%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2019-2021. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%

-module(net).

%% We should really ifdef this module depending on if we actually built
%% the system with esock support (socket and prim_net), but our doc-building
%% can't handle the "variables" we need (USE_ESOCK). So instead, we just
%% leave everything hanging...
%% If one of the "hanging" functions is called when esock has been disabled,
%% the function will through a 'notsup' error (erlang:error/1).

%% Administrative and utility functions
-export([
	 info/0,
         command/1
        ]).

-export([
         gethostname/0,
         getnameinfo/1, getnameinfo/2,
         getaddrinfo/1, getaddrinfo/2,
         getifaddrs/0,  getifaddrs/1, getifaddrs/2,

         if_name2index/1,
         if_index2name/1,
         if_names/0
        ]).

%% Deprecated functions from the "old" net module
-export([call/4,
	 cast/4,
	 broadcast/3,
	 ping/1,
	 relay/1,
	 sleep/1]).

%% Should we define these here or refer to the prim_net module
-export_type([
              address_info/0,
              ifaddrs/0,
              name_info/0,

              ifaddrs_flag/0,

              name_info_flags/0,
              name_info_flag/0,
              name_info_flag_ext/0,

              network_interface_name/0,
              network_interface_index/0
             ]).


-deprecated({call,      4, "use rpc:call/4 instead"}).
-deprecated({cast,      4, "use rpc:cast/4 instead"}).
-deprecated({broadcast, 3, "use rpc:eval_everywhere/3 instead"}).
-deprecated({ping,      1, "use net_adm:ping/1 instead"}).
-deprecated({relay,     1, "use slave:relay/1 instead"}).
-deprecated({sleep,     1, "use 'receive after T -> ok end' instead"}).


-type ifaddrs_flag() :: up | broadcast | debug | loopback | pointopoint |
                        notrailers | running | noarp | promisc | master | slave |
                        multicast | portsel | automedia | dynamic.

%% Note that not all of these fields are mandatory.
%% Actually there are (error) cases when only the name will be included.
%% And broadaddr and dstaddr are mutually exclusive!

-type ifaddrs() :: #{name      := string(),
                     flags     := [ifaddrs_flag()],
                     addr      := socket:sockaddr(),
                     netmask   := socket:sockaddr(),
                     broadaddr := socket:sockaddr(),
                     dstaddr   := socket:sockaddr()}.

-type ifaddrs_filter()     :: all | default | inet | inet6 | packet |
                              ifaddrs_filter_map() |
                              ifaddrs_filter_fun().
-type ifaddrs_filter_map() :: #{family := default | inet | inet6 | packet | all,
                                flags  := any | [ifaddrs_flag()]}.
-type ifaddrs_filter_fun() :: fun((ifaddrs()) -> boolean()).

-type name_info_flags()         :: [name_info_flag()|name_info_flag_ext()].
-type name_info_flag()          :: namereqd |
                                   dgram |
                                   nofqdn |
                                   numerichost |
                                   numericserv.
%% The following (ext) flags has been removed
%% (as they are deprecated by later version of gcc):
%%    idn_allow_unassigned | idn_use_std3_ascii_rules.
-type name_info_flag_ext()      :: idn.
-type name_info()               :: #{host    := string(),
                                     service := string()}.
-type address_info()            :: #{family   := socket:domain(),
                                     socktype := socket:type(),
                                     protocol := socket:protocol(),
                                     address  := socket:sockaddr()}.
-type network_interface_name()  :: string().
-type network_interface_index() :: non_neg_integer().


%% ===========================================================================
%%
%% D E P R E C A T E D   F U N C T I O N S
%%
%% ===========================================================================

call(N,M,F,A) -> rpc:call(N,M,F,A).
cast(N,M,F,A) -> rpc:cast(N,M,F,A).
broadcast(M,F,A) -> rpc:eval_everywhere(M,F,A).
ping(Node) -> net_adm:ping(Node).
sleep(T) -> receive after T -> ok end.
relay(X) -> slave:relay(X).


%% ===========================================================================
%%
%% Administrative and utility API
%%
%% ===========================================================================

-spec info() -> list().

-ifdef(USE_ESOCK).
info() ->
    prim_net:info().
-else.
info() ->
    erlang:error(notsup).
-endif.


-spec command(Cmd :: term()) -> term().

-ifdef(USE_ESOCK).
command(Cmd) ->
    prim_net:command(Cmd).
-else.
command(_Cmd) ->
    erlang:error(notsup).
-endif.



%% ===========================================================================
%%
%% The proper net API
%%
%% ===========================================================================

%% ===========================================================================
%%
%% gethostname - Get the name of the current host.
%%
%%

-spec gethostname() -> {ok, HostName} | {error, Reason} when
      HostName :: string(),
      Reason   :: term().

-ifdef(USE_ESOCK).
gethostname() ->
    prim_net:gethostname().
-else.
gethostname() ->
    erlang:error(notsup).
-endif.


%% ===========================================================================
%%
%% getnameinfo - Address-to-name translation in protocol-independent manner.
%%
%%

-spec getnameinfo(SockAddr) -> {ok, Info} | {error, Reason} when
      SockAddr :: socket:sockaddr(),
      Info     :: name_info(),
      Reason   :: term().

-dialyzer({no_return, getnameinfo/1}).

getnameinfo(SockAddr) ->
    getnameinfo(SockAddr, undefined).

-spec getnameinfo(SockAddr, Flags) -> {ok, Info} | {error, Reason} when
      SockAddr :: socket:sockaddr(),
      Flags    :: name_info_flags() | undefined,
      Info     :: name_info(),
      Reason   :: term().


-ifdef(USE_ESOCK).

getnameinfo(SockAddr, Flags)
  when is_map(SockAddr), is_list(Flags);
       is_map(SockAddr), Flags =:= undefined ->
    prim_net:getnameinfo(SockAddr, Flags).

-else.

-dialyzer({no_return, getnameinfo/2}).

getnameinfo(SockAddr, Flags)
  when is_map(SockAddr), is_list(Flags);
       is_map(SockAddr), Flags =:= undefined ->
    erlang:error(notsup).
-endif.


%% ===========================================================================
%%
%% getaddrinfo - Network address and service translation
%%
%% There is also a "hint" argument that we "at some point" should implement.

-spec getaddrinfo(Host) -> {ok, Info} | {error, Reason} when
      Host    :: string(),
      Info    :: [address_info()],
      Reason  :: term().

-dialyzer({no_return, getaddrinfo/1}).

getaddrinfo(Host) when is_list(Host) ->
    getaddrinfo(Host, undefined).


-spec getaddrinfo(Host, undefined) -> {ok, Info} | {error, Reason} when
      Host    :: string(),
      Info    :: [address_info()],
      Reason  :: term()
                 ; (undefined, Service) -> {ok, Info} | {error, Reason} when
      Service :: string(),
      Info    :: [address_info()],
      Reason  :: term()
                 ; (Host, Service) -> {ok, Info} | {error, Reason} when
      Host    :: string(),
      Service :: string(),
      Info    :: [address_info()],
      Reason  :: term().

-ifdef(USE_ESOCK).
getaddrinfo(Host, Service)
  when (is_list(Host) orelse (Host =:= undefined)) andalso
       (is_list(Service) orelse (Service =:= undefined)) andalso
       (not ((Service =:= undefined) andalso (Host =:= undefined))) ->
    prim_net:getaddrinfo(Host, Service).
-else.
getaddrinfo(Host, Service)
  when (is_list(Host) orelse (Host =:= undefined)) andalso
       (is_list(Service) orelse (Service =:= undefined)) andalso
       (not ((Service =:= undefined) andalso (Host =:= undefined))) ->
    erlang:error(notsup).
-endif.




%% ===========================================================================
%%
%% getifaddrs - Get interface addresses
%%

-spec getifaddrs() -> {ok, IfAddrs} | {error, Reason} when
      IfAddrs :: [ifaddrs()],
      Reason  :: term().

-ifdef(USE_ESOCK).
getifaddrs() ->
    getifaddrs(default).
-else.
getifaddrs() ->
    erlang:error(notsup).
-endif.


-spec getifaddrs(Filter) -> {ok, IfAddrs} | {error, Reason} when
      Filter    :: ifaddrs_filter(),
      IfAddrs   :: [ifaddrs()],
      Reason    :: term();
                (Namespace) -> {ok, IfAddrs} | {error, Reason} when
      Namespace :: file:filename_all(),
      IfAddrs   :: [ifaddrs()],
      Reason    :: term().

-ifdef(USE_ESOCK).
getifaddrs(Filter) when is_atom(Filter) orelse is_map(Filter) ->
    do_getifaddrs(getifaddrs_filter_map(Filter),
                  fun() -> prim_net:getifaddrs(#{}) end);
getifaddrs(Filter) when is_function(Filter, 1) ->
    do_getifaddrs(Filter, fun() -> prim_net:getifaddrs(#{}) end);
getifaddrs(Namespace) when is_list(Namespace) ->
    prim_net:getifaddrs(#{netns => Namespace}).
-else.
getifaddrs(Filter) when is_atom(Filter) orelse
                        is_map(Filter) orelse
                        is_function(Filter) ->
    erlang:error(notsup);
getifaddrs(Namespace) when is_list(Namespace) ->
    erlang:error(notsup).
-endif.


-spec getifaddrs(Filter, Namespace) -> {ok, IfAddrs} | {error, Reason} when
      Filter    :: ifaddrs_filter(),
      Namespace :: file:filename_all(),
      IfAddrs   :: [ifaddrs()],
      Reason    :: term().

-dialyzer({no_return, getifaddrs/2}).

getifaddrs(Filter, Namespace)
  when (is_atom(Filter) orelse is_map(Filter)) andalso is_list(Namespace) ->
    do_getifaddrs(getifaddrs_filter_map(Filter),
                  fun() -> getifaddrs(Namespace) end);
getifaddrs(Filter, Namespace)
  when is_function(Filter, 1) andalso is_list(Namespace) ->
    do_getifaddrs(Filter, fun() -> getifaddrs(Namespace) end).

-dialyzer({no_return, do_getifaddrs/2}).

do_getifaddrs(Filter, GetIfAddrs) ->
    case GetIfAddrs() of
        {ok, IfAddrs0} when is_function(Filter) ->
            {ok, lists:filtermap(Filter, IfAddrs0)};
        {ok, IfAddrs0} when is_map(Filter) ->
            FilterFun = fun(Elem) -> getifaddrs_filter(Filter, Elem) end,
            {ok, lists:filtermap(FilterFun, IfAddrs0)};
        {error, _} = ERROR ->
            ERROR
    end.

getifaddrs_filter_map(all) ->
    getifaddrs_filter_map_all();
getifaddrs_filter_map(default) ->
    getifaddrs_filter_map_default();
getifaddrs_filter_map(inet) ->
    getifaddrs_filter_map_inet();
getifaddrs_filter_map(inet6) ->
    getifaddrs_filter_map_inet6();
getifaddrs_filter_map(packet) ->
    getifaddrs_filter_map_packet();
getifaddrs_filter_map(FilterMap) when is_map(FilterMap) ->
    maps:merge(getifaddrs_filter_map_default(), FilterMap).

getifaddrs_filter_map_all() ->
    #{family => all, flags => any}.

getifaddrs_filter_map_default() ->
    #{family => default, flags => any}.

getifaddrs_filter_map_inet() ->
    #{family => inet, flags => any}.

getifaddrs_filter_map_inet6() ->
    #{family => inet6, flags => any}.

getifaddrs_filter_map_packet() ->
    #{family => packet, flags => any}.

-compile({nowarn_unused_function, getifaddrs_filter/2}).

getifaddrs_filter(#{family := FFamily, flags := FFlags},
                  #{addr := #{family := Family}, flags := Flags} = _Entry)
  when (FFamily =:= default) andalso
       ((Family =:= inet) orelse (Family =:= inet6)) ->
    getifaddrs_filter_flags(FFlags, Flags);
getifaddrs_filter(#{family := FFamily, flags := FFlags},
                  #{addr := #{family := Family}, flags := Flags} = _Entry)
  when (FFamily =:= inet) andalso (Family =:= inet) ->
    getifaddrs_filter_flags(FFlags, Flags);
getifaddrs_filter(#{family := FFamily, flags := FFlags},
                  #{addr := #{family := Family}, flags := Flags} = _Entry)
  when (FFamily =:= inet6) andalso (Family =:= inet6) ->
    getifaddrs_filter_flags(FFlags, Flags);
getifaddrs_filter(#{family := FFamily, flags := FFlags},
                  #{addr := #{family := Family}, flags := Flags} = _Entry)
  when (FFamily =:= packet) andalso (Family =:= packet) ->
    getifaddrs_filter_flags(FFlags, Flags);
getifaddrs_filter(#{family := FFamily, flags := FFlags},
                  #{flags := Flags} = _Entry)
  when (FFamily =:= all) ->
    getifaddrs_filter_flags(FFlags, Flags);
getifaddrs_filter(_Filter, _Entry) ->
    false.

-compile({nowarn_unused_function, getifaddrs_filter_flags/2}).

getifaddrs_filter_flags(any, _Flags) ->
    true;
getifaddrs_filter_flags(FilterFlags, Flags) ->
    [] =:= (FilterFlags -- Flags).


    
%% ===========================================================================
%%
%% if_name2index - Mappings between network interface names and indexes:
%%                 name -> idx
%%
%%

-spec if_name2index(Name) -> {ok, Idx} | {error, Reason} when
      Name   :: network_interface_name(),
      Idx    :: network_interface_index(),
      Reason :: term().

-ifdef(USE_ESOCK).
if_name2index(If) when is_list(If) ->
    prim_net:if_name2index(If).
-else.
if_name2index(If) when is_list(If) ->
    erlang:error(notsup).
-endif.



%% ===========================================================================
%%
%% if_index2name - Mappings between network interface index and names:
%%                 idx -> name
%%
%%

-spec if_index2name(Idx) -> {ok, Name} | {error, Reason} when
      Idx    :: network_interface_index(),
      Name   :: network_interface_name(),
      Reason :: term().

-ifdef(USE_ESOCK).
if_index2name(Idx) when is_integer(Idx) ->
    prim_net:if_index2name(Idx).
-else.
if_index2name(Idx) when is_integer(Idx) ->
    erlang:error(notsup).
-endif.



%% ===========================================================================
%%
%% if_names - Get network interface names and indexes
%%
%%

-spec if_names() -> Names | {error, Reason} when
      Names  :: [{Idx, If}],
      Idx    :: network_interface_index(),
      If     :: network_interface_name(),
      Reason :: term().

-ifdef(USE_ESOCK).
if_names() ->
    prim_net:if_names().
-else.
if_names() ->
    erlang:error(notsup).
-endif.


