add wesnoth.create_side()

wesnoth.create_side() can create a side while the scenario
is running, this is especially useful for [modification]s
that can not define sides by default.

src/game_state.cpp

@@ -27,6 +27,7 @@
 #include "random_deterministic.hpp"
 #include "reports.hpp"
 #include "scripting/game_lua_kernel.hpp"
+#include "synced_context.hpp"
 #include "teambuilder.hpp"
 #include "units/unit.hpp"
 #include "whiteboard/manager.hpp"
@@ -409,3 +410,47 @@ const game_events::wmi_manager& game_state::get_wml_menu_items() const
 {
 	return this->events_manager_->wml_menu_items();
 }
+
+
+namespace
+{
+	//not really a 'choice' we just need to make sure to inform the server about this.
+class add_side_wml_choice : public synced_context::server_choice
+{
+public:
+	add_side_wml_choice()
+	{
+	}
+
+	/// We are in a game with no mp server and need to do this choice locally
+	virtual config local_choice() const
+	{
+		return config{};
+	}
+
+	/// tThe request which is sent to the mp server.
+	virtual config request() const
+	{
+		return config{};
+	}
+
+	virtual const char* name() const
+	{
+		return "add_side_wml";
+	}
+
+private:
+};
+} // end anon namespace
+
+
+void game_state::add_side_wml(config cfg)
+{
+	cfg["side"] = board_.teams_.size() + 1;
+	//if we want to also allow setting the controller we must update the server code.
+	cfg["controller"] = "null";
+	//TODO: is this it? are there caches which must be cleared?
+	board_.teams_.emplace_back();
+	board_.teams_.back().build(cfg, board_.map(), cfg["gold"].to_int());
+	config choice = synced_context::ask_server_choice(add_side_wml_choice());
+}

src/game_state.hpp

@@ -125,4 +125,7 @@ public:
 
 	/// Checks if any of the sides leaders can recruit at a location
 	bool side_can_recruit_on(int side, map_location loc) const;
+
+	///creates a new side during a game. todo: maybe add parameters like id etc?
+	void add_side_wml(config cfg);
 };

src/scripting/game_lua_kernel.cpp

@@ -773,6 +773,16 @@ int game_lua_kernel::intf_set_variable(lua_State *L)
 	return 0;
 }
 
+
+int game_lua_kernel::intf_create_side(lua_State *L)
+{
+	int new_side_num = board().teams().size() + 1;
+	config cfg = luaW_checkconfig(L, 1);
+	game_state_.add_side_wml(cfg);
+
+	return 0;
+}
+
 int game_lua_kernel::intf_set_menu_item(lua_State *L)
 {
 	game_state_.get_wml_menu_items().set_item(luaL_checkstring(L, 1), luaW_checkvconfig(L,2));
@@ -4213,6 +4223,7 @@ game_lua_kernel::game_lua_kernel(game_state & gs, play_controller & pc, reports
 		{ "is_shrouded",               &dispatch2<&game_lua_kernel::intf_get_fog_or_shroud, false  >        },
 		{ "set_end_campaign_credits",  &dispatch<&game_lua_kernel::intf_set_end_campaign_credits   >        },
 		{ "set_end_campaign_text",     &dispatch<&game_lua_kernel::intf_set_end_campaign_text      >        },
+		{ "create_side",               &dispatch<&game_lua_kernel::intf_create_side                >        },
 		{ "set_next_scenario",         &dispatch<&game_lua_kernel::intf_set_next_scenario          >        },
 		{ "set_terrain",               &dispatch<&game_lua_kernel::intf_set_terrain                >        },
 		{ "set_variable",              &dispatch<&game_lua_kernel::intf_set_variable               >        },

src/scripting/game_lua_kernel.hpp

@@ -128,6 +128,7 @@ class game_lua_kernel : public lua_kernel_base
 	int intf_set_end_campaign_credits(lua_State *L);
 	int intf_set_end_campaign_text(lua_State *L);
 	int intf_clear_menu_item(lua_State *L);
+	int intf_create_side(lua_State *L);
 	int intf_set_menu_item(lua_State *L);
 	int intf_set_next_scenario(lua_State *L);
 	int intf_shroud_op(lua_State *L, bool place_shroud);

src/server/game.cpp

@@ -1168,6 +1168,13 @@ void game::handle_random_choice(const simple_wml::node&)
 	record_data(mdata);
 }
 
+void game::handle_add_side_wml(const simple_wml::node&)
+{
+	++nsides_;
+	side_controllers_.push_back(CONTROLLER::EMPTY);
+	sides_.emplace_back();
+}
+
 void game::handle_controller_choice(const simple_wml::node& req)
 {
 	const std::size_t side_index = req["side"].to_int() - 1;
@@ -1270,6 +1277,8 @@ void game::handle_choice(const simple_wml::node& data, const socket_ptr& user)
 		handle_random_choice(*rand);
 	} else if(const simple_wml::node* ccw = data.child("change_controller_wml")) {
 		handle_controller_choice(*ccw);
+	} else if(const simple_wml::node* asw = data.child("add_side_wml")) {
+		handle_add_side_wml(*asw);
 	} else {
 		send_and_record_server_message("Found unknown server choice request: [" + data.first_child().to_string() + "]");
 	}

src/server/game.hpp

@@ -315,6 +315,8 @@ public:
 
 	void handle_controller_choice(const simple_wml::node& data);
 
+	void handle_add_side_wml(const simple_wml::node& req);
+
 	void reset_last_synced_context_id()
 	{
 		last_choice_request_id_ = -1;