1 files changed, 82 insertions, 0 deletions
diff --git a/server.erl b/server.erl
new file mode 100644
index 0000000..dbf4182
--- /dev/null
+++ b/server.erl
@@ -0,0 +1,82 @@
+-module(server).
+-export([server/2, manager/1, broadcast/2, broadcast/3, worker/2, create_workers/2]).
+
+server(Port, NumWorkers) ->
+    process_flag(trap_exit, true),
+    {ok, ServerSock} = gen_tcp:listen(Port, [list]),
+    spawn(?MODULE, create_workers, [NumWorkers, self()]),
+    supervisor(ServerSock, []).
+
+create_workers(0, _) -> ok;
+create_workers(Num, Supervisor) ->
+    Supervisor ! create,
+    create_workers(Num - 1, Supervisor).
+
+supervisor(ServerSock, Pids) ->
+    receive
+        create ->
+            io:format("Creating new worker\n"),
+            NewPid = spawn_link(?MODULE, worker, [ServerSock, Pids]),
+            ping_all(Pids, NewPid),
+            supervisor(ServerSock, [NewPid | Pids]);
+        {'EXIT', From, Reason} ->
+            io:format("~p exited due to ~p\n", [From, Reason]),
+            self() ! create,
+            supervisor(ServerSock, lists:delete(From, Pids))
+    end.
+
+ping_all([Pid|Pids], NewPid) ->
+    Pid ! { ping, NewPid },
+    ping_all(Pids, NewPid);
+ping_all([], _) -> ok.
+
+worker(ServerSock, Pids) ->
+    process_flag(trap_exit, false),
+    ManagerPid = self(),
+    spawn_link(
+        fun() ->
+           process_flag(trap_exit, false),
+           listener(ManagerPid, ServerSock)
+        end),
+    manager(Pids).
+
+listener(ManagerPid, ServerSock) ->
+    case gen_tcp:accept(ServerSock) of
+        {ok, Sock} ->
+            ok = gen_tcp:controlling_process(Sock, ManagerPid),
+            ManagerPid ! {ping, Sock},
+            listener(ManagerPid, ServerSock);
+        Other ->
+            exit(Other)
+    end.
+
+manager(Socks) ->
+    receive
+        {tcp, Sock, Data} ->
+            broadcast(lists:delete(Sock, Socks), Data),
+            manager(Socks);
+        {tcp_closed, Sock} -> 
+            manager(lists:delete(Sock, Socks));
+        {ping, Sock} ->
+            manager([Sock | Socks]);
+
+        {repeat, Data} ->
+            broadcast(Socks, Data, norepeat),
+            manager(Socks);
+        Other ->
+            exit(Other)
+    end.
+
+broadcast([Pid|Socks], Data, norepeat) when is_pid(Pid) ->
+    broadcast(Socks, Data, norepeat);
+broadcast([Pid|Socks], Data, Opt) when is_pid(Pid) ->
+    Pid ! {repeat, Data},
+    broadcast(Socks, Data, Opt);
+
+broadcast([Sock|Socks], Data, Opt)  ->
+    gen_tcp:send(Sock, Data),
+    broadcast(Socks, Data, Opt);
+broadcast([], _, _) -> ok.
+
+broadcast(Socks, Data) ->
+    broadcast(Socks, Data, ok).