#
# Copyright 2024 Centreon (http://www.centreon.com/)
#
# Centreon is a full-fledged industry-strength solution that meets
# the needs in IT infrastructure and application monitoring for
# service performance.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

package database::postgres::mode::hitratio;

use base qw(centreon::plugins::mode);

use strict;
use warnings;
use centreon::plugins::statefile;

sub new {
    my ($class, %options) = @_;
    my $self = $class->SUPER::new(package => __PACKAGE__, %options, force_new_perfdata => 1);
    bless $self, $class;

    $options{options}->add_options(arguments => { 
        'warning:s'  => { name => 'warning' },
        'critical:s' => { name => 'critical' },
        'lookback'   => { name => 'lookback' },
        'exclude:s'  => { name => 'exclude' }
    });

    $self->{statefile_cache} = centreon::plugins::statefile->new(%options);

    return $self;
}

sub check_options {
    my ($self, %options) = @_;
    $self->SUPER::init(%options);

    if (($self->{perfdata}->threshold_validate(label => 'warning', value => $self->{option_results}->{warning})) == 0) {
        $self->{output}->add_option_msg(short_msg => "Wrong warning threshold '" . $self->{option_results}->{warning} . "'.");
        $self->{output}->option_exit();
    }
    if (($self->{perfdata}->threshold_validate(label => 'critical', value => $self->{option_results}->{critical})) == 0) {
        $self->{output}->add_option_msg(short_msg => "Wrong critical threshold '" . $self->{option_results}->{critical} . "'.");
        $self->{output}->option_exit();
    }

    $self->{statefile_cache}->check_options(%options);
}

sub run {
    my ($self, %options) = @_;

    $options{sql}->connect();

    $options{sql}->query(query => q{
        SELECT sd.blks_hit, sd.blks_read, d.datname
        FROM pg_stat_database sd, pg_database d
        WHERE d.oid=sd.datid
    });

    $self->{statefile_cache}->read(statefile => 'postgres_' . $self->{mode} . '_' . $options{sql}->get_unique_id4save());
    my $old_timestamp = $self->{statefile_cache}->get(name => 'last_timestamp');

    my $database_check = 0;
    my $new_datas = {};
    $new_datas->{last_timestamp} = time();
    my $result = $options{sql}->fetchall_arrayref();

    $self->{output}->output_add(
        severity => 'OK',
        short_msg => "All databases hitratio are ok"
    );

    foreach my $row (@{$result}) {
        $new_datas->{$row->[2] . '_blks_hit'} = $row->[0];
        $new_datas->{$row->[2] . '_blks_read'} = $row->[1];

        if (defined($self->{option_results}->{exclude}) && $self->{option_results}->{exclude} ne '' && $row->[2] =~ /$self->{option_results}->{exclude}/) {
            $self->{output}->output_add(long_msg => "Skipping database '" . $row->[2] . '"');
            next;
        }

        my $old_blks_hit = $self->{statefile_cache}->get(name => $row->[2] . '_blks_hit');
        my $old_blks_read = $self->{statefile_cache}->get(name => $row->[2] . '_blks_read');

        next if (!defined($old_blks_hit) || !defined($old_blks_read));
        $old_blks_hit = 0 if ($row->[0] < $old_blks_hit);
        $old_blks_read = 0 if ($row->[1] < $old_blks_read);

        $database_check++;
        my %prcts = ();
        my $total_read_requests = $new_datas->{$row->[2] . '_blks_hit'} - $old_blks_hit;
        my $total_read_disk = $new_datas->{$row->[2] . '_blks_read'} - $old_blks_read;
        $prcts{hitratio_now} = (($total_read_requests + $total_read_disk) == 0) ? 100 : $total_read_requests * 100 / ($total_read_requests + $total_read_disk);
        $prcts{hitratio} = (($new_datas->{$row->[2] . '_blks_hit'} + + $new_datas->{$row->[2] . '_blks_read'}) == 0) ? 100 : $new_datas->{$row->[2] . '_blks_hit'} * 100 / ($new_datas->{$$row[2] . '_blks_hit'} + $new_datas->{$row->[2] . '_blks_read'});

        my $exit_code = $self->{perfdata}->threshold_check(value => $prcts{'hitratio' . ((defined($self->{option_results}->{lookback})) ? '' : '_now' )}, threshold => [ { label => 'critical', 'exit_litteral' => 'critical' }, { label => 'warning', exit_litteral => 'warning' } ]);
        $self->{output}->output_add(
            long_msg => sprintf(
                "Database '%s' hitratio at %.2f%%", 
                $row->[2], $prcts{'hitratio' . ((defined($self->{option_results}->{lookback})) ? '' : '_now')}
            )
        );

        if (!$self->{output}->is_status(value => $exit_code, compare => 'ok', litteral => 1)) {
            $self->{output}->output_add(
                severity => $exit_code,
                short_msg => sprintf(
                    "Database '%s' hitratio at %.2f%%", 
                    $row->[2], $prcts{'hitratio' . ((defined($self->{option_results}->{lookback})) ? '' : '_now')})
            );
        }
        $self->{output}->perfdata_add(
            nlabel => 'database.hitratio' . ((defined($self->{option_results}->{lookback})) ? '.delta' : '.average') . '.percentage',
            unit => '%',
            instances => $row->[2],
            value => sprintf('%.2f', $prcts{'hitratio' . ((defined($self->{option_results}->{lookback})) ? '' : '_now')}),
            warning => $self->{perfdata}->get_perfdata_for_output(label => 'warning'),
            critical => $self->{perfdata}->get_perfdata_for_output(label => 'critical'),
            min => 0, max => 100
        );
        $self->{output}->perfdata_add(
            nlabel => 'database.hitratio' . ((defined($self->{option_results}->{lookback})) ? '.average' : '.delta') . '.percentage',
            unit => '%',
            instances => $row->[2],
            value => sprintf('%.2f', $prcts{'hitratio' . ((defined($self->{option_results}->{lookback})) ? '_now' : '')}),
            min => 0, max => 100
        );
    }

    $self->{statefile_cache}->write(data => $new_datas); 
    if (!defined($old_timestamp)) {
        $self->{output}->output_add(
            severity => 'OK',
            short_msg => "Buffer creation..."
        );
    }

    if (defined($old_timestamp) && $database_check == 0) {
        $self->{output}->output_add(
            severity => 'UNKNOWN',
            short_msg => 'No database checked (permission or a wrong exclude filter)'
        );
    }

    $self->{output}->display();
    $self->{output}->exit();
}

1;

__END__

=head1 MODE

Check hit ratio (in buffer cache) for databases.

=over 8

=item B<--warning>

Warning threshold.

=item B<--critical>

Critical threshold.

=item B<--lookback>

Threshold isn't on the percent calculated from the difference ('xxx_hitratio_now').

=item B<--exclude>

Filter databases.

=back

=cut
