<?php

namespace Icinga\Module\Director\Import\PurgeStrategy;

use Icinga\Module\Director\Import\SyncUtils;
use Icinga\Module\Director\Objects\ImportRun;
use Icinga\Module\Director\Objects\ImportSource;

class ImportRunBasedPurgeStrategy extends PurgeStrategy
{
    public function listObjectsToPurge()
    {
        $remove = array();

        foreach ($this->getSyncRule()->fetchInvolvedImportSources() as $source) {
            $remove += $this->checkImportSource($source);
        }

        return $remove;
    }

    protected function getLastSync()
    {
        return strtotime($this->getSyncRule()->getLastSyncTimestamp());
    }

    // TODO: NAMING!
    protected function checkImportSource(ImportSource $source)
    {
        if (null === ($lastSync = $this->getLastSync())) {
            // No last sync, nothing to purge
            return array();
        }

        $runA = $source->fetchLastRunBefore($lastSync);
        if ($runA === null) {
            // Nothing to purge for this source
            return array();
        }

        $runB = $source->fetchLastRun();
        if ($runA->rowset_checksum === $runB->rowset_checksum) {
            // Same source data, nothing to purge
            return array();
        }

        return $this->listKeysRemovedBetween($runA, $runB);
    }

    public function listKeysRemovedBetween(ImportRun $runA, ImportRun $runB)
    {
        $rule = $this->getSyncRule();
        $db = $rule->getDb();

        $selectA = $runA->prepareImportedObjectQuery();
        $selectB = $runB->prepareImportedObjectQuery();

        $query = $db->select()->from(
            array('a' => $selectA),
            'a.object_name'
        )->where('a.object_name NOT IN (?)', $selectB);

        $result = $db->fetchCol($query);

        if (empty($result)) {
            return array();
        }

        if ($rule->hasCombinedKey()) {
            $pattern = $rule->getSourceKeyPattern();
            $columns = SyncUtils::getRootVariables(
                SyncUtils::extractVariableNames($pattern)
            );
            $resultForCombinedKey = array();
            foreach (array_chunk($result, 1000) as $keys) {
                $rows = $runA->fetchRows($columns, null, $keys);
                foreach ($rows as $row) {
                    $resultForCombinedKey[] = SyncUtils::fillVariables($pattern, $row);
                }
            }
            $result = $resultForCombinedKey;
        }

        if (empty($result)) {
            return array();
        }

        return array_combine($result, $result);
    }
}