# --
# Copyright (C) 2001-2021 OTRS AG, https://otrs.com/
# Copyright (C) 2021 Znuny GmbH, https://znuny.org/
# --
# This software comes with ABSOLUTELY NO WARRANTY. For details, see
# the enclosed file COPYING for license information (GPL). If you
# did not receive this file, see https://www.gnu.org/licenses/gpl-3.0.txt.
# --

package Kernel::System::User;

use strict;
use warnings;

use Crypt::PasswdMD5 qw(unix_md5_crypt apache_md5_crypt);
use Digest::SHA;

our @ObjectDependencies = (
    'Kernel::Config',
    'Kernel::System::Cache',
    'Kernel::System::CheckItem',
    'Kernel::System::DB',
    'Kernel::System::DateTime',
    'Kernel::System::Encode',
    'Kernel::System::Log',
    'Kernel::System::Main',
    'Kernel::System::SearchProfile',
    'Kernel::System::Time',
    'Kernel::System::Valid',
);

=head1 NAME

Kernel::System::User - user lib

=head1 DESCRIPTION

All user functions. E. g. to add and updated user and other functions.

=head1 PUBLIC INTERFACE

=head2 new()

Don't use the constructor directly, use the ObjectManager instead:

    my $UserObject = $Kernel::OM->Get('Kernel::System::User');

=cut

sub new {
    my ( $Type, %Param ) = @_;

    # allocate new hash for object
    my $Self = {};
    bless( $Self, $Type );

    # get config object
    my $ConfigObject = $Kernel::OM->Get('Kernel::Config');

    # get user table
    $Self->{UserTable}       = $ConfigObject->Get('DatabaseUserTable')       || 'user';
    $Self->{UserTableUserID} = $ConfigObject->Get('DatabaseUserTableUserID') || 'id';
    $Self->{UserTableUserPW} = $ConfigObject->Get('DatabaseUserTableUserPW') || 'pw';
    $Self->{UserTableUser}   = $ConfigObject->Get('DatabaseUserTableUser')   || 'login';

    $Self->{CacheType} = 'User';
    $Self->{CacheTTL}  = 60 * 60 * 24 * 20;

    # set lower if database is case sensitive
    $Self->{Lower} = '';
    if ( $Kernel::OM->Get('Kernel::System::DB')->GetDatabaseFunction('CaseSensitive') ) {
        $Self->{Lower} = 'LOWER';
    }

    return $Self;
}

=head2 GetUserData()

get user data (UserLogin, UserFirstname, UserLastname, UserEmail, ...)

    my %User = $UserObject->GetUserData(
        UserID => 123,
    );

    or

    my %User = $UserObject->GetUserData(
        User          => 'franz',
        Valid         => 1,       # not required -> 0|1 (default 0)
                                  # returns only data if user is valid
        NoOutOfOffice => 1,       # not required -> 0|1 (default 0)
                                  # returns data without out of office infos
    );

=cut

sub GetUserData {
    my ( $Self, %Param ) = @_;

    # check needed stuff
    if ( !$Param{User} && !$Param{UserID} ) {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => 'Need User or UserID!',
        );
        return;
    }

    # get config object
    my $ConfigObject = $Kernel::OM->Get('Kernel::Config');

    # get configuration for the full name order
    my $FirstnameLastNameOrder = $ConfigObject->Get('FirstnameLastnameOrder') || 0;

    # check if result is cached
    if ( $Param{Valid} ) {
        $Param{Valid} = 1;
    }
    else {
        $Param{Valid} = 0;
    }
    if ( $Param{NoOutOfOffice} ) {
        $Param{NoOutOfOffice} = 1;
    }
    else {
        $Param{NoOutOfOffice} = 0;
    }

    my $CacheKey;
    if ( $Param{User} ) {
        $CacheKey = join '::', 'GetUserData', 'User',
            $Param{User},
            $Param{Valid},
            $FirstnameLastNameOrder,
            $Param{NoOutOfOffice};
    }
    else {
        $CacheKey = join '::', 'GetUserData', 'UserID',
            $Param{UserID},
            $Param{Valid},
            $FirstnameLastNameOrder,
            $Param{NoOutOfOffice};
    }

    # check cache
    my $Cache = $Kernel::OM->Get('Kernel::System::Cache')->Get(
        Type => $Self->{CacheType},
        Key  => $CacheKey,
    );
    return %{$Cache} if $Cache;

    # get initial data
    my @Bind;
    my $SQL = "SELECT $Self->{UserTableUserID}, $Self->{UserTableUser}, "
        . " title, first_name, last_name, $Self->{UserTableUserPW}, valid_id, "
        . " create_time, change_time FROM $Self->{UserTable} WHERE ";

    if ( $Param{User} ) {
        my $User = lc $Param{User};
        $SQL .= " $Self->{Lower}($Self->{UserTableUser}) = ?";
        push @Bind, \$User;
    }
    else {
        $SQL .= " $Self->{UserTableUserID} = ?";
        push @Bind, \$Param{UserID};
    }

    # get database object
    my $DBObject = $Kernel::OM->Get('Kernel::System::DB');

    return if !$DBObject->Prepare(
        SQL   => $SQL,
        Bind  => \@Bind,
        Limit => 1,
    );

    my %Data;
    while ( my @Row = $DBObject->FetchrowArray() ) {
        $Data{UserID}        = $Row[0];
        $Data{UserLogin}     = $Row[1];
        $Data{UserTitle}     = $Row[2];
        $Data{UserFirstname} = $Row[3];
        $Data{UserLastname}  = $Row[4];
        $Data{UserPw}        = $Row[5];
        $Data{ValidID}       = $Row[6];
        $Data{CreateTime}    = $Row[7];
        $Data{ChangeTime}    = $Row[8];
    }

    # check data
    if ( !$Data{UserID} ) {
        if ( $Param{User} ) {
            $Kernel::OM->Get('Kernel::System::Log')->Log(
                Priority => 'notice',
                Message  => "No UserData for user: '$Param{User}'.",
            );
            return;
        }
        else {
            $Kernel::OM->Get('Kernel::System::Log')->Log(
                Priority => 'notice',
                Message  => "No UserData for user id: '$Param{UserID}'.",
            );
            return;
        }
    }

    # Store CacheTTL locally so that we can reduce it for users that are out of office.
    my $CacheTTL = $Self->{CacheTTL};

    # check valid, return if there is locked for valid users
    if ( $Param{Valid} ) {

        my $Hit = 0;

        for ( $Kernel::OM->Get('Kernel::System::Valid')->ValidIDsGet() ) {
            if ( $_ eq $Data{ValidID} ) {
                $Hit = 1;
            }
        }

        if ( !$Hit ) {

            # set cache
            $Kernel::OM->Get('Kernel::System::Cache')->Set(
                Type  => $Self->{CacheType},
                TTL   => $CacheTTL,
                Key   => $CacheKey,
                Value => {},
            );
            return;
        }
    }

    # generate the full name and save it in the hash
    my $UserFullname = $Self->_UserFullname(
        %Data,
        NameOrder => $FirstnameLastNameOrder,
    );

    # save the generated fullname in the hash.
    $Data{UserFullname} = $UserFullname;

    # get preferences
    my %Preferences = $Self->GetPreferences( UserID => $Data{UserID} );

    my $DateTimeObject = $Kernel::OM->Create('Kernel::System::DateTime');

    # add last login timestamp
    if ( $Preferences{UserLastLogin} ) {

        my $UserLastLoginTimeObj = $Kernel::OM->Create(
            'Kernel::System::DateTime',
            ObjectParams => {
                Epoch => $Preferences{UserLastLogin}
            }
        );

        $Preferences{UserLastLoginTimestamp} = $UserLastLoginTimeObj->ToString();
    }

    # check compat stuff
    if ( !$Preferences{UserEmail} ) {
        $Preferences{UserEmail} = $Data{UserLogin};
    }

    # out of office check
    if ( !$Param{NoOutOfOffice} ) {
        my %AvailableInformationMessage;

        for my $InformationName (qw(LoggedIn LoggedOut)) {
            $AvailableInformationMessage{$InformationName} = $ConfigObject->Get(
                'OutOfOffice::DisplayAgent' . $InformationName . 'Message'
            );
        }

        if (%AvailableInformationMessage) {
            my $SessionTable         = $ConfigObject->Get('SessionTable')   // 'sessions';
            my $MaxSessionTime       = $ConfigObject->Get('SessionMaxTime') // 57600;
            my $SystemTime           = $Kernel::OM->Get('Kernel::System::Time')->SystemTime();
            my $LastValidSessionTime = $SystemTime - $MaxSessionTime;

            return if !$DBObject->Prepare(
                SQL => "
                    SELECT s2.data_value
                    FROM   $SessionTable s1, $SessionTable s2
                    WHERE  s1.data_key = 'UserEmail'
                        AND s1.data_value LIKE ?
                        AND s1.session_id = s2.session_id
                        AND s2.data_key = 'UserLastRequest'
                ",
                Bind => [
                    \$Preferences{UserEmail},
                ],
            );

            my @UserLastRequests;
            while ( my @Row = $DBObject->FetchrowArray() ) {
                push @UserLastRequests, $Row[0];
            }
            @UserLastRequests = reverse sort @UserLastRequests;

            my %AvailableInformation = (
                LoggedIn  => 0,
                LoggedOut => 0,
            );

            if (
                $UserLastRequests[0]
                && $UserLastRequests[0] > $LastValidSessionTime
                )
            {
                $AvailableInformation{LoggedIn} = 1;
            }

            if ( !$AvailableInformation{LoggedIn} ) {
                $AvailableInformation{LoggedOut} = 1;
                $AvailableInformation{LoggedIn}  = 0;
            }

            INFORMATIONNAME:
            for my $InformationName (qw(LoggedIn LoggedOut)) {
                next INFORMATIONNAME if !$AvailableInformationMessage{$InformationName};
                next INFORMATIONNAME if !$AvailableInformation{$InformationName};

                $Preferences{LoggedStatusMessage} = $AvailableInformationMessage{$InformationName} . ' ';
                $Data{UserFullname} .= ' ' . $AvailableInformationMessage{$InformationName} . ' ';
            }
        }

        if ( $Preferences{OutOfOffice} ) {

            my $CurrentTimeObject = $Kernel::OM->Create('Kernel::System::DateTime');
            my $CreateDTObject    = sub {
                my %Param = @_;

                return $Kernel::OM->Create(
                    'Kernel::System::DateTime',
                    ObjectParams => {
                        String => sprintf(
                            '%d-%02d-%02d %s',
                            $Param{Year},
                            $Param{Month},
                            $Param{Day},
                            $Param{Time}
                        ),
                    },
                );
            };

            my $TimeStartObj = $CreateDTObject->(
                Year  => $Preferences{OutOfOfficeStartYear},
                Month => $Preferences{OutOfOfficeStartMonth},
                Day   => $Preferences{OutOfOfficeStartDay},
                Time  => '00:00:00',
            );

            my $TimeEndObj = $CreateDTObject->(
                Year  => $Preferences{OutOfOfficeEndYear},
                Month => $Preferences{OutOfOfficeEndMonth},
                Day   => $Preferences{OutOfOfficeEndDay},
                Time  => '23:59:59',
            );

            $Preferences{OutOfOfficeDaysRemaining}
                = int( ( $TimeEndObj->ToEpoch() - $CurrentTimeObject->ToEpoch() ) / 60 / 60 / 24 );

            if ( $TimeStartObj < $CurrentTimeObject && $TimeEndObj > $CurrentTimeObject ) {
                my $OutOfficeMessage = $ConfigObject->Get('OutOfOffice::DisplayAgentOutOfOfficeMessage')
                    // '*** out of office until ###EndYear###-###EndMonth###-###EndDay###/###DaysRemaining### d ***';

                for my $CurrentAttribute (qw(StartYear StartMonth StartDay EndYear EndMonth EndDay DaysRemaining )) {
                    my $ReplaceValue = $Preferences{ 'OutOfOffice' . $CurrentAttribute } // '';
                    $OutOfficeMessage =~ s{\#\#\#$CurrentAttribute\#\#\#}{$ReplaceValue}g;
                }

                $Preferences{OutOfOfficeMessage} .= $OutOfficeMessage;
                $Data{UserFullname}              .= ' ' . $OutOfficeMessage;
            }

            # Reduce CacheTTL to one hour for users that are out of office to make sure the cache expires timely
            # even if there is no update action.
            $CacheTTL = 60 * 60 * 1;
        }
    }

    # merge hash
    %Data = ( %Data, %Preferences );

    # add preferences defaults
    my $Config = $ConfigObject->Get('PreferencesGroups');
    if ( $Config && ref $Config eq 'HASH' ) {

        KEY:
        for my $Key ( sort keys %{$Config} ) {

            next KEY if !defined $Config->{$Key}->{DataSelected};

            # check if data is defined
            next KEY if defined $Data{ $Config->{$Key}->{PrefKey} };

            # set default data
            $Data{ $Config->{$Key}->{PrefKey} } = $Config->{$Key}->{DataSelected};
        }
    }

    # set cache
    $Kernel::OM->Get('Kernel::System::Cache')->Set(
        Type  => $Self->{CacheType},
        TTL   => $CacheTTL,
        Key   => $CacheKey,
        Value => \%Data,
    );

    return %Data;
}

=head2 UserAdd()

to add new users

    my $UserID = $UserObject->UserAdd(
        UserFirstname => 'Huber',
        UserLastname  => 'Manfred',
        UserLogin     => 'mhuber',
        UserPw        => 'some-pass', # not required
        UserEmail     => 'email@example.com',
        UserMobile    => '1234567890', # not required
        ValidID       => 1,
        ChangeUserID  => 123,
    );

=cut

sub UserAdd {
    my ( $Self, %Param ) = @_;

    # check needed stuff
    for my $Needed (qw(UserFirstname UserLastname UserLogin UserEmail ValidID ChangeUserID)) {
        if ( !$Param{$Needed} ) {
            $Kernel::OM->Get('Kernel::System::Log')->Log(
                Priority => 'error',
                Message  => "Need $Needed!",
            );
            return;
        }
    }

    # check if a user with this login (username) already exits
    if ( $Self->UserLoginExistsCheck( UserLogin => $Param{UserLogin} ) ) {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => "A user with the username '$Param{UserLogin}' already exists.",
        );
        return;
    }

    # check email address
    if (
        $Param{UserEmail}
        && !$Kernel::OM->Get('Kernel::System::CheckItem')->CheckEmail( Address => $Param{UserEmail} )
        && grep { $_ eq $Param{ValidID} } $Kernel::OM->Get('Kernel::System::Valid')->ValidIDsGet()
        )
    {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => "Email address ($Param{UserEmail}) not valid ("
                . $Kernel::OM->Get('Kernel::System::CheckItem')->CheckError() . ")!",
        );
        return;
    }

    # check password
    if ( !$Param{UserPw} ) {
        $Param{UserPw} = $Self->GenerateRandomPassword();
    }

    # get database object
    my $DBObject = $Kernel::OM->Get('Kernel::System::DB');

    # Don't store the user's password in plaintext initially. It will be stored in a
    #   hashed version later with SetPassword().
    my $RandomPassword = $Self->GenerateRandomPassword();

    # sql
    return if !$DBObject->Do(
        SQL => "INSERT INTO $Self->{UserTable} "
            . "(title, first_name, last_name, "
            . " $Self->{UserTableUser}, $Self->{UserTableUserPW}, "
            . " valid_id, create_time, create_by, change_time, change_by)"
            . " VALUES "
            . " (?, ?, ?, ?, ?, ?, current_timestamp, ?, current_timestamp, ?)",
        Bind => [
            \$Param{UserTitle},    \$Param{UserFirstname}, \$Param{UserLastname},
            \$Param{UserLogin},    \$RandomPassword,       \$Param{ValidID},
            \$Param{ChangeUserID}, \$Param{ChangeUserID},
        ],
    );

    # get new user id
    my $UserLogin = lc $Param{UserLogin};
    return if !$DBObject->Prepare(
        SQL => "SELECT $Self->{UserTableUserID} FROM $Self->{UserTable} "
            . " WHERE $Self->{Lower}($Self->{UserTableUser}) = ?",
        Bind  => [ \$UserLogin ],
        Limit => 1,
    );

    # fetch the result
    my $UserID;
    while ( my @Row = $DBObject->FetchrowArray() ) {
        $UserID = $Row[0];
    }

    # check if user exists
    if ( !$UserID ) {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'notice',
            Message  => "Unable to create User: '$Param{UserLogin}' ($Param{ChangeUserID})!",
        );
        return;
    }

    # Set configured default preferences
    my $DefaultPreferences = $Kernel::OM->Get('Kernel::Config')->Get('User::DefaultPreferences') // {};
    for my $Preference ( sort keys %{$DefaultPreferences} ) {
        my $Value = $DefaultPreferences->{$Preference};

        $Self->SetPreferences(
            UserID => $UserID,
            Key    => $Preference,
            Value  => $Value,
        );
    }

    # log notice
    $Kernel::OM->Get('Kernel::System::Log')->Log(
        Priority => 'notice',
        Message  =>
            "User: '$Param{UserLogin}' ID: '$UserID' created successfully ($Param{ChangeUserID})!",
    );

    # set password
    $Self->SetPassword(
        UserLogin => $Param{UserLogin},
        PW        => $Param{UserPw}
    );

    my @UserPreferences = grep { $_ =~ m{^User}xsi } sort keys %Param;

    USERPREFERENCE:
    for my $UserPreference (@UserPreferences) {

        # UserEmail is required.
        next USERPREFERENCE if $UserPreference eq 'UserEmail' && !$Param{UserEmail};

        # Set user preferences.
        # Native user data will not be overwritten (handled by SetPreferences()).
        $Self->SetPreferences(
            UserID => $UserID,
            Key    => $UserPreference,
            Value  => $Param{$UserPreference} || '',
        );
    }

    # delete cache
    $Kernel::OM->Get('Kernel::System::Cache')->CleanUp(
        Type => $Self->{CacheType},
    );

    return $UserID;
}

=head2 UserUpdate()

to update users

    $UserObject->UserUpdate(
        UserID        => 4321,
        UserFirstname => 'Huber',
        UserLastname  => 'Manfred',
        UserLogin     => 'mhuber',
        UserPw        => 'some-pass', # not required
        UserEmail     => 'email@example.com',
        UserMobile    => '1234567890', # not required
        ValidID       => 1,
        ChangeUserID  => 123,
    );

=cut

sub UserUpdate {
    my ( $Self, %Param ) = @_;

    # check needed stuff
    for my $Needed (qw(UserID UserFirstname UserLastname UserLogin ValidID ChangeUserID)) {
        if ( !$Param{$Needed} ) {
            $Kernel::OM->Get('Kernel::System::Log')->Log(
                Priority => 'error',
                Message  => "Need $Needed!",
            );
            return;
        }
    }

    # store old user login for later use
    my $OldUserLogin = $Self->UserLookup(
        UserID => $Param{UserID},
    );

    # check if a user with this login (username) already exists
    if (
        $Self->UserLoginExistsCheck(
            UserLogin => $Param{UserLogin},
            UserID    => $Param{UserID}
        )
        )
    {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => "A user with the username '$Param{UserLogin}' already exists.",
        );
        return;
    }

    # check email address
    if (
        $Param{UserEmail}
        && !$Kernel::OM->Get('Kernel::System::CheckItem')->CheckEmail( Address => $Param{UserEmail} )
        && grep { $_ eq $Param{ValidID} } $Kernel::OM->Get('Kernel::System::Valid')->ValidIDsGet()
        )
    {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => "Email address ($Param{UserEmail}) not valid ("
                . $Kernel::OM->Get('Kernel::System::CheckItem')->CheckError() . ")!",
        );
        return;
    }

    # update db
    return if !$Kernel::OM->Get('Kernel::System::DB')->Do(
        SQL => "UPDATE $Self->{UserTable} SET title = ?, first_name = ?, last_name = ?, "
            . " $Self->{UserTableUser} = ?, valid_id = ?, "
            . " change_time = current_timestamp, change_by = ? "
            . " WHERE $Self->{UserTableUserID} = ?",
        Bind => [
            \$Param{UserTitle}, \$Param{UserFirstname}, \$Param{UserLastname},
            \$Param{UserLogin}, \$Param{ValidID}, \$Param{ChangeUserID}, \$Param{UserID},
        ],
    );

    # check pw
    if ( $Param{UserPw} ) {
        $Self->SetPassword(
            UserLogin => $Param{UserLogin},
            PW        => $Param{UserPw}
        );
    }

    my @UserPreferences = grep { $_ =~ m{^User}xsi } sort keys %Param;

    USERPREFERENCE:
    for my $UserPreference (@UserPreferences) {

        # UserEmail is required.
        next USERPREFERENCE if $UserPreference eq 'UserEmail' && !$Param{UserEmail};

        # Set user preferences.
        # Native user data will not be overwritten (handled by SetPreferences()).
        $Self->SetPreferences(
            UserID => $Param{UserID},
            Key    => $UserPreference,
            Value  => $Param{$UserPreference} || '',
        );
    }

    # update search profiles if the UserLogin changed
    if ( lc $OldUserLogin ne lc $Param{UserLogin} ) {
        $Kernel::OM->Get('Kernel::System::SearchProfile')->SearchProfileUpdateUserLogin(
            Base         => 'TicketSearch',
            UserLogin    => $OldUserLogin,
            NewUserLogin => $Param{UserLogin},
        );
    }

    $Self->_UserCacheClear( UserID => $Param{UserID} );

    my $CacheObject            = $Kernel::OM->Get('Kernel::System::Cache');
    my $SystemPermissionConfig = $Kernel::OM->Get('Kernel::Config')->Get('System::Permission') || [];

    for my $Type ( @{$SystemPermissionConfig}, 'rw' ) {

        $CacheObject->Delete(
            Type => 'GroupPermissionUserGet',
            Key  => 'PermissionUserGet::' . $Param{UserID} . '::' . $Type,
        );
    }

    $CacheObject->CleanUp(
        Type => 'GroupPermissionGroupGet',
    );

    return 1;
}

=head2 UserSearch()

to search users

    my %List = $UserObject->UserSearch(
        Search => '*some*', # also 'hans+huber' possible
        Valid  => 1, # not required
    );

    my %List = $UserObject->UserSearch(
        UserLogin => '*some*',
        Limit     => 50,
        Valid     => 1, # not required
    );

    my %List = $UserObject->UserSearch(
        PostMasterSearch => 'email@example.com',
        Valid            => 1, # not required
    );

Returns hash of UserID, Login pairs:

    my %List = (
        1 => 'root@locahost',
        4 => 'admin',
        9 => 'joe',
    );

For PostMasterSearch, it returns hash of UserID, Email pairs:

    my %List = (
        4 => 'john@example.com',
        9 => 'joe@example.com',
    );

=cut

sub UserSearch {
    my ( $Self, %Param ) = @_;

    my %Users;
    my $Valid = $Param{Valid} // 1;

    # check needed stuff
    if ( !$Param{Search} && !$Param{UserLogin} && !$Param{PostMasterSearch} ) {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => 'Need Search, UserLogin or PostMasterSearch!',
        );
        return;
    }

    # get database object
    my $DBObject = $Kernel::OM->Get('Kernel::System::DB');

    # get like escape string needed for some databases (e.g. oracle)
    my $LikeEscapeString = $DBObject->GetDatabaseFunction('LikeEscapeString');

    # build SQL string
    my $SQL = "SELECT $Self->{UserTableUserID}, login
                   FROM $Self->{UserTable} WHERE ";
    my @Bind;

    if ( $Param{Search} ) {

        my %QueryCondition = $DBObject->QueryCondition(
            Key      => [qw(login first_name last_name)],
            Value    => $Param{Search},
            BindMode => 1,
        );
        $SQL .= $QueryCondition{SQL} . ' ';
        push @Bind, @{ $QueryCondition{Values} };
    }
    elsif ( $Param{PostMasterSearch} ) {

        my %UserID = $Self->SearchPreferences(
            Key   => 'UserEmail',
            Value => $Param{PostMasterSearch},
        );

        for my $UserID ( sort keys %UserID ) {
            my %User = $Self->GetUserData(
                UserID => $UserID,
                Valid  => $Param{Valid},
            );
            if (%User) {
                return %UserID;
            }
        }

        return;
    }
    elsif ( $Param{UserLogin} ) {

        my $UserLogin = lc $Param{UserLogin};
        $SQL .= " $Self->{Lower}($Self->{UserTableUser}) LIKE ? $LikeEscapeString";
        $UserLogin =~ s/\*/%/g;
        $UserLogin = $DBObject->Quote( $UserLogin, 'Like' );
        push @Bind, \$UserLogin;
    }

    # add valid option
    if ($Valid) {
        $SQL .= "AND valid_id IN ("
            . join( ', ', $Kernel::OM->Get('Kernel::System::Valid')->ValidIDsGet() ) . ")";
    }

    # get data
    return if !$DBObject->Prepare(
        SQL   => $SQL,
        Bind  => \@Bind,
        Limit => $Self->{UserSearchListLimit} || $Param{Limit},
    );

    # fetch the result
    while ( my @Row = $DBObject->FetchrowArray() ) {
        $Users{ $Row[0] } = $Row[1];
    }

    return %Users;
}

=head2 SetPassword()

to set users passwords

    $UserObject->SetPassword(
        UserLogin => 'some-login',
        PW        => 'some-new-password'
    );

=cut

sub SetPassword {
    my ( $Self, %Param ) = @_;

    # check needed stuff
    if ( !$Param{UserLogin} ) {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => 'Need UserLogin!'
        );
        return;
    }

    # get old user data
    my %User = $Self->GetUserData( User => $Param{UserLogin} );
    if ( !$User{UserLogin} ) {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => 'No such User!',
        );
        return;
    }

    my $Pw        = $Param{PW} || '';
    my $CryptedPw = '';

    my $ConfigObject = $Kernel::OM->Get('Kernel::Config');

    my $CryptType = $ConfigObject->Get('AuthModule::DB::CryptType') || 'sha2';

    # crypt plain (no crypt at all)
    if ( $CryptType eq 'plain' ) {
        $CryptedPw = $Pw;
    }

    # crypt with UNIX crypt
    elsif ( $CryptType eq 'crypt' ) {

        # encode output, needed by crypt() only non utf8 signs
        $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Pw );
        $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Param{UserLogin} );

        $CryptedPw = crypt( $Pw, $Param{UserLogin} );
    }

    # crypt with md5
    elsif ( $CryptType eq 'md5' || !$CryptType ) {

        # encode output, needed by unix_md5_crypt() only non utf8 signs
        $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Pw );
        $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Param{UserLogin} );

        $CryptedPw = unix_md5_crypt( $Pw, $Param{UserLogin} );
    }

    # crypt with md5 (compatible with Apache's .htpasswd files)
    elsif ( $CryptType eq 'apr1' ) {

        # encode output, needed by unix_md5_crypt() only non utf8 signs
        $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Pw );
        $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Param{UserLogin} );

        $CryptedPw = apache_md5_crypt( $Pw, $Param{UserLogin} );
    }

    # crypt with sha1
    elsif ( $CryptType eq 'sha1' ) {

        my $SHAObject = Digest::SHA->new('sha1');
        $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Pw );
        $SHAObject->add($Pw);
        $CryptedPw = $SHAObject->hexdigest();
    }

    # crypt with sha512
    elsif ( $CryptType eq 'sha512' ) {

        my $SHAObject = Digest::SHA->new('sha512');
        $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Pw );
        $SHAObject->add($Pw);
        $CryptedPw = $SHAObject->hexdigest();
    }

    # bcrypt
    elsif ( $CryptType eq 'bcrypt' ) {

        if ( !$Kernel::OM->Get('Kernel::System::Main')->Require('Crypt::Eksblowfish::Bcrypt') ) {
            $Kernel::OM->Get('Kernel::System::Log')->Log(
                Priority => 'error',
                Message  =>
                    "User: '$User{UserLogin}' tried to store password with bcrypt but 'Crypt::Eksblowfish::Bcrypt' is not installed!",
            );
            return;
        }

        my $Cost = $ConfigObject->Get('AuthModule::DB::bcryptCost') // 12;

        # Don't allow values smaller than 9 for security.
        $Cost = 9 if $Cost < 9;

        # Current Crypt::Eksblowfish::Bcrypt limit is 31.
        $Cost = 31 if $Cost > 31;

        my $Salt = $Kernel::OM->Get('Kernel::System::Main')->GenerateRandomString( Length => 16 );

        # remove UTF8 flag, required by Crypt::Eksblowfish::Bcrypt
        $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Pw );

        # calculate password hash
        my $Octets = Crypt::Eksblowfish::Bcrypt::bcrypt_hash(
            {
                key_nul => 1,
                cost    => $Cost,
                salt    => $Salt,
            },
            $Pw
        );

        # We will store cost and salt in the password string so that it can be decoded
        #   in future even if we use a higher cost by default.
        $CryptedPw = "BCRYPT:$Cost:$Salt:" . Crypt::Eksblowfish::Bcrypt::en_base64($Octets);
    }

    # crypt with sha256 as fallback
    else {

        my $SHAObject = Digest::SHA->new('sha256');

        # encode output, needed by sha256_hex() only non utf8 signs
        $Kernel::OM->Get('Kernel::System::Encode')->EncodeOutput( \$Pw );

        $SHAObject->add($Pw);
        $CryptedPw = $SHAObject->hexdigest();
    }

    # update db
    my $UserLogin = lc $Param{UserLogin};
    return if !$Kernel::OM->Get('Kernel::System::DB')->Do(
        SQL => "UPDATE $Self->{UserTable} SET $Self->{UserTableUserPW} = ? "
            . " WHERE $Self->{Lower}($Self->{UserTableUser}) = ?",
        Bind => [ \$CryptedPw, \$UserLogin ],
    );

    # log notice
    $Kernel::OM->Get('Kernel::System::Log')->Log(
        Priority => 'notice',
        Message  => "User: '$Param{UserLogin}' changed password successfully!",
    );

    my $SystemTime = $Kernel::OM->Get('Kernel::System::Time')->SystemTime();

    # Set password change time
    $Self->SetPreferences(
        Key    => 'UserLastPwChangeTime',
        Value  => $SystemTime,
        UserID => $User{UserID},
    );

    # Reset UserLoginFailed
    $Self->SetPreferences(
        Key    => 'UserLoginFailed',
        Value  => 0,
        UserID => $User{UserID},
    );

    return 1;
}

=head2 UserLookup()

user login or id lookup

    my $UserLogin = $UserObject->UserLookup(
        UserID => 1,
        Silent => 1, # optional, don't generate log entry if user was not found
    );

    my $UserID = $UserObject->UserLookup(
        UserLogin => 'some_user_login',
        Silent    => 1, # optional, don't generate log entry if user was not found
    );

=cut

sub UserLookup {
    my ( $Self, %Param ) = @_;

    # check needed stuff
    if ( !$Param{UserLogin} && !$Param{UserID} ) {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => 'Need UserLogin or UserID!'
        );
        return;
    }

    # get database object
    my $DBObject = $Kernel::OM->Get('Kernel::System::DB');

    if ( $Param{UserLogin} ) {

        # check cache
        my $CacheKey = 'UserLookup::ID::' . $Param{UserLogin};
        my $Cache    = $Kernel::OM->Get('Kernel::System::Cache')->Get(
            Type => $Self->{CacheType},
            Key  => $CacheKey,
        );
        return $Cache if $Cache;

        # build sql query
        my $UserLogin = lc $Param{UserLogin};

        return if !$DBObject->Prepare(
            SQL => "SELECT $Self->{UserTableUserID} FROM $Self->{UserTable} "
                . " WHERE $Self->{Lower}($Self->{UserTableUser}) = ?",
            Bind  => [ \$UserLogin ],
            Limit => 1,
        );

        # fetch the result
        my $ID;
        while ( my @Row = $DBObject->FetchrowArray() ) {
            $ID = $Row[0];
        }

        if ( !$ID ) {
            if ( !$Param{Silent} ) {
                $Kernel::OM->Get('Kernel::System::Log')->Log(
                    Priority => 'error',
                    Message  => "No UserID found for '$Param{UserLogin}'!",
                );
            }
            return;
        }

        # set cache
        $Kernel::OM->Get('Kernel::System::Cache')->Set(
            Type  => $Self->{CacheType},
            TTL   => $Self->{CacheTTL},
            Key   => $CacheKey,
            Value => $ID,
        );

        return $ID;
    }

    else {

        # check cache
        my $CacheKey = 'UserLookup::Login::' . $Param{UserID};
        my $Cache    = $Kernel::OM->Get('Kernel::System::Cache')->Get(
            Type => $Self->{CacheType},
            Key  => $CacheKey,
        );
        return $Cache if $Cache;

        # build sql query
        return if !$DBObject->Prepare(
            SQL => "SELECT $Self->{UserTableUser} FROM $Self->{UserTable} "
                . " WHERE $Self->{UserTableUserID} = ?",
            Bind  => [ \$Param{UserID} ],
            Limit => 1,
        );

        # fetch the result
        my $Login;
        while ( my @Row = $DBObject->FetchrowArray() ) {
            $Login = $Row[0];
        }

        if ( !$Login ) {
            if ( !$Param{Silent} ) {
                $Kernel::OM->Get('Kernel::System::Log')->Log(
                    Priority => 'error',
                    Message  => "No UserLogin found for '$Param{UserID}'!",
                );
            }
            return;
        }

        # set cache
        $Kernel::OM->Get('Kernel::System::Cache')->Set(
            Type  => $Self->{CacheType},
            TTL   => $Self->{CacheTTL},
            Key   => $CacheKey,
            Value => $Login,
        );

        return $Login;
    }
}

=head2 UserName()

get user name

    my $Name = $UserObject->UserName(
        User => 'some-login',
    );

    or

    my $Name = $UserObject->UserName(
        UserID => 123,
    );

=cut

sub UserName {
    my ( $Self, %Param ) = @_;

    my %User = $Self->GetUserData(%Param);

    return if !%User;
    return $User{UserFullname};
}

=head2 UserList()

return a hash with all users

    my %List = $UserObject->UserList(
        Type          => 'Short', # Short|Long, default Short
        Valid         => 1,       # default 1
        NoOutOfOffice => 1,       # (optional) default 0
    );

=cut

sub UserList {
    my ( $Self, %Param ) = @_;

    my $Type = $Param{Type} || 'Short';

    # set valid option
    my $Valid = $Param{Valid} // 1;

    # get config object
    my $ConfigObject = $Kernel::OM->Get('Kernel::Config');

    # get configuration for the full name order
    my $FirstnameLastNameOrder = $ConfigObject->Get('FirstnameLastnameOrder') || 0;
    my $NoOutOfOffice          = $Param{NoOutOfOffice}                        || 0;

    # check cache
    my $CacheKey = join '::', 'UserList', $Type, $Valid, $FirstnameLastNameOrder, $NoOutOfOffice;
    my $Cache    = $Kernel::OM->Get('Kernel::System::Cache')->Get(
        Type => $Self->{CacheType},
        Key  => $CacheKey,
    );
    return %{$Cache} if $Cache;

    my $SelectStr;
    if ( $Type eq 'Short' ) {
        $SelectStr = "$ConfigObject->{DatabaseUserTableUserID}, "
            . " $ConfigObject->{DatabaseUserTableUser}";
    }
    else {
        $SelectStr = "$ConfigObject->{DatabaseUserTableUserID}, "
            . " last_name, first_name, "
            . " $ConfigObject->{DatabaseUserTableUser}";
    }

    my $SQL = "SELECT $SelectStr FROM $ConfigObject->{DatabaseUserTable}";

    # sql query
    if ($Valid) {
        $SQL
            .= " WHERE valid_id IN ( ${\(join ', ', $Kernel::OM->Get('Kernel::System::Valid')->ValidIDsGet())} )";
    }

    # get database object
    my $DBObject = $Kernel::OM->Get('Kernel::System::DB');

    return if !$DBObject->Prepare( SQL => $SQL );

    # fetch the result
    my %UsersRaw;
    my %Users;
    while ( my @Row = $DBObject->FetchrowArray() ) {
        $UsersRaw{ $Row[0] } = \@Row;
    }

    if ( $Type eq 'Short' ) {
        for my $CurrentUserID ( sort keys %UsersRaw ) {
            $Users{$CurrentUserID} = $UsersRaw{$CurrentUserID}->[1];
        }
    }
    else {
        for my $CurrentUserID ( sort keys %UsersRaw ) {
            my @Data         = @{ $UsersRaw{$CurrentUserID} };
            my $UserFullname = $Self->_UserFullname(
                UserFirstname => $Data[2],
                UserLastname  => $Data[1],
                UserLogin     => $Data[3],
                NameOrder     => $FirstnameLastNameOrder,
            );

            $Users{$CurrentUserID} = $UserFullname;
        }
    }

    # check vacation option
    if ( !$NoOutOfOffice ) {

        USERID:
        for my $UserID ( sort keys %Users ) {
            next USERID if !$UserID;

            my %User = $Self->GetUserData(
                UserID => $UserID,
            );

            if ( $User{LoggedStatusMessage} ) {
                $Users{$UserID} .= ' ' . $User{LoggedStatusMessage};
            }

            if ( $User{OutOfOfficeMessage} ) {
                $Users{$UserID} .= ' ' . $User{OutOfOfficeMessage};
            }
        }
    }

    # set cache
    $Kernel::OM->Get('Kernel::System::Cache')->Set(
        Type  => $Self->{CacheType},
        TTL   => $Self->{CacheTTL},
        Key   => $CacheKey,
        Value => \%Users,
    );

    return %Users;
}

=head2 GenerateRandomPassword()

generate a random password

    my $Password = $UserObject->GenerateRandomPassword();

    or

    my $Password = $UserObject->GenerateRandomPassword(
        Size => 16,
    );

=cut

sub GenerateRandomPassword {
    my ( $Self, %Param ) = @_;

    # generated passwords are eight characters long by default.
    my $Size = $Param{Size} || 8;

    my $Password = $Kernel::OM->Get('Kernel::System::Main')->GenerateRandomString(
        Length => $Size,
    );

    return $Password;
}

=head2 SetPreferences()

set user preferences

    $UserObject->SetPreferences(
        Key    => 'UserComment',
        Value  => 'some comment',
        UserID => 123,
    );

=cut

sub SetPreferences {
    my ( $Self, %Param ) = @_;

    for my $Needed (qw(Key UserID)) {
        if ( !$Param{$Needed} ) {
            $Kernel::OM->Get('Kernel::System::Log')->Log(
                Priority => 'error',
                Message  => "Need $Needed!"
            );
            return;
        }
    }

    # Don't allow overwriting of native user data.
    my %Blacklisted = (
        UserID        => 1,
        UserLogin     => 1,
        UserPw        => 1,
        UserFirstname => 1,
        UserLastname  => 1,
        UserFullname  => 1,
        UserTitle     => 1,
        UserType      => 1,
        ChangeTime    => 1,
        CreateTime    => 1,
        ValidID       => 1,
    );

    return 0 if $Blacklisted{ $Param{Key} };

    $Self->_UserCacheClear( UserID => $Param{UserID} );

    # get current setting
    my %User = $Self->GetUserData(
        UserID        => $Param{UserID},
        NoOutOfOffice => 1,
    );

    # No update needed (treat undef and empty strings as equal).
    my $UserValue  = $User{ $Param{Key} } // '';
    my $ParamValue = $Param{Value}        // '';
    return 1 if $UserValue eq $ParamValue;

    # get user preferences config
    my $GeneratorModule = $Kernel::OM->Get('Kernel::Config')->Get('User::PreferencesModule')
        || 'Kernel::System::User::Preferences::DB';

    # get generator preferences module
    my $PreferencesObject = $Kernel::OM->Get($GeneratorModule);

    # set preferences
    return $PreferencesObject->SetPreferences(%Param);
}

sub _UserCacheClear {
    my ( $Self, %Param ) = @_;

    if ( !$Param{UserID} ) {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => "Need UserID!"
        );
        return;
    }

    my $Login = $Self->UserLookup( UserID => $Param{UserID} );

    my @CacheKeys = (
        "UserLookup::ID::$Login",
        "UserLookup::Login::$Param{UserID}",
        glob <<EOF,
GetUserData::User::${Login}::{0,1}::{0,1,2,3,4,5,6,7,8,9}::{0,1}
GetUserData::UserID::$Param{UserID}::{0,1}::{0,1,2,3,4,5,6,7,8,9}::{0,1}
UserList::Short::{0,1}::{0,1,2,3,4,5,6,7,8,9}::{0,1}
UserList::Long::{0,1}::{0,1,2,3,4,5,6,7,8,9}::{0,1}
EOF
    );
    my $CacheObject = $Kernel::OM->Get('Kernel::System::Cache');

    for my $CacheKey (@CacheKeys) {
        $CacheObject->Delete(
            Type => $Self->{CacheType},
            Key  => $CacheKey,
        );
    }

    return 1;
}

=head2 GetPreferences()

get user preferences

    my %Preferences = $UserObject->GetPreferences(
        UserID => 123,
    );

=cut

sub GetPreferences {
    my ( $Self, %Param ) = @_;

    # get user preferences config
    my $GeneratorModule = $Kernel::OM->Get('Kernel::Config')->Get('User::PreferencesModule')
        || 'Kernel::System::User::Preferences::DB';

    # get generator preferences module
    my $PreferencesObject = $Kernel::OM->Get($GeneratorModule);

    return $PreferencesObject->GetPreferences(%Param);
}

=head2 SearchPreferences()

search in user preferences

    my %UserList = $UserObject->SearchPreferences(
        Key   => 'UserEmail',
        Value => 'email@example.com',   # optional, limit to a certain value/pattern
    );

=cut

sub SearchPreferences {
    my ( $Self, %Param ) = @_;

    # get user preferences config
    my $GeneratorModule = $Kernel::OM->Get('Kernel::Config')->Get('User::PreferencesModule')
        || 'Kernel::System::User::Preferences::DB';

    # get generator preferences module
    my $PreferencesObject = $Kernel::OM->Get($GeneratorModule);

    return $PreferencesObject->SearchPreferences(%Param);
}

=head2 TokenGenerate()

generate a random token

    my $Token = $UserObject->TokenGenerate(
        UserID => 123,
    );

=cut

sub TokenGenerate {
    my ( $Self, %Param ) = @_;

    # check needed stuff
    if ( !$Param{UserID} ) {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => "Need UserID!"
        );
        return;
    }
    my $Token = $Kernel::OM->Get('Kernel::System::Main')->GenerateRandomString(
        Length => 15,
    );

    # save token in preferences
    $Self->SetPreferences(
        Key    => 'UserToken',
        Value  => $Token,
        UserID => $Param{UserID},
    );

    return $Token;
}

=head2 TokenCheck()

check password token

    my $Valid = $UserObject->TokenCheck(
        Token  => $Token,
        UserID => 123,
    );

=cut

sub TokenCheck {
    my ( $Self, %Param ) = @_;

    # check needed stuff
    if ( !$Param{Token} || !$Param{UserID} ) {
        $Kernel::OM->Get('Kernel::System::Log')->Log(
            Priority => 'error',
            Message  => 'Need Token and UserID!'
        );
        return;
    }

    # get preferences token
    my %Preferences = $Self->GetPreferences(
        UserID => $Param{UserID},
    );

    # check requested vs. stored token
    if ( $Preferences{UserToken} && $Preferences{UserToken} eq $Param{Token} ) {

        # reset password token
        $Self->SetPreferences(
            Key    => 'UserToken',
            Value  => '',
            UserID => $Param{UserID},
        );

        # return true if token is valid
        return 1;
    }

    # return false if token is invalid
    return;
}

=begin Internal:

Private functions used by this package (not part of the documented public API).

=end Internal:

=head2 _UserFullname()

Builds the user fullname based on firstname, lastname and login. The order
can be configured.

    my $Fullname = $Object->_UserFullname(
        UserFirstname => 'Test',
        UserLastname  => 'Person',
        UserLogin     => 'tp',
        NameOrder     => 0,         # optional 0, 1, 2, 3, 4, 5
    );

=cut

sub _UserFullname {
    my ( $Self, %Param ) = @_;

    for my $Needed (qw(UserFirstname UserLastname UserLogin)) {
        if ( !$Param{$Needed} ) {
            $Kernel::OM->Get('Kernel::System::Log')->Log(
                Priority => 'error',
                Message  => "Need $Needed!",
            );

            return;
        }
    }

    my $FirstnameLastNameOrder = $Param{NameOrder} || 0;

    my $UserFullname;
    if ( $FirstnameLastNameOrder eq '0' ) {
        $UserFullname = $Param{UserFirstname} . ' '
            . $Param{UserLastname};
    }
    elsif ( $FirstnameLastNameOrder eq '1' ) {
        $UserFullname = $Param{UserLastname} . ', '
            . $Param{UserFirstname};
    }
    elsif ( $FirstnameLastNameOrder eq '2' ) {
        $UserFullname = $Param{UserFirstname} . ' '
            . $Param{UserLastname} . ' ('
            . $Param{UserLogin} . ')';
    }
    elsif ( $FirstnameLastNameOrder eq '3' ) {
        $UserFullname = $Param{UserLastname} . ', '
            . $Param{UserFirstname} . ' ('
            . $Param{UserLogin} . ')';
    }
    elsif ( $FirstnameLastNameOrder eq '4' ) {
        $UserFullname = '(' . $Param{UserLogin}
            . ') ' . $Param{UserFirstname}
            . ' ' . $Param{UserLastname};
    }
    elsif ( $FirstnameLastNameOrder eq '5' ) {
        $UserFullname = '(' . $Param{UserLogin}
            . ') ' . $Param{UserLastname}
            . ', ' . $Param{UserFirstname};
    }
    elsif ( $FirstnameLastNameOrder eq '6' ) {
        $UserFullname = $Param{UserLastname} . ' '
            . $Param{UserFirstname};
    }
    elsif ( $FirstnameLastNameOrder eq '7' ) {
        $UserFullname = $Param{UserLastname} . ' '
            . $Param{UserFirstname} . ' ('
            . $Param{UserLogin} . ')';
    }
    elsif ( $FirstnameLastNameOrder eq '8' ) {
        $UserFullname = '(' . $Param{UserLogin}
            . ') ' . $Param{UserLastname}
            . ' ' . $Param{UserFirstname};
    }
    elsif ( $FirstnameLastNameOrder eq '9' ) {
        $UserFullname = $Param{UserLastname} . $Param{UserFirstname};
    }
    return $UserFullname;
}

=head2 UserLoginExistsCheck()

return 1 if another user with this login (username) already exists

    $Exist = $UserObject->UserLoginExistsCheck(
        UserLogin => 'Some::UserLogin',
        UserID => 1, # optional
    );

=cut

sub UserLoginExistsCheck {
    my ( $Self, %Param ) = @_;

    # get database object
    my $DBObject = $Kernel::OM->Get('Kernel::System::DB');

    return if !$DBObject->Prepare(
        SQL =>
            "SELECT $Self->{UserTableUserID} FROM $Self->{UserTable} WHERE $Self->{UserTableUser} = ?",
        Bind => [ \$Param{UserLogin} ],
    );

    # fetch the result
    my $Flag;
    while ( my @Row = $DBObject->FetchrowArray() ) {
        if ( !$Param{UserID} || $Param{UserID} ne $Row[0] ) {
            $Flag = 1;
        }
    }
    if ($Flag) {
        return 1;
    }
    return 0;
}

1;

=head1 TERMS AND CONDITIONS

This software is part of the OTRS project (L<https://otrs.org/>).

This software comes with ABSOLUTELY NO WARRANTY. For details, see
the enclosed file COPYING for license information (GPL). If you
did not receive this file, see L<https://www.gnu.org/licenses/gpl-3.0.txt>.

=cut
