From b1ce79784d1dfe4502e6e1a1637465558db15f19 Mon Sep 17 00:00:00 2001
From: king5327 <king5327@users.noreply.github.com>
Date: Wed, 26 Apr 2023 18:57:40 -0400
Subject: [PATCH 1/6] Adds TGS tweaks.

---
 code/game/world.dm                  | 1 +
 code/modules/client/client_procs.dm | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/code/game/world.dm b/code/game/world.dm
index 475a6f76c5a..809185f2a66 100644
--- a/code/game/world.dm
+++ b/code/game/world.dm
@@ -166,6 +166,7 @@ var/world_topic_spam_protect_ip = "0.0.0.0"
 var/world_topic_spam_protect_time = world.timeofday
 
 /world/Topic(T, addr, master, key)
+	TGS_TOPIC
 	var/list/topic_handlers = WorldTopicHandlers()
 
 	var/list/input = params2list(T)
diff --git a/code/modules/client/client_procs.dm b/code/modules/client/client_procs.dm
index b3d3af59dfd..7889a44743e 100755
--- a/code/modules/client/client_procs.dm
+++ b/code/modules/client/client_procs.dm
@@ -249,6 +249,7 @@ GLOBAL_LIST_INIT(blacklisted_builds, list(
 
 
 	. = ..() //calls mob.Login()
+	++global.client_count
 	if (byond_version >= 512)
 		if (!byond_build || byond_build < 1386)
 			message_admins(span_adminnotice("[key_name(src)] has been detected as spoofing their byond version. Connection rejected."))
@@ -330,7 +331,8 @@ GLOBAL_LIST_INIT(blacklisted_builds, list(
 /client/Del()
 	if(!gc_destroyed)
 		Destroy() //Clean up signals and timers.
-	return ..()
+	. = ..()
+	--global.client_count
 
 /client/Destroy()
 	clients -= src

From 84eac10e04cd8d33ac0ef2ff040a77ce80850f16 Mon Sep 17 00:00:00 2001
From: king5327 <king5327@users.noreply.github.com>
Date: Wed, 26 Apr 2023 19:03:30 -0400
Subject: [PATCH 2/6] Update misc.dm

---
 code/_global_vars/misc.dm | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/code/_global_vars/misc.dm b/code/_global_vars/misc.dm
index c93128c3c28..297c1b33076 100644
--- a/code/_global_vars/misc.dm
+++ b/code/_global_vars/misc.dm
@@ -33,3 +33,6 @@ GLOBAL_PROTECT(log_directory)
 
 // TGUI MOVE ME //
 GLOBAL_DATUM(changelog_tgui, /datum/changelog)
+
+// TGS //
+GLOBAL_REAL_VAR(client_count)

From a07c7e3caf9e005a331ff310843f1b84bdc44c2d Mon Sep 17 00:00:00 2001
From: king5327 <king5327@users.noreply.github.com>
Date: Wed, 26 Apr 2023 19:31:59 -0400
Subject: [PATCH 3/6] Update world.dm

---
 code/game/world.dm | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/code/game/world.dm b/code/game/world.dm
index 809185f2a66..0491d945ccb 100644
--- a/code/game/world.dm
+++ b/code/game/world.dm
@@ -12,6 +12,8 @@ var/global/datum/global_init/init = new ()
 	Pre-map initialization stuff should go here.
 */
 
+#define TGS_TOPIC var/tgs_topic_return = TgsTopic(args[1]); if(tgs_topic_return) return tgs_topic_return
+
 /datum/global_init/New()
 	generate_gameid()
 	load_configuration()

From d879269a7e04785454d1134f0968b99b373223ab Mon Sep 17 00:00:00 2001
From: k5 <kfive@kfive.ca>
Date: Sat, 29 Apr 2023 01:46:38 -0400
Subject: [PATCH 4/6] Updates TGS, adds temporary restart announcer.

---
 code/controllers/master.dm            |   2 +
 tgs_dmapi/tgs.dm                      | 119 +++++++++++-
 tgs_dmapi/tgs/core/datum.dm           |   2 +
 tgs_dmapi/tgs/includes.dm             |   4 +
 tgs_dmapi/tgs/v3210/api.dm            |   9 +-
 tgs_dmapi/tgs/v3210/commands.dm       |  10 +-
 tgs_dmapi/tgs/v4/api.dm               |  15 +-
 tgs_dmapi/tgs/v4/commands.dm          |  11 +-
 tgs_dmapi/tgs/v5/README.md            |   5 +
 tgs_dmapi/tgs/v5/__interop_version.dm |   1 +
 tgs_dmapi/tgs/v5/_defines.dm          |  18 +-
 tgs_dmapi/tgs/v5/api.dm               | 195 ++++---------------
 tgs_dmapi/tgs/v5/bridge.dm            |  95 ++++++++++
 tgs_dmapi/tgs/v5/chunking.dm          |  43 +++++
 tgs_dmapi/tgs/v5/commands.dm          |  38 +++-
 tgs_dmapi/tgs/v5/serializers.dm       |  59 ++++++
 tgs_dmapi/tgs/v5/topic.dm             | 258 ++++++++++++++++++++++++++
 tgs_dmapi/tgs/v5/undefs.dm            |  16 +-
 18 files changed, 703 insertions(+), 197 deletions(-)
 create mode 100644 tgs_dmapi/tgs/v5/__interop_version.dm
 create mode 100644 tgs_dmapi/tgs/v5/bridge.dm
 create mode 100644 tgs_dmapi/tgs/v5/chunking.dm
 create mode 100644 tgs_dmapi/tgs/v5/serializers.dm
 create mode 100644 tgs_dmapi/tgs/v5/topic.dm

diff --git a/code/controllers/master.dm b/code/controllers/master.dm
index b895ad2b6ce..0278f8cb2f5 100755
--- a/code/controllers/master.dm
+++ b/code/controllers/master.dm
@@ -228,6 +228,8 @@ GLOBAL_REAL(Master, /datum/controller/master) = new
 
 	world.TgsInitializationComplete()
 
+	world.TgsTargetedChatBroadcast(new /datum/tgs_message_content{text = "A new round has begun!"})
+
 	// Sort subsystems by display setting for easy access.
 	sortTim(subsystems, /proc/cmp_subsystem_display)
 	// Set world options.
diff --git a/tgs_dmapi/tgs.dm b/tgs_dmapi/tgs.dm
index c4e9ec0c09f..557c1578612 100644
--- a/tgs_dmapi/tgs.dm
+++ b/tgs_dmapi/tgs.dm
@@ -227,6 +227,8 @@
 	var/is_private_channel
 	/// Tag string associated with the channel in TGS
 	var/custom_tag
+	/// [TRUE]/[FALSE] if the channel supports embeds
+	var/embeds_supported
 
 // Represents a chat user
 /datum/tgs_chat_user
@@ -256,9 +258,11 @@
 	var/help_text = ""
 	/// If this command should be available to game administrators only
 	var/admin_only = FALSE
+	/// A subtype of [/datum/tgs_chat_command] that is ignored when enumerating available commands. Use this to create shared base /datums for commands.
+	var/ignore_type
 
 /**
- * Process command activation. Should return a string to respond to the issuer with.
+ * Process command activation. Should return a [/datum/tgs_message_content] to respond to the issuer with.
  *
  * sender - The [/datum/tgs_chat_user] who issued the command.
  * params - The trimmed string following the command `/datum/tgs_chat_command/var/name].
@@ -266,6 +270,107 @@
 /datum/tgs_chat_command/proc/Run(datum/tgs_chat_user/sender, params)
 	CRASH("[type] has no implementation for Run()")
 
+/// User definable chat message
+/datum/tgs_message_content
+	/// The tring content of the message. Must be provided in New().
+	var/text
+
+	/// The [/datum/tgs_chat_embed] to embed in the message. Not supported on all chat providers.
+	var/datum/tgs_chat_embed/structure/embed
+
+/datum/tgs_message_content/New(text)
+	if(!istext(text))
+		TGS_ERROR_LOG("[/datum/tgs_message_content] created with no text!")
+		text = null
+
+	src.text = text
+
+/// User definable chat embed. Currently mirrors Discord chat embeds. See https://discord.com/developers/docs/resources/channel#embed-object-embed-structure for details.
+/datum/tgs_chat_embed/structure
+	var/title
+	var/description
+	var/url
+
+	/// Timestamp must be encoded as: time2text(world.timeofday, "YYYY-MM-DD hh:mm:ss"). Use the active timezone.
+	var/timestamp
+
+	/// Colour must be #AARRGGBB or #RRGGBB hex string
+	var/colour
+
+	/// See https://discord.com/developers/docs/resources/channel#embed-object-embed-image-structure for details.
+	var/datum/tgs_chat_embed/media/image
+
+	/// See https://discord.com/developers/docs/resources/channel#embed-object-embed-thumbnail-structure for details.
+	var/datum/tgs_chat_embed/media/thumbnail
+
+	/// See https://discord.com/developers/docs/resources/channel#embed-object-embed-image-structure for details.
+	var/datum/tgs_chat_embed/media/video
+
+	var/datum/tgs_chat_embed/footer/footer
+	var/datum/tgs_chat_embed/provider/provider
+	var/datum/tgs_chat_embed/provider/author/author
+
+	var/list/datum/tgs_chat_embed/field/fields
+
+/// Common datum for similar discord embed medias
+/datum/tgs_chat_embed/media
+	/// Must be set in New().
+	var/url
+	var/width
+	var/height
+	var/proxy_url
+
+/datum/tgs_chat_embed/media/New(url)
+	if(!istext(url))
+		CRASH("[/datum/tgs_chat_embed/media] created with no url!")
+
+	src.url = url
+
+/// See https://discord.com/developers/docs/resources/channel#embed-object-embed-footer-structure for details.
+/datum/tgs_chat_embed/footer
+	/// Must be set in New().
+	var/text
+	var/icon_url
+	var/proxy_icon_url
+
+/datum/tgs_chat_embed/footer/New(text)
+	if(!istext(text))
+		CRASH("[/datum/tgs_chat_embed/footer] created with no text!")
+
+	src.text = text
+
+/// See https://discord.com/developers/docs/resources/channel#embed-object-embed-provider-structure for details.
+/datum/tgs_chat_embed/provider
+	var/name
+	var/url
+
+/// See https://discord.com/developers/docs/resources/channel#embed-object-embed-author-structure for details. Must have name set in New().
+/datum/tgs_chat_embed/provider/author
+	var/icon_url
+	var/proxy_icon_url
+
+/datum/tgs_chat_embed/provider/author/New(name)
+	if(!istext(name))
+		CRASH("[/datum/tgs_chat_embed/provider/author] created with no name!")
+
+	src.name = name
+
+/// See https://discord.com/developers/docs/resources/channel#embed-object-embed-field-structure for details. Must have name and value set in New().
+/datum/tgs_chat_embed/field
+	var/name
+	var/value
+	var/is_inline
+
+/datum/tgs_chat_embed/field/New(name, value)
+	if(!istext(name))
+		CRASH("[/datum/tgs_chat_embed/field] created with no name!")
+
+	if(!istext(value))
+		CRASH("[/datum/tgs_chat_embed/field] created with no value!")
+
+	src.name = name
+	src.value = value
+
 // API FUNCTIONS
 
 /// Returns the maximum supported [/datum/tgs_version] of the DMAPI.
@@ -296,19 +401,19 @@
 /**
  * Send a message to connected chats.
  *
- * message - The string to send.
+ * message - The [/datum/tgs_message_content] to send.
  * admin_only: If [TRUE], message will be sent to admin connected chats. Vice-versa applies.
  */
-/world/proc/TgsTargetedChatBroadcast(message, admin_only = FALSE)
+/world/proc/TgsTargetedChatBroadcast(datum/tgs_message_content/message, admin_only = FALSE)
 	return
 
 /**
  * Send a private message to a specific user.
  *
- * message - The string to send.
+ * message - The [/datum/tgs_message_content] to send.
  * user: The [/datum/tgs_chat_user] to PM.
  */
-/world/proc/TgsChatPrivateMessage(message, datum/tgs_chat_user/user)
+/world/proc/TgsChatPrivateMessage(datum/tgs_message_content/message, datum/tgs_chat_user/user)
 	return
 
 // The following functions will sleep if a call to TgsNew() is sleeping
@@ -316,10 +421,10 @@
 /**
  * Send a message to connected chats that are flagged as game-related in TGS.
  *
- * message - The string to send.
+ * message - The [/datum/tgs_message_content] to send.
  * channels - Optional list of [/datum/tgs_chat_channel]s to restrict the message to.
  */
-/world/proc/TgsChatBroadcast(message, list/channels = null)
+/world/proc/TgsChatBroadcast(datum/tgs_message_content/message, list/channels = null)
 	return
 
 /// Returns the current [/datum/tgs_version] of TGS if it is running the server, null otherwise.
diff --git a/tgs_dmapi/tgs/core/datum.dm b/tgs_dmapi/tgs/core/datum.dm
index 4d37ed662d1..68b0330fe86 100644
--- a/tgs_dmapi/tgs/core/datum.dm
+++ b/tgs_dmapi/tgs/core/datum.dm
@@ -4,6 +4,8 @@ TGS_DEFINE_AND_SET_GLOBAL(tgs, null)
 	var/datum/tgs_version/version
 	var/datum/tgs_event_handler/event_handler
 
+	var/list/warned_deprecated_command_runs
+
 /datum/tgs_api/New(datum/tgs_event_handler/event_handler, datum/tgs_version/version)
 	. = ..()
 	src.event_handler = event_handler
diff --git a/tgs_dmapi/tgs/includes.dm b/tgs_dmapi/tgs/includes.dm
index 4018074f4e3..23b714f9d06 100644
--- a/tgs_dmapi/tgs/includes.dm
+++ b/tgs_dmapi/tgs/includes.dm
@@ -13,5 +13,9 @@
 
 #include "v5\_defines.dm"
 #include "v5\api.dm"
+#include "v5\bridge.dm"
+#include "v5\chunking.dm"
 #include "v5\commands.dm"
+#include "v5\serializers.dm"
+#include "v5\topic.dm"
 #include "v5\undefs.dm"
diff --git a/tgs_dmapi/tgs/v3210/api.dm b/tgs_dmapi/tgs/v3210/api.dm
index 3c218d5b10b..b881662d71c 100644
--- a/tgs_dmapi/tgs/v3210/api.dm
+++ b/tgs_dmapi/tgs/v3210/api.dm
@@ -193,16 +193,19 @@
 /datum/tgs_api/v3210/ChatChannelInfo()
 	return list() // :omegalul:
 
-/datum/tgs_api/v3210/ChatBroadcast(message, list/channels)
+/datum/tgs_api/v3210/ChatBroadcast(datum/tgs_message_content/message, list/channels)
 	if(channels)
 		return TGS_UNIMPLEMENTED
+	message = UpgradeDeprecatedChatMessage(message)
 	ChatTargetedBroadcast(message, TRUE)
 	ChatTargetedBroadcast(message, FALSE)
 
-/datum/tgs_api/v3210/ChatTargetedBroadcast(message, admin_only)
-	ExportService("[admin_only ? SERVICE_REQUEST_IRC_ADMIN_CHANNEL_MESSAGE : SERVICE_REQUEST_IRC_BROADCAST] [message]")
+/datum/tgs_api/v3210/ChatTargetedBroadcast(datum/tgs_message_content/message, admin_only)
+	message = UpgradeDeprecatedChatMessage(message)
+	ExportService("[admin_only ? SERVICE_REQUEST_IRC_ADMIN_CHANNEL_MESSAGE : SERVICE_REQUEST_IRC_BROADCAST] [message.text]")
 
 /datum/tgs_api/v3210/ChatPrivateMessage(message, datum/tgs_chat_user/user)
+	UpgradeDeprecatedChatMessage(message)
 	return TGS_UNIMPLEMENTED
 
 /datum/tgs_api/v3210/SecurityLevel()
diff --git a/tgs_dmapi/tgs/v3210/commands.dm b/tgs_dmapi/tgs/v3210/commands.dm
index 4ccfc1a8a60..d9bd287465b 100644
--- a/tgs_dmapi/tgs/v3210/commands.dm
+++ b/tgs_dmapi/tgs/v3210/commands.dm
@@ -10,9 +10,12 @@
 	var/warned_about_the_dangers_of_robutussin = !warnings_only
 	for(var/I in typesof(/datum/tgs_chat_command) - /datum/tgs_chat_command)
 		if(!warned_about_the_dangers_of_robutussin)
-			TGS_ERROR_LOG("Custom chat commands in [ApiVersion()] lacks the /datum/tgs_chat_user/sender.channel field!")
+			TGS_WARNING_LOG("Custom chat commands in [ApiVersion()] lacks the /datum/tgs_chat_user/sender.channel field!")
 			warned_about_the_dangers_of_robutussin = TRUE
 		var/datum/tgs_chat_command/stc = I
+		if(stc.ignore_type == I)
+			continue
+
 		var/command_name = initial(stc.name)
 		if(!command_name || findtext(command_name, " ") || findtext(command_name, "'") || findtext(command_name, "\""))
 			if(warnings_only && !warned_command_names[command_name])
@@ -49,4 +52,7 @@
 		sender = "<@[sender]>"
 
 	user.mention = sender
-	return stc.Run(user, params) || TRUE
+	var/datum/tgs_message_content/result = stc.Run(user, params)
+	result = UpgradeDeprecatedCommandResponse(result, command)
+
+	return result?.text || TRUE
diff --git a/tgs_dmapi/tgs/v4/api.dm b/tgs_dmapi/tgs/v4/api.dm
index 0e37a7aa24c..2f05c386338 100644
--- a/tgs_dmapi/tgs/v4/api.dm
+++ b/tgs_dmapi/tgs/v4/api.dm
@@ -256,33 +256,36 @@
 /datum/tgs_api/v4/Revision()
 	return cached_revision
 
-/datum/tgs_api/v4/ChatBroadcast(message, list/channels)
+/datum/tgs_api/v4/ChatBroadcast(datum/tgs_message_content/message, list/channels)
 	var/list/ids
 	if(length(channels))
 		ids = list()
 		for(var/I in channels)
 			var/datum/tgs_chat_channel/channel = I
 			ids += channel.id
-	message = list("message" = message, "channelIds" = ids)
+	message = UpgradeDeprecatedChatMessage(message)
+	message = list("message" = message.text, "channelIds" = ids)
 	if(intercepted_message_queue)
 		intercepted_message_queue += list(message)
 	else
 		Export(TGS4_COMM_CHAT, message)
 
-/datum/tgs_api/v4/ChatTargetedBroadcast(message, admin_only)
+/datum/tgs_api/v4/ChatTargetedBroadcast(datum/tgs_message_content/message, admin_only)
 	var/list/channels = list()
 	for(var/I in ChatChannelInfo())
 		var/datum/tgs_chat_channel/channel = I
 		if (!channel.is_private_channel && ((channel.is_admin_channel && admin_only) || (!channel.is_admin_channel && !admin_only)))
 			channels += channel.id
-	message = list("message" = message, "channelIds" = channels)
+	message = UpgradeDeprecatedChatMessage(message)
+	message = list("message" = message.text, "channelIds" = channels)
 	if(intercepted_message_queue)
 		intercepted_message_queue += list(message)
 	else
 		Export(TGS4_COMM_CHAT, message)
 
-/datum/tgs_api/v4/ChatPrivateMessage(message, datum/tgs_chat_user/user)
-	message = list("message" = message, "channelIds" = list(user.channel.id))
+/datum/tgs_api/v4/ChatPrivateMessage(datum/tgs_message_content/message, datum/tgs_chat_user/user)
+	message = UpgradeDeprecatedChatMessage(message)
+	message = list("message" = message.text, "channelIds" = list(user.channel.id))
 	if(intercepted_message_queue)
 		intercepted_message_queue += list(message)
 	else
diff --git a/tgs_dmapi/tgs/v4/commands.dm b/tgs_dmapi/tgs/v4/commands.dm
index 4ca1500167b..d6d3d718d47 100644
--- a/tgs_dmapi/tgs/v4/commands.dm
+++ b/tgs_dmapi/tgs/v4/commands.dm
@@ -3,6 +3,9 @@
 	custom_commands = list()
 	for(var/I in typesof(/datum/tgs_chat_command) - /datum/tgs_chat_command)
 		var/datum/tgs_chat_command/stc = new I
+		if(stc.ignore_type == I)
+			continue
+
 		var/command_name = stc.name
 		if(!command_name || findtext(command_name, " ") || findtext(command_name, "'") || findtext(command_name, "\""))
 			TGS_ERROR_LOG("Custom command [command_name] ([I]) can't be used as it is empty or contains illegal characters!")
@@ -34,8 +37,8 @@
 
 	var/datum/tgs_chat_command/sc = custom_commands[command]
 	if(sc)
-		var/result = sc.Run(u, params)
-		if(result == null)
-			result = ""
-		return result
+		var/datum/tgs_message_content/result = sc.Run(u, params)
+		result = UpgradeDeprecatedCommandResponse(result, command)
+
+		return result?.text
 	return "Unknown command: [command]!"
diff --git a/tgs_dmapi/tgs/v5/README.md b/tgs_dmapi/tgs/v5/README.md
index 5b48d57a1f0..a8a0c748e7b 100644
--- a/tgs_dmapi/tgs/v5/README.md
+++ b/tgs_dmapi/tgs/v5/README.md
@@ -2,7 +2,12 @@
 
 This DMAPI implements bridge requests using HTTP GET requests to TGS. It has no security restrictions.
 
+- [__interop_version.dm](./__interop_version.dm) contains the version of the API used between the DMAPI and TGS.
 - [_defines.dm](./_defines.dm) contains constant definitions.
 - [api.dm](./api.dm) contains the bulk of the API code.
+- [bridge.dm](./bridge.dm) contains functions related to making bridge requests.
+- [chunking.dm](./chunking.dm) contains common function for splitting large raw data sets into chunks BYOND can natively process.
 - [commands.dm](./commands.dm) contains functions relating to `/datum/tgs_chat_command`s.
+- [serializers.dm](./serializers.dm) contains function to help convert interop `/datum`s into a JSON encodable `list()` format.
+- [topic.dm](./topic.dm) contains functions related to processing topic requests.
 - [undefs.dm](./undefs.dm) Undoes the work of `_defines.dm`.
diff --git a/tgs_dmapi/tgs/v5/__interop_version.dm b/tgs_dmapi/tgs/v5/__interop_version.dm
new file mode 100644
index 00000000000..6ef7c86ef75
--- /dev/null
+++ b/tgs_dmapi/tgs/v5/__interop_version.dm
@@ -0,0 +1 @@
+"5.6.0"
diff --git a/tgs_dmapi/tgs/v5/_defines.dm b/tgs_dmapi/tgs/v5/_defines.dm
index 10bc4cbe406..a3f949081f1 100644
--- a/tgs_dmapi/tgs/v5/_defines.dm
+++ b/tgs_dmapi/tgs/v5/_defines.dm
@@ -4,16 +4,29 @@
 #define DMAPI5_BRIDGE_DATA "data"
 #define DMAPI5_TOPIC_DATA "tgs_data"
 
+#define DMAPI5_BRIDGE_REQUEST_LIMIT 8198
+#define DMAPI5_TOPIC_REQUEST_LIMIT 65529
+#define DMAPI5_TOPIC_RESPONSE_LIMIT 65528
+
 #define DMAPI5_BRIDGE_COMMAND_PORT_UPDATE 0
 #define DMAPI5_BRIDGE_COMMAND_STARTUP 1
 #define DMAPI5_BRIDGE_COMMAND_PRIME 2
 #define DMAPI5_BRIDGE_COMMAND_REBOOT 3
 #define DMAPI5_BRIDGE_COMMAND_KILL 4
 #define DMAPI5_BRIDGE_COMMAND_CHAT_SEND 5
+#define DMAPI5_BRIDGE_COMMAND_CHUNK 6
 
 #define DMAPI5_PARAMETER_ACCESS_IDENTIFIER "accessIdentifier"
 #define DMAPI5_PARAMETER_CUSTOM_COMMANDS "customCommands"
 
+#define DMAPI5_CHUNK "chunk"
+#define DMAPI5_CHUNK_PAYLOAD "payload"
+#define DMAPI5_CHUNK_TOTAL "totalChunks"
+#define DMAPI5_CHUNK_SEQUENCE_ID "sequenceId"
+#define DMAPI5_CHUNK_PAYLOAD_ID "payloadId"
+
+#define DMAPI5_MISSING_CHUNKS "missingChunks"
+
 #define DMAPI5_RESPONSE_ERROR_MESSAGE "errorMessage"
 
 #define DMAPI5_BRIDGE_PARAMETER_COMMAND_TYPE "commandType"
@@ -25,7 +38,6 @@
 #define DMAPI5_BRIDGE_RESPONSE_NEW_PORT "newPort"
 #define DMAPI5_BRIDGE_RESPONSE_RUNTIME_INFORMATION "runtimeInformation"
 
-#define DMAPI5_CHAT_MESSAGE_TEXT "text"
 #define DMAPI5_CHAT_MESSAGE_CHANNEL_IDS "channelIds"
 
 #define DMAPI5_RUNTIME_INFORMATION_ACCESS_IDENTIFIER "accessIdentifier"
@@ -65,6 +77,8 @@
 #define DMAPI5_TOPIC_COMMAND_SERVER_PORT_UPDATE 6
 #define DMAPI5_TOPIC_COMMAND_HEARTBEAT 7
 #define DMAPI5_TOPIC_COMMAND_WATCHDOG_REATTACH 8
+#define DMAPI5_TOPIC_COMMAND_SEND_CHUNK 9
+#define DMAPI5_TOPIC_COMMAND_RECEIVE_CHUNK 10
 
 #define DMAPI5_TOPIC_PARAMETER_COMMAND_TYPE "commandType"
 #define DMAPI5_TOPIC_PARAMETER_CHAT_COMMAND "chatCommand"
@@ -75,6 +89,7 @@
 #define DMAPI5_TOPIC_PARAMETER_CHAT_UPDATE "chatUpdate"
 #define DMAPI5_TOPIC_PARAMETER_NEW_SERVER_VERSION "newServerVersion"
 
+#define DMAPI5_TOPIC_RESPONSE_COMMAND_RESPONSE "commandResponse"
 #define DMAPI5_TOPIC_RESPONSE_COMMAND_RESPONSE_MESSAGE "commandResponseMessage"
 #define DMAPI5_TOPIC_RESPONSE_CHAT_RESPONSES "chatResponses"
 
@@ -93,6 +108,7 @@
 #define DMAPI5_CHAT_CHANNEL_IS_ADMIN_CHANNEL "isAdminChannel"
 #define DMAPI5_CHAT_CHANNEL_IS_PRIVATE_CHANNEL "isPrivateChannel"
 #define DMAPI5_CHAT_CHANNEL_TAG "tag"
+#define DMAPI5_CHAT_CHANNEL_EMBEDS_SUPPORTED "embedsSupported"
 
 #define DMAPI5_CUSTOM_CHAT_COMMAND_NAME "name"
 #define DMAPI5_CUSTOM_CHAT_COMMAND_HELP_TEXT "helpText"
diff --git a/tgs_dmapi/tgs/v5/api.dm b/tgs_dmapi/tgs/v5/api.dm
index 572944ed401..517240f12f8 100644
--- a/tgs_dmapi/tgs/v5/api.dm
+++ b/tgs_dmapi/tgs/v5/api.dm
@@ -17,9 +17,14 @@
 
 	var/initialized = FALSE
 
+	var/chunked_requests = 0
+	var/list/chunked_topics = list()
+
+	var/detached = FALSE
+
 /datum/tgs_api/v5/ApiVersion()
 	return new /datum/tgs_version(
-		#include "interop_version.dm"
+		#include "__interop_version.dm"
 	)
 
 /datum/tgs_api/v5/OnWorldNew(minimum_required_security_level)
@@ -97,172 +102,18 @@
 /datum/tgs_api/v5/OnInitializationComplete()
 	Bridge(DMAPI5_BRIDGE_COMMAND_PRIME)
 
-/datum/tgs_api/v5/proc/TopicResponse(error_message = null)
-	var/list/response = list()
-	response[DMAPI5_RESPONSE_ERROR_MESSAGE] = error_message
-
-	return json_encode(response)
-
 /datum/tgs_api/v5/OnTopic(T)
+	RequireInitialBridgeResponse()
 	var/list/params = params2list(T)
 	var/json = params[DMAPI5_TOPIC_DATA]
 	if(!json)
 		return FALSE // continue to /world/Topic
 
-	var/list/topic_parameters = json_decode(json)
-	if(!topic_parameters)
-		return TopicResponse("Invalid topic parameters json!");
-
 	if(!initialized)
-		TGS_WARNING_LOG("Missed topic due to not being initialized: [T]")
+		TGS_WARNING_LOG("Missed topic due to not being initialized: [json]")
 		return TRUE // too early to handle, but it's still our responsibility
 
-	var/their_sCK = topic_parameters[DMAPI5_PARAMETER_ACCESS_IDENTIFIER]
-	if(their_sCK != access_identifier)
-		return TopicResponse("Failed to decode [DMAPI5_PARAMETER_ACCESS_IDENTIFIER] from: [json]!");
-
-	var/command = topic_parameters[DMAPI5_TOPIC_PARAMETER_COMMAND_TYPE]
-	if(!isnum(command))
-		return TopicResponse("Failed to decode [DMAPI5_TOPIC_PARAMETER_COMMAND_TYPE] from: [json]!")
-
-	switch(command)
-		if(DMAPI5_TOPIC_COMMAND_CHAT_COMMAND)
-			var/result = HandleCustomCommand(topic_parameters[DMAPI5_TOPIC_PARAMETER_CHAT_COMMAND])
-			if(!result)
-				result = TopicResponse("Error running chat command!")
-			return result
-		if(DMAPI5_TOPIC_COMMAND_EVENT_NOTIFICATION)
-			intercepted_message_queue = list()
-			var/list/event_notification = topic_parameters[DMAPI5_TOPIC_PARAMETER_EVENT_NOTIFICATION]
-			if(!istype(event_notification))
-				return TopicResponse("Invalid [DMAPI5_TOPIC_PARAMETER_EVENT_NOTIFICATION]!")
-
-			var/event_type = event_notification[DMAPI5_EVENT_NOTIFICATION_TYPE]
-			if(!isnum(event_type))
-				return TopicResponse("Invalid or missing [DMAPI5_EVENT_NOTIFICATION_TYPE]!")
-
-			var/list/event_parameters = event_notification[DMAPI5_EVENT_NOTIFICATION_PARAMETERS]
-			if(event_parameters && !istype(event_parameters))
-				return TopicResponse("Invalid or missing [DMAPI5_EVENT_NOTIFICATION_PARAMETERS]!")
-
-			var/list/event_call = list(event_type)
-			if(event_parameters)
-				event_call += event_parameters
-
-			if(event_handler != null)
-				event_handler.HandleEvent(arglist(event_call))
-
-			var/list/response = list()
-			response[DMAPI5_TOPIC_RESPONSE_CHAT_RESPONSES] = intercepted_message_queue
-			intercepted_message_queue = null
-			return json_encode(response)
-		if(DMAPI5_TOPIC_COMMAND_CHANGE_PORT)
-			var/new_port = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_PORT]
-			if (!isnum(new_port) || !(new_port > 0))
-				return TopicResponse("Invalid or missing [DMAPI5_TOPIC_PARAMETER_NEW_PORT]]")
-
-			if(event_handler != null)
-				event_handler.HandleEvent(TGS_EVENT_PORT_SWAP, new_port)
-
-			//the topic still completes, miraculously
-			//I honestly didn't believe byond could do it without exploding
-			if(!world.OpenPort(new_port))
-				return TopicResponse("Port change failed!")
-
-			return TopicResponse()
-		if(DMAPI5_TOPIC_COMMAND_CHANGE_REBOOT_STATE)
-			var/new_reboot_mode = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_REBOOT_STATE]
-			if(!isnum(new_reboot_mode))
-				return TopicResponse("Invalid or missing [DMAPI5_TOPIC_PARAMETER_NEW_REBOOT_STATE]!")
-
-			if(event_handler != null)
-				event_handler.HandleEvent(TGS_EVENT_REBOOT_MODE_CHANGE, reboot_mode, new_reboot_mode)
-
-			reboot_mode = new_reboot_mode
-			return TopicResponse()
-		if(DMAPI5_TOPIC_COMMAND_INSTANCE_RENAMED)
-			var/new_instance_name = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_INSTANCE_NAME]
-			if(!istext(new_instance_name))
-				return TopicResponse("Invalid or missing [DMAPI5_TOPIC_PARAMETER_NEW_INSTANCE_NAME]!")
-
-			if(event_handler != null)
-				event_handler.HandleEvent(TGS_EVENT_INSTANCE_RENAMED, new_instance_name)
-
-			instance_name = new_instance_name
-			return TopicResponse()
-		if(DMAPI5_TOPIC_COMMAND_CHAT_CHANNELS_UPDATE)
-			var/list/chat_update_json = topic_parameters[DMAPI5_TOPIC_PARAMETER_CHAT_UPDATE]
-			if(!istype(chat_update_json))
-				return TopicResponse("Invalid or missing [DMAPI5_TOPIC_PARAMETER_CHAT_UPDATE]!")
-
-			DecodeChannels(chat_update_json)
-			return TopicResponse()
-		if(DMAPI5_TOPIC_COMMAND_SERVER_PORT_UPDATE)
-			var/new_port = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_PORT]
-			if (!isnum(new_port) || !(new_port > 0))
-				return TopicResponse("Invalid or missing [DMAPI5_TOPIC_PARAMETER_NEW_PORT]]")
-
-			server_port = new_port
-			return TopicResponse()
-		if(DMAPI5_TOPIC_COMMAND_HEARTBEAT)
-			return TopicResponse()
-		if(DMAPI5_TOPIC_COMMAND_WATCHDOG_REATTACH)
-			var/new_port = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_PORT]
-			var/error_message = null
-			if (new_port != null)
-				if (!isnum(new_port) || !(new_port > 0))
-					error_message = "Invalid [DMAPI5_TOPIC_PARAMETER_NEW_PORT]]"
-				else
-					server_port = new_port
-
-			var/new_version_string = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_SERVER_VERSION]
-			if (!istext(new_version_string))
-				if(error_message != null)
-					error_message += ", "
-				error_message += "Invalid or missing [DMAPI5_TOPIC_PARAMETER_NEW_SERVER_VERSION]]"
-			else
-				var/datum/tgs_version/new_version = new(new_version_string)
-				if (event_handler)
-					event_handler.HandleEvent(TGS_EVENT_WATCHDOG_REATTACH, new_version)
-
-				version = new_version
-
-			return json_encode(list(DMAPI5_RESPONSE_ERROR_MESSAGE = error_message, DMAPI5_PARAMETER_CUSTOM_COMMANDS = ListCustomCommands()))
-
-	return TopicResponse("Unknown command: [command]")
-
-/datum/tgs_api/v5/proc/Bridge(command, list/data)
-	if(!data)
-		data = list()
-
-	data[DMAPI5_BRIDGE_PARAMETER_COMMAND_TYPE] = command
-	data[DMAPI5_PARAMETER_ACCESS_IDENTIFIER] = access_identifier
-
-	var/json = json_encode(data)
-	var/encoded_json = url_encode(json)
-
-	// This is an infinite sleep until we get a response
-	var/export_response = world.Export("http://127.0.0.1:[server_port]/Bridge?[DMAPI5_BRIDGE_DATA]=[encoded_json]")
-	if(!export_response)
-		TGS_ERROR_LOG("Failed export request: [json]")
-		return
-
-	var/response_json = file2text(export_response["CONTENT"])
-	if(!response_json)
-		TGS_ERROR_LOG("Failed export request, missing content!")
-		return
-
-	var/list/bridge_response = json_decode(response_json)
-	if(!bridge_response)
-		TGS_ERROR_LOG("Failed export request, bad json: [response_json]")
-		return
-
-	var/error = bridge_response[DMAPI5_RESPONSE_ERROR_MESSAGE]
-	if(error)
-		TGS_ERROR_LOG("Failed export request, bad request: [error]")
-		return
-
-	return bridge_response
+	return ProcessTopicJson(json, TRUE)
 
 /datum/tgs_api/v5/OnReboot()
 	var/list/result = Bridge(DMAPI5_BRIDGE_COMMAND_REBOOT)
@@ -297,7 +148,15 @@
 	RequireInitialBridgeResponse()
 	return revision
 
-/datum/tgs_api/v5/ChatBroadcast(message, list/channels)
+// Common proc b/c it's used by the V3/V4 APIs
+/datum/tgs_api/proc/UpgradeDeprecatedChatMessage(datum/tgs_message_content/message)
+	if(!istext(message))
+		return message
+
+	TGS_WARNING_LOG("Received legacy string when a [/datum/tgs_message_content] was expected. Please audit all calls to TgsChatBroadcast, TgsChatTargetedBroadcast, and TgsChatPrivateMessage to ensure they use the new /datum.")
+	return new /datum/tgs_message_content(message)
+
+/datum/tgs_api/v5/ChatBroadcast(datum/tgs_message_content/message, list/channels)
 	if(!length(channels))
 		channels = ChatChannelInfo()
 
@@ -306,26 +165,33 @@
 		var/datum/tgs_chat_channel/channel = I
 		ids += channel.id
 
-	message = list(DMAPI5_CHAT_MESSAGE_TEXT = message, DMAPI5_CHAT_MESSAGE_CHANNEL_IDS = ids)
+	message = UpgradeDeprecatedChatMessage(message)
+	message = message._interop_serialize()
+	message[DMAPI5_CHAT_MESSAGE_CHANNEL_IDS] = ids
 	if(intercepted_message_queue)
 		intercepted_message_queue += list(message)
 	else
 		Bridge(DMAPI5_BRIDGE_COMMAND_CHAT_SEND, list(DMAPI5_BRIDGE_PARAMETER_CHAT_MESSAGE = message))
 
-/datum/tgs_api/v5/ChatTargetedBroadcast(message, admin_only)
+/datum/tgs_api/v5/ChatTargetedBroadcast(datum/tgs_message_content/message, admin_only)
 	var/list/channels = list()
 	for(var/I in ChatChannelInfo())
 		var/datum/tgs_chat_channel/channel = I
 		if (!channel.is_private_channel && ((channel.is_admin_channel && admin_only) || (!channel.is_admin_channel && !admin_only)))
 			channels += channel.id
-	message = list(DMAPI5_CHAT_MESSAGE_TEXT = message, DMAPI5_CHAT_MESSAGE_CHANNEL_IDS = channels)
+
+	message = UpgradeDeprecatedChatMessage(message)
+	message = message._interop_serialize()
+	message[DMAPI5_CHAT_MESSAGE_CHANNEL_IDS] = channels
 	if(intercepted_message_queue)
 		intercepted_message_queue += list(message)
 	else
 		Bridge(DMAPI5_BRIDGE_COMMAND_CHAT_SEND, list(DMAPI5_BRIDGE_PARAMETER_CHAT_MESSAGE = message))
 
-/datum/tgs_api/v5/ChatPrivateMessage(message, datum/tgs_chat_user/user)
-	message = list(DMAPI5_CHAT_MESSAGE_TEXT = message, DMAPI5_CHAT_MESSAGE_CHANNEL_IDS = list(user.channel.id))
+/datum/tgs_api/v5/ChatPrivateMessage(datum/tgs_message_content/message, datum/tgs_chat_user/user)
+	message = UpgradeDeprecatedChatMessage(message)
+	message = message._interop_serialize()
+	message[DMAPI5_CHAT_MESSAGE_CHANNEL_IDS] = list(user.channel.id)
 	if(intercepted_message_queue)
 		intercepted_message_queue += list(message)
 	else
@@ -354,6 +220,7 @@
 	channel.is_admin_channel = channel_json[DMAPI5_CHAT_CHANNEL_IS_ADMIN_CHANNEL]
 	channel.is_private_channel = channel_json[DMAPI5_CHAT_CHANNEL_IS_PRIVATE_CHANNEL]
 	channel.custom_tag = channel_json[DMAPI5_CHAT_CHANNEL_TAG]
+	channel.embeds_supported = channel_json[DMAPI5_CHAT_CHANNEL_EMBEDS_SUPPORTED]
 	return channel
 
 /datum/tgs_api/v5/SecurityLevel()
diff --git a/tgs_dmapi/tgs/v5/bridge.dm b/tgs_dmapi/tgs/v5/bridge.dm
new file mode 100644
index 00000000000..b3cf7759397
--- /dev/null
+++ b/tgs_dmapi/tgs/v5/bridge.dm
@@ -0,0 +1,95 @@
+/datum/tgs_api/v5/proc/Bridge(command, list/data)
+	if(!data)
+		data = list()
+
+	var/single_bridge_request = CreateBridgeRequest(command, data)
+	if(length(single_bridge_request) <= DMAPI5_BRIDGE_REQUEST_LIMIT)
+		return PerformBridgeRequest(single_bridge_request)
+
+	// chunking required
+	var/payload_id = ++chunked_requests
+
+	var/raw_data = CreateBridgeData(command, data, FALSE)
+
+	var/list/chunk_requests = GenerateChunks(raw_data, TRUE)
+
+	var/list/response
+	for(var/bridge_request in chunk_requests)
+		response = PerformBridgeRequest(bridge_request)
+		if(!response)
+			// Abort
+			return
+
+	var/list/missing_sequence_ids = response[DMAPI5_MISSING_CHUNKS]
+	if(length(missing_sequence_ids))
+		do
+			TGS_WARNING_LOG("Server is still missing some chunks of bridge P[payload_id]! Sending missing chunks...")
+			if(!istype(missing_sequence_ids))
+				TGS_ERROR_LOG("Did not receive a list() for [DMAPI5_MISSING_CHUNKS]!")
+				return
+
+			for(var/missing_sequence_id in missing_sequence_ids)
+				if(!isnum(missing_sequence_id))
+					TGS_ERROR_LOG("Did not receive a num in [DMAPI5_MISSING_CHUNKS]!")
+					return
+
+				var/missing_chunk_request = chunk_requests[missing_sequence_id + 1]
+				response = PerformBridgeRequest(missing_chunk_request)
+				if(!response)
+					// Abort
+					return
+
+			missing_sequence_ids = response[DMAPI5_MISSING_CHUNKS]
+		while(length(missing_sequence_ids))
+
+	return response
+
+/datum/tgs_api/v5/proc/CreateBridgeRequest(command, list/data)
+	var/json = CreateBridgeData(command, data, TRUE)
+	var/encoded_json = url_encode(json)
+
+	var/url = "http://127.0.0.1:[server_port]/Bridge?[DMAPI5_BRIDGE_DATA]=[encoded_json]"
+	return url
+
+/datum/tgs_api/v5/proc/CreateBridgeData(command, list/data, needs_auth)
+	data[DMAPI5_BRIDGE_PARAMETER_COMMAND_TYPE] = command
+	if(needs_auth)
+		data[DMAPI5_PARAMETER_ACCESS_IDENTIFIER] = access_identifier
+
+	var/json = json_encode(data)
+	return json
+
+/datum/tgs_api/v5/proc/PerformBridgeRequest(bridge_request)
+	if(detached)
+		// Wait up to one minute
+		for(var/i in 1 to 600)
+			sleep(1)
+			if(!detached)
+				break
+
+			// dad went out for milk cigarettes 20 years ago...
+			if(i == 600)
+				detached = FALSE
+
+	// This is an infinite sleep until we get a response
+	var/export_response = world.Export(bridge_request)
+	if(!export_response)
+		TGS_ERROR_LOG("Failed bridge request: [bridge_request]")
+		return
+
+	var/response_json = file2text(export_response["CONTENT"])
+	if(!response_json)
+		TGS_ERROR_LOG("Failed bridge request, missing content!")
+		return
+
+	var/list/bridge_response = json_decode(response_json)
+	if(!bridge_response)
+		TGS_ERROR_LOG("Failed bridge request, bad json: [response_json]")
+		return
+
+	var/error = bridge_response[DMAPI5_RESPONSE_ERROR_MESSAGE]
+	if(error)
+		TGS_ERROR_LOG("Failed bridge request, bad request: [error]")
+		return
+
+	return bridge_response
diff --git a/tgs_dmapi/tgs/v5/chunking.dm b/tgs_dmapi/tgs/v5/chunking.dm
new file mode 100644
index 00000000000..cd5944d34fb
--- /dev/null
+++ b/tgs_dmapi/tgs/v5/chunking.dm
@@ -0,0 +1,43 @@
+/datum/tgs_api/v5/proc/GenerateChunks(payload, bridge)
+	var/limit = bridge ? DMAPI5_BRIDGE_REQUEST_LIMIT : DMAPI5_TOPIC_RESPONSE_LIMIT
+
+	var/payload_id = ++chunked_requests
+	var/data_length = length(payload)
+
+	var/chunk_count
+	var/list/chunk_requests
+	for(chunk_count = 2; !chunk_requests; ++chunk_count)
+		var/max_chunk_size = -round(-(data_length / chunk_count))
+		if(max_chunk_size > limit)
+			continue
+
+		chunk_requests = list()
+		for(var/i in 1 to chunk_count)
+			var/start_index = 1 + ((i - 1) * max_chunk_size)
+			if (start_index > data_length)
+				break
+
+			var/end_index = min(1 + (i * max_chunk_size), data_length + 1)
+
+			var/chunk_payload = copytext(payload, start_index, end_index)
+
+			// sequence IDs in interop chunking are always zero indexed
+			var/list/chunk = list(DMAPI5_CHUNK_PAYLOAD_ID = payload_id, DMAPI5_CHUNK_SEQUENCE_ID = (i - 1), DMAPI5_CHUNK_TOTAL = chunk_count, DMAPI5_CHUNK_PAYLOAD = chunk_payload)
+
+			var/chunk_request = list(DMAPI5_CHUNK = chunk)
+			var/chunk_length
+			if(bridge)
+				chunk_request = CreateBridgeRequest(DMAPI5_BRIDGE_COMMAND_CHUNK, chunk_request)
+				chunk_length = length(chunk_request)
+			else
+				chunk_request = list(chunk_request) // wrap for adding to list
+				chunk_length = length(json_encode(chunk_request))
+
+			if(chunk_length > limit)
+				// Screwed by encoding, no way to preempt it though
+				chunk_requests = null
+				break
+
+			chunk_requests += chunk_request
+
+	return chunk_requests
diff --git a/tgs_dmapi/tgs/v5/commands.dm b/tgs_dmapi/tgs/v5/commands.dm
index 6d31dd3422d..a832c81f172 100644
--- a/tgs_dmapi/tgs/v5/commands.dm
+++ b/tgs_dmapi/tgs/v5/commands.dm
@@ -3,14 +3,17 @@
 	custom_commands = list()
 	for(var/I in typesof(/datum/tgs_chat_command) - /datum/tgs_chat_command)
 		var/datum/tgs_chat_command/stc = new I
+		if(stc.ignore_type == I)
+			continue
+
 		var/command_name = stc.name
 		if(!command_name || findtext(command_name, " ") || findtext(command_name, "'") || findtext(command_name, "\""))
-			TGS_WARNING_LOG("Custom command [command_name] ([I]) can't be used as it is empty or contains illegal characters!")
+			TGS_ERROR_LOG("Custom command [command_name] ([I]) can't be used as it is empty or contains illegal characters!")
 			continue
 
 		if(results[command_name])
 			var/datum/other = custom_commands[command_name]
-			TGS_WARNING_LOG("Custom commands [other.type] and [I] have the same name (\"[command_name]\"), only [other.type] will be available!")
+			TGS_ERROR_LOG("Custom commands [other.type] and [I] have the same name (\"[command_name]\"), only [other.type] will be available!")
 			continue
 		results += list(list(DMAPI5_CUSTOM_CHAT_COMMAND_NAME = command_name, DMAPI5_CUSTOM_CHAT_COMMAND_HELP_TEXT = stc.help_text, DMAPI5_CUSTOM_CHAT_COMMAND_ADMIN_ONLY = stc.admin_only))
 		custom_commands[command_name] = stc
@@ -30,11 +33,28 @@
 
 	var/datum/tgs_chat_command/sc = custom_commands[command]
 	if(sc)
-		var/text_response = sc.Run(u, params)
-		var/list/topic_response = list()
-		if(!istext(text_response))
-			TGS_ERROR_LOG("Custom command [command] should return a string! Got: \"[text_response]\"")
-			text_response = null
-		topic_response[DMAPI5_TOPIC_RESPONSE_COMMAND_RESPONSE_MESSAGE] = text_response
-		return json_encode(topic_response)
+		var/datum/tgs_message_content/response = sc.Run(u, params)
+		response = UpgradeDeprecatedCommandResponse(response, command)
+		
+		var/list/topic_response = TopicResponse()
+		topic_response[DMAPI5_TOPIC_RESPONSE_COMMAND_RESPONSE_MESSAGE] = response?.text
+		topic_response[DMAPI5_TOPIC_RESPONSE_COMMAND_RESPONSE] = response?._interop_serialize()
+		return topic_response
 	return TopicResponse("Unknown custom chat command: [command]!")
+
+// Common proc b/c it's used by the V3/V4 APIs
+/datum/tgs_api/proc/UpgradeDeprecatedCommandResponse(datum/tgs_message_content/response, command)
+	// Backwards compatibility, used to return a string
+	if(istext(response))
+		warned_deprecated_command_runs = warned_deprecated_command_runs || list()
+		if(!warned_deprecated_command_runs[command])
+			TGS_WARNING_LOG("Custom chat command \"[command]\" is still returning a string. This behaviour is deprecated, please upgrade it to return a [/datum/tgs_message_content].")
+			warned_deprecated_command_runs[command] = TRUE
+
+		return new /datum/tgs_message_content(response)
+
+	if(!istype(response))
+		TGS_ERROR_LOG("Custom chat command \"[command]\" should return a [/datum/tgs_message_content]! Got: \"[response]\"")
+		return null
+
+	return response
diff --git a/tgs_dmapi/tgs/v5/serializers.dm b/tgs_dmapi/tgs/v5/serializers.dm
new file mode 100644
index 00000000000..7f9bc731b79
--- /dev/null
+++ b/tgs_dmapi/tgs/v5/serializers.dm
@@ -0,0 +1,59 @@
+/datum/tgs_message_content/proc/_interop_serialize()
+	return list("text" = text, "embed" = embed?._interop_serialize())
+
+/datum/tgs_chat_embed/proc/_interop_serialize()
+	CRASH("Base /proc/interop_serialize called on [type]!")
+
+/datum/tgs_chat_embed/structure/_interop_serialize()
+	var/list/serialized_fields
+	if(islist(fields))
+		serialized_fields = list()
+		for(var/datum/tgs_chat_embed/field/field as anything in fields)
+			serialized_fields += list(field._interop_serialize())
+	return list(
+		"title" = title,
+		"description" = description,
+		"url" = url,
+		"timestamp" = timestamp,
+		"colour" = colour,
+		"image" = image?._interop_serialize(),
+		"thumbnail" = thumbnail?._interop_serialize(),
+		"video" = video?._interop_serialize(),
+		"footer" = footer?._interop_serialize(),
+		"provider" = provider?._interop_serialize(),
+		"author" = author?._interop_serialize(),
+		"fields" = serialized_fields
+	)
+
+/datum/tgs_chat_embed/media/_interop_serialize()
+	return list(
+		"url" = url,
+		"width" = width,
+		"height" = height,
+		"proxyUrl" = proxy_url
+	)
+
+/datum/tgs_chat_embed/provider/_interop_serialize()
+	return list(
+		"url" = url,
+		"name" = name
+	)
+
+/datum/tgs_chat_embed/provider/author/_interop_serialize()
+	. = ..()
+	.["iconUrl"] = icon_url
+	.["proxyIconUrl"] = proxy_icon_url
+	
+/datum/tgs_chat_embed/footer/_interop_serialize()
+	return list(
+		"text" = text,
+		"iconUrl" = icon_url,
+		"proxyIconUrl" = proxy_icon_url
+	)
+
+/datum/tgs_chat_embed/field/_interop_serialize()
+	return list(
+		"name" = name,
+		"value" = value,
+		"isInline" = is_inline
+	)
diff --git a/tgs_dmapi/tgs/v5/topic.dm b/tgs_dmapi/tgs/v5/topic.dm
new file mode 100644
index 00000000000..28fcc14aef8
--- /dev/null
+++ b/tgs_dmapi/tgs/v5/topic.dm
@@ -0,0 +1,258 @@
+/datum/tgs_api/v5/proc/TopicResponse(error_message = null)
+	var/list/response = list()
+	if(error_message)
+		response[DMAPI5_RESPONSE_ERROR_MESSAGE] = error_message
+	return response
+
+/datum/tgs_api/v5/proc/ProcessTopicJson(json, check_access_identifier)
+	var/list/result = ProcessRawTopic(json, check_access_identifier)
+	if(!result)
+		result = TopicResponse("Runtime error!")
+	else if(!length(result))
+		return "{}" // quirk of json_encode is an empty list returns "[]"
+
+	var/response_json = json_encode(result)
+	if(length(response_json) > DMAPI5_TOPIC_RESPONSE_LIMIT)
+		// cache response chunks and send the first
+		var/list/chunks = GenerateChunks(response_json, FALSE)
+		var/payload_id = chunks[1][DMAPI5_CHUNK][DMAPI5_CHUNK_PAYLOAD_ID]
+		var/cache_key = ResponseTopicChunkCacheKey(payload_id)
+
+		chunked_topics[cache_key] = chunks
+
+		response_json = json_encode(chunks[1])
+
+	return response_json
+
+/datum/tgs_api/v5/proc/ProcessRawTopic(json, check_access_identifier)
+	var/list/topic_parameters = json_decode(json)
+	if(!topic_parameters)
+		return TopicResponse("Invalid topic parameters json: [json]!");
+
+	var/their_sCK = topic_parameters[DMAPI5_PARAMETER_ACCESS_IDENTIFIER]
+	if(check_access_identifier && their_sCK != access_identifier)
+		return TopicResponse("Failed to decode [DMAPI5_PARAMETER_ACCESS_IDENTIFIER]!")
+
+	var/command = topic_parameters[DMAPI5_TOPIC_PARAMETER_COMMAND_TYPE]
+	if(!isnum(command))
+		return TopicResponse("Failed to decode [DMAPI5_TOPIC_PARAMETER_COMMAND_TYPE]!")
+
+	return ProcessTopicCommand(command, topic_parameters)
+
+/datum/tgs_api/v5/proc/ResponseTopicChunkCacheKey(payload_id)
+	return "response[payload_id]"
+
+/datum/tgs_api/v5/proc/ProcessTopicCommand(command, list/topic_parameters)
+	switch(command)
+
+		if(DMAPI5_TOPIC_COMMAND_CHAT_COMMAND)
+			intercepted_message_queue = list()
+			var/list/result = HandleCustomCommand(topic_parameters[DMAPI5_TOPIC_PARAMETER_CHAT_COMMAND])
+			if(!result)
+				result = TopicResponse("Error running chat command!")
+			result[DMAPI5_TOPIC_RESPONSE_CHAT_RESPONSES] = intercepted_message_queue
+			intercepted_message_queue = null
+			return result
+
+		if(DMAPI5_TOPIC_COMMAND_EVENT_NOTIFICATION)
+			intercepted_message_queue = list()
+			var/list/event_notification = topic_parameters[DMAPI5_TOPIC_PARAMETER_EVENT_NOTIFICATION]
+			if(!istype(event_notification))
+				return TopicResponse("Invalid [DMAPI5_TOPIC_PARAMETER_EVENT_NOTIFICATION]!")
+
+			var/event_type = event_notification[DMAPI5_EVENT_NOTIFICATION_TYPE]
+			if(!isnum(event_type))
+				return TopicResponse("Invalid or missing [DMAPI5_EVENT_NOTIFICATION_TYPE]!")
+
+			var/list/event_parameters = event_notification[DMAPI5_EVENT_NOTIFICATION_PARAMETERS]
+			if(event_parameters && !istype(event_parameters))
+				return TopicResponse("Invalid or missing [DMAPI5_EVENT_NOTIFICATION_PARAMETERS]!")
+
+			var/list/event_call = list(event_type)
+			if (event_type == TGS_EVENT_WATCHDOG_DETACH)
+				detached = TRUE
+
+			if(event_parameters)
+				event_call += event_parameters
+
+			if(event_handler != null)
+				event_handler.HandleEvent(arglist(event_call))
+
+			var/list/response = TopicResponse()
+			response[DMAPI5_TOPIC_RESPONSE_CHAT_RESPONSES] = intercepted_message_queue
+			intercepted_message_queue = null
+			return response
+
+		if(DMAPI5_TOPIC_COMMAND_CHANGE_PORT)
+			var/new_port = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_PORT]
+			if (!isnum(new_port) || !(new_port > 0))
+				return TopicResponse("Invalid or missing [DMAPI5_TOPIC_PARAMETER_NEW_PORT]]")
+
+			if(event_handler != null)
+				event_handler.HandleEvent(TGS_EVENT_PORT_SWAP, new_port)
+
+			//the topic still completes, miraculously
+			//I honestly didn't believe byond could do it without exploding
+			if(!world.OpenPort(new_port))
+				return TopicResponse("Port change failed!")
+
+			return TopicResponse()
+
+		if(DMAPI5_TOPIC_COMMAND_CHANGE_REBOOT_STATE)
+			var/new_reboot_mode = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_REBOOT_STATE]
+			if(!isnum(new_reboot_mode))
+				return TopicResponse("Invalid or missing [DMAPI5_TOPIC_PARAMETER_NEW_REBOOT_STATE]!")
+
+			if(event_handler != null)
+				event_handler.HandleEvent(TGS_EVENT_REBOOT_MODE_CHANGE, reboot_mode, new_reboot_mode)
+
+			reboot_mode = new_reboot_mode
+			return TopicResponse()
+
+		if(DMAPI5_TOPIC_COMMAND_INSTANCE_RENAMED)
+			var/new_instance_name = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_INSTANCE_NAME]
+			if(!istext(new_instance_name))
+				return TopicResponse("Invalid or missing [DMAPI5_TOPIC_PARAMETER_NEW_INSTANCE_NAME]!")
+
+			if(event_handler != null)
+				event_handler.HandleEvent(TGS_EVENT_INSTANCE_RENAMED, new_instance_name)
+
+			instance_name = new_instance_name
+			return TopicResponse()
+
+		if(DMAPI5_TOPIC_COMMAND_CHAT_CHANNELS_UPDATE)
+			var/list/chat_update_json = topic_parameters[DMAPI5_TOPIC_PARAMETER_CHAT_UPDATE]
+			if(!istype(chat_update_json))
+				return TopicResponse("Invalid or missing [DMAPI5_TOPIC_PARAMETER_CHAT_UPDATE]!")
+
+			DecodeChannels(chat_update_json)
+			return TopicResponse()
+
+		if(DMAPI5_TOPIC_COMMAND_SERVER_PORT_UPDATE)
+			var/new_port = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_PORT]
+			if (!isnum(new_port) || !(new_port > 0))
+				return TopicResponse("Invalid or missing [DMAPI5_TOPIC_PARAMETER_NEW_PORT]]")
+
+			server_port = new_port
+			return TopicResponse()
+
+		if(DMAPI5_TOPIC_COMMAND_HEARTBEAT)
+			return TopicResponse()
+
+		if(DMAPI5_TOPIC_COMMAND_WATCHDOG_REATTACH)
+			detached = FALSE
+			var/new_port = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_PORT]
+			var/error_message = null
+			if (new_port != null)
+				if (!isnum(new_port) || !(new_port > 0))
+					error_message = "Invalid [DMAPI5_TOPIC_PARAMETER_NEW_PORT]]"
+				else
+					server_port = new_port
+
+			var/new_version_string = topic_parameters[DMAPI5_TOPIC_PARAMETER_NEW_SERVER_VERSION]
+			if (!istext(new_version_string))
+				if(error_message != null)
+					error_message += ", "
+				error_message += "Invalid or missing [DMAPI5_TOPIC_PARAMETER_NEW_SERVER_VERSION]]"
+			else
+				var/datum/tgs_version/new_version = new(new_version_string)
+				if (event_handler)
+					event_handler.HandleEvent(TGS_EVENT_WATCHDOG_REATTACH, new_version)
+
+				version = new_version
+
+			var/list/reattach_response = TopicResponse(error_message)
+			reattach_response[DMAPI5_PARAMETER_CUSTOM_COMMANDS] = ListCustomCommands()
+			return reattach_response
+
+		if(DMAPI5_TOPIC_COMMAND_SEND_CHUNK)
+			var/list/chunk = topic_parameters[DMAPI5_CHUNK]
+			if(!istype(chunk))
+				return TopicResponse("Invalid [DMAPI5_CHUNK]!")
+
+			var/payload_id = chunk[DMAPI5_CHUNK_PAYLOAD_ID]
+			if(!isnum(payload_id))
+				return TopicResponse("[DMAPI5_CHUNK_PAYLOAD_ID] is not a number!")
+
+			// Always updated the highest known payload ID
+			chunked_requests = max(chunked_requests, payload_id)
+
+			var/sequence_id = chunk[DMAPI5_CHUNK_SEQUENCE_ID]
+			if(!isnum(sequence_id))
+				return TopicResponse("[DMAPI5_CHUNK_SEQUENCE_ID] is not a number!")
+
+			var/total_chunks = chunk[DMAPI5_CHUNK_TOTAL]
+			if(!isnum(total_chunks))
+				return TopicResponse("[DMAPI5_CHUNK_TOTAL] is not a number!")
+
+			if(total_chunks == 0)
+				return TopicResponse("[DMAPI5_CHUNK_TOTAL] is zero!")
+
+			var/payload = chunk[DMAPI5_CHUNK_PAYLOAD]
+			if(!istext(payload))
+				return TopicResponse("[DMAPI5_CHUNK_PAYLOAD] is not text!")
+
+			var/cache_key = "request[payload_id]"
+			var/payloads = chunked_topics[cache_key]
+
+			if(!payloads)
+				payloads = new /list(total_chunks)
+				chunked_topics[cache_key] = payloads
+
+			if(total_chunks != length(payloads))
+				chunked_topics -= cache_key
+				return TopicResponse("Received differing total chunks for same [DMAPI5_CHUNK_PAYLOAD_ID]! Invalidating [DMAPI5_CHUNK_PAYLOAD_ID]!")
+
+			var/pre_existing_chunk = payloads[sequence_id + 1]
+			if(pre_existing_chunk && pre_existing_chunk != payload)
+				chunked_topics -= cache_key
+				return TopicResponse("Received differing payload for same [DMAPI5_CHUNK_SEQUENCE_ID]! Invalidating [DMAPI5_CHUNK_PAYLOAD_ID]!")
+
+			payloads[sequence_id + 1] = payload
+
+			var/list/missing_sequence_ids = list()
+			for(var/i in 1 to total_chunks)
+				if(!payloads[i])
+					missing_sequence_ids += i - 1
+
+			if(length(missing_sequence_ids))
+				return list(DMAPI5_MISSING_CHUNKS = missing_sequence_ids)
+
+			chunked_topics -= cache_key
+			var/full_json = jointext(payloads, "")
+
+			return ProcessRawTopic(full_json, FALSE)
+
+		if(DMAPI5_TOPIC_COMMAND_RECEIVE_CHUNK)
+			var/payload_id = topic_parameters[DMAPI5_CHUNK_PAYLOAD_ID]
+			if(!isnum(payload_id))
+				return TopicResponse("[DMAPI5_CHUNK_PAYLOAD_ID] is not a number!")
+
+			// Always updated the highest known payload ID
+			chunked_requests = max(chunked_requests, payload_id)
+
+			var/list/missing_chunks = topic_parameters[DMAPI5_MISSING_CHUNKS]
+			if(!istype(missing_chunks) || !length(missing_chunks))
+				return TopicResponse("Missing or empty [DMAPI5_MISSING_CHUNKS]!")
+
+			var/sequence_id_to_send = missing_chunks[1]
+			if(!isnum(sequence_id_to_send))
+				return TopicResponse("[DMAPI5_MISSING_CHUNKS] contained a non-number!")
+
+			var/cache_key = ResponseTopicChunkCacheKey(payload_id)
+			var/list/chunks = chunked_topics[cache_key]
+			if(!chunks)
+				return TopicResponse("Unknown response chunk set: P[payload_id]!")
+
+			// sequence IDs in interop chunking are always zero indexed
+			var/chunk_to_send = chunks[sequence_id_to_send + 1]
+			if(!chunk_to_send)
+				return TopicResponse("Sequence ID [sequence_id_to_send] is not present in response chunk P[payload_id]!")
+
+			if(length(missing_chunks) == 1)
+				// sending last chunk, purge the cache
+				chunked_topics -= cache_key
+
+			return chunk_to_send
+
+	return TopicResponse("Unknown command: [command]")
diff --git a/tgs_dmapi/tgs/v5/undefs.dm b/tgs_dmapi/tgs/v5/undefs.dm
index 5885a60e75c..e3455b69d1c 100644
--- a/tgs_dmapi/tgs/v5/undefs.dm
+++ b/tgs_dmapi/tgs/v5/undefs.dm
@@ -4,16 +4,29 @@
 #undef DMAPI5_BRIDGE_DATA
 #undef DMAPI5_TOPIC_DATA
 
+#undef DMAPI5_BRIDGE_REQUEST_LIMIT
+#undef DMAPI5_TOPIC_REQUEST_LIMIT
+#undef DMAPI5_TOPIC_RESPONSE_LIMIT
+
 #undef DMAPI5_BRIDGE_COMMAND_PORT_UPDATE
 #undef DMAPI5_BRIDGE_COMMAND_STARTUP
 #undef DMAPI5_BRIDGE_COMMAND_PRIME
 #undef DMAPI5_BRIDGE_COMMAND_REBOOT
 #undef DMAPI5_BRIDGE_COMMAND_KILL
 #undef DMAPI5_BRIDGE_COMMAND_CHAT_SEND
+#undef DMAPI5_BRIDGE_COMMAND_CHUNK
 
 #undef DMAPI5_PARAMETER_ACCESS_IDENTIFIER
 #undef DMAPI5_PARAMETER_CUSTOM_COMMANDS
 
+#undef DMAPI5_CHUNK
+#undef DMAPI5_CHUNK_PAYLOAD
+#undef DMAPI5_CHUNK_TOTAL
+#undef DMAPI5_CHUNK_SEQUENCE_ID
+#undef DMAPI5_CHUNK_PAYLOAD_ID
+
+#undef DMAPI5_MISSING_CHUNKS
+
 #undef DMAPI5_RESPONSE_ERROR_MESSAGE
 
 #undef DMAPI5_BRIDGE_PARAMETER_COMMAND_TYPE
@@ -25,7 +38,6 @@
 #undef DMAPI5_BRIDGE_RESPONSE_NEW_PORT
 #undef DMAPI5_BRIDGE_RESPONSE_RUNTIME_INFORMATION
 
-#undef DMAPI5_CHAT_MESSAGE_TEXT
 #undef DMAPI5_CHAT_MESSAGE_CHANNEL_IDS
 
 #undef DMAPI5_RUNTIME_INFORMATION_ACCESS_IDENTIFIER
@@ -75,6 +87,7 @@
 #undef DMAPI5_TOPIC_PARAMETER_CHAT_UPDATE
 #undef DMAPI5_TOPIC_PARAMETER_NEW_SERVER_VERSION
 
+#undef DMAPI5_TOPIC_RESPONSE_COMMAND_RESPONSE
 #undef DMAPI5_TOPIC_RESPONSE_COMMAND_RESPONSE_MESSAGE
 #undef DMAPI5_TOPIC_RESPONSE_CHAT_RESPONSES
 
@@ -93,6 +106,7 @@
 #undef DMAPI5_CHAT_CHANNEL_IS_ADMIN_CHANNEL
 #undef DMAPI5_CHAT_CHANNEL_IS_PRIVATE_CHANNEL
 #undef DMAPI5_CHAT_CHANNEL_TAG
+#undef DMAPI5_CHAT_CHANNEL_EMBEDS_SUPPORTED
 
 #undef DMAPI5_CUSTOM_CHAT_COMMAND_NAME
 #undef DMAPI5_CUSTOM_CHAT_COMMAND_HELP_TEXT

From b4fdbf3e6a5b8d8811c015567e6a03e7c938937a Mon Sep 17 00:00:00 2001
From: k5 <kfive@kfive.ca>
Date: Sat, 29 Apr 2023 02:45:27 -0400
Subject: [PATCH 5/6] Oops.

---
 code/controllers/master.dm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/code/controllers/master.dm b/code/controllers/master.dm
index 0278f8cb2f5..88b7c8a52f6 100755
--- a/code/controllers/master.dm
+++ b/code/controllers/master.dm
@@ -228,7 +228,7 @@ GLOBAL_REAL(Master, /datum/controller/master) = new
 
 	world.TgsInitializationComplete()
 
-	world.TgsTargetedChatBroadcast(new /datum/tgs_message_content{text = "A new round has begun!"})
+	world.TgsTargetedChatBroadcast(new /datum/tgs_message_content{text = "A new round has begun!"}())
 
 	// Sort subsystems by display setting for easy access.
 	sortTim(subsystems, /proc/cmp_subsystem_display)

From d75a990091a8823969244a9faf56456654c9074a Mon Sep 17 00:00:00 2001
From: k5 <kfive@kfive.ca>
Date: Sun, 30 Apr 2023 00:13:55 -0400
Subject: [PATCH 6/6] Double oops.

---
 code/controllers/master.dm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/code/controllers/master.dm b/code/controllers/master.dm
index 88b7c8a52f6..f3daac1390f 100755
--- a/code/controllers/master.dm
+++ b/code/controllers/master.dm
@@ -228,7 +228,7 @@ GLOBAL_REAL(Master, /datum/controller/master) = new
 
 	world.TgsInitializationComplete()
 
-	world.TgsTargetedChatBroadcast(new /datum/tgs_message_content{text = "A new round has begun!"}())
+	world.TgsTargetedChatBroadcast(new /datum/tgs_message_content(text = "A new round has begun!"))
 
 	// Sort subsystems by display setting for easy access.
 	sortTim(subsystems, /proc/cmp_subsystem_display)