9 files changed, 108 insertions, 3 deletions

diff --git a/builtin/client/chatcommands.lua b/builtin/client/chatcommands.lua
index 20f98a293..ed43a6140 100644
--- a/builtin/client/chatcommands.lua
+++ b/builtin/client/chatcommands.lua
@@ -51,3 +51,15 @@ core.register_chatcommand("disconnect", {
 		core.disconnect()
 	end,
 })
+
+core.register_chatcommand("clear_chat_queue", {
+	description = core.gettext("Clear the out chat queue"),
+	func = function(param)
+		core.clear_out_chat_queue()
+		return true, core.gettext("The out chat queue is now empty")
+	end,
+})
+
+function core.run_server_chatcommand(cmd, param)
+	core.send_chat_message("/" .. cmd .. " " .. param)
+end
diff --git a/builtin/settingtypes.txt b/builtin/settingtypes.txt
index 6dd3e825b..c710afdcf 100644
--- a/builtin/settingtypes.txt
+++ b/builtin/settingtypes.txt
@@ -315,6 +315,9 @@ serverlist_url (Serverlist URL) string servers.minetest.net
 #    File in client/serverlist/ that contains your favorite servers displayed in the Multiplayer Tab.
 serverlist_file (Serverlist file) string favoriteservers.txt
 
+#    Maximum size of the out chat queue. 0 to disable queueing and -1 to make the queue size unlimited
+max_out_chat_queue_size (Maximum size of the out chat queue) int 20
+
 [*Graphics]
 
 [**In-Game]
diff --git a/doc/client_lua_api.md b/doc/client_lua_api.md
index e2841dac1..3bd1e3567 100644
--- a/doc/client_lua_api.md
+++ b/doc/client_lua_api.md
@@ -721,6 +721,12 @@ Call these functions only at load time!
 ### Player
 * `minetest.get_wielded_item()`
     * Returns the itemstack the local player is holding
+* `minetest.send_chat_message(message)`
+    * Act as if `message` was typed by the player into the terminal.
+* `minetest.run_server_chatcommand(cmd, param)`
+    * Alias for `minetest.send_chat_message("/" .. cmd .. " " .. param)`
+* `minetest.clear_out_chat_queue()`
+    * Clears the out chat queue
 * `minetest.localplayer`
     * Reference to the LocalPlayer object. See [`LocalPlayer`](#localplayer) class reference for methods.
 
diff --git a/minetest.conf.example b/minetest.conf.example
index d6a57d681..d7c309c6d 100644
--- a/minetest.conf.example
+++ b/minetest.conf.example
@@ -343,6 +343,10 @@
 #    type: string
 # serverlist_file = favoriteservers.txt
 
+#    Maximum size of the out chat queue. 0 to disable queueing and -1 to make the queue size unlimited
+#    type: int
+# max_out_chat_queue_size = 20
+
 ## Graphics
 
 ### In-Game
diff --git a/src/client.cpp b/src/client.cpp
index d0c90b108..0f689a714 100644
--- a/src/client.cpp
+++ b/src/client.cpp
@@ -83,6 +83,7 @@ Client::Client(
 	m_con(PROTOCOL_ID, 512, CONNECTION_TIMEOUT, ipv6, this),
 	m_address_name(address_name),
 	m_server_ser_ver(SER_FMT_VER_INVALID),
+	m_last_chat_message_sent(time(NULL)),
 	m_password(password),
 	m_chosen_auth_mech(AUTH_MECHANISM_NONE),
 	m_media_downloader(new ClientMediaDownloader()),
@@ -388,6 +389,14 @@ void Client::step(float dtime)
 	}
 
 	/*
+		Send pending messages on out chat queue
+	*/
+	if (!m_out_chat_queue.empty() && canSendChatMessage()) {
+		sendChatMessage(m_out_chat_queue.front());
+		m_out_chat_queue.pop();
+	}
+
+	/*
 		Handle environment
 	*/
 	// Control local player (0ms)
@@ -1143,13 +1152,50 @@ void Client::sendInventoryAction(InventoryAction *a)
 	Send(&pkt);
 }
 
+bool Client::canSendChatMessage() const
+{
+	u32 now = time(NULL);
+	float time_passed = now - m_last_chat_message_sent;
+
+	float virt_chat_message_allowance = m_chat_message_allowance + time_passed *
+			(CLIENT_CHAT_MESSAGE_LIMIT_PER_10S / 8.0f);
+
+	if (virt_chat_message_allowance < 1.0f)
+		return false;
+
+	return true;
+}
+
 void Client::sendChatMessage(const std::wstring &message)
 {
-	NetworkPacket pkt(TOSERVER_CHAT_MESSAGE, 2 + message.size() * sizeof(u16));
+	const s16 max_queue_size = g_settings->getS16("max_out_chat_queue_size");
+	if (canSendChatMessage()) {
+		u32 now = time(NULL);
+		float time_passed = now - m_last_chat_message_sent;
+		m_last_chat_message_sent = time(NULL);
 
-	pkt << message;
+		m_chat_message_allowance += time_passed * (CLIENT_CHAT_MESSAGE_LIMIT_PER_10S / 8.0f);
+		if (m_chat_message_allowance > CLIENT_CHAT_MESSAGE_LIMIT_PER_10S)
+			m_chat_message_allowance = CLIENT_CHAT_MESSAGE_LIMIT_PER_10S;
 
-	Send(&pkt);
+		m_chat_message_allowance -= 1.0f;
+
+		NetworkPacket pkt(TOSERVER_CHAT_MESSAGE, 2 + message.size() * sizeof(u16));
+
+		pkt << message;
+
+		Send(&pkt);
+	} else if (m_out_chat_queue.size() < (u16) max_queue_size || max_queue_size == -1) {
+		m_out_chat_queue.push(message);
+	} else {
+		infostream << "Could not queue chat message because maximum out chat queue size ("
+				<< max_queue_size << ") is reached." << std::endl;
+	}
+}
+
+void Client::clearOutChatQueue()
+{
+	m_out_chat_queue = std::queue<std::wstring>();
 }
 
 void Client::sendChangePassword(const std::string &oldpassword,
diff --git a/src/client.h b/src/client.h
index 29cbe9c10..0255b2803 100644
--- a/src/client.h
+++ b/src/client.h
@@ -40,6 +40,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <fstream>
 #include "filesys.h"
 
+#define CLIENT_CHAT_MESSAGE_LIMIT_PER_10S 10.0f
+
 struct MeshMakeData;
 class MapBlockMesh;
 class IWritableTextureSource;
@@ -373,6 +375,7 @@ public:
 		const StringMap &fields);
 	void sendInventoryAction(InventoryAction *a);
 	void sendChatMessage(const std::wstring &message);
+	void clearOutChatQueue();
 	void sendChangePassword(const std::string &oldpassword,
 		const std::string &newpassword);
 	void sendDamage(u8 damage);
@@ -579,6 +582,8 @@ private:
 	inline std::string getPlayerName()
 	{ return m_env.getLocalPlayer()->getName(); }
 
+	bool canSendChatMessage() const;
+
 	float m_packetcounter_timer = 0.0f;
 	float m_connection_reinit_timer = 0.1f;
 	float m_avg_rtt_timer = 0.0f;
@@ -625,6 +630,9 @@ private:
 	//s32 m_daynight_i;
 	//u32 m_daynight_ratio;
 	std::queue<std::wstring> m_chat_queue;
+	std::queue<std::wstring> m_out_chat_queue;
+	u32 m_last_chat_message_sent;
+	float m_chat_message_allowance = 5.0f;
 
 	// The authentication methods we can use to enter sudo mode (=change password)
 	u32 m_sudo_auth_methods;
diff --git a/src/defaultsettings.cpp b/src/defaultsettings.cpp
index 54043cf75..5206d19eb 100644
--- a/src/defaultsettings.cpp
+++ b/src/defaultsettings.cpp
@@ -57,6 +57,7 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("curl_verify_cert", "true");
 	settings->setDefault("enable_remote_media_server", "true");
 	settings->setDefault("enable_client_modding", "false");
+	settings->setDefault("max_out_chat_queue_size", "20");
 
 	// Keymap
 	settings->setDefault("remote_port", "30000");
diff --git a/src/script/lua_api/l_client.cpp b/src/script/lua_api/l_client.cpp
index 0b957a6e2..1077d5f2d 100644
--- a/src/script/lua_api/l_client.cpp
+++ b/src/script/lua_api/l_client.cpp
@@ -85,6 +85,23 @@ int ModApiClient::l_display_chat_message(lua_State *L)
 	return 1;
 }
 
+// send_chat_message(message)
+int ModApiClient::l_send_chat_message(lua_State *L)
+{
+	if (!lua_isstring(L, 1))
+		return 0;
+	std::string message = luaL_checkstring(L, 1);
+	getClient(L)->sendChatMessage(utf8_to_wide(message));
+	return 0;
+}
+
+// clear_out_chat_queue()
+int ModApiClient::l_clear_out_chat_queue(lua_State *L)
+{
+	getClient(L)->clearOutChatQueue();
+	return 0;
+}
+
 // get_player_names()
 int ModApiClient::l_get_player_names(lua_State *L)
 {
@@ -337,6 +354,8 @@ void ModApiClient::Initialize(lua_State *L, int top)
 	API_FCT(get_current_modname);
 	API_FCT(print);
 	API_FCT(display_chat_message);
+	API_FCT(send_chat_message);
+	API_FCT(clear_out_chat_queue);
 	API_FCT(get_player_names);
 	API_FCT(set_last_run_mod);
 	API_FCT(get_last_run_mod);
diff --git a/src/script/lua_api/l_client.h b/src/script/lua_api/l_client.h
index 6bb12187f..7472915f5 100644
--- a/src/script/lua_api/l_client.h
+++ b/src/script/lua_api/l_client.h
@@ -37,6 +37,12 @@ private:
 	// display_chat_message(message)
 	static int l_display_chat_message(lua_State *L);
 
+	// send_chat_message(message)
+	static int l_send_chat_message(lua_State *L);
+
+	// clear_out_chat_queue()
+	static int l_clear_out_chat_queue(lua_State *L);
+
 	// get_player_names()
 	static int l_get_player_names(lua_State *L);