(* Copyright 2012 Tony Garnock-Jones <tonygarnockjones@gmail.com>. *)

(* This file is part of Hop. *)

(* Hop is free software: you can redistribute it and/or modify it *)
(* under the terms of the GNU General Public License as published by the *)
(* Free Software Foundation, either version 3 of the License, or (at your *)
(* option) any later version. *)

(* Hop 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 *)
(* General Public License for more details. *)

(* You should have received a copy of the GNU General Public License *)
(* along with Hop.  If not, see <http://www.gnu.org/licenses/>. *)

open Lwt
open Unix
open Printf
open Sexp

let connection_count = ref 0

let endpoint_name n =
  match n with
  | ADDR_INET (host, port) -> sprintf "%s:%d" (string_of_inet_addr host) port
  | _ -> "??unknown??"

let connection_main class_name peername cin cout issue_banner boot_fn node_fn mainloop =
  ignore (Log.info ("Accepted "^class_name) [str (endpoint_name peername)]);
  match_lwt issue_banner cin cout with
    | true ->
      lwt shared_state = boot_fn (peername, cin, cout) in
      let n = Node.make (Bytes.of_string class_name) (node_fn shared_state) in
      lwt () =
	(try_lwt
	   mainloop shared_state n
	 with
	   | End_of_file ->
	     Log.info ("Disconnecting "^class_name^" normally") [str (endpoint_name peername)]
	   | Sys_error message ->
	     Log.warn ("Disconnected "^class_name^" by Sys_error") [str (endpoint_name peername); str message]
	   | exn ->
	     Log.error ("Uncaught exception in "^class_name) [str (Printexc.to_string exn)])
      in
      Node.unbind_all n
    | false ->
      Log.error ("Disconnected "^class_name^" by failed initial handshake") []

let start_connection' class_name issue_banner boot_fn node_fn mainloop (s, peername) =
  let cin = Lwt_io.of_fd Lwt_io.input s in
  let cout = Lwt_io.of_fd Lwt_io.output s in
  connection_count := !connection_count + 1;
  lwt () = connection_main class_name peername cin cout issue_banner boot_fn node_fn mainloop in
  connection_count := !connection_count - 1;
  lwt () = (try_lwt Lwt_io.flush cout with _ -> return ()) in
  Lwt_unix.close s

let start_connection class_name issue_banner boot_fn node_fn mainloop (s, peername) =
  Util.create_thread
    (Bytes.of_string (endpoint_name peername ^ " input"))
    None
    (start_connection' class_name issue_banner boot_fn node_fn mainloop)
    (s, peername)