use strict;
use warnings;

use Qpsmtpd::Constants;
use Qpsmtpd::DSN;

use DBI;

sub register {
    my ($self, $qp) = (shift, shift);

    # some default values
    $self->{database} = $qp->config("fedhq_mysql_database") || "mail";
    $self->{host} = $qp->config("fedhq_mysql_host") || "localhost";
    $self->{port} = $qp->config("fedhq_mysql_port") || "3306";
    $self->{user} = $qp->config("fedhq_mysql_user") || "qpsmtpd";
    $self->{pass} = $qp->config("fedhq_mysql_password");

    $self->createDSN();
    
}


sub createStatements
{
    my $self = shift;

    $self->{rcpt_sth} = $self->{dbh}->prepare("select username,dovecot_server from email_address where alias=? and domain=?");

    $self->{fetch_all_sth} = $self->{dbh}->prepare("select username,dovecot_server from email_address where domain=? and isFetchAll=1");

    $self->{fetch_dovecot_details_sth} = $self->{dbh}->prepare("select username, hostname, port from dovecot_server RIGHT JOIN email_address ON dovecot_server.name = email_address.dovecot_server where alias=? and domain=?");

}

sub connect
{
    my $self = shift;

    $self->{dbh} = DBI->connect($self->{dsn}, $self->{user}, $self->{pass}, { RaiseError => 0}) || 
        $self->log(LOGERROR, "error connecting to DB " . $DBI::errstr);
    
    if ($self->{dbh}->err())
    {
        $self->log(LOGERROR, "error connecting to DB: " . $self->{dbh}->errstr());
        $self->{dbh}=undef;
    }

}

sub disconnect 
{
    my $self = shift;

    $self->{dbh}->disconnect() if ($self->{dbh});
}

sub createDSN 
{
    my $self = shift;
    my $dsn = "DBI:MariaDB:database=" . $self->{database} . ";host=" . $self->{host} . ";port=" . $self->{port};
    $self->{dsn} = $dsn;

    # try to parse the dsn to ensure it is valid
    my @data = DBI->parse_dsn($self->{dsn});

    if (@data == 0)
    {
         $self->log(LOGERROR, "DSN " .  $self->{dsn} . " not valid");
         $self->{dsn}="";
    }

    $self->log(LOGDEBUG, "created DSN " . $self->{dsn});
}

sub updateTransactionWithSmtpInfo
{
    my ($self, $transaction, $recipient) = @_;

    my $queue = $transaction->notes("queue") || {};
    my $rcpt  = $recipient->user . "@" . $recipient->host;
    
    $queue->{$rcpt}->{destination} = "relay";
    $queue->{$rcpt}->{protocol} = "smtp";
    $queue->{$rcpt}->{host} = $self->qp->config("relay_server");
    
    $transaction->notes("queue", $queue);

    return 0;
}

sub updateTransactionWithLmtpInfo 
{
    my ($self, $transaction, $recipient) = @_;

    my $result = $self->{fetch_dovecot_details_sth}->execute($recipient->user, $recipient->host);
    if (!$result) 
    {
        $self->log(LOGERROR, "Failed to fetch dovecot information from the database");        return -1;
    }

    if ($self->{fetch_dovecot_details_sth}->rows == 0)
    {
        $self->log(LOGERROR, "no dovecot information in database found");        
        return -1;
    }
    elsif ($self->{fetch_dovecot_details_sth}->rows > 1)
    {
        $self->log(LOGERROR, "too many dovecot entries in the database");        
        return -1;
    }

    my $row = $self->{fetch_dovecot_details_sth}->fetchrow_hashref;

    my $username = $row->{username};
    my $hostname = $row->{hostname};
    my $port = $row->{port};

    my $queue = $transaction->notes("queue") || {};
    my $rcpt  = $recipient->user . "@" . $recipient->host;
    
    $queue->{$rcpt}->{destination} = "local";
    $queue->{$rcpt}->{protocol} = "lmtp";
    $queue->{$rcpt}->{host} = $hostname;
    $queue->{$rcpt}->{port} = $port;
    $queue->{$rcpt}->{user} = $username;
    
    $transaction->notes("queue", $queue);

    $self->log(LOGNOTICE, "Setting LMTP server to dovecot on $hostname:$port for user: $username");

    return 1;
}

sub CheckRecipient
{
    my ($self, $recipient) = @_;

    $self->connect();
    $self->createStatements();

    my $result = $self->{rcpt_sth}->execute($recipient->user, $recipient->host);
    if (!$result) 
    {
        $self->log(LOGERROR, "Failed to fetch recipient information from the database");        return -1;
    }

    if ($self->{rcpt_sth}->rows == 1)
    {
        $self->log(LOGDEBUG, " found recipient in database");

        return 1;
    }
    elsif ($self->{rcpt_sth}->rows > 1)
    {
        $self->log(LOGERROR,"found multiple users for same recipient in database. Something wrong with database? (" . $recipient->user . '@' . $recipient->host . ")" );
        return -2;
    }

    return 0;
}

sub hook_quit {
    my ($self, $transaction) = @_;

    $self->disconnect();
}

sub hook_rcpt {
    my ($self, $transaction, $recipient) = @_;

    $self->log(LOGNOTICE, "Recipient: " . $recipient->user . "@" . $recipient->host);

    return DECLINED unless $recipient->host && $recipient->user;
    
    
    my $rcptValid = $self->CheckRecipient($recipient);
    
    if ($rcptValid == 1 )
    {
        $self->updateTransactionWithLmtpInfo($transaction, $recipient) || return DENYSOFT, "Temporary failure, try again later";
        return OK;
    }
    elsif( $self->is_immune())
    {
        $self->updateTransactionWithSmtpInfo($transaction, $recipient) || return DENYSOFT, "Temporary failure, try again later";
        return OK;
    }
    elsif ($rcptValid == -1)
    {
        return DENYSOFT, "Temporary failure, try again later";
    }


    return Qpsmtpd::DSN->relaying_denied();    
}