# --
# Copyright (C) 2001-2020 OTRS AG, https://otrs.com/
# --
# 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::Modules::AdminAppointmentNotificationEvent;

use strict;
use warnings;

our $ObjectManagerDisabled = 1;

use Kernel::System::VariableCheck qw(:all);
use Kernel::Language qw(Translatable);

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

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

    return $Self;
}

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

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

    if ( $RichText && !$ConfigObject->Get("Frontend::Admin::$Self->{Action}")->{RichText} ) {
        $RichText = 0;
    }

    # set type for notifications
    my $ContentType = 'text/plain';
    if ($RichText) {
        $ContentType = 'text/html';
    }

    my $ParamObject             = $Kernel::OM->Get('Kernel::System::Web::Request');
    my $LayoutObject            = $Kernel::OM->Get('Kernel::Output::HTML::Layout');
    my $NotificationEventObject = $Kernel::OM->Get('Kernel::System::NotificationEvent');
    my $MainObject              = $Kernel::OM->Get('Kernel::System::Main');
    my $Notification            = $ParamObject->GetParam( Param => 'Notification' );

    # get registered transport layers
    my %RegisteredTransports = %{ $Kernel::OM->Get('Kernel::Config')->Get('AppointmentNotification::Transport') || {} };

    # ------------------------------------------------------------ #
    # change
    # ------------------------------------------------------------ #
    if ( $Self->{Subaction} eq 'Change' ) {

        # get notification id
        my $ID = $ParamObject->GetParam( Param => 'ID' ) || '';

        # get notification data
        my %Data = $NotificationEventObject->NotificationGet(
            ID => $ID,
        );

        my $Output = $LayoutObject->Header();
        $Output .= $LayoutObject->NavigationBar();
        $Self->_Edit(
            %Data,
            Action   => 'Change',
            RichText => $RichText,
        );
        $Output .= $LayoutObject->Output(
            TemplateFile => 'AdminAppointmentNotificationEvent',
            Data         => \%Param,
        );
        $Output .= $LayoutObject->Footer();

        return $Output;
    }

    # ------------------------------------------------------------ #
    # change action
    # ------------------------------------------------------------ #
    elsif ( $Self->{Subaction} eq 'ChangeAction' ) {

        # challenge token check for write action
        $LayoutObject->ChallengeTokenCheck();

        my %GetParam;
        for my $Parameter (
            qw(ID Name Comment ValidID Events IsVisibleForCustomer Transports)
            )
        {
            $GetParam{$Parameter} = $ParamObject->GetParam( Param => $Parameter ) || '';
        }
        PARAMETER:
        for my $Parameter (
            qw(Recipients RecipientAgents RecipientGroups RecipientRoles
            Events CalendarID TeamID ResourceID Title Location
            IsVisibleForCustomer Transports OncePerDay SendOnOutOfOffice
            VisibleForAgent VisibleForAgentTooltip LanguageID AgentEnabledByDefault)
            )
        {
            my @Data = $ParamObject->GetArray( Param => $Parameter );
            next PARAMETER if !@Data;
            $GetParam{Data}->{$Parameter} = \@Data;
        }

        # get the subject and body for all languages
        for my $LanguageID ( @{ $GetParam{Data}->{LanguageID} } ) {

            my $Subject = $ParamObject->GetParam( Param => $LanguageID . '_Subject' ) || '';
            my $Body    = $ParamObject->GetParam( Param => $LanguageID . '_Body' )    || '';

            $GetParam{Message}->{$LanguageID} = {
                Subject     => $Subject,
                Body        => $Body,
                ContentType => $ContentType,
            };

            # set server error flag if field is empty
            if ( !$Subject ) {
                $GetParam{ $LanguageID . '_SubjectServerError' } = "ServerError";
            }
            if ( !$Body ) {
                $GetParam{ $LanguageID . '_BodyServerError' } = "ServerError";
            }
        }

        # get transport settings values
        if ( IsHashRefWithData( \%RegisteredTransports ) ) {

            TRANSPORT:
            for my $Transport ( sort keys %RegisteredTransports ) {

                next TRANSPORT if !IsHashRefWithData( $RegisteredTransports{$Transport} );
                next TRANSPORT if !$RegisteredTransports{$Transport}->{Module};

                if ( !$MainObject->Require( $RegisteredTransports{$Transport}->{Module}, Silent => 1 ) ) {
                    next TRANSPORT;
                }

                # get transport settings string from transport object
                $Kernel::OM->Get( $RegisteredTransports{$Transport}->{Module} )->TransportParamSettingsGet(
                    GetParam => \%GetParam,
                );
            }
        }

        # update
        my $Ok;
        my $DuplicatedEntry = 0;
        my $Error           = 0;

        # Check for 'Additional recipient' field value length.
        if ( $GetParam{Data}->{RecipientEmail} && length $GetParam{Data}->{RecipientEmail} > 200 ) {
            $GetParam{RecipientEmailServerError} = "ServerError";
            $Error = 1;
        }

        $GetParam{Data}->{NotificationType} = ['Appointment'];

        # Get a list of all available notifications and check if a notification with the
        # same name and another type already exists in the database.
        my %NotificationList = $NotificationEventObject->NotificationList(
            Type    => 'Appointment',
            Details => 1,
            All     => 1,
        );

        NOTIFICATIONID:
        for my $NotificationID ( sort keys %NotificationList ) {

            next NOTIFICATIONID if !$NotificationID;
            next NOTIFICATIONID if $GetParam{Name} ne $NotificationList{$NotificationID}->{Name};

            if (
                $GetParam{Name} eq $NotificationList{$NotificationID}->{Name}
                && $GetParam{ID} ne $NotificationID
                )
            {
                $DuplicatedEntry = 1;
            }
        }

        if ( !$DuplicatedEntry && !$Error ) {
            $Ok = $NotificationEventObject->NotificationUpdate(
                %GetParam,
                UserID => $Self->{UserID},
            );
        }

        if ($Ok) {

            # if the user would like to continue editing the notification event, just redirect to the edit screen
            if (
                defined $ParamObject->GetParam( Param => 'ContinueAfterSave' )
                && ( $ParamObject->GetParam( Param => 'ContinueAfterSave' ) eq '1' )
                )
            {
                my $ID = $ParamObject->GetParam( Param => 'ID' ) || '';
                return $LayoutObject->Redirect(
                    OP => "Action=$Self->{Action};Subaction=Change;ID=$ID;Notification=Update",
                );
            }
            else {

                # otherwise return to overview
                return $LayoutObject->Redirect( OP => "Action=$Self->{Action};Notification=Update" );
            }
        }
        else {
            for my $Needed (qw(Name Events Transports)) {
                $GetParam{ $Needed . "ServerError" } = "";
                if ( $GetParam{$Needed} eq '' ) {
                    $GetParam{ $Needed . "ServerError" } = "ServerError";
                }
            }

            my $Output = $LayoutObject->Header();
            $Output .= $LayoutObject->NavigationBar();

            if ($DuplicatedEntry) {
                $Output .= $LayoutObject->Notify(
                    Priority => 'Error',
                    Info     => Translatable('Notification name already exists!')
                );
            }

            $Output .= $LayoutObject->Notify( Priority => 'Error' );
            $Self->_Edit(
                %GetParam,
                Action   => 'Change',
                RichText => $RichText,
            );
            $Output .= $LayoutObject->Output(
                TemplateFile => 'AdminAppointmentNotificationEvent',
                Data         => \%Param,
            );
            $Output .= $LayoutObject->Footer();

            return $Output;
        }
    }

    # ------------------------------------------------------------ #
    # add
    # ------------------------------------------------------------ #
    elsif ( $Self->{Subaction} eq 'Add' ) {

        my $Output = $LayoutObject->Header();
        $Output .= $LayoutObject->NavigationBar();
        $Self->_Edit(
            Action   => 'Add',
            RichText => $RichText,
        );
        $Output .= $LayoutObject->Output(
            TemplateFile => 'AdminAppointmentNotificationEvent',
            Data         => \%Param,
        );
        $Output .= $LayoutObject->Footer();

        return $Output;
    }

    # ------------------------------------------------------------ #
    # add action
    # ------------------------------------------------------------ #
    elsif ( $Self->{Subaction} eq 'AddAction' ) {

        # challenge token check for write action
        $LayoutObject->ChallengeTokenCheck();

        my %GetParam;
        for my $Parameter (
            qw(Name Comment ValidID Events IsVisibleForCustomer Transports)
            )
        {
            $GetParam{$Parameter} = $ParamObject->GetParam( Param => $Parameter ) || '';
        }
        PARAMETER:
        for my $Parameter (
            qw(Recipients RecipientAgents RecipientRoles RecipientGroups Events
            IsVisibleForCustomer Transports OncePerDay SendOnOutOfOffice
            VisibleForAgent VisibleForAgentTooltip LanguageID AgentEnabledByDefault)
            )
        {
            my @Data = $ParamObject->GetArray( Param => $Parameter );
            next PARAMETER if !@Data;
            $GetParam{Data}->{$Parameter} = \@Data;
        }

        # get the subject and body for all languages
        for my $LanguageID ( @{ $GetParam{Data}->{LanguageID} } ) {

            my $Subject = $ParamObject->GetParam( Param => $LanguageID . '_Subject' ) || '';
            my $Body    = $ParamObject->GetParam( Param => $LanguageID . '_Body' )    || '';

            $GetParam{Message}->{$LanguageID} = {
                Subject     => $Subject,
                Body        => $Body,
                ContentType => $ContentType,
            };

            # set server error flag if field is empty
            if ( !$Subject ) {
                $GetParam{ $LanguageID . '_SubjectServerError' } = "ServerError";
            }
            if ( !$Body ) {
                $GetParam{ $LanguageID . '_BodyServerError' } = "ServerError";
            }
        }

        # get transport settings values
        if ( IsHashRefWithData( \%RegisteredTransports ) ) {

            TRANSPORT:
            for my $Transport ( sort keys %RegisteredTransports ) {

                next TRANSPORT if !IsHashRefWithData( $RegisteredTransports{$Transport} );
                next TRANSPORT if !$RegisteredTransports{$Transport}->{Module};

                if ( !$MainObject->Require( $RegisteredTransports{$Transport}->{Module}, Silent => 1 ) ) {
                    next TRANSPORT;
                }

                # get transport settings string from transport object
                $Kernel::OM->Get( $RegisteredTransports{$Transport}->{Module} )->TransportParamSettingsGet(
                    GetParam => \%GetParam,
                );
            }
        }

        # add
        my $ID;
        my $DuplicatedEntry = 0;
        my $Error           = 0;

        # Check for 'Additional recipient' field value length.
        if ( $GetParam{Data}->{RecipientEmail} && length $GetParam{Data}->{RecipientEmail} > 200 ) {
            $GetParam{RecipientEmailServerError} = "ServerError";
            $Error = 1;
        }

        $GetParam{Data}->{NotificationType} = ['Appointment'];

        # Get a list of all available notifications and check if a notification with the
        # same name and another type already exists in the database.
        my %NotificationList = $NotificationEventObject->NotificationList(
            Type    => 'Appointment',
            Details => 1,
            All     => 1,
        );

        NOTIFICATIONID:
        for my $NotificationID ( sort keys %NotificationList ) {

            next NOTIFICATIONID if !$NotificationID;
            next NOTIFICATIONID if $GetParam{Name} ne $NotificationList{$NotificationID}->{Name};

            $DuplicatedEntry = 1;
        }

        if ( !$DuplicatedEntry && !$Error ) {
            $ID = $NotificationEventObject->NotificationAdd(
                %GetParam,
                UserID => $Self->{UserID},
            );
        }

        if ( !$GetParam{Data}->{Transports} ) {
            $GetParam{TransportServerError} = "ServerError";
        }

        if ($ID) {
            $Self->_Overview();
            my $Output = $LayoutObject->Header();
            $Output .= $LayoutObject->NavigationBar();
            $Output .= $LayoutObject->Notify( Info => Translatable('Notification added!') );
            $Output .= $LayoutObject->Output(
                TemplateFile => 'AdminAppointmentNotificationEvent',
                Data         => \%Param,
            );
            $Output .= $LayoutObject->Footer();

            return $Output;
        }
        else {
            for my $Needed (qw(Name Events Transports)) {
                $GetParam{ $Needed . "ServerError" } = "";
                if ( $GetParam{$Needed} eq '' ) {
                    $GetParam{ $Needed . "ServerError" } = "ServerError";
                }
            }

            my $Output = $LayoutObject->Header();
            $Output .= $LayoutObject->NavigationBar();

            if ($DuplicatedEntry) {
                $Output .= $LayoutObject->Notify(
                    Priority => 'Error',
                    Info     => Translatable('Notification name already exists!')
                );
            }

            $Output .= $LayoutObject->Notify( Priority => 'Error' );
            $Self->_Edit(
                %GetParam,
                Action   => 'Add',
                RichText => $RichText,
            );
            $Output .= $LayoutObject->Output(
                TemplateFile => 'AdminAppointmentNotificationEvent',
                Data         => \%Param,
            );
            $Output .= $LayoutObject->Footer();

            return $Output;
        }
    }

    # ------------------------------------------------------------ #
    # delete
    # ------------------------------------------------------------ #
    if ( $Self->{Subaction} eq 'Delete' ) {

        # challenge token check for write action
        $LayoutObject->ChallengeTokenCheck();

        my %GetParam;
        for my $Parameter (qw(ID)) {
            $GetParam{$Parameter} = $ParamObject->GetParam( Param => $Parameter ) || '';
        }

        my $Delete = $NotificationEventObject->NotificationDelete(
            ID     => $GetParam{ID},
            UserID => $Self->{UserID},
        );
        if ( !$Delete ) {
            return $LayoutObject->ErrorScreen();
        }

        return $LayoutObject->Redirect( OP => "Action=$Self->{Action}" );
    }

    # ------------------------------------------------------------ #
    # NotificationExport
    # ------------------------------------------------------------ #
    elsif ( $Self->{Subaction} eq 'NotificationExport' ) {

        my $NotificationID = $ParamObject->GetParam( Param => 'ID' ) || '';
        my $NotificationData;
        my %NotificationSingleData;
        my $Filename = 'Export_Notification.yml';

        if ($NotificationID) {

            %NotificationSingleData = $NotificationEventObject->NotificationGet(
                ID     => $NotificationID,
                UserID => $Self->{UserID},
            );

            if ( !IsHashRefWithData( \%NotificationSingleData ) ) {
                return $LayoutObject->ErrorScreen(
                    Message => $LayoutObject->{LanguageObject}
                        ->Translate( 'There was an error getting data for Notification with ID:%s!', $NotificationID ),
                );
            }

            my $NotificationName = $NotificationSingleData{Name};
            $NotificationName =~ s{[^a-zA-Z0-9-_]}{_}xmsg;    # cleanup name for saving

            $Filename         = 'Export_Notification_' . $NotificationName . '.yml';
            $NotificationData = [ \%NotificationSingleData ];
        }
        else {

            my %Notificationdetails = $NotificationEventObject->NotificationList(
                Type    => 'Appointment',
                UserID  => $Self->{UserID},
                Details => 1,
            );

            my @Data;
            for my $ItemID ( sort keys %Notificationdetails ) {
                push @Data, $Notificationdetails{$ItemID};
            }
            $NotificationData = \@Data;
        }

        # convert the Notification data hash to string
        my $NotificationDataYAML = $Kernel::OM->Get('Kernel::System::YAML')->Dump( Data => $NotificationData );

        # send the result to the browser
        return $LayoutObject->Attachment(
            ContentType => 'text/html; charset=' . $LayoutObject->{Charset},
            Content     => $NotificationDataYAML,
            Type        => 'attachment',
            Filename    => $Filename,
            NoCache     => 1,
        );
    }

    # ------------------------------------------------------------ #
    # NotificationCopy
    # ------------------------------------------------------------ #
    elsif ( $Self->{Subaction} eq 'NotificationCopy' ) {

        my $NotificationID = $ParamObject->GetParam( Param => 'ID' ) || '';

        # challenge token check for write action
        $LayoutObject->ChallengeTokenCheck();

        # get Notification data
        my %NotificationData = $NotificationEventObject->NotificationGet(
            ID     => $NotificationID,
            UserID => $Self->{UserID},
        );
        if ( !IsHashRefWithData( \%NotificationData ) ) {
            return $LayoutObject->ErrorScreen(
                Message => $LayoutObject->{LanguageObject}->Translate( 'Unknown Notification %s!', $NotificationID ),
            );
        }

        # create new Notification name
        my $NotificationName = $LayoutObject->{LanguageObject}->Translate( '%s (copy)', $NotificationData{Name} );

        # otherwise save configuration and return to overview screen
        my $NewNotificationID = $NotificationEventObject->NotificationAdd(
            %NotificationData,
            Name   => $NotificationName,
            UserID => $Self->{UserID},
        );

        # show error if can't create
        if ( !$NewNotificationID ) {
            return $LayoutObject->ErrorScreen(
                Message => Translatable("There was an error creating the Notification"),
            );
        }

        # return to overview
        return $LayoutObject->Redirect( OP => "Action=$Self->{Action}" );
    }

    # ------------------------------------------------------------ #
    # NotificationImport
    # ------------------------------------------------------------ #
    if ( $Self->{Subaction} eq 'NotificationImport' ) {

        # challenge token check for write action
        $LayoutObject->ChallengeTokenCheck();

        my $FormID      = $ParamObject->GetParam( Param => 'FormID' ) || '';
        my %UploadStuff = $ParamObject->GetUploadAll(
            Param  => 'FileUpload',
            Source => 'string',
        );

        my $OverwriteExistingNotifications = $ParamObject->GetParam( Param => 'OverwriteExistingNotifications' ) || '';

        my $NotificationImport = $NotificationEventObject->NotificationImport(
            Content                        => $UploadStuff{Content},
            Type                           => 'Appointment',
            OverwriteExistingNotifications => $OverwriteExistingNotifications,
            UserID                         => $Self->{UserID},
        );

        if ( !$NotificationImport->{Success} ) {
            my $Message = $NotificationImport->{Message}
                || Translatable(
                'Notifications could not be Imported due to a unknown error, please check OTRS logs for more information'
                );
            return $LayoutObject->ErrorScreen(
                Message => $Message,
            );
        }

        if ( $NotificationImport->{AddedNotifications} ) {
            push @{ $Param{NotifyData} }, {
                Info => $LayoutObject->{LanguageObject}->Translate(
                    'The following Notifications have been added successfully: %s',
                    $NotificationImport->{AddedNotifications}
                ),
            };
        }
        if ( $NotificationImport->{UpdatedNotifications} ) {
            push @{ $Param{NotifyData} }, {
                Info => $LayoutObject->{LanguageObject}->Translate(
                    'The following Notifications have been updated successfully: %s',
                    $NotificationImport->{UpdatedNotifications}
                ),
            };
        }
        if ( $NotificationImport->{NotificationErrors} ) {
            push @{ $Param{NotifyData} }, {
                Priority => 'Error',
                Info     => $LayoutObject->{LanguageObject}->Translate(
                    'There where errors adding/updating the following Notifications: %s. Please check the log file for more information.',
                    $NotificationImport->{NotificationErrors}
                ),
            };
        }

        $Self->_Overview();
        my $Output = $LayoutObject->Header();
        $Output .= $LayoutObject->NavigationBar();

        # show notifications if any
        if ( $Param{NotifyData} ) {
            for my $Notification ( @{ $Param{NotifyData} } ) {
                $Output .= $LayoutObject->Notify(
                    %{$Notification},
                );
            }
        }

        $Output .= $LayoutObject->Output(
            TemplateFile => 'AdminAppointmentNotificationEvent',
            Data         => \%Param,
        );
        $Output .= $LayoutObject->Footer();

        return $Output;
    }

    # ------------------------------------------------------------
    # overview
    # ------------------------------------------------------------
    else {
        $Self->_Overview();
        my $Output = $LayoutObject->Header();
        $Output .= $LayoutObject->NavigationBar();
        $Output .= $LayoutObject->Notify( Info => Translatable('Notification updated!') )
            if ( $Notification && $Notification eq 'Update' );
        $Output .= $LayoutObject->Output(
            TemplateFile => 'AdminAppointmentNotificationEvent',
            Data         => \%Param,
        );
        $Output .= $LayoutObject->Footer();

        return $Output;
    }

    return;
}

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

    my $LayoutObject = $Kernel::OM->Get('Kernel::Output::HTML::Layout');

    $LayoutObject->Block(
        Name => 'Overview',
        Data => \%Param,
    );

    $LayoutObject->Block( Name => 'ActionList' );
    $LayoutObject->Block( Name => 'ActionOverview' );

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

    # get list type
    my $TreeView = 0;
    if ( $ConfigObject->Get('Ticket::Frontend::ListType') eq 'tree' ) {
        $TreeView = 1;
    }

    $Param{RecipientsStrg} = $LayoutObject->BuildSelection(
        Data => {
            AppointmentAgents => Translatable('Agent (resources), who are selected within the appointment'),
            AppointmentAgentReadPermissions =>
                Translatable('All agents with (at least) read permission for the appointment (calendar)'),
            AppointmentAgentWritePermissions =>
                Translatable('All agents with write permission for the appointment (calendar)'),
        },
        Name       => 'Recipients',
        Multiple   => 1,
        Size       => 8,
        SelectedID => $Param{Data}->{Recipients},
        Class      => 'Modernize W75pc',
    );

    my %AllAgents = $Kernel::OM->Get('Kernel::System::User')->UserList(
        Type  => 'Long',
        Valid => 1,
    );
    $Param{RecipientAgentsStrg} = $LayoutObject->BuildSelection(
        Data       => \%AllAgents,
        Name       => 'RecipientAgents',
        Multiple   => 1,
        Size       => 4,
        SelectedID => $Param{Data}->{RecipientAgents},
        Class      => 'Modernize W75pc',
    );

    my $GroupObject = $Kernel::OM->Get('Kernel::System::Group');

    $Param{RecipientGroupsStrg} = $LayoutObject->BuildSelection(
        Data       => { $GroupObject->GroupList( Valid => 1 ) },
        Size       => 6,
        Name       => 'RecipientGroups',
        Multiple   => 1,
        SelectedID => $Param{Data}->{RecipientGroups},
        Class      => 'Modernize W75pc',
    );
    $Param{RecipientRolesStrg} = $LayoutObject->BuildSelection(
        Data       => { $GroupObject->RoleList( Valid => 1 ) },
        Size       => 6,
        Name       => 'RecipientRoles',
        Multiple   => 1,
        SelectedID => $Param{Data}->{RecipientRoles},
        Class      => 'Modernize W75pc',
    );

    # Set class name for event string...
    my $EventClass = 'Validate_Required';
    if ( $Param{EventsServerError} ) {
        $EventClass .= ' ' . $Param{EventsServerError};
    }

    my $NotificationConfig = $ConfigObject->Get('Frontend::Admin::AdminAppointmentNotificationEvent');

    # get a list of registered events
    my %RegisteredEvents = $Kernel::OM->Get('Kernel::System::Event')->EventList(
        ObjectTypes => $NotificationConfig->{EventObjectTypes},
    );

    my @Events;
    for my $ObjectType ( sort keys %RegisteredEvents ) {
        push @Events, @{ $RegisteredEvents{$ObjectType} || [] };
    }

    # Suppress these events because of danger of endless loops.
    my %EventBlacklist = (
        ArticleAgentNotification    => 1,
        ArticleCustomerNotification => 1,
    );

    @Events = grep { !$EventBlacklist{$_} } @Events;

    # Build the list...
    $Param{EventsStrg} = $LayoutObject->BuildSelection(
        Data       => \@Events,
        Name       => 'Events',
        Multiple   => 1,
        Size       => 10,
        Class      => $EventClass . ' Modernize W75pc',
        SelectedID => $Param{Data}->{Events},
    );

    my $CalendarObject = $Kernel::OM->Get('Kernel::System::Calendar');

    my @CalendarList = $CalendarObject->CalendarList(
        UserID     => $Self->{UserID},
        Permission => 'ro',
        ValidID    => 0,
    );

    my %CalendarList;

    CALENDAR:
    for my $Calendar (@CalendarList) {

        next CALENDAR if !$Calendar;
        next CALENDAR if !IsHashRefWithData($Calendar);

        $CalendarList{ $Calendar->{CalendarID} } = $Calendar->{CalendarName};
    }

    $Param{CalendarStrg} = $LayoutObject->BuildSelection(
        Data       => \%CalendarList,
        Name       => 'CalendarID',
        Multiple   => 1,
        Size       => 5,
        SelectedID => $Param{Data}->{CalendarID},
        Class      => 'Modernize W75pc',
    );

    $Param{ResourceStrg} = $LayoutObject->BuildSelection(
        Data       => \%AllAgents,
        Name       => 'ResourceID',
        Multiple   => 1,
        Size       => 5,
        SelectedID => $Param{Data}->{ResourceID},
        Class      => 'Modernize W75pc',
    );

    $Param{Title}    = $Param{Data}->{Title}->[0]    || '';
    $Param{Location} = $Param{Data}->{Location}->[0] || '';

    # get valid list
    my %ValidList        = $Kernel::OM->Get('Kernel::System::Valid')->ValidList();
    my %ValidListReverse = reverse %ValidList;

    $Param{ValidOption} = $LayoutObject->BuildSelection(
        Data       => \%ValidList,
        Name       => 'ValidID',
        SelectedID => $Param{ValidID} || $ValidListReverse{valid},
        Class      => 'Modernize W50pc',
    );
    $LayoutObject->Block(
        Name => 'OverviewUpdate',
        Data => \%Param,
    );

    # try to load the team backend
    if ( $Kernel::OM->Get('Kernel::System::Main')->Require( 'Kernel::System::Calendar::Team', Silent => 1 ) ) {

        # instanciate a new team object
        my $TeamObject = Kernel::System::Calendar::Team->new();

        # get a list of available (readable) teams
        my %TeamList = $TeamObject->TeamList(
            Valid  => 0,
            UserID => $Self->{UserID},
        );

        if ( IsHashRefWithData( \%TeamList ) ) {

            # build team selection
            my $TeamStrg = $LayoutObject->BuildSelection(
                Data       => \%TeamList,
                Name       => 'TeamID',
                Multiple   => 1,
                Size       => 5,
                SelectedID => $Param{Data}->{TeamID},
                Class      => 'Modernize W75pc',
            );

            # activate the team section
            $LayoutObject->Block(
                Name => 'OverviewUpdateTeam',
                Data => {
                    TeamStrg => $TeamStrg,
                },
            );
        }
    }

    # add rich text editor
    if ( $Param{RichText} ) {

        # use height/width defined for this screen
        my $Config = $ConfigObject->Get("Frontend::Admin::$Self->{Action}");
        $Param{RichTextHeight} = $Config->{RichTextHeight} || 0;
        $Param{RichTextWidth}  = $Config->{RichTextWidth}  || 0;

        # set up rich text editor
        $LayoutObject->SetRichTextParameters(
            Data => \%Param,
        );
    }

    # get language ids from message parameter, use English if no message is given
    # make sure English is the first language
    my @LanguageIDs;
    if ( IsHashRefWithData( $Param{Message} ) ) {
        if ( $Param{Message}->{en} ) {
            push @LanguageIDs, 'en';
        }
        LANGUAGEID:
        for my $LanguageID ( sort keys %{ $Param{Message} } ) {
            next LANGUAGEID if $LanguageID eq 'en';
            push @LanguageIDs, $LanguageID;
        }
    }
    else {
        @LanguageIDs = ('en');
    }

    # get names of languages in English
    my %DefaultUsedLanguages = %{ $ConfigObject->Get('DefaultUsedLanguages') || {} };

    # get native names of languages
    my %DefaultUsedLanguagesNative = %{ $ConfigObject->Get('DefaultUsedLanguagesNative') || {} };

    my %Languages;
    LANGUAGEID:
    for my $LanguageID ( sort keys %DefaultUsedLanguages ) {

        # next language if there is not set any name for current language
        if ( !$DefaultUsedLanguages{$LanguageID} && !$DefaultUsedLanguagesNative{$LanguageID} ) {
            next LANGUAGEID;
        }

        # get texts in native and default language
        my $Text        = $DefaultUsedLanguagesNative{$LanguageID} || '';
        my $TextEnglish = $DefaultUsedLanguages{$LanguageID}       || '';

        # translate to current user's language
        my $TextTranslated =
            $Kernel::OM->Get('Kernel::Output::HTML::Layout')->{LanguageObject}->Translate($TextEnglish);

        if ( $TextTranslated && $TextTranslated ne $Text ) {
            $Text .= ' - ' . $TextTranslated;
        }

        # next language if there is not set English nor native name of language.
        next LANGUAGEID if !$Text;

        $Languages{$LanguageID} = $Text;
    }

    # copy original list of languages which will be used for rebuilding language selection
    my %OriginalDefaultUsedLanguages = %Languages;

    my $HTMLUtilsObject = $Kernel::OM->Get('Kernel::System::HTMLUtils');

    for my $LanguageID (@LanguageIDs) {

        # format the content according to the content type
        if ( $Param{RichText} ) {

            # make sure body is rich text (if body is based on config)
            if (
                $Param{Message}->{$LanguageID}->{ContentType}
                && $Param{Message}->{$LanguageID}->{ContentType} =~ m{text\/plain}xmsi
                )
            {
                $Param{Message}->{$LanguageID}->{Body} = $HTMLUtilsObject->ToHTML(
                    String => $Param{Message}->{$LanguageID}->{Body},
                );
            }
        }
        else {

            # reformat from HTML to plain
            if (
                $Param{Message}->{$LanguageID}->{ContentType}
                && $Param{Message}->{$LanguageID}->{ContentType} =~ m{text\/html}xmsi
                && $Param{Message}->{$LanguageID}->{Body}
                )
            {
                $Param{Message}->{$LanguageID}->{Body} = $HTMLUtilsObject->ToAscii(
                    String => $Param{Message}->{$LanguageID}->{Body},
                );
            }
        }

        # show the notification for this language
        $LayoutObject->Block(
            Name => 'NotificationLanguage',
            Data => {
                %Param,
                Subject => $Param{Message}->{$LanguageID}->{Subject} || '',
                Body    => $Param{Message}->{$LanguageID}->{Body}    || '',
                LanguageID         => $LanguageID,
                Language           => $Languages{$LanguageID},
                SubjectServerError => $Param{ $LanguageID . '_SubjectServerError' } || '',
                BodyServerError    => $Param{ $LanguageID . '_BodyServerError' } || '',
            },
        );

        # show the button to remove a notification only if it is not the English notification
        if ( $LanguageID ne 'en' ) {
            $LayoutObject->Block(
                Name => 'NotificationLanguageRemoveButton',
                Data => {
                    %Param,
                    LanguageID => $LanguageID,
                },
            );
        }

        # delete language from drop-down list because it is already shown
        delete $Languages{$LanguageID};
    }

    $Param{LanguageStrg} = $LayoutObject->BuildSelection(
        Data         => \%Languages,
        Name         => 'Language',
        Class        => 'Modernize W50pc LanguageAdd',
        Translation  => 1,
        PossibleNone => 1,
        HTMLQuote    => 0,
    );
    $Param{LanguageOrigStrg} = $LayoutObject->BuildSelection(
        Data         => \%OriginalDefaultUsedLanguages,
        Name         => 'LanguageOrig',
        Translation  => 1,
        PossibleNone => 1,
        HTMLQuote    => 0,
    );

    # take over data fields
    KEY:
    for my $Key (
        qw(VisibleForAgent VisibleForAgentTooltip CustomerID CustomerUserID)
        )
    {
        next KEY if !$Param{Data}->{$Key};
        next KEY if !defined $Param{Data}->{$Key}->[0];
        $Param{$Key} = $Param{Data}->{$Key}->[0];
    }

    # set send on out of office checked value
    $Param{SendOnOutOfOfficeChecked} = ( $Param{Data}->{SendOnOutOfOffice} ? 'checked="checked"' : '' );

    # set once per day checked value
    $Param{OncePerDayChecked} = ( $Param{Data}->{OncePerDay} ? 'checked="checked"' : '' );

    my $OTRSBusinessObject      = $Kernel::OM->Get('Kernel::System::OTRSBusiness');
    my $OTRSBusinessIsInstalled = $OTRSBusinessObject->OTRSBusinessIsInstalled();

    # Third option is enabled only when OTRSBusiness is installed in the system.
    $Param{VisibleForAgentStrg} = $LayoutObject->BuildSelection(
        Data => [
            {
                Key   => '0',
                Value => Translatable('No'),
            },
            {
                Key   => '1',
                Value => Translatable('Yes'),
            },
            {
                Key      => '2',
                Value    => Translatable('Yes, but require at least one active notification method.'),
                Disabled => $OTRSBusinessIsInstalled ? 0 : 1,
            }
        ],
        Name       => 'VisibleForAgent',
        Sort       => 'NumericKey',
        Size       => 1,
        SelectedID => $Param{VisibleForAgent},
        Class      => 'Modernize W50pc',
    );

    # include read-only attribute
    if ( !$Param{VisibleForAgent} ) {
        $Param{VisibleForAgentTooltipReadonly} = 'readonly="readonly"';
    }

    # get registered transport layers
    my %RegisteredTransports = %{ $Kernel::OM->Get('Kernel::Config')->Get('AppointmentNotification::Transport') || {} };

    if ( IsHashRefWithData( \%RegisteredTransports ) ) {

        my $MainObject = $Kernel::OM->Get('Kernel::System::Main');

        TRANSPORT:
        for my $Transport (
            sort { $RegisteredTransports{$a}->{Prio} <=> $RegisteredTransports{$b}->{Prio} }
            keys %RegisteredTransports
            )
        {

            next TRANSPORT if !IsHashRefWithData( $RegisteredTransports{$Transport} );
            next TRANSPORT if !$RegisteredTransports{$Transport}->{Module};

            # transport
            $LayoutObject->Block(
                Name => 'TransportRow',
                Data => {
                    Transport     => $Transport,
                    TransportName => $RegisteredTransports{$Transport}->{Name},
                },
            );

            if ( !$MainObject->Require( $RegisteredTransports{$Transport}->{Module}, Silent => 1 ) ) {

                # backend for this transport is not available
                $LayoutObject->Block(
                    Name => 'TransportRowDisabled',
                    Data => {
                        Transport     => $Transport,
                        TransportName => $RegisteredTransports{$Transport}->{Name},
                    },
                );

                # if not standard transport
                if (
                    defined $RegisteredTransports{$Transport}->{IsOTRSBusinessTransport}
                    && $RegisteredTransports{$Transport}->{IsOTRSBusinessTransport} eq '1'
                    && !$OTRSBusinessIsInstalled
                    )
                {

                    # transport
                    $LayoutObject->Block(
                        Name => 'TransportRowRecommendation',
                        Data => {
                            Transport     => $Transport,
                            TransportName => $RegisteredTransports{$Transport}->{Name},
                        },
                    );
                }

                next TRANSPORT;
            }
            else {

                my $TransportObject = $Kernel::OM->Get( $RegisteredTransports{$Transport}->{Module} );

                my $IsActive = 1;

                # Check only if function is available due backwards compatibility.
                if ( $TransportObject->can('IsActive') ) {
                    $IsActive = $TransportObject->IsActive();
                }

                if ($IsActive) {

                    my $TransportChecked = '';
                    if ( grep { $_ eq $Transport } @{ $Param{Data}->{Transports} } ) {
                        $TransportChecked = 'checked="checked"';
                    }

                    # set Email transport selected on add screen
                    if ( $Transport eq 'Email' && !$Param{ID} ) {
                        $TransportChecked = 'checked="checked"';
                    }

                    # get transport settings string from transport object
                    my $TransportSettings =
                        $TransportObject->TransportSettingsDisplayGet(
                        %Param,
                        );

                    # it should decide if the default value for the
                    # notification on AgentPreferences is enabled or not
                    my $AgentEnabledByDefault = 0;
                    if ( grep { $_ eq $Transport } @{ $Param{Data}->{AgentEnabledByDefault} } ) {
                        $AgentEnabledByDefault = 1;
                    }
                    elsif ( !$Param{ID} && defined $RegisteredTransports{$Transport}->{AgentEnabledByDefault} ) {
                        $AgentEnabledByDefault = $RegisteredTransports{$Transport}->{AgentEnabledByDefault};
                    }
                    my $AgentEnabledByDefaultChecked = ( $AgentEnabledByDefault ? 'checked="checked"' : '' );

                    # transport
                    $LayoutObject->Block(
                        Name => 'TransportRowEnabled',
                        Data => {
                            Transport                    => $Transport,
                            TransportName                => $RegisteredTransports{$Transport}->{Name},
                            TransportChecked             => $TransportChecked,
                            SettingsString               => $TransportSettings,
                            AgentEnabledByDefaultChecked => $AgentEnabledByDefaultChecked,
                            TransportsServerError        => $Param{TransportsServerError},
                        },
                    );
                }
                else {

                    # This trasnport needs to be active before use it.
                    $LayoutObject->Block(
                        Name => 'TransportRowNotActive',
                        Data => {
                            Transport     => $Transport,
                            TransportName => $RegisteredTransports{$Transport}->{Name},
                        },
                    );
                }

            }

        }
    }
    else {

        # no transports
        $LayoutObject->Block(
            Name => 'NoDataFoundMsgTransport',
        );
    }

    return 1;
}

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

    my $LayoutObject = $Kernel::OM->Get('Kernel::Output::HTML::Layout');

    $LayoutObject->Block(
        Name => 'Overview',
        Data => \%Param,
    );

    $LayoutObject->Block( Name => 'ActionList' );
    $LayoutObject->Block( Name => 'ActionAdd' );
    $LayoutObject->Block( Name => 'ActionImport' );
    $LayoutObject->Block( Name => 'Filter' );

    $LayoutObject->Block(
        Name => 'OverviewResult',
        Data => \%Param,
    );

    my $NotificationEventObject = $Kernel::OM->Get('Kernel::System::NotificationEvent');

    my %List = $NotificationEventObject->NotificationList( Type => 'Appointment' );

    # if there are any notifications, they are shown
    if (%List) {

        # get valid list
        my %ValidList = $Kernel::OM->Get('Kernel::System::Valid')->ValidList();
        for my $NotificationID ( sort { $List{$a} cmp $List{$b} } keys %List ) {

            my %Data = $NotificationEventObject->NotificationGet(
                ID => $NotificationID,
            );
            $LayoutObject->Block(
                Name => 'OverviewResultRow',
                Data => {
                    Valid => $ValidList{ $Data{ValidID} },
                    %Data,
                },
            );
        }
    }

    # otherwise a no data found message is displayed
    else {
        $LayoutObject->Block(
            Name => 'NoDataFoundMsg',
            Data => {},
        );
    }

    return 1;
}

1;