Add server side ncurses terminal

This adds a chat console the server owner can use for administration
or to talk with players.
It runs in its own thread, which makes the user interface immune to
the server's lag, behaving just like a client, except timeout.
As it uses the same console code as the f10 console, things like nick
completion or a scroll buffer basically come for free.
The terminal itself is written in a general way so that adding a
client version later on is just about implementing an interface.

Fatal errors are printed after the console exists and the ncurses
terminal buffer gets cleaned up with endwin(), so that the error still
remains visible.

The server owner can chose their username their entered text will
have in chat and where players can send PMs to.
Once the username is secured with a password to prevent anybody to
take over the server, the owner can execute admin tasks over the
console.

This change includes a contribution by @kahrl who has improved ncurses
library detection.

1 files changed, 82 insertions, 0 deletions

diff --git a/src/chat_interface.h b/src/chat_interface.h
new file mode 100644
index 000000000..4784821fc
--- /dev/null
+++ b/src/chat_interface.h
@@ -0,0 +1,82 @@
+/*
+Minetest
+Copyright (C) 2015 est31 <MTest31@outlook.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#ifndef CHAT_INTERFACE_H
+#define CHAT_INTERFACE_H
+
+#include "util/container.h"
+#include <string>
+#include <queue>
+#include "irrlichttypes.h"
+
+enum ChatEventType {
+	CET_CHAT,
+	CET_NICK_ADD,
+	CET_NICK_REMOVE,
+	CET_TIME_INFO,
+};
+
+class ChatEvent {
+protected:
+	ChatEvent(ChatEventType a_type) { type = a_type; }
+public:
+	ChatEventType type;
+};
+
+struct ChatEventTimeInfo : public ChatEvent {
+	ChatEventTimeInfo(
+		u64 a_game_time,
+		u32 a_time) :
+	ChatEvent(CET_TIME_INFO),
+	game_time(a_game_time),
+	time(a_time)
+	{}
+
+	u64 game_time;
+	u32 time;
+};
+
+struct ChatEventNick : public ChatEvent {
+	ChatEventNick(ChatEventType a_type,
+		const std::string &a_nick) :
+	ChatEvent(a_type), // one of CET_NICK_ADD, CET_NICK_REMOVE
+	nick(a_nick)
+	{}
+
+	std::string nick;
+};
+
+struct ChatEventChat : public ChatEvent {
+	ChatEventChat(const std::string &a_nick,
+		const std::wstring &an_evt_msg) :
+	ChatEvent(CET_CHAT),
+	nick(a_nick),
+	evt_msg(an_evt_msg)
+	{}
+
+	std::string nick;
+	std::wstring evt_msg;
+};
+
+struct ChatInterface {
+	MutexedQueue<ChatEvent *> command_queue; // chat backend --> server
+	MutexedQueue<ChatEvent *> outgoing_queue; // server --> chat backend
+};
+
+#endif