gamemode decorators

code/controllers/subsystem/decorator.dm

@@ -29,7 +29,7 @@ SUBSYSTEM_DEF(decorator)
 	var/list/datum/weakref/currentrun = list()
 
 /datum/controller/subsystem/decorator/Initialize()
-	var/list/all_decors = typesof(/datum/decorator) - list(/datum/decorator) - typesof(/datum/decorator/manual)
+	var/list/all_decors = typesof(/datum/decorator) - list(/datum/decorator) - typesof(/datum/decorator/manual) - typesof(/datum/decorator/gamemode)
 	for(var/decor_type in all_decors)
 		var/datum/decorator/decor = new decor_type()
 		if(!decor.is_active_decor())
@@ -43,6 +43,8 @@ SUBSYSTEM_DEF(decorator)
 				registered_decorators[app_type] = list()
 			registered_decorators[app_type] += decor
 
+	RegisterSignal(SSdcs, COMSIG_GLOB_MODE_PRESETUP, PROC_REF(handle_mode_specific))
+
 	for(var/i in registered_decorators)
 		registered_decorators[i] = sortDecorators(registered_decorators[i])
 
@@ -71,6 +73,22 @@ SUBSYSTEM_DEF(decorator)
 		if(MC_TICK_CHECK)
 			return
 
+/datum/controller/subsystem/decorator/proc/handle_mode_specific()
+	for(var/decorator_type in typesof(/datum/decorator/gamemode))
+		var/datum/decorator/gamemode/gamemode_decorator = new decorator_type()
+
+		if(!istype(SSticker.mode, gamemode_decorator.gamemode))
+			continue
+
+		var/applicable_types = gamemode_decorator.get_decor_types()
+		if(!length(applicable_types))
+			continue
+
+		active_decorators |= gamemode_decorator
+
+		for(var/applicable_type in applicable_types)
+			LAZYADD(registered_decorators[applicable_type], gamemode_decorator)
+
 /datum/controller/subsystem/decorator/proc/add_decorator(decor_type, ...)
 	var/list/arguments = list()
 	if (length(args) > 1)

code/datums/decorators/gamemode_decorator.dm

@@ -0,0 +1,46 @@
+#define GAMEMODE_DECORATOR(type, mode, list_edits) \
+/datum/decorator/gamemode/##type { \
+	gamemode = mode; \
+	apply_type = type; \
+	edits = list_edits; \
+}
+
+#define VARIABLE_EDIT(type, variable, value) nameof(type::variable) = value
+#define ARMOR_EDIT(variable, value) VARIABLE_EDIT(/obj/item/clothing/suit/storage/marine, variable, value)
+#define GUN_EDIT(variable, value) VARIABLE_EDIT(/obj/item/weapon/gun, variable, value)
+#define AMMO_EDIT(variable, value) VARIABLE_EDIT(/obj/item/ammo_magazine, variable, value)
+
+/**
+ * Gamemode decorators allow us to make changes to edits on specific gamemodes,
+ * to assist in balancing varied gameplay in different modes
+ *
+ * They can be manually defined, and procs overridden. Alternatively,
+ * using the GAMEMODE_DECORATOR define, you can quickly make a decorator for
+ * a specific type and subtypes.
+ *
+ * eg:
+ * ```
+ * GAMEMODE_DECORATOR(/obj/item/clothing/suit/storage/marine/smartgunner, /datum/game_mode/extended/faction_clash, list(
+ *   ARMOR_EDIT(armor_bullet, CLOTHING_ARMOR_HIGH),
+ *   ARMOR_EDIT(armor_internaldamage, CLOTHING_ARMOR_HIGH)
+ *   ))
+ * ```
+ *
+ * If you need to edit different types, make a new define using VARIABLE_EDIT, and provide the parent path for the type.
+ */
+/datum/decorator/gamemode
+	/// The gamemode type this should apply to
+	var/gamemode
+
+	/// Which type this should apply edits to
+	var/apply_type
+
+	/// The list of edits to make
+	var/list/edits
+
+/datum/decorator/gamemode/get_decor_types()
+	return typesof(apply_type)
+
+/datum/decorator/gamemode/decorate(atom/object)
+	for(var/edit in edits)
+		object.vars[edit] = edits[edit]

colonialmarines.dme

@@ -431,6 +431,7 @@
 #include "code\datums\construction\construction_template.dm"
 #include "code\datums\construction\xenomorph\construction_template_xenomorph.dm"
 #include "code\datums\decorators\decorator.dm"
+#include "code\datums\decorators\gamemode_decorator.dm"
 #include "code\datums\diseases\addiction.dm"
 #include "code\datums\diseases\beesease.dm"
 #include "code\datums\diseases\black_goo.dm"