%%%----------------------------------------------------------------------
%%% File    : ejabberd_auth_sql.erl
%%% Author  : Alexey Shchepin <alexey@process-one.net>
%%% Purpose : Authentication via ODBC
%%% Created : 12 Dec 2004 by Alexey Shchepin <alexey@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2024   ProcessOne
%%%
%%% This program 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 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program 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 this program; if not, write to the Free Software Foundation, Inc.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%----------------------------------------------------------------------

-module(ejabberd_auth_sql).


-author('alexey@process-one.net').

-behaviour(ejabberd_auth).

-export([start/1, stop/1, set_password/3, try_register/3,
	 get_users/2, count_users/2, get_password/2,
	 remove_user/2, store_type/1, plain_password_required/1,
	 export/1, which_users_exists/2]).
-export([sql_schemas/0]).

-include_lib("xmpp/include/scram.hrl").
-include("logger.hrl").
-include("ejabberd_sql_pt.hrl").
-include("ejabberd_auth.hrl").

%%%----------------------------------------------------------------------
%%% API
%%%----------------------------------------------------------------------
start(Host) ->
    ejabberd_sql_schema:update_schema(Host, ?MODULE, sql_schemas()),
    ok.

sql_schemas() ->
    [#sql_schema{
        version = 1,
        tables =
            [#sql_table{
                name = <<"users">>,
                columns =
                    [#sql_column{name = <<"username">>, type = text},
                     #sql_column{name = <<"server_host">>, type = text},
                     #sql_column{name = <<"password">>, type = text},
                     #sql_column{name = <<"serverkey">>, type = {text, 128},
                                 default = true},
                     #sql_column{name = <<"salt">>, type = {text, 128},
                                 default = true},
                     #sql_column{name = <<"iterationcount">>, type = integer,
                                 default = true},
                     #sql_column{name = <<"created_at">>, type = timestamp,
                                 default = true}],
                indices = [#sql_index{
                              columns = [<<"server_host">>, <<"username">>],
                              unique = true}]}]}].

stop(_Host) -> ok.

plain_password_required(Server) ->
    store_type(Server) == scram.

store_type(Server) ->
    ejabberd_auth:password_format(Server).

set_password(User, Server, Password) ->
    F =
    fun() ->
	case Password of
	    #scram{hash = Hash, storedkey = SK, serverkey = SEK,
		   salt = Salt, iterationcount = IC} ->
		SK2 = scram_hash_encode(Hash, SK),
		set_password_scram_t(
		    User, Server,
		    SK2, SEK, Salt, IC);
	    _ ->
		set_password_t(User, Server, Password)
	end
    end,
    case ejabberd_sql:sql_transaction(Server, F) of
	{atomic, _} ->
	    {cache, {ok, Password}};
	{aborted, _} ->
	    {nocache, {error, db_failure}}
    end.

try_register(User, Server, Password) ->
    Res =
    case Password of
	#scram{hash = Hash, storedkey = SK, serverkey = SEK,
	       salt = Salt, iterationcount = IC} ->
	    SK2 = scram_hash_encode(Hash, SK),
	    add_user_scram(
		Server, User,
		SK2, SEK, Salt, IC);
	_ ->
	    add_user(Server, User, Password)
    end,
    case Res of
	{updated, 1} -> {cache, {ok, Password}};
	_ -> {nocache, {error, exists}}
    end.

get_users(Server, Opts) ->
    case list_users(Server, Opts) of
	{selected, Res} ->
	    [{U, Server} || {U} <- Res];
	_ -> []
    end.

count_users(Server, Opts) ->
    case users_number(Server, Opts) of
	{selected, [{Res}]} ->
	    Res;
	_Other -> 0
    end.

get_password(User, Server) ->
    case get_password_scram(Server, User) of
	{selected, [{Password, <<>>, <<>>, 0}]} ->
	    {cache, {ok, Password}};
	{selected, [{StoredKey, ServerKey, Salt, IterationCount}]} ->
	    {Hash, SK} = case StoredKey of
			     <<"sha256:", Rest/binary>> -> {sha256, Rest};
			     <<"sha512:", Rest/binary>> -> {sha512, Rest};
			     Other -> {sha, Other}
			 end,
	    {cache, {ok, #scram{storedkey = SK,
				serverkey = ServerKey,
				salt = Salt,
				hash = Hash,
				iterationcount = IterationCount}}};
	{selected, []} ->
	    {cache, error};
	_ ->
	    {nocache, error}
    end.

remove_user(User, Server) ->
    case del_user(Server, User) of
	{updated, _} ->
	    ok;
	_ ->
	    {error, db_failure}
    end.

scram_hash_encode(Hash, StoreKey) ->
    case Hash of
	sha -> StoreKey;
	sha256 -> <<"sha256:", StoreKey/binary>>;
	sha512 -> <<"sha512:", StoreKey/binary>>
    end.

set_password_scram_t(LUser, LServer,
                     StoredKey, ServerKey, Salt, IterationCount) ->
    ?SQL_UPSERT_T(
       "users",
       ["!username=%(LUser)s",
        "!server_host=%(LServer)s",
        "password=%(StoredKey)s",
        "serverkey=%(ServerKey)s",
        "salt=%(Salt)s",
        "iterationcount=%(IterationCount)d"]).

set_password_t(LUser, LServer, Password) ->
    ?SQL_UPSERT_T(
       "users",
       ["!username=%(LUser)s",
        "!server_host=%(LServer)s",
	"password=%(Password)s",
	"serverkey=''",
	"salt=''",
	"iterationcount=0"]).

get_password_scram(LServer, LUser) ->
    ejabberd_sql:sql_query(
      LServer,
      ?SQL("select @(password)s, @(serverkey)s, @(salt)s, @(iterationcount)d"
           " from users"
           " where username=%(LUser)s and %(LServer)H")).

add_user_scram(LServer, LUser,
               StoredKey, ServerKey, Salt, IterationCount) ->
    ejabberd_sql:sql_query(
      LServer,
      ?SQL_INSERT(
         "users",
         ["username=%(LUser)s",
          "server_host=%(LServer)s",
          "password=%(StoredKey)s",
          "serverkey=%(ServerKey)s",
          "salt=%(Salt)s",
          "iterationcount=%(IterationCount)d"])).

add_user(LServer, LUser, Password) ->
    ejabberd_sql:sql_query(
      LServer,
      ?SQL_INSERT(
         "users",
         ["username=%(LUser)s",
          "server_host=%(LServer)s",
          "password=%(Password)s"])).

del_user(LServer, LUser) ->
    ejabberd_sql:sql_query(
      LServer,
      ?SQL("delete from users where username=%(LUser)s and %(LServer)H")).

list_users(LServer, []) ->
    ejabberd_sql:sql_query(
      LServer,
      ?SQL("select @(username)s from users where %(LServer)H"));
list_users(LServer, [{from, Start}, {to, End}])
    when is_integer(Start) and is_integer(End) ->
    list_users(LServer,
	       [{limit, End - Start + 1}, {offset, Start - 1}]);
list_users(LServer,
	   [{prefix, Prefix}, {from, Start}, {to, End}])
    when is_binary(Prefix) and is_integer(Start) and
	   is_integer(End) ->
    list_users(LServer,
	       [{prefix, Prefix}, {limit, End - Start + 1},
		{offset, Start - 1}]);
list_users(LServer, [{limit, Limit}, {offset, Offset}])
    when is_integer(Limit) and is_integer(Offset) ->
    ejabberd_sql:sql_query(
      LServer,
      ?SQL("select @(username)s from users "
           "where %(LServer)H "
           "order by username "
           "limit %(Limit)d offset %(Offset)d"));
list_users(LServer,
	   [{prefix, Prefix}, {limit, Limit}, {offset, Offset}])
    when is_binary(Prefix) and is_integer(Limit) and
	   is_integer(Offset) ->
    SPrefix = ejabberd_sql:escape_like_arg(Prefix),
    SPrefix2 = <<SPrefix/binary, $%>>,
    ejabberd_sql:sql_query(
      LServer,
      ?SQL("select @(username)s from users "
           "where username like %(SPrefix2)s %ESCAPE and %(LServer)H "
           "order by username "
           "limit %(Limit)d offset %(Offset)d")).

users_number(LServer) ->
    ejabberd_sql:sql_query(
      LServer,
      fun(pgsql, _) ->
              case
                  ejabberd_option:pgsql_users_number_estimate(LServer) of
                  true ->
                      ejabberd_sql:sql_query_t(
                        ?SQL("select @(reltuples :: bigint)d from pg_class"
                             " where oid = 'users'::regclass::oid"));
                  _ ->
                      ejabberd_sql:sql_query_t(
                        ?SQL("select @(count(*))d from users where %(LServer)H"))
	  end;
         (_Type, _) ->
              ejabberd_sql:sql_query_t(
                ?SQL("select @(count(*))d from users where %(LServer)H"))
      end).

users_number(LServer, [{prefix, Prefix}])
    when is_binary(Prefix) ->
    SPrefix = ejabberd_sql:escape_like_arg(Prefix),
    SPrefix2 = <<SPrefix/binary, $%>>,
    ejabberd_sql:sql_query(
      LServer,
      ?SQL("select @(count(*))d from users "
           "where username like %(SPrefix2)s %ESCAPE and %(LServer)H"));
users_number(LServer, []) ->
    users_number(LServer).

which_users_exists(LServer, LUsers) when length(LUsers) =< 100 ->
    try ejabberd_sql:sql_query(
        LServer,
        ?SQL("select @(username)s from users where username in %(LUsers)ls")) of
        {selected, Matching} ->
            [U || {U} <- Matching];
        {error, _} = E ->
            E
    catch _:B ->
        {error, B}
    end;
which_users_exists(LServer, LUsers) ->
    {First, Rest} = lists:split(100, LUsers),
    case which_users_exists(LServer, First) of
        {error, _} = E ->
            E;
        V ->
            case which_users_exists(LServer, Rest) of
                {error, _} = E2 ->
                    E2;
                V2 ->
                    V ++ V2
            end
    end.

export(_Server) ->
    [{passwd,
      fun(Host, #passwd{us = {LUser, LServer}, password = Password})
            when LServer == Host,
                 is_binary(Password) ->
              [?SQL("delete from users where username=%(LUser)s and %(LServer)H;"),
               ?SQL_INSERT(
                  "users",
                  ["username=%(LUser)s",
                   "server_host=%(LServer)s",
                   "password=%(Password)s"])];
         (Host, {passwd, {LUser, LServer},
                         {scram, StoredKey1, ServerKey, Salt, IterationCount}})
            when LServer == Host ->
              Hash = sha,
              StoredKey = scram_hash_encode(Hash, StoredKey1),
              [?SQL("delete from users where username=%(LUser)s and %(LServer)H;"),
               ?SQL_INSERT(
                  "users",
                  ["username=%(LUser)s",
                   "server_host=%(LServer)s",
                   "password=%(StoredKey)s",
                   "serverkey=%(ServerKey)s",
                   "salt=%(Salt)s",
                   "iterationcount=%(IterationCount)d"])];
         (Host, #passwd{us = {LUser, LServer}, password = #scram{} = Scram})
            when LServer == Host ->
	      StoredKey = scram_hash_encode(Scram#scram.hash, Scram#scram.storedkey),
              ServerKey = Scram#scram.serverkey,
              Salt = Scram#scram.salt,
              IterationCount = Scram#scram.iterationcount,
              [?SQL("delete from users where username=%(LUser)s and %(LServer)H;"),
               ?SQL_INSERT(
                  "users",
                  ["username=%(LUser)s",
                   "server_host=%(LServer)s",
                   "password=%(StoredKey)s",
                   "serverkey=%(ServerKey)s",
                   "salt=%(Salt)s",
                   "iterationcount=%(IterationCount)d"])];
         (_Host, _R) ->
              []
      end}].