%% Copyright (c) 2016 Contributors as noted in the AUTHORS file
%%
%% This file is part teleport
%%
%% This Source Code Form is subject to the terms of the Mozilla Public
%% License, v. 2.0. If a copy of the MPL was not distributed with this
%% file, You can obtain one at http://mozilla.org/MPL/2.0/.

-module(teleport_server_sup).

-export([
  start_server/2,
  stop_server/1,
  get_port/1,
  get_addr/1,
  get_uri/1,
  server_is_alive/1
]).

-export([start_link/0]).

-export([init/1]).

-include("teleport.hrl").

%%====================================================================
%% API functions
%%====================================================================

start_link() ->
  supervisor:start_link({local, ?MODULE}, ?MODULE, []).

start_server(Name, Config) when is_map(Config) ->
  case supervisor:start_child(?MODULE, server_spec(Name, Config)) of
    {ok, Pid} ->
      lager:info("teleport: start server: ~s [~s]", [get_uri(Name), Name]),
      {ok, Pid};
    {error, {already_started, Pid}} ->
      lager:info("teleport: server already started: ~s [~s]", [get_uri(Name), Name]),
      {ok, Pid}
  end;
start_server(Name, Config) when is_list(Config) ->
  start_server(Name, maps:from_list(Config));
start_server(_, _) -> erlang:error(badarg).

stop_server(Name) ->
  Uri = get_uri(Name),
  case supervisor:terminate_child(?MODULE, listener_name(Name)) of
    ok ->
      _ = supervisor:delete_child(?MODULE, listener_name(Name)),
      ranch_server:cleanup_listener_opts(Name),
      lager:info("teleport: stopped server ~s~n", [Uri]),
      ok;
    Error ->
      lager:error("teleport: error stopping server ~p~n", [Uri]),
      Error
  end.

get_port(Name) -> ranch:get_port(Name).

get_addr(Name) -> ranch:get_addr(Name).

get_uri(Name) ->
  #{host := Host, transport := Transport} = ranch:get_protocol_options(Name),
  Port = get_port(Name),
  Scheme = case Transport of
             ranch_tcp ->"link";
             ranch_ssl -> "slink"
           end,
  UriBin = iolist_to_binary(
    [Scheme, "://", Host, ":", integer_to_list(Port)]
  ),
  binary_to_list(UriBin).

server_is_alive(Name) ->
  case catch ets:lookup_element(ranch_server, {conns_sup, Name}, 2) of
    Pid when is_pid(Pid) -> true;
    _ -> false
  end.

%%====================================================================
%% Supervisor callbacks
%%====================================================================

%% Child :: {Id,StartFunc,Restart,Shutdown,Type,Modules}
init([]) ->
  Servers = application:get_env(teleport, servers, []),
  Specs = lists:map(fun({Name, Config}) ->
      server_spec(Name, Config)
    end, Servers),
  {ok, {{one_for_one, 1, 5}, Specs}}.

server_spec(Name, Config) ->
  {ok, HostName} = inet:gethostname(),
  Host = maps:get(host, Config, HostName),
  Port = maps:get(port, Config, 0),
  NumAcceptors = maps:get(num_acceptors, Config, 100),
  Transport = teleport_lib:parse_transport(Config),
  TransportOpts0 = case Transport of
                     ranch_tcp -> [{backlog, 2048}];
                     ranch_ssl ->
                       Host = maps:get(host, Config, inet:gethostname()),
                       teleport_lib:ssl_conf(server, Host)
                   end,
  TransportOpts = [{port, Port} | TransportOpts0],

  ranch:child_spec(
    Name, NumAcceptors, Transport, TransportOpts,
    teleport_protocol, #{ host => Host, transport => Transport, name => Name}
  ).

listener_name(Name) ->
  {ranch_listener_sup, Name}.