(**************************************************************************)
(*                                                                        *)
(*    Copyright (c) 2014 - 2016.                                          *)
(*    Dynamic Ledger Solutions, Inc. <contact@tezos.com>                  *)
(*                                                                        *)
(*    All rights reserved. No warranty, explicit or implicit, provided.   *)
(*                                                                        *)
(**************************************************************************)

open Error_monad
open P2p_types
include Logging.Make (struct let name = "test.p2p.connection-pool" end)

type message =
  | Ping


let msg_config : message P2p_connection_pool.message_config = {
  encoding = [
    P2p_connection_pool.Encoding {
      tag = 0x10 ;
      encoding = Data_encoding.empty ;
      wrap = (function () -> Ping) ;
      unwrap = (function Ping -> Some ()) ;
      max_length = None ;
    } ;
  ] ;
  versions =  Version.[ { name = "TEST" ; major = 0 ; minor = 0 } ] ;
}

type metadata = unit

let meta_config : metadata P2p_connection_pool.meta_config = {
  encoding = Data_encoding.empty ;
  initial = () ;
  score = fun () -> 0. ;
}

let sync ch =
  Process.Channel.push ch () >>=? fun () ->
  Process.Channel.pop ch >>=? fun () ->
  return ()

let rec sync_nodes nodes =
  iter_p
    (fun { Process.channel } -> Process.Channel.pop channel)
    nodes >>=? fun () ->
  iter_p
    (fun { Process.channel } -> Process.Channel.push channel ())
    nodes >>=? fun () ->
  sync_nodes nodes

let sync_nodes nodes =
  sync_nodes nodes >>= function
  | Ok () | Error (Exn End_of_file :: _) ->
      return ()
  | Error e as err ->
      Lwt.return err

let detach_node f points n =
  let (addr, port), points = Utils.select n points in
  let proof_of_work_target = Crypto_box.make_target 0. in
  let identity = Identity.generate proof_of_work_target in
  let nb_points = List.length points in
  let config = P2p_connection_pool.{
    identity ;
    proof_of_work_target ;
    trusted_points = points ;
    peers_file = "/dev/null" ;
    closed_network = true ;
    listening_port = Some port ;
    min_connections = nb_points ;
    max_connections = nb_points ;
    max_incoming_connections = nb_points ;
    authentification_timeout = 2. ;
    incoming_app_message_queue_size = None ;
    incoming_message_queue_size = None ;
    outgoing_message_queue_size = None ;
    known_peer_ids_history_size = 100 ;
    known_points_history_size = 100 ;
    max_known_points = None ;
    max_known_peer_ids = None ;
    swap_linger = 0. ;
    } in
  Process.detach
    ~prefix:(Format.asprintf "%a: " Peer_id.pp_short identity.peer_id)
    begin fun channel ->
      let sched = P2p_io_scheduler.create ~read_buffer_size:(1 lsl 12) () in
      P2p_connection_pool.create
        config meta_config msg_config sched >>= fun pool ->
      P2p_welcome.run ~backlog:10 pool ~addr port >>= fun welcome ->
      lwt_log_info "Node ready (port: %d)" port >>= fun () ->
      sync channel >>=? fun () ->
      f channel pool points >>=? fun () ->
      lwt_log_info "Shutting down..." >>= fun () ->
      P2p_welcome.shutdown welcome >>= fun () ->
      P2p_connection_pool.destroy pool >>= fun () ->
      P2p_io_scheduler.shutdown sched >>= fun () ->
      lwt_log_info "Bye." >>= fun () ->
      return ()
    end

let detach_nodes ?(sync = 0) run_node points =
  let open Utils in
  let clients = List.length points in
  Lwt_list.map_p
    (detach_node run_node points) (0 -- (clients - 1)) >>= fun nodes ->
  Lwt.ignore_result (sync_nodes nodes) ;
  Process.wait_all nodes

type error += Connect | Write | Read

module Simple = struct

  let rec connect ~timeout pool point =
    lwt_log_info "Connect to %a" Point.pp point >>= fun () ->
    P2p_connection_pool.connect pool point ~timeout >>= function
    | Error [P2p_connection_pool.Connected] -> begin
        match P2p_connection_pool.Connection.find_by_point pool point with
        | Some conn -> return conn
        | None -> failwith "Woops..."
      end
    | Error ([ P2p_connection_pool.Connection_refused
             | P2p_connection_pool.Pending_connection
             | P2p_connection.Rejected
             | Lwt_utils.Canceled
             | Lwt_utils.Timeout
             | P2p_connection_pool.Rejected _
             ] as err) ->
        lwt_log_info "@[Connection to %a failed:@ %a@]"
          Point.pp point pp_print_error err >>= fun () ->
        Lwt_unix.sleep (0.5 +. Random.float 2.) >>= fun () ->
        connect ~timeout pool point
    | Ok _ | Error _ as res -> Lwt.return res

  let connect_all ~timeout pool points =
    map_p (connect ~timeout pool) points

  let write_all conns msg  =
    iter_p
      (fun conn ->
         trace Write @@ P2p_connection_pool.write_sync conn msg)
      conns

  let read_all conns =
    iter_p
      (fun conn ->
         trace Read @@ P2p_connection_pool.read conn >>=? fun Ping ->
         return ())
      conns

  let close_all conns =
    Lwt_list.iter_p P2p_connection_pool.disconnect conns

  let node channel pool points =
    connect_all ~timeout:2. pool points >>=? fun conns ->
    lwt_log_info "Bootstrap OK" >>= fun () ->
    sync channel >>=? fun () ->
    write_all conns Ping >>=? fun () ->
    lwt_log_info "Sent all messages." >>= fun () ->
    sync channel >>=? fun () ->
    read_all conns >>=? fun () ->
    lwt_log_info "Read all messages." >>= fun () ->
    sync channel >>=? fun () ->
    close_all conns >>= fun () ->
    lwt_log_info "All connections successfully closed." >>= fun () ->
    return ()

  let run points = detach_nodes node points

end

module Random_connections = struct

  let rec connect_random pool total rem point n =
    Lwt_unix.sleep (0.2 +. Random.float 1.0) >>= fun () ->
    (trace Connect @@ Simple.connect ~timeout:2. pool point) >>=? fun conn ->
    (trace Write @@ P2p_connection_pool.write conn Ping) >>= fun _ ->
    (trace Read @@ P2p_connection_pool.read conn) >>=? fun Ping ->
    Lwt_unix.sleep (0.2 +. Random.float 1.0) >>= fun () ->
    P2p_connection_pool.disconnect conn >>= fun () ->
    begin
      decr rem ;
      if !rem mod total = 0 then
        lwt_log_info "Remaining: %d." (!rem / total)
      else
        Lwt.return ()
    end >>= fun () ->
    if n > 1 then
      connect_random pool total rem point (pred n)
    else
      return ()

  let connect_random_all pool points n =
    let total = List.length points in
    let rem = ref (n * total) in
    iter_p (fun point -> connect_random pool total rem point n) points

  let node repeat channel pool points =
    lwt_log_info "Begin random connections." >>= fun () ->
    connect_random_all pool points repeat >>=? fun () ->
    lwt_log_info "Random connections OK." >>= fun () ->
    return ()

  let run points repeat = detach_nodes (node repeat) points

end

let addr = ref Ipaddr.V6.localhost
let port = ref (1024 + Random.int 8192)
let clients = ref 10
let repeat_connections = ref 5

let spec = Arg.[

    "--port", Int (fun p -> port := p), " Listening port of the first peer.";

    "--addr", String (fun p -> addr := Ipaddr.V6.of_string_exn p),
    " Listening addr";

    "--clients", Set_int clients,  " Number of concurrent clients." ;

    "--repeat", Set_int repeat_connections,
    " Number of connections/disconnections." ;


    "-v", Unit (fun () ->
        Lwt_log_core.(add_rule "test.p2p.connection-pool" Info) ;
        Lwt_log_core.(add_rule "p2p.connection-pool" Info)),
    " Log up to info msgs" ;

    "-vv", Unit (fun () ->
        Lwt_log_core.(add_rule "test.p2p.connection-pool" Debug) ;
        Lwt_log_core.(add_rule "p2p.connection-pool" Debug)),
    " Log up to debug msgs";

  ]

let main () =
  let open Utils in
  let anon_fun num_peers = raise (Arg.Bad "No anonymous argument.") in
  let usage_msg = "Usage: %s <num_peers>.\nArguments are:" in
  Arg.parse spec anon_fun usage_msg ;
  let ports = !port -- (!port + !clients - 1) in
  let points = List.map (fun port -> !addr, port) ports in
  Test.run "p2p-connection-pool." [
    "simple", (fun _ -> Simple.run points) ;
    "random", (fun _ -> Random_connections.run points !repeat_connections) ;
  ]

let () =
  Sys.catch_break true ;
  try main ()
  with _ -> ()