<?php

namespace Icinga\Module\Businessprocess\State;

use Exception;
use Icinga\Application\Benchmark;
use Icinga\Data\Filter\Filter;
use Icinga\Module\Businessprocess\BpConfig;
use Icinga\Module\Monitoring\Backend\MonitoringBackend;

class MonitoringState
{
    /** @var BpConfig */
    protected $config;

    /** @var MonitoringBackend */
    protected $backend;

    private function __construct(BpConfig $config)
    {
        $this->config = $config;
        $this->backend = $config->getBackend();
    }

    public static function apply(BpConfig $config)
    {
        $self = new static($config);
        $self->retrieveStatesFromBackend();
        return $config;
    }

    public function retrieveStatesFromBackend()
    {
        $config = $this->config;

        try {
            $this->reallyRetrieveStatesFromBackend();
        } catch (Exception $e) {
            $config->addError(
                $config->translate('Could not retrieve process state: %s'),
                $e->getMessage()
            );
        }
    }

    public function reallyRetrieveStatesFromBackend()
    {
        $config = $this->config;

        Benchmark::measure('Retrieving states for business process ' . $config->getName());
        $backend = $this->backend;
        $hostFilter = $config->listInvolvedHostNames();

        if ($config->usesHardStates()) {
            $hostStateColumn          = 'host_hard_state';
            $hostStateChangeColumn    = 'host_last_hard_state_change';
            $serviceStateColumn       = 'service_hard_state';
            $serviceStateChangeColumn = 'service_last_hard_state_change';
        } else {
            $hostStateColumn          = 'host_state';
            $hostStateChangeColumn    = 'host_last_state_change';
            $serviceStateColumn       = 'service_state';
            $serviceStateChangeColumn = 'service_last_state_change';
        }
        $filter = Filter::matchAny();
        foreach ($hostFilter as $host) {
            $filter->addFilter(Filter::where('host_name', $host));
        }

        if ($filter->isEmpty()) {
            return $this;
        }

        $hostStatus = $backend->select()->from('hostStatus', array(
            'hostname'          => 'host_name',
            'last_state_change' => $hostStateChangeColumn,
            'in_downtime'       => 'host_in_downtime',
            'ack'               => 'host_acknowledged',
            'state'             => $hostStateColumn
        ))->applyFilter($filter)->getQuery()->fetchAll();

        $serviceStatus = $backend->select()->from('serviceStatus', array(
            'hostname'          => 'host_name',
            'service'           => 'service_description',
            'last_state_change' => $serviceStateChangeColumn,
            'in_downtime'       => 'service_in_downtime',
            'ack'               => 'service_acknowledged',
            'state'             => $serviceStateColumn
        ))->applyFilter($filter)->getQuery()->fetchAll();

        foreach ($serviceStatus as $row) {
            $this->handleDbRow($row, $config);
        }

        foreach ($hostStatus as $row) {
            $this->handleDbRow($row, $config);
        }
        // TODO: Union, single query?
        Benchmark::measure('Got states for business process ' . $config->getName());

        return $this;
    }

    protected function handleDbRow($row, BpConfig $config)
    {
        $key = $row->hostname;
        if (property_exists($row, 'service')) {
            $key .= ';' . $row->service;
        } else {
            $key .= ';Hoststatus';
        }

        // We fetch more states than we need, so skip unknown ones
        if (! $config->hasNode($key)) {
            return;
        }

        $node = $config->getNode($key);

        if ($row->state !== null) {
            $node->setState($row->state)->setMissing(false);
        }
        if ($row->last_state_change !== null) {
            $node->setLastStateChange($row->last_state_change);
        }
        if ((int) $row->in_downtime === 1) {
            $node->setDowntime(true);
        }
        if ((int) $row->ack === 1) {
            $node->setAck(true);
        }
    }
}