted Space"
+		tertiary_dock.name = "[encounter_name] docking location #3"
 		tertiary_dock.height = RESERVE_DOCK_MAX_SIZE_SHORT
 		tertiary_dock.width = RESERVE_DOCK_MAX_SIZE_LONG
 		tertiary_dock.dheight = 0
@@ -359,7 +359,7 @@ SUBSYSTEM_DEF(overmap)
 
 		var/obj/docking_port/stationary/quaternary_dock = new(quaternary_docking_turf)
 		quaternary_dock.dir = NORTH
-		quaternary_dock.name = "\improper Uncharted Space"
+		quaternary_dock.name = "[encounter_name] docking location #4"
 		quaternary_dock.height = RESERVE_DOCK_MAX_SIZE_SHORT
 		quaternary_dock.width = RESERVE_DOCK_MAX_SIZE_LONG
 		quaternary_dock.dheight = 0

code/modules/overmap/_overmap_datum.dm

@@ -38,6 +38,9 @@
 	/// The icon state the token will be set to on init.
 	var/token_icon_state = "object"
 
+	/// The current docking ticket of this object, if any
+	var/datum/docking_ticket/current_docking_ticket
+
 /datum/overmap/New(position, ...)
 	SHOULD_NOT_OVERRIDE(TRUE) // Use [/datum/overmap/proc/Initialize] instead.
 	if(!position)
@@ -64,6 +67,8 @@
 
 /datum/overmap/Destroy(force, ...)
 	SSovermap.overmap_objects -= src
+	if(current_docking_ticket)
+		QDEL_NULL(current_docking_ticket)
 	if(docked_to)
 		docked_to.post_undocked()
 		docked_to.contents -= src
@@ -219,17 +224,20 @@
 	if(docked_to)
 		CRASH("Overmap datum [src] tried to dock to [docked_to] when it is already docked to another overmap datum.")
 
-	if(docking)
-		return
+	if(docking || current_docking_ticket)
+		return "Already docking!"
 	docking = TRUE
 
 	var/datum/docking_ticket/ticket = dock_target.pre_docked(src)
-	if(!ticket || ticket.docking_error)
+	var/ticket_error = ticket?.docking_error
+	if(!ticket || ticket_error)
+		qdel(ticket)
 		docking = FALSE
-		return ticket?.docking_error || "Unknown docking error!"
+		return ticket_error || "Unknown docking error!"
 	if(!pre_dock(dock_target, ticket))
+		qdel(ticket)
 		docking = FALSE
-		return
+		return ticket_error
 
 	start_dock(dock_target, ticket)
 
@@ -289,6 +297,9 @@
 	dock_target.post_docked(src)
 	docking = FALSE
 
+	//Clears the docking ticket from both sides
+	qdel(current_docking_ticket)
+
 	SEND_SIGNAL(src, COMSIG_OVERMAP_DOCK, dock_target)
 
 /**

code/modules/overmap/docking_ticket.dm

@@ -9,7 +9,40 @@
 	var/docking_error
 
 /datum/docking_ticket/New(_target_port, _issuer, _target, _docking_error)
+	docking_error = _docking_error
+	if(docking_error)
+		return
+
+	if(!_target_port)
+		docking_error = "No target port specified!"
+		return
 	target_port = _target_port
+	if(target_port.current_docking_ticket)
+		docking_error = "[target_port] is already being docked to!"
+		return
+	target_port.current_docking_ticket = src
+
+	if(!_issuer)
+		docking_error = "No issuer overmap datum specified!"
+		return
 	issuer = _issuer
+
+	if(!_target)
+		docking_error = "No target overmap datum specified!"
+		return
 	target = _target
-	docking_error = _docking_error
+	if(target.current_docking_ticket)
+		docking_error = "[target] is already docking!"
+		return
+	target.current_docking_ticket = src
+
+
+/datum/docking_ticket/Destroy(force, ...)
+	if(target)
+		target.current_docking_ticket = null
+		target = null
+	if(target_port)
+		target_port.current_docking_ticket = null
+		target_port = null
+
+	return ..()

code/modules/overmap/objects/dynamic_datum.dm

@@ -27,6 +27,8 @@
 	var/ruin_type
 	/// list of ruins and their target turf, indexed by name
 	var/list/ruin_turfs
+	/// Whether or not the level is currently loading.
+	var/loading = FALSE
 
 	/// The mapgenerator itself. SHOULD NOT BE NULL if the datum ever creates an encounter
 	var/datum/map_generator/mapgen = /datum/map_generator/single_turf/space
@@ -68,6 +70,8 @@
 		return get_turf(pick(reserve_docks))
 
 /datum/overmap/dynamic/pre_docked(datum/overmap/ship/controlled/dock_requester)
+	if(loading)
+		return new /datum/docking_ticket(_docking_error = "[src] is currently being scanned for suitable docking locations by another ship. Please wait.")
 	if(!load_level())
 		return new /datum/docking_ticket(_docking_error = "[src] cannot be docked to.")
 	else
@@ -177,15 +181,21 @@
 		return FALSE
 	if(mapzone)
 		return TRUE
+
+	loading = TRUE
 	log_shuttle("[src] [REF(src)] LEVEL_INIT")
+
 	// use the ruin type in template if it exists, or pick from ruin list if IT exists; otherwise null
 	var/selected_ruin = template || (ruin_type ? pickweightAllowZero(SSmapping.ruin_types_probabilities[ruin_type]) : null)
 	var/list/dynamic_encounter_values = SSovermap.spawn_dynamic_encounter(src, selected_ruin)
 	if(!length(dynamic_encounter_values))
 		return FALSE
+
 	mapzone = dynamic_encounter_values[1]
 	reserve_docks = dynamic_encounter_values[2]
 	ruin_turfs = dynamic_encounter_values[3]
+
+	loading = FALSE
 	return TRUE
 
 /datum/overmap/dynamic/empty

code/modules/overmap/objects/outpost/outpost.dm

@@ -33,9 +33,6 @@
 	/// The mapzone used by the outpost level and hangars. Using a single mapzone means networked radio messages.
 	var/datum/map_zone/mapzone
 	var/list/datum/hangar_shaft/shaft_datums = list()
-	/// A list keeping track of the docks that're currently being landed at. Helps to prevent SGTs,
-	/// as at time of writing there's no protection against a ship docking with a port that's already being docked to.
-	var/list/landing_in_progress_docks = list() // TODO: generalize this approach to prevent simultaneous-dock ship-overlap SGTs
 
 	/// The maximum number of missions that may be offered by the outpost at one time.
 	/// Missions which have been accepted do not count against this limit.
@@ -214,14 +211,10 @@
 		)
 		return FALSE
 
-	landing_in_progress_docks += h_dock
 	adjust_dock_to_shuttle(h_dock, dock_requester.shuttle_port)
 	return new /datum/docking_ticket(h_dock, src, dock_requester)
 
 /datum/overmap/outpost/post_docked(datum/overmap/ship/controlled/dock_requester)
-	// removes the stationary dock from the list, so that we don't have to worry about it causing merge SGTs
-	landing_in_progress_docks -= dock_requester.shuttle_port.docked
-
 	for(var/mob/M as anything in GLOB.player_list)
 		if(dock_requester.shuttle_port.is_in_shuttle_bounds(M))
 			M.play_screen_text("<span class='maptext' style=font-size:24pt;text-align:center valign='top'><u>[name]</u></span><br>[station_time_timestamp_fancy("hh:mm")]")
@@ -288,7 +281,7 @@
 			// a dock/undock cycle may leave the stationary port w/ flipped width and height,
 			// due to adjust_dock_to_shuttle(). so we need to check both orderings of the list.
 			if( \
-				!(h_dock in landing_in_progress_docks) && !h_dock.docked && \
+				!h_dock.current_docking_ticket && !h_dock.docked && \
 				( \
 					(h_dock.width == h_template.dock_width && h_dock.height == h_template.dock_height) || \
 					(h_dock.width == h_template.dock_height && h_dock.height == h_template.dock_width) \

code/modules/overmap/ships/controlled_ship_datum.dm

@@ -139,8 +139,10 @@
 
 /datum/overmap/ship/controlled/pre_dock(datum/overmap/to_dock, datum/docking_ticket/ticket)
 	if(ticket.target != src || ticket.issuer != to_dock)
+		ticket.docking_error = "Invalid target."
 		return FALSE
 	if(!shuttle_port.check_dock(ticket.target_port))
+		ticket.docking_error = "Targeted docking port invalid."
 		return FALSE
 	return TRUE
 

code/modules/shuttle/shuttle.dm

@@ -211,6 +211,8 @@
 	var/json_key
 	//Setting this to false will prevent the roundstart_template from being loaded on Initiallize(). You should set this to false if this loads a subship on a ship map template
 	var/load_template_on_initialize = TRUE
+	/// The docking ticket of the ship docking to this port.
+	var/datum/docking_ticket/current_docking_ticket
 
 /obj/docking_port/stationary/Initialize(mapload)
 	. = ..()