<?php

// SPDX-FileCopyrightText: 2018 Icinga GmbH <https://icinga.com>
// SPDX-License-Identifier: GPL-3.0-or-later

namespace Icinga\Module\Graphite\Graphing;

use Icinga\Data\Fetchable;
use Icinga\Data\Filter\Filter;
use Icinga\Data\Filterable;
use Icinga\Data\Queryable;
use Icinga\Exception\NotImplementedError;
use Icinga\Module\Graphite\GraphiteUtil;
use Icinga\Module\Graphite\Util\IcingadbUtils;
use Icinga\Module\Graphite\Util\MacroTemplate;
use Icinga\Module\Graphite\Util\InternalProcessTracker as IPT;
use Icinga\Module\Icingadb\Compat\UrlMigrator;
use Icinga\Module\Icingadb\Model\Host;
use Icinga\Module\Monitoring\Object\Macro;
use Icinga\Module\Monitoring\Object\MonitoredObject;
use Icinga\Util\Json;
use Icinga\Web\Url;
use InvalidArgumentException;
use ipl\Orm\Model;
use ipl\Stdlib\Filter as IplFilter;

/**
 * Queries a {@link MetricsDataSource}
 */
class MetricsQuery implements Queryable, Filterable, Fetchable
{
    /**
     * @var MetricsDataSource
     */
    protected $dataSource;

    /**
     * The base metrics pattern
     *
     * @var MacroTemplate
     */
    protected $base;

    /**
     * Extension of {@link base}
     *
     * @var string[]
     */
    protected $filter = [];

    /**
     * The object to render the graphs for
     *
     * @var MonitoredObject|Model
     */
    protected $object;

    /**
     * Constructor
     *
     * @param   MetricsDataSource   $dataSource
     */
    public function __construct(MetricsDataSource $dataSource)
    {
        $this->dataSource = $dataSource;
    }

    public function from($target, ?array $fields = null)
    {
        if ($fields !== null) {
            throw new InvalidArgumentException('Fields are not applicable to this kind of query');
        }

        try {
            $this->base = $target instanceof MacroTemplate ? $target : new MacroTemplate((string) $target);
        } catch (InvalidArgumentException $e) {
            throw new InvalidArgumentException('Bad target', $e->getCode(), $e);
        }

        return $this;
    }

    public function applyFilter(Filter $filter)
    {
        throw new NotImplementedError(__METHOD__);
    }

    public function setFilter(Filter $filter)
    {
        throw new NotImplementedError(__METHOD__);
    }

    public function getFilter()
    {
        throw new NotImplementedError(__METHOD__);
    }

    public function addFilter(Filter $filter)
    {
        throw new NotImplementedError(__METHOD__);
    }

    public function where($condition, $value = null)
    {
        $this->filter[$condition] = $this->escapeMetricStep($value);

        return $this;
    }

    public function fetchAll()
    {
        $result = [];
        foreach ($this->fetchColumn() as $metric) {
            $result[] = (object) ['metric' => $metric];
        }

        return $result;
    }

    public function fetchRow()
    {
        $result = $this->fetchColumn();
        return empty($result) ? false : (object) ['metric' => $result[0]];
    }

    public function fetchColumn()
    {
        $filter = [];
        foreach ($this->base->getMacros() as $macro) {
            if (isset($this->filter[$macro])) {
                $filter[$macro] = $this->filter[$macro];
                continue;
            }

            if (strpos($macro, '.') === false) {
                continue;
            }

            $workaroundMacro = str_replace('.', '_', $macro);
            if ($this->object instanceof Model) {
                // icingadb macro
                $tranformFilter = UrlMigrator::transformFilter(
                    IplFilter::equal($workaroundMacro, ''),
                    $this->object instanceof Host ? 'hosts' : 'services'
                );

                if ($tranformFilter === false) {
                    continue;
                }

                $migratedMacro = $tranformFilter->getColumn();

                if ($migratedMacro === $workaroundMacro) {
                    $workaroundMacro = $macro;
                } else {
                    $workaroundMacro = $migratedMacro;
                }

                $icingadbMacros = IcingadbUtils::getInstance();
                $result = $icingadbMacros->resolveMacro($workaroundMacro, $this->object);
            } else {
                if ($workaroundMacro === 'service_name') {
                    $workaroundMacro = 'service_description';
                }

                $result = Macro::resolveMacro($workaroundMacro, $this->object);
            }

            if ($result !== $workaroundMacro) {
                $filter[$macro] = $this->escapeMetricStep($result);
            }
        }

        $client = $this->dataSource->getClient();
        $url = Url::fromPath('metrics/expand', [
            'query' => $this->base->resolve($filter, '*')
        ]);
        $res = Json::decode($client->request($url));
        natsort($res->results);

        IPT::recordf('Fetched %s metric(s) from %s', count($res->results), (string) $client->completeUrl($url));

        return array_values($res->results);
    }

    public function fetchOne()
    {
        $result = $this->fetchColumn();
        return empty($result) ? false : $result[0];
    }

    public function fetchPairs()
    {
        throw new NotImplementedError(__METHOD__);
    }

    /**
     * Set the object to render the graphs for
     *
     * @param MonitoredObject|Model $object
     *
     * @return $this
     */
    public function setObject($object)
    {
        $this->object = $object;

        return $this;
    }

    /**
     * Escapes a string for usage in a Graphite metric path between two dots
     *
     * @param   string  $step
     *
     * @return  string
     */
    protected function escapeMetricStep($step)
    {
        return preg_replace('/[^a-zA-Z0-9\*\-:^[\]$#%\']/', '_', $step);
    }
}
