<?php
/**
 * Piwik - free/libre analytics platform
 *
 * @link http://piwik.org
 * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
 */

namespace Piwik;

use Piwik\DataAccess\RawLogDao;
use Piwik\Plugin\LogTablesProvider;

/**
 * Service that deletes log entries. Methods in this class cascade, so deleting visits will delete visit actions,
 * conversions and conversion items.
 */
class LogDeleter
{
    /**
     * @var RawLogDao
     */
    private $rawLogDao;

    /**
     * @var LogTablesProvider
     */
    private $logTablesProvider;

    public function __construct(RawLogDao $rawLogDao, LogTablesProvider $logTablesProvider)
    {
        $this->rawLogDao = $rawLogDao;
        $this->logTablesProvider = $logTablesProvider;
    }

    /**
     * Deletes visits by ID. This method cascades, so conversions, conversion items and visit actions for
     * the visits are also deleted.
     *
     * @param int[] $visitIds
     * @return int The number of deleted visits.
     */
    public function deleteVisits($visitIds)
    {
        $numDeletedVisits = 0;

        foreach ($this->logTablesProvider->getAllLogTables() as $logTable) {
            if ($logTable->getColumnToJoinOnIdVisit()) {
                $numVisits = $this->rawLogDao->deleteFromLogTable($logTable->getName(), $visitIds);
                if ($logTable->getName() === 'log_visit') {
                    $numDeletedVisits = $numVisits;
                }
            }
        }

        return $numDeletedVisits;
    }

    /**
     * Deletes visits within the specified date range and belonging to the specified site (if any). Visits are
     * deleted in chunks, so only `$iterationStep` visits are deleted at a time.
     *
     * @param string|null $startDatetime A datetime string. Visits that occur at this time or after are deleted. If not supplied,
     *                                   visits from the beginning of time are deleted.
     * @param string|null $endDatetime A datetime string. Visits that occur before this time are deleted. If not supplied,
     *                                 visits from the end of time are deleted.
     * @param int|null $idSite The site to delete visits from.
     * @param int $iterationStep The number of visits to delete at a single time.
     * @param callable $afterChunkDeleted Callback executed after every chunk of visits are deleted.
     * @return int The number of visits deleted.
     */
    public function deleteVisitsFor($startDatetime, $endDatetime, $idSite = null, $iterationStep = 1000, $afterChunkDeleted = null)
    {
        $fields = array('idvisit');
        $conditions = array();

        if (!empty($startDatetime)) {
            $conditions[] = array('visit_last_action_time', '>=', $startDatetime);
        }

        if (!empty($endDatetime)) {
            $conditions[] = array('visit_last_action_time', '<', $endDatetime);
        }

        if (!empty($idSite)) {
            $conditions[] = array('idsite', '=', $idSite);
        }

        $logsDeleted = 0;
        $logPurger = $this;
        $this->rawLogDao->forAllLogs('log_visit', $fields, $conditions, $iterationStep, function ($logs) use ($logPurger, &$logsDeleted, $afterChunkDeleted) {
            $ids = array_map(function ($row) { return reset($row); }, $logs);
            $logsDeleted += $logPurger->deleteVisits($ids);

            if (!empty($afterChunkDeleted)) {
                $afterChunkDeleted($logsDeleted);
            }
        });

        return $logsDeleted;
    }
}